Research And Development Of Passive Positioning Receiver

The Double Star Active Positioning System is the first generation satellite navigation system of China. It has the function of telecommunication which doesn't exist in GPS, but it has the shortcoming that supporting users are limited and are easy to expose simultaneously. The second generation satellite navigation system of China is passive, and is enormously changing the Double Star Active Positioning System and is of great military value. This dissertation conducts an investigation in the design of passive receiver.Firstly, the dissertation elaborates the development of the worldwide satellite navigation as well as present situation of satellite navigation in China. At the same time the insufficiency of the Double Star Active Positioning System is pointed out. So the research on the receiver of the passive navigational system is indispensable. After that, the dissertation introduces the navigation satellite signal system, telegraphese format, different ways of measuring pseudo-range and speed. Then, the dissertation analyses the error of the receiver from several aspects. The work is the foundation of designing the whole receiver.Secondly, the system's main framework is introduced, and the circuit of the DSP hardware is explained mainly. External memory interface, UART, clock circuit and hardware debugging are detailedly explained. Next the dissertation puts forward software function chart and software flow chart. System initialization, interrupt realization, and programmed load are designed.Finally, the dissertation concentrates on the researches of the position & speed measuring algorithm. The algorithms that include computing of the position & speed of satellites, the error corrections, pseudo range single positioning, coordinate system conversion, and single speed measuring, are designed. Some kinds of error corrections for pseudo range are given in the dissertation, i.e. satellite clock correction, relativity effect, earth rotating correction, ionospheric refraction delay, tropospheric refraction delay. Orthogonal decomposition provides an approach to solving the pseudo range observation equations without forming normal equations. Last, the position & speed measuring algorithm is simulated and real time tested, and preferable results are obtained.