Multi-rotors use multiple electric motors to drive propellers that allow the multi-rotor to fly, turn, bank, etc. The multiple motors and the associated control device produce EM signals that can be used to detect multi-rotors and distinguish them from other devices with electric motors. To drive a brushless motor, the ESC takes DC from the battery and turns it into three phase AC (sinusoidal or trapezoidal wave), and then measures back EMF pulses (sensorless). This allows one to ensure that the three phase AC is being generated at the proper frequency to turn the motor (timing). For each propeller in the multi-rotor there are usually four different correlated signals at multiple frequencies that are used for detection and false alarm rejection.

Disclosed are examples of systems, apparatus, methods and computer program products for locating unmanned aerial vehicles (UAVs). A region of airspace may be scanned with two scanning apparatuses. Each scanning apparatus may include one or more directional Radio Frequency (RF) antennae. The two scanning apparatuses may have different locations. Radio frequency signals emitted by a UAV can be received at each of the two scanning apparatuses. The received radio frequency signals can be processed to determine a first location of the UAV.

Systems and methods for tracking a target depression angle relative to a reference location. In accordance with some embodiments, the system comprises a set of algorithms and pilot displays that use data from an onboard navigation system to calculate an asset's location relative to a reference location, allowing for precise control of relative geometry for the purposes of system measurement and performance assessment. The system provides a pilot with tracking error and steering cues along a flight profile, allowing for closed-loop tracking of target depression angle (body axis elevation) while sweeping look angle (body axis azimuth) relative to a static or dynamic reference location.

Systems and methods for tracking a target depression angle relative to a reference location. In accordance with some embodiments, the system comprises a set of algorithms and pilot displays that use data from an onboard navigation system to calculate an asset's location relative to a reference location, allowing for precise control of relative geometry for the purposes of system measurement and performance assessment. The system provides a pilot with tracking error and steering cues along a flight profile, allowing for closed-loop tracking of target depression angle (body axis elevation) while sweeping look angle (body axis azimuth) relative to a static or dynamic reference location.

A radio wave arrival direction estimation device according to an embodiment includes an antenna angle acquisition unit that acquires each of antenna angles indicating a plurality of different directions in which antennas having non-uniform antenna patterns are sequentially directed, a reception intensity measurement unit that measures reception intensities at which the antenna has received a radio wave at each of the antenna angles acquired by the antenna angle acquisition unit, a matching degree Calculation unit that calculates a matching degree between the antenna angle acquired by the antenna angle acquisition unit and the reception intensity measured by the reception intensity measurement unit, and an antenna pattern of the antenna for each antenna angle acquired by the antenna angle acquisition unit, and an estimation unit that estimates an antenna angle at which the matching degree Calculated by the matching degree Calculation unit is the maximum as an arrival direction of the radio wave.

A radio wave arrival direction estimation device according to an embodiment includes an antenna angle acquisition unit that acquires each of antenna angles indicating a plurality of different directions in which antennas having non-uniform antenna patterns are sequentially directed, a reception intensity measurement unit that measures reception intensities at which the antenna has received a radio wave at each of the antenna angles acquired by the antenna angle acquisition unit, a matching degree Calculation unit that calculates a matching degree between the antenna angle acquired by the antenna angle acquisition unit and the reception intensity measured by the reception intensity measurement unit, and an antenna pattern of the antenna for each antenna angle acquired by the antenna angle acquisition unit, and an estimation unit that estimates an antenna angle at which the matching degree Calculated by the matching degree Calculation unit is the maximum as an arrival direction of the radio wave.

Disclosed are examples of systems, apparatus, methods and computer program products for locating unmanned aerial vehicles (UAVs). A region of airspace may be scanned with two scanning apparatuses. Each scanning apparatus may include one or more directional Radio Frequency (RF) antennae. The two scanning apparatuses may have different locations. Radio frequency signals emitted by a UAV can be received at each of the two scanning apparatuses. The received radio frequency signals can be processed to determine a first location of the UAV.

Certain aspects of the present disclosure provide methods and apparatus for enhancing a beamforming training procedure.

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may include a processing system configured to generate a frame including a data field and a plurality of training subfields. The data field may include information indicating a different direction for transmitting each of the training subfields. The apparatus may include an interface configured to output the frame for transmission with the data field in a first direction and the training subfields in their respective directions.

Disclosed are examples of systems, apparatus, methods and computer program products for locating unmanned aerial vehicles (UAVs). A region of airspace may be scanned with two scanning apparatuses. Each scanning apparatus may include one or more directional Radio Frequency (RF) antennae. The two scanning apparatuses may have different locations. Radio frequency signals emitted by a UAV can be received at each of the two scanning apparatuses. The received radio frequency signals can be processed to determine a first location of the UAV.