AN INVESTIGATION FOR REAL TIME COMPREHENSIVE SENSOR MODELING

Several commercial high resolution imagery satellites, were successfully launched and several commercial goverment missions in different countries such as US, Russia, France and India scheduled launches of these satellites. Successful exploitation of the high accuracy potential of these systems depends on good mathematical models for the sensor modeling. For real-time applications, simpler image geometry models are often used, requiring much shorter computation times. Depending upon accuracy requirement and image exploitation applications, the rational functions, Direct Linear Transformation (DLT), Self calibration DLT (SDLT), 2D projective, polynomials, 3D affine, multiquadrics and thin plate spline approximate models may be used for real-time positioning. This paper discusses seven non-rigorous sensor models suitable for real-time use, with emphasis on a comprehensive sensor model. The flexibility and good accuracy of the non-rigorous models with a number of US (Ikonos), India (IRS-1C), Russia (KFA- 1000) and French (SPOT 4) sensors with resolution varying from 0.82m to 10 m are demonstrated. The test areas cover parts of north-east, west and south of Iran. Different methods for determining ground control points (GCPs) and independent check points (ICPs) including GPS, digital maps and models after absolute orientation were used.