关键词: 陆地探测四号01星, 高轨, 合成孔径雷达, 大功率, 大口径

Abstract: In order to solve the problem of small imaging width and long revisiting time of low orbit SAR,China developed the No.4 land exploration satellite 01,which is a scientific satellite in the medium and long term development plan of national civil space infrastructure (2015-2025),and is the world′s first geosynchronous SAR satellite.Using the advantages of the geosynchronous orbit,the revisiting time of the same place can be reduced from the day level of low orbit satellite to the hour level,and the width can be increased from the hundred-kilometer level of low orbit satellite to the thousand-kilometer level,which can provide strong support for the effective implementation of disaster emergency response.For the new system of geosynchronous SAR microwave imaging,a series of key technologies are developed,such as microwave imaging for geosynchronous SAR,ultra-large power space-borne microwave transmission,ultra-large aperture space-borne antenna,large-flexibility and high-precision attitude stability control,intense pulse high-quality large power supply,integrated efficient thermal management for payload and platform,and integrated satellite-ground high-precision orbit determination.The satellite has the capability of quick revisit,large width,all-day and all-weather observation.The overall design of the satellite is introduced,and the technical innovation is summarized.Through the evaluation of the preliminary test results for the satellite in orbit,the geosynchronous SAR images have clear texture and good quality,which can meet the requirements of disaster prevention and reduction,land resource exploration and other tasks.

Key words: No.4 land exploration satellite 01, geosynchronous orbit, synthetic aperture radar, large power, large aperture