A system and method are provided for detecting direction of movement. The system includes at least two radio frequency identification (RFID) readers arranged in different locations. The RFID readers transmit respective location signals from their locations and receive corresponding response signals from a portable electronic device (PED) when the PED is within range to receive the corresponding location signals, respectively. The system includes a controller configured to determine whether the individual response signals received by the RFID readers respectively satisfy a predetermined condition at a first time and a second time subsequent to the first time. The controller is also configured to determine a direction of movement of the portable electronic device relative to the locations of the RFID readers during the first and second times based on whether the response signals respectively satisfy the predetermined condition at the first and second times.

An RFID tag reading system and method accurately and rapidly determine true bearings of RFID tags associated with items in a controlled area. An RFID reader has an array of antenna elements and a plurality of RF transceivers. A controller controls the transceivers by steering a primary transmit beam over the controlled area to each tag, by steering a primary receive beam at a primary steering angle from each tag, by steering a plurality of secondary receive beams at different secondary steering angles that are offset from the primary steering angle by receiving secondary receive signals from each tag, and by processing the secondary receive signals to determine a true bearing for each tag. Bidirectional communication between the reader and a tag is conducted over a single inventory round in which the tag is read a plurality of times by the primary and the secondary receive beams.

An RFID tag reading system and method accurately and rapidly determine true bearings of RFID tags associated with items in a controlled area. An RFID reader has an array of antenna elements and a plurality of RF transceivers. A controller controls the transceivers by steering a primary transmit beam over the controlled area to each tag, by steering a primary receive beam at a primary steering angle from each tag, by steering a plurality of secondary receive beams at different secondary steering angles that are offset from the primary steering angle by receiving secondary receive signals from each tag, and by processing the secondary receive signals to determine a true bearing for each tag. Bidirectional communication between the reader and a tag is conducted over a single inventory round in which the tag is read a plurality of times by the primary and the secondary receive beams.

An apparatus includes a pavement marker configured to be mounted to a road at a lane line of a lane at known orientation with respect to the lane line; and an RF device carried by the raised pavement marker. The RF device is configured to transmit a directional RF navigation signal and it is positioned relative to the known orientation to transmit the signal across the lane in a direction that is substantially normal to the lane line.

Apparatus and methods are provided for using a retroflected target for calibrating environmental geometric sensing systems. In particular, apparatus and methods are provided for unstructured calibrations using a plurality of spatial sensing data acquisitions and the data correlations thereof. In various implementations, a combined LiDAR-RADAR detector is used to associate one with the other. According to one aspect of the present disclosure, a predetermined LiDAR detector is used as a reference frame for RADAR segmentation. Specifically, a LiDAR point-of-interest is conveyed to RADAR system for unstructured calibration. To that end, RADAR and LiDAR can be calibrated with one another without the need for absolute positioning.

Apparatus and methods are provided for using a retroflected target for calibrating environmental geometric sensing systems. In particular, apparatus and methods are provided for unstructured calibrations using a plurality of spatial sensing data acquisitions and the data correlations thereof. In various implementations, a combined LiDAR-RADAR detector is used to associate one with the other. According to one aspect of the present disclosure, a predetermined LiDAR detector is used as a reference frame for RADAR segmentation. Specifically, a LiDAR point-of-interest is conveyed to RADAR system for unstructured calibration. To that end, RADAR and LiDAR can be calibrated with one another without the need for absolute positioning.

At least some embodiments of the present invention are directed to RFID reader systems configured to estimate a directional bearing of an RFID tag. In an embodiment, the present invention is an RFID system configured in a way that upon a detection of a variance in the direction of a maximum RSSI value for a given RFID tag in response to a plurality of interrogation signals transmitted by an RFID reader over a respective plurality of different directions, the RFID reader retransmits the plurality of interrogation signals over the respective plurality of different directions with successively lower power levels until the only response(s) being received no longer exhibit the previously detected variance.

At least some embodiments of the present invention are directed to RFID reader systems configured to estimate a directional bearing of an RFID tag. In an embodiment, the present invention is an RFID system configured in a way that upon a detection of a variance in the direction of a maximum RSSI value for a given RFID tag in response to a plurality of interrogation signals transmitted by an RFID reader over a respective plurality of different directions, the RFID reader retransmits the plurality of interrogation signals over the respective plurality of different directions with successively lower power levels until the only response(s) being received no longer exhibit the previously detected variance.

Disclosed herein are systems, methods and/or computer programs for backscatter localization of a tag using access point (AP) mode switching. The apparatus, may comprise means for: receiving distance information associated with at least two APs from a set of at least three APs. The distance information associated with each AP of the at least two APs may be determined based on: dynamically switching the role of said each AP in a different time interval to a transmission mode for transmitting a localization signal to a tag, with the other APs in the set of APs switched to a receiving mode for receiving a backscatter signal from the tag in response to the transmitted localization signal from said each AP. Distance information determined, by the other APs, may be associated with said each AP based on the received backscatter signals corresponding to the transmitted localization signal from said each AP. There may also be provided means for determining a location estimate of the tag based on the received distance information.

Disclosed herein are systems, methods and/or computer programs for backscatter localization of a tag using access point (AP) mode switching. The apparatus, may comprise means for: receiving distance information associated with at least two APs from a set of at least three APs. The distance information associated with each AP of the at least two APs may be determined based on: dynamically switching the role of said each AP in a different time interval to a transmission mode for transmitting a localization signal to a tag, with the other APs in the set of APs switched to a receiving mode for receiving a backscatter signal from the tag in response to the transmitted localization signal from said each AP. Distance information determined, by the other APs, may be associated with said each AP based on the received backscatter signals corresponding to the transmitted localization signal from said each AP. There may also be provided means for determining a location estimate of the tag based on the received distance information.