[Captivate Android Development] Plato56:
Hello to our Captivate brothers from the Vibrant forums.

You are doing some incredible work over here with the GPS software, we dont have anyone working with the GPS software at this level and it seems you have done a fantastic job of compensating for poor signal quality. What we do have is a group of us that have a decent electronics background and have all but solved most of our issues with a simple hardware tweak. After reading this post, It occoured to me that maby your guys have the same issue as we did. Bad contact between your GPS and your antenna. I just wanted to share some of our observations with you and thought maby by combining what we've done with the software work you guys have done over here, there might be even more success in getting the SGS GPS not just working but perfected.

http://xdaforums.com/showthread.php?t=878970

A few observations as I have been one of the major contributers to this concept and the first one to actualy open my phone and try it, I've had alot of time to test some major variables .

1. For us, the key was simply improving the connection to the antenna. Once we did this, GPS locks were not difficult to come by as signal strength and satalite lock stabilty improved so much that many simply left their software stock . This basicly removed a large variable for us. On stock 2.1 software, most are still getting wandering GPS issues often, but the locks remain stable in GPS Test software.

2. We have a lot of dev who have worked with the most recent 2.2 leaks and have discovered that the 2.2 MODEMS dramaticly improve our GPS performace, even more so when coupled with recent 2.2 leaked software. For the Vibrant, 2.2 was the first time that we had GPS software that used the Jupiter.xml stuff that you guys have had all along. Im not sure any of us actualy know why the modems helped so much, but they did.

3. Googles nav software is imperfect. I have ploted the raw GPS data by hand as taken from GPS Test and have realized that the GPS is very accurate. I think your on to something with the idea that heavy process load is causing interference some how. I spent a few days not using the Navigation software just observed with Google maps this week and found the acuracy to be amazing. Tried plotting a route, and sure enough, issues. Not major, but not as accurate as just using the over head map for my location.

4. We have absolutely narrowed one source of interference for our phones. That is the WiFi radio. If we have it on at all on the more recent JLx 2.2 builds, the GPS is either literaly all over the place or wont lock at all. Turn it of, and you got dead on navigation instantly. If we turn the WiFi off and set wireless networks to on, it uses the cell towers to get a quick general location and the GPS narrows it down real quick. Im not saying this is the only source of interference, but it is the most noticeable for us. Now that im thinking about it, I wonder if the new modems didn't reduce our cellular and 3g signal strength, thus reducing its potental for interference.

These are just some of the findings that we have with our Vibrants. I don't know if any of it would be usefull to ya'll here, but I figure the more knowlage there is to draw on the more likely there will be a "Universal GPS Fix" for the SGS.

Samsung relesed some software recently that resets our GPS setting in LBS test and to factory defaults and I suspect that it also overwrites the Jupiter.xml file as well as the other GPS config stuff. By using this with the hardware fix and a good 2.2 rom some of us have gone from 5 minute lock times with garbage accuracy to 9 out of 13 birds indoors in under 15 seconds. Outside I can lock now lock to under 20ft in about 10 seconds with a hot start. Sometimes it so fast, Its hard to tell if its trying to lock, or if the sofware just has not finished loading the map. Cold starts are a bit longer but not drasticly. This is from a phone that would not lock in less than 5 minutes out of the box.

Good luck, and hope to see someone try our hardware fix on your phones. If it were to turn out that you have the same poor contact issues we do, then fixing that and using the software fixes in this thread should result in a GPS that would rival the best on the market.