Satellite Navigation System Interference Suppression Technology

Satellite navigation system is regarded as a great revolution to the navigation technology. While its rapid development in various field, the problem of its prone to be interfered by radio interference get much attention. When the processing gain do not provide sufficient improvement, it is necessary to employing various anti-jam measures, especially in strong jamming environment. Satellite navigation system's ability of anti-jam in jamming environment is the key problem to its further development. Therefore , it is very important and urgent in both theretical researches and practical applications to propose various effective measures in order to enhance the system's perfermance.This dissertation focuses on two aspect: the first is anti-jam technology of multi-antennasignal processing ;the other is signal acquisition in jamming environment. The main efforts ofresearch consist of four issues:Chapter â…¡ studies multipath rejection problem. Firstly ,the effects of short-delay multipath to the DLL,PLL,and SNR of receive signal are discussed. Then the effects of multipath to multiple closely spaced antennas are presented. And solve the problem by promote a new method based on Extended Kalman Filtering, which utilize the correlation of measure data of DLL,PLL and SNR of each antenna.Chapter â…¢ studies attitude determination problem by multi-antenna. The coordinate system and ad-algorithm is introduced firstly. Secondly, the algorithm and ad-receiver figure are put forward, which can work well in jamming environment for attitude determination while track the satellite's code phase and Doppler frequency. An ad-algorithm based on SNR is promoted which use few antenna, the method can be used as a complementarity of other ad-system .Chapter â…£ studies anti-jam technology of adaptive array. The optimization weight and performance of adaptive array is discussed. Then, based on the characteristic of navigation signal, the figure and algorithm of adaptive array are improve on, which has a superior performance on CR and a little inferior on SINR compared with optimization weight adaptive array.Chapter â…¤ studies the detection and acqusition of satellite navigation signal. The detection perfermance of envelope detector and square-law detector is analyzed, and acquisition performance of non-correlate detector is studied later. The result is important to analysis direct long-cycle PN code acquistion .