Radiometric Resolution Measurement for TerraSAR-X Sensor by Realizing Man-Made Homogeneous Regions

A homogeneous region exhibiting a stable and high backscattering coefficient is crucial for the radiometric calibration and performance evaluation of synthetic aperture radar (SAR) systems. However, creating such a region in practice presents significant challenges. This study presents a new method for creating a uniform region with consistent backscattering, defined by a known backscattering coefficient, using specially designed metal grids. This method is applied to evaluate the radiometric resolution of the TerraSAR-X sensor.The proposed man-made grid-structured target, referred to as the metal grid, is constructed from aluminum. The backscattering coefficients of this grid were measured across various incident angles and frequencies in a microwave anechoic chamber. Radar cross-section (RCS) measurements confirm the target's strong backscattering properties. Using this designed target, homogeneous regions with high backscattering were created at Shanghai Jiao Tong University, China. Two spaceborne experiments conducted by the TerraSAR-X satellite over the test area were carried out to assess the radiometric resolution of the SAR sensor. The experimental results demonstrate that the radiometric resolution values derived from the TerraSAR-X images closely align with the reference values provided in the product specifications. Additionally, the developed strong backscattering homogeneous region proves to be highly effective and well-suited for SAR radiometric calibration and other related applications.