Parallel algorithms and processing architectures for space-time adaptive processing

This paper describes methodologies for the on-line calculation of the weights to be used in the linear combination of the received radar data by a set of N antennas and M pulse repetition intervals (PRIs) for the derivation of the adapted space-time filter output. The numerically robust and computationally efficient QR-decomposition is used to derive the so called MVDR (minimum variance distortionless response) and lattice algorithms. Both algorithms are represented as a systolic computational flow graph. The MVDR is able to produce more than one adapted beam focused along different DOAs and Doppler frequencies in the radar surveillance volume. The lattice algorithm offers a computational saving; in fact its computational burden is O(N²M) in lieu of O(N²M²). A comprehensive analysis of the numerical robustness of the algorithms is presented when the CORDIC-algorithm is used to compute the QR decomposition (QRD). Benchmarks on general purpose parallel computers and on a VLSI CORDIC (co-ordinate rotation digital computer) board are presented