Sgt Fury
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- Dec 27, 2010
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There are two distinct issues regarding GPS reception. One could be the screws if they are loose. However if you just changed the ROM it is not likely the screws will correct the issue. You can try tightening the screws just in case, however you will become frustrated if this does not fix the problem. If after changing the ROM the GPS does not work it is related to the new ROM load. This does not mean there is a flaw in the new custom ROM but instead how it replaced the prior software. In my case rebooting the phone seemed to correct the problem but this may not always be the case.
Keep in mind after changing the ROM the GPS must cold restart meaning it must find satellites, sync the clock and decode the PRN information for a position solution. We all know the GPS also has an aGPS feature that supplies orbital satellite data (almanac) and ephemeris information to help the GPS receiver when the phone is inside a building or in an urban canyon area. This is fine if the aGPS function is working… however if aGPS is not working or worse the aGPS load is corrupt, outdated or from a different area the GPS will be totally confused and will not lock on a position solution. All indications point to this type of issue. If you take the phone outside in a clear sky area and use a GPS monitor you will probably see many satellites tracking within a few minutes maximum however it will not lock on any. This is very typical of corrupted or wrong aGPS data. With this is mind the very first thing to do if the screws do not fix the problem is to go outside in an open sky and monitor GPS satellites using a monitor program. If you are able to track strong GPS satellites but they will not lock into a solution it is not the screws and you should try a reboot or maybe re-flash to stock to correct the issue. There are also many other threads discussing other possible solutions to the problem.
I know it has been mentioned already here but I cannot stress enough go outside in an open area or you just end up creating more frustration. This is particularly true if you are inside a metal building with metalized glass windows next to many other metal buildings, etc. In this instance everything with your phone may be fine and it simply cannot effectively cold start due to very low GPS satellite signals, multi-path and reflected signals and other technical issues that aGPS alone cannot overcome. Remember the GPS signal is extremely weak by the time it reaches your GPS device and the signal is very complex. In this example everything may work fine once the phone is outside in an open area for a few minutes. Once it is has passed the cold start it will probably be ok after going back into the building however accuracy will be decreased while indoors.
Credit for this post goes to labtex3 on xda forums
Keep in mind after changing the ROM the GPS must cold restart meaning it must find satellites, sync the clock and decode the PRN information for a position solution. We all know the GPS also has an aGPS feature that supplies orbital satellite data (almanac) and ephemeris information to help the GPS receiver when the phone is inside a building or in an urban canyon area. This is fine if the aGPS function is working… however if aGPS is not working or worse the aGPS load is corrupt, outdated or from a different area the GPS will be totally confused and will not lock on a position solution. All indications point to this type of issue. If you take the phone outside in a clear sky area and use a GPS monitor you will probably see many satellites tracking within a few minutes maximum however it will not lock on any. This is very typical of corrupted or wrong aGPS data. With this is mind the very first thing to do if the screws do not fix the problem is to go outside in an open sky and monitor GPS satellites using a monitor program. If you are able to track strong GPS satellites but they will not lock into a solution it is not the screws and you should try a reboot or maybe re-flash to stock to correct the issue. There are also many other threads discussing other possible solutions to the problem.
I know it has been mentioned already here but I cannot stress enough go outside in an open area or you just end up creating more frustration. This is particularly true if you are inside a metal building with metalized glass windows next to many other metal buildings, etc. In this instance everything with your phone may be fine and it simply cannot effectively cold start due to very low GPS satellite signals, multi-path and reflected signals and other technical issues that aGPS alone cannot overcome. Remember the GPS signal is extremely weak by the time it reaches your GPS device and the signal is very complex. In this example everything may work fine once the phone is outside in an open area for a few minutes. Once it is has passed the cold start it will probably be ok after going back into the building however accuracy will be decreased while indoors.
Credit for this post goes to labtex3 on xda forums
