The Research Of Radar Multipath Signal Separdtion Technology

AS the rapid development of aerospace technology and the change of form of warfare in recentyears, electronic warfare and information warfare has become the main form of warfare, so which can ornot precise and timely grasp each other’s information relates to the success or failure of the war. As a kindof the radar system of the main equipment to access to information during modern warfare, how to improvetheir performance and further improve its measurement accuracy is one of the hotspots of the research ofthe filed of modern military science and technology.While the radar is measuring the low-flying target, due to the reflex action of the ground and seasurface, the electromagnetic waves of the target reflection will not only arrive radar receiver by the form ofdirect wave, also will arrive in the form of reflection echoes, so the radar receives the signal which is fromdifferent paths, namely the radar’s multi-path effects. These signals enter the receiving system by the wayof vector superposition, result the change of the signal amplitude and phase, and make the low-angle radarparameters have measurement error, namely multipath error, and finally decline in the low-angle radarmeasurement accuracy, even missing the target, as it will make the combat miss the good opportunitiesbecause of unable to accurately track the enemy targets. Therefore, how to suppress the multipath effectsand reduce the error of the multi-path effects, thus improve the measurement tracking accuracy oflow-angle radar, and which has great practical significance in the military.This article is mainly to study the question: how to suppress the multipath effect, eliminate theerrors of multipath effect, and improve the accuracy of radar measurements. In the article the producemechanism and meaning of multi-path effects is elaborated and summarized, summing up the researchprofile of the domestic and international expert on low-angle radar multipath effects question; andaccording to the radar measuring principle to establish the multi-path effects error model of a low-angleradar measurement parameters (mainly the pitch angle, distance, azimuth); by characteristics analysis whenlow-angle radar measuring and tracking the target, blind signal processing model in line with the low-angleradar measuring and tracking the target is established; on this basis, according to the proportionalrelationship between the blind source separation with the radar signal-to-noise ratio, the SNR objective function based on the maximum signal to noise ratio is establishment. By solving the objective function,the blind source single separation problem is transformed to solve the matrix problem. Signal separationmatrix can be obtained by solving the feature vector, then to obtain the best estimate of the source signal,also it means that the direct wave measurement data which is received by the radar receiver is obtained; lastusing MATLAB language simulates separation efficiency, in order to verify the algorithm effectiveness. Inorder to verify the practical application effect of the proposed method, the method is conducted field testingby using of the Dalian naval radar system. The measurement parameters data is obtained by using this radarsystem to measure the low angle of flight objective, then the algorithm is applied to process the actualmeasurement data, while taking advantage of the blind separation algorithm based on the globally optimalprocesses data, finally it is proved that blind source separation algorithm based on maximum SNR ratio issuperior to the blind separation algorithm based on the global optimum. The experimental results show thatthe error corresponding reduction of data which is processed by this signal separation algorithm, and toachieve the purpose of inhibiting the multipath effects errors and improving the low-angle radarmeasurements accuracy, then verify the practicality of the algorithm.