A novel fine code phase determination approach for a bandwidth limited snapshot GPS receiver

A novel fine code phase determination approach is proposed based on the deduced autocorrelation formula of C/A code for bandlimited receivers. The approach is able to significantly improve the navigation fix accuracy for bandlimited snapshot GPS receivers. A simplified algorithm based on the Taylor expansion of the correlation formula is proposed as well to reduce the computational complexity. In addition, a modified circular correlation combined with frequency FFT acquisition engine optimized for snapshot receivers is proposed, which is suitable for the proposed fine code determination algorithm. It also utilizes a proposed “coarse capture & confirm” mechanism to suppress the correlation peak distortion as well as the false alarm probability. Simulations with data sampled from both simulator and real world show that the proposed approaches are able to significantly improve the positioning accuracy in complex environments such as urban canyons and indoors.