Certain embodiments are directed to techniques (e.g., a device, a method, a memory or non-transitory computer readable medium storing code or instructions executable by one or more processors) for passive beacon communication techniques. Transmitting devices (e.g., beacons) can transmit advertising messages using a first wireless protocol to provide timing for ranging messages for one of more ranging messages over a second protocol (e.g., UWB). One or more receiving devices can determine using signal strength if the devices are within a threshold range to perform communication techniques. Various ranging communications techniques can be used to determine a range between the receiving device and transmitting device. Other techniques can be used to passively calculate the angle of arrival for transmitter signals. The angle of arrival information can be used for precise position locating for the receiving device or to indicate interest in information provided by the one or more transmitting devices.

The present invention provides a low-cost and low-volume mode A/C/S transponder positioning system to detect the position of a target aircraft, or intruder, outside the range of a secondary surveillance radar system. The system uses a signal of the intruder to pinpoint the location of the intruder. The system can be used on both the ground and on an aircraft in a full 360 degree range around the system.

An apparatus for estimating an angle of arrival, comprises: a window setting unit for setting a window time that is a time interval for comparing a template signal and each of a plurality of reception signals obtained by receiving a transmission signal transmitted a pre-designated number of times ; a template generator that generates a template signal of a waveform corresponding to the transmission signal, by adjusting a generation time point in units of the window time; a plurality of signal correlators provided corresponding to each of the plurality of antennas, and detecting a level of a correlation signal obtained by correlating a corresponding reception signal; and an angle of arrival determination unit, determining a reception time at which each of the plurality of reception signals is received by a corresponding antenna, and estimating the angle of arrival of the transmission signal using a difference between the determined reception times.

An apparatus for estimating an angle of arrival, comprises: a window setting unit for setting a window time that is a time interval for comparing a template signal and each of a plurality of reception signals obtained by receiving a transmission signal transmitted a pre-designated number of times ; a template generator that generates a template signal of a waveform corresponding to the transmission signal, by adjusting a generation time point in units of the window time; a plurality of signal correlators provided corresponding to each of the plurality of antennas, and detecting a level of a correlation signal obtained by correlating a corresponding reception signal; and an angle of arrival determination unit, determining a reception time at which each of the plurality of reception signals is received by a corresponding antenna, and estimating the angle of arrival of the transmission signal using a difference between the determined reception times.

Using captured and stored wideband historical radio frequency data bearing information to the source of a signal of interest achieved using as few as two receivers and a plurality of commutating antennas. Wideband IQ data streams are received at two or more receivers and stored for later analysis. A first receiver is coupled to a reference antenna and a second receiver is commutatively coupled to a plurality of commutating antennas. Later, streams of wideband IQ data are retrieved for a select period of time and synchronized. From these streams a signal of interest identified and synchronously sampled over an acquisition interval by each receiver. Phase differences of the signal at each of the plurality commutating antennas is measured enabling a determination of the bearing to the common signal of interest.

According to an aspect, a method of determining two dimensional (2D) angle of arrival (AoA) in a radar system comprising determining one dimensional (1D) AoA to generate a first set of (AoA), selecting a set of valid 1D AoA angles from the first set AoA, and determining the 2D AoA from the set of valid 1D AoA, Wherein the 1D AoA is determined on a first set of data received over a first uniform linear antenna array arranged in the first axis and the 2D AoA is determined on a second set data received over the first and the second MIMO antenna array arranged in the second axis and the set of valid 1D AoA in the first axis. Wherein the second antenna array need not be orthogonal to the first linear antenna array.

According to an aspect, a method of determining two dimensional (2D) angle of arrival (AoA) in a radar system comprising determining one dimensional (1D) AoA to generate a first set of (AoA), selecting a set of valid 1D AoA angles from the first set AoA, and determining the 2D AoA from the set of valid 1D AoA, Wherein the 1D AoA is determined on a first set of data received over a first uniform linear antenna array arranged in the first axis and the 2D AoA is determined on a second set data received over the first and the second MIMO antenna array arranged in the second axis and the set of valid 1D AoA in the first axis. Wherein the second antenna array need not be orthogonal to the first linear antenna array.

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.

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 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.