Abstract:

In order to meet the requirement of high revisit and wide coverage of SAR system for national disaster prevention and reduction, the world’s first geosynchronous orbit SAR named Land Exploration 4rd(LT-4) was designed and developed. The satellite uses a ring-shaped reflector antenna and combined with phased array feed system, operating at L-band. The particularity of the orbit makes the satellite naturally have the characteristics of high revisit and wide coverage. In order to give a comprehensive description of the SAR payload system of LT-4, the characteristics of high orbit SAR which are different from low orbit SAR are described, and the key performance parameters of SAR payload are given. Then the working process of SAR payload is introduced, and the main functions and performance of the key equipment of SAR payload are expounded. At last, the history of load development for more than ten years is briefly described, and the load integration test items and test verification are given. The world's first high-orbit SAR image is obtained when the SAR payload works for the first time on orbit. The image information is rich and the payload’s on-orbit state is stable. The imaging results show that the SAR payload design is reasonable and the ground test and verification are sufficient, which can provide favorable information support for national disaster prevention and reduction.

Key words: LT-4, geostationary orbit, load design, integration testing