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一种工作在可见光波段的对地静止轨道卫星高精度偏航地球敏感器工程模型已经开发、设计、制造成功。这种偏航敏感器是一种功能完备的自主地球敏感器,它不需要外接CPU总线就可完成计算,定姿算法已经开发出来,并用气象卫星地球图象进行了试验性验证,这种偏航敏感器包括一个独特而新颖的8位×256×256矩阵探测器IVP-MAPP 2200,它使敏感器变得非常紧凑。算法以图象处理与匹配技术为基础。计算偏航角之前,必须先算出俯仰与滚动角。然后改变卫星位置,使地球像能够处于敏感器芯片中心。敏感器要处理五种地球照明情况:全球照明、半球照明、新月形照明、新月形照明且太阳在视场中、地球完全无照明。在白天,全球照明与半球照明情况下,敏感器搜索地面控制点(GCP),用相关算法计算偏航角。在停晚和夜里,敏感器根据新月形地球的形心与表值相比较来计算偏航角。俯仰与滚动角测量精度为0.015°(全地球照明),偏航角测量精度为0.03°(增量精度)和0.2 °～ 0.5°(绝对精度),具体值视能够见到的地球照明面积而定。太阳在视场中出现,这是这种敏感器的一个潜在问题,因为动态范围太大会产生像晕效应,而有杂散光与叠影则会产生光学问题。不过,当太阳出现在视场中时,可以用降低俯仰与滚动角测量精度的办法来处理。如果看不见地球而只有太阳位置参与计算,就与其他模式相比较。在这种模式下,偏航角计算精度与采样数目有关,当卫星运动参数已知时,必须用多次采样确定太阳像的速度向量。
A geosynchronous high-precision yaw-earth sensor engineering model for the geostationary orbit in the visible wavelength band has been developed, designed and manufactured successfully. This yaw sensor is a fully functional autonomous earth sensor that does not require an external CPU bus to complete the calculation. The attitude and position algorithm has been developed and experimentally validated with a meteorological satellite image of the Earth, The aeronautics sensor includes a unique and innovative IVP-MAPP 2200 8-bit × 256 × 256 matrix detector that makes the sensor very compact. The algorithm is based on image processing and matching techniques. Before calculating the yaw angle, you must first calculate the pitch and roll angle. Then change the position of the satellite so that the Earth can be centered in the sensor chip. The sensor deals with five types of earth lighting: global lighting, hemispherical lighting, crescent lighting, crescent lighting and the sun in the field of view, the earth is completely unaffected. In daylight, global illumination and hemispherical illumination, the sensor searches for ground control points (GCPs) and calculates the yaw angle using the correlation algorithm. In the evening and at night, the sensor calculates the yaw angle based on the centroid of the crescent moon compared to the table value. Pitch and roll angle measurement accuracy of 0.015 ° (global illumination), the yaw angle measurement accuracy of 0.03 ° (incremental accuracy) and 0.2 ° ~ 0.5 ° (absolute accuracy), depending on the specific value of the Earth can see the lighting area and set. The presence of the sun in the field of view is a potential problem with this type of sensor because the dynamic range is too large to produce a halo effect while the presence of stray light and overlay causes optical problems. However, when the sun appears in the field of view, it can be dealt with by reducing the pitch and roll angle measurement accuracy. If you can not see the Earth and only the sun’s position in the calculation, compared with other modes. In this mode, the accuracy of the yaw angle is related to the number of samples. When the parameters of the satellite are known, multiple samples must be used to determine the speed vector of the solar image.