Enhancing Efficiency of Space-Time Processing of Radar Signals under Exposure of Combined Interferences

Abstract

The noise immunity of radars is essentially reduced under the simultaneous exposure to active noise and passive interferences. This is stipulated by the passive interference decorrelating the active noise and also by the disruption of interperiod correlation of passive interference during the adaptation of weight coefficients of spatial filter. This paper proposes and investigates a new method of forming the classified training sample (CTS) based on the interchannel correlation analysis of range signal. This method makes it possible (in the current sounding period in terms of the maximum magnitude of interchannel correlation coefficient) to determine the range interval, within which the passive interference has the minimum level, and to form the optimal value of weight coefficient of spatial filter for its use in the next sounding period. In addition, the method allows us to form an optimal weight coefficient for compensation of active noise interference in all sounding periods of the next frequency burst during the burst-mode signal processing in the last sounding period of the current burst. The simulation process has revealed that in this case the modulation of passive interference present in compensation channel is also eliminated. It can essentially enhance the efficiency of extraction of useful signals against the background of passive interferences during the time (frequency) processing at the second stage of space-time signal filtering in radars. It has been established that the use of CTS makes it possible to significantly reduce the duration of transient during the adaptation of weight coefficients of spatial filter that enables us to enhance the efficiency of active noise suppression under the simultaneous exposure to nonstationary passive interferences.