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| gpspassion |
Posted - 02 janv. 2008 : 19:57:42
  
Autonomy/SIF v2 in action : 29 ephemeris sets calculated
GPS SYSTEMS WITH Auto-AGPS - 20081023 :
- Garmin Edge 605/705 Bike GPS (SIFv2 - with v2.20)
- Garmin nuvi 2x5 (STM/Rx Networks GPStream)
- Garmin nüvi 5xx (STM/Rx Networks GPStream)
- Garmin nüvi 7xx (SIFv2)
- Garmin nüvi 7x5 (HofFix with MTK v1 chipset)
- Garmin nüvi 8xx (HofFix with MTK v1 chipset)
- Garmin Oregon (STM/Rx Networks GPStream)
- HP iPaq 310 (Centrality Titan Chipset with Autonomy)
- Medion P4425 (Centrality AtlasIII chipset with SIF v2 - available with latest ROM update)
- Navigon 1210, 2210, 7200/72100 (SIF v2)
- Mio Moov 200 and 300 (SIFv2)
- Becker Z-101 and Z-200 (SIF v2)
- Navman S30/S50 3D - (SIFv2 - UK Only ?
News item on the portal
SiRF have just announced SiRFInstantFixII for faster GPS acquisition. Compared to SiRFInstantFix v1 (SIF v1) launched in early 2006 and used very effectively on the TomTom GO systems, as seen in this comparison, and the Mio and Eten GPS PDAPhones, the predicted ephemeris data is no longer downloaded over the internet but generated directly by the GPS system for full autonomous use. This is of course reminiscent of the "Autonomy" technology by Centrality (they were bought by SiRF in June 2007, see news) and released for the first time on the HP iPaq 310 with good results.
Why use "Ephemeris APGS" ?
The idea behind "Offline AGPS" (vs SUPL AGPS) 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 over the internet. 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.
SiRFInstantFixII vs SiRFInstantFixI - Pros and Cons...
On paper it would seem that having the GPS generate ephemeris data in an autonomous way is better than having to download it over the internet as with SIF v1, but the catch, at least with Centrality's "Autonomy", is that you need to use your GPS regularly as the predicted ephemeris data is only valid for 3 days. Once the data has expired you'll need 24 hours for new data to be generated and in the meantime the fix will have to be done the "old-fashioned way" by downloading the live ephemeris data from the satellites with the usual constraints (30 seconds minimum, need good signal >28db-Hz, no blockage, etc...). On the other hand with SIF v1 you can pick up your GPS after a four day break, download the ephemeris data from the Internet and get a quick fix.
We'll have to see if there are hybrid v1/v2 versions of SIF, but based on the PR it doesn't seem to be the case.
FULL PRESS RELEASE : >> LINK << :
SiRF's InstantFixII GPS Technology Eliminates PND Start-Up Wait
Mobile Navigation Devices Can Have Start-Up Times As Low As 5 Seconds
Without Requiring Any Network Connectivity
SAN JOSE, Calif., Jan. 2 /PRNewswire-FirstCall/ -- SiRF Technology
Holdings, Inc. (Nasdaq: SIRF), a leading provider of GPS-powered location
platforms, today introduced SiRFInstantFixII, an autonomous version of
SiRF's original SiRFInstantFix technology that is designed to significantly
improve the start-up times of portable navigation devices (PNDs) and other
mobile navigation devices without needing any network connectivity for
assistance or updates. Available now for both SiRFstarIII GPS receivers and
SiRFatlas and SiRFtitan multifunction SoC navigation processors,
SiRFInstantFixII achieves GPS start-ups in as little as five seconds so
that mainstream consumers can begin navigating as soon as they're ready to
drive.
"Our groundbreaking SiRFInstantFixII technology makes the frequent
start-up waits for PNDs a thing of the past," said Kanwar Chadha, founder
and vice president of marketing for SiRF Technology. "By not requiring any
network connectivity or downloads, it significantly improves the daily
navigation experience for consumers of mobile navigation devices..."
Questions, comments? |
| 15 L A T E S T R E P L I E S (Newest First) |
| gpspassion |
Posted - 13 déc. 2009 : 20:05:24
Welcome to the forums. Yes, most recent AIOs have SIFv2. |
| navravk |
Posted - 13 déc. 2009 : 19:15:58
Apparently, Navigon 2200T has a SIF2 (SiRF GRF3i+ GPS chip plus InstantFix II) |
| gpspassion |
Posted - 01 mars 2009 : 13:13:55
No and I don't think we'll ever see one because SIF v2 requires a lot of computation power that is not available in a simple receiver.
There are receivers with SIF v1/"AGPS over the Internet" though like the latest MTK v2 based Qstarz -> http://www.gpspassion.com/forumsen/topic.asp?TOPIC_ID=47602 |
| rybshik |
Posted - 01 mars 2009 : 06:17:31
Is there any stand-alone USB GPS receiver with SIF v2 on the market yet?
If not, what would the best USB GPS receiver as far as start-up time and sensitivity to weak signal are concerned? |
| gpspassion |
Posted - 12 oct. 2008 : 23:47:43
Thanks, any more details on what SIFv2.1 does ? |
| btekcan |
Posted - 12 oct. 2008 : 20:20:14
Please update 1st post again.
- Next YE-G 828 (SIFv2.1)
- Next YE-G 708 (SIFv2.1)
Both models sale in Turkey market..And supported from NavNGo support site www.naviextras.com and product home page is www.nextnavigasyon.com (Turkish now but will be supported English soon)
Thanks
|
| gpspassion |
Posted - 09 oct. 2008 : 12:36:12
First message updated :
- Garmin nüvi 5xx (STM/Rx Networks GPStream)
- Garmin nüvi 7x5 (HofFix with MTK v1 chipset) |
| gpspassion |
Posted - 25 août 2008 : 20:20:33
Well 3/4 seconds can only be in a perfect environment, not in a dense urban environment behind a coated windshield. Always best to the conditions not to confuse readers ;-) I've also heard about a new version of SIF that would make devices compatible with both SIFv1 and SIFv2, that might be it.
Anyway, I was actually referring to a link for the devices. |
| btekcan |
Posted - 25 août 2008 : 20:00:58
[SNIP]
New technology use different algorithm.But I haven't got more info now.I hope next week I'll get the detailed info.
New version create a NVM3 files without any extensions,and this file header start with SIF2.1.04-WinCE-ARM-FF4-19 many device use SIFv2.0 now.But this is very new.
I cannot compared because I haven't got any SIFv2 device.But these device has maximim 3-4 seconds fixed (if satellite more than 6) |
| gpspassion |
Posted - 25 août 2008 : 13:05:41
Interesting, got a link ?
What is SIFv2.1 compared to SIFv2 ? |
| btekcan |
Posted - 25 août 2008 : 09:08:29
- Next YE-G 828 (SIFv2.1)
- Next YE-G 708 (SIFc2.1)
Both models sale in Turkey market..
Thanks |
| gpspassion |
Posted - 04 août 2008 : 10:53:29
List updated on the first page :
GPS SYSTEMS WITH Auto-AGPS - 20080804 :
- Garmin Edge 605/705 Bike GPS (SIFv2 - with v2.20)
- Garmin nuvi 2x5 (Rx Networks GPStream)
- Garmin nüvi 7xx (SIFv2)
- Garmin nüvi 8xx (HofFix in theory but MTK chipset with no AGPS ?)
- HP iPaq 310 (Centrality Titan Chipset with Autonomy - available)
- Medion P4425 (Centrality AtlasIII chipset with SIF v2 - available with latest ROM update)
- Mio Moov 200 and 300 (SIFv2)
- Becker Z-101 and Z-200 (SIF v2)
- Navman S30/S50 3D - (SIFv2 - UK Only ? |
| gpspassion |
Posted - 11 juin 2008 : 11:16:11
Yes, so use the good old tricks that were a requirement with the Magellan and Garmin receivers of the 90s, now it just speeds things up : turn on your GPS in unobstructed area, back facing up, don't move it. Should always get a fix in 60 seconds, tops. |
| adp |
Posted - 11 juin 2008 : 08:10:54
"drives a car with a coated windshield in an urban environment"??? Nah, I never do that....
:-(
yes, the webupdater was out of frustration
still trying to figure out the best approach for the casual user.
My casual use related issues are compounded by me turning it off at location 1 on day one, and then the next time I turn it on is Day 10 and I am in a different location. That's gonna take some time to find the stas, I am guessing. |
| gpspassion |
Posted - 02 juin 2008 : 21:28:55
Interesting, actually these seem to be Mio Moov devices sold under the Navman name, which makes sense since Mio said they would be keeping the Navman name in a few countries, including the UK.
An interesting addition to the list, the Garmin Edge 605/706 Bike GPS systems http://www.gpspassion.com/forumsen/topic.asp?topic_id=107654#750749 ! Based on it's stellar TTFF performance, this addition makes me even more confident that the Forerunner 405 GPS watch also uses SiRFInstantFixII and since it's a watch that is always on (battery life in sleep mode is 15+ days), the SIF v2 crunching can take place continuously, either that or it uses the "push to fix" mode to update the ephemeris data every 30 minutes. |
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