Permanent target for synthetic aperture radar image resolution assessment

The assessment of Synthetic Aperture Radar (SAR) image resolution is essential to characterize and improve sensor performance, and to make better application of the acquired SAR data. Trihedral corner reflectors and active transponders have been widely used as standard point targets for SAR image spatial resolution assessment. However, these point targets have limitations in straight-forward result reveal and tolerance in deployment and processing errors. In light of the bar-pattern target which widely used for optical image resolution assessment, and to assess the image resolution of the SAR sensors operating at different frequency, different platform (airborne and spaceborne), a permanent bar-pattern target was designed and realized by black gravel and greyish white concrete bars. Gravel size, bar direction and width were carefully calculated according to the requirement of long-term operation. The effectiveness of the target was preliminarily validated by C-band airborne SAR, X-band spaceborne SAR data and optical image, and the result shows that the target is suitable for the spatial resolution assessment of both high-resolution SAR and optical sensors.