Implementation of Parallel Digital Correlator Based on FPGA

Spreading codes correlation is one of the key technologies for spread spectrum receiver.This paper mainly describes the application of digital correlator in GPS signal acquisition and implementation in FPGA.The parallel calculation method is adopted in the design,thus to reduce calculation time.First,the calculation process of GPS signal acquisition is illustrated,then,the circuit structure of digital down convertion is given and the frequency precision of carrier NCO analyzed,then the spreading code correlation circuit is designed,finally a satisfactory acquisition performance is obtained by simulation and test on the design with ModelSim software and Xilinx Virtex-5 LX220 FPGA.