静电式重力梯度测量卫星设计中几个关键问题的理论与方法研究

Satellite gravity measurement is one of new hot topics for geodetic measurements in 21st century.There are great successes which have been achieved by gravity exploring satellites of CHAMP, GRACE and GOCE. And there have some gaps in design theory and practice for special gravity satellite technology in China compared to ESA and NASA. The main objective of this project is to research the principle and method for relevant key points in the system design of gravity gradient satellite based on electrostatic gravity gradiometer as follows: .1)To develope new methods to calculate the non-consavarive force and moments from rarefied gas dynamics in the orbit of 300km and to design the specific configuration of satellite based on the rarefied gas dynamics, then to investigate and analyse the effects of non-consavative forces including atmosphere drag, solar radiation pressure，etc, and found the residual error model of the compensation of non-consavative forces. Finally, to obtain the specific configuration of satellite base on the rarefied gas dynamics, and analyse and found techinical index system of drag free control by numerical and semi-physical simulation..2)To reveal how the performances of gravity gradiometer are affected by mechanical and thermal environment disturbances including position, radial, mass distribution, temperature variation, coordinate frame deformation and so on, then to put forward corresponding environments control methods to suppress these effects in high precision..3)To develop an in-orbit internal calibration method by the means of the thrust forces, the centrifugal forces due to the satellite rotation motions, and the gravitation forces, according to the requirements of in-orbit internal calibration of accelerometer parameters, and finally to propose the in-orbit internal calibration scheme..These results will provide an academic and technical guide for us to design and develop gravity gradiometry satellite. .At the same time, some experiences and critical results have been achieved by applicant's team in the field of gravity exploring satellites.

卫星重力测量是21世纪大地测量研究的新热点，欧美已经发射了CHAMP、GRACE、GOCE卫星，取得极大成功，我国在重力卫星系统设计与实践方面尚有较大差距。本项目旨在对基于高精度静电重力梯度仪的重力梯度卫星设计中几个关键问题的理论和方法进行研究：1）发展一种300km轨道稀薄大气动力学计算方法和卫星特殊气动构型寻优设计方法，深入进行大气阻力、太阳光压等非保守力的影响分析和估计，构建残余非保守力误差模型，进而设计出卫星最佳气动构型，论证无拖曳控制技术指标体系；2）揭示卫星机械、温度、质心、坐标系转换等误差对重力梯度测量的影响与耦合机理，提出高精度控制方法；3）分析高精度静电重力梯度仪在轨校准需求，揭示通过推力器推力、旋转卫星、引力等进行在轨内部校准的机理，建立新的在轨内部校准方法。研究成果将为我国自主研制重力梯度卫星提供理论和方法指导。申请人及课题组具有较好的重力卫星设计和关键技术攻关基础。

重力梯度测量卫星系统精度高，设计难度大。本项目针对重力梯度测量卫星设计中的若干关键问题进行了理论和方法研究，研究内容主要有：重力梯度卫星系统级技术指标定量分析研究、超低轨稀薄大气气动阻力/力矩计算方法研究、重力梯度卫星姿态与无拖曳控制方法研究、重力梯度卫星高稳定性机热技术与方法研究、重力梯度卫星在轨标定理论与方法研究。取得的主要结果包括：1）利用半解析分析方法，揭示了卫星科学目标与系统级参数之间的定量关系，对卫星方案论证和设计具有重要的指导意义；2）发展了一种基于试验粒子Monte Carlo方法(test particle Monte Carlo, TPMC)的超低轨道稀薄大气气动力/力矩计算方法，开发了计算软件，设计了卫星的特殊气动构型；3）定量分析了无拖曳控制、卫星高稳定结构、高稳定热控对重力梯度测量任务的影响，提出了相应的技术途径，进行了仿真验证；4）攻克高稳定碳碳夹芯板结构工艺，研制了高稳定碳碳夹芯结构样件；5）对重力梯度卫星在轨标定进行了理论分析，提出了卫星质心和静电加速速度计标度因子及零偏误差的标定方法。本项目首次针对重力梯度测量卫星设计中的若干理论和方法，取得的成果，对今后我国进行重力梯度卫星的方案论证和系统设计具有重要的意义。