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为准确获取摄影区域地理位置信息,针对时间延迟积分电荷耦合器件(TDI-CCD)全景式航空相机未配备激光测距仪的情况,提出一种直接对地目标定位算法。依据机载定位定向系统(POS)测量的载机位置、姿态信息以及航空相机中编码器测量的俯角、位角信息,利用齐次坐标变换求解成像系统视轴(LOS)在地理坐标下的指向角以WGS-84坐标系下定义的地球椭球模型为基础,利用地球椭球计算理论确定目标区域经纬度信息。采用蒙特卡罗方法仿真分析了载机姿态角测量误差以及相机俯角、位角误差对视轴指向角计算精度的影响;着重分析了摄影倾斜角和目标区域地形起伏对对地目标定位精度的影响,指出摄影倾斜角和目标区域地形起伏越小,定位精度越高。采用飞行实验验证了该对地目标定位算法的有效性,在飞行高度为17750m,摄影倾斜角在63°~75°范围内,对地目标定位圆概率误差小于212.96m,可满足工程实际需要。
In order to accurately obtain the geographic location information of the photography area, aiming at the situation that the TDI-CCD panoramic camera is not equipped with a laser range finder, a direct target location algorithm is proposed. According to the position and attitude information of the aircraft and the depression and azimuth angles measured by the encoder in the aerial camera, the homogeneous coordinate transformation is used to find the orientation of the LOS in the geographic coordinates Based on the Earth ellipsoid model defined in the WGS-84 coordinate system, the earth ellipsoid calculation theory is used to determine the latitude and longitude information of the target area. The Monte Carlo method was used to simulate the influence of attitude errors on camera attitude and the angle and angle error of camera on the calculation accuracy of the angle of view. The impact of camera tilt angle and the undulation of the target area on the positioning accuracy of the target was analyzed emphatically , Pointed out that the smaller the imaging tilt angle and the relief of the terrain in the target area, the higher the positioning accuracy. The validity of the target location algorithm is verified by flight experiments. The flight error is less than 212.96m when the flight altitude is 17750m and the photographic inclination angle is in the range of 63 ° ~ 75 °, which can meet the actual engineering needs.