Development and Evaluation of GPS L2C Software Receiver Baseband Signal Processing Module

GPS L2 civil (L2C) signal adopts time-division multiplexed CM and CL code for spread spectrum modulation, which makes the design of replica code one of the crucial factors that determine the implementation complexity and system performance in GPS L2C baseband signal processing. Firstly, this paper introduces several commonly used replica codes in the acquisition of L2C CM code. Through theoretical analysis, the performances of these methods are compared from the perspectives of sensitivity and complexity. Furthermore, simple CM and CL tracking methods are compared based on discriminator performances. Then, a GPS L2C software baseband signal processing module with multiple optional replica code shapes which can be implemented for acquisition and tracking schemes as required is developed in this paper. The module is utilized to evaluate the impact of the above replica code designs on acquisition and tracking performance in real-world experiments. The research results provide a test and evaluation platform for users to optimize the design of L2C receiver according to their requirements of complexity and signal processing performance.