An electronic patient monitoring system and method of operation that includes one or more generally non-metal, tamper-resistant patient identification and monitoring devices, an observer transmitter/receiver device configured to receive and detect one or more beacon signals that exceed a predetermined threshold from at least one of the not easily removable patient identification and monitoring devices, set a time to hold open a window for a response on the transmitter/receiver device, and send a request for information to the observer with the transmitter/receiver device, and a central computer system. Each of the transmitter/receiver device and the central computer system, including, at least, a computer processor, communications components and system software to communicate with the observer transmitter/receiver device at specified/predetermined time intervals to receive observer- and patient-specific information.

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.

Systems and methods track a first object when continuous tracking information for the first object is not available. The systems and methods detect when the tracking information for the first object is not available. A last time of a last determined location of the first object is determined and a second object closest to the last determined location at the last time is determined. The location of the first object is associated with a location of the second object if tracking information for the first object is not available.

An interrogator and system employing the same. In one embodiment, the interrogator includes a receiver configured to receive a return signal from a tag and a sensing module configured to provide a time associated with the return signal. The interrogator also includes a processor configured to employ synthetic aperture radar processing on the return signal in accordance with the time to locate a position of the tag.

A transponder, able to equip a cooperative target facing a Doppler radar, includes at least one receiving antenna able to receive a signal transmitted by said radar and a transmitting antenna able to retransmit a signal. The signal received by the receiving antenna is amplitude-modulated before being retransmitted by the transmitting antenna to produce a variation of the radar cross-section of the target, the variation triggering a frequency shift between the signal transmitted and the signal received by the radar comparable to a Doppler echo. The transponder applies notably to the field of radars, more particularly for collaborative systems also operating at low velocity or nil velocity. It applies for example to assisted take-off, landing and deck-landing of drones, in particular rotary-wing drones, as well as manned helicopters.

The present invention relates to systems, methods, and devices for consumers using RFID-tagged items for multichannel shopping using smartphones, tablets, and indoor navigation, preservation of consumer's privacy related to RFID-tagged items that they leave a retail store with, and automatically reading and locating retail inventory without directly using store labor. Robots and aerial mobile automated RFID reading devices are disclosed.

An identification or messaging system is provided that has embodiments including a embodiment with a structure with different faces and a base with reflective or resonance panels which are positioned at different receiving angles to detect direct signals and amplify them including in a sequence to be detected by an active emitter that emits electromagnetic radiation that is reflected and steered or resonated off or with the panels. An emitter can be an aerial platform with the emitter and a library of reflected or resonated signals that are associated with a particular sequence of panels on the structure which are associated with a particular entity identification or message. Thermal patterned and/or magnetic patterned panels (e.g., for backplane beamforming) and return signal steering can also be provided. Embodiments with secondary signaling systems can also be provided. A variety of various embodiments and methods are also provided.

A tracking system comprising: a transmitter configured to steer an RF beam across a detection range, a passive RFID tag configured to be enabled for locating substantially when located in the center of the RF beam of the transmitter, and an RFID reader configured to detect the tag 104 once enable.

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.

An OFDM radar sensor system having a plurality of transmitting and receiving units. One of the transmitting and receiving units is an OFDM radar sensor, and another of the transmitting and receiving units is a repeater which is configured to modulate a signal generated and transmitted by the OFDM radar sensor and received by the repeater into a signal orthogonal to the signal received by the repeater and to emit the modulated signal. The OFDM radar sensor is configured to separate a portion of a signal received by the OFDM radar sensor, which portion corresponds to the modulated signal, from a monostatic portion of the signal received by the OFDM radar sensor.