A sensor includes a reception antenna, a parasitic antenna terminating in a variable load, a controller, a transmitter transmitting a transmission signal, a receiver, a memory, and a processor. The controller sets an impedance value of the variable load. The receiver receives a first signal formed of signals received by the antennas and derived from the transmission signal, and the signal received by the parasitic antenna corresponding to the impedance value. The memory stores a first signal strength value of the first signal corresponding to the impedance value. The processor sets candidates of a complex propagation channel, calculates second signal strength values of a second signal respectively corresponding to the candidates, estimates a target complex propagation channel by selecting a candidate corresponding to a minimum difference among differences between the first signal strength value and the second signal strength values, and estimates a direction of arrival of the first signal.

A sensor includes a reception antenna, a parasitic antenna terminating in a variable load, a controller, a transmitter transmitting a transmission signal, a receiver, a memory, and a processor. The controller sets an impedance value of the variable load. The receiver receives a first signal formed of signals received by the antennas and derived from the transmission signal, and the signal received by the parasitic antenna corresponding to the impedance value. The memory stores a first signal strength value of the first signal corresponding to the impedance value. The processor sets candidates of a complex propagation channel, calculates second signal strength values of a second signal respectively corresponding to the candidates, estimates a target complex propagation channel by selecting a candidate corresponding to a minimum difference among differences between the first signal strength value and the second signal strength values, and estimates a direction of arrival of the first signal.

Techniques are provided for jammer detection. A methodology implementing the techniques according to an embodiment includes estimating an angle of arrival of a jamming signal, the jamming signal included in a received signal, and generating a direction finding (DF) confidence indicator associated with the estimated angle of arrival. The method also includes extracting the jamming signal from the received signal. The method further includes correlating the extracted jamming signal with previously extracted jamming signals to generate a correlation score and using the correlation score as a uniqueness assessment of the extracted jamming signal. The method further includes identifying characteristics of the extracted jamming signal and generating a characterization confidence indicator. The method further includes demoting the extracted jamming signal to non-jammer status based on one or more of the DF confidence indicator, the uniqueness assessment, and the characterization confidence indicator.

The various embodiments herein provide a Uniform Circular Displaced Sensor Array (UC-DSA) system and method for measuring/estimating Direction of Arrival (DOA) of a wireless signal. The UC-DSA system comprises at least a set of two circular antenna arrays. The two circular antenna arrays have a number of elements. A Radio frequency (RF) receiver captures a wireless signal incident on a circular antenna array. A Direction of Arrival (DOA) estimator processes a received input signal and a Triangulation system provides the exact location of the source of the wireless signal. The two circular antenna arrays with the same number of elements are placed on different radii, and are shifted to have equal separation between inner elements and outer elements.

The various embodiments herein provide a Uniform Circular Displaced Sensor Array (UC-DSA) system and method for measuring/estimating Direction of Arrival (DOA) of a wireless signal. The UC-DSA system comprises at least a set of two circular antenna arrays. The two circular antenna arrays have a number of elements. A Radio frequency (RF) receiver captures a wireless signal incident on a circular antenna array. A Direction of Arrival (DOA) estimator processes a received input signal and a Triangulation system provides the exact location of the source of the wireless signal. The two circular antenna arrays with the same number of elements are placed on different radii, and are shifted to have equal separation between inner elements and outer elements.

A system includes a phased array antenna that is used to emulate antennas that have larger solid angle coverage and lower gain compared to a single beam of the phased array antenna. This is achieved by switching between beams of the phased array antenna while receiving a wireless communication signal and summing representations of signal energy received using the different beams. The system can be used to narrow down the angular coordinates of a transmitting satellite by emulating antenna patterns that cover portions of a search space. The system can also be used to determine a channel discriminator (e.g., frequency, code, time slot) that defines a signal being transmitted.

A system includes a phased array antenna that is used to emulate antennas that have larger solid angle coverage and lower gain compared to a single beam of the phased array antenna. This is achieved by switching between beams of the phased array antenna while receiving a wireless communication signal and summing representations of signal energy received using the different beams. The system can be used to narrow down the angular coordinates of a transmitting satellite by emulating antenna patterns that cover portions of a search space. The system can also be used to determine a channel discriminator (e.g., frequency, code, time slot) that defines a signal being transmitted.

In receiving radio waves from a transmitter by an array antenna, and estimating an arrival direction of a direct wave, delay times of the arriving waves are estimated (13) by means of a super-resolution process based on transmission channel estimation results, an arriving wave component corresponding to the delay time having been determined to be equal to or longer than a threshold value is removed (15) from the transmission channel estimation results, arriving wave components after the removal are separated from each other to extract direct wave components (17), and an arrival angle is estimated (19). The arrival direction of the direct wave can be accurately estimated in an environment where delayed waves of short delay times are present. Also, the amount of calculation is small even when the super-resolution process is performed.

The invention provides an indoor positioning method and system based on a wireless receiver and a camera, belonging to the field of positioning technology. The method in the invention comprises the following steps: a wireless receiver detects a query WIFI signal transmitted by a target device and extracts a MAC address and CSI of the target device from a query WIFI signal; a server captures the MAC address and the CSI of the target device from the wireless receiver, calculates an incident angle of the target device and the wireless receiver and sends a photographing instruction to a camera which photographs an image and uploads the image to the server; the server obtains the distance between the wireless receiver and the target device through the image pixels, and calculates the position information of the target device according to the coordinates of the wireless receiver. The invention realizes the accurate positioning of the target device by using only a wireless receiver and a camera, so that the cost can be controlled and a real-time calculation can be ensured; the combination of the two beneficial effects can help achieve good positioning results.

A system and method to resolve angle of arrival (AOA) ambiguity in a radar system include receiving received reflections at a plurality of transceiver nodes. Each transceiver node among the plurality of transceiver nodes of the radar system receives one or more of the received reflections at respective one or more receive elements. The method includes determining candidate AOAs {circumflex over (?)}.sub.i based on phases differences in the received reflections at the plurality of transceiver nodes, and determining Doppler frequencies f.sub.d.sup.i based on the received reflections. An estimated AOA {circumflex over (?)} is selected from among the candidate AOAs {circumflex over (?)}.sub.i based on matching metrics ?.sub.i between the Doppler frequencies and the candidate AOAs {circumflex over (?)}.sub.i.