GPS problems in general (independent of ROM)

[Guest kilian27]

Hi everyone!

I tried several ROMs but still have problems with GPS. As there are some similar user reports in different threads here and there, I would like to suggest to bring together these discussions in one thread.

The problem with my GPS is, in general, that there is no fix or a very slow fix most of the time. I used the apps "GPS Test" and "GPS Status" for diagnosis. There are different scenarios:

(1) No satellites are found, thus no fix.

(2) Some satellites are found, often about 4-7, but GPS does not lock.

(3) Some satellites are found, GPS Test shows slightly varying signal strenghts for about 1 minute, but then freezes (application is still responding, but all the signal strenghts remain constant); no fix.

(4) About 10 satellites found and locked instantly within less than 10 seconds.

For example: Boot the phone -> case 4 (instant fix) -> reboot (whily staying at the very same position) -> case 1 (no satellites) -> reboot -> case 2 or 3 (no fix). Most time, I have case 1 or 2, while 4 is very rare. For case 2 and 3, GPS test shows a signal strenght of about 30-40 for all satellites, so right below the "green" level.

Another example: I get a fix within GPS test, then switch to GoogleMaps, but there the fix is lost and cannot be established again (GPS icon in status bar keeps flashing).

Use of A-GPS or deleting the GPS cache and downloading new data (which can be done in the GPS status app) does not change anything, nor does wiping the cache partition with Clockwork.

I tried this with different 2.1 ROMs and did not experience any difference. I have a slight feeling, that case 4 more often occurs right after flashing a new ROM, but this may be a conincidence.

Who else did experience such problems and was able to solve them? Do you suppose it is a hardware or a software problem? Any hints would be highly appreciated (I bought the phone on ebay in germany, so no warranty ...).

Thanks in advance and above all thanks to all of you contributing to this excellent forum!

kilian

[Guest ChundaMars]

I was having the exact same problem until a few minutes ago, then came across this: http://www.appbrain.com/app/gps-status-too...psim.gpsstatus2

Download it, install it and then reset A-gps data - works a treat!!!

[Guest oh!dougal]

First point - GPS is not designed to work indoors. If it works for you sometimes, then that's great - just don't EVER complain about it NOT working indoors! It doesn't work too well in forests either - wet leaves absorb the minute signals from the satellites!) And tower blocks reduce the amount of sky it can see without obstruction.

With a clear view of lots of sky, your phone can 'see' more satellites, and get stronger (less corrupted) signals from them.

More satellites and cleaner data makes for a faster, more accurate fix.

A related point is that being stationary definitely helps for getting the first fix. If you are moving, by the time your location has been calculated, its wrong!

Second point - Android/Google provides for "location info apart from GPS". For this, it uses Cell Transmitter ID (and thus location) plus wifi network location.

AFAIK our phones are constantly reporting back to Google what wifi networks they come across, and what cell towers are nearby, and even better, what GPS co-ordinates we were at when we encountered that wifi network -- so Google has a massive database recording what wifi name, within a particular tower's coverage, is where.

There may also be a dependency on your cell network having published complete (up to date) and accurate locations for its towers...

But this "pseudo-GPS" location-by-wifi works brilliantly indoors ...

Third point - Time matters. GPS location is about measuring minuscule time differences, but your phone 'knowing the right time' seems to be also used in the GPS computation for where satellites should be at a specific time - and getting that from an internet 'network time server' seems to help. And the closer the NTS (actually the less time wasted (and the less variation) in your datalink to the NTS) the faster your phone can get an accurate 'time fix'.

Fourth point - If you have "mobile data" and wifi turned OFF (or you are out of coverage), then ALL 'live' ASSISTANCE to getting a GPS fix is disabled. Your phone may know what cell tower it is linked to, but it can't download the tower's location.

If its your first fix since clearing data you won't even have a previous location to help.

If you've moved since your last fix, the old data won't be terribly helpful.

And you probably also won't have super-accurate time if you are out of coverage...

Fifth point - it is ONLY by using these 'assistance' tricks that GPS can get a fix in seconds (which we like) rather than in minutes (when we give up on it). Traditionally, GPS would distinguish between Hot, Warm and Cold starts ... http://www.gsmarena.com/glossary.php3?term=gps

And then there's "wiper". This seems to be Qualcomm's (the Blade's chip maker's own) network positioning system for GPS assistance (gpsOneXTRA). But it seems as though it doesn't work perfectly - at least in 2.2

However, the good news is that the phone seems to be able to do 'network location' even after wiper.apk has been deleted from the phone. Google's stuff seems to work fine.

Wiper may help some people and hinder others -- it may depend on the rom and the usage.

I've got it turned off in the gps.conf configuration file - with good results with Seb's DX2.

There is a thread in the roms section discussing using (and editing) an alternative gps.conf file. Certainly using an NTS that is at least in your own continent does seem to speed up GPS fixing.

The content of your current gps.conf file will depend on the rom you are using.

And clearing old (or corrupt) assistance data (with the GPS Status app) could be helpful too.

Edited February 16, 2011 by oh!dougal

[Guest Ricey155]

interesting read dougal cheers for sharing

my gps decided to stall friday never had issues with it, so im scanning for ideas, keep em coming :(

[Guest Skip Tracer]

I can vouch for the gpsstatus app (as noted by ChudaMars above) in the market as being very good.

I have a very old Garmin GPS II unit, E-Trex Summit and a couple of in car units and none of them can give a position when I am sat in my front room (2 storey semi, tiled roof) however unbelievable the SF has no problems at all logging on too at least six satellites, and no I don’t have “use wireless networks” ticked.

I know there not designed for use in doors but it’s a good indicator just how good the SF can be.

I have been gobsmacked to how sensitive the Blade is for GPS but then maybe I was just lucky with mine or perhaps the technology has just got better the past two years.

I have had no problems with GPS on Orange stock or JJ r9.

[Guest Ricey155]

I can vouch for the gpsstatus app (as noted by ChudaMars above) in the market as being very good.

I have a very old Garmin GPS II unit, E-Trex Summit and a couple of in car units and none of them can give a position when I am sat in my front room (2 storey semi, tiled roof) however unbelievable the SF has no problems at all logging on too at least six satellites, and no I don’t have “use wireless networks” ticked.

I know there not designed for use in doors but it’s a good indicator just how good the SF can be.

I have been gobsmacked to how sensitive the Blade is for GPS but then maybe I was just lucky with mine or perhaps the technology has just got better the past two years.

I have had no problems with GPS on Orange stock or JJ r9.

im using the same rom just cleared the cache and its back working again so all good, great device - my endomundo app works excellent with my road bike or hiking etc can't fault it

[Guest gwebb]

I also recommend GPS Status, and have a look at GPS Test Plus as well. They are two very good apps, both are cheap as chips, and well worth having if you use GPS a lot.

Take a look at the free versions, but if you use them please support the developers.

GPS Status & Toolbox

https://market.android.com/details?id=com.e...psim.gpsstatus2

GPS Status - donation

https://market.android.com/details?id=com.e....gpstoolbox.pro

GPS Test

https://market.android.com/details?id=com.chartcross.gpstest

GPS Test Plus

https://market.android.com/details?id=com.c...oss.gpstestplus

[Guest Hirsel]

Hi,

I just had the same issue with a ZTE Balde on Swedish Spring and the solution above (delete cache with the GPS Status app) worked like a charm! Great App!

cheers,

Hirsel

[Guest leighw101]

I've got exactly the same problem with my ZTE Racer.

The other half has one in white that has been upgraded to the same rom as mine but mine still won't pick up any satellites at all where hers will every time.

The most I ever managed using GPS Test is to get 1 sattelite in view.

I've tried all the things with fasterfix but still no joy at all even after resetting the agps cache.

Anybody else had any other ideas? The rom I'm currently using is the 2.3.2 rom from on this forum but it did the same on 2.2 as well so it's definitely not rom dependent.

Edited June 22, 2011 by leighw101