Method and system for GPS-denied navigation of unmanned aerial vehicles

• US 8,315,794 B1
• Filed: 09/05/2006
• Issued: 11/20/2012
• Est. Priority Date: 09/05/2006
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Strelow, Dennis W., Touchberry, Alan B.
• Primary Examiner(s): Jen, Ian
• Application Number:
  US11/470,152
• Time in Patent Office: 2,268 Days
• Field of Search: 701/24, 701/3, 701/4, 382/154, 382/294, 382/173
• US Class Current: 701/412
• CPC Class Codes: G05D 1/104 involving a plurality of aircrafts, e.g. formation flying traffic control systems for aircraft G08G5/00

Abstract

A method and system for navigation of one or more unmanned aerial vehicles in an urban environment is provided. The method comprises flying at least one Global Positioning System (GPS)-aided unmanned aerial vehicle at a first altitude over an urban environment, and flying at least one GPS-denied unmanned aerial vehicle at a second altitude over the urban environment that is lower than the first altitude. The unmanned aerial vehicles are in operative communication with each other so that images can be transmitted therebetween. A first set of images from the GPS-aided unmanned aerial vehicle is captured, and a second set of images from the GPS-denied unmanned aerial vehicle is also captured. Image features from the second set of images are then matched with corresponding image features from the first set of images. A current position of the GPS-denied unmanned aerial vehicle is calculated based on the matched image features from the first and second sets of images.

Claims

1. A method for navigation of one or more unmanned aerial vehicles in an urban environment, the method comprising:

flying a first unmanned aerial vehicle at a first altitude over an urban environment such that the first unmanned aerial vehicle is aided by Global Positioning System (GPS) signals;

flying a second unmanned aerial vehicle at a second altitude over the urban environment that is lower than the first altitude such that the second unmanned aerial vehicle is denied access to GPS signals, wherein the first and second unmanned aerial vehicles are in operative communication with each other so that images can be transmitted therebetween;

capturing a first set of images of a selected area in the urban environment from the first unmanned aerial vehicle, the first set of images having one or more image features;

capturing a second set of images of the selected area in the urban environment from the second unmanned aerial vehicle, the second set of images having one or more image features that correspond to the one or more image features in the first set of images;

matching the one or more image features from the second set of images with corresponding image features from the first set of images; and

calculating a current position of the second unmanned aerial vehicle based on the matched image features from the first and second sets of images.

2. The method of claim 1, wherein the first set of images is captured by one or more cameras on the first unmanned aerial vehicle.

3. The method of claim 1, wherein the second set of images is captured by one or more cameras on the second unmanned aerial vehicle.

4. The method of claim 1, wherein the image features from the second set of images are matched with image features from the first set of images by a method comprising:

estimating inertial position of the second unmanned aerial vehicle;

cueing based on salient image features to detect matches between the second set of images and the first set of images; and

providing epipolar constraints between images to correctly establish image correspondences.

5. The method of claim 4, wherein the inertial position is estimated based on input from one or more inertial sensors on the second unmanned aerial vehicle.

6. The method of claim 5, wherein the inertial sensors comprise one or more gyroscopes, accelerometers, or combinations thereof.

7. The method of claim 1, wherein the urban environment has an urban canyon.

8. The method of claim 1, wherein the first unmanned aerial vehicle comprises a hover-capable aerial vehicle or a fixed-wing aerial vehicle.

9. The method of claim 1, wherein the second unmanned aerial vehicle comprises a hover-capable aerial vehicle or a fixed-wing aerial vehicle.

20. A non-transitory computer readable medium having instructions stored thereon for a method of navigation of one or more unmanned aerial vehicles in an urban environment according to claim 1.

10. A system for navigation of one or more unmanned aerial vehicles in an urban environment, the system comprising:

means for capturing a first set of images of a selected area in an urban environment from a GPS-aided first unmanned aerial vehicle flying at a first altitude over the urban environment, the first set of images having one or more image features;

means for capturing a second set of images of the selected area in the urban environment from a second unmanned aerial vehicle at a second altitude over the urban environment that is lower than the first altitude such that the second unmanned aerial vehicle is denied access to GPS signals, the second set of images having one or more image features that correspond to the one or more image features in the first set of images, wherein the first and second unmanned aerial vehicles are in operative communication with each other so that images can be transmitted therebetween;

means for matching the one or more image features from the second set of images with corresponding image features from the first set of images; and

means for calculating a current position of the second unmanned aerial vehicle based on the matched image features from the first and second sets of images.

11. The system of claim 10, wherein the means for capturing the first set of images comprises one or more cameras on the GPS-aided first unmanned aerial vehicle.

12. The system of claim 10, wherein the means for capturing the second set of images comprises one or more cameras on the second unmanned aerial vehicle.

13. The system of claim 10, further comprising one or more inertial sensors on the second unmanned aerial vehicle.

14. The system of claim 13, wherein the inertial sensors comprise one or more gyros, accelerometers, or combinations thereof.

15. The system of claim 10, further comprising one or more GPS sensors on the unmanned aerial vehicles.

16. The system of claim 10, wherein the GPS-aided first unmanned aerial vehicle comprises a hover-capable aerial vehicle or a fixed-wing aerial vehicle.

17. The system of claim 10, wherein the second unmanned aerial vehicle comprises a hover-capable aerial vehicle or a fixed-wing aerial vehicle.

18. A non-transitory computer readable medium having instructions stored thereon for a method of navigation of one or more unmanned aerial vehicles in an urban environment, the method comprising:

capturing a first set of images of a selected area in an urban environment from a GPS-aided first unmanned aerial vehicle flying at a first altitude over the urban environment, the first set of images having one or more image features;

capturing a second set of images of the selected area in the urban environment from a second unmanned aerial vehicle at a second altitude over the urban environment that is lower than the first altitude such that the second unmanned aerial vehicle is denied access to GPS signals, the second set of images having one or more image features that correspond to the one or more image features in the first set of images, wherein the first and second unmanned aerial vehicles are in operative communication with each other so that images can be transmitted therebetween;

matching the one or more image features from the second set of images with corresponding image features from the first set of images; and

calculating a current position of the second unmanned aerial vehicle based on the matched image features from the first and second sets of images.

19. The non-transitory computer readable medium of claim 18, wherein the image features from the second set of images are matched with image features from the first set of images by a method comprising:

estimating inertial position of the second unmanned aerial vehicle;

cueing based on salient image features to detect matches between the second set of images and the first set of images; and

providing epipolar constraints between images to correctly establish image correspondences.