An angle only (AO) target state estimation (TSE) system and method using a mixed coordinate system (Modified Spherical Coordinate (MSC) and Reference Cartesian Coordinate (RCC)) as an integrated system. This integrated system is achieved due to the state vector information of two frames (RCC and MSC) is effectively preserved between processing cycles and state vector transformation steps. The AO TSE architecture and processing schemes are applicable to a wide class of passive sensors. The mixed coordinate system provides robust real-time slant range estimation in a bootstrap fashion, thus turning passive AO measurements into equivalent active sensor measurements with built-in recursive range information but with greatly improved the TSE accuracy meeting the miss distance required by many engagement missions.

The subject matter discloses a casing of a mobile electronic device, comprising: a body, comprising: two or more antennas for exchanging wireless signals with a target device; an electromagnetic absorbing material located between the two or more antennas; electrical circuitry for sending information concerning the wireless signals exchanged between the two or more antennas and the target device to a direction finding module, wherein the direction finding module is operative to determine a relative direction of the target device based on the wireless signals exchanged between the two or more antennas and the target device.

An electronic device may be provided with wireless circuitry that includes first, second, and third antennas used to determine the position and orientation of the electronic device relative to external equipment. The antennas may include patch elements on respective substrates mounted to a flexible printed circuit. Each substrate may include fences of conductive vias that are coupled to ground and that laterally surround the corresponding patch element. Control circuitry may identify phase differences between the first and second antennas and between the second and third antennas and may identify an angle of arrival of received ultra-wideband signals using the phase differences. The control circuitry may compare the phase differences to a set of predetermined surfaces of phase differences to identify environmental loading conditions for the antenna. The control circuitry may correct the angle of arrival using offsets identified based on the environmental loading conditions.

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.

The subject matter discloses a method to determine a relative direction of a target RF transmitter, performed by a direction finding (DF) system comprising at least a pair of antennas having an electromagnetic-absorbing material between them, comprising conducting wireless communication between the target RF transmitter and each one of the antennas of the DF system, measuring the time of flight (TOF) of the target RF transmitter received at each antenna, calculating the difference between the TOFs measured at each one of the antennas in the pair, and determining a relative direction of the target RF transmitter based on the TOF required to reach each of the antennas.

Systems and method for determining an angle of arrival of a radio frequency (RF) signal are disclosed. A radio frequency receiving system as disclosed herein can include a plurality of antenna or receiving elements formed on a common plane. A spacing between the receiving elements can be arbitrary. In response to receiving a radio frequency signal, a difference in an integer number of wavelengths that have passed and a difference in a phase of the received signal is determined between each of a plurality of pairs of antenna elements. More particularly, a residual error is calculated for each possible difference in the number of integer wavelengths that can occur as the received signal travels to the elements in each pair of elements. A solution with a minimum residual value is taken as the difference in the actual integer number of wavelengths that have been traversed by the received signal. That integer value and the detected phase difference is applied to determine the angle of arrival.

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.

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.

Iterative methods for direction of arrival estimation of a signal at a receiver with a plurality of spatially separated sensor elements are described. A quantized estimate of the angle of arrival is obtained from a compressive sensing solution of a set of equations. The estimate is refined in a subsequent iteration by a computed error based a quantized estimate of the direction of arrival in relation to quantization points offset from the quantization points for the first quantized estimate of the angle of arrival. The iterations converge on an estimated direction of arrival.

Systems and methods for automated unmanned aerial vehicle recognition. A multiplicity of receivers captures RF data and transmits the RF data to at least one node device. The at least one node device comprises a signal processing engine, a detection engine, a classification engine, and a direction finding engine. The at least one node device is configured with an artificial intelligence algorithm. The detection engine and classification engine are trained to detect and classify signals from unmanned vehicles and their controllers based on processed data from the signal processing engine. The direction finding engine is operable to provide lines of bearing for detected unmanned vehicles.