Method for localizing a wireless node in a wireless sensor network, and wireless node using the method. The method includes sending a chirp spread spectrum signal with a carrier frequency from a first wireless node (A) to a second wireless node (B), the second wireless node (B) including a plurality of antennas; receiving the chirp spread spectrum signal at the plurality of antennas; executing time-of-arrival ranging between the first and second wireless nodes (A, B) for determining a distance between the first and second wireless nodes (A, B); and detecting a relative phase shift of the received chirp spread spectrum signal at each of the plurality of antennas of the second wireless node (B) and determining a direction of the first wireless sensor node (A) with respect to the second wireless sensor node (B) from the detected relative phase shift.

It is presented a method for determining whether a portable key device is located in an active area in relation to a barrier. The method is performed in an access control device and comprising the steps of: detecting a first angle of arrival of a wireless signal from the portable key device using a first pair of separated antennas; detecting a second angle of arrival of a wireless signal from the portable key device using a second pair of separated antennas; determining a first pair of directions based on the first angle of arrival; determining a second pair of directions based on the second angle of arrival; determining a position of the portable key device to be where one of the first pair of directions intersects one of the second pair of directions; and determining whether the portable key device is located in the active area based on the position.

The invention relates to a method for determining the position of a first sensor node relative to a second sensor node, wherein the first and the second sensor nodes are communicatively connected to each other and are a constituent part of a sensor network, comprising the method steps: reception of signal sections of transmitted signals from at least two transmitters by the first and the second sensor node, beginning at a time t.sub.1 for a time period t.sub.RX; determining the angle of incidence of the transmitted signals to at least one of the sensor nodes; determining the distance between the sensor nodes from the propagation time differences of the transmitted signals from the at least two transmitters received at the first and second sensor nodes; determining the position of the first sensor node relative to the second sensor node from the distance between the sensor nodes and the angle of incidence of the transmitted signals, wherein the sensor nodes determine the time t.sub.1 and the time period t.sub.1 in relation to a reference frequency which is derived from the received transmitted signal from at least one of the transmitters.

The invention relates to a method for determining the position of a first sensor node relative to a second sensor node, wherein the first and the second sensor nodes are communicatively connected to each other and are a constituent part of a sensor network, comprising the method steps: reception of signal sections of transmitted signals from at least two transmitters by the first and the second sensor node, beginning at a time t.sub.1 for a time period t.sub.RX; determining the angle of incidence of the transmitted signals to at least one of the sensor nodes; determining the distance between the sensor nodes from the propagation time differences of the transmitted signals from the at least two transmitters received at the first and second sensor nodes; determining the position of the first sensor node relative to the second sensor node from the distance between the sensor nodes and the angle of incidence of the transmitted signals, wherein the sensor nodes determine the time t.sub.1 and the time period t.sub.1 in relation to a reference frequency which is derived from the received transmitted signal from at least one of the transmitters.

The present invention relates to a method for locating sources emitting electromagnetic pulses, each source belonging to a carrier platform, the method comprising the following steps: receiving, by a detector, for each source to be located, at least one same emitted pulse, received directly and received by reflection on the carrier platform of another source, measuring the arrival direction, the arrival date and at least one invariant characteristic of each received pulse.

The method further comprises the following steps: grouping together a first pair of pulses and a second pair of pulses, calculating the difference of dates of arrival between the pulses of each pair, determining the direction and the distance of each source from the detector from calculated differences of dates of arrival of the pulses of each pair.

This invention relates to methods and systems for localization. It is particularly concerned with localization techniques based on time difference of arrival for wireless devices. Embodiments of the invention relate to techniques in which a transmitter transmits periodic distinguishable signals which are relayed upon receipt by the client whose location is sought in a form distinguishable from that of the transmitter. Signals from both the transmitter and the client are received by at least three signal receivers which generate a time difference of arrival based on the difference taken for a signal to reach the receiver directly and via the client. Further embodiments of the invention provide a phase detector in the receivers to determine the time difference of arrival between the signals.

This invention relates to methods and systems for localization. It is particularly concerned with localization techniques based on time difference of arrival for wireless devices. Embodiments of the invention relate to techniques in which a transmitter transmits periodic distinguishable signals which are relayed upon receipt by the client whose location is sought in a form distinguishable from that of the transmitter. Signals from both the transmitter and the client are received by at least three signal receivers which generate a time difference of arrival based on the difference taken for a signal to reach the receiver directly and via the client. Further embodiments of the invention provide a phase detector in the receivers to determine the time difference of arrival between the signals.

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.

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.