A system to maintain a phase difference is disclosed. Two or more aircraft fly in a continuous periodic trajectory. The system maintains a phase difference between the two or more aircraft. Telemetry information for a reference aircraft moving in a first periodic trajectory is received. A phase difference between a primary aircraft and the reference aircraft with respect to the first periodic trajectory is determined. A variance in the phase difference between the primary aircraft and the reference aircraft from the target phase difference is determined. A new trajectory for the primary aircraft that decreases the variance in the phase difference with respect to the new periodic trajectory is determined, and the primary aircraft is maneuvered to follow the new trajectory.

To reduce environmental influence in flight (including taking-off and landing) of a flying object, main drone current position information acquisition unit acquires a current position of a main drone from a main drone control terminal, and provides the current position to the movement instruction unit. The sub-drone current position information acquisition unit acquires a current position from the sub-drone, and provides it to the movement instruction unit. The movement instruction unit determines a movement position of the sub-drone on the basis of the current position of the main drone. In addition, the movement instruction unit generates a movement instruction for the sub-drone based on a difference between the current position and the movement position of the sub-drone, and transmits the movement instruction to the sub-drone. The drive control unit acquires the movement instruction transmitted from the sub-drone control terminal.

A system to maintain a phase difference is disclosed. Two or more aircraft fly in a continuous periodic trajectory. The system maintains a phase difference between the two or more aircraft. Telemetry information for a reference aircraft moving in a first periodic trajectory is received. A phase difference between a primary aircraft and the reference aircraft with respect to the first periodic trajectory is determined. A variance in the phase difference between the primary aircraft and the reference aircraft from the target phase difference is determined. A new trajectory for the primary aircraft that decreases the variance in the phase difference with respect to the new periodic trajectory is determined, and the primary aircraft is maneuvered to follow the new trajectory.

Systems and methods are disclosed for determining a vehicle elevation height for launching an unmanned aerial vehicle. Example methods may include performing a quantitative balancing analysis using baseline factors, establishing optimal values for operational goals of a vehicle based on the quantitative balancing analysis, determining a vehicle elevation height that achieves the established optimal values for the operational goals of the vehicle by evaluating vehicle delivery parameters using normalized values, and initiating on a winch system elevation of the unmanned aerial vehicle to the determined vehicle elevation height for launching.

Embodiments are disclosed for a machine and process that include a computer code specially programmed for creating a runway extension speed for an aircraft taking off. The process may include sensing current location, current acceleration, and current speed, for the aircraft during takeoff roll; receiving, in a ROTTOWIRE, the current speed and the current acceleration for the aircraft; creating in the ROTTOWIRE an actual speed profile; creating, using a specially coded program in the ROTTOWIRE and the current acceleration, the runway extension speed via determining, for a current location of the aircraft, a distance from a departure end of the runway and a terminating distance required to terminate the takeoff to a stop of the aircraft on the runway, a distance until the aircraft reaches a designated height; and when the terminating distance equals the distance from the departure end of the runway; and presenting the runway extension speed.

An unmanned aerial vehicle control method and apparatus are provided. The method includes: obtaining, in real time, the motion status information of an unmanned aerial vehicle moving under the effect of a user-applied external force (100); generating at least one unmanned aerial vehicle control instruction based on the motion status information (110) and controlling the unmanned aerial vehicle to perform a corresponding flight action according to the at least one unmanned aerial vehicle control instruction (120). After an unmanned aerial vehicle moves under the effect of a user-applied external force, the control method further controls the unmanned aerial vehicle to perform a corresponding flight action according to the current motion tendency of the unmanned aerial vehicle, thus freeing the user from mastering a complicated unmanned aerial vehicle control technology, reducing the difficulty of the control over the unmanned aerial vehicle and making the unmanned aerial vehicle more applicable.

A system to maintain a phase difference is disclosed. Two or more aircraft fly in a continuous periodic trajectory. The system maintains a phase difference between the two or more aircraft. Telemetry information for a reference aircraft moving in a first periodic trajectory is received. A phase difference between a primary aircraft and the reference aircraft with respect to the first periodic trajectory is determined. A variance in the phase difference between the primary aircraft and the reference aircraft from the target phase difference is determined. A new trajectory for the primary aircraft that decreases the variance in the phase difference with respect to the new periodic trajectory is determined, and the primary aircraft is maneuvered to follow the new trajectory.

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.

Wind speed and direction experienced by the UAV at altitude is determined by placing an accelerometer, gyroscope and compass on the UAV. A change in velocity experienced by the UAV is determined by the accelerometer. An orientation relative to a reference plane and an angular velocity experienced by the UAV is determined by the gyroscope. A magnetic bearing of the UAV is determined with the compass. A roll and pitch exhibited by the UAV is determined as a function of the change in velocity, orientation and change in angular velocity. Projected roll and projected pitch vectors onto a horizontal plane cutting through the center of rotation of the UAV are determined as a function of the roll and the pitch. The wind speed of the wind experienced by the UAV is determined as a function of the projected roll vector and projected pitch vector. The wind direction is determined as a function of the projected roll vector and projected pitch vector and the magnetic bearing of the UAV.

Embodiments include apparatus and methods for modeling air flow from flight responses in aerial vehicles. Sensor data is received for aerial vehicles in a geographic area. The pose (e.g., roll, pitch, and yaw) of the aerial vehicles is calculated from the sensor data. One or more wind vectors are calculated based, at least in part, on the pose. An air flow model is generated from the wind vectors.