A refined geometric correction algorithm for spotlight and sliding spotlight spaceborne SAR

In this paper, a novel algorithm of geometric correction for spotlight and sliding spotlight SAR is presented. Synthetic Aperture Radar (SAR), which is independently of weather and light conditions, is a well-established imaging technique for remote sensing [1]. With the increasing demands for higher resolution, spotlight and sliding spotlight modes have been presented. The key requirement for understanding SAR image is to map the location of pixels accurately, and this requires a more accurate geometric correction algorithm to assure the quality of spotlight and sliding spotlight SAR image products [2]. In 1982, a Range-Doppler location method, which is effective for stripmap SAR, has been presented by John C. Curlander [3], but it's not effective for spotlight and sliding spotlight SAR. Considering the imaging process model [4], the space-time mapping relationship and the space-frequency mapping relationship, we have modified the location equations to improve the geometric correction for spotlight and sliding spotlight SAR. The simulation result shows the validity of the algorithm.

1. INTRODUCTION

Synthetic Aperture Radar, which is independently of weather and light conditions, is a well-established imaging technique for remote sensing [1]. As standard all-weather observation tools, SAR systems play important roles in environment monitoring geological investigation, ocean monitoring, ground moving target indication, and resource investigation. Effective application of SAR requires accurate location of each image pixel. Historically, location of spaceborne SAR imagery has relied on the use of tie points to determine the absolute location of the image. The location of each image pixel is then determined relative to these tie points. [3] In 1982, John C. Curlander presented a Range-Doppler location method, to derive the absolute location of an arbitrary pixel independent of any reference or tie points. [3]