ESTIMATING POSITION AND ORIENTATION OF AN UNDERWATER VEHICLE BASED ON CORRELATED SENSOR DATA

• US 20120101715A1
• Filed: 10/25/2011
• Published: 04/26/2012
• Est. Priority Date: 10/25/2010
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Debrunner, Christian H., Tangirala, Sekhar C., Feldman, I, Walter K.
• Granted Patent: US 8,965,682 B2
• Time in Patent Office: Days
• US Class Current: 701/408
• CPC Class Codes: G01C 21/005 with correlation of navigation data from several sources, e.g. map or contour matching G01C21/30 takes precedence
• CPC Class Codes: G01C 21/1656 with passive imaging devices, e.g. cameras

Abstract

A method and system are described that can be used for combining two sources of position and orientation (pose) information where the information from one source is correlated with the information from the other and the sources produce information at differing rates. For example, the method and system allow for estimating position and orientation (pose) of an underwater vehicle relative to underwater structures by combining pose information computed from a 3D imaging sonar with pose information from a vehicle navigation system. To combine the information from the two sources, a determination is made as to whether to generate a forward prediction of the pose estimate of one of the sources relative to the other, and generating the forward prediction if needed. An updated pose of the underwater vehicle is determined based on the fused pose estimate, and which is used for vehicle guidance and control.

Claims

1. A method of estimating position and orientation (pose) of an underwater vehicle comprising:

receiving pose data from one source;

receiving pose data from another source, the data from the another source is correlated with the data from the one source;

combining the data from the one source and the another source, the combination resulting in a fused pose estimate;

determining whether to generate a forward prediction of the data received from either the one source or the another source, and generating the forward prediction if needed; and

determining an updated pose of the underwater vehicle based on the fused pose estimate; and

determining when to and updating the one source or the another source based on the fused pose.

2. The method of claim 1, wherein the one source is a vehicle navigation system of the underwater vehicle that is configured to provide an estimate of the pose of the underwater vehicle.

3. The method of claim 1, wherein the another source is a three dimensional sonar based sensor that is configured to provide three dimensional images of underwater structures and estimates of the pose of the underwater vehicle.

4. The method of claim 2, wherein the step of estimating an updated position comprises correcting drift that may occur in the vehicle navigation system, the correction occurring at a period determined by the correlation time of the fused pose estimate.

5. The method of claim 1, further comprising reinitializing the another source to generate a different pose data that is more accurate and consistent with a current fused pose estimate, the reinitializing comprises performing failure detection processing.

6. The method of claim 2, further comprising resetting a pose of the vehicle navigation system based on the fused pose estimate.

7. The method of claim 1, wherein the underwater vehicle is one of an autonomous underwater vehicle or a remotely operated vehicle.

8. The method of claim 1, wherein the underwater structure is non-stationary.

9. A system for estimating the position or pose of an underwater vehicle comprising:

a sensor onboard an underwater vehicle, the sensor is configured to direct an acoustic sonar wave toward an underwater structure, the reflected acoustic sonar wave being processed to produce an image sensor-based estimate of pose;

a vehicle navigation system onboard the underwater vehicle, the vehicle navigation system is configured to provide an estimate of pose of the underwater vehicle,

the image sensor-based pose estimate provided by the sensor is correlated with the estimate provided by the vehicle navigation system;

a data storage onboard the underwater vehicle that is configured to receive the image sensor-based pose estimate; and

a data processor onboard the underwater vehicle, the data processor is configured to receive both the image sensor-based pose estimate and the estimate from the vehicle navigation system,

the processor is configured to combine the image sensor-based pose estimate provided by the sensor and the estimate provided by the vehicle navigation system, the combination resulting in a fused pose estimate,

the processor configured to determine whether to generate a forward prediction of the image sensor-based pose estimate, and configured to generate the forward prediction if needed, and

the processor configured to determine an updated pose of the underwater vehicle based on the fused pose estimate.