Abstract:

Acquisition time of global position system (GPS) receiver,
which is the main factor contributes to time to first fix
(TTFF), can be shortened by estimating the Doppler frequency
shift through external inertial navigation system (INS) information
and almanac data and reducing the searching area. The traditional
fast acquisition is analyzed, the fast acquisition of the GPS receiver
aided is presented by INS information, and the signal is fine captured
by spectrum zooming. Then the algorithm is simulated by
sampled GPS intermediate frequency (IF) signal and the result
verifies that this acquisition can dramatically improve the capability
of GPS receiver and reduce its acquisition time.