Abstract:

The Mosaic mode is a hybrid mode of spotlight and ScanSAR, and it can image a large coverage at a high resolution. In the paper, an easily realized Mosaic mode is proposed. In the mode, the beam switching in range is realized by electrical beam steering, whereas the beam steering in azimuth is realized by mechanical beam steering. The agile satellite can realize the mechanical beam steering by pitching maneuver expediently. Thus, it is fit for the implementation of the Mosaic mode. In this paper, a new system design method is presented for the Mosaic mode. Beginning with the broadside position, the nonlinear system in the unknown squint angle and dwell time of the burst is iteratively solved. In this way, the system parameters and timeline of the Mosaic mode are obtained. Moreover, a new approximate computation method for the performance parameters is obtained based on the equivalent  stretch of the azimuth antenna pattern. It can achieve the performance parameters of the Mosaic mode visually and expediently.

Key words: Synthetic aperture radar (SAR); , Agile satellite; , Mosaic mode; , Azimuth steering; , High\, resolution wide swath