Research On Anti-interference Algorithm Of Loran-C Received Signal

Nowadays satellite-based navigation system dominated in the field of navigation, Loran-C system with its signal power, anti-interference ability and other advantages still exist, it is used as a satellite-based navigation system backup means to make up for its shortcomings. In the paper, how to obtain the relatively pure Loran-C signal from the actual received Loran-C signal has always been the focus of the study of experts and scholars. In this paper, we focused on the narrowband interference suppression algorithm in Loran-C signal and verified the suppression effect by identifying the capture.The paper firstly analyzed the Loran-C navigation system and cut the single frequency interference suppression algorithm by receiving the front-end filter; then it was discussed that the classical adaptive filtering single frequency interference suppression algorithm, as the expectation signal in the adaptive filtering algorithm is more difficult to be generated in the practical application, the paper introduced the spread spectrum communication anti-narrowband interference technology and used a frequency domain filtering algorithm for suppressing single frequency interference and it was compared with adaptive filtering algorithm by Matlab simulation, it was proved that the frequency domain filtering algorithm is feasible to suppress the single interference and it is easier to implement than the adaptive filtering algorithm under the premise of satisfying the design requirement; finally, the paper analyzed the traditional capture algorithm and the delay of a GRI capture algorithm and on the basis of the latter to improve the capture algorithm, the use of phase coding characteristics, the signal delay of four pulse correlation to achieved the Loran-C signal capture. Compared with the traditional method,this algorithm in the hardware implementation of less resources.In this paper, the two anti-interference algorithms mentioned above and two kinds of delay acquisition algorithms were simulation by Matlab and the band-pass filter algorithm, the adaptive filtering algorithm and the delayed four-pulse capture algorithm were performed by the ISE simulation. Through the analysis of the above principles and the simulation results of the comparison, the design fully proved was correct and effective and well met the design requirements of modern Loran-C digital receivers.