Re: [AFMUG] Elevation question
I just did some digging. Their service is not available in my area. Other lower precision services are. But if it grows here they may give the state network a run for their money. From: ch...@wbmfg.com Sent: Friday, May 8, 2020 8:24 AM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question The price is not good compared to my $600/year for 2cm accuracy. I wonder how they deliver this? From: Mike Hammett Sent: Friday, May 8, 2020 6:56 AM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question https://catalyst.seilergeo.com/catalyst-wizard/ It looks very attractive. - Mike Hammett Intelligent Computing Solutions Midwest Internet Exchange The Brothers WISP From: fiber...@mail.com To: af@af.afmug.com Sent: Wednesday, May 6, 2020 4:42:00 PM Subject: Re: [AFMUG] Elevation question FYI, Trimble has an RTK receiver with a pay-as-you-go plan. The receiver (Trimble Catalyst DA-1) is $300-$400 and with that you select a plan according to your accuracy needs: 1 centimeter to 1 meter Plans are available in increments from hourly to yearly. The Catalyst is supposedly fairly good compared to it's industrial bigger bredren (less than an inch offset in survery results). You'll need an Android device to use the receiver, as it has no screen. If you want to roll your own RTK solution, then there's a Taiwanese company that will sell you receivers and basestations for a few hundred dollars each. https://www.polaris-gnss.com/ Disclaimer: I haven't used these yet. I have an upcoming mapping project this summer then I might get some quality hands on time. > Sent: Wednesday, May 06, 2020 > From: ch...@wbmfg.com > To: "AnimalFarm Microwave Users Group" > Subject: Re: [AFMUG] Elevation question > > $600/year here in Utah... > > -Original Message- > From: Mark Radabaugh > Sent: Wednesday, May 6, 2020 9:57 AM > To: AnimalFarm Microwave Users Group > Subject: Re: [AFMUG] Elevation question > > Josh, > > In Ohio ODOT has a statewide RTK system set up that you can get free access > too. It’s accessible over the internet so as long as your GPS receiver can > connect to your phone to make the data connection to the state RTK system > you can use the data. > > ODOT built if for their own use but make it available to the public to use. > I believe in some locations they will set up a 900Mhz or similar repeater > system to broadcast the data but most of the time they just use cellular > data links. > > Mark > > > On May 6, 2020, at 11:37 AM, Brian Webster > > wrote: > > > > https://en.wikipedia.org/wiki/Real-time_kinematic > > > > Real-time kinematic (RTK) positioning is a satellite navigation technique > > used to enhance the precision of position data derived from > > satellite-based positioning systems (global navigation satellite systems, > > GNSS) such as GPS, GLONASS, Galileo, NavIC and BeiDou. It uses > > measurements of the phase of the signal's carrier wave in addition to the > > information content of the signal and relies on a single reference station > > or interpolated virtual station to provide real-time corrections, > > providing up to centimetre-level accuracy.[1] With reference to GPS in > > particular, the system is commonly referred to as carrier-phase > > enhancement, or CPGPS.[2] It has applications in land survey, hydrographic > > survey, and in unmanned aerial vehicle navigation. > > > > > > > > Thank you, > > Brian Webster > > www.wirelessmapping.com > > > > From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Brian Webster > > Sent: Wednesday, May 6, 2020 11:33 AM > > To: 'AnimalFarm Microwave Users Group' > > Subject: Re: [AFMUG] Elevation question > > > > High end stuff. I never trust any consumer grade GPS device altitude > > readings. I have seen them off by as much as 300 to 400 feet. High end GPS > > devices rely on either a real time data link to ground reference stations > > or they post process the data back at the office. This is a process where > > you time sync your data with the ground reference stations, calculate the > > timing difference based on your location distance from the ground control > > points. The ground control points have a known coordinate and altitude. > > They then compare the GPS readings at their point for those time reference > > points you process against. They calculate the correction factor from the > > GPS against the known point, then also correct your data based on the > > distance/time from the ground station and correct your data.
Re: [AFMUG] Elevation question
The price is not good compared to my $600/year for 2cm accuracy. I wonder how they deliver this? From: Mike Hammett Sent: Friday, May 8, 2020 6:56 AM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question https://catalyst.seilergeo.com/catalyst-wizard/ It looks very attractive. - Mike Hammett Intelligent Computing Solutions Midwest Internet Exchange The Brothers WISP From: fiber...@mail.com To: af@af.afmug.com Sent: Wednesday, May 6, 2020 4:42:00 PM Subject: Re: [AFMUG] Elevation question FYI, Trimble has an RTK receiver with a pay-as-you-go plan. The receiver (Trimble Catalyst DA-1) is $300-$400 and with that you select a plan according to your accuracy needs: 1 centimeter to 1 meter Plans are available in increments from hourly to yearly. The Catalyst is supposedly fairly good compared to it's industrial bigger bredren (less than an inch offset in survery results). You'll need an Android device to use the receiver, as it has no screen. If you want to roll your own RTK solution, then there's a Taiwanese company that will sell you receivers and basestations for a few hundred dollars each. https://www.polaris-gnss.com/ Disclaimer: I haven't used these yet. I have an upcoming mapping project this summer then I might get some quality hands on time. > Sent: Wednesday, May 06, 2020 > From: ch...@wbmfg.com > To: "AnimalFarm Microwave Users Group" > Subject: Re: [AFMUG] Elevation question > > $600/year here in Utah... > > -Original Message- > From: Mark Radabaugh > Sent: Wednesday, May 6, 2020 9:57 AM > To: AnimalFarm Microwave Users Group > Subject: Re: [AFMUG] Elevation question > > Josh, > > In Ohio ODOT has a statewide RTK system set up that you can get free access > too. It’s accessible over the internet so as long as your GPS receiver can > connect to your phone to make the data connection to the state RTK system > you can use the data. > > ODOT built if for their own use but make it available to the public to use. > I believe in some locations they will set up a 900Mhz or similar repeater > system to broadcast the data but most of the time they just use cellular > data links. > > Mark > > > On May 6, 2020, at 11:37 AM, Brian Webster > > wrote: > > > > https://en.wikipedia.org/wiki/Real-time_kinematic > > > > Real-time kinematic (RTK) positioning is a satellite navigation technique > > used to enhance the precision of position data derived from > > satellite-based positioning systems (global navigation satellite systems, > > GNSS) such as GPS, GLONASS, Galileo, NavIC and BeiDou. It uses > > measurements of the phase of the signal's carrier wave in addition to the > > information content of the signal and relies on a single reference station > > or interpolated virtual station to provide real-time corrections, > > providing up to centimetre-level accuracy.[1] With reference to GPS in > > particular, the system is commonly referred to as carrier-phase > > enhancement, or CPGPS.[2] It has applications in land survey, hydrographic > > survey, and in unmanned aerial vehicle navigation. > > > > > > > > Thank you, > > Brian Webster > > www.wirelessmapping.com > > > > From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Brian Webster > > Sent: Wednesday, May 6, 2020 11:33 AM > > To: 'AnimalFarm Microwave Users Group' > > Subject: Re: [AFMUG] Elevation question > > > > High end stuff. I never trust any consumer grade GPS device altitude > > readings. I have seen them off by as much as 300 to 400 feet. High end GPS > > devices rely on either a real time data link to ground reference stations > > or they post process the data back at the office. This is a process where > > you time sync your data with the ground reference stations, calculate the > > timing difference based on your location distance from the ground control > > points. The ground control points have a known coordinate and altitude. > > They then compare the GPS readings at their point for those time reference > > points you process against. They calculate the correction factor from the > > GPS against the known point, then also correct your data based on the > > distance/time from the ground station and correct your data. For older GPS > > units you sometimes had to occupy a point for a longer period of time > > based on your distances from the control points. > > > > High end GPS units can also do RTK or real time kinematic data collection. > > This is done by either having a GPS base station controller that is r
Re: [AFMUG] Elevation question
https://catalyst.seilergeo.com/catalyst-wizard/ It looks very attractive. - Mike Hammett Intelligent Computing Solutions Midwest Internet Exchange The Brothers WISP - Original Message - From: fiber...@mail.com To: af@af.afmug.com Sent: Wednesday, May 6, 2020 4:42:00 PM Subject: Re: [AFMUG] Elevation question FYI, Trimble has an RTK receiver with a pay-as-you-go plan. The receiver (Trimble Catalyst DA-1) is $300-$400 and with that you select a plan according to your accuracy needs: 1 centimeter to 1 meter Plans are available in increments from hourly to yearly. The Catalyst is supposedly fairly good compared to it's industrial bigger bredren (less than an inch offset in survery results). You'll need an Android device to use the receiver, as it has no screen. If you want to roll your own RTK solution, then there's a Taiwanese company that will sell you receivers and basestations for a few hundred dollars each. https://www.polaris-gnss.com/ Disclaimer: I haven't used these yet. I have an upcoming mapping project this summer then I might get some quality hands on time. > Sent: Wednesday, May 06, 2020 > From: ch...@wbmfg.com > To: "AnimalFarm Microwave Users Group" > Subject: Re: [AFMUG] Elevation question > > $600/year here in Utah... > > -Original Message- > From: Mark Radabaugh > Sent: Wednesday, May 6, 2020 9:57 AM > To: AnimalFarm Microwave Users Group > Subject: Re: [AFMUG] Elevation question > > Josh, > > In Ohio ODOT has a statewide RTK system set up that you can get free access > too. It’s accessible over the internet so as long as your GPS receiver can > connect to your phone to make the data connection to the state RTK system > you can use the data. > > ODOT built if for their own use but make it available to the public to use. > I believe in some locations they will set up a 900Mhz or similar repeater > system to broadcast the data but most of the time they just use cellular > data links. > > Mark > > > On May 6, 2020, at 11:37 AM, Brian Webster > > wrote: > > > > https://en.wikipedia.org/wiki/Real-time_kinematic > > > > Real-time kinematic (RTK) positioning is a satellite navigation technique > > used to enhance the precision of position data derived from > > satellite-based positioning systems (global navigation satellite systems, > > GNSS) such as GPS, GLONASS, Galileo, NavIC and BeiDou. It uses > > measurements of the phase of the signal's carrier wave in addition to the > > information content of the signal and relies on a single reference station > > or interpolated virtual station to provide real-time corrections, > > providing up to centimetre-level accuracy.[1] With reference to GPS in > > particular, the system is commonly referred to as carrier-phase > > enhancement, or CPGPS.[2] It has applications in land survey, hydrographic > > survey, and in unmanned aerial vehicle navigation. > > > > > > > > Thank you, > > Brian Webster > > www.wirelessmapping.com > > > > From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Brian Webster > > Sent: Wednesday, May 6, 2020 11:33 AM > > To: 'AnimalFarm Microwave Users Group' > > Subject: Re: [AFMUG] Elevation question > > > > High end stuff. I never trust any consumer grade GPS device altitude > > readings. I have seen them off by as much as 300 to 400 feet. High end GPS > > devices rely on either a real time data link to ground reference stations > > or they post process the data back at the office. This is a process where > > you time sync your data with the ground reference stations, calculate the > > timing difference based on your location distance from the ground control > > points. The ground control points have a known coordinate and altitude. > > They then compare the GPS readings at their point for those time reference > > points you process against. They calculate the correction factor from the > > GPS against the known point, then also correct your data based on the > > distance/time from the ground station and correct your data. For older GPS > > units you sometimes had to occupy a point for a longer period of time > > based on your distances from the control points. > > > > High end GPS units can also do RTK or real time kinematic data collection. > > This is done by either having a GPS base station controller that is real > > time data linked to ground control stations or that the rover unit has the > > real time data connectivity. They do all the above processing steps in > > real time, no post processing after the field work is
Re: [AFMUG] Elevation question
Lots cheaper than what I am using... -Original Message- From: Dev Sent: Wednesday, May 6, 2020 4:06 PM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question From their site: $160-325/year, depending if you get the gold plated steering wheel. Anyone gets one let us know how it goes? How much code do you have to build yourself to integrate it in a meaningful way with standard tools widely available? On May 6, 2020, at 2:48 PM, ch...@wbmfg.com wrote: So what do the plans cost? -Original Message- From: fiber...@mail.com Sent: Wednesday, May 6, 2020 3:42 PM To: af@af.afmug.com Subject: Re: [AFMUG] Elevation question FYI, Trimble has an RTK receiver with a pay-as-you-go plan. The receiver (Trimble Catalyst DA-1) is $300-$400 and with that you select a plan according to your accuracy needs: 1 centimeter to 1 meter Plans are available in increments from hourly to yearly. The Catalyst is supposedly fairly good compared to it's industrial bigger bredren (less than an inch offset in survery results). You'll need an Android device to use the receiver, as it has no screen. If you want to roll your own RTK solution, then there's a Taiwanese company that will sell you receivers and basestations for a few hundred dollars each. https://www.polaris-gnss.com/ Disclaimer: I haven't used these yet. I have an upcoming mapping project this summer then I might get some quality hands on time. Sent: Wednesday, May 06, 2020 From: ch...@wbmfg.com To: "AnimalFarm Microwave Users Group" Subject: Re: [AFMUG] Elevation question $600/year here in Utah... -Original Message- From: Mark Radabaugh Sent: Wednesday, May 6, 2020 9:57 AM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question Josh, In Ohio ODOT has a statewide RTK system set up that you can get free access too. It’s accessible over the internet so as long as your GPS receiver can connect to your phone to make the data connection to the state RTK system you can use the data. ODOT built if for their own use but make it available to the public to use. I believe in some locations they will set up a 900Mhz or similar repeater system to broadcast the data but most of the time they just use cellular data links. Mark > On May 6, 2020, at 11:37 AM, Brian Webster > wrote: > > https://en.wikipedia.org/wiki/Real-time_kinematic > > Real-time kinematic (RTK) positioning is a satellite navigation > > technique > used to enhance the precision of position data derived from > satellite-based positioning systems (global navigation satellite > > systems, > GNSS) such as GPS, GLONASS, Galileo, NavIC and BeiDou. It uses > measurements of the phase of the signal's carrier wave in addition to > > the > information content of the signal and relies on a single reference > > station > or interpolated virtual station to provide real-time corrections, > providing up to centimetre-level accuracy.[1] With reference to GPS in > particular, the system is commonly referred to as carrier-phase > enhancement, or CPGPS.[2] It has applications in land survey, > > hydrographic > survey, and in unmanned aerial vehicle navigation. > > > > Thank you, > Brian Webster > www.wirelessmapping.com > > From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Brian Webster > Sent: Wednesday, May 6, 2020 11:33 AM > To: 'AnimalFarm Microwave Users Group' > Subject: Re: [AFMUG] Elevation question > > High end stuff. I never trust any consumer grade GPS device altitude > readings. I have seen them off by as much as 300 to 400 feet. High end > > GPS > devices rely on either a real time data link to ground reference > > stations > or they post process the data back at the office. This is a process > > where > you time sync your data with the ground reference stations, calculate > > the > timing difference based on your location distance from the ground > > control > points. The ground control points have a known coordinate and altitude. > They then compare the GPS readings at their point for those time > > reference > points you process against. They calculate the correction factor from > > the > GPS against the known point, then also correct your data based on the > distance/time from the ground station and correct your data. For older > > GPS > units you sometimes had to occupy a point for a longer period of time > based on your distances from the control points. > > High end GPS units can also do RTK or real time kinematic data > > collection. > This is done by either having a GPS base station controller that is > real > time data linked to ground control stations or that the rover unit has > > the > real time data connectivity. They do all the above pr
Re: [AFMUG] Elevation question
From their site: $160-325/year, depending if you get the gold plated steering wheel. Anyone gets one let us know how it goes? How much code do you have to build yourself to integrate it in a meaningful way with standard tools widely available? > On May 6, 2020, at 2:48 PM, ch...@wbmfg.com wrote: > > So what do the plans cost? > > -Original Message- From: fiber...@mail.com > Sent: Wednesday, May 6, 2020 3:42 PM > To: af@af.afmug.com > Subject: Re: [AFMUG] Elevation question > > FYI, Trimble has an RTK receiver with a pay-as-you-go plan. The receiver > (Trimble Catalyst DA-1) is $300-$400 and with that you select a plan > according to your accuracy needs: 1 centimeter to 1 meter > Plans are available in increments from hourly to yearly. The Catalyst is > supposedly fairly good compared to it's industrial bigger bredren (less than > an inch offset in survery results). You'll need an Android device to use the > receiver, as it has no screen. > > If you want to roll your own RTK solution, then there's a Taiwanese company > that will sell you receivers and basestations for a few hundred dollars each. > https://www.polaris-gnss.com/ > > Disclaimer: I haven't used these yet. I have an upcoming mapping project this > summer then I might get some quality hands on time. > > >> Sent: Wednesday, May 06, 2020 >> From: ch...@wbmfg.com >> To: "AnimalFarm Microwave Users Group" >> Subject: Re: [AFMUG] Elevation question >> >> $600/year here in Utah... >> >> -Original Message- From: Mark Radabaugh >> Sent: Wednesday, May 6, 2020 9:57 AM >> To: AnimalFarm Microwave Users Group >> Subject: Re: [AFMUG] Elevation question >> >> Josh, >> >> In Ohio ODOT has a statewide RTK system set up that you can get free access >> too. It’s accessible over the internet so as long as your GPS receiver can >> connect to your phone to make the data connection to the state RTK system >> you can use the data. >> >> ODOT built if for their own use but make it available to the public to use. >> I believe in some locations they will set up a 900Mhz or similar repeater >> system to broadcast the data but most of the time they just use cellular >> data links. >> >> Mark >> >> > On May 6, 2020, at 11:37 AM, Brian Webster >> > wrote: >> > >> > https://en.wikipedia.org/wiki/Real-time_kinematic >> > >> > Real-time kinematic (RTK) positioning is a satellite navigation > technique >> > used to enhance the precision of position data derived from >> > satellite-based positioning systems (global navigation satellite > systems, >> > GNSS) such as GPS, GLONASS, Galileo, NavIC and BeiDou. It uses >> > measurements of the phase of the signal's carrier wave in addition to > the >> > information content of the signal and relies on a single reference > >> > station >> > or interpolated virtual station to provide real-time corrections, >> > providing up to centimetre-level accuracy.[1] With reference to GPS in >> > particular, the system is commonly referred to as carrier-phase >> > enhancement, or CPGPS.[2] It has applications in land survey, > >> > hydrographic >> > survey, and in unmanned aerial vehicle navigation. >> > >> > >> > >> > Thank you, >> > Brian Webster >> > www.wirelessmapping.com >> > >> > From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Brian Webster >> > Sent: Wednesday, May 6, 2020 11:33 AM >> > To: 'AnimalFarm Microwave Users Group' >> > Subject: Re: [AFMUG] Elevation question >> > >> > High end stuff. I never trust any consumer grade GPS device altitude >> > readings. I have seen them off by as much as 300 to 400 feet. High end > >> > GPS >> > devices rely on either a real time data link to ground reference > stations >> > or they post process the data back at the office. This is a process > where >> > you time sync your data with the ground reference stations, calculate > the >> > timing difference based on your location distance from the ground > control >> > points. The ground control points have a known coordinate and altitude. >> > They then compare the GPS readings at their point for those time > >> > reference >> > points you process against. They calculate the correction factor from > the >> > GPS against the known point, then also correct your data based on the >> > distance/time from the ground station and correct your data. For o
Re: [AFMUG] Elevation question
So what do the plans cost? -Original Message- From: fiber...@mail.com Sent: Wednesday, May 6, 2020 3:42 PM To: af@af.afmug.com Subject: Re: [AFMUG] Elevation question FYI, Trimble has an RTK receiver with a pay-as-you-go plan. The receiver (Trimble Catalyst DA-1) is $300-$400 and with that you select a plan according to your accuracy needs: 1 centimeter to 1 meter Plans are available in increments from hourly to yearly. The Catalyst is supposedly fairly good compared to it's industrial bigger bredren (less than an inch offset in survery results). You'll need an Android device to use the receiver, as it has no screen. If you want to roll your own RTK solution, then there's a Taiwanese company that will sell you receivers and basestations for a few hundred dollars each. https://www.polaris-gnss.com/ Disclaimer: I haven't used these yet. I have an upcoming mapping project this summer then I might get some quality hands on time. Sent: Wednesday, May 06, 2020 From: ch...@wbmfg.com To: "AnimalFarm Microwave Users Group" Subject: Re: [AFMUG] Elevation question $600/year here in Utah... -Original Message- From: Mark Radabaugh Sent: Wednesday, May 6, 2020 9:57 AM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question Josh, In Ohio ODOT has a statewide RTK system set up that you can get free access too. It’s accessible over the internet so as long as your GPS receiver can connect to your phone to make the data connection to the state RTK system you can use the data. ODOT built if for their own use but make it available to the public to use. I believe in some locations they will set up a 900Mhz or similar repeater system to broadcast the data but most of the time they just use cellular data links. Mark > On May 6, 2020, at 11:37 AM, Brian Webster > wrote: > > https://en.wikipedia.org/wiki/Real-time_kinematic > > Real-time kinematic (RTK) positioning is a satellite navigation > technique > used to enhance the precision of position data derived from > satellite-based positioning systems (global navigation satellite > systems, > GNSS) such as GPS, GLONASS, Galileo, NavIC and BeiDou. It uses > measurements of the phase of the signal's carrier wave in addition to > the > information content of the signal and relies on a single reference > station > or interpolated virtual station to provide real-time corrections, > providing up to centimetre-level accuracy.[1] With reference to GPS in > particular, the system is commonly referred to as carrier-phase > enhancement, or CPGPS.[2] It has applications in land survey, > hydrographic > survey, and in unmanned aerial vehicle navigation. > > > > Thank you, > Brian Webster > www.wirelessmapping.com > > From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Brian Webster > Sent: Wednesday, May 6, 2020 11:33 AM > To: 'AnimalFarm Microwave Users Group' > Subject: Re: [AFMUG] Elevation question > > High end stuff. I never trust any consumer grade GPS device altitude > readings. I have seen them off by as much as 300 to 400 feet. High end > GPS > devices rely on either a real time data link to ground reference > stations > or they post process the data back at the office. This is a process > where > you time sync your data with the ground reference stations, calculate > the > timing difference based on your location distance from the ground > control > points. The ground control points have a known coordinate and altitude. > They then compare the GPS readings at their point for those time > reference > points you process against. They calculate the correction factor from > the > GPS against the known point, then also correct your data based on the > distance/time from the ground station and correct your data. For older > GPS > units you sometimes had to occupy a point for a longer period of time > based on your distances from the control points. > > High end GPS units can also do RTK or real time kinematic data > collection. > This is done by either having a GPS base station controller that is real > time data linked to ground control stations or that the rover unit has > the > real time data connectivity. They do all the above processing steps in > real time, no post processing after the field work is done. Depending on > the equipment and setup, there are time requirements to have the > instrument on point to achieve the desired level of precision. Depending > on the type of work, faster systems are desired when you are doing > things > like having to stand in traffic to map every manhole and gas valve. > Other > uses that are slower can be fine if you can leave it on a tri-pod or > bi-pod for 30 seconds or longer. Slower systems are preferred by workers >
Re: [AFMUG] Elevation question
FYI, Trimble has an RTK receiver with a pay-as-you-go plan. The receiver (Trimble Catalyst DA-1) is $300-$400 and with that you select a plan according to your accuracy needs: 1 centimeter to 1 meter Plans are available in increments from hourly to yearly. The Catalyst is supposedly fairly good compared to it's industrial bigger bredren (less than an inch offset in survery results). You'll need an Android device to use the receiver, as it has no screen. If you want to roll your own RTK solution, then there's a Taiwanese company that will sell you receivers and basestations for a few hundred dollars each. https://www.polaris-gnss.com/ Disclaimer: I haven't used these yet. I have an upcoming mapping project this summer then I might get some quality hands on time. > Sent: Wednesday, May 06, 2020 > From: ch...@wbmfg.com > To: "AnimalFarm Microwave Users Group" > Subject: Re: [AFMUG] Elevation question > > $600/year here in Utah... > > -Original Message- > From: Mark Radabaugh > Sent: Wednesday, May 6, 2020 9:57 AM > To: AnimalFarm Microwave Users Group > Subject: Re: [AFMUG] Elevation question > > Josh, > > In Ohio ODOT has a statewide RTK system set up that you can get free access > too. It’s accessible over the internet so as long as your GPS receiver can > connect to your phone to make the data connection to the state RTK system > you can use the data. > > ODOT built if for their own use but make it available to the public to use. > I believe in some locations they will set up a 900Mhz or similar repeater > system to broadcast the data but most of the time they just use cellular > data links. > > Mark > > > On May 6, 2020, at 11:37 AM, Brian Webster > > wrote: > > > > https://en.wikipedia.org/wiki/Real-time_kinematic > > > > Real-time kinematic (RTK) positioning is a satellite navigation technique > > used to enhance the precision of position data derived from > > satellite-based positioning systems (global navigation satellite systems, > > GNSS) such as GPS, GLONASS, Galileo, NavIC and BeiDou. It uses > > measurements of the phase of the signal's carrier wave in addition to the > > information content of the signal and relies on a single reference station > > or interpolated virtual station to provide real-time corrections, > > providing up to centimetre-level accuracy.[1] With reference to GPS in > > particular, the system is commonly referred to as carrier-phase > > enhancement, or CPGPS.[2] It has applications in land survey, hydrographic > > survey, and in unmanned aerial vehicle navigation. > > > > > > > > Thank you, > > Brian Webster > > www.wirelessmapping.com > > > > From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Brian Webster > > Sent: Wednesday, May 6, 2020 11:33 AM > > To: 'AnimalFarm Microwave Users Group' > > Subject: Re: [AFMUG] Elevation question > > > > High end stuff. I never trust any consumer grade GPS device altitude > > readings. I have seen them off by as much as 300 to 400 feet. High end GPS > > devices rely on either a real time data link to ground reference stations > > or they post process the data back at the office. This is a process where > > you time sync your data with the ground reference stations, calculate the > > timing difference based on your location distance from the ground control > > points. The ground control points have a known coordinate and altitude. > > They then compare the GPS readings at their point for those time reference > > points you process against. They calculate the correction factor from the > > GPS against the known point, then also correct your data based on the > > distance/time from the ground station and correct your data. For older GPS > > units you sometimes had to occupy a point for a longer period of time > > based on your distances from the control points. > > > > High end GPS units can also do RTK or real time kinematic data collection. > > This is done by either having a GPS base station controller that is real > > time data linked to ground control stations or that the rover unit has the > > real time data connectivity. They do all the above processing steps in > > real time, no post processing after the field work is done. Depending on > > the equipment and setup, there are time requirements to have the > > instrument on point to achieve the desired level of precision. Depending > > on the type of work, faster systems are desired when you are doing things > > like having to stand in traffic to map every manhole and gas valve. Other > > uses that are slower can b
Re: [AFMUG] Elevation question
No, they say that your XYZ error at a specific time is such and such. You can post process the data and correct it or you can have the real time on line correction if your receiver is set up for it. The closer you are to one of their stations the better your correction will be. From: Josh Luthman Sent: Wednesday, May 6, 2020 1:14 PM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question So what information comes out of these ODOT garages, the geoid information? Their devices get GPS and with the x, y the ODOT gives them the z? Josh Luthman Office: 937-552-2340 Direct: 937-552-2343 1100 Wayne St Suite 1337 Troy, OH 45373 On Wed, May 6, 2020 at 2:17 PM Brian Webster wrote: Josh those reference stations are not broadcasting any differential correction data or anything related to the GPS system. They are physical reference stations that are precision surveyed and they have a GPS receiver for referencing the error of the GPS signals compared to their known physical location. Most are not on towers. Here is NY the bulk of the stations are located at various DOT offices/Garages. When you are linking to those for reference it’s a data IP connection, the only RF getting used is if you use your cell phone to connect to the internet. Any GPS base stations used for projects are usually Tripod mounted and data linked in to this reference system. They are broadcasting only a small footprint to the various GPS devices within a small radius. The portable base transmitters are usually either UHF low power (4 watts with a rubber duck antenna) or 900 MHz band. The 900 is more common because they don’t need a license. The UHF units are supposed to be licensed with the FCC. Thank you, Brian Webster www.wirelessmapping.com From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Josh Luthman Sent: Wednesday, May 6, 2020 1:42 PM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question Well that's pretty neat! I like how they jump right over our county. I know their garage has a big tower, always assumed it was for their internal communication - guess it looks more like that. http://www.dot.state.oh.us/Divisions/Engineering/CaddMapping/Aerial/Pages/VRSRTK.aspx Josh Luthman Office: 937-552-2340 Direct: 937-552-2343 1100 Wayne St Suite 1337 Troy, OH 45373 On Wed, May 6, 2020 at 11:58 AM Mark Radabaugh wrote: Josh, In Ohio ODOT has a statewide RTK system set up that you can get free access too. It’s accessible over the internet so as long as your GPS receiver can connect to your phone to make the data connection to the state RTK system you can use the data. ODOT built if for their own use but make it available to the public to use. I believe in some locations they will set up a 900Mhz or similar repeater system to broadcast the data but most of the time they just use cellular data links. Mark > On May 6, 2020, at 11:37 AM, Brian Webster wrote: > > https://en.wikipedia.org/wiki/Real-time_kinematic > > Real-time kinematic (RTK) positioning is a satellite navigation technique used to enhance the precision of position data derived from satellite-based positioning systems (global navigation satellite systems, GNSS) such as GPS, GLONASS, Galileo, NavIC and BeiDou. It uses measurements of the phase of the signal's carrier wave in addition to the information content of the signal and relies on a single reference station or interpolated virtual station to provide real-time corrections, providing up to centimetre-level accuracy.[1] With reference to GPS in particular, the system is commonly referred to as carrier-phase enhancement, or CPGPS.[2] It has applications in land survey, hydrographic survey, and in unmanned aerial vehicle navigation. > > > > Thank you, > Brian Webster > www.wirelessmapping.com > > From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Brian Webster > Sent: Wednesday, May 6, 2020 11:33 AM > To: 'AnimalFarm Microwave Users Group' > Subject: Re: [AFMUG] Elevation question > > High end stuff. I never trust any consumer grade GPS device altitude readings. I have seen them off by as much as 300 to 400 feet. High end GPS devices rely on either a real time data link to ground reference stations or they post process the data back at the office. This is a process where you time sync your data with the ground reference stations, calculate the timing difference based on your location distance from the ground control points. The ground control points have a known coordinate and altitude. They then compare the GPS readings at their point for those time reference points you process against. They calculate the correction factor from the GPS against the known point, then also correct your data based on the d
Re: [AFMUG] Elevation question
So what information comes out of these ODOT garages, the geoid information? Their devices get GPS and with the x, y the ODOT gives them the z? Josh Luthman Office: 937-552-2340 Direct: 937-552-2343 1100 Wayne St Suite 1337 Troy, OH 45373 On Wed, May 6, 2020 at 2:17 PM Brian Webster wrote: > Josh those reference stations are not broadcasting any differential > correction data or anything related to the GPS system. They are physical > reference stations that are precision surveyed and they have a GPS receiver > for referencing the error of the GPS signals compared to their known > physical location. Most are not on towers. Here is NY the bulk of the > stations are located at various DOT offices/Garages. When you are linking > to those for reference it’s a data IP connection, the only RF getting used > is if you use your cell phone to connect to the internet. > > > > Any GPS base stations used for projects are usually Tripod mounted and > data linked in to this reference system. They are broadcasting only a small > footprint to the various GPS devices within a small radius. The portable > base transmitters are usually either UHF low power (4 watts with a rubber > duck antenna) or 900 MHz band. The 900 is more common because they don’t > need a license. The UHF units are supposed to be licensed with the FCC. > > > > Thank you, > > Brian Webster > > www.wirelessmapping.com > > > > *From:* AF [mailto:af-boun...@af.afmug.com] *On Behalf Of *Josh Luthman > *Sent:* Wednesday, May 6, 2020 1:42 PM > *To:* AnimalFarm Microwave Users Group > *Subject:* Re: [AFMUG] Elevation question > > > > Well that's pretty neat! I like how they jump right over our county. I > know their garage has a big tower, always assumed it was for their internal > communication - guess it looks more like that. > > > > > http://www.dot.state.oh.us/Divisions/Engineering/CaddMapping/Aerial/Pages/VRSRTK.aspx > > > > > Josh Luthman > Office: 937-552-2340 > Direct: 937-552-2343 > 1100 Wayne St > Suite 1337 > Troy, OH 45373 > > > > > > On Wed, May 6, 2020 at 11:58 AM Mark Radabaugh wrote: > > Josh, > > In Ohio ODOT has a statewide RTK system set up that you can get free > access too. It’s accessible over the internet so as long as your GPS > receiver can connect to your phone to make the data connection to the state > RTK system you can use the data. > > ODOT built if for their own use but make it available to the public to > use. I believe in some locations they will set up a 900Mhz or similar > repeater system to broadcast the data but most of the time they just use > cellular data links. > > Mark > > > On May 6, 2020, at 11:37 AM, Brian Webster > wrote: > > > > https://en.wikipedia.org/wiki/Real-time_kinematic > > > > Real-time kinematic (RTK) positioning is a satellite navigation > technique used to enhance the precision of position data derived from > satellite-based positioning systems (global navigation satellite systems, > GNSS) such as GPS, GLONASS, Galileo, NavIC and BeiDou. It uses measurements > of the phase of the signal's carrier wave in addition to the information > content of the signal and relies on a single reference station or > interpolated virtual station to provide real-time corrections, providing up > to centimetre-level accuracy.[1] With reference to GPS in particular, the > system is commonly referred to as carrier-phase enhancement, or CPGPS.[2] > It has applications in land survey, hydrographic survey, and in unmanned > aerial vehicle navigation. > > > > > > > > Thank you, > > Brian Webster > > www.wirelessmapping.com > > > > From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Brian Webster > > Sent: Wednesday, May 6, 2020 11:33 AM > > To: 'AnimalFarm Microwave Users Group' > > Subject: Re: [AFMUG] Elevation question > > > > High end stuff. I never trust any consumer grade GPS device altitude > readings. I have seen them off by as much as 300 to 400 feet. High end GPS > devices rely on either a real time data link to ground reference stations > or they post process the data back at the office. This is a process where > you time sync your data with the ground reference stations, calculate the > timing difference based on your location distance from the ground control > points. The ground control points have a known coordinate and altitude. > They then compare the GPS readings at their point for those time reference > points you process against. They calculate the correction factor from the > GPS against the known point, then also correct your data based on the > distance/time from the ground station and correct your d
Re: [AFMUG] Elevation question
I see Trimble has a R1 GNSS receiver model that pairs via bluetooth with your phone/tablet. 1. Are they accurate enough to trust for surveying things like power poles/tower locations. 2. They’re $2500 retail, is there a cheaper option that still has “reasonable” accuracy? My experience with consumer grade GPS units is that they’re frequently inaccurate, sometimes wildly. Makes a difference when you’re near a property line. > On May 6, 2020, at 8:32 AM, Brian Webster wrote: > > High end stuff. I never trust any consumer grade GPS device altitude > readings. I have seen them off by as much as 300 to 400 feet. High end GPS > devices rely on either a real time data link to ground reference stations or > they post process the data back at the office. This is a process where you > time sync your data with the ground reference stations, calculate the timing > difference based on your location distance from the ground control points. > The ground control points have a known coordinate and altitude. They then > compare the GPS readings at their point for those time reference points you > process against. They calculate the correction factor from the GPS against > the known point, then also correct your data based on the distance/time from > the ground station and correct your data. For older GPS units you sometimes > had to occupy a point for a longer period of time based on your distances > from the control points. > > High end GPS units can also do RTK or real time kinematic data collection. > This is done by either having a GPS base station controller that is real time > data linked to ground control stations or that the rover unit has the real > time data connectivity. They do all the above processing steps in real time, > no post processing after the field work is done. Depending on the equipment > and setup, there are time requirements to have the instrument on point to > achieve the desired level of precision. Depending on the type of work, faster > systems are desired when you are doing things like having to stand in traffic > to map every manhole and gas valve. Other uses that are slower can be fine if > you can leave it on a tri-pod or bi-pod for 30 seconds or longer. Slower > systems are preferred by workers getting paid prevailing wages ;-) > > > Thank you, > Brian Webster > www.wirelessmapping.com <http://www.wirelessmapping.com/> > > From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Josh Luthman > Sent: Wednesday, May 6, 2020 11:17 AM > To: AnimalFarm Microwave Users Group > Subject: Re: [AFMUG] Elevation question > > >local Geoid data set loaded > > Is this something most GPS radios would have? Or just higher end ones? > > Josh Luthman > Office: 937-552-2340 > Direct: 937-552-2343 > 1100 Wayne St > Suite 1337 > Troy, OH 45373 > > > On Wed, May 6, 2020 at 10:36 AM Brian Webster <mailto:i...@wirelessmapping.com>> wrote: >> OK here is what I learned from my brother. >> >> You want to use the Geoid values, however you also want to make sure you >> have the Geoid model loaded in to your Trimble R8 GPS. (for those not paying >> attention that is a survey grade instrument with cm accuracy). >> The geoid numbers are tied to the map projection you are using and they are >> also tied to the GPS ground stations you are connected to 9necessary for the >> cm grade accuracy). The Ellipsoid values assume that the earth is >> perfectly/mathematically round. Geoid values correct for the fact that it is >> not perfectly round and the reason why your GPS needs the local Geoid data >> set loaded before you take readings. You do have the Geoid data for your >> area loaded don’t you? >> >> For radio mobile you will want to use the Geoid height converted to meters. >> >> Is there LIDAR data for the area in question? It might be easier just to use >> a value from that. Might also be nice to convert the LIDAR to a file format >> for Radio Mobile and use all that data (going to need a lot of disk space >> though). >> >> Thank you, >> Brian Webster >> www.wirelessmapping.com <http://www.wirelessmapping.com/> >> >> From: AF [mailto:af-boun...@af.afmug.com <mailto:af-boun...@af.afmug.com>] >> On Behalf Of ch...@wbmfg.com <mailto:ch...@wbmfg.com> >> Sent: Tuesday, May 5, 2020 2:12 PM >> To: af@af.afmug.com <mailto:af@af.afmug.com> >> Subject: [AFMUG] Elevation question >> >> I have a pretty good GPS receiver. Trimble R8 with a Yuma data collector. >> Normally we use it only for lats and longs. >> It is corrected in real time with a cellular data modem and
Re: [AFMUG] Elevation question
Well that's pretty neat! I like how they jump right over our county. I know their garage has a big tower, always assumed it was for their internal communication - guess it looks more like that. http://www.dot.state.oh.us/Divisions/Engineering/CaddMapping/Aerial/Pages/VRSRTK.aspx Josh Luthman Office: 937-552-2340 Direct: 937-552-2343 1100 Wayne St Suite 1337 Troy, OH 45373 On Wed, May 6, 2020 at 11:58 AM Mark Radabaugh wrote: > Josh, > > In Ohio ODOT has a statewide RTK system set up that you can get free > access too. It’s accessible over the internet so as long as your GPS > receiver can connect to your phone to make the data connection to the state > RTK system you can use the data. > > ODOT built if for their own use but make it available to the public to > use. I believe in some locations they will set up a 900Mhz or similar > repeater system to broadcast the data but most of the time they just use > cellular data links. > > Mark > > > On May 6, 2020, at 11:37 AM, Brian Webster > wrote: > > > > https://en.wikipedia.org/wiki/Real-time_kinematic > > > > Real-time kinematic (RTK) positioning is a satellite navigation > technique used to enhance the precision of position data derived from > satellite-based positioning systems (global navigation satellite systems, > GNSS) such as GPS, GLONASS, Galileo, NavIC and BeiDou. It uses measurements > of the phase of the signal's carrier wave in addition to the information > content of the signal and relies on a single reference station or > interpolated virtual station to provide real-time corrections, providing up > to centimetre-level accuracy.[1] With reference to GPS in particular, the > system is commonly referred to as carrier-phase enhancement, or CPGPS.[2] > It has applications in land survey, hydrographic survey, and in unmanned > aerial vehicle navigation. > > > > > > > > Thank you, > > Brian Webster > > www.wirelessmapping.com > > > > From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Brian Webster > > Sent: Wednesday, May 6, 2020 11:33 AM > > To: 'AnimalFarm Microwave Users Group' > > Subject: Re: [AFMUG] Elevation question > > > > High end stuff. I never trust any consumer grade GPS device altitude > readings. I have seen them off by as much as 300 to 400 feet. High end GPS > devices rely on either a real time data link to ground reference stations > or they post process the data back at the office. This is a process where > you time sync your data with the ground reference stations, calculate the > timing difference based on your location distance from the ground control > points. The ground control points have a known coordinate and altitude. > They then compare the GPS readings at their point for those time reference > points you process against. They calculate the correction factor from the > GPS against the known point, then also correct your data based on the > distance/time from the ground station and correct your data. For older GPS > units you sometimes had to occupy a point for a longer period of time based > on your distances from the control points. > > > > High end GPS units can also do RTK or real time kinematic data > collection. This is done by either having a GPS base station controller > that is real time data linked to ground control stations or that the rover > unit has the real time data connectivity. They do all the above processing > steps in real time, no post processing after the field work is done. > Depending on the equipment and setup, there are time requirements to have > the instrument on point to achieve the desired level of precision. > Depending on the type of work, faster systems are desired when you are > doing things like having to stand in traffic to map every manhole and gas > valve. Other uses that are slower can be fine if you can leave it on a > tri-pod or bi-pod for 30 seconds or longer. Slower systems are preferred by > workers getting paid prevailing wages ;-) > > > > > > Thank you, > > Brian Webster > > www.wirelessmapping.com > > > > From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Josh Luthman > > Sent: Wednesday, May 6, 2020 11:17 AM > > To: AnimalFarm Microwave Users Group > > Subject: Re: [AFMUG] Elevation question > > > >> local Geoid data set loaded > > > > Is this something most GPS radios would have? Or just higher end ones? > > > > > > Josh Luthman > > Office: 937-552-2340 > > Direct: 937-552-2343 > > 1100 Wayne St > > Suite 1337 > > Troy, OH 45373 > > > > > > On Wed, May 6, 2020 at 10:36 AM Brian Webster > wrote: > > OK here is what I learned from my br
Re: [AFMUG] Elevation question
I have seen the HARN acronym but never knew what it was. We will check into it. I just re upped our annual subscription to the VRS system... -Original Message- From: Brian Webster Sent: Wednesday, May 6, 2020 10:14 AM To: 'AnimalFarm Microwave Users Group' Subject: Re: [AFMUG] Elevation question Does the USGS have any HARN stations in your region? You could use those instead and they should be free. Might just require you to occupy the point longer because they might be farther away. Thank you, Brian Webster www.wirelessmapping.com -Original Message- From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of ch...@wbmfg.com Sent: Wednesday, May 6, 2020 12:10 PM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question $600/year here in Utah... -Original Message- From: Mark Radabaugh Sent: Wednesday, May 6, 2020 9:57 AM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question Josh, In Ohio ODOT has a statewide RTK system set up that you can get free access too. It’s accessible over the internet so as long as your GPS receiver can connect to your phone to make the data connection to the state RTK system you can use the data. ODOT built if for their own use but make it available to the public to use. I believe in some locations they will set up a 900Mhz or similar repeater system to broadcast the data but most of the time they just use cellular data links. Mark On May 6, 2020, at 11:37 AM, Brian Webster wrote: https://en.wikipedia.org/wiki/Real-time_kinematic Real-time kinematic (RTK) positioning is a satellite navigation technique used to enhance the precision of position data derived from satellite-based positioning systems (global navigation satellite systems, GNSS) such as GPS, GLONASS, Galileo, NavIC and BeiDou. It uses measurements of the phase of the signal's carrier wave in addition to the information content of the signal and relies on a single reference station or interpolated virtual station to provide real-time corrections, providing up to centimetre-level accuracy.[1] With reference to GPS in particular, the system is commonly referred to as carrier-phase enhancement, or CPGPS.[2] It has applications in land survey, hydrographic survey, and in unmanned aerial vehicle navigation. Thank you, Brian Webster www.wirelessmapping.com From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Brian Webster Sent: Wednesday, May 6, 2020 11:33 AM To: 'AnimalFarm Microwave Users Group' Subject: Re: [AFMUG] Elevation question High end stuff. I never trust any consumer grade GPS device altitude readings. I have seen them off by as much as 300 to 400 feet. High end GPS devices rely on either a real time data link to ground reference stations or they post process the data back at the office. This is a process where you time sync your data with the ground reference stations, calculate the timing difference based on your location distance from the ground control points. The ground control points have a known coordinate and altitude. They then compare the GPS readings at their point for those time reference points you process against. They calculate the correction factor from the GPS against the known point, then also correct your data based on the distance/time from the ground station and correct your data. For older GPS units you sometimes had to occupy a point for a longer period of time based on your distances from the control points. High end GPS units can also do RTK or real time kinematic data collection. This is done by either having a GPS base station controller that is real time data linked to ground control stations or that the rover unit has the real time data connectivity. They do all the above processing steps in real time, no post processing after the field work is done. Depending on the equipment and setup, there are time requirements to have the instrument on point to achieve the desired level of precision. Depending on the type of work, faster systems are desired when you are doing things like having to stand in traffic to map every manhole and gas valve. Other uses that are slower can be fine if you can leave it on a tri-pod or bi-pod for 30 seconds or longer. Slower systems are preferred by workers getting paid prevailing wages ;-) Thank you, Brian Webster www.wirelessmapping.com From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Josh Luthman Sent: Wednesday, May 6, 2020 11:17 AM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question local Geoid data set loaded Is this something most GPS radios would have? Or just higher end ones? Josh Luthman Office: 937-552-2340 Direct: 937-552-2343 1100 Wayne St Suite 1337 Troy, OH 45373 On Wed, May 6, 2020 at 10:36 AM Brian Webster wrote: OK here is what I learned from my brother. You want to use the Geoid values, however you also want to make sure you have the Geoid model loaded in to your Trimble R8 GPS. (for those not paying
Re: [AFMUG] Elevation question
Does the USGS have any HARN stations in your region? You could use those instead and they should be free. Might just require you to occupy the point longer because they might be farther away. Thank you, Brian Webster www.wirelessmapping.com -Original Message- From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of ch...@wbmfg.com Sent: Wednesday, May 6, 2020 12:10 PM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question $600/year here in Utah... -Original Message- From: Mark Radabaugh Sent: Wednesday, May 6, 2020 9:57 AM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question Josh, In Ohio ODOT has a statewide RTK system set up that you can get free access too. It’s accessible over the internet so as long as your GPS receiver can connect to your phone to make the data connection to the state RTK system you can use the data. ODOT built if for their own use but make it available to the public to use. I believe in some locations they will set up a 900Mhz or similar repeater system to broadcast the data but most of the time they just use cellular data links. Mark > On May 6, 2020, at 11:37 AM, Brian Webster > wrote: > > https://en.wikipedia.org/wiki/Real-time_kinematic > > Real-time kinematic (RTK) positioning is a satellite navigation technique > used to enhance the precision of position data derived from > satellite-based positioning systems (global navigation satellite systems, > GNSS) such as GPS, GLONASS, Galileo, NavIC and BeiDou. It uses > measurements of the phase of the signal's carrier wave in addition to the > information content of the signal and relies on a single reference station > or interpolated virtual station to provide real-time corrections, > providing up to centimetre-level accuracy.[1] With reference to GPS in > particular, the system is commonly referred to as carrier-phase > enhancement, or CPGPS.[2] It has applications in land survey, hydrographic > survey, and in unmanned aerial vehicle navigation. > > > > Thank you, > Brian Webster > www.wirelessmapping.com > > From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Brian Webster > Sent: Wednesday, May 6, 2020 11:33 AM > To: 'AnimalFarm Microwave Users Group' > Subject: Re: [AFMUG] Elevation question > > High end stuff. I never trust any consumer grade GPS device altitude > readings. I have seen them off by as much as 300 to 400 feet. High end GPS > devices rely on either a real time data link to ground reference stations > or they post process the data back at the office. This is a process where > you time sync your data with the ground reference stations, calculate the > timing difference based on your location distance from the ground control > points. The ground control points have a known coordinate and altitude. > They then compare the GPS readings at their point for those time reference > points you process against. They calculate the correction factor from the > GPS against the known point, then also correct your data based on the > distance/time from the ground station and correct your data. For older GPS > units you sometimes had to occupy a point for a longer period of time > based on your distances from the control points. > > High end GPS units can also do RTK or real time kinematic data collection. > This is done by either having a GPS base station controller that is real > time data linked to ground control stations or that the rover unit has the > real time data connectivity. They do all the above processing steps in > real time, no post processing after the field work is done. Depending on > the equipment and setup, there are time requirements to have the > instrument on point to achieve the desired level of precision. Depending > on the type of work, faster systems are desired when you are doing things > like having to stand in traffic to map every manhole and gas valve. Other > uses that are slower can be fine if you can leave it on a tri-pod or > bi-pod for 30 seconds or longer. Slower systems are preferred by workers > getting paid prevailing wages ;-) > > > Thank you, > Brian Webster > www.wirelessmapping.com > > From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Josh Luthman > Sent: Wednesday, May 6, 2020 11:17 AM > To: AnimalFarm Microwave Users Group > Subject: Re: [AFMUG] Elevation question > >> local Geoid data set loaded > > Is this something most GPS radios would have? Or just higher end ones? > > > Josh Luthman > Office: 937-552-2340 > Direct: 937-552-2343 > 1100 Wayne St > Suite 1337 > Troy, OH 45373 > > > On Wed, May 6, 2020 at 10:36 AM Brian Webster > wrote: > OK here is what I learned from my brother. > > You want to use the G
Re: [AFMUG] Elevation question
$600/year here in Utah... -Original Message- From: Mark Radabaugh Sent: Wednesday, May 6, 2020 9:57 AM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question Josh, In Ohio ODOT has a statewide RTK system set up that you can get free access too. It’s accessible over the internet so as long as your GPS receiver can connect to your phone to make the data connection to the state RTK system you can use the data. ODOT built if for their own use but make it available to the public to use. I believe in some locations they will set up a 900Mhz or similar repeater system to broadcast the data but most of the time they just use cellular data links. Mark On May 6, 2020, at 11:37 AM, Brian Webster wrote: https://en.wikipedia.org/wiki/Real-time_kinematic Real-time kinematic (RTK) positioning is a satellite navigation technique used to enhance the precision of position data derived from satellite-based positioning systems (global navigation satellite systems, GNSS) such as GPS, GLONASS, Galileo, NavIC and BeiDou. It uses measurements of the phase of the signal's carrier wave in addition to the information content of the signal and relies on a single reference station or interpolated virtual station to provide real-time corrections, providing up to centimetre-level accuracy.[1] With reference to GPS in particular, the system is commonly referred to as carrier-phase enhancement, or CPGPS.[2] It has applications in land survey, hydrographic survey, and in unmanned aerial vehicle navigation. Thank you, Brian Webster www.wirelessmapping.com From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Brian Webster Sent: Wednesday, May 6, 2020 11:33 AM To: 'AnimalFarm Microwave Users Group' Subject: Re: [AFMUG] Elevation question High end stuff. I never trust any consumer grade GPS device altitude readings. I have seen them off by as much as 300 to 400 feet. High end GPS devices rely on either a real time data link to ground reference stations or they post process the data back at the office. This is a process where you time sync your data with the ground reference stations, calculate the timing difference based on your location distance from the ground control points. The ground control points have a known coordinate and altitude. They then compare the GPS readings at their point for those time reference points you process against. They calculate the correction factor from the GPS against the known point, then also correct your data based on the distance/time from the ground station and correct your data. For older GPS units you sometimes had to occupy a point for a longer period of time based on your distances from the control points. High end GPS units can also do RTK or real time kinematic data collection. This is done by either having a GPS base station controller that is real time data linked to ground control stations or that the rover unit has the real time data connectivity. They do all the above processing steps in real time, no post processing after the field work is done. Depending on the equipment and setup, there are time requirements to have the instrument on point to achieve the desired level of precision. Depending on the type of work, faster systems are desired when you are doing things like having to stand in traffic to map every manhole and gas valve. Other uses that are slower can be fine if you can leave it on a tri-pod or bi-pod for 30 seconds or longer. Slower systems are preferred by workers getting paid prevailing wages ;-) Thank you, Brian Webster www.wirelessmapping.com From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Josh Luthman Sent: Wednesday, May 6, 2020 11:17 AM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question local Geoid data set loaded Is this something most GPS radios would have? Or just higher end ones? Josh Luthman Office: 937-552-2340 Direct: 937-552-2343 1100 Wayne St Suite 1337 Troy, OH 45373 On Wed, May 6, 2020 at 10:36 AM Brian Webster wrote: OK here is what I learned from my brother. You want to use the Geoid values, however you also want to make sure you have the Geoid model loaded in to your Trimble R8 GPS. (for those not paying attention that is a survey grade instrument with cm accuracy). The geoid numbers are tied to the map projection you are using and they are also tied to the GPS ground stations you are connected to 9necessary for the cm grade accuracy). The Ellipsoid values assume that the earth is perfectly/mathematically round. Geoid values correct for the fact that it is not perfectly round and the reason why your GPS needs the local Geoid data set loaded before you take readings. You do have the Geoid data for your area loaded don’t you? For radio mobile you will want to use the Geoid height converted to meters. Is there LIDAR data for the area in question? It might be easier just to use a value from that. Might also
Re: [AFMUG] Elevation question
Most states have this now. For ongoing larger highway projects I have seen the local transmitters set up by the contractors. Thank you, Brian Webster www.wirelessmapping.com -Original Message- From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Mark Radabaugh Sent: Wednesday, May 6, 2020 11:58 AM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question Josh, In Ohio ODOT has a statewide RTK system set up that you can get free access too. It’s accessible over the internet so as long as your GPS receiver can connect to your phone to make the data connection to the state RTK system you can use the data. ODOT built if for their own use but make it available to the public to use. I believe in some locations they will set up a 900Mhz or similar repeater system to broadcast the data but most of the time they just use cellular data links. Mark > On May 6, 2020, at 11:37 AM, Brian Webster wrote: > > https://en.wikipedia.org/wiki/Real-time_kinematic > > Real-time kinematic (RTK) positioning is a satellite navigation technique > used to enhance the precision of position data derived from satellite-based > positioning systems (global navigation satellite systems, GNSS) such as GPS, > GLONASS, Galileo, NavIC and BeiDou. It uses measurements of the phase of the > signal's carrier wave in addition to the information content of the signal > and relies on a single reference station or interpolated virtual station to > provide real-time corrections, providing up to centimetre-level accuracy.[1] > With reference to GPS in particular, the system is commonly referred to as > carrier-phase enhancement, or CPGPS.[2] It has applications in land survey, > hydrographic survey, and in unmanned aerial vehicle navigation. > > > > Thank you, > Brian Webster > www.wirelessmapping.com > > From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Brian Webster > Sent: Wednesday, May 6, 2020 11:33 AM > To: 'AnimalFarm Microwave Users Group' > Subject: Re: [AFMUG] Elevation question > > High end stuff. I never trust any consumer grade GPS device altitude > readings. I have seen them off by as much as 300 to 400 feet. High end GPS > devices rely on either a real time data link to ground reference stations or > they post process the data back at the office. This is a process where you > time sync your data with the ground reference stations, calculate the timing > difference based on your location distance from the ground control points. > The ground control points have a known coordinate and altitude. They then > compare the GPS readings at their point for those time reference points you > process against. They calculate the correction factor from the GPS against > the known point, then also correct your data based on the distance/time from > the ground station and correct your data. For older GPS units you sometimes > had to occupy a point for a longer period of time based on your distances > from the control points. > > High end GPS units can also do RTK or real time kinematic data collection. > This is done by either having a GPS base station controller that is real time > data linked to ground control stations or that the rover unit has the real > time data connectivity. They do all the above processing steps in real time, > no post processing after the field work is done. Depending on the equipment > and setup, there are time requirements to have the instrument on point to > achieve the desired level of precision. Depending on the type of work, faster > systems are desired when you are doing things like having to stand in traffic > to map every manhole and gas valve. Other uses that are slower can be fine if > you can leave it on a tri-pod or bi-pod for 30 seconds or longer. Slower > systems are preferred by workers getting paid prevailing wages ;-) > > > Thank you, > Brian Webster > www.wirelessmapping.com > > From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Josh Luthman > Sent: Wednesday, May 6, 2020 11:17 AM > To: AnimalFarm Microwave Users Group > Subject: Re: [AFMUG] Elevation question > >> local Geoid data set loaded > > Is this something most GPS radios would have? Or just higher end ones? > > > Josh Luthman > Office: 937-552-2340 > Direct: 937-552-2343 > 1100 Wayne St > Suite 1337 > Troy, OH 45373 > > > On Wed, May 6, 2020 at 10:36 AM Brian Webster > wrote: > OK here is what I learned from my brother. > > You want to use the Geoid values, however you also want to make sure you have > the Geoid model loaded in to your Trimble R8 GPS. (for those not paying > attention that is a survey grade instrument with cm accuracy). > The geoid numbers are tied to the map pro
Re: [AFMUG] Elevation question
Josh, In Ohio ODOT has a statewide RTK system set up that you can get free access too. It’s accessible over the internet so as long as your GPS receiver can connect to your phone to make the data connection to the state RTK system you can use the data. ODOT built if for their own use but make it available to the public to use. I believe in some locations they will set up a 900Mhz or similar repeater system to broadcast the data but most of the time they just use cellular data links. Mark > On May 6, 2020, at 11:37 AM, Brian Webster wrote: > > https://en.wikipedia.org/wiki/Real-time_kinematic > > Real-time kinematic (RTK) positioning is a satellite navigation technique > used to enhance the precision of position data derived from satellite-based > positioning systems (global navigation satellite systems, GNSS) such as GPS, > GLONASS, Galileo, NavIC and BeiDou. It uses measurements of the phase of the > signal's carrier wave in addition to the information content of the signal > and relies on a single reference station or interpolated virtual station to > provide real-time corrections, providing up to centimetre-level accuracy.[1] > With reference to GPS in particular, the system is commonly referred to as > carrier-phase enhancement, or CPGPS.[2] It has applications in land survey, > hydrographic survey, and in unmanned aerial vehicle navigation. > > > > Thank you, > Brian Webster > www.wirelessmapping.com > > From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Brian Webster > Sent: Wednesday, May 6, 2020 11:33 AM > To: 'AnimalFarm Microwave Users Group' > Subject: Re: [AFMUG] Elevation question > > High end stuff. I never trust any consumer grade GPS device altitude > readings. I have seen them off by as much as 300 to 400 feet. High end GPS > devices rely on either a real time data link to ground reference stations or > they post process the data back at the office. This is a process where you > time sync your data with the ground reference stations, calculate the timing > difference based on your location distance from the ground control points. > The ground control points have a known coordinate and altitude. They then > compare the GPS readings at their point for those time reference points you > process against. They calculate the correction factor from the GPS against > the known point, then also correct your data based on the distance/time from > the ground station and correct your data. For older GPS units you sometimes > had to occupy a point for a longer period of time based on your distances > from the control points. > > High end GPS units can also do RTK or real time kinematic data collection. > This is done by either having a GPS base station controller that is real time > data linked to ground control stations or that the rover unit has the real > time data connectivity. They do all the above processing steps in real time, > no post processing after the field work is done. Depending on the equipment > and setup, there are time requirements to have the instrument on point to > achieve the desired level of precision. Depending on the type of work, faster > systems are desired when you are doing things like having to stand in traffic > to map every manhole and gas valve. Other uses that are slower can be fine if > you can leave it on a tri-pod or bi-pod for 30 seconds or longer. Slower > systems are preferred by workers getting paid prevailing wages ;-) > > > Thank you, > Brian Webster > www.wirelessmapping.com > > From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Josh Luthman > Sent: Wednesday, May 6, 2020 11:17 AM > To: AnimalFarm Microwave Users Group > Subject: Re: [AFMUG] Elevation question > >> local Geoid data set loaded > > Is this something most GPS radios would have? Or just higher end ones? > > > Josh Luthman > Office: 937-552-2340 > Direct: 937-552-2343 > 1100 Wayne St > Suite 1337 > Troy, OH 45373 > > > On Wed, May 6, 2020 at 10:36 AM Brian Webster > wrote: > OK here is what I learned from my brother. > > You want to use the Geoid values, however you also want to make sure you have > the Geoid model loaded in to your Trimble R8 GPS. (for those not paying > attention that is a survey grade instrument with cm accuracy). > The geoid numbers are tied to the map projection you are using and they are > also tied to the GPS ground stations you are connected to 9necessary for the > cm grade accuracy). The Ellipsoid values assume that the earth is > perfectly/mathematically round. Geoid values correct for the fact that it is > not perfectly round and the reason why your GPS needs the local Geoid data > set loaded before you take readings. You do ha
Re: [AFMUG] Elevation question
RTK is used in precision agriculture. There is usually some sort of local transmitter GPS base station combination that is linked or surveyed like a ground control station. They then broadcast over RF (usually 900 MHz) a data correction signal locally that any device that has a differential correction receiver attached to the GPS system. These differential transmitter stations have a limited range and effectiveness for the mobile GPS units. Thank you, Brian Webster www.wirelessmapping.com -Original Message- From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Brian Webster Sent: Wednesday, May 6, 2020 11:38 AM To: 'AnimalFarm Microwave Users Group' Subject: Re: [AFMUG] Elevation question https://en.wikipedia.org/wiki/Real-time_kinematic Real-time kinematic (RTK) positioning is a satellite navigation technique used to enhance the precision of position data derived from satellite-based positioning systems (global navigation satellite systems, GNSS) such as GPS, GLONASS, Galileo, NavIC and BeiDou. It uses measurements of the phase of the signal's carrier wave in addition to the information content of the signal and relies on a single reference station or interpolated virtual station to provide real-time corrections, providing up to centimetre-level accuracy.[1] With reference to GPS in particular, the system is commonly referred to as carrier-phase enhancement, or CPGPS.[2] It has applications in land survey, hydrographic survey, and in unmanned aerial vehicle navigation. Thank you, Brian Webster www.wirelessmapping.com From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Brian Webster Sent: Wednesday, May 6, 2020 11:33 AM To: 'AnimalFarm Microwave Users Group' Subject: Re: [AFMUG] Elevation question High end stuff. I never trust any consumer grade GPS device altitude readings. I have seen them off by as much as 300 to 400 feet. High end GPS devices rely on either a real time data link to ground reference stations or they post process the data back at the office. This is a process where you time sync your data with the ground reference stations, calculate the timing difference based on your location distance from the ground control points. The ground control points have a known coordinate and altitude. They then compare the GPS readings at their point for those time reference points you process against. They calculate the correction factor from the GPS against the known point, then also correct your data based on the distance/time from the ground station and correct your data. For older GPS units you sometimes had to occupy a point for a longer period of time based on your distances from the control points. High end GPS units can also do RTK or real time kinematic data collection. This is done by either having a GPS base station controller that is real time data linked to ground control stations or that the rover unit has the real time data connectivity. They do all the above processing steps in real time, no post processing after the field work is done. Depending on the equipment and setup, there are time requirements to have the instrument on point to achieve the desired level of precision. Depending on the type of work, faster systems are desired when you are doing things like having to stand in traffic to map every manhole and gas valve. Other uses that are slower can be fine if you can leave it on a tri-pod or bi-pod for 30 seconds or longer. Slower systems are preferred by workers getting paid prevailing wages ;-) Thank you, Brian Webster www.wirelessmapping.com From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Josh Luthman Sent: Wednesday, May 6, 2020 11:17 AM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question >local Geoid data set loaded Is this something most GPS radios would have? Or just higher end ones? Josh Luthman Office: 937-552-2340 Direct: 937-552-2343 1100 Wayne St Suite 1337 Troy, OH 45373 On Wed, May 6, 2020 at 10:36 AM Brian Webster wrote: OK here is what I learned from my brother. You want to use the Geoid values, however you also want to make sure you have the Geoid model loaded in to your Trimble R8 GPS. (for those not paying attention that is a survey grade instrument with cm accuracy). The geoid numbers are tied to the map projection you are using and they are also tied to the GPS ground stations you are connected to 9necessary for the cm grade accuracy). The Ellipsoid values assume that the earth is perfectly/mathematically round. Geoid values correct for the fact that it is not perfectly round and the reason why your GPS needs the local Geoid data set loaded before you take readings. You do have the Geoid data for your area loaded don’t you? For radio mobile you will want to use the Geoid height converted to meters. Is there LIDAR data for the area in question? It might be easier just to use a value from that. Might also be nice to convert the LIDAR to a file for
Re: [AFMUG] Elevation question
https://en.wikipedia.org/wiki/Real-time_kinematic Real-time kinematic (RTK) positioning is a satellite navigation technique used to enhance the precision of position data derived from satellite-based positioning systems (global navigation satellite systems, GNSS) such as GPS, GLONASS, Galileo, NavIC and BeiDou. It uses measurements of the phase of the signal's carrier wave in addition to the information content of the signal and relies on a single reference station or interpolated virtual station to provide real-time corrections, providing up to centimetre-level accuracy.[1] With reference to GPS in particular, the system is commonly referred to as carrier-phase enhancement, or CPGPS.[2] It has applications in land survey, hydrographic survey, and in unmanned aerial vehicle navigation. Thank you, Brian Webster www.wirelessmapping.com From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Brian Webster Sent: Wednesday, May 6, 2020 11:33 AM To: 'AnimalFarm Microwave Users Group' Subject: Re: [AFMUG] Elevation question High end stuff. I never trust any consumer grade GPS device altitude readings. I have seen them off by as much as 300 to 400 feet. High end GPS devices rely on either a real time data link to ground reference stations or they post process the data back at the office. This is a process where you time sync your data with the ground reference stations, calculate the timing difference based on your location distance from the ground control points. The ground control points have a known coordinate and altitude. They then compare the GPS readings at their point for those time reference points you process against. They calculate the correction factor from the GPS against the known point, then also correct your data based on the distance/time from the ground station and correct your data. For older GPS units you sometimes had to occupy a point for a longer period of time based on your distances from the control points. High end GPS units can also do RTK or real time kinematic data collection. This is done by either having a GPS base station controller that is real time data linked to ground control stations or that the rover unit has the real time data connectivity. They do all the above processing steps in real time, no post processing after the field work is done. Depending on the equipment and setup, there are time requirements to have the instrument on point to achieve the desired level of precision. Depending on the type of work, faster systems are desired when you are doing things like having to stand in traffic to map every manhole and gas valve. Other uses that are slower can be fine if you can leave it on a tri-pod or bi-pod for 30 seconds or longer. Slower systems are preferred by workers getting paid prevailing wages ;-) Thank you, Brian Webster www.wirelessmapping.com From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Josh Luthman Sent: Wednesday, May 6, 2020 11:17 AM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question >local Geoid data set loaded Is this something most GPS radios would have? Or just higher end ones? Josh Luthman Office: 937-552-2340 Direct: 937-552-2343 1100 Wayne St Suite 1337 Troy, OH 45373 On Wed, May 6, 2020 at 10:36 AM Brian Webster wrote: OK here is what I learned from my brother. You want to use the Geoid values, however you also want to make sure you have the Geoid model loaded in to your Trimble R8 GPS. (for those not paying attention that is a survey grade instrument with cm accuracy). The geoid numbers are tied to the map projection you are using and they are also tied to the GPS ground stations you are connected to 9necessary for the cm grade accuracy). The Ellipsoid values assume that the earth is perfectly/mathematically round. Geoid values correct for the fact that it is not perfectly round and the reason why your GPS needs the local Geoid data set loaded before you take readings. You do have the Geoid data for your area loaded don’t you? For radio mobile you will want to use the Geoid height converted to meters. Is there LIDAR data for the area in question? It might be easier just to use a value from that. Might also be nice to convert the LIDAR to a file format for Radio Mobile and use all that data (going to need a lot of disk space though). Thank you, Brian Webster www.wirelessmapping.com From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of ch...@wbmfg.com Sent: Tuesday, May 5, 2020 2:12 PM To: af@af.afmug.com Subject: [AFMUG] Elevation question I have a pretty good GPS receiver. Trimble R8 with a Yuma data collector. Normally we use it only for lats and longs. It is corrected in real time with a cellular data modem and a RTK/VRS ground station network. Yesterday we did a shot from a hill that did not exist when shuttle radar data was taken. It was way off in elevation. So we took a shot from our parking lot and compared it with what we th
Re: [AFMUG] Elevation question
Off the top of my head the GEOID set is probably not too large. Seems like when I was looking at my R8 unit there were only a handful of geoid set files for the country. They get loaded in to the data collector unit and those usually don’t have huge amounts of storage. Thank you, Brian Webster www.wirelessmapping.com From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of ch...@wbmfg.com Sent: Wednesday, May 6, 2020 11:29 AM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question I think that you have to be using some kind of geoid to get any kind of decent elevation that is related to mean sea level. I presume they all just pick one and use it. I wonder how many data points are in a geoid. From: Josh Luthman Sent: Wednesday, May 6, 2020 9:17 AM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question >local Geoid data set loaded Is this something most GPS radios would have? Or just higher end ones? Josh Luthman Office: 937-552-2340 Direct: 937-552-2343 1100 Wayne St Suite 1337 Troy, OH 45373 On Wed, May 6, 2020 at 10:36 AM Brian Webster wrote: OK here is what I learned from my brother. You want to use the Geoid values, however you also want to make sure you have the Geoid model loaded in to your Trimble R8 GPS. (for those not paying attention that is a survey grade instrument with cm accuracy). The geoid numbers are tied to the map projection you are using and they are also tied to the GPS ground stations you are connected to 9necessary for the cm grade accuracy). The Ellipsoid values assume that the earth is perfectly/mathematically round. Geoid values correct for the fact that it is not perfectly round and the reason why your GPS needs the local Geoid data set loaded before you take readings. You do have the Geoid data for your area loaded don’t you? For radio mobile you will want to use the Geoid height converted to meters. Is there LIDAR data for the area in question? It might be easier just to use a value from that. Might also be nice to convert the LIDAR to a file format for Radio Mobile and use all that data (going to need a lot of disk space though). Thank you, Brian Webster www.wirelessmapping.com From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of ch...@wbmfg.com Sent: Tuesday, May 5, 2020 2:12 PM To: af@af.afmug.com Subject: [AFMUG] Elevation question I have a pretty good GPS receiver. Trimble R8 with a Yuma data collector. Normally we use it only for lats and longs. It is corrected in real time with a cellular data modem and a RTK/VRS ground station network. Yesterday we did a shot from a hill that did not exist when shuttle radar data was taken. It was way off in elevation. So we took a shot from our parking lot and compared it with what we think we know to be the altitude as well as our cell phones and google earth. Turns out the R8 has an ellipsoid height as well as another height associated with the northing and easting values. The second one seems to be more in line with what I was expecting. The local dealer sent me a drawing showing this. (attached) So now I am super confused. Not sure what number to use when working with Radio Mobile. Do I add the geoid height to the ellipsoid height? Was hoping Brian Webster may know or others may know. Googling google earth elevation talks about different versions of geoid. Not sure if their elevations are geoid elevations or not. So, rather than dig into it any more I am taking the lazy approach and posting the question here. -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com _ -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
Re: [AFMUG] Elevation question
High end stuff. I never trust any consumer grade GPS device altitude readings. I have seen them off by as much as 300 to 400 feet. High end GPS devices rely on either a real time data link to ground reference stations or they post process the data back at the office. This is a process where you time sync your data with the ground reference stations, calculate the timing difference based on your location distance from the ground control points. The ground control points have a known coordinate and altitude. They then compare the GPS readings at their point for those time reference points you process against. They calculate the correction factor from the GPS against the known point, then also correct your data based on the distance/time from the ground station and correct your data. For older GPS units you sometimes had to occupy a point for a longer period of time based on your distances from the control points. High end GPS units can also do RTK or real time kinematic data collection. This is done by either having a GPS base station controller that is real time data linked to ground control stations or that the rover unit has the real time data connectivity. They do all the above processing steps in real time, no post processing after the field work is done. Depending on the equipment and setup, there are time requirements to have the instrument on point to achieve the desired level of precision. Depending on the type of work, faster systems are desired when you are doing things like having to stand in traffic to map every manhole and gas valve. Other uses that are slower can be fine if you can leave it on a tri-pod or bi-pod for 30 seconds or longer. Slower systems are preferred by workers getting paid prevailing wages ;-) Thank you, Brian Webster www.wirelessmapping.com From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of Josh Luthman Sent: Wednesday, May 6, 2020 11:17 AM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question >local Geoid data set loaded Is this something most GPS radios would have? Or just higher end ones? Josh Luthman Office: 937-552-2340 Direct: 937-552-2343 1100 Wayne St Suite 1337 Troy, OH 45373 On Wed, May 6, 2020 at 10:36 AM Brian Webster wrote: OK here is what I learned from my brother. You want to use the Geoid values, however you also want to make sure you have the Geoid model loaded in to your Trimble R8 GPS. (for those not paying attention that is a survey grade instrument with cm accuracy). The geoid numbers are tied to the map projection you are using and they are also tied to the GPS ground stations you are connected to 9necessary for the cm grade accuracy). The Ellipsoid values assume that the earth is perfectly/mathematically round. Geoid values correct for the fact that it is not perfectly round and the reason why your GPS needs the local Geoid data set loaded before you take readings. You do have the Geoid data for your area loaded don’t you? For radio mobile you will want to use the Geoid height converted to meters. Is there LIDAR data for the area in question? It might be easier just to use a value from that. Might also be nice to convert the LIDAR to a file format for Radio Mobile and use all that data (going to need a lot of disk space though). Thank you, Brian Webster www.wirelessmapping.com From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of ch...@wbmfg.com Sent: Tuesday, May 5, 2020 2:12 PM To: af@af.afmug.com Subject: [AFMUG] Elevation question I have a pretty good GPS receiver. Trimble R8 with a Yuma data collector. Normally we use it only for lats and longs. It is corrected in real time with a cellular data modem and a RTK/VRS ground station network. Yesterday we did a shot from a hill that did not exist when shuttle radar data was taken. It was way off in elevation. So we took a shot from our parking lot and compared it with what we think we know to be the altitude as well as our cell phones and google earth. Turns out the R8 has an ellipsoid height as well as another height associated with the northing and easting values. The second one seems to be more in line with what I was expecting. The local dealer sent me a drawing showing this. (attached) So now I am super confused. Not sure what number to use when working with Radio Mobile. Do I add the geoid height to the ellipsoid height? Was hoping Brian Webster may know or others may know. Googling google earth elevation talks about different versions of geoid. Not sure if their elevations are geoid elevations or not. So, rather than dig into it any more I am taking the lazy approach and posting the question here. -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
Re: [AFMUG] Elevation question
I think that you have to be using some kind of geoid to get any kind of decent elevation that is related to mean sea level. I presume they all just pick one and use it. I wonder how many data points are in a geoid. From: Josh Luthman Sent: Wednesday, May 6, 2020 9:17 AM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question >local Geoid data set loaded Is this something most GPS radios would have? Or just higher end ones? Josh Luthman Office: 937-552-2340 Direct: 937-552-2343 1100 Wayne St Suite 1337 Troy, OH 45373 On Wed, May 6, 2020 at 10:36 AM Brian Webster wrote: OK here is what I learned from my brother. You want to use the Geoid values, however you also want to make sure you have the Geoid model loaded in to your Trimble R8 GPS. (for those not paying attention that is a survey grade instrument with cm accuracy). The geoid numbers are tied to the map projection you are using and they are also tied to the GPS ground stations you are connected to 9necessary for the cm grade accuracy). The Ellipsoid values assume that the earth is perfectly/mathematically round. Geoid values correct for the fact that it is not perfectly round and the reason why your GPS needs the local Geoid data set loaded before you take readings. You do have the Geoid data for your area loaded don’t you? For radio mobile you will want to use the Geoid height converted to meters. Is there LIDAR data for the area in question? It might be easier just to use a value from that. Might also be nice to convert the LIDAR to a file format for Radio Mobile and use all that data (going to need a lot of disk space though). Thank you, Brian Webster www.wirelessmapping.com From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of ch...@wbmfg.com Sent: Tuesday, May 5, 2020 2:12 PM To: af@af.afmug.com Subject: [AFMUG] Elevation question I have a pretty good GPS receiver. Trimble R8 with a Yuma data collector. Normally we use it only for lats and longs. It is corrected in real time with a cellular data modem and a RTK/VRS ground station network. Yesterday we did a shot from a hill that did not exist when shuttle radar data was taken. It was way off in elevation. So we took a shot from our parking lot and compared it with what we think we know to be the altitude as well as our cell phones and google earth. Turns out the R8 has an ellipsoid height as well as another height associated with the northing and easting values. The second one seems to be more in line with what I was expecting. The local dealer sent me a drawing showing this. (attached) So now I am super confused. Not sure what number to use when working with Radio Mobile. Do I add the geoid height to the ellipsoid height? Was hoping Brian Webster may know or others may know. Googling google earth elevation talks about different versions of geoid. Not sure if their elevations are geoid elevations or not. So, rather than dig into it any more I am taking the lazy approach and posting the question here. -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
Re: [AFMUG] Elevation question
>local Geoid data set loaded Is this something most GPS radios would have? Or just higher end ones? Josh Luthman Office: 937-552-2340 Direct: 937-552-2343 1100 Wayne St Suite 1337 Troy, OH 45373 On Wed, May 6, 2020 at 10:36 AM Brian Webster wrote: > OK here is what I learned from my brother. > > > > You want to use the Geoid values, however you also want to make sure you > have the Geoid model loaded in to your Trimble R8 GPS. (for those not > paying attention that is a survey grade instrument with cm accuracy). > > The geoid numbers are tied to the map projection you are using and they > are also tied to the GPS ground stations you are connected to 9necessary > for the cm grade accuracy). The Ellipsoid values assume that the earth is > perfectly/mathematically round. Geoid values correct for the fact that it > is not perfectly round and the reason why your GPS needs the local Geoid > data set loaded before you take readings. You do have the Geoid data for > your area loaded don’t you? > > > > For radio mobile you will want to use the Geoid height converted to meters. > > > > Is there LIDAR data for the area in question? It might be easier just to > use a value from that. Might also be nice to convert the LIDAR to a file > format for Radio Mobile and use all that data (going to need a lot of disk > space though). > > > > Thank you, > > Brian Webster > > www.wirelessmapping.com > > > > *From:* AF [mailto:af-boun...@af.afmug.com] *On Behalf Of *ch...@wbmfg.com > *Sent:* Tuesday, May 5, 2020 2:12 PM > *To:* af@af.afmug.com > *Subject:* [AFMUG] Elevation question > > > > I have a pretty good GPS receiver. Trimble R8 with a Yuma data > collector. Normally we use it only for lats and longs. > > It is corrected in real time with a cellular data modem and a RTK/VRS > ground station network. > > > > Yesterday we did a shot from a hill that did not exist when shuttle radar > data was taken. It was way off in elevation. > > So we took a shot from our parking lot and compared it with what we think > we know to be the altitude as well as our cell phones and google earth. > > > > Turns out the R8 has an ellipsoid height as well as another height > associated with the northing and easting values. > > The second one seems to be more in line with what I was expecting. > > The local dealer sent me a drawing showing this. (attached) > > > > So now I am super confused. Not sure what number to use when working with > Radio Mobile. Do I add the geoid height to the ellipsoid height? > > > > Was hoping Brian Webster may know or others may know. Googling google > earth elevation talks about different versions of geoid. Not sure if their > elevations are geoid elevations or not. > > > > So, rather than dig into it any more I am taking the lazy approach and > posting the question here. > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
Re: [AFMUG] Elevation question
Thanks. That helps a bunch. And thank your brother too. From: Brian Webster Sent: Wednesday, May 6, 2020 8:35 AM To: 'AnimalFarm Microwave Users Group' Subject: Re: [AFMUG] Elevation question OK here is what I learned from my brother. You want to use the Geoid values, however you also want to make sure you have the Geoid model loaded in to your Trimble R8 GPS. (for those not paying attention that is a survey grade instrument with cm accuracy). The geoid numbers are tied to the map projection you are using and they are also tied to the GPS ground stations you are connected to 9necessary for the cm grade accuracy). The Ellipsoid values assume that the earth is perfectly/mathematically round. Geoid values correct for the fact that it is not perfectly round and the reason why your GPS needs the local Geoid data set loaded before you take readings. You do have the Geoid data for your area loaded don’t you? For radio mobile you will want to use the Geoid height converted to meters. Is there LIDAR data for the area in question? It might be easier just to use a value from that. Might also be nice to convert the LIDAR to a file format for Radio Mobile and use all that data (going to need a lot of disk space though). Thank you, Brian Webster www.wirelessmapping.com From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of ch...@wbmfg.com Sent: Tuesday, May 5, 2020 2:12 PM To: af@af.afmug.com Subject: [AFMUG] Elevation question I have a pretty good GPS receiver. Trimble R8 with a Yuma data collector. Normally we use it only for lats and longs. It is corrected in real time with a cellular data modem and a RTK/VRS ground station network. Yesterday we did a shot from a hill that did not exist when shuttle radar data was taken. It was way off in elevation. So we took a shot from our parking lot and compared it with what we think we know to be the altitude as well as our cell phones and google earth. Turns out the R8 has an ellipsoid height as well as another height associated with the northing and easting values. The second one seems to be more in line with what I was expecting. The local dealer sent me a drawing showing this. (attached) So now I am super confused. Not sure what number to use when working with Radio Mobile. Do I add the geoid height to the ellipsoid height? Was hoping Brian Webster may know or others may know. Googling google earth elevation talks about different versions of geoid. Not sure if their elevations are geoid elevations or not. So, rather than dig into it any more I am taking the lazy approach and posting the question here. -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
Re: [AFMUG] Elevation question
OK here is what I learned from my brother. You want to use the Geoid values, however you also want to make sure you have the Geoid model loaded in to your Trimble R8 GPS. (for those not paying attention that is a survey grade instrument with cm accuracy). The geoid numbers are tied to the map projection you are using and they are also tied to the GPS ground stations you are connected to 9necessary for the cm grade accuracy). The Ellipsoid values assume that the earth is perfectly/mathematically round. Geoid values correct for the fact that it is not perfectly round and the reason why your GPS needs the local Geoid data set loaded before you take readings. You do have the Geoid data for your area loaded don't you? For radio mobile you will want to use the Geoid height converted to meters. Is there LIDAR data for the area in question? It might be easier just to use a value from that. Might also be nice to convert the LIDAR to a file format for Radio Mobile and use all that data (going to need a lot of disk space though). Thank you, Brian Webster www.wirelessmapping.com From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of ch...@wbmfg.com Sent: Tuesday, May 5, 2020 2:12 PM To: af@af.afmug.com Subject: [AFMUG] Elevation question I have a pretty good GPS receiver. Trimble R8 with a Yuma data collector. Normally we use it only for lats and longs. It is corrected in real time with a cellular data modem and a RTK/VRS ground station network. Yesterday we did a shot from a hill that did not exist when shuttle radar data was taken. It was way off in elevation. So we took a shot from our parking lot and compared it with what we think we know to be the altitude as well as our cell phones and google earth. Turns out the R8 has an ellipsoid height as well as another height associated with the northing and easting values. The second one seems to be more in line with what I was expecting. The local dealer sent me a drawing showing this. (attached) So now I am super confused. Not sure what number to use when working with Radio Mobile. Do I add the geoid height to the ellipsoid height? Was hoping Brian Webster may know or others may know. Googling google earth elevation talks about different versions of geoid. Not sure if their elevations are geoid elevations or not. So, rather than dig into it any more I am taking the lazy approach and posting the question here. -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
Re: [AFMUG] Elevation question
I downloaded WiFi Fresnal Zone App to my Moto phone and it has been pretty accurateit uses Google Maps.. They have a pro version as well. On Tue, May 5, 2020, 12:12 PM wrote: > I have a pretty good GPS receiver. Trimble R8 with a Yuma data > collector. Normally we use it only for lats and longs. > It is corrected in real time with a cellular data modem and a RTK/VRS > ground station network. > > Yesterday we did a shot from a hill that did not exist when shuttle radar > data was taken. It was way off in elevation. > So we took a shot from our parking lot and compared it with what we think > we know to be the altitude as well as our cell phones and google earth. > > Turns out the R8 has an ellipsoid height as well as another height > associated with the northing and easting values. > The second one seems to be more in line with what I was expecting. > The local dealer sent me a drawing showing this. (attached) > > So now I am super confused. Not sure what number to use when working with > Radio Mobile. Do I add the geoid height to the ellipsoid height? > > Was hoping Brian Webster may know or others may know. Googling google > earth elevation talks about different versions of geoid. Not sure if their > elevations are geoid elevations or not. > > So, rather than dig into it any more I am taking the lazy approach and > posting the question here. > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
Re: [AFMUG] Elevation question
In the middle of some stuff at the moment, don’t know the answer off the top of my head so let me look it up and consult with my brother than land surveyor. Thank you, Brian Webster www.wirelessmapping.com From: AF [mailto:af-boun...@af.afmug.com] On Behalf Of ch...@wbmfg.com Sent: Tuesday, May 5, 2020 2:20 PM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question I think shuttle data and GE elevations are referenced to a geoid. Not sure if the both use the same geoid. I just want to know which number to use from my machine. Or if I have to do math and use them both to get an elevation that will agree with the shuttle elevations in RM... I agree, Ignorance was bliss... From: Lewis Bergman Sent: Tuesday, May 5, 2020 12:15 PM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question WTF. Ignorance was bliss. Thanls for screwing that up for me Chuck. Now I have to actually think about what to use again. I default back to Google Earth. On Tue, May 5, 2020 at 1:12 PM wrote: I have a pretty good GPS receiver. Trimble R8 with a Yuma data collector. Normally we use it only for lats and longs. It is corrected in real time with a cellular data modem and a RTK/VRS ground station network. Yesterday we did a shot from a hill that did not exist when shuttle radar data was taken. It was way off in elevation. So we took a shot from our parking lot and compared it with what we think we know to be the altitude as well as our cell phones and google earth. Turns out the R8 has an ellipsoid height as well as another height associated with the northing and easting values. The second one seems to be more in line with what I was expecting. The local dealer sent me a drawing showing this. (attached) So now I am super confused. Not sure what number to use when working with Radio Mobile. Do I add the geoid height to the ellipsoid height? Was hoping Brian Webster may know or others may know. Googling google earth elevation talks about different versions of geoid. Not sure if their elevations are geoid elevations or not. So, rather than dig into it any more I am taking the lazy approach and posting the question here. -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- Lewis Bergman 325-439-0533 Cell _ -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
Re: [AFMUG] Elevation question
I think shuttle data and GE elevations are referenced to a geoid. Not sure if the both use the same geoid. I just want to know which number to use from my machine. Or if I have to do math and use them both to get an elevation that will agree with the shuttle elevations in RM... I agree, Ignorance was bliss... From: Lewis Bergman Sent: Tuesday, May 5, 2020 12:15 PM To: AnimalFarm Microwave Users Group Subject: Re: [AFMUG] Elevation question WTF. Ignorance was bliss. Thanls for screwing that up for me Chuck. Now I have to actually think about what to use again. I default back to Google Earth. On Tue, May 5, 2020 at 1:12 PM wrote: I have a pretty good GPS receiver. Trimble R8 with a Yuma data collector. Normally we use it only for lats and longs. It is corrected in real time with a cellular data modem and a RTK/VRS ground station network. Yesterday we did a shot from a hill that did not exist when shuttle radar data was taken. It was way off in elevation. So we took a shot from our parking lot and compared it with what we think we know to be the altitude as well as our cell phones and google earth. Turns out the R8 has an ellipsoid height as well as another height associated with the northing and easting values. The second one seems to be more in line with what I was expecting. The local dealer sent me a drawing showing this. (attached) So now I am super confused. Not sure what number to use when working with Radio Mobile. Do I add the geoid height to the ellipsoid height? Was hoping Brian Webster may know or others may know. Googling google earth elevation talks about different versions of geoid. Not sure if their elevations are geoid elevations or not. So, rather than dig into it any more I am taking the lazy approach and posting the question here. -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- Lewis Bergman 325-439-0533 Cell -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
Re: [AFMUG] Elevation question
WTF. Ignorance was bliss. Thanls for screwing that up for me Chuck. Now I have to actually think about what to use again. I default back to Google Earth. On Tue, May 5, 2020 at 1:12 PM wrote: > I have a pretty good GPS receiver. Trimble R8 with a Yuma data > collector. Normally we use it only for lats and longs. > It is corrected in real time with a cellular data modem and a RTK/VRS > ground station network. > > Yesterday we did a shot from a hill that did not exist when shuttle radar > data was taken. It was way off in elevation. > So we took a shot from our parking lot and compared it with what we think > we know to be the altitude as well as our cell phones and google earth. > > Turns out the R8 has an ellipsoid height as well as another height > associated with the northing and easting values. > The second one seems to be more in line with what I was expecting. > The local dealer sent me a drawing showing this. (attached) > > So now I am super confused. Not sure what number to use when working with > Radio Mobile. Do I add the geoid height to the ellipsoid height? > > Was hoping Brian Webster may know or others may know. Googling google > earth elevation talks about different versions of geoid. Not sure if their > elevations are geoid elevations or not. > > So, rather than dig into it any more I am taking the lazy approach and > posting the question here. > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > -- Lewis Bergman 325-439-0533 Cell -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
[AFMUG] Elevation question
I have a pretty good GPS receiver. Trimble R8 with a Yuma data collector. Normally we use it only for lats and longs. It is corrected in real time with a cellular data modem and a RTK/VRS ground station network. Yesterday we did a shot from a hill that did not exist when shuttle radar data was taken. It was way off in elevation. So we took a shot from our parking lot and compared it with what we think we know to be the altitude as well as our cell phones and google earth. Turns out the R8 has an ellipsoid height as well as another height associated with the northing and easting values. The second one seems to be more in line with what I was expecting. The local dealer sent me a drawing showing this. (attached) So now I am super confused. Not sure what number to use when working with Radio Mobile. Do I add the geoid height to the ellipsoid height? Was hoping Brian Webster may know or others may know. Googling google earth elevation talks about different versions of geoid. Not sure if their elevations are geoid elevations or not. So, rather than dig into it any more I am taking the lazy approach and posting the question here. -- AF mailing list AF@af.afmug.com http://af.afmug.com/mailman/listinfo/af_af.afmug.com
