SIM808 with UFL antenna system works outdoors, does not work on vehicle dashboard...gain problem?

Hi all
I have been following your post. Even I have made a battery operated device having passive antenna system with a UFL antenna. It takes too long to fix GPS. In moving vehicle it’s not fixing at all.
Let me know if 2.8V with 10ohms and series 47nH inductor will be sufficient to improve reception. Or do I need higher voltage of 3.3V ??
Kindly let me know. Does it actually improves fix within seconds ? My code has cold reset of GPS at very beginning.