High Precision Positioning of Unmanned Helicopter with Area Array Images

To improve the accuracy of unmanned helicopter, geometry calibration is compulsory. Direct geo-reference experiment is first carried out to verify system's accuracy without any calibration; and then the free network bundle adjustment experiment is undertaken to verify the positioning accuracy of the system without ground control points; finally, a self calibration bundle adjustment is undertaken to calibrate and compensate the camera distortion, interior elements changes, IMU alignment angle. Experimental results show that the unmanned helicopter has high positioning accuracy. The accuracy of direct geo-reference can meet the requirements of emergency mapping, and can be aided by a few ground control points, the positioning accuracy is much better than that of 1:500 mapping requirements, which can be used for conventional surveying and mapping production. After system error compensation, the direct geo-reference accuracy has improved significantly:the planar accuracy has improved by 46.37% and the height accuracy has improved by 62.49%. The flight test of Songshan calibration field shows that the method of calibration and compensation is correct and effective, and the unmanned helicopter has a good prospect for surveying and mapping applications.