Evaluating the deformation monitoring capability of a ground based SAR system with MIMO antenna

By increasing the applicability of ground-based SAR (GBSAR) systems in geoscience and remote sensing, the development and evaluation of new systems have gained attention. GBSAR systems can be utilized for monitoring areas that are hard to or cannot be seen by the airborne or spaceborne systems. Furthermore, they have better spatial and temporal resolutions and are cost-effective and easy to implement. This paper develops and evaluates a GBSAR system by combining a multiple-input multiple-output (MIMO) radar and mechanical linear rail as a synthetic aperture in azimuth direction (MIMO GBSAR) in a simulated environment. The considered radar sensor consists of two transmitters and four receiver antennas, operating at the W band frequency between 76-81 GHz. Azimuth compression consists of two main steps: MIMO beamforming and then compressing all gathered signals in the azimuth direction. According to the simulated results, the proposed MIMO GBSAR is able to improve the azimuth angular resolution to 4.9 mrad, compared to the 400 mrad angular resolution of the simple MIMO radar. A monostatic radar sensor requires 920 steps to complete a 0.9 m linear synthetic aperture, while the proposed MIMO GBSAR requires 115 steps, which implies a faster data acquisition rate. A simulated experiment was conducted in order to evaluate the interferometric capability of the considered sensor. The target’s displacement rate was considered 0.1 millimeters per epoch. According to the results, the errors’ amplitude was smaller than 1.5 micrometer, and the average displacement error was 0.32 micrometer.