Accession Number : ADA303493

Title :   Estimation of Target Angular Position Under Mainbeam Jamming Conditions,

Corporate Author : DEFENCE RESEARCH ESTABLISHMENT OTTAWA (ONTARIO)

Personal Author(s) : Toulgoat, Mylene ; Turner, Ross M.

PDF Url : ADA303493

Report Date : DEC 1995

Pagination or Media Count : 61

Abstract : A phased array multifunction radar (MFR) with an agile pencil beam will invariably employ a monopulse system for precise angle measurement. Such a monopulse system has three receiver channels, one channel for each of the sum, azimuth and elevation difference beamformers. This report considers a modest expansion of the number of receiving channels from three to five channels. The five channels comprise the sum channel beamformer and each half of the two difference beamformers. These five channels form an adaptive array which can be used to provide mainbeam nulling of jammers. A new algorithmic approach to mainbeam jammer nulling and target angle estimation is applied to this five element adaptive array. With this algorithm, the jammer subspace is first evaluated by sampling at ranges where the target is absent (e.g. beyond the maximum range of targets or during a quiet period when the radar is not transmitting). Data vectors are then processed to remove the jammer thus allowing the target to be detected. Finally a high resolution technique, Multiple Signal Classification (MUSIC), is used to estimate the target Direction Of Arrival (DOA) from the processed data vectors. The model used in the MUSIC technique takes into account the fact that the jammer has been cancelled in the target data vector. The performance of this algorithm is evaluated through simulations and compared with the Corrected Adaptive Monopulse (CAM) for a typical X band phased array. The new algorithm provides more accurate estimates than CAM when the target is close to the jammer, at the expense of a large computational load.

Descriptors :   *RADAR ANTIJAMMING, *MONOPULSE RADAR, ALGORITHMS, SIGNAL PROCESSING, CANADA, HIGH RESOLUTION, BEAM FORMING, ADAPTIVE SYSTEMS, RADAR RECEIVERS, NULLS(AMPLITUDE), ARRIVAL, X BAND, PHASED ARRAYS, PENCIL BEAMS, TARGET ANGLE.

Subject Categories : Radar Countermeasures

Distribution Statement : APPROVED FOR PUBLIC RELEASE