Design And Implementation Of Space-Time Anti-Jamming Algorithm For Navigation Receiver

GNSS(Navigation Satellite System Global), is a satellite navigation and positioning system with the development of modern science and technology. The receiver on the ground receive satellite signals to achieve positioning solution, timing and other functions. GNSS has played a huge role in the fields such as military, agriculture, mapping, meteorology and so on. At present, all countries in the world regard it as a key development area, and it will have a great influence on the national economy and the people's livelihood. With the increasing complexity of the spatial spectrum, the research on the anti interference of the navigation receiver has gradually become the focus of scientific research.The main work of this paper is as follows:1, in this paper, take the GPS system as an example, according to the characteristics of the GPS system and the form of interference, the signal model is established, and the mechanism and the influence range of the jamming is analyzed.2, in this paper, focuse on the antenna array with patial adaptive and space time adaptive filter, and establish the model by Matlab, analyzes the advantages and disadvantages of different arrays based on linearly constrained minimum variance, and combined with the size, spacing, mutual lotus and other problems in practical engineering, select uniform circular array as antenna array form; according to the theoretical deduction and simulation results, spatial algorithm can simply distinguish the interference signals and suppress it, if the navigation signal from the same direction, inhibited effect is poor, because has a higher degree of freedom, the space-time adaptive anti jamming effect than the spatially adaptive; Then, the influence of the matrix element and the number of delay taps is analyzed in the space time anti jamming, and the most appropriate array element and the number of taps are deduced by simulation; studied the space-time dimensionality reduction algorithm to improve the efficiency of the algorithm, compared to the stlms and multistage Wiener filtering algorithm on the anti-jamming performance difference,analysis results show that although the stlms computational complexity to less than multistage Wiener filter, but the number of snapshots were significantly greater than those of the former.3, based on the FPGA+DSP hardware platform for the implementation of the project, the XC7K325 T that can be programmed complete the processing of the data acquisition, the down frequency conversion, the space time adaptive filtering and other processing procedures, the coefficient of the filter is calculated by TMS320C6678.4, the test environment is set up to test the system. the system uses narrow band interference, broadband interference, broadband frequency sweep jamming, etc. to make a comprehensive test of the different forms of interference, such as the number of interference, the combination of multiple kinds of interference and the different direction of the interference. The test results show that the design parameters can meet the design requirements.