Available Technology

A Nonlinear Estimation Approach to Real-Time Georegistration from Aerial Images

The nonlinear estimation algorithm is based on a linearized Kalman filter structure that carries 19 states in its current implementation. Six (6) of the 19 states are calibration parameters associated with the initial camera pose (i.e., position (3) and attitude (3) of the camera at the time instant of the very first image). One (1) of the states calibrates the scale factor associated with all camera-derived information. The remaining 12 states are used to model the current kinematic state of the vehicle (position (3),velocity (3), acceleration (3), and attitude (3)).The new georegistration approach was validated by computer simulation based on an aircraft flying at a speed of 70 m/s in a 3 km radius circle at an altitude of 15,000 feet, using a camera pointed at the ground toward the center of the circle. Results from using the nonlinear estimation algorithm in combination with GPS and camera images taken once per second, indicate that after 20 minutes of operation, real-time georegistration errors are reduced to values of less than 2 meters, 1-sigma, on the ground.
Internal Laboratory Ref #: 
NPO-47255-1
Patent Status: 
U.S. Government Purpose Release
Agency
NASA
Region
Far West
State: 
California
Lab Representatives
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