A method for determining an arrival-time of a rotor blade that includes attaching an RF reader to a stationary surface and an RF tag to the rotor blade. Time-of-flight data points are collected via an RF monitoring process that includes: emitting an RF signal from the RF reader and recording a first time; receiving the RF signal at the RF tag and emitting a return RF signal by the RF tag in response thereto; receiving the return RF signal at the RF reader and recording a second time; and determining the time-of-flight data point as being the duration occurring between the first time and the second time. The RF monitoring process is repeated until multiple time-of-flight data points are collected. A minimum time-of-flight is determined from the multiple time-of-flight data points, and the arrival-time for the rotor blade is determined as being a time that corresponds to the minimum time-of-flight.

Disclosed are techniques for receiving reference radio frequency (RF) signals for positioning estimation. In an aspect, a user equipment (UE) receives, from a network node, multiple resource sets for tracking (TRSs). Each TRS comprises a plurality of reference signal resources. The multiple TRSs are signals from a same antenna port or are quasi-co-located signals. The UE processes the multiple TRSs to determine positioning-related quantity(ies). The UE can estimate its position based on the positioning-related quantity(ies) and/or send the positioning-related quantity(ies) to the network.

In one implementation, a pair of messages are received from one or more space-based receivers that each received the pair of messages. The pair of messages comprise encoded position information of a transmitter, and a plurality of candidate locations for the transmitter is determined therefrom. A location of the transmitter is determined by eliminating candidate locations until only one remains. In particular, each candidate location that is not within a coverage area of each of the space-based receivers is eliminated, and each candidate location that is not within a predetermined distance of at least one previous candidate location is eliminated. In addition, it is determined that the remaining candidate location is within the coverage area of each of the space-based receivers as well as within the predetermined distance of at least one previous candidate location. Upon determining the location of the transmitter, it is transmitted to a subscriber system.

There is provided a method for determining passage of a portable wireless transceiver device along a constrained path. The method comprises acquiring at least one time of flight (ToF) measurement and auxiliary information, the at least one ToF measurement being measured between a portable wireless transceiver device and a single network node. The network node is mounted proximate a constrained path. The method comprises determining whether the portable wireless transceiver device has passed the network node along the constrained path or not based on the at least one ToF measurement and the auxiliary information.

Systems, methods, and apparatuses for determining the distance between two positions are disclosed. The system includes a correlator, a first receiver, and a second receiver. The first and second receivers each include: an antenna, a steering mechanism, and a processor. The steering mechanism steers the antenna in an azimuthal direction and an elevation direction. The processor is configured to (i) control the steering mechanism, (ii) receive data recorded by the antenna from a plurality of sources, (iii) time-stamp the data recorded by the antenna, and (iv) control the transmission of the time-stamped data to the correlator. The correlator is configured to receive the time-stamped recorded data from the first receiver and the second receiver, and calculate a distance between the first receiver and the second receiver based thereon.

A technique for detecting a velocity state of a device includes generating multiple phase measurements for each of multiple packets emitted by the device and monitoring differences between phase measurements made for different packets. The technique further includes asserting a particular velocity state of the device based on a condition of the monitored differences.

A technique for measuring yaw (left-right direction) of a device includes obtaining a first measurement of an orientation of the device relative to a local magnetic frame of reference (FoR) and a second measurement of the orientation of the device relative to a spatial FoR, with both measurements made while the device is disposed at a known location and in the same orientation. The technique further includes computing an offset between the two measurements and storing the offset in connection with the known location. When the device later returns to the same location, the yaw direction of the device is determined based on acquiring a new measurement of the device's orientation relative to the local magnetic FoR and applying the offset as a correction.

A system and method for locating radio-frequency identification tags within a predetermined area. The method can incorporate sub-threshold superposition response mapping techniques, alone, or in combination with other methods for locating radio-frequency identification tags such as but not limited to time differential on arrival (TDOA), frequency domain phase difference on arrival (FD-PDOA), and radio signal strength indication (RSSI). The system can include a plurality of antennas dispersed in a predefined area; one or more radio-frequency identification tags; a radio-frequency transceiver in communication with said antennas; a phase modulator coupled to the ra-dio-frequency transceiver; and a system controller in communication with said transceiver and said phase modulator. Calibration techniques can be employed to map con-structive interference zones for improved accuracy.

In one implementation, a pair of messages are received from one or more space-based receivers that each received the pair of messages. The pair of messages comprise encoded position information of a transmitter, and a plurality of candidate locations for the transmitter is determined therefrom. A location of the transmitter is determined by eliminating candidate locations until only one remains. In particular, each candidate location that is not within a coverage area of each of the space-based receivers is eliminated, and each candidate location that is not within a predetermined distance of at least one previous candidate location is eliminated. In addition, it is determined that the remaining candidate location is within the coverage area of each of the space-based receivers as well as within the predetermined distance of at least one previous candidate location. Upon determining the location of the transmitter, it is transmitted to a subscriber system.

A system and method for locating radio-frequency identification tags within a predetermined area. The method can incorporate sub-threshold superposition response mapping techniques, alone, or in combination with other methods for locating radio-frequency identification tags such as but not limited to time differential on arrival (TDOA), frequency domain phase difference on arrival (FD-PDOA), and radio signal strength indication (RSSI). The system can include a plurality of antennas dispersed in a predefined area; one or more radio-frequency identification tags; a radio-frequency transceiver in communication with said antennas; a phase modulator coupled to the ra-dio-frequency transceiver; and a system controller in communication with said transceiver and said phase modulator. Calibration techniques can be employed to map con-structive interference zones for improved accuracy.