Design of high sensitivity GPS signal acquisition circuit with new frequency domain search strategy

Abstract

In this paper a GPS signal acquisition circuit is designed based on FPGA and a new GPS signal frequency domain search strategy is proposed and implemented by combining the cyclic shift sweep and DDS sweep. The system frequency domain search speed is improved evidently. And TTFF (time to first fix) can be extremely reduced, with out to much extra hardware costs. As a result, the weak signal acquisition and fast acquisition could be achieved simultaneously. Through hardware testing the sensitivity of the system and the advantages of the new strategy in the search speed is validated.