Evaluation of cartosat-1 satellite triangulation & DSMs in varied terrain conditions

摘要

Digital surface models (DSMs) and Digital elevation models (DEMs) has become inevitable input for many applications including various types of modeling problems besides photogrammetric product generation such as orthoimages and visualization. Automatically generated DSMs using image matching techniques are an efficient means to extract bare earth DEMs or DTMs for various applications including modeling. This paper highlights and evaluates the accuracy of satellite triangulation, and DEM generated from Cartosat-1 data by using Rational Polynomial Coefficient's (RPC's) provided with the Cartosat-1 data along with ground control points (GCPs) collected through differential Global Positioning System (DGPS) surveys. Three study sites were taken for evaluation of DSMs in different topographic conditions, namely, a) Dehradun, Uttarakhand characterized by relatively high undulating terrain comprising of shivalik hills in the south and higher Himalayas on the north, b) Jaipur, Rajasthan having more of urban and plain agriculture area with Aravalli ranges, and c) Kendrapara, Orissa which is having a plain terrain conditions with agriculture fields, river, and sparsely populated area. DGPS surveys were conducted at the three sites to collect ground control points (GCPs) for satellite triangulation & subsequent analysis. The satellite triangulation resulted in RMSE of better than a pixel for all the three sites. The RMSE for DEM is varying from within a pixel for plain area to about four pixels for highly undulating terrain. The paper describes the positional and vertical accuracies achieved for cartosat-1 stereo data through photogrammetric process of satellite triangulation and Digital surface model generation in the three study sites having different topographic conditions.