Multiple radio transmissions are processed to determine, for each of a number of directions of arrival of the radio transmissions, a most direct direction of arrival, for example, to distinguish a direct path from a reflected path from the target. In some examples, the radio transmissions include multiple frequency components, and channel characteristics at different frequencies are compared to determine the direct path.

A method performed by a first communication device operating in a wireless communications network. The first communication device obtains a set of correspondences associating: i) each set (.sub.i) of a plurality of sets of antenna weights (.sub.1 . . . .sub.i) having been sent by a third communication device in response to having received a respective set (RSs.sub.i) of a plurality of sets of radio signals (RSs.sub.1 . . . RSs.sub.i) from a set of antenna ports in a second communication device, with ii) a respective direction of transmission (d.sub.i) between the second communication device and the third communication device. The respective direction is relative to an orientation (.sub.i) of the second communication device. The respective direction of transmission (d.sub.i) is a selected direction of transmission (d.sub.i,i). The first communication device then initiates transmission of a new radio signal, based on the obtained set of correspondences.

Disclosed are an apparatus and a method for estimating a parameter of a multi path signal. The apparatus for estimating a parameter of a multi path signal includes: a plurality of pre-processing units configured to pre-process respective reception signals received through a plurality of antennas; a plurality of parameter converting units configured to approximate a parameter set of the respective pre-processed reception signals to have a sparse characteristic in a Doppler frequency and angle of arrival domain; and a parameter estimating unit configured to estimate an angle of arrival for a plurality of reception signals in each frequency region of the Doppler frequency and angle of arrival domain.

Various technologies for identifying RF emitters in geolocation datasets are described herein. Doppler signatures of RF emitters and geolocation data of objects in a scene are collected simultaneously, then range-rate profiles of the movement of the RF emitters and the objects in the scene are computed. An RF emitter is identified in a geolocation dataset by comparing the motion of the RF emitter with the motion of an object in the scene as described by the respective range-rate profiles.

Directional characterization of a location of a target device makes use of multiple radio transmissions that are received from the target device. In some examples, each radio transmission is received at a first antenna at a fixed location, and is also received at a second moving antenna. The received transmissions are combined to determine the directional characterization, for example, as a distribution of power as a function of direction. In some examples, the received radio transmissions are processed to determine, for each of a plurality of directions of arrival of the radio transmissions, a most direct direction of arrival, for example, to distinguish a direct path from a reflected path from the target.

Directional characterization of a location of a target device makes use of multiple radio transmissions that are received from the target device. In some examples, each radio transmission is received at a first antenna at a fixed location, and is also received at a second moving antenna. The received transmissions are combined to determine the directional characterization, for example, as a distribution of power as a function of direction. In some examples, the received radio transmissions are processed to determine, for each of a plurality of directions of arrival of the radio transmissions, a most direct direction of arrival, for example, to distinguish a direct path from a reflected path from the target.

A method for determining a yaw direction of a wind turbine includes the following steps, receiving at a component of the wind turbine a signal broadcasted from a source, determining a direction from the component towards the source based on the received signal, determining the yaw direction of the wind turbine in relation to the determined direction towards the source is provided. Further, a wind turbine and a device as well as a computer program product and a computer readable medium are disclosed for performing the method.

A method for determining a yaw direction of a wind turbine includes the following steps, receiving at a component of the wind turbine a signal broadcasted from a source, determining a direction from the component towards the source based on the received signal, determining the yaw direction of the wind turbine in relation to the determined direction towards the source is provided. Further, a wind turbine and a device as well as a computer program product and a computer readable medium are disclosed for performing the method.

A system for estimating an angle of arrival of a signal includes an object, a movable component that is movably coupled to the object, and at least first and second spaced-apart antennas coupled to the movable component. The system also includes a controller that is configured to estimate an angle of arrival of a signal based on a difference between a time the signal arrives at the first antenna and a time the signal arrives at the second antenna while the movable component is moving, and a difference between a frequency of arrival of the signal at the first antenna and a frequency of arrival of the signal at the second antenna while the movable component is moving.

A system is disclosed. The system may include a receiver or transmitter node. The receiver or transmitter node may include a communications interface with an antenna element and a controller. The controller may include one or more processors and have information of own node velocity and own node orientation relative to a common reference frame. The receiver or transmitter node may be time synchronized to apply Doppler corrections to signals, the Doppler corrections associated with the receiver or transmitter node's own motions relative to the common reference frame, the Doppler corrections applied using Doppler null steering along Null directions. The receiver node is configured to determine a bearing angle based on the signals based on Doppler null steering; and to determine a range based on two-way time-of-flight based ranging signals.