Slow GPS Fix

[fychan]

Hi Guys,

I noticed my GPS takes about 30s ~ 1 minute to get its Satellite positions verified.
Is this normal? However, it takes < 4s if your are at the same position.

I read about the Artemis having a QuickGPS software that download satellite information periodically from HTC to quicken the GPS fix process.

Anyone can dump this software to see if it works for the Trinity?
I manage to get the QuickGPS meant for HP GPS phones... but dun see much improvemet.

Artemis is using SirfIII chipset.... anyone has both devices with them to advise if its any better compared to the Trinity?

Does anyone knows if QuickGPS will work only with any particular chipset?

Regards
Fei Yu

[psargent]

There is a post from someone who owns both in the middle portion of the GPS test rom thread.

I own both as well, but I have been reluctant to try the test rom on my trinity with the imminent release of the official HTC GPS rom. I have also posted a couple of times already with the same question as to whether Quick GPS would work with Trinity or would be included in the official rom update.

If someone would instruct me on how to dump the program from the Artemis, I would be happy to do it. Post here or send me a PM if you want to provide instructions.

[forcedalias]

Turn left at the lights you passed 30 seconds ago.

[Guybrush]

the p3300 use a technology called SiRF InstantFix. I don't think there's something like this also for qualcomm chipset.

[psargent]

the p3300 use a technology called SiRF InstantFix. I don't think there's something like this also for qualcomm chipset.

Thanks for the info...I remember reading about this - I just didn't know it was proprietary. Kinda hoping it was code that could be applied to any GPS receiver. Oh well...

[DarkStar69]

According to Qualcomm their GPS implimentation, gpsOne, has a number of GPS "modes":
Standalone GPS: The GPS receiver calculates a position without using any assistance data and without a connection to
the wireless network.
MS-Based: The GPS receiver calculates the position using assistance data from a location server to increase cold-start
sensitivity and reduce the start time for an initial position calculation.
MS-Assisted: The GPS receiver uses assistance data from a location server to make measurements related to its distance
from the GPS satellites, then sends this information to the location server where the position is calculated. This mode also
increases cold start sensitivity and reduces the start time for an initial position calculation.
MS-Assisted/Hybrid: Wireless network information is added to GPS measurements as part of the position calculation by
the location server, integrating the relative strengths of GPS information and available wireless network location information
for increased positioning reliability in difficult GPS environments.

In their specs they claim:
•Accuracy 5-15 meters in assisted modes, open sky
•TTFF processing time 2-10 seconds in assisted modes, open sky
•Sensitivity of existing or planned devices varies from -154dBm to -160dBm in assisted modes depending on phone parameters and chip implementation

It seems that as long as your provider has implemented the "assist" functionality in their network you will get fast fixes. Not sure if QuickGPS or something like it would have any positive impact on TTFF. Might be an opportunity for a enterprising software developer.