Abstract: A method of guidance for an aircraft includes obtaining relative position data indicative of a direction from a location of the aircraft to a location of a moving target point. The method also includes determining, based on the relative position data, a location of a virtual leader based on projecting the location of the aircraft onto a virtual leader path, where the virtual leader path corresponds to a straight approach path to the location of the moving target point along a desired approach direction. The method further includes determining, based on the location of the virtual leader, a guidance input to cause the aircraft to follow the virtual leader.

Abstract: In an example, an unmanned aerial vehicle (UAV) is disclosed, which includes an avionics system, a propulsion system, vertical-lift rotors, and a controller. The controller performs operations including, in response to detecting loss of operation of the propulsion system, determining energy and time constraints based on (i) a remaining avionics battery life and (ii) a remaining rotor battery life. The operations also include using a rotor edgewise inflow model stored on the controller, evaluate parameters for a glide descent trajectory and subsequent rotor-powered flight trajectory to a candidate landing site, to determine whether, based on evaluation of the parameters, an estimated energy consumption during the rotor-powered flight trajectory and time needed for the UAV to land at the candidate landing site exceed the constraints.

Abstract: Aircraft guidance with transmitting beacons is disclosed. An example apparatus includes a transceiver of an aircraft to receive signals from deployed beacons, a signal analyzer to analyze the signals to determine distances of the respective beacons relative to the aircraft, and a position calculator to calculate a positional zone of the aircraft based on the distances.

Abstract: Methods and apparatus to recover rotorcraft are disclosed. A disclosed example apparatus includes a rotor of a vehicle, a rotatable hub to support the rotor, and a rotor hook disposed on the rotor. The rotor hook has a groove to receive a recovery line. The rotor is to contact the recovery line when the vehicle is flown toward the recovery line.

Abstract: Aircraft guidance with transmitting beacons is disclosed. An example apparatus includes a transceiver of an aircraft to receive signals from deployed beacons, a signal analyzer to analyze the signals to determine distances of the respective beacons relative to the aircraft, and a position calculator to calculate a positional zone of the aircraft based on the distances.

Abstract: Methods and apparatus to guide an unmanned aerial vehicle for recovery thereof are disclosed. A disclosed example apparatus includes a sensor at or proximate a tether line, the sensor to measure at least one parameter of an aircraft while the aircraft is in flight and provide sensor output corresponding to a position of the aircraft, and a transceiver to transmit data corresponding to the position to the aircraft for guiding the aircraft to engage the tether line for recovery of the aircraft or a payload carried by the aircraft.

Abstract: Unmanned aerial vehicles including wing capture devices and related methods are disclosed. An example unmanned aerial vehicle includes a fuselage and a wing assembly, the wing assembly including a shoulder coupled to the fuselage, the shoulder including a joint, the joint distal to the fuselage, a wing coupled to the joint, and a hook, the hook coupled to the shoulder, the hook including a groove to receive a cable to arrest flight of the unmanned aerial vehicle.

Abstract: Methods and apparatus to recover rotorcraft are disclosed. A disclosed example apparatus includes a rotor of a vehicle, a rotatable hub to support the rotor, and a rotor hook disposed on the rotor. The rotor hook has a groove to receive a recovery line. The rotor is to contact the recovery line when the vehicle is flown toward the recovery line.

Abstract: Methods and apparatus to recover rotorcraft are disclosed. A disclosed example apparatus includes a rotor of a vehicle, a rotatable hub to support the rotor, and a rotor hook disposed on the rotor. The rotor hook has a groove to receive a recovery line. The rotor is to contact the recovery line when the vehicle is flown toward the recovery line.

Abstract: A method, apparatus, system, and computer program product for controlling landing of a vertical landing vehicle. In one illustrative example, a method controls landing of a vertical landing vehicle. A landing profile for landing the vertical landing vehicle is determined by the computer system using a third derivative of a position equation, an initial position, an initial speed, a final speed, and a touchdown point for the vertical landing vehicle. Landing of the vertical landing vehicle is controlled using the landing profile.

Abstract: Apparatus and methods for controlling an aircraft and/or a vehicle are described. A vehicle speed and direction are received. A wind-over-vehicle speed and direction of wind at the vehicle are measured. An aircraft ground speed and direction are received. An aircraft-relative-to-vehicle speed and an aircraft-relative-to-vehicle direction are calculated based on the aircraft ground speed and direction and the wind-over-vehicle speed and direction. A wind-over-vehicle envelope is calculated based on system design limits for retrieving the aircraft at the vehicle. The wind-over-vehicle envelope maps limits of wind-over-vehicle speeds over a range of directions that enable retrieval of the aircraft at the vehicle. The aircraft and/or the vehicle are controlled using the wind-over-vehicle envelope, the aircraft-relative-to-vehicle speed, and/or the aircraft-relative-to-vehicle direction.

Abstract: A system and method for navigating a vehicle comprising an image sensor in the absence of global positioning information is disclosed. In one embodiment, the method comprises accepting a user-selected target of an image produced by the imaging sensor, determining a difference between an optic flow due only to motion of the vehicle and the selected target of the image, determining a vehicle guidance command at least in part according to the difference between the optic flow of the selected target due to motion of the vehicle and the selected target of the image, and an estimate of a ground speed of the vehicle Vg, and commanding the vehicle at least in part according to the vehicle guidance command. Another embodiment is evidenced by an apparatus having a processor and a communicatively coupled memory storing processor instructions for performing the foregoing operations.

Abstract: Methods and apparatus to recover rotorcraft are disclosed. A disclosed example apparatus includes a rotor of a vehicle, a rotatable hub to support the rotor, and a rotor hook disposed on the rotor. The rotor hook has a groove to receive a recovery line. The rotor is to contact the recovery line when the vehicle is flown toward the recovery line.

Abstract: Apparatus and methods for controlling an aircraft and/or a vehicle are described. A vehicle speed and direction are received. A wind-over-vehicle speed and direction of wind at the vehicle are measured. An aircraft ground speed and direction are received. An aircraft-relative-to-vehicle speed and an aircraft-relative-to-vehicle direction are calculated based on the aircraft ground speed and direction and the wind-over-vehicle speed and direction. A wind-over-vehicle envelope is calculated based on system design limits for retrieving the aircraft at the vehicle. The wind-over-vehicle envelope maps limits of wind-over-vehicle speeds over a range of directions that enable retrieval of the aircraft at the vehicle. The aircraft and/or the vehicle are controlled using the wind-over-vehicle envelope, the aircraft-relative-to-vehicle speed, and/or the aircraft-relative-to-vehicle direction.

Abstract: A system and method for navigating a vehicle comprising an image sensor in the absence of global positioning information is disclosed. In one embodiment, the method comprises accepting a user-selected target of an image produced by the imaging sensor, determining a difference between an optic flow due only to motion of the vehicle and the selected target of the image, determining a vehicle guidance command at least in part according to the difference between the optic flow of the selected target due to motion of the vehicle and the selected target of the image, and an estimate of a ground speed of the vehicle Vg, and commanding the vehicle at least in part according to the vehicle guidance command. Another embodiment is evidenced by an apparatus having a processor and a communicatively coupled memory storing processor instructions for performing the foregoing operations.

Abstract: A system and method for navigating a vehicle comprising an image sensor in the absence of global positioning information is disclosed. In one embodiment, the method comprises accepting a user-selected target of an image produced by the imaging sensor, determining a difference between an optic flow due only to motion of the vehicle and the selected target of the image, determining a vehicle guidance command at least in part according to the difference between the optic flow of the selected target due to motion of the vehicle and the selected target of the image, and an estimate of a ground speed of the vehicle Vg, and commanding the vehicle at least in part according to the vehicle guidance command. Another embodiment is evidenced by an apparatus having a processor and a communicatively coupled memory storing processor instructions for performing the foregoing operations.

Abstract: An example method of establishing a flight pattern adjacent to a target for an aerial vehicle to follow includes determining a stand-off distance to the target. The stand-off distance indicates a distance from the target at a point along the flight pattern. The example method also includes generating the flight pattern in a form of a conchoidal transformation of a lemniscate based on the stand-off distance.

Abstract: A system and method for navigating a vehicle comprising an image sensor in the absence of global positioning information is disclosed. In one embodiment, the method comprises accepting a user-selected target of an image produced by the imaging sensor, determining a difference between an optic flow due only to motion of the vehicle and the selected target of the image, determining a vehicle guidance command at least in part according to the difference between the optic flow of the selected target due to motion of the vehicle and the selected target of the image, and an estimate of a ground speed of the vehicle Vg, and commanding the vehicle at least in part according to the vehicle guidance command. Another embodiment is evidenced by an apparatus having a processor and a communicatively coupled memory storing processor instructions for performing the foregoing operations.

Abstract: An example method of establishing a flight pattern adjacent to a target for an aerial vehicle to follow includes determining a stand-off distance to the target. The stand-off distance indicates a distance from the target at a point along the flight pattern. The example method also includes generating the flight pattern in a form of a conchoidal transformation of a lemniscate based on the stand-off distance.