Problems with latest version

[nachum]

Hello.  I downloaded the most updated version (v.10.0.0. GP) into my phone, but I have several problems.
The main problem is recording track while riding a bike does not follow the real track, it creates straight lines instead. I tried to modify some configuration parameters (GPS, Application, tracks/routes and more) but it hasn't changed. (The application is NOT in save battery mode of the Android)
Can you recommend what are the right values for the main configuration parameters?
In addition, if I close and reopen screen (to save battery), my location on the map is lost.
Also, under "setting->Sensor" there is "Main device position". What is it?
Thanks for your help!