Design Of GPS L2 Signal USB IF Data Acquisition Experimental Platform

With GPS application fields ceaselessness goes deep into and expanded,Demand of civil customers to GPS system is getting higher and higher. Legacy GPS systems has revealed out a few shortcomings and deficiency in the process of usage. USA Ministry of National Defence has suggested GPS Modernization for making GPS system adapt to nowadays development of society needs.A remarkable improvement is to add Civilian code to L2 wave band after the GPS Modernization. To satisfy the improvement, this paper designs a kind of GPS L2 signal intermediate frequency data acquisition experimental platform. The paper detailed describes the platform from antenna part, RF front-end and data acquisition part. The antenna part choices spiral antenna which works on axis mode, RF part uses traditional GPS L1 Receiver RF components design L2 RF module, RF signal down-converted to digital IF through four stage frequency converters. The acquisition part adopts USB2.0 port, Digital IF data will be transmited to PC with this port.The paper analyses GPS Modernization and its influence, the structure of the new L2C signal and GPS receiver RF front-end design requirements, designs RF front-end design plan based on GP2015 chip. The paper researches the princples of data acquisition interface and USB port circuit, develops USB firmware program, Windows driver program and PC application program. At last we test the acquisition function by use of C/A code produced by FPGA.