GPS-based Technology Research With Deep Combination System Inertia Assistance

In recent years, with the rapid development of the defense industry of electronic information technology, the technology of navigation, as a multidisciplinary technology, its status in the military and civilian areas is being improved; the technology of precision guidance is also becoming a key element of modern warfare. However, the traditional technology of navigation has been unable to meet the high-precision and high-performance requirements of guidance under the complex environments. The deep integrated navigation system, in which the inertial information is used to aid the navigation of satellite, can improve the acquisition and tracking performance of the satellite navigation receiver effectively; optimize the entire system accordingly, provide the reliable and accurate navigation information under the high dynamic environment, gradually becoming a hot topic in the field of navigation.With the background of "a type of rocket project", this paper mainly research the GPS signal acquisition and tracking algorithms with the assisted of inertial information, design the loop structure, complete the analysis of the experiments and verify the effectiveness of the algorithm. This algorithm is designed to further improve the dynamic performance of the receiver and lay the foundation for the study of deep integrated navigation system.In the first place, it researches the baseband digital signal processing modules of GPS receiver and the principles of acquisition and tracking, designing the basic structure of the inertial aided GPS loop and providing design scheme the entire system baesd on the analysis of GPS/INS integrated navigation technology. Then it carries out a design of inertial aided acquisition algorithm, which can accelerate the speed of capture by predicting the visible satellites, estimating doppler frequency shift and the reacquisition of the GPS signal which is out of lock. After the successful acquisition of satellite signal, the next stage will be the tracking of it. This paper is still using the more common form of the third-order phase-locked loop assisted by the second-order frequency-locked loop, besides, join the inertial information into it and create a new loop model. The analysis of simulation verify the the optimization results of it. Finally, a semi-physical simulation system is build to verify effects on the platform of DSP+FPGA.The results of simulation and experiments show that the acquisition and tracking algorithms with the assisted of inertial information, can effectively accelerate the speed of capture and tracking loop response, reducing the loop bandwidth as well. In the hot start mode, the acquisition of a single satellite just needs1second, and shorten the time to first fix. It can greatly reduce the probability of lockless, and finish the reacquisition within1～2seconds under the high dynamic environment. The performance of the entire receiver will be upgraded.