Research On GPS Signal Simulation Technology And Software Receiver

Global position system is new generation of satellite navigation system all over the world and wide-used in military and civil areas, such as vehicle navigation, geographical measurement, and orbit orientation of aircrafts and so on.Along with the modernization of china, industry and military field have high technical requirement for navigation performance which can not be met by present hardware receiver. Software receiver is facilitated to develop the location precision and compatibility because of modularization on digital signal process and flexibility. GPS signal, moreover, is resource to validate the performance of software receiver. Researchers need spend more time and resource on simulation in hardware method because of the influence of RF signal transferring, transferring delay and multi-path interference; however it can take advantage of high efficiency and lower cost to simulate the signal in software method. Real signal acquisition is another method to acquire GPS signal for the research on real-time software receiver in the future.The work of this thesis was as below:1. Analyzed GPS signal downlink in detail to prove that it has feasibility to simulate the change of real GPS signal in the transmission via carrier-noise-rate or signal-noise-rate, and presented the method to generate GPS IF digital signal for simulation of GPS signal based on multi-satellites with adjustable carrier-to-noise ratio and Doppler.2. Designed software receiver based on the analysis of GP2021 internal framework and presented the structure of build-in finite status machine. Baseband signal process could be completed accurately, including signal acquisition, tracking and navigation data demodulation.3. Presented a method to acquire real GPS signal and designed GPS signal acquisition system including the antenna, RF front-end, serial-to-parallel module and data acquisition card. The storage format of GPS signal is compatible with the software receiver above. The design on the method to generate GPS simulated signal and software receiver can be used for reference. But signal acquisition provides real data source for the research and make of real software receiver in the future.