Analysis And Research Of Rapid C/A Code Acquisition Scheme Based On FPGA

The requirement to accurate navigation becomes stronger nowadays Along with society’s progress and development. Many countries compete with foundation of their own satellite navigation system. The technology of satellite navigation and positioning is important strategic resources with national security because of its application in military field. It has very good market prospect with wide application in civil field as well. As is the most mature satellite navigation and positioning system in the world more and more people start to do research on GPS receiver. And they have big concern to acquisition algorithm of GPS signal which is the key point of IF signal processing in receiver.The paper introduces the GPS and other satellite navigation and positioning system briefly initially. Then it elaborates the structure and generation method of GPS signal as the background of acquisition algorithm. The design part gives analysis to structure, performance and application scope with different acquisition algorithm firstly as a general view. The design adopts fast acquisition algorithm method of FFT PN code based on coherent and incoherent integration according to the goal and constraint. This algorithm implement search with whole Doppler frequency domain and code phase of single satellite in forty seconds theoretically. The time length could be reduced with parallel multi-channel.And then the paper deduces the impact to the performance with different parameters by verification of performance under each parameter such as setting1macro second as coherent integration time. Thus the final parameters are fixed in design with optimization. The acquisition algorithm including IF signal generation and satellite signal acquisition is verified by simulation with modeling GPS signal based on Matlab in the third chapter. the design is implemented by verilog language based on Vertex5XUPV5-LX110T design kit of Xilinx company and Modelsim simulation platform in the fourth chapter.