天绘二号卫星工程设计与实现

TH-2 satellite engineering design and implementation

天绘二号卫星系统是我国首个基于干涉合成孔径雷达技术的微波测绘卫星系统,也是我国第1个近距离编队卫星系统,是国际上继德国TanDEM-X系统后的第2个微波干涉测绘卫星系统,并在国际上首次提出了通过设计双频成像解决干涉相位绝对模糊问题的方法,彻底摆脱了对地面控制数据的依赖。该系统工作于X频段,设计分辨率为3 m,处于500 km的太阳同步轨道,由两颗对等的卫星组成,采用异轨道面卫星编队、一发双收雷达收发模式的技术体制,可以快速测制全球数字表面模型和雷达正射影像。本文通过对干涉基线体制、卫星编队构型及雷达收发模式的选择,提出了天绘二号卫星技术体制;并从系统任务、主要性能及组成3个方面进行了工程设计;从总体论证、关键技术攻关及验证、型号研制3个阶段阐述了工程实现情况;最后介绍了卫星系统在轨测试验证情况。测试结果表明,所有指标达到了工程设计要求,产品精度与TanDEM-X系统相当,满足1∶5万比例尺测图精度要求,从而验证了天绘二号卫星工程设计思路正确,工程实现的方法合理可行。

The TH-2 satellite system is China’s first microwave surveying satellite system based on interferometric synthetic aperture radar technology,and is also China’s first short-range formation satellite system.It is the second microwave interferometric surveying satellite system after the German’s TanDEM-X system in the world.A method to solve the problem of absolute ambiguity in the interference phase by designing dual-frequency imaging is proposed for the first time in the world,which completely got rid of the dependence on ground control data.The system works in the X band,with the resolution of 3 m and a solar synchronous orbit of 500 km.It is composed of two equal satellites.It adopts a technical system of satellite formation in different orbits and a bistatic radar transceiver mode.It can measure the global digital surface models and acquire radar orthophotos in a short time.In this paper,through the selection of the interference baseline system,satellite formation configuration and radar transceiver mode,the technical system of TH-2 satellite is proposed.The engineering design is carried out from three aspects:system mission,main performance and composition.The implementation of the project is expounded from the three stages of the overall demonstration,the key technical research and verification,and project development.Finally,the on-orbit test and verification of the satellite system is introduced.Test results show that all indicators have reached the requirements of engineering design,products’precision is equivalent to TanDEM-X system and can meet the 1∶50000 scale mapping accuracy.These verify the TH-2 satellite’engineering design ideas correct and the method of project implementation reasonable and feasible.