The Study Of New Mode For The Spacebore Synthetic Aperture Radar Techniques

Spaceborne synthetic aperture radar (SAR) systems offer continuing observational capabilities of all-weather, day and night, wide range coverage, even global coverage for any of interesting hotspot area, and that have stronger resistant capability of being wrecked. Along with development of the technology for high resolution SAR, the spaceborne SAR system gradually becomes a research hotspot. People all along aim at high resolution and wide area coverage in spacebore SAR system. More target information can be obtained through high resolution SAR, thereby the ability of identifying targets can be greatly improved. The study of spacebore radar has important significance and wide application prospects of the rapid development of imaging remote sensing techniques.The several new modes for a spaceborne SAR are studied. The summary of researches in this dissertation is as follows:1. According to the requirement of users and the tactical indexes, the technology indexes and the key technologies of the spaceborne SAR are determined, and the mission analysis, design flow chart, orbit option and the formulae of technology indexes of the SAR system are also given.2. The principle of sliding spotlight SAR was studied in detail. The system index, especially, antenna azimuth steering angle etc of sliding spotlight mode are studied. The realization method of the mode is presented, at the same time, the Doppler de-ambiguity, the requirement of azimuth steering angle, and the dwell time of azimuth point targets, and the position of rotation center are analyzed. The simulating results are provided.3. The space-born TOPSAR mode is studied, specially the antenna rotation highly accelerating the speed of antenna footprint. The high azimuth resolution is realized by the azimuth multi-channel antenna in TOPSAR mode. The azimuth steering angle of the antenna and the azimuth steering angle rate of the antenna etc are sufficiently analyzed and simulated. At the same time, the estimate method of beam positions for azimuth multi-channel TOPSAR is presented.4. It mainly introduces the overview and the development tendency of high resolution spaceborne SAR system in the word. The technology approachs that realise high resolution and wide swath of spacebore SAR are presented. And primary project and beam positions estimate of spacebore DBF SAR are also presented.