Research On Angle Estimation By Adaptive Sum And Difference Beamforming With Phased Array

When jamming occurs, the adaptive signal processing distorts the sum anddifference patterns, resulting difference between the adaptive monopulse ratio curve andthe common monopulse ratio curve, causing angle estimation performance degradationor even failure. When the signal power and interference power approach, it will appearsignal cancellation which leads to a serious decline in output performance withoutprocessing. To deal with the above problems, robust adaptive sum and differencebeamforming without correction for angle estimation is studied. The proposedalgorithms, which are not sensitive to interference power, have robust interferencesuppression and acceptable performance of angle estimation. In the presence of sidelobejamming, based on the structure of three channels generalized sidelobe canceller inphased array, the eigenvalue decomposition and subspace tracking method for theconstruction of robust reduced-dimension blocking matrix are proposed. Compared withthe other algorithms, the proposed methods with less impact to monopulse ratio do notneed correction. In the presence of mainlobe jamming, according to the fractaldimension of the rectangle array, the received data is processed in azimuth and inelevation respectively. According to the process above, monopulse ratio can bemaintained in one dimension and the mainlobe jamming can be suppressedsimultaneously in another dimension. The processing results of simulation andmeasured data show the effectiveness and advantages of the proposed algorithms.