AUTONOMOUS COLLISION AVOIDANCE SYSTEM FOR UNMANNED AERIAL VEHICLES

• US 20130124020A1
• Filed: 01/04/2013
• Published: 05/16/2013
• Est. Priority Date: 06/18/2004
• Status: Active Grant

• Current Assignee: L3 Technologies, Inc. (L3Harris Technologies, Inc.)
• Original Assignee: L-3 Unmanned Systems, Inc. (L3Harris Technologies, Inc.)
• Inventors: Duggan, David S., Felio, David A., Askew, Craig S.
• Granted Patent: US 8,700,306 B2
• Time in Patent Office: Days
• US Class Current: 701/3
• CPC Class Codes: G05D 1/106 Change initiated in response to external conditions, e.g. avoidance of elevated terrain or of no-fly zones
• CPC Class Codes: G08G 5/0069 specially adapted for an unmanned aircraft
• CPC Class Codes: G08G 5/0086 for monitoring terrain radar or analogous systems specially adapted for terrain avoidance G01S13/935
• CPC Class Codes: G08G 5/045 Navigation or guidance aids, e.g. determination of anti-collision manoeuvers radar or analogous systems specially adapted for anti-collision between aircraft G01S13/933

Abstract

Autonomous collision avoidance systems for unmanned aerial vehicles are disclosed. Systems illustratively include a detect and track module, an inertial navigation system, and an auto avoidance module. The detect and track module senses a potential object of collision and generates a moving object track for the potential object of collision. The inertial navigation system provides information indicative of a position and a velocity of the unmanned aerial vehicle. The auto avoidance module receives the moving object track for the potential object of collision and the information indicative of the position and the velocity of the unmanned aerial vehicle. The auto avoidance module utilizes the information to generate a guidance maneuver that facilitates the unmanned aerial vehicle avoiding the potential object of collision.

Claims

1. A method for autonomously controlling a vehicle so as to avoid potential collisions, the method comprising:

detecting and tracking potential objects of collision by identifying directional finding angle information;

determining that at least one of the potential objects of collision will enter a path of the vehicle;

guiding the vehicle out of the path; and

wherein said determining and guiding are based on the directional finding angle information and a navigational state of the vehicle.

2. The method of claim 1, wherein guiding the vehicle out of the path comprises putting the vehicle on a different path that allows the vehicle to miss the object of collision by at least a predetermined miss distance.

3. The method of claim 1, wherein determining comprises calculating a relative range, a relative range rate, a line of sight angle and a line of sight rate between the potential objects of collision and the vehicle based on the directional finding angle information and navigational states of the vehicle.

4. The method of claim 3, wherein the line of sight angle is based on a trigonometric function of the relative range.

5. The method of claim 3, wherein the line of sight rate is a function of the relative range and the relative range rate.

6. The method of claim 2, wherein guiding the vehicle comprises determining a zero effort miss distance, wherein the zero effort miss distance is a function of the line of sight rate, a closing velocity and an amount of time until the vehicle has reached the closest point of approach to the object of collision.

7. The method of claim 1, and further comprising:

activating an alert flag based at least in part upon a determination that the vehicle is on course to enter within the predetermined distance relative to the potential object of collision; and

altering the course of the vehicle based at least in part on the activation of the alert flag.

8. The method of claim 7, wherein the alert flag provides an indication of whether the vehicle is on course to collide head-on with the potential object of collision or whether the vehicle is on course to enter into another type of collision with the potential object of collision.

9. The method of claim 7, wherein altering the course comprises calculating a waypoint leg to alter the course of the vehicle.

10. The method of claim 1, and further comprising returning the vehicle to a previous guidance mode by restoring a previous course of the vehicle after the vehicle has avoided the potential object of collision.

11. A system for controlling an unmanned aerial vehicle to avoid potential collisions comprising:

a detect and track module configured to identify and track potential objects of collision;

an avoidance module configured to calculate navigational states of the potential objects of collision relative to the vehicle to determine if at least one of the potential objects of collision will enter a path of the vehicle; and

a guidance module configured to guide the vehicle out of the path based on the calculated navigational states.

12. The system of claim 11, wherein the detect and track module is configured to optically identify and track potential objects of collision by identifying directional finding angle information.

13. The system of claim 11, wherein the avoidance module comprises a track state estimator configured to estimate a relative range, a relative range rate, a line of sight angle and a line of sight rate between the potential objects of collision and the vehicle.

14. The system of claim 13, wherein the avoidance module comprises an avoid state calculator configured to calculate the navigational states of the potential objects of collision relative to the vehicle based on estimations made by the track state estimator.

15. The system of claim 14, wherein the avoid state calculator is configured to calculate the closest point of approach between the vehicle and the potential object of collision.

16. The system of claim 15, wherein the avoidance module further comprises an avoid alert calculator configured to output an alert flag if the calculated closest point of approach indicates that one of the potential objects of collision will enter the path of the vehicle.

17. The system of claim 11, wherein the guidance module further configured to restore the vehicle to a previous guidance mode after the vehicle has successfully avoided the object of collision.

18. The system of claim 11, and further comprising flight controls configured to receive guidance commands from the guidance module.

19. The system of claim 11, wherein the avoidance module includes an auto avoid recovery unit configured to generate a recovery command, the recovery command returning the unmanned aerial vehicle to a previous guidance mode.

20. The system of claim 11, wherein the avoidance module includes a track state estimator configured to receive a moving object track in a form of an elevation angle and an azimuth direction finding angle.