ADVANCED GRAM-SCHMIDT METHOD FOR RADAR SIGNAL PROCESSING

Abstract

Context. When protecting radar stations from active noise interference acting along the side lobes of the antenna directional pattern, spatial filtering of signals is used, which is realized by using antennas that are spaced apart in space. In this case, the difference in the directions of reception of the useful signal and the interference makes it possible to form the optimal value of the weighting coefficients of the adaptive spatial filters to suppress the interference. However, if the interfering source moves into the main beam region, then the spatial differences between the wanted signal and the interference are reduced. This leads to significant distortion of the main antenna radiation pattern. As a result, the accuracy of measuring the angular coordinates deteriorates, as well as the sensitivity of the radar receiver. The article proposes a structural-parametric method for adapting a spatial filter, which ensures effective operation of the radar when exposed to the active noise interference both from the direction of the side lobes and from the direction of the main beam.
 Goal. Improving the efficiency of the radar when the active noise interference source is shifted from the direction to the side lobes to the direction of the main beam.
 Method. The proposed method makes it possible, due to the structural adaptation of the multichannel spatial filter, to exclude the distortion of the main beam of the radiation pattern of the radar antenna and to ensure its operation under conditions of possible interference from the main beam. Structural adaptation of the spatial filter is realized by the current analysis of the weighting coefficients of the compensation blocks.
 Results. The structural diagram of the multichannel spatial filter by the Gram-Schmidt method with structural-parametric adaptation, as well as the structural diagram of the compensation block, has been improved. As a result of the simulation, the possibility of eliminating distortions of the radiation pattern of the main antenna of the radar in conditions of the possible impact of the active noise interference along the main beam of the radiation pattern of the radar has been confirmed.
 Conclusions. The scientific novelty of the work consists in the improvement of the signal-processing algorithm at spatial filtering both when exposed to the active noise interference from the direction of the side lobes, and when the interference source is shifted to the direction of the main beam of radar. The practical novelty of the work lies in the development of a structural diagram and a mathematical model of an improved spatial filter with structural-parametric adaptation.