I bought BT920 about 2 months ago and it was installed by professional, I am having same problem with my GPS, NOT ACCURATE at all,it is behind about 200-300ft, I have Garmin in my other car and there is no comparison, "God Bless Garmin", this is joke man, I paid over $700.00 for BT920 and $120.00 for Garmin, If you guys have any idea how to calibrate this unit please post it, is anybody knows how often BT920 is getting updated signal from satellite for coordination, I think it's not updating as fast as it needs to.
Thanks