N900's Sat Nav - maemo.org

martyk69uk | # 1 | 2012-08-27, 10:49 | Report

Hi people.

Cant seem to get a decent signal on my N900.

It comes and goes and keeps saying 'waiting for signal'

ive set the properties to find supl.google.com

Using Sygic Maps.

I'm in the UK with it right now and can't seem to get a valid gps signal and when i do it dies so quickly.

Is there any additional software i need to boost or anything i need to enable/disable?

Thanks people.

The Following User Says Thank You to martyk69uk For This Useful Post:
Wikiwide

ajack | # 2 | 2012-08-27, 11:46 | Report

Happens to me a few times also. A restart usually solves the problem...

The Following User Says Thank You to ajack For This Useful Post:
Wikiwide

arne.anka | # 3 | 2012-09-22, 20:08 | Report

gpsjinni is said to help -- start it and wait for a fix.
for me, though, only using internet assistance works (which usually mean added costs. thanks a lot, nokia).

The Following User Says Thank You to arne.anka For This Useful Post:
Wikiwide

rotoflex | # 4 | 2012-09-23, 09:09 | Report

My N900 can sometimes take three or more minutes to get a satellite lock.

The Following User Says Thank You to rotoflex For This Useful Post:
Wikiwide

Wikiwide | # 5 | 2012-09-23, 12:27 | Report

Quick reply...
GPS errors are affected by geometric dilution of precision and depend on signal arrival time errors, numerical errors, atmospherics effects (like, clouds), ephemeris errors, multipath errors (reflecting from buildings) and other effects. But these circumstances affect both getting GPS lock and maintaining a good reading of GPS signals, right? So why is getting satellite lock taking so long?
It's not simply matter of listening for all thirty two satellites instead of four or five of them. It's not even the fact that the receiver looks for each of the currently unavailable, far away, satellites, sifting through 1023 cases. It's the matter of long navigation message, containing the almanac - so that the receiver could decide which satellites can be contacted, and which cannot - and the ephemeris - satellite's position. The navigation message itself is constructed from a 1,500 bit frame, which is transmitted at 50 bit/s. Each frame contains only 1/25th of the total almanac. At this rate, 12.5 minutes are required to receive the entire almanac from a single satellite.

Originally Posted by

If no stored or valid satellite almanac data are available, the GPS receiver starts to search the sky attempting to locate and lock onto any satellite in view. Depending on the receiver search strategy and on the actual satellite constellation, this process may take 15 -60 minutes.

So, don't blame the hardware - blame lack of information. Fortunately, the almanac is valid for long time periods (up to 180 days). So GPS lock should be faster next time, once you have downloaded it the first time.
I have not ever used network-assisted GPS - I avoid cellular-network-based-Internet at all costs. I consider GPS on N900 adequate, even if it doesn't miraculously give me my location in the first five seconds after the request. Though, I have not actively used it lately.
Best wishes.