Application of GPS-supported Aerotriangulation in Large Scale Topographic Mapping Based on Low-altitude Photogrammetry

We describe briefly the basic principle of GPS-supported low-altitude photographic system developed by the authors.A set of actual aerial images with airborne GPS data,at a ground sample distance of 10 cm,were taken from Yicheng site in China by our system.The empirical results have verified that the accuracy of the GPS-supported bundle block adjustment with 4 XYZ ground control points around the corners of the block area is very close to that of the conventional self-calibration bundle block adjustment with additional parameters,which leads to more than 90% reduction in field survey for ground control points.And the object coordinate accuracies of the stereo models reconstructed using the photogrammetric points obtained by GPS-supported bundle block adjustment are better than ±20 cm for planimetry and ±15 cm for elevation,which meets the specification of topographic mapping at 1∶500 scale flat.This shows the ample applicability and the economic benefit of GPS-supported bundle block adjustment in low-altitude photogrammetry.