Implementation For Digital Signal Of GPS/BD Satellite Signal Simulator

Beidou system is a regional navigation system, which has China’s independent intellectual property rights and can provide satellite navigation positioning information all weather and all day. Beidou system has rapid positioning, short communications and precision time service three big main functions. High performance receiver development process needs in certain situations on the base part of the algorithm are verified, thus ensuring the receiver performance consistent with the expected requirements. Therefore, we must develop a source to the receiver to provide special signal, especially for the compass navigation satellite system receiver provides a signal source.In this thesis, the GPS/BD dual-mode satellite signal simulator is used as a reference and respectively by GPS system in L1frequency point and BD system in B1frequency point satellite signal simulator as an example, analyse structure and characteristics of BD system and GPS system. A detailed analysis of the satellite navigation system positioning principle, on the direct sequence spread spectrum theory is studied, on the C/A code of GPS system L1frequency and ranging code of BD-2generation B1frequency I branch generation are analyzed, study the complex dynamics of satellite signal modeling technology, discusses the whole structure design and the realization method of satellite signal simulator, realize the main control machine, communication protocol of ARM and the part of FPGA. At last, the satellite signal simulator is proved to meet the design requirements.Traditional1-band satellite signal simulator can only output rf signal, it is reasonable for most development, but in some special application scenario, the user does not need to get original rf signal, and only need to use intermediate frequency signal and data processing and analysis of the baseband signal, which verifies the correctness of baseband calculating model and effectiveness, etc. Therefore, this project developed by GPS/BD satellite signal simulator, can according to the needs of different users, choose different channel output corresponding simulation data source, the user can do it in the if signal and baseband signal output, either to meet the needs of different applications.