Patent ID: 8265817

Claim:
A method of electro-optical absolute attitude determination of a moving object, the method comprising: capturing a frame of image data of a first scene with a detector that measures angles of detected features within the captured frame of image data with respect to the detector's boresight reference relative to the object; identifying at least three features from the captured frame of image data of said first scene by selecting features within the pixel space of the captured frame of image data; computationally correlating said identified features to features in a map to determine corresponding map locations of said identified features and a location of the object within the map; calculating, with a processor, the absolute attitude based on the difference between the locations of the at least three features in the captured frame of image data and the locations of the correlated features in the map by transforming the correlated features from the map into a first set of object space angular coordinates based on the location of the object within the map and the measured angles of the correlated features to generate horizontal, vertical, and arc coordinate values; tracking the at least three features within image data of a second scene captured subsequent to the first scene; measuring first relative changes in position of the at least three features in the second scene with respect to the image data of the first scene; determining, based on the first relative changes in position of the at least three features, a change in attitude of the moving object relative to the at least three features; and calculating, based on a comparison of the determined change in attitude of the moving object against a previously calculated absolute attitude of the moving object, a new absolute attitude and attitude change rate and attitude change direction for the moving object.