Realization of baseband signal processing for Beidou/GPS multi-mode receiver by FPGA

Beidou and GPS are an important part of the GNSS (Global Navigation Satellite System). Beidou is a global satellite navigation system that is independent development and operation in China. GPS is the most mature development system in the world currently. The research on the Beidou/GPS multi-mode receiver has an important practical significance at present. Compared with hardware receiver, software receiver realizes the performance of the receiver by software, and is suitable for developing new algorithms. Therefore it has advantages of flexibility, convenience, and low costs. A method to realize the baseband signal processing of the Beidou/GPS multi-mode receiver is introduced in this paper by using the chip EP2S90F1020I4, which is Stratix II series of Altera's FPGA. Using Verilog HDL to design the baseband processing module of Beidou/GPS, including the fast acquisition module and tracking channel processing module, and the tracking channel processing module includes the carrier/code NCO generation module, the complex phase rotation DDC (Digital Down Converter) module, the Beidou/GPS pseudo-random code generator, code correlator module and frame synchronization module, etc. Test results show that the baseband signal processing module based on FPGA with the DSP calculation module can achieve the normal PVT calculation.