Features of the trajectory signal processing in the distributed radar when rotating the joint set of transmitting and receiving antennas
Authors: Tatarsky B. G. , Arkhipov А. V. 
Published: October 2023

Increasing the resolution of ground survey radar systems (radars) makes it possible to obtain images of ground objects and the observed surface with high quality. At the same time, as it is known, the most difficult is to provide high resolution radar by angular coordinate. The method based on synthesis of artificial aperture allows to increase significantly the angular resolution of airborne radar. The capabilities of a radar station with synthesis of antenna aperture (SAR) in angular resolution are determined by the structure of the spatial and temporal trajectory signal formed in the process of synthesis. In this case, the resolution is determined by the angular size of the synthesized aperture. The purpose of this article is to consider the features of the trajectory signal structure and its processing during synthesis of an artificial antenna aperture in a distributed radar station consisting of a set of two receiving and one receiving-transmitting modules rotating in a circle. It is required to analyze the trajectory signal structure and evaluate the potentially achievable angular resolution capabilities of a distributed radar station when synthesizing an artificial antenna aperture under conditions of rotation of a spatially spaced set of phase centers of real antennas. To analyze the structure of the trajectory signal generated in a distributed radar station, we have considered the geometry of the problem, because it determines the change in the current distance between the phase center of the antennas and the observation object and is the main generating factor of the arising modulation of this signal. An informative tool for analyzing the characteristics of radar systems with synthesis of antenna aperture by potential resolution, is the analysis of the output response of the optimal trajectory signal processing system. The direct convolution method has been used to obtain the responses. Evaluation of the efficiency of coherent processing of the trajectory signals formed at the separated reception points has been carried out by computer simulation. From the simulation results presented in the figures in the article, it can be seen that the coherent processing of the trajectory signal formed at the separated receiving points during rotation of the phase center of real antennas, allows to increase the azimuth resolution of the radar. Thus, the results presented in the article show that rotation of the separated phase centers of the antennas of the receiving and receiving and transmitting modules within a range of up to 120 degrees provides the formation of a synthesized aperture when processing the trajectory signal from the observed target at each receiving point. The best azimuth resolution is obtained by processing the trajectory signal at the location of the transceiver module antenna. When coherent processing of trajectory signals formed at separated receiving points is performed together, the azimuth resolution of the radar station increases by about two times compared to the case of their separate handling.