A Simplified Approach to Estimate the Area of Interest Coverage Duration Performance for SAR Satellites

Abstract

During the mission design for Synthetic Aperture Radar (SAR) Earth observation satellites, the coverage capabilities are a key parameter for the performance of the system. In addition, they have a direct influence on the further mission concept and the design of an observation scenario. A representative coverage analysis regarding the time to cover relevant targets must be conducted by evaluating the coverage durations for various dimensions of areas of interest (AOIs) in multiple globally distributed locations. For this purpose, common approaches generally achieve comprehensive and precise results but also require cumbersome software configurations to realize a wide variety of scenarios adopting various AOI dimensions and locations. In this paper we therefore introduce a dedicated and simplified approach to estimate the coverage duration performance of a SAR system which can be achieved with few input parameters for various AOIs thus providing an advantage in early stages of the mission design. In this context the presented coverage estimations are performed using basic orbit characteristics, including for example the number of days per repeat cycle or the orbit's inclination and the effective swath width of the SAR system. By evaluating the geometric relations between the AOI and the swath as well as by determining the revisit and access possibilities from the repeat ground-track orbits, the coverage duration is approximated for each AOI dimension. With this methodology the coverage durations for various orbital configurations and swath widths can be analyzed and compared against each other effectively. The results then provide an overview of the coverage duration performance of different configurations and can either be used to derive necessary improvements or to evaluate the current configuration.