A positioning method includes: emitting an interrogator signal from an electronic device; detecting, by the electronic device, a response signal that is generated and emitted by a sensor among a plurality of sensors, in response to the interrogator signal; and acquire location information about the sensor by identifying the sensor based on the detected response signal. The response signal is generated based on transduction of the interrogator signal.

A method for locating devices that transmit, backscatter or receive a wireless signal. The method comprising using each of one or more backscatter devices to modulate and backscatter a carrier signal transmitted by a transmitter. Modulating and backscattering the carrier signal generates a backscattered modulated signal comprising a sideband. The method further comprises receiving the one or more backscattered modulated signals with a receiver. At least one of the phase or amplitude of each sideband are used to determine at least one of: the distance between the transmitter and the backscatter device by which that sideband was generated, the distance between the receiver and the backscatter device by which that sideband was generated, and the sum thereof.

A method and apparatus for determining the position of a RFID tag. The method includes the following: (1) measuring the position of an active device to an accuracy of better than 1.0 meter using a radio locating system to determine the position of a reference point; (2) detecting a first RF signal from a reference RFID tag near the reference point with an RF receiver in an RFID reading system; (3) detecting a second RF signal from a RFID tag of interest with the RF receiver in the RFID reading system; and (4) processing both the first RF signal and the second RF signal and relying upon at least partially the position of the reference point to determine the position of the RFID tag of interest.

A method and apparatus for determining the position of a RFID tag. The method includes the following: (1) measuring the position of an active device to an accuracy of better than 1.0 meter using a radio locating system to determine the position of a reference point; (2) detecting a first RF signal from a reference RFID tag near the reference point with an RF receiver in an RFID reading system; (3) detecting a second RF signal from a RFID tag of interest with the RF receiver in the RFID reading system; and (4) processing both the first RF signal and the second RF signal and relying upon at least partially the position of the reference point to determine the position of the RFID tag of interest.

A vehicle access system includes an identification device with a first transceiver, a short-range transceiver and a processor configured to control the first transceiver and the short-range transceiver to activate the first transceiver only when a distance measurement between the identification device and a vehicle is within a predefined range as determined utilizing the short-range transceiver.

A system and method is disclosed for measuring time of flight to an object. A transmitter transmits an electromagnetic signal and provides a reference signal corresponding to the electromagnetic signal. A receiver receives the electromagnetic signal and provides a response signal corresponding to the received electromagnetic signal. A detection circuit is configured to determine a time of flight between the transmitter and the receiver based upon the reference signal and the response signal.

A system and method is disclosed for measuring time of flight to an object. A transmitter transmits an electromagnetic signal and provides a reference signal corresponding to the electromagnetic signal. A receiver receives the electromagnetic signal and provides a response signal corresponding to the received electromagnetic signal. A detection circuit is configured to determine a time of flight between the transmitter and the receiver based upon the reference signal and the response signal.

The invention relates to a radar method for exchanging signals between at least two non-coherent transceiver units which respectively have initially non-synchronous, in particular controllable, clock sources, having the following steps: a synchronization in which clock offsets and/or clock rates of the clock sources of the at least two transceiver units are adapted; a full-duplex measuring process in which a first transmission signal of the first transceiver unit is transmitted to the second transceiver unit and a second transmission signal of the second transceiver unit is transmitted to the first transceiver unit via a radio channel; with synchronization prior to the full-duplex measuring process being carried out in such a way that a time offset and/or a frequency offset between the transmission signals at least substantially remain(s) constant during a transmission time of the full-duplex measuring process.

Accuracy for detecting and tracking one or more objects of interest can be improved using radar-based tracking systems. In some examples, multiple radars implemented in a device can be used to transmit signals to, and receive signals from, the one or more objects of interest. To disambiguate an object of interest from undesired objects such as the hand of a user, the object of interest can include a transponder that applies a delay element to a signal received from a radar, and thereafter transmits a delayed return signal back to the radar. The delay produced by the delay element can separate the return signal from undesired reflections and enable disambiguation of those signals. Clear identification of the desired return signal can lead to more accurate object distance determinations, more accurate triangulation, and improved position detection and tracking accuracy.

A localization method for locating a target that is coupled with a locator transponder associated with a permanent identification code permanently assigned to the locator transponder is provided. The localization method includes: a) transmitting a spread spectrum paging signal carrying the permanent identification code and a shorter temporary identification code temporarily assigned to the locator transponder; b) receiving the spread spectrum paging signal and extracting the temporary identification code carried by the received spread spectrum paging signal; c) transmitting radar signals towards area(s) of earth's surface or sky and receiving echo signals therefrom; d) upon reception by the locator transponder of radar signal(s), generating and transmitting a sequence of watermarked radar echo signals in which a spread spectrum watermarking signal is embedded that includes the temporary identification code; e) carrying out localization operations; f) transmitting frequency-synchronization-aid signal(s); g) receiving the frequency-synchronization-aid signal(s) and estimating a frequency drift affecting a reference frequency provided by a local oscillator of the locator transponder; wherein the locator transponder transmits the sequence of watermarked radar echo signals by using a transmission carrier frequency obtained based on the reference frequency provided by the local oscillator and on the estimated frequency drift.