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|T O P I C R E V I E W
||Posted - 26 janv. 2006 : 02:00:30
Mio A701 : 1. "synthetic" (SIF only) Warm Fix 2. "Mixed Fix" -> details
News Item on the portal
The idea behind "Offline AGPS" (or "AGPS over the internet") is straightforward but effective : instead of downloading the ephemeris data from the satellites, something that takes 30 seconds at best, requires a good signal level (>28 dB-Hz) and needs to be done every 4 hours, you download a 50kb ephemeris file valid for 3/7/10 days. Acquisition time in the morning goes down to 10 seconds from 40 seconds in good environments and remains at 20/30 seconds on average in challenging environments (coated windshield, dense urban environment) versus several minutes, if at all possible, without AGPS.
When you turn on your AGPS enabled GPS receiver, synthetic ephemeris data is used first and then there is a gradual switch to live ephemeris data as it becomes available (30 seconds in a perfect environment). Once live data has been downloaded it is valid for about 4 hours and it gets updated continually, but if you turn off your receiver for 4 hours, then you start from scratch again.
LIST OF COMPATIBLES DEVICES - December 5th, 2008
- Globallocate's LTO :
- GPS PDAPhones : HP hw6515 and HP hw6915 - GL20000 chipset
- AIOs : TomTom ONE v3/v4, TomTom ONE XL v1/v2 - Hammerhead chipset - review
- Nemerix's NeX : no systems so far
- Qualcomm gpsOneXTRA (see PDF documentation) : 40Kb file valid for 7 days, provides for very fast warm TTFF, about 8 seconds with a good view of the sky and as low as 20 seconds in dense urban environments, as tested on the HTC TyTn II - see topic for more details.
Also on Samsung i780, HTC Touch Cruise, HTC Touch Diamond
- SiRF's SiRFInstantFix v1 :
- GPS PDAs : Fujitsu N560
- GPS PDAPhones : Asus P750, Eten G500/X500/X500+/X800/X600/X650/M700/M800/M810, HTC P3300/X7500, Mio A701/A501/A702
- AIOs : Asus R300/R700, TomTom ONE v1/v2a, TomTom GO x10/x20/x20/x30/x40, Dash Express
- MTK v2 (MTK 3329) company site : iBlue 747A+, Qstarz Q1000X, Qstarz Nano - Bluetooth GPS dataloggers
- Skytraq AGPS : Wonderpoud BT100Y and BT760Y - Bluetooth GPS receivers - see this topic
- uBlox AssistNow® Offline : no systems so far
Updated September 2007 : Skytraq AGPS available on Wondeproud Bluetooth receivers, more details >> here <<
Updated March 2007 : NemeriX launched NeX in February at 3GSM, more details >> below <<
Updated January 17th, 2007 : Nearly a year after SiRF, uBlox are also launching their "AGPS over the internet" solution, called AssistNow® Offline. In the same way as Globallocate's LTO and SIRF's SiRFinstantFix, the idea is to predict the orbit of the GPS satellites to speed up the time to first fix in the morning and in difficult environments (urban canyons, coated windshield, indoors, etc...). They're going one step further though with a lifespan of 14 days versus 10 for Globallocate and 7 for SiRF and there will be a free version and a premium version. uBlox chipsets are not currently used on consumer GPS systems, but their SuperSense enabled Antaris 4 will power Navigon's upcoming Porsche Design 9611 AIO.
Updated June 14th - SIF (SiRFInstantFix) that works wonders on the Mio A701 as Globallocate's LTO does on the HP hw6515 will also become available on the Eten G500 via a ROM upgrade (see below) during the summer. At the 3GSM show, Fujitsu also mentioned SIF for the Loox T830 announced for this summer as well. On the other hand, TomTom is still showing it as being "available soon" although the GO x10 series have been available for a couple of months now. Let's stay tuned for more...
According to their website and based on testing of the shipping x10 series, TomTom has postponed the launch of QuickFix.
SIF is deployed on the Mio A701 GPSPDAPhone though, see the review for more details.
Yet another system applet ? No, because Quick Position lets you download the SiRF ephemeris data, and can remind you to update too
At the end of January, SiRF announced SiRFInstantFix (SIF), an AGPS over the internet solution to speed up the first time to fix and in some cases make it possible, like Globallocate's does on the HP hw6515. We now have some more information about it:
There is no planned upgrade path for existing SiRFstarIII based systems unfortunately
First PDAPhone with SIF: Mio A701 with "Quick Position"
First AIO with SIF: TomTom 510/710 and 910, with "QuickLocate"
The TomTom .ee file weighs about 57Kb for a 7 days lifespan
On the SiRF simulators at the 3GSM show, a "warm" fix took about 13 seconds with SIF vs 40 withough it.
Unlike Globallocate's solution that can get a fix without satellite time, SIF, needs at least one satellite in view with a decent level of signal (142dBm) to get the time. According to SiRF this is achievable in almost all environments.
I'm looking forward to the first live testing with either the Mio A701 or the new TomTom 910 to see how it improves the user experience as much as Globallocate's LTO on the 6515.
Activity is clearly ramping up in the field of A-GPS over the internet with the recent announcement by u-Blox of their own solution. After Globallocate's LTO implemented on the HP hw6515 (see the full review), SiRF's announcement of SiRFInstantFix, this is the third A-GPS via the internet solution that relies on the prediction of ephemeris data to make the initial "fix" nearly instantaneous. This makes sense as live ephemeris downloading has now become the most time-consuming element (30 seconds) with powerful chipsets that can compute a fix very quickly once that hurdle has been overcome. The only consumer solution currently based on a uBlox chipset is Socket's V2 Bluetooth GPS.
Hot off the wire, SiRF have just announced the launch of SiRFInstantFix, a "unique service that minimizes the start-up wait time for GPS systems. SiRFInstantFix provides consumers with the ability to turn on their SiRF-based navigation devices and achieve the first fix in as fast as eight seconds...SiRFInstantFix eliminates the initial time-consuming task of obtaining precise GPS satellite location data -- ephemerides -- from the satellites themselves. Instead, the SiRFInstantFix server uses a sophisticated set of proprietary algorithms to predict seven days of ephemerides and distills them down to a small file which SiRF-based navigation systems can use to pinpoint every GPS satellite".
Not that it's related, but it seems my wish of seeing a GPS solution combining the power of SiRFstarIII (tracking down to 14dBhz or -159dBm) and the LTO (Long Term Orbit) technology of Globallocate (website), first used on a consumer device on the HP hw6515, to overcome the physical requirement of a minimum and uninterrupted signal level from the satellite of 28dBhz to download ephemeris data, is about to come true. Great news for the end user, although one has to wonder how SiRFInstantFix will play along with Globallocate's LTO/"Extended Ephemeris" patents that seem to cover this field. The PR does not mention any cooperation between the two companies.
According to the PR, SiRFInstantFix is "available now", but it is not clear if and which current SiRFstarIII based devices can benefit from it or whether an upgrade will be required or available.
Here is a real life example of the impact of using stored ephemeris data, the other day I couldn't get a fix with my SS3 based RBT-2010 waiting for my plane to take off to update my position on my tracking server because my ephemeris data was outdated (> 5 hours) and the signal level was below 28dBhz, meaning no fresh ephemeris data download, so I took out my 6515 and it was able to get a fix thanks to the data stored in its memory. What's appealing with SiRFIII is that it can track down to 14dBhz while I haven't seen the 6515 go below 22/23 dBhz.
On the left the SiRFstarIII RBT-2010 sees 11 satellites but signal level is too low to download ephemerides, so no fix
On the right the Globallocate 6515 sees fewer satellites but relied on its stored ephemeris data to get a fix
Reported dBhz levels can vary but tests done within a few seconds
We'll have to see how low a SiRFIII GPS can get a fix with SiRFInstantFix, probably won't be as low as 14dBhz, but it's bound to be a massive improvement compared with the current 28dBhz, even if it's say 20dBhz that would mean getting a fix with signal that is 6 times weaker.
Questions, comments ?
Discounts and Assistance/Réductions et Assistance (Club GpsPasSion) / Où commencer?
|15 L A T E S T R E P L I E S (Newest First)
||Posted - 20 mars 2011 : 02:38:57
Welcome to the forums.
Must admit I stopped worrying about AGPS on my dataloggers a while ago ;-) Good question though, but I'd suggest reposting it in the topic dedicated to the MTK chipset -> http://www.gpspassion.com/forumsen/topic.asp?topic_id=81990
||Posted - 20 mars 2011 : 02:01:51
Are all MTK v2 (MTK 3329) devices AGPS compatible? I noticed some MTK v2 (MTK 3329) based dataloggers have no mention of AGPS in their product manuals. Do 3rd party tools such as bt747 allow MTK v2 (MTK 3329) based dataloggers to upload AGPS data? Where do you aquire AGPS satellite data. I'm new to the GPS devlopments of the last 10 years.
||Posted - 01 mars 2009 : 17:04:00
Please recommend a good stand-alone GPS receiver with USB interface.
||Posted - 01 nov. 2007 : 15:35:10
Thanx for the quick reply.
But still I cant find the menu to load the file into the app.
But anyway, I dont need to see the Purples, I just want to know hot to set up my device to be able to use SIF. (when it has the ability, why not to use it)
What is the most gentle way to set up virtual COM4? I searched the miousers forum and got a lot of information, from which I am more confused than before...
||Posted - 01 nov. 2007 : 15:11:28
You need to load the ephemeris file specifically in the app, second menu if meomory serves.
||Posted - 01 nov. 2007 : 15:01:56
Can you pls. give me a hint how to setup my A701 to get the "purples"?
I'm using the GSP Settings to choose the hardware port and the program port. I dowloaded the emphersis data, but after the start, I only get blue after a while, no purples.
Where's the problem?
4700,5550,3970;BT-338,10Deluxe,Brodit Active;TomTom5,AutoMapa (PL),GPMapa (PL)
||Posted - 20 sept. 2007 : 20:04:33
Qualcomm : HTC 4550/TyTn II/AT&T 8925/Kaiser - 6 day autonomy - "The GPS Quickstart program comes loaded in the programs folder and it has only 3 settings, 1-Remind Me when data expires, 2-Auto download when data expires, 3-Auto download when connected to a PC via activesync. The prog downloads about 6 days of satellite data from the internet to speed the fix and is basically invisible." - see topic for more details.
||Posted - 12 sept. 2007 : 02:12:22
Feels a bit lonely here ;-)
Updated September 2007 : Skytraq AGPS available on Wondeproud Bluetooth receivers, more details >> here <<
||Posted - 07 sept. 2007 : 03:31:02
"On-Board" A-GPS, i.e. no need to connect to the internet, is set to debut on the new iPaq 314, more about it here http://www.gpspassion.com/forumsen/topic.asp?TOPIC_ID=96776 courtesy of Centrality's "Autonomy".
||Posted - 13 juil. 2007 : 06:19:47
Saw that announcement, but I'm not sure what's different from January ? I guess it was in beta at the time.
||Posted - 13 juil. 2007 : 02:59:58
I don't know if this has been discussed but u-blox is now offering their AssistNow® A-GPS services free.
||Posted - 14 mars 2007 : 23:18:30
Good point, I added the link ;-)
It works on the Eten M700 so the X500 should be ok too. Just make sure to do a "factory reset" when you exit the program as switching back to NMEA put the GPS module in a "loop" and I had to take the battery out for 24 hours to get it back !
||Posted - 14 mars 2007 : 23:10:14
Originally posted by gpspassion
SiRF has recently made a new version of the SiRFdemoPPC tool available with support for SiRFinstantFIX and it's interesting because it shows the satellites that use synthetic ephemeris (purple) and those that have live ephemeris (green).
Ooh, I know this is an obvious question BUT...
How to download, please ? I'm using an ETEN X500 and I'd like to use this.
||Posted - 13 mars 2007 : 12:15:31
SiRF has recently made a new version of the SiRFdemoPPC tool available with support for SiRFinstantFIX and it's interesting because it shows the satellites that use synthetic ephemeris (purple) and those that have live ephemeris (green). Here is an example with a warm fix on the MIO A701 GPS PDAPhone, TTFF happens in 12.1 seconds and after about 20 seconds some live ephemeris data has been downloaded :
Warm Fix -> TTFF : 12.1 --- ~20 seconds --->
||Posted - 13 mars 2007 : 12:13:13
NemeriX launch NeX
NemeriX launched their own extended ephemeris solution at the 3GSM Show in Barcelona in February 2007. I was able to try it on the demo machines and even in the degraded environment of the hall it was able to achieve a Warm TTFF of about 10 seconds, similar performance to LTO and SIF and better than AssistNow (about 20 seconds on the Socket BT GPS). They claim it can work for up to 21 days (SIF is 7 days, LTO 10, AssistNow 14).
The Full PR is on their site.
"NemeriX launches NeX Extended Ephemeris Solution
- Delivers twice the location accuracy of competing solutions
- Time-to-first-fix in less than one-fifth the time
- Innovative implementation allows transmission over a multitude of media
- Offered free as part of the NemeriX GPS solution"
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