Effects of and Compensation for Translational Position Error in Microwave Synthetic Aperture Radar Imaging Systems

Translational position error in microwave and millimeter-wave synthetic aperture radar (SAR) imaging systems can cause significant image quality degradation, particularly in nondestructive testing and evaluation (NDT&E) applications where the distance to the imaging object is relatively short. In this paper, this translational position error problem is fully studied through electromagnetic simulation. The results show that among possible geometrical causes of error, a translational position error, in the height direction, is the dominant factor in image quality degradation. Subsequently, a corresponding height position error compensation method is proposed and analyzed. The extensive simulations and measurement are performed in the X-band (8.2-12.4 GHz) frequency range. Then, by defining several evaluation metrics, the relationship between image quality and height position error is discussed quantitatively. The measured results show good agreement with the simulated results, which validates the effectiveness of the proposed analysis approach and the compensation method. The methodology proposed in this paper can be used to evaluate the feasibility or help define the required specifications of a microwave SAR imaging system for a specific application.