A Camera Calibration Method Based on Differential GPS System for Large Field Measurement

Aiming at the problem that the traditional space control point cannot be laid in the large field of view when calibrate the camera’s parameters, a high precision calibration method of the camera is proposed. In this paper, the rover part of the differential GPS system is loaded on the unmanned aerial vehicle (UAV) and the base part is placed at the origin of the world coordinate system. The UAV is controlled to move within the field of view of the camera which to be calibrated and we can obtain the three-dimensional coordinates of the control point and the corresponding image coordinate. And then according to the “High Accuracy Calibration Method Based on Collinear Equation” to calculate the initial value of the camera’s internal and external parameters, and finally we can solve the accurate calibration parameters after optimization. The measurement accuracy of differential GPS system can reach centimeter level, the control points should distributed evenly in the field of view to solve the exact results. Experiments show that the accuracy of the intersection of 300 m and 800 m can reach 0.6 m and 1 m respectively, so the method have the characteristics of high precision, practicality and simple operation.