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Developing a GPS application - some questions

Hi
I'm developing a GPS application to assist devices with onboard GPS chips (eg. Trinity) to obtain a fix faster.
My application works fine thus far, however I have a question in regards to TomTom. Every other application works instantly, ie. they report the fix obtained as "Valid" and start displaying the location on their GUI almost instantly.. EXCEPT for Tomtom.
Does anyone know what TomTom looks for other than a 2d/3d fix? It detects its receiving information yet hangs on "Lost GPS signal since xxx seconds" for around 2-4 minutes and THEN it starts working fine.
I'm confused as to why this is only happening with TomTom so any information you guys have would be greatly appreciated.

I'm not sure what your application does to assist, or which other applications work fine. But I'll take a guess. Tom-Tom is a stand alone GPS app and the others use assited GPS?
Satellites transmit ephemeris data, data about the orbit of the GPS satellites, every 30 seconds. Tom-tom must lock on to the salelliites and wait a minium of 30 seconds to recieve this data. If the other GPS applications use assisted GPS, they get help from a location based server (LBS) run by the cellular provider. The LBS sends the ephemeris data and other data to help the GPS lock onto the satellites quickly, so the GPS doesn't have to wait.

Interesting GPS issue...

Has anybody noticed that if you use the gps status app before you use the google maps that the gps connect quicker for any app using gps such as maps, weather, where, etc... until phone reset.
When I run google maps first gps would just search for several minutes and sometimes wouldn't even find the location. So for anyone with gps issue probably try the gps status app from the market first.
I'm wondering if the gps status and google maps access the epic 4g gps differently... just a thought
Sent from my SPH-D700 using XDA App

I did what you suggested and indeed the gps locked much faster on google maps when I used GPS status first.

three epics here. extensive GPS testing over weeks now.
what you are seeing is gps status forcing aGPS vs "use wireless location, whcih is not aGPS.
If your ephemeris is new or has been cleared (the Epics main problem is not clearing ephemeris) you get an aGPS lock in seconds on GPS/aGPS only application like GPS status. But on application that can use either location method, the non GPS Use wireless networks" or the GPS, it often tries to get a wireless tower location first.
I get the identical affect by turning off the tower based system by keeping "Use wireless networks" normally off. this gives me instant aGPS locks five to ten seconds in proper conditions at all ties with cold start enabled.

[Q] GPS hot fix technology exist on android??

Hi guys,
I have some trouble with GPS, it's take very very very long time to establish appropriate connection to some satellites. On Windows mobile there was app which download data about positions satellites from INTERNET and speed up the connection process. Then have exist some this solution for android platform? and one more thing, have some soft which can show satellites connected etc (not need any navigation or compass just some thing for verify)..
Any ideas?

Volis said:
Hi guys,
I have some trouble with GPS, it's take very very very long time to establish appropriate connection to some satellites. On Windows mobile there was app which download data about positions satellites from INTERNET and speed up the connection process. Then have exist some this solution for android platform? and one more thing, have some soft which can show satellites connected etc (not need any navigation or compass just some thing for verify)..
Any ideas?
Click to expand...
Click to collapse
Search for "gps.config"!

Download tis app called gps status...you can download satellites thru its settings or you can reset ur gps data in it...downloading agps data dramatically improves locking speed..check it out...hope it helps
Setings> GPS&Sensors > Auto-download agps data

I am having issues with some builds sometimes to get a fix.
Some android builds make WM GPS not to fix anymore even. The only way to make it work on WM again is to re-flash your radio and not run android again (Android seems to do something to the GPS that makes it stop working on WM).
Perhaps I am wrong but this is my observation.

nuclearfissure said:
Download tis app called gps status...you can download satellites thru its settings or you can reset ur gps data in it...downloading agps data dramatically improves locking speed..check it out...hope it helps
Setings> GPS&Sensors > Auto-download agps data
Click to expand...
Click to collapse
Yep looks that..

Thanks, it worked very well for me.

I have also raised this question previously.
With GPS's there are two additional technologies that help with speeding up a lock.
The first often known as QuickGPS. Normally when you GPS finally find its first satellite it needs to download a lot of satellite information including where all the other satellites are in relationship. This can take a minute or so and if it is interrupted will need to restart. Thats why you get a quicker lock when stationary versus moving. What QuickGPS does is download this information via the internet and store it locally.
The second is A-GPS. When your GPS starts it is listening trying to find anyone of over 30 satellites. This can take time. Once it find one satellite it then needs to repeat for another 2 before being able to identify where it is and what other satellites are in the area (From Step 1). What A-GPS does is find out where you are via cell sites etc. Once it has an approx location it then refers to the QuickGPS data to then workout what satellites are in the area. In then proceeds to only try to lock on local ones which is a lot quicker.
All the fixes for the HD2 gps relate to updating the NTP server setting in the GPS conf file. The current setting is fine however refers to an american time server. End of the day it is still going to give you a time sync to within a few milliseconds. Refering to a local NTP (Time Server) will give the exact same data.
Waste of time.
I believe the slow GPS lock is due to one of these technogies not working. I suspect it is a-GPS however have yet to confirm either way that the GPD data is being downloaded and saved in the right place.
Hope this helps.

Yes, I thinking primary about the fist option QuickGPS.. I was able on my HD2 wit win get the GPS lock for 7-10 satelelites in let then 30 second.. without that 5-10 minutes, then I thing is very userfull to have it somehow working on android too..

[Q] GPS Signal loss when data connection is on

Hello,
I have a strange issue with my HD2.
If I turn on data connection on, I can't get a steady GPS fix. I loose it all the time during several minutes.
If I turn off data connection, I don't loose GPS signal, but I can't use Google Navigation, Waze, ABonEntendeur... and all other tools which needs data connection.
I'm using Tytung's GPS libraries (V2.1 RPC) on a Runnymede version.
I'm using the marc's 0.1.8 kernel with MagLoader
I tried and turned on Wifi, Data and GPS. As long as I was connected to Wifi hotpost, I didn't loose the GPS signal. I went outdoor, I lost Wifi signal, data connection turned on, I lost GPS signal and didn't get it anymore !
Where should I start from to troubleshoot that issue ?

Same here, with TBD Sense 3.5 and also with Dorimanx latest CM7.2 ROM.
Issue seems to be unfixed atm.

I finally installed a Cyanogen 9 ROM...

GPS signal lost when mobile data is enabled

HTC ONE M8
Custom ROM android 9 lineage OS 16.0
I have noticed problems with the GPS on my device. Google Maps and Waze many times the GPS signal drops and can not determine the location.
In my test I could find that the GPS problem happens when the Mobile Data are active. Just disabling mobile data and GPS back to work with good accuracy and even on rainy days.
If I connected to WiFi and mobile data is disabled GPS working normally.
I researched on the Internet and can not find a solution to the problem. Already restored the network connections and even restored the factory settings.
Please help me... What is the problem ?