Research On GPS Anti-jamming Method Based On Space Domain

Due to low level of signals from GPS(Global positioning system)satellites,GPS receivers are vulnerable to the interferences and could not function well for achieving required navigation and positioning.Therefore,anti-jamming is of primary importance for solving the problems.Some models are established for received signals with different formations,dealing with the analysis for anti-jamming technology,interference forms,and anti-jamming principle with adaptive nulling antennas.Simulation results for these models from different formations are given.four kinds of adaptive algorithms are compared.The simulation results show clearly the advantages and disadvantages of the LCMV algorithm based on LCMV criterion and the LMS algorithm based on MMSE criterion.In the uniform linear array,the LCMV algorithm is simulated under different interference sources and different jamming-to-noise ratios.Based on the simulated results above,an LCMV algorithm combined with phase compensation is proposed for further improving the algorithm.For the uniform linear array,simulations are carried out in the environment with different interference sources and different jamming-tonoise ratios,and comparisons are also made with the simulation results of the LCMV algorithm.Results show that compared with the original LCMV algorithm,the LCMV algorithm combined with phase compensation reaches an improvement in null depth from4 dB to 8dB in the direction of the interference signal under different interference sources,thus improving the signal-to-noise ratios from 5dB to 7dB for GPS signals and reducing the error rate of the received signals.Under different jamming-to-noise ratios,compared with the original LCMV algorithm,the proposed modified LCMV algorithm has an improvement from3 dB to 6dB for the null depth in the direction of the interference signal.The algorithm also has better anti-jamming performances.