One inventive aspect is a receiver circuit. The receiver circuit includes a controller selecting a receiver antenna array and/or a transmit antenna array. The controller also calculates a first AoA and/or a first AoD based on signals from the selected receiver and/or transmit antenna array. The controller also, in response to the absolute value of the first AoA minus π/2 not being less than or equal to the AoA threshold angle, selects a different receiver antenna array, and calculates a second AoA based on digitized samples of RF signals from the selected different receiver antenna array. The controller also, in response to the absolute value of the first AoD minus π/2 not being less than or equal to the AoD threshold angle, selects a different transmit antenna array, and calculates a second AoD based on digitized samples of RF signals from the selected different transmit antenna array.

Disclosed is a high-resolution accurate two-dimensional direction-of-arrival estimation method based on coarray tensor spatial spectrum searching with coprime planar array, which solves the problem of multi-dimensional signal loss and limited spatial spectrum resolution and accuracy in existing methods. The implementation steps are: constructing a coprime planar array; tensor signal modeling for the coprime planar array; deriving coarray statistics based on coprime planar array cross-correlation tensor; constructing the equivalent signals of a virtual uniform array; deriving a spatially smoothed fourth-order auto-correlation coarray tensor; realizing signal and noise subspace classification through coarray tensor feature extraction; performing high-resolution accurate two-dimensional direction-of-arrival estimation based on coarray tensor spatial spectrum searching. In the present method, multi-dimensional feature extraction based on coarray tensor statistics for coprime planar array is used to implement high-resolution, accurate two-dimensional direction-of-arrival estimation based on tensor spatial spectrum searching, and the method can be used for passive detection and target positioning.

A receiver circuit is disclosed. The receiver circuit includes a receiver antenna or a receiver antenna arrays oriented at a receiver orientation angle and configured to receive a plurality of RF signals transmitted from a transmitter circuit including a transmit antenna or a transmit antenna array oriented at a transmitter orientation angle. A controller A) calculates first and second AoAs based on a first signal at a first receiver antenna array, and calculates third and fourth AoAs based on a second signal at a second receiver antenna array, and/or B) calculates first and second AoDs based on a third signal from a first transmit antenna array, and calculates third and fourth AoDs based on a fourth signal from a second transmit antenna array. The controller also determines which of the first and second AoAs is correct, and/or determines which of the first and second AoDs is correct.

The present disclosure provides a dual mode antenna, comprising: a first conductive piece; and a second conductive piece, configured to electromagnetically couple with the first conductive piece through a dielectric at a second frequency to operate as a loop antenna with the first conductive piece and configured to operate independently of the first conductive piece at a first frequency to operate as a monopole antenna. The dual mode antenna can be included in an antenna array as one of a plurality of dual mode antennas coupled to a routing substrate or a reference dual mode antenna coupled to the routing substrate along with a plurality of single mode antennas coupled to the routing substrate; wherein each antenna of the plurality of dual mode antennas, the reference dual mode antenna, and the plurality of single mode antennas is arranged evenly relative to a first neighboring antenna and a second neighboring antenna.

A method for radio direction finding using a direction finding system having an antenna, a magnetic field sensor and a control unit, the method comprising: receiving a radio frequency signal of at least one emitter via the antenna by the control unit obtaining a received signal; receiving a magnetic measurement value of the magnetic field at the direction finding system via the magnetic field sensor; correcting the magnetic measurement value obtaining a corrected magnetic measurement value; correcting the received signal obtaining a corrected signal; and determining the precise bearing of the emitter based on the corrected received signal and the corrected magnetic measurement value. Further, a direction finding system and a platform are disclosed.

A receiver circuit is disclosed. The receiver circuit includes one or more receiver antennas configured to receive a plurality of RF signals transmitted from a transmitter circuit including one or more transmit antennas, an RF chain configured to generate a plurality of digitized samples of the received RF signals, and a controller configured to receive the digitized samples, to calculate a plurality of additional samples, and to calculate a measured angle of arrival or angle of departure (AoA or AoD) of the RF signals based on the digitized samples and the calculated additional samples.

A system and method for determining an Angle of Arrival (AOA) for frequency modulated communications. The system may include first and second antennas spaced apart from each other by a distance, and configured to receive wireless communications in the form of a frequency modulated signal. The system may determine a phase difference between the received signals irrespective of the modulations in the signal, thereby facilitating determining an AOA.

A system and method for determining an Angle of Arrival (AOA) for frequency modulated communications. The system may include first and second antennas spaced apart from each other by a distance, and configured to receive wireless communications in the form of a frequency modulated signal. The system may determine a phase difference between the received signals irrespective of the modulations in the signal, thereby facilitating determining an AOA.

Apparatus and systems are disclosed and include a body having a plurality of slots. Each of the plurality of slots includes a first portion, a second portion, and a third portion. The first portion is located on a first surface of the body. The second portion is located on a second surface of the body and forms a helical shape. The third portion is located on a third surface of the body. The first surface and the second surface are non-parallel. The third surface and the second surface are non-parallel. The apparatus includes a plurality of antenna elements that are disposed in a respective one of the plurality of slots. The plurality of antenna elements is configured to receive radio frequency (RF) signals. The apparatus includes a ground plane that is coupled to a first end of each of the plurality of antenna elements.

A system and method are disclosed and include receiving a wireless signal. The method includes generating a first and second set of digital data that are representative of the wireless signal. The method includes obtaining a first and second sample that is representative of a cosine and sine component, respectively, of a pre-known portion of the first set. The method includes obtaining a third and fourth sample that is representative of a cosine and sine component, respectively, of a pre-known portion of the second set. The method includes determining a first phase angle value based on an amplitude of the first and second samples and a second phase angle based on an amplitude of the third and fourth samples. The method includes determining an angle of arrival based on a difference between the first and second phase angle values.