Research And Implementation Of Compass Navigation Anti-jamming Algorithm

The global navigation satellite system(GNSS) can provide all-weather and all-day navigation and positioning services, and is playing a more and more important role in the field of military and civilian. But since navigation satellites are very far away the earth, and the satellite signal power stays in a very low level, the navigation system is very susceptible to interference, intentionally or unintentionally, leading to the decrease of the star-search performance or even the loss the stars. For a long time, all countries have attached great importance to the development of satellite navigation system and the research of navigation anti-jamming technology. With the gradual construction of the COMPASS satellite navigation system, the research of navigation anti-jamming technology has made significant achievements. In this context, the performance of navigation anti-jamming algorithms and implementation process have been studied in this thesis.Navigation anti-jamming algorithm based on array signal processing has been widely studied because of its good anti-jamming performance. The receiving signal models based on broadband and narrowband signal are intorduced in the thesis. The spatial and joint space-time anti-jamming methods based on array signal processing, as well as the application of power inversion adaptive algorithm are also introduced. These content lay a good foundation for the further study of anti-jamming algorithm performance.In view of the broadband signals in the COMPASS navigation system, the joint space-time processing method is introduced for two-dimensional space-time filtering process. And in the actual situation, since it is very difficult to get the direction of the satellites in real time, the blind power inversion adaptive algorithm is applied to the structure of the joint space-time processing. In order to compare the algorithm performance of conventional LMS method and subspace projection method and the improved power inversion algorithm, some simulations have been done under the condition of different number of interferences, different time tapping length and tapping interval. The influence on the improved power inversion algorithm of the interference incident angle, interference intensity and the number of snapshots has been analyzed. For the channel inconsistency of broadband multi-channel system, frequency-domain equalization algorithm and its improved algorithm are studied. And the simulation results show the equalization performance of the two algorithms.This thesis introduces how to implement the improved power inversion algorithm in current EP2S180F1020I4 & TMS320C6748 COMPASS navigation anti-jamming hardware platform. The uPP interface for FPGA and DSP data communication, the generation process of correlation matrix and weight calculation method based on the Jacobi eigen decomposition are mainly presented.Finally, after fully test of each module, the algorithm design is integrated into the existing hardware platform. And the ourdoor experiments will be carried out to verify the algorithm design, through the actual star-search results.