In examples, systems and methods for direction finding of electromagnetic signals are described. The device includes a first antenna configured to receive electromagnetic energy. The device also includes a second antenna configured to separately receive the same electromagnetic energy. The device further includes a radome located in a receiving pathway of the first antenna, where the radome is configured to cause a predetermined phase shift that varies based on an angular position of the receiving pathway. The device includes 1 or more radio receivers to receive the signals independently from the antennas. Additionally, the direction finding device includes a processor configured to determine an angle of arrival of the electromagnetic energy based on a comparison of a phase of the electromagnetic energy received by the first antenna to a phase of the electromagnetic energy received by the second antenna.

A method for jointly estimating gain-phase error and direction of arrival (DOA) based on an unmanned aerial vehicle (UAV) array includes: equipping each UAV with an antenna, and forming a receive array through a swarm of multiple UAVs to receive source signals; when an observation baseline of the swarm remains unchanged, changing array manifold through movement of the UAVs, and re-sensing the source signals; for each sensed source signals, calculating a covariance matrix, and obtaining a corresponding noise subspace through eigenvalue decomposition; and constructing a quadratic optimization problem based on the noise subspace and array steering vector, constructing a cost function, and implementing joint estimation of the gain-phase error and the DOA through spectrum peak search. The method can jointly estimate the DOA and gain-phase error and calibrate the gain-phase error, thereby improving accuracy of passive positioning.

An apparatus and method for beam-forming communication in a mobile wireless backhaul network. The apparatus included in a base station includes: an antenna unit radiating a beam according to predetermined beam characteristics and transmitting a signal of the base station to a mobile terminal in a high speed moving body; a position searching unit detecting a distance, a speed, and a direction of movement between the base station and the mobile terminal; a beam setting unit grouping one or more beams according to the detected distance between the base station and the mobile terminal and setting the number of beam search groups in which a beam search is to be performed and a beam search period according to the detected speed and direction of movement; and a beam searching unit searching for the beam of the mobile terminal based on beam setting values set by the beam setting unit.

An apparatus and method for beam-forming communication in a mobile wireless backhaul network. The apparatus included in a base station includes: an antenna unit radiating a beam according to predetermined beam characteristics and transmitting a signal of the base station to a mobile terminal in a high speed moving body; a position searching unit detecting a distance, a speed, and a direction of movement between the base station and the mobile terminal; a beam setting unit grouping one or more beams according to the detected distance between the base station and the mobile terminal and setting the number of beam search groups in which a beam search is to be performed and a beam search period according to the detected speed and direction of movement; and a beam searching unit searching for the beam of the mobile terminal based on beam setting values set by the beam setting unit.

Methods and systems for spatial filtering transmitters and receivers capable of simultaneous communication with one or more receivers and transmitters, respectively, the receivers capable of outputting source directions to humans or devices. The methods and systems use spherical wave field partial wave expansion (PWE) models for transmitted and received fields at antennas and for waves generated by contributing sources. The source PWE models have expansion coefficients expressed as functions of directional coordinates of the sources. For spatial filtering receivers a processor uses the output signals from at least one sensor outputting signals consistent with Nyquist criteria representative of the wave field and the source PWE model to determines directional coordinates of sources (wherein the number of floating point operations are reduced) and outputs the directional coordinates and communications to a reporter configured for reporting information to humans. For spatial filtering transmitters a processor uses known receiver directions and source partial wave expansions to generate signals for transducers producing a composite total wave field conveying communications to the specified receivers. The methods and communications reduce the processing required for transmitting and receiving spatially filtered communications.

Methods and systems for spatial filtering transmitters and receivers capable of simultaneous communication with one or more receivers and transmitters, respectively, the receivers capable of outputting source directions to humans or devices. The methods and systems use spherical wave field partial wave expansion (PWE) models for transmitted and received fields at antennas and for waves generated by contributing sources. The source PWE models have expansion coefficients expressed as functions of directional coordinates of the sources. For spatial filtering receivers a processor uses the output signals from at least one sensor outputting signals consistent with Nyquist criteria representative of the wave field and the source PWE model to determines directional coordinates of sources (wherein the number of floating point operations are reduced) and outputs the directional coordinates and communications to a reporter configured for reporting information to humans. For spatial filtering transmitters a processor uses known receiver directions and source partial wave expansions to generate signals for transducers producing a composite total wave field conveying communications to the specified receivers. The methods and communications reduce the processing required for transmitting and receiving spatially filtered communications.

Various technologies pertaining to computing angle of arrival of radio signals are described. A system that is configured for computing the angle of arrival of a radio signal includes a cylindrical sheath wrapped around a cylindrical object, where the cylindrical sheath acts as a ground plane. The system further includes a plurality of antennas that are positioned about an exterior surface of the cylindrical sheath, and receivers respectively coupled to the antennas. The receivers output measurements pertaining to the radio signal. A processing circuit receives the measurements and computes the angle of arrival of the radio signal based upon the measurements.

Various technologies pertaining to computing angle of arrival of radio signals are described. A system that is configured for computing the angle of arrival of a radio signal includes a cylindrical sheath wrapped around a cylindrical object, where the cylindrical sheath acts as a ground plane. The system further includes a plurality of antennas that are positioned about an exterior surface of the cylindrical sheath, and receivers respectively coupled to the antennas. The receivers output measurements pertaining to the radio signal. A processing circuit receives the measurements and computes the angle of arrival of the radio signal based upon the measurements.

An interferometry system including a first telescope for simultaneously receiving a first optical/infrared signal and a first radio signal from a target; a second telescope configured to simultaneously receive a second optical/infrared signal and a second radio signal from the target; a first beam splitter communicatively connected to the first telescope, where the first beam splitter is configured to separate the first optical/infrared signal from the first radio signal; a second beam splitter communicatively connected to the second telescope, where the second beam splitter is configured to separate the second optical/infrared signal from the second radio; and a first optical/infrared interferometer configured to detect an interferometry image of the target using the first and second optical/infrared and radio signals.

An interferometry system including a first telescope for simultaneously receiving a first optical/infrared signal and a first radio signal from a target; a second telescope configured to simultaneously receive a second optical/infrared signal and a second radio signal from the target; a first beam splitter communicatively connected to the first telescope, where the first beam splitter is configured to separate the first optical/infrared signal from the first radio signal; a second beam splitter communicatively connected to the second telescope, where the second beam splitter is configured to separate the second optical/infrared signal from the second radio; and a first optical/infrared interferometer configured to detect an interferometry image of the target using the first and second optical/infrared and radio signals.