Current position after switching on

In order to reduce power consumption I disable my phone every now and then.
When I switch back on, the map position should be the one I switched the phone off.
So it is, but after 0.5s it scrolls just somewhere in the map (maybe to the tranmitter mast' pos. of my provider?).
After having found my gps pos it switches back to the right pos. This behavior is very confusing. The pos. just should rest on the
last gps pos. until the new one has been found.

This behavior still annoys me very much. Is it not possible to disable a position-fix if it's computed via the cell-location? I only want to have a GPS fix!
Theres an option in the preferences "Accuracy for position fix". I set it to 20 meters as I hoped that a cell-fix is very inaccurate. But it doesn't help