Backup Navigation System for Unmanned Aerial Vehicles

An unmanned aerial vehicle (UAV) system comprising:

• a primary navigation system providing for navigation of the UAV;
• an image capture device configured to capture images of an environment of the UAV and a controller, wherein the controller is configured to:
• use the primary navigation system to begin a flight of the UAV along a first flight path to a destination;
• during the flight along the first flight path, operate the image capture device to capture a first set of images of a field-of-view (FOV) of an environment of the UAV;
• analyze the first set of images to identify one or more first visual features within the environment;
• generate a local flight log for the first flight path, wherein the local flight log associates the identified first visual features with location information generated by the primary navigation system;
• and
• detect a failure event involving the primary navigation system of the UAV and responsively:
• (a) capture at least one post-failure image using the image capture device;
• (b) identify, in the at least one post-failure image, one or more second visual features within the environment;
• and
• (c) detect a match between at least one of the second visual features and at least one of the first visual features, and responsively determining, based at least in part on (i) location information for the at least one first visual feature indicated by the local flight log, and (ii) an orientation of the UAV corresponding to the capture of the post-failure image, a current location of the UAV.