Filtering of the Reflected Probing PM Signals With the Rayleigh Amplitude in the Formation of High-resolution Radar Images

Abstract

The paper discusses a method of increasing the resolution of radar images (RI) in range and azimuth in the presence of a background complex in its structure, when the parameters of the reflected signals from single targets become random. The RI is formed on the basis of a side-looking radar with synthetic aperture antenna (SAR), which uses an antenna array that operates only on transmission. Binary phase-manipulation (PM) signals belonging to one cluster formed on binary linear recurrent sequences of a maximum period are used as probing signals. Radiation of the probing PM signals is carried out simultaneously in all the beams. Each beam is assigned its own PM signal from the cluster of the PM signals. A receiving device with a recurrent matched filter was synthesized to receive a cluster of the PM signals reflected from single targets of the same azimuth in all SAR beams over the range, based on the representation of binary sequences of the maximum linear recurrent period by the m-complex Markov chain with two states. The absence at the outputs of a recurrent matched filter of the side lobes of the autocorrelation function of the PM signals makes it possible to increase the noise stability of receiving the reflected PM signals by implementing a joint nonlinear filtering of discrete and continuous parameters. Computer simulation of the formation of the radar on the background of natural terrain demonstrates the possibility of obtaining the radar with high resolution range in real time.