A relaxation direction finding algorithm for large dynamic incoherent signals based on chaos optimization

Aiming at the problems of large calculation amount and low direction finding accuracy of non-equal power navigation interference signal caused by the refraction effect of radio wave propagation along low altitude link and the difference between receiver and interference distance, an improved relaxation algorithm based on chaos optimization is proposed. The algorithm takes advantage of the ergodic, non-repeatability and unpredictability of chaotic phenomena, and introduces chaotic state into the optimization variables. After obtaining an approximate optimal solution, the algorithm makes use of the sensitive dependence of chaotic variables on initial conditions to conduct a fine search in the adjacent region of the optimal solution, thus greatly improving the search speed and realizing the direction finding of non-equal power navigation interference signals. When the algorithm is applied to the simulation of uniform linear array, it can reduce the computational load and improve the accuracy of the direction finding algorithm when two or more strong navigation interference signals coexist with weak target signals. Under the condition that the signal to noise ratio of the weak signal is higher than 15 dB and the interference to signal ratio of the strong interference to the weak signal is lower than 25 dB, the root mean square of the direction finding algorithm proposed in this paper is less than 3°. Compared with the algorithm with the highest simulation accuracy in the paper, the accuracy is improved by about 0.1-0.2°.