Re: GPS -- AGPS
On Sunday 08 June 2008 18:07, [EMAIL PROTECTED] wrote: On Sunday 08 June 2008 10:41:37 Brad Midgley wrote: Tim gpsd has a mode where it listens to both the gps and an online dgps source and produces corrected output. See the manpage for gpsd. I think you have to have the unit online continuously. Does gpsd have control over the various satelite signals? I thought D-GPS only works before position calculation. If gpsd only gets the composed position, then it's not possible to do D-GPS. I'm not an expert here, but maybe correction does require more raw data. It might depend on what the protocol is between gpsd and the gps. The gpsd docs don't shed any more light on it. It would be a good question for the gpsd mailing lists. The problem here is not with gpsd but rather that we might not be able to get the required raw satellite measurements out of the Antaris chip due to some licence restriction :( Not having a Freerunner at hand, I wrote a crude test program for accessing the required rxm-raw message of the GPS chip and sent it to Andy Green. The results were not encouraging - although I'd love to hear some official statement about the license status for the GPS chip before jumping to premature conclusions but currently it seems that DGPS will not be possible with the Freerunner. It indeed looks like that, which is a pity, because this could have been a feature really setting the Freerunner apart from other devices. AVee -- You are only young once, but you can stay immature indefinitely. ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: GPS -- AGPS
Hallo Brad, * Brad Midgley [EMAIL PROTECTED] [06-06-08 07:14]: Joseph That's what I, as an archaeologist, want D-GPS for :) gpsd has a mode where it listens to both the gps and an online dgps source and produces corrected output. See the manpage for gpsd. I think you have to have the unit online continuously. Does gpsd have control over the various satelite signals? I thought D-GPS only works before position calculation. If gpsd only gets the composed position, then it's not possible to do D-GPS. Tim Niemeyer signature.asc Description: Digital signature ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: GPS -- AGPS
On Sunday 08 June 2008 10:41:37 Brad Midgley wrote: Tim gpsd has a mode where it listens to both the gps and an online dgps source and produces corrected output. See the manpage for gpsd. I think you have to have the unit online continuously. Does gpsd have control over the various satelite signals? I thought D-GPS only works before position calculation. If gpsd only gets the composed position, then it's not possible to do D-GPS. I'm not an expert here, but maybe correction does require more raw data. It might depend on what the protocol is between gpsd and the gps. The gpsd docs don't shed any more light on it. It would be a good question for the gpsd mailing lists. The problem here is not with gpsd but rather that we might not be able to get the required raw satellite measurements out of the Antaris chip due to some licence restriction :( Not having a Freerunner at hand, I wrote a crude test program for accessing the required rxm-raw message of the GPS chip and sent it to Andy Green. The results were not encouraging - although I'd love to hear some official statement about the license status for the GPS chip before jumping to premature conclusions but currently it seems that DGPS will not be possible with the Freerunner. --beren ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: GPS -- AGPS
Aaaaha, I seen it being used for all sorts of archeology and buildings construction purposes. That's what I, as an archaeologist, want D-GPS for :) With AGPS for quicker acquisition time (I'm thinking this will be particularly useful when your phone's in your pocket in suspend mode - turn it on and it starts working quicker). Marcus Bauer had previously sent me this link: http://www.u-blox.com/customersupport/docs/GPS_Compendium(GPS-X-02007).pdf Chapter 6 deals nicely with improving GPS performance. Joseph On 06/06/2008, Joerg Reisenweber [EMAIL PROTECTED] wrote: Am Fr 6. Juni 2008 schrieb Flyin_bbb8: just wanted to add, Differential GPS is mainly for aircraft GPS systems to get better guidance on the ILS (Instrument Landing System). Aaaaha, I seen it being used for all sorts of archeology and buildings construction purposes. And from the info in the uBlox-paper, regarding the protocol options it doesn't seem to me like there is much chance for better precision by the way they do A-GPS. Better precision would mean info on meteorological interference (like exact amount clouds on the way to sat) at the very location of the receiver. To get this, you need... a reference receiver, so we are at D-GPS again. /j ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: GPS -- AGPS
Joseph That's what I, as an archaeologist, want D-GPS for :) gpsd has a mode where it listens to both the gps and an online dgps source and produces corrected output. See the manpage for gpsd. I think you have to have the unit online continuously. -- Brad ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: GPS -- AGPS
Brad Midgley wrote: Yorick Maybe I missed somehting, but to my knowlegde the AGPS is not yet working on the Freerunner. Is there any work being done to get AGPS working? Does anybody have an idea if it will ever be implemented or not? And if it will be implemented, when will it be ready? Len Chen sent a pdf to the list last month with gps comparisons. The last paragraph of his writeup seems to suggest that freerunner's implementation of the gps module lacks the ability to do agps. Hi all, Here is the reference about AGPS implementation. http://people.openmoko.org/matt_hsu/ImplementationAssistNowServerAndClient(GPS.G4-SW-05017-C).pdf Cheers, Matt ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
GPS -- AGPS
** Matt said: http://people.openmoko.org/matt_hsu/ImplementationAssistNowServerAndClient(GPS.G4-SW-05017-C).pdf Cheers, Matt *** I get the impression there is only informtion to have AGPS working with an internet connection. I was under the impression that AGPS would be possible over the GSM-network. Will this be implemented or is it impossible? y _ De mooiste afbeeldingen van Angelina Jolie vind je met Live Search http://search.live.com/images/results.aspx?q=angelina%20jolieFORM=MIINTM___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
GPS -- AGPS
** Matt said: http://people.openmoko.org/matt_hsu/ImplementationAssistNowServerAndClient(GPS.G4-SW-05017-C).pdf Cheers, Matt *** Scratch my previous question, I realise now that it was a stupid one :) _ Probeer Live Search: de zoekmachine van de makers van MSN! http://www.live.com/?searchOnly=true___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: GPS -- AGPS
I'm sorry if this question is completely ignorant, but I am always seeking understanding, and my previous understanding is inconsistant with the discussion here. I had originally believed 2 things. First, that AGPS was required by law in all US cell phones (Possibly elsewhere). And second, I had believed that AGPS was simply GPS with assistence from triangulating off of the GSM towers as well. Meaning, I thought AGPS was a combination of satallite GPS and the sort of triangulation Google Maps does in the iPhone. Further, I thought I read a comment somewhere, maybe a year ago, maybe more, (And I can't find the reference now) to the effect of because the neo is required to have an AGPS chip, we will be giving the user access. And so I guess my question is, is it legal to operate the Neo without AGPS? And is there more (Or less) functionality coming from the assist portion of the AGPS? In all fairness, I have been confused before, and I will be confused again. I hope my ignorance hasn't opened up a larger can of worms... Thank you in advance for your response. ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: GPS -- AGPS
A quick look on google says that GPS is required for all cell phones (well, E911 requires that 911 calls from cell phones also get the coordinates, and operators didn't want to change all their towers, so they started requiring their phones to have GPS). Sadly, most phones don't allow application access to that data, perhaps due to some cost-saving measures (like stripping down the correlator, etc). AFAIK, the AGPS allows you to upload additional information into the onboard correlator (the CPU that does the actual location calculations for GPS) to enhance the accuracy over what you get with simple satellite triangulation. On Thu, Jun 5, 2008 at 12:36 PM, Tyrell Berry [EMAIL PROTECTED] wrote: I'm sorry if this question is completely ignorant, but I am always seeking understanding, and my previous understanding is inconsistant with the discussion here. I had originally believed 2 things. First, that AGPS was required by law in all US cell phones (Possibly elsewhere). And second, I had believed that AGPS was simply GPS with assistence from triangulating off of the GSM towers as well. Meaning, I thought AGPS was a combination of satallite GPS and the sort of triangulation Google Maps does in the iPhone. Further, I thought I read a comment somewhere, maybe a year ago, maybe more, (And I can't find the reference now) to the effect of because the neo is required to have an AGPS chip, we will be giving the user access. And so I guess my question is, is it legal to operate the Neo without AGPS? And is there more (Or less) functionality coming from the assist portion of the AGPS? In all fairness, I have been confused before, and I will be confused again. I hope my ignorance hasn't opened up a larger can of worms... Thank you in advance for your response. ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community -- H. Lally Singh Ph.D. Candidate, Computer Science Virginia Tech ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: GPS -- AGPS
Am Do 5. Juni 2008 schrieb Lally Singh: AFAIK, the AGPS allows you to upload additional information into the onboard correlator (the CPU that does the actual location calculations for GPS) to enhance the accuracy over what you get with simple satellite triangulation. It's about reducing TTFF, not increasing accuracy [1]. Basically you tell the receiver which sats it should expect, so it doesn't have to check all possible channels and download the data from sat (AFAIK). See ephem and alm in uBlox paper. [1] Increasing accuracy is differential-GPS, where you have a reference receiver at known position, so you can tell pos of 2nd relative to ref in sub-meter accuracy. Also see: http://wiki.openmoko.org/wiki/Hardware:AGPS which I found just after typing the above. /j signature.asc Description: This is a digitally signed message part. ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: GPS -- AGPS
On Thu, Jun 5, 2008 at 7:25 PM, Joerg Reisenweber [EMAIL PROTECTED] wrote: Am Do 5. Juni 2008 schrieb Lally Singh: AFAIK, the AGPS allows you to upload additional information into the onboard correlator (the CPU that does the actual location calculations for GPS) to enhance the accuracy over what you get with simple satellite triangulation. It's about reducing TTFF, not increasing accuracy [1]. Basically you tell the receiver which sats it should expect, so it doesn't have to check all possible channels and download the data from sat (AFAIK). See ephem and alm in uBlox paper. [1] Increasing accuracy is differential-GPS, where you have a reference receiver at known position, so you can tell pos of 2nd relative to ref in sub-meter accuracy. Also see: http://wiki.openmoko.org/wiki/Hardware:AGPS which I found just after typing the above. Ah, my mistake. I was hoping for more than just an almanac/ephem upload. I'm a lot less excited now. -- H. Lally Singh Ph.D. Candidate, Computer Science Virginia Tech ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: GPS -- AGPS
actually i believe it does help in much better accuracy (unless if you're indoors) On Fri, Jun 6, 2008 at 3:11 AM, Lally Singh [EMAIL PROTECTED] wrote: On Thu, Jun 5, 2008 at 7:25 PM, Joerg Reisenweber [EMAIL PROTECTED] wrote: Am Do 5. Juni 2008 schrieb Lally Singh: AFAIK, the AGPS allows you to upload additional information into the onboard correlator (the CPU that does the actual location calculations for GPS) to enhance the accuracy over what you get with simple satellite triangulation. It's about reducing TTFF, not increasing accuracy [1]. Basically you tell the receiver which sats it should expect, so it doesn't have to check all possible channels and download the data from sat (AFAIK). See ephem and alm in uBlox paper. [1] Increasing accuracy is differential-GPS, where you have a reference receiver at known position, so you can tell pos of 2nd relative to ref in sub-meter accuracy. Also see: http://wiki.openmoko.org/wiki/Hardware:AGPS which I found just after typing the above. Ah, my mistake. I was hoping for more than just an almanac/ephem upload. I'm a lot less excited now. -- H. Lally Singh Ph.D. Candidate, Computer Science Virginia Tech ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: GPS -- AGPS
Am Fr 6. Juni 2008 schrieb Flyin_bbb8: just wanted to add, Differential GPS is mainly for aircraft GPS systems to get better guidance on the ILS (Instrument Landing System). Aaaaha, I seen it being used for all sorts of archeology and buildings construction purposes. And from the info in the uBlox-paper, regarding the protocol options it doesn't seem to me like there is much chance for better precision by the way they do A-GPS. Better precision would mean info on meteorological interference (like exact amount clouds on the way to sat) at the very location of the receiver. To get this, you need... a reference receiver, so we are at D-GPS again. /j signature.asc Description: This is a digitally signed message part. ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: GPS -- AGPS
An *A-GPS* receiver can address these problems in several ways, using an *Assistance Server*: - The Assistance Server can locate the phone roughly by what cell sitehttp://en.wikipedia.org/wiki/Cell_siteit is connected to on the cellular network http://en.wikipedia.org/wiki/Cellular_network. - The Assistance Server has a good satellite signal, and lots of computation power, so it can compare fragmentary signals relayed to it by cell phones, with the satellite signal it receives directly, and then inform the cell phone or emergency services of the cell phone's position. - It can supply orbital data http://en.wikipedia.org/wiki/Ephemeris for the GPS satellites to the cell phone, enabling the cell phone to lock to the satellites when it otherwise could not, and autonomously calculate its position. - It can have better knowledge of ionospherichttp://en.wikipedia.org/wiki/Ionosphericconditions and other errors affecting the GPS signal than the cell phone alone, enabling more precise calculation of position. (See also Wide Area Augmentation Systemhttp://en.wikipedia.org/wiki/Wide_Area_Augmentation_System) Info from http://en.wikipedia.org/wiki/AGPS ,(I'm not 100% sure about the precision but at least that's what alot of people have told me, and so does other websites ), have you run any tests yet Joerg? I know they do use D-GPS in other industries other than aviation that's exactly why i said mainly and not only, go ahead and tell me why they made D-GPS in the first place, and then added the small error in it by the department of defense of the US :) On Fri, Jun 6, 2008 at 7:46 AM, Joerg Reisenweber [EMAIL PROTECTED] wrote: Am Fr 6. Juni 2008 schrieb Flyin_bbb8: just wanted to add, Differential GPS is mainly for aircraft GPS systems to get better guidance on the ILS (Instrument Landing System). Aaaaha, I seen it being used for all sorts of archeology and buildings construction purposes. And from the info in the uBlox-paper, regarding the protocol options it doesn't seem to me like there is much chance for better precision by the way they do A-GPS. Better precision would mean info on meteorological interference (like exact amount clouds on the way to sat) at the very location of the receiver. To get this, you need... a reference receiver, so we are at D-GPS again. /j ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
GPS -- AGPS
Hi, Maybe I missed somehting, but to my knowlegde the AGPS is not yet working on the Freerunner. Is there any work being done to get AGPS working? Does anybody have an idea if it will ever be implemented or not? And if it will be implemented, when will it be ready? y _ De mooiste afbeeldingen van Angelina Jolie vind je met Live Search http://search.live.com/images/results.aspx?q=angelina%20jolieFORM=MIINTM___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: GPS -- AGPS
Not working yet, but we're working on it: http://www.mail-archive.com/community@lists.openmoko.org/msg17058.html Released as soon as it's ready at: http://openarchaeology.net If you'd like to contribute please feel free :) Joseph 2008/6/4 Yorick Matthys [EMAIL PROTECTED]: Hi, Maybe I missed somehting, but to my knowlegde the AGPS is not yet working on the Freerunner. Is there any work being done to get AGPS working? Does anybody have an idea if it will ever be implemented or not? And if it will be implemented, when will it be ready? y Plan je evenement, nodig mensen uit en deel je foto's met Windows Live Events ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: GPS -- AGPS
Yorick Maybe I missed somehting, but to my knowlegde the AGPS is not yet working on the Freerunner. Is there any work being done to get AGPS working? Does anybody have an idea if it will ever be implemented or not? And if it will be implemented, when will it be ready? Len Chen sent a pdf to the list last month with gps comparisons. The last paragraph of his writeup seems to suggest that freerunner's implementation of the gps module lacks the ability to do agps. -- Brad ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
Re: GPS -- AGPS
Yorick Matthys wrote: Hi, Maybe I missed somehting, but to my knowlegde the AGPS is not yet working on the Freerunner. Is there any work being done to get AGPS working? Hi Yorick, There are two approaches of A-GPS supporting of ublox4 chip which are on-line mode and off-line respectively. But we only could support on-line mode since we don't have internal flash to store off-line data. Currently, the implementation of A-GPS with on-line approach is almost ready. I'll commit the code today. Cheers, Matt Does anybody have an idea if it will ever be implemented or not? And if it will be implemented, when will it be ready? y Plan je evenement, nodig mensen uit en deel je foto's met Windows Live Events http://events.live.com ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community ___ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community
