New Geo-location Approach Based on Camera Coordinates and Common Points on Multiple Images

Abstract

The accuracy of traditional unmanned aerial vehicle (UAV) geo-location based on single image is too low to meet the needs of precise strike. In this paper, a new UAV geo-location method is presented. The mathematical models are constructed by linearization of the collinearity equations to iteratively compute the pose angles and focal length of the camera. At least three images of the target, along with at least three identifiable common points among the images, are needed for reckoning camera pose angles and focal length. The three dimensional (3D) coordinates of ground target are calculated using forward intersection. The new method can get the target coordinates with no dependence on digital elevation model (DEM) and the measured values of camera pose angles, therefore two of the three primary error sources in the traditional UAV target location approach are eliminated. Simulation and real image experiment results show that the accuracy of the estimated target location is close to that of the UAV position, and that target location error is within 5m circular error probable (CEP) on condition that the UAV is navigated by differential global positioning systems (DGPS).

Defence Science Journal, 2009, 59(1), pp.43-48, DOI:http://dx.doi.org/10.14429/dsj.59.1483