Back to results
US 8,265,817 B2Granted
Inertial measurement with an imaging sensor and a digitized map
AssigneeLockheed Martin Corporation
InventorsGene D. Tener, Andrew H. Hawkins, Mark A. Bovankovich, Louis N. Glaros
Life of this patent
Estimating the term…
Abstract
The present invention relates to a system and method for determining vehicle attitude and position from image data detected by sensors in a vehicle. The invention uses calculated differences between the locations of selected features in an image plane and the location of corresponding features in a terrain map to determine the attitude of the vehicle carrying the sensors with respect to a ground frame of reference.
Claims26
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.
8 more elements
A device for electro-optically determining absolute attitude of a moving object, the device comprising:
- an imaging sensor that captures a frame of image data of a first scene and that measures the angles of detected features within the captured frame of image data with respect to the sensor's boresight reference relative to the object;
- a feature identification unit that identifies at least three features in captured frame of image data, the feature identification unit comprising
- a feature selection unit that selects features within the pixel space of the captured frame of image data;
- and
- a feature correlation unit that correlates said identified features to a map;
- a feature location unit that determines corresponding map locations of the correlated features and a location of the object within the map;
- and
- an attitude calculator that calculates the absolute attitude based on the difference in the locations of at least three features in the frame of image data and the locations of the correlated features in the map, the attitude calculator comprising
- a space transformation module that transforms 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;
- a feature tracker that tracks the at least three features within image data of at a second scene captured subsequent to the first scene;
- a relative position computer that measures relative changes in position of the at least three features in the second scene with respect to the image data of the first scene, and determines, based on the relative changes in position of the at least three features, the change in attitude of the moving object relative to the at least three features;
- and
- a movement and position calculator that calculates, 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.
10 more elements
Dependencies are inferred from the claim text.