Research And Implementation Of Digital Beamforming Algorithm For Phased Array Subarra

The digital array radar using digital beamforming technique can simultaneously form receiving digital multi-beam,perform multi-target detection,interception and tracking,and achieve adaptive interference suppression in space domain.While,the sub-array phased digital beamforming technique can effectively reduce the hardware complexity,and cost of the digital array radar system,and the interactive bandwidth of the digital signals.It is an effective tradeoff for the flexibility and complexity of the large-scale array.In this paper,researches on fast spatial-domain anti-jamming algorithm and simultaneous independent multi-beamforming algorithm are carried out for two different structures of sub-array phased digital array.In response to the requirement of spatial adaptive anti-jamming for a 320-element localized sub-array phased digital array system,the implementation schedule and transplantation of fast spatial-domain anti-jamming algorithm are carried out.The beamforming performance of the digital array system is comprehensively tested.The main contents of the paper includes:1、For the localized sub-array phased array,a fast spatial-domain anti-jamming algorithm for solving sub-array spatial ambiguity is proposed.The algorithm employs two-dimensional fast Fourier transform to estimate the fuzzy interference angle,Schmidt orthogonalization to achieve the orthogonal projection of the interference subspace,and muti-angle orthogonal projection technique to enlarge the nulling widths.The algorithm employs the sub-array dimensionality reduction structure to achieve the spatial-domain interference adaptive suppression.Under the condition that the anti-jamming performance is not significantly deteriorated compared with the full digital array,the calculation complexity of the algorithm is effectively reduced.2、For the interleaved sub-array phased array,a beamforming algorithm is proposed to simultaneously form two independent directional beams.According to the two required directions,the working frequencies are optimally selected to flexibly adjust the grating lobe positions of the sub-array patterns.By selection or suppression of different grating lobes,two independent directional beams with maximum gain can be formed at the same time.3、The implementation and verification of proposed fast spatial-domain anti-jamming algorithm is realized on TI’s 8-core DSP C6678 digital signal processor,according to the working mode and timing requirements of the 320-element 80 localized sub-array phased digital array system.The total processing time of the measured algorithm is less than 9ms.The relevant antenna function and performance testings of the system are completed in the microwave anechoic environment,including: channel calibration,transmitting and receiving beam pattern testings with G/T and Effective Isotropic Radiated Power(EIRP),etc.The testing results satisfy the requirements.