一种敏捷卫星积分时间计算方法

An integral time calculation method for agile satellite

敏捷卫星成像过程中姿态变化灵活,积分时间变化剧烈,传统卫星积分时间计算模型已无法满足精度要求。因此,提出一种改进的积分时间计算模型,在星地斜距计算和摄影点地速计算两方面作了改进。星地斜距计算时利用地表数字高程模型修正理论的斜距值,摄影点地速计算中增加姿态角速度对卫星本体坐标系角速度矢量的影响,并设计了整个算法在星上数管分系统中的实现方案。最后在星载嵌入式环境下进行了仿真计算,并与地面仿真计算结果进行了比对分析。两者比对偏差在0.01‰以内,可以满足相机成像质量要求。

Traditional integral time calculation models can′t satisfy the accuracy requirement,because attitude flexibility and integral time change severely during the imaging of agile satellite.An integral time calculation model was proposed to improve the aspects of ground velocity calculation of imaging point and height calculation from satellite to ground point.Digital elevation model was adopted to correct height value for height calculation from satellite to ground point.And the attitude angular velocity′s impact to angular velocity vector in the satellite body coordinate system was considered when calculated the ground velocity at imaging points.The whole algorithm implementation on OBDH subsystem was designed and simulation calculation under the embedded environment was conducted.The analysis results manifests the method can meet the accuracy requirement of agile satellite camera imagingquality since the difference is within 0.01‰ by comparison with STK simulation calculation results.