Re: [time-nuts] GPS position averaging
I compared results from many different timing receiver surveys (VP, UT+,Resolution-T,SMT, Jupiter , that of LH for my T-Bolt, Ublox-6T) with the Google Earth position and with the exception of the Ublox receiver they are all within the bounds of the GE uncertainty which is around 2m from the reports of 2013 I have seen on the web. LH is one of the nearest . The Ublox timing receivers , 6T (2), and navigation 6M,7N and M8N averaged positions (I was letting U-center do the averaging) were not as close even though they are more modern. U-center is showing them 5-7 meters to the north. I have no idea as to why that could be. Le 15 déc. 2014 à 20:18, Mark Sims hol...@hotmail.com a écrit : Take a look at the code in Lady Heather that does a 48 hour precision survey. It calculates a weighted median position of fixes over 1 hour periods then calculates a final position from those medians. The algorithm was developed by having people around the world with Thunderbolts and quality antennas and surveyed antenna positions log data for 48 hours. I processed the data and did some voodoo to come up with the weights, etc that minimized the error in the calculated positions from the surveyed positions. The 48 hour survey interval minimizes the effects of multi-path and satellite orbits, etc. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging
Hi On Dec 15, 2014, at 9:39 PM, Paul tic-...@bodosom.net wrote: On Mon, Dec 15, 2014 at 8:35 PM, Bob Camp kb...@n1k.org wrote: So the question - If they are not going to be equal, which one do you pick? The better one. If the math is sound the presumably the better position results in better time. If there are correlated defects then I suppose the GPS provided solution may be better. None of the various surveys for my primary antenna (which is not optimally located) agree and all are wrong compared to carrier phase solutions. The delta between the various units (Trimble, uBlox and whatever is in the Fury) is greater than the delta between my indoor and outdoor antenna positions in xy. Z not so much. I have seen cases where almost all the error is in Z and the X and Y agree quite well. My *guess* has been that most users don’t fly. The Z error is less of a problem for them. Numbers in the 10’ range are not at all uncommon. That’s enough to potentially add a 10 ns ripple to your data. Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging
olep...@gmail.com said: My question is twofold; 1) is this for some reason a bad idea? And 2) How do I average the numbers? I can not put my finger on it but it feels wrong to average lat, long and height independently. It seems like an interesting idea to me. It would be interesting to run a test: setup a pair of identical GPSDOs running off the same antenna but using different locations and see if you can see any difference in the PPS or 10 MHz output. You can do a filtering pass to dump anything with fewer than 4 satellites. The survey code has a mode where it says bad geometry. I don't know the fine print on how that works. I can get my elevation off a topo map. I'm not sure how to translate that to GPS coordinates. Something like that might be another opportunity for filtering. The refclock part of ntpd filters a batch of samples by discarding outliers. Time is only one dimension, so the recipe is pretty simple: sort, compute the average, discard either the top or bottom, whichever is farther from the average. I'm not sure how to do something similar in 2 or 3 dimensions. It might be interesting to make histograms of HDOP and friends. (before and after any filtering you can come up with?) That may cover the bad-geometry case. -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging
I am new to this list and to this topic, but it seems to me that if one wants to come up with an average of a set of spatial measurements, one would use distance as the parameter to be averaged. The distance would presumably be that from a fixed spatial reference point (0,0,0). One would then take the square root of the sum of the squares of latitude, longitude and height. My problem with this is that I can't see what one would use for the reference point, but maybe that is not important (or maybe it is!). DaveD On 12/15/2014 2:48 AM, Hal Murray wrote: olep...@gmail.com said: My question is twofold; 1) is this for some reason a bad idea? And 2) How do I average the numbers? I can not put my finger on it but it feels wrong to average lat, long and height independently. It seems like an interesting idea to me. It would be interesting to run a test: setup a pair of identical GPSDOs running off the same antenna but using different locations and see if you can see any difference in the PPS or 10 MHz output. You can do a filtering pass to dump anything with fewer than 4 satellites. The survey code has a mode where it says bad geometry. I don't know the fine print on how that works. I can get my elevation off a topo map. I'm not sure how to translate that to GPS coordinates. Something like that might be another opportunity for filtering. The refclock part of ntpd filters a batch of samples by discarding outliers. Time is only one dimension, so the recipe is pretty simple: sort, compute the average, discard either the top or bottom, whichever is farther from the average. I'm not sure how to do something similar in 2 or 3 dimensions. It might be interesting to make histograms of HDOP and friends. (before and after any filtering you can come up with?) That may cover the bad-geometry case. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging
I would recommend determining your terrain's elevation using a topo map and estimating or measuring antennas height above ground. And then excluding survey results with wacko altitudes before averaging. While we often set the elevation angle mask high for timing purposes, for survey purposes especially altitude it will likely be best to do survey with no or very low (10 degree default?) elevation mask. The Z3801A manual tells how to set elevation mask for at least some of your units. Tim N3QE On Mon, Dec 15, 2014 at 4:03 AM, Ole Petter Ronningen olep...@gmail.com wrote: Hello, all I have a couple of GPSDOs (KS, z3805a) hooked up to a fixed outdoor antenna through an HP 58516 splitter. I notice that when I powercycle the GPSDOs (which I generally try to avoid), the position they come up with differs from time to time in at least the last three digits (and height in particular varies with up to 30m). I would like to get a better idea of what my actualt antenna location is, so that I can manually set the position in the GPSDOs. For that purpose I set up a Ublox M8N with logging in U-center, and I've collected about 250K readings over several days. For each reading I also log number of SV's used, as well as HDOP, VDOP. PDOP, thinking I would filter the list and end up with a subset of really good fixes.The idea is then to average the best readings and use that as my position. My question is twofold; 1) is this for some reason a bad idea? And 2) How do I average the numbers? I can not put my finger on it but it feels wrong to average lat, long and height independently. Any hints are greatly appreciated. Thank you! Ole P ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging
The Ublox M8N can send out raw measurements with messages TRK-MEAS and TRK-SFRBX for observation and navigation data: you can postprocess them to improve the accuracy. http://www.rtklib.com/rtklib_support.htm On Mon, Dec 15, 2014 at 12:43 PM, Tim Shoppa tsho...@gmail.com wrote: I would recommend determining your terrain's elevation using a topo map and estimating or measuring antennas height above ground. And then excluding survey results with wacko altitudes before averaging. While we often set the elevation angle mask high for timing purposes, for survey purposes especially altitude it will likely be best to do survey with no or very low (10 degree default?) elevation mask. The Z3801A manual tells how to set elevation mask for at least some of your units. Tim N3QE On Mon, Dec 15, 2014 at 4:03 AM, Ole Petter Ronningen olep...@gmail.com wrote: Hello, all I have a couple of GPSDOs (KS, z3805a) hooked up to a fixed outdoor antenna through an HP 58516 splitter. I notice that when I powercycle the GPSDOs (which I generally try to avoid), the position they come up with differs from time to time in at least the last three digits (and height in particular varies with up to 30m). I would like to get a better idea of what my actualt antenna location is, so that I can manually set the position in the GPSDOs. For that purpose I set up a Ublox M8N with logging in U-center, and I've collected about 250K readings over several days. For each reading I also log number of SV's used, as well as HDOP, VDOP. PDOP, thinking I would filter the list and end up with a subset of really good fixes.The idea is then to average the best readings and use that as my position. My question is twofold; 1) is this for some reason a bad idea? And 2) How do I average the numbers? I can not put my finger on it but it feels wrong to average lat, long and height independently. Any hints are greatly appreciated. Thank you! Ole P ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging
On Mon, Dec 15, 2014 at 10:52 AM, Azelio Boriani azelio.bori...@gmail.com wrote: The Ublox M8N can send out raw measurements with messages TRK-MEAS and TRK-SFRBX for observation and navigation data: you can postprocess them to improve the accuracy. And searching the archives for rtklib should find some relevant posts with pointers to post-processing. Naturally the output of rtklib doesn't quite agree with the Canadian (CSRS-PPP) results although that could just be operator error. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging
Hi Simple answer - there is no simple answer. You will get significantly better results by intelligently processing the data than by a giant “average everything in sight” approach. Also consider that various GPS modules seem to have offsets in their nav solution. The NIST papers on various GPSDO’s show this pretty clearly. Simply having a “correct” solution may not help as much as you might think. Of course if you want a truly correct solution, your local surveyor is indeed your best friend. He probably has a GPS gizmo that with about a half hour or sitting there, tell you where you are to under an inch. Who knows how much that will cost. It probably depends on how interested you can get him in coming over and looking at your toys. Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging
On Mon, 15 Dec 2014 17:55:20 -0500, you wrote: Hi Simple answer - there is no simple answer. You will get significantly better results by intelligently processing the data than by a giant average everything in sight approach. Also consider that various GPS modules seem to have offsets in their nav solution. The NIST papers on various GPSDOs show this pretty clearly. Simply having a correct solution may not help as much as you might think. Of course if you want a truly correct solution, your local surveyor is indeed your best friend. He probably has a GPS gizmo that with about a half hour or sitting there, tell you where you are to under an inch. Who knows how much that will cost. It probably depends on how interested you can get him in coming over and looking at your toys. But is it the closest to the 'true' position that you really want, or the best estimate of where the particular GPS you are testing thinks it is? Angus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging
Hi On Dec 15, 2014, at 6:39 PM, Angus not.ag...@btinternet.com wrote: On Mon, 15 Dec 2014 17:55:20 -0500, you wrote: Hi Simple answer - there is no simple answer. You will get significantly better results by intelligently processing the data than by a giant average everything in sight approach. Also consider that various GPS modules seem to have offsets in their nav solution. The NIST papers on various GPSDOs show this pretty clearly. Simply having a correct solution may not help as much as you might think. Of course if you want a truly correct solution, your local surveyor is indeed your best friend. He probably has a GPS gizmo that with about a half hour or sitting there, tell you where you are to under an inch. Who knows how much that will cost. It probably depends on how interested you can get him in coming over and looking at your toys. But is it the closest to the 'true' position that you really want, or the best estimate of where the particular GPS you are testing thinks it is? I would *guess* that the position reported by the GPS would be the better alternative. The distances (errors) involved are often fairly small. Proving which one is correct may not be easy. Obviously, the ideal case is the one where there is no error. If the error exists it says that the firmware has some sort of bug. Of course *my* code never ever has bugs … :) Bob Angus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging
This may be one of those cases where the human brain's ability to see patterns would help to see the distribution and eliminate outliers. Plot a manageable set of X and Y points, and another set of X and Z points. To make the three dimensions plot as one in a statistical distribution (bell) curve, use the magnitude of the vector. What do the surveyors instruments do that can get them down to a few centimeters in half an hour? You might also want to study what's been said about the causes of variance. The atmosphere is not uniform. Consider the relative effect of position on time, where one foot or 30 cm is equivalent to 10E-9 second. Also consider the 'averaging' period of the PLL filter in the disciplined oscillator. I'm no expert, especially not in math. These hints are thoughts that come to mind. Bill Hawkins -Original Message- From: Ole Petter Ronningen Sent: Monday, December 15, 2014 3:04 AM I would like to get a better idea of what my actualt antenna location is, so that I can manually set the position in the GPSDOs. For that purpose I set up a Ublox M8N with logging in U-center, and I've collected about 250K readings over several days. For each reading I also log number of SV's used, as well as HDOP, VDOP. PDOP, thinking I would filter the list and end up with a subset of really good fixes.The idea is then to average the best readings and use that as my position. My question is twofold; 1) is this for some reason a bad idea? And 2) How do I average the numbers? I can not put my finger on it but it feels wrong to average lat, long and height independently. Any hints are greatly appreciated. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging
Hi On Dec 15, 2014, at 7:19 PM, Bill Hawkins b...@iaxs.net wrote: This may be one of those cases where the human brain's ability to see patterns would help to see the distribution and eliminate outliers. Plot a manageable set of X and Y points, and another set of X and Z points. yup To make the three dimensions plot as one in a statistical distribution (bell) curve, use the magnitude of the vector. What do the surveyors instruments do that can get them down to a few centimeters in half an hour? The ones around here use a survey grade GPS and log the data to a file. They do a bunch of post processing to get the solution to a desired level of accuracy. Last time I had it done, they had more fun looking at the GPSDO’s than running their fancy GPS. You might also want to study what's been said about the causes of variance. The atmosphere is not uniform. Ionospheric issues are one of the things that gets corrected for to make a more accurate result. Consider the relative effect of position on time, where one foot or 30 cm is equivalent to 10E-9 second. …. and some of the errors between solutions are 10 feet. Also consider the 'averaging' period of the PLL filter in the disciplined oscillator. The problem shows up when the GPS constellation is in a configuration that accentuates the error. That’s often a 12 / 24 / 48 hour sort of thing. Bob I'm no expert, especially not in math. These hints are thoughts that come to mind. Bill Hawkins -Original Message- From: Ole Petter Ronningen Sent: Monday, December 15, 2014 3:04 AM I would like to get a better idea of what my actualt antenna location is, so that I can manually set the position in the GPSDOs. For that purpose I set up a Ublox M8N with logging in U-center, and I've collected about 250K readings over several days. For each reading I also log number of SV's used, as well as HDOP, VDOP. PDOP, thinking I would filter the list and end up with a subset of really good fixes.The idea is then to average the best readings and use that as my position. My question is twofold; 1) is this for some reason a bad idea? And 2) How do I average the numbers? I can not put my finger on it but it feels wrong to average lat, long and height independently. Any hints are greatly appreciated. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging
Hi Actually there may be a Time Nuts relevant reason for wanting to know the true / correct / survey location. If your desire is to know UTC to ns or something like that, an indicated position error *probably* relates directly to a time error. Being able to correct the position error may allow you to better estimate the UTC time error. Bob On Dec 15, 2014, at 6:39 PM, Angus not.ag...@btinternet.com wrote: On Mon, 15 Dec 2014 17:55:20 -0500, you wrote: Hi Simple answer - there is no simple answer. You will get significantly better results by intelligently processing the data than by a giant average everything in sight approach. Also consider that various GPS modules seem to have offsets in their nav solution. The NIST papers on various GPSDOs show this pretty clearly. Simply having a correct solution may not help as much as you might think. Of course if you want a truly correct solution, your local surveyor is indeed your best friend. He probably has a GPS gizmo that with about a half hour or sitting there, tell you where you are to under an inch. Who knows how much that will cost. It probably depends on how interested you can get him in coming over and looking at your toys. But is it the closest to the 'true' position that you really want, or the best estimate of where the particular GPS you are testing thinks it is? Angus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging
kb...@n1k.org said: The problem shows up when the GPS constellation is in a configuration that accentuates the error. Thatâs often a 12 / 24 / 48 hour sort of thing. It would be interesting to compare the results from daytime vs nighttime, or today vs yesterday. -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging
Hi On Dec 15, 2014, at 8:07 PM, Hal Murray hmur...@megapathdsl.net wrote: kb...@n1k.org said: The problem shows up when the GPS constellation is in a configuration that accentuates the error. That’s often a 12 / 24 / 48 hour sort of thing. It would be interesting to compare the results from daytime vs nighttime, or today vs yesterday. There can be seasonal issues (trees sprout leaves …) as well. Bob -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging
On Mon, Dec 15, 2014 at 6:39 PM, Angus not.ag...@btinternet.com wrote: But is it the closest to the 'true' position that you really want, or the best estimate of where the particular GPS you are testing thinks it is? I don't understand what you're saying here. Can you phrase it differently? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging
Hi On Dec 15, 2014, at 8:29 PM, Paul tic-...@bodosom.net wrote: On Mon, Dec 15, 2014 at 6:39 PM, Angus not.ag...@btinternet.com wrote: But is it the closest to the 'true' position that you really want, or the best estimate of where the particular GPS you are testing thinks it is? I don't understand what you're saying here. Can you phrase it differently? I proposed two possible solutions to the problem: 1) Do the long term average with your specific GPS gizmo. 2) Get a survey grade GPS in and determine the “real” location. The NIST papers do indicate that #1 does not equal #2 for the gear they tested. So the question - If they are not going to be equal, which one do you pick? Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging
On 12/15/14, 5:35 PM, Bob Camp wrote: Hi On Dec 15, 2014, at 8:29 PM, Paul tic-...@bodosom.net wrote: On Mon, Dec 15, 2014 at 6:39 PM, Angus not.ag...@btinternet.com wrote: But is it the closest to the 'true' position that you really want, or the best estimate of where the particular GPS you are testing thinks it is? I don't understand what you're saying here. Can you phrase it differently? I proposed two possible solutions to the problem: 1) Do the long term average with your specific GPS gizmo. 2) Get a survey grade GPS in and determine the “real” location. The NIST papers do indicate that #1 does not equal #2 for the gear they tested. So the question - If they are not going to be equal, which one do you pick? if you've got observables and they're in RINEX format, you can do offline processing through JPL's GIPSY thing.. If you're looking at data that's a week old, they've had plenty of time to process all the observed satellite behavior, calculate ionospheric corrections, changes in earth's rotation due to earthquakes and tsunamis, and all that sort of stuff. http://apps.gdgps.net/ Oddly, the picture of the guy on the cellphone in the left side of the banner looks like Yoaz Bar-Sever, who runs the gdgps stuff. Why he's on a phone, I'm not sure.. apps is more of a file/web sort of thing. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging
On Mon, Dec 15, 2014 at 8:35 PM, Bob Camp kb...@n1k.org wrote: So the question - If they are not going to be equal, which one do you pick? The better one. If the math is sound the presumably the better position results in better time. If there are correlated defects then I suppose the GPS provided solution may be better. None of the various surveys for my primary antenna (which is not optimally located) agree and all are wrong compared to carrier phase solutions. The delta between the various units (Trimble, uBlox and whatever is in the Fury) is greater than the delta between my indoor and outdoor antenna positions in xy. Z not so much. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging
On Mon, Dec 15, 2014 at 9:01 PM, Jim Lux jim...@earthlink.net wrote: if you've got observables and they're in RINEX format, you can do offline processing through JPL's GIPSY thing.. According to the upload form APPS still requires dual frequency. The underlying Gipsy system may not have that constraint but I opted used CSRS-PPP to check the RTKLIB output rather than worry about it. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging
On 12/15/14, 6:46 PM, Paul wrote: On Mon, Dec 15, 2014 at 9:01 PM, Jim Lux jim...@earthlink.net wrote: if you've got observables and they're in RINEX format, you can do offline processing through JPL's GIPSY thing.. According to the upload form APPS still requires dual frequency. The underlying Gipsy system may not have that constraint but I opted used CSRS-PPP to check the RTKLIB output rather than worry about it. ___ Interesting.. I'll ask them later this week when I'm back on lab. I was under the impression that they can do single frequency GIPSY processing. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging software?
Thanks, all, for the suggestions. I'm playing with WinOncore12 at the moment -- for some reason I'm not able to get the M12+ receiver into NMEA mode so VisualGPS isn't usable. I'll fuss more with NMEA mode this weekend, but is there any magic for the ioformat switch? I've used the command from both Tac32 and WinOncore but the receiver stays stuck in binary mode. John On 4/13/2011 3:05 AM, David J Taylor wrote: John, Visual GPS (http://visualgps.net/) will do this for you. [] -Kevin Seconded. It works with Garmin GPS 12 XL and GPS 60 CSx, and likely many others. Very nice position performance plot with both mean and least squares averages. I've just tried the u-Blox Control Center which Achim mentioned, and that looks like a useful test toll as well. David ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging software?
Hello John, If your M12+ is a Timing model, then there is no NMEA mode... HTH, Regards, Jean-Louis - Original Message - From: John Ackermann N8UR j...@febo.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, April 14, 2011 3:35 PM Subject: Re: [time-nuts] GPS position averaging software? Thanks, all, for the suggestions. I'm playing with WinOncore12 at the moment -- for some reason I'm not able to get the M12+ receiver into NMEA mode so VisualGPS isn't usable. I'll fuss more with NMEA mode this weekend, but is there any magic for the ioformat switch? I've used the command from both Tac32 and WinOncore but the receiver stays stuck in binary mode. John On 4/13/2011 3:05 AM, David J Taylor wrote: John, Visual GPS (http://visualgps.net/) will do this for you. [] -Kevin Seconded. It works with Garmin GPS 12 XL and GPS 60 CSx, and likely many others. Very nice position performance plot with both mean and least squares averages. I've just tried the u-Blox Control Center which Achim mentioned, and that looks like a useful test toll as well. David ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging software?
It is a timing model, and I wondered about that, but thought it was only one of the old GT/UT models that was binary only. Thanks! It means I may not be going crazy, after all... John On 4/14/2011 12:16 PM, Jean-Louis Oneto wrote: Hello John, If your M12+ is a Timing model, then there is no NMEA mode... HTH, Regards, Jean-Louis - Original Message - From: John Ackermann N8UR j...@febo.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, April 14, 2011 3:35 PM Subject: Re: [time-nuts] GPS position averaging software? Thanks, all, for the suggestions. I'm playing with WinOncore12 at the moment -- for some reason I'm not able to get the M12+ receiver into NMEA mode so VisualGPS isn't usable. I'll fuss more with NMEA mode this weekend, but is there any magic for the ioformat switch? I've used the command from both Tac32 and WinOncore but the receiver stays stuck in binary mode. John On 4/13/2011 3:05 AM, David J Taylor wrote: John, Visual GPS (http://visualgps.net/) will do this for you. [] -Kevin Seconded. It works with Garmin GPS 12 XL and GPS 60 CSx, and likely many others. Very nice position performance plot with both mean and least squares averages. I've just tried the u-Blox Control Center which Achim mentioned, and that looks like a useful test toll as well. David ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging software?
I did this with our newly installed Thunderbolt. When I plugged the coordinates into Google Earth, the center of the image was dead on with the skylight where the antenna is. Not just pointing at the skylight, but the correct part of the skylight. Could be coincidence, but I'd say the error was 1'. I don't have any convenient surveyed points available to check with. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging software?
Google earth isn't very accurate, so I would chalk this up to coincidence. There is a USGS website with accurate waypoints, some of which are visible via satellite. (Literally X marks the spot. They can be seen on google earth.) I don't recall the URL at the moment, but I'm sure somebody on the list has it. I've used this to test GPSs in the past. I've found my Garmin gps60csx locks in to 4ft, pretty much the resolution. The vast majority of these reference marks are in the middle of the road. It takes a bit of work to find one that you can visit (public land) and linger on scene to do averaging. It is the USGS NAIS database IIRC. --Original Message-- From: David VanHorn Sender: time-nuts-boun...@febo.com To: Discussion of precise time and frequency measurement ReplyTo: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] GPS position averaging software? Sent: Apr 13, 2011 7:44 AM I did this with our newly installed Thunderbolt. When I plugged the coordinates into Google Earth, the center of the image was dead on with the skylight where the antenna is. Not just pointing at the skylight, but the correct part of the skylight. Could be coincidence, but I'd say the error was 1'. I don't have any convenient surveyed points available to check with. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging software?
True, but my setup isn't very portable. I'm happy, I'm getting my 10.00 MHz output and it's WAY more accurate than I need. The rest is delicious bacon gravy! ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging software?
The Motorola software (Winoncore, Google will find it at www.synergy-gps.com) has a feature that plots position average, actually two averages it give s a running mean and a running least squares and plots both on Lat Long. My Oncore GPS is connected to a LInux based server but I run the Win XP software in VMware. There is also tac32 but it seem to be slightly less sophisticated than the free software Motorola supplied with the GPS units. On Tue, Apr 12, 2011 at 7:28 PM, Mark Sims hol...@hotmail.com wrote: Why Lady Heather, of course! Requires a Thunderbolt. Use the S)urvey P)recision command. You can specify the number of hours to run for (default is 48). During the survey all the fixes are written to the file LLA.LLA and plotted on the screen (each hour in a different color). It does some pseudo sophisto statisto mumbo jumbo on the fixes and comes up with a pretty good guess where you are and saves that as your location. You can also read in a .LLA file and it will plot the fixes, or you can process them with your own software. You can stop a survey early if you want (I don't rememeber if it saves the position if you do that) I have tested lots of different antennas and the differences can be rather significant. My best survey grade choke ring comes in within less than a foot. Crappy patch antennas can be off over 10 feet. If you just have to use the M12 receiver, you could format the fixes into a .LLA file and then read it with Lady Heather. You can start the program with the /0 option to disable its attempt to use a serial port to talk to a thunderbolt. Also note that the program does not buffer the fixes... if you redraw the screen, etc, the plot goes away. And you can't zoom the LLA plot to full screen. - Just got a pair of GPS antennas on the roof and I'm interested in both getting as accurate a position survey as I can, and in comparing the performance of the two antennas -- one is a choke ring, the other a Motorola Timing2000. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- = Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging software?
John, I use WinOncore12, it's written by motorola, but no longer supported by them. You can get the install file from here http://www.jackson-labs.com/support.html On 2011-04-13 11:44, John Ackermann N8UR wrote: Just got a pair of GPS antennas on the roof and I'm interested in both getting as accurate a position survey as I can, and in comparing the performance of the two antennas -- one is a choke ring, the other a Motorola Timing2000. I'm using an M12+ receiver. I have TAC32 but am interested in other software that may have more focus on positioning, e.g. showing a plot of the wander and providing statistics about the averaging. Any suggestions? John -- Cheers, Ken vk7...@users.tasmanet.com.au www.vk7krj.com 'It seems hard to sneak a look at God's cards. But that He plays dice and uses telepathic methods is something that I cannot believe for a single moment.' (Einstein's famous quote on Quantum theory) No virus found in this outgoing message. Checked by AVG - www.avg.com Version: 9.0.894 / Virus Database: 271.1.1/3569 - Release Date: 04/13/11 04:35:00 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging software?
John, Visual GPS (http://visualgps.net/) will do this for you. RTKLIB may also be of interest (http://gpspp.sakura.ne.jp/rtklib/). -Kevin - Original Message - From: John Ackermann N8UR j...@febo.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Tuesday, April 12, 2011 6:44 PM Subject: [time-nuts] GPS position averaging software? Just got a pair of GPS antennas on the roof and I'm interested in both getting as accurate a position survey as I can, and in comparing the performance of the two antennas -- one is a choke ring, the other a Motorola Timing2000. I'm using an M12+ receiver. I have TAC32 but am interested in other software that may have more focus on positioning, e.g. showing a plot of the wander and providing statistics about the averaging. Any suggestions? John ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] GPS position averaging software?
John, try out the u-Blox Control Center at www.ublox.com. Primarily writte for their suite of GPS units, but works just fine with any NMEA enabled receiver. 73s Achim, DH2VA ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
