Experimental results on RIAS digital beamforming radar

The RIAS, `Synthetic Antenna and Impulse Radar´, is a new concept of 4D radar, based on the use of a transmit array, simultaneously radiating a set of orthogonal waveforms, and of a reception array, delivering sampled signals to a processing equipment, dedicated to Doppler filtering, time-space beamforming, and target extraction. This principle allows the use of fixed sparsed arrays, operating at metric wavelengths, thus providing an excellent Doppler separation, through long term integration. Advantage can then also be taken from stable, irreducible RCS of targets, as well as low cost transmitting power. The authors give an overview of the experimental trials conducted between 1988 and 1991 and the demonstrating system, in order to evaluate the performance of its surveillance mode on various points of view. Among them, three aspects have been thoroughly investigated, namely: radar coverage and radiation pattern analysis, accuracy in 4D localization, and 4D discrimination between targets. They present a description of the experimental system, of the way in which it has been operated, and of the kind of data which has been recorded during test flights