[Galaxy S I9000 General] SysGhost:
I did suspect something like this.

I have to turn of my bluetooth devices and the wifi in order to get a good and fast GPS fix.

I also have to turn off nearby wireless devices. (For instance other smartphones bluetooths and wifis I got in my other pockets)

By the way, the pedestrian setting mentioned earlier did help my "floating around" problem.

I guess that when the GPS software "detects" me in vehicle mode, it lowers the update rate and tries to calculate my direction in advance. Also it causes the marker to stick itself to roads and paths. I also guess it does "detect" vehicle mode when the speed reaches a preset value. (Which it does when i'm on my bike)

That's why I need to "forcibly" set the GPS in pedestrian mode whit help of the mentioned DynMode setting.

EDIT:

The thing about the Dynamic Mode (DynMode) on automatic, is that once it enters vehicle mode, it does not revert back to any previous modes. It seems to remain in vehicle mode, even after restarting the applications. Only way to get back to "automatic mode" is to reboot the device. It does switch from pedestrian mode to vehicle mode once the speed is passed that magic preset value. But once there. it won't go back again. So much for the automatic mode. Bah!

EDIT 2:

Now I can confirm the bluetooth interference with the GPS.

I use an A2DP headset (Bluetooth hifi stereo sound) and everytime I use it, the GPS would have trouble fixing the position. I downloaded an app called "GPS Test", to see what happens.

Here's the result: (Devices wifi is off in all scenarios)

A2DP device turned off, device Bluetooth is on, but in standby:

GPS takes a few seconds to lock on, while the GPS is searching, it loses a satellite every now and then, but is able to recover it. once it finds at least 10 satellites, it locks on and a position is given. Precision is around 160 feet, and slooowly gets better, with "hickups" every now and then where the precision gets worse for a short while. After a few minutes its around 30 feet in precision. It remains there, jumping between 40 and 30 feet.

A2DP device turned off, device Bluetooth is off.

GPS takes about a second to lock on. Very fast i.m.h.o. No satellites are lost during search. and once 8 satellites are found, it locks on and a position is given. Precision is around 30 feet, and gets better after another few seconds. Then it remains stable at 16 feet precision.

A2DP device turned on, device Bluetooth is on. But everything is in standby. No playback nor other "active" bluetooth traffic

GPS takes about a minute to lock on. Sometimes up to 2-3 minutes. It loses satellites often. It seems to be stuck at 3 satelllites at first, but sloowly get 4 satellites... 5 satellites...6 ....4.... 3.... 2... 6... 7... 2... 1.... 6.... 7... 8 ... 9... 7... 9... 10 ...lock on! Took some sweet minutes or two.

Precision is around 200 feet, and slowly gets better. But the precision is very "jumpy". It seems to fluctuate between 200 feet and 50 feet.

A2DP device turned on, device Bluetooth is on. Music playback over bluetooth to the A2DP headset.

GPS seems to take forever to lock on. in some rare cases it does lock on after 5-10 minutes.

It loses satellites all the time. It finds 1 satellite, loses it, finds 1 satellite again... then 2... loses them both... finds 2 satellites... then 3.... loses them all... ant it goes on like that forever. until it "suddenly" finds 6 satellites... 7... loses 2 of them... and it sloowly works it way up to 10 satellites. Lock on.

Lock lost... it all starts over.

Lock on after it all has repeated after yet another 5-10 minutes.

Lock lost...

Not very useful this way.

EDIT 3:

Just wanted to say that this hardware fix which this thread is all about, is still an improvement. Before my device just had a hard time locking on a position, even with all the wireless turned off. And it was also much more temperature sensitive before this "fix". Sure, it's stille somewhat tempareature sensitive, as I discoreverd that low temperatures will cause the GPS to lose its signal. (In my case below 10 degree Celsius.)

I suspect the analogue circuits in/around the GPS chip itself is negatively affected by low temperatures.