Abstract: In one embodiment, a circuit, having a single supply, is provided to transmit a wireless signal with low common mode electromagnetic interference (EMI) emission. The circuit can achieve common mode attenuations of 40 dB or greater as a result of the symmetric built circuit. Also included is a system that includes a transmission circuit and a receiver circuit, and a method of using such a system.

Abstract: A method of selectively addressing one or more transponders in a set (17) of transponders (21, 22, 23, 24, 25) is described. The method comprise transmitting a first set of one or more commands (25; 251, 252) selected to be not executable by a first subset (24; 242) of transponders or to be executable in a shorter time by the first subset of transponders than by a second subset of transponders (23; 231, 232) in the set, and transmitting a second set of one or more commands (26; 253) such that the second set of commands are received by the transponders while the second subset of transponders are still executing the first set of commands.

Abstract: A method and system for modeling and processing vehicular traffic data and information, comprising: (a) transforming a spatial representation of a road network into a network of spatially interdependent and interrelated oriented road sections, for forming an oriented road section network; (b) acquiring a variety of the vehicular traffic data and information associated with the oriented road section network, from a variety of sources; (c) prioritizing, filtering, and controlling, the vehicular traffic data and information acquired from each of the variety of sources; (d) calculating a mean normalized travel time (NTT) value for each oriented road section of said oriented road section network using the prioritized, filtered, and controlled, vehicular traffic data and information associated with each source, for forming a partial current vehicular traffic situation picture associated with each source; (e) fusing the partial current traffic situation picture associated with each source, for generating a single co

Abstract: A gun detection system and method to prevent school and business shootings is provided that is capable of detecting a firearm a significant distance away from the point of entry and triggering response of an alarm and an automatic door locking system.

Abstract: A method for measuring the position of a surface of a vehicle on a roadway comprising the following steps: transmitting and receiving radar beams at transmitting and receiving positions in various primary transmitting and primary receiving directions and converting these beams into received signals; selecting the received signal having the greatest signal strength; and determining the aforementioned position from the transmitting and receiving positions and the primary transmitting and primary receiving directions of the received signal having the greatest signal strength.

Abstract: Systems, apparatuses, and methods are configured to monitor signals received via a transmission medium by a paging monitor to detect an activity trigger. Systems, apparatuses, and methods are further configured to, in response to detecting the activity trigger, cause, by the paging monitor, a main receiver to transition from an energy conservation mode to an active mode to monitor the transmission medium for data traffic.

Abstract: The various technologies presented herein relate to the determination of whether a received signal comprising radar clutter further comprises a communication signal. The communication signal can comprise of a preamble, a data symbol, communication data, etc. A first portion of the radar clutter is analyzed to determine a radar signature of the first portion of the radar clutter. A second portion of the radar clutter can be extracted based on the radar signature of the first portion. Following extraction, any residual signal can be analyzed to retrieve preamble data, etc. The received signal can be based upon a linear frequency modulation (e.g., a chirp modulation) whereby the chirp frequency can be determined and the frequency of transmission of the communication signal can be based accordingly thereon. The duration and/or bandwidth of the communication signal can be a portion of the duration and/or the bandwidth of the radar clutter.

Abstract: A method of orientating a vehicle for a potential impact includes detecting an object proximate a vehicle with at least one sensor mounted to the vehicle, identifying if the object is a pedestrian, determining a potential for a collision between the object and the vehicle with a controller mounted within the vehicle and determining a vehicle orientation for mitigating damage based on the determined potential for collision. The determined vehicle orientation includes at least an independent determination of a ride height for each corner of the vehicle. The method further includes actuating a suspension component to move each corner of the vehicle to the determined ride height for that corner independent of the other corners of the vehicle to place the vehicle in an orientation determined to mitigate damage and injury. A controller provides the independent determination of a ride height for each corner of the vehicle.

Abstract: A method of medium access control (MAC) type detection for a communication device compatible of a plurality of media each conformed to a communication standard in a network system is disclosed. The method comprises generating a library, wherein the library includes at least a character for each medium, configuring a MAC layer of the communication device according to the library, and determining the existence of a medium according to the configuration result.

Abstract: A mobile device determines its location accurately by measuring the range to a position reflector as well as azimuth and elevation angles of arrival (AOA) at the reflector. The mobile can transmit a coded radar signal and process reflections to determine its location. The reflectors may include internal delays that can identify the reflector and provide transmit/receive separation for the mobile. The reflection can include a primary and further delayed secondary reflection. The mobile can determine the internal delay of the reflector based on the delay between primary and secondary reflections. The range and AOA information can be combined with information about the position, orientation, and characteristics of the reflectors to determine location. In some systems, the mobile device can determine its location in a three-dimensional space using reflections from only one reflector. The reflectors, which can be economically produced, can be unpowered and low profile for easy installation.

Abstract: Disclosed herein is an external airbag deployment method. The method includes setting, by a controller, a detection area located in front. In addition, the method includes setting, by the controller, a target object from objects detected in the detection area, when an object has a relative velocity greater than a first reference, an overlap greater than a second reference, and a TTE less than a third reference, wherein TTE is a remaining time until the object collides with an airbag cushion when the external airbag is predicted to be deployed. Furthermore, the method includes determining, by the controller, whether a relative velocity and an overlap, predicted at a time when the target object is predicted to collide with the vehicle, are greater than predetermined levels and deploying the external airbag when the predicted relative velocity and overlap are greater than the predetermined levels.

Abstract: A combination of active reader tags and ultra wideband (UWB) radar systems provide real-time monitoring of first responders, with identification of each team member using active tags, and detection of victims or other subjects using motion or breathing detection, in a field of operations such as a building affected by fire or hazardous material or search and rescue mission area. Initially, a cluster of miniaturized radars (sensors) act in a static mode of operation, gathering static radar information used to depict a constructed layout of the premises. The cluster of radars then operate in a dynamic mode that detects motion or breathing of multiple subjects inside the field of operations. With dual mode operation the system can read the active tags identification, and by triangulation, display the position of each first responder with its identification and positions of subjects on a composite image of the constructed layout.

Abstract: A primary side wireless power transmitter inductively couplable to a secondary side wireless power receiver for receiving communications from the secondary side wireless power receiver through the inductive coupling having a primary side tank circuit receiving a signal from the secondary side wireless power receiver. A phase delay or time delay circuit generates a fixed delay clock signal from a signal utilized to excite the primary side tank circuit. A sample and hold circuit samples a tank circuit voltage utilizing the fixed phase or time delayed clock signal. A comparator is coupled to an output of the sample and hold circuit for extracting data or commands from the signal stream. A method of operating a primary side wireless transmitter inductively coupled to a secondary side wireless power receiver for supplying power to the wireless power receiver to power a load coupled to the receiver is also disclosed.

Abstract: A primary side wireless power transmitter inductively couplable to a secondary side wireless power receiver for supplying power to the wireless power receiver for receiving communications from the secondary side wireless power receiver through the inductive coupling comprises a primary side tank circuit receiving a signal on from the secondary side wireless power receiver. A phase delay or time delay circuit generates a fixed delay clock signal. A sample and hold circuit samples a tank circuit voltage utilizing the fixed phase or time delayed clock signal. A comparator is coupled to an output of the sample and hold circuit for extracting data or commands from the signal stream. A method of operating a primary side wireless transmitter inductively coupled to a secondary side wireless power receiver for supplying power to the wireless power receiver to power a load coupled to the receiver is also disclosed.

Abstract: Methods, apparatuses and systems for radio frequency identification (RFID)-enabled information collection are disclosed, including an enclosure, a collector coupled to the enclosure, an interrogator, a processor, and one or more RFID field sensors, each having an individual identification, disposed within the enclosure. In operation, the interrogator transmits an incident signal to the collector, causing the collector to generate an electromagnetic field within the enclosure. The electromagnetic field is affected by one or more influences. RFID sensors respond to the electromagnetic field by transmitting reflected signals containing the individual identifications of the responding RFID sensors to the interrogator. The interrogator receives the reflected signals, measures one or more returned signal strength indications (“RSSI”) of the reflected signals and sends the RSSI measurements and identification of the responding RFID sensors to the processor to determine one or more facts about the influences.

Abstract: An article having a conductive body, a magnetic diverter, and a communication device is described. The magnetic diverter is positioned on an outer surface of the conductive body. The magnetic diverter covers a substantial portion of the outer surface of the conductive body. A communication device is positioned on the outer surface of the diverter or may be recessed therein. The communication device is capable of signal coupling with a reader.

Abstract: System, methods and apparatus are described that facilitate transmission of data over a multi-wire data communications link, particularly between two devices within an electronic apparatus. Each symbol in a sequence of symbols received from a plurality of signal wires is received in an odd transmission interval or an even transmission interval. A first clock signal is generated from transitions in signaling state of the wires occurring between each odd transmission interval and a consecutive even transmission interval. A second clock signal is generated from transitions in signaling state of the plurality of wires occurring between each even transmission interval and a consecutive odd transmission interval. The first and second clock signals are used to capture symbols received in even and odd transmission intervals, respectively.

Abstract: Methods for identifying a vehicle using a predetermined location are provided, as well as a radio beacon and an onboard unit for use with the methods. One method comprises: carrying, on the vehicle, an onboard unit that broadcasts status messages that each indicate a current position of the onboard unit and a radio identifier that changes after each or several status messages; receiving at least one status message in a radio beacon; detecting a location usage of the vehicle by evaluating the status message(s) based on the position(s) indicated therein with respect to the predetermined location; transmitting an identification request from the radio beacon to the onboard unit addressed according to the radio identifier from the status message(s); receiving and conducting a legitimacy check of the identification request in the onboard unit and, if the request is legitimate, transmitting an identification of the onboard unit to the radio beacon.

Abstract: According to one embodiment of the present invention, a method for determining the location of a subject is provided.

Abstract: An RFID tag is configured to adjust its current clock frequency to conserve tag power while receiving a reader signal and/or backscattering a signal. The tag may determine whether to adjust its current clock frequency based on one or more timing parameters, which may be determined from a reader command and/or from a signal to be backscattered. The counting rate and/or limit of a tag counter and/or the power supplied to a tag component may also be adjusted. The current tag clock frequency may be adjusted during the signal reception/backscattering process and optionally restored once the process is completed.

Abstract: Wireless data communication is implemented using respective carrier frequencies. As may be implemented in accordance with one or more embodiments and apparatuses herein, wireless communications are effected using a resonant circuit having a resonant frequency susceptible to detuning. Radio frequency power is transmitted to a remote transponder circuit, and wireless communications are effected with the remote transponder circuit via at least one of first and second different carrier frequencies, using the resonant circuit and the radio frequency power. The first and second carrier frequencies are respectively sufficiently proximate to the resonant frequency, such that signals communicated based on the resonant frequency can be acquired by demodulating based on the resonant frequency. One of the first and second carrier frequencies is selected based upon a signal sent from the transponder circuit.

Abstract: A locator loop control system includes a guideway configured to define a travel path of a vehicle. The locator loop control system further includes a locator loop located along the guideway, the locator loop configured to exchange information with a vital on-board controller (VOBC) on-board the vehicle. The locator loop control system further includes a first proximity plate located along the guideway, the first proximity plate spaced a first distance along the guideway from the locator loop, and a wayside controller configured to communicate with the locator loop.

Abstract: Methods for identifying a vehicle using a predetermined location, and a radio beacon and an onboard unit are provided. One method comprises: carrying, on the vehicle, an onboard unit that broadcasts status messages that each indicate a current relative distance of the onboard unit from the predetermined location and a radio identifier that changes after each or several status messages; receiving at least one status message in a radio beacon; detecting a location usage of the vehicle by evaluating the status message(s) based on the indicated relative distance; transmitting an identification request from the radio beacon to the onboard unit addressed according to the radio identifier from the status message(s); receiving and conducting a legitimacy check of the identification request in the onboard unit; and if the request is legitimate, transmitting an identification of the onboard unit to the radio beacon that remains the same over changes of radio identifier.

Abstract: A NFC communicator or NFC communications enabled device has a data store to store data, a coupler to couple inductively with the magnetic field of a radio frequency signal and a signal generator to supply a radio frequency signal to the coupler. A modulator is provided to modulate a radio frequency signal in accordance with data and a demodulator is provided to extract data from a modulated radio frequency signal inductively coupled to the coupler. A controller enables the NFC communicator or NFC communications enabled device both to initiate near field radio frequency communication with another near field RF communicator and to respond to near field radio frequency communication initiated by another near field RF communicator. The NFC communicator or NFC communications enabled device also has a power deriver that derives power from a radio frequency signal inductively coupled to the coupler to charge a chargeable power supply.

Abstract: A tag decides a response based on a plurality of queries received from a reader, determines whether to transmit the response, transmits the response to the reader according to the results of the determination, and transmits a message authentication code including communication content to the reader. The reader calculates a consumed time period which is the time difference between a transmission time at which the queries are transmitted and a reception time at which the response is received, calculates an average consumed time period of the consumed time period, and measures a distance to the tag based on the average consumed time period. Accordingly, it is possible to check an attacker's intervention with a high probability, thereby improving distance measurement performance. Also, the tag may efficiently perform computing and communication.

Abstract: A system, method and computer program product according to one embodiment are provided for calibrating an RFID interrogator. A signal is sent from an interrogator to a calibration device. A backscatter signal is received from the calibration device. The backscatter from the calibration device is analyzed. An outgoing signal strength of the interrogator is adjusted based on the analysis. In a system, method and computer program product according to another embodiment, the interrogator is set to selectively respond to tags returning a backscatter signal strength selected based on the analysis. In a system, method and computer program product according to another embodiment, comparison criteria is selected based on the analysis of the backscatter signal. An RF device is instructed to store the comparison criteria, which is then used by the RF device to selectively respond to an interrogator signal having at least a desired strength.

Abstract: A transmission-guard is disclosed for preventing an inductive power outlet from transmitting power in the absence of an inductive power receiver. A transmission lock is associated with an inductive power outlet and a transmission key is associated with an inductive power receiver. The transmission lock is configured to prevent a primary inductor from connecting to the power supply unless triggered by a release signal via the transmission key.

Abstract: An electronic device with RFID circuitry is provided. The electronic device is operative to instruct the RFID circuitry to provide a desired message indicative of an event associated with the electronic device. For example, if the electronic device experienced some type of system failure, the device may instruct the RFID circuitry to provide a message indicative of that failure.

Abstract: An RFID tag is configured to adjust its current clock frequency to conserve tag power while receiving a reader signal and/or backscattering a signal. The tag may determine whether to adjust its current clock frequency based on one or more timing parameters, which may be determined from a reader command and/or from a signal to be backscattered. The counting rate and/or limit of a tag counter and/or the power supplied to a tag component may also be adjusted. The current tag clock frequency may be adjusted during the signal reception/backscattering process and optionally restored once the process is completed.

Abstract: A transmission-guard is disclosed for preventing an inductive power outlet from transmitting power in the absence of an inductive power receiver. A transmission lock is associated with an inductive power outlet and a transmission key is associated with an inductive power receiver. The transmission lock is configured to prevent a primary inductor from connecting to the power supply unless triggered by a release signal via the transmission key.

Abstract: A method for detecting a message provided with a preamble with a number of pulses in a signal sent by an interrogator or a transponder in mode S, said method including a step for decomposition of said signal into an amplitude signal and into a complex phase signal, a step for detection of said preamble by correlating the amplitude signal with a replica signal of the expected pulses, and a phase control step executed by adding together the samples of the phase signal for the duration of the pulses of said preamble and by comparing the sum obtained with a threshold. The method may include a step for time synchronization by correlation of the complex phase signal with a reference sequence formed by one or more known bits before the decoding of the data. The method applies notably to the decoding of interrogation messages borne by low-power signals.

Abstract: Systems and methods for providing antenna calibration can be used in a variety of applications. A method of calibrating an antenna array for use in a traffic advisory system or traffic alert and collision avoidance system provide a mechanism that renders complex combining circuitry unnecessary in the array. A method can include receiving an unsolicited reply that contains absolute position information of an intruder aircraft. The method can also include determining a bearing of a signal encoding the reply based on a phase relationship of the signals from an antenna array not configured to operate with an internal self-test phase calibration mechanism. The method can further include comparing the bearing based on the phase relationship with a bearing calculated by a comparison of the absolute positions of a host aircraft and the intruder aircraft. The method can additionally include calibrating the antenna array based on the result of the comparison.

Abstract: An embodiment of the present invention relates to a radar apparatus, wherein a distance to a target and a velocity of the target are measured by transmitting a digitally modulated transmitting signal using a digital code and receiving and demodulating an echo signal returned due to reflection of the transmitting signal from the target.

Abstract: In the embodiments described herein, a RFID enabled license plate is constructed by using the license plate, or a retro-reflective layer formed thereon as part of the resonator configured to transmit signals generated by and RFID chip integrated with the license plate. Such an RFID enabled license plate can include a metal license plate with a slot formed in the metal license plate, and a RFID tag module positioned in the slot. The RFID tag module can include a chip and a loop, and the loop can be coupled with the metal license plate, e.g., via inductive or conductive coupling. In this manner, the metal license plate can be configured to act as a resonator providing increased performance.

Abstract: Arrangement and method for monitoring a material storage container which includes a housing defining an interior receivable of removable material. An interior sensor system is arranged on the housing to obtain information about any material in the interior of the housing different than the location of the container. A location determining system is arranged on the housing to monitor the location of the container, and a communication system is coupled to the interior sensor system and the location determining system and transmits information about the material in the housing and the location of the container to one or more remote facilities. The communication system may be arranged on the housing itself, which is especially applicable when the housing is movable, for example, such as the housing of a Frac tank. The location and condition of the material in the container can thus be known at all times.

Abstract: This invention relates to a method for determining at least one of a distance and a relative velocity by means of continuous wave radar measurements. The method includes generating a measurement signal in the form of a continuous wave radar signal; transmitting the measurement signal by means of an antenna (112); reflecting the measurement signal by means of a reflector (118), thereby providing a desired reflected measurement signal; receiving the desired reflected measurement signal; and determining at least one of a distance and a relative velocity between the antenna and the reflector by means of the desired reflected measurement signal. The reflection of the measurement signal involves asymmetrically modulating the measurement signal at the reflector. The determination of at least one of a distance and a relative velocity includes detecting the desired reflected measurement signal among several received reflections of the measurement signal, by means of information added by the asymmetric modulation.

Abstract: A radar system is provided. The system includes a radar transceiving device equipped in a movable body and for transmitting an electromagnetic wave at a first frequency, and a transponder device arranged in a beacon and for transmitting a response wave upon receiving the electromagnetic wave. The transponder device includes a response wave transmitting module for transmitting, when a radar classification of the radar transceiving device is a solid-state radar, a response wave at a second frequency different from the first frequency in response to receiving the transmitted electromagnetic wave. The radar transceiving device includes a transmitting module for transmitting the electromagnetic wave, a receiving module for receiving a radar echo at the first frequency and the response wave at the second frequency, and a display controlling module for displaying, on a predetermined radar display unit, locations of the beacon and another movable body existing around the movable body.

Abstract: A system (234, 220, 200) for monitoring movements of one or more users and/or one or more projectiles during sports activities performed by the one or more users is provided. The one or more projectiles (200) incorporate sensors (202, 204) for sensing movements of the one or more projectiles (200) during the sports activities. A user interface (220) is used for presenting automated sports training services. A data processing arrangement (234, 232, 220) is used for analysing one or more records of the movements of the one or more projectiles (200) against reference data, for providing the automated sports training services to the one or more users via the user interface (220).

Abstract: A method for interleaving time slots in a multi-antenna system for communication with RFID tags is disclosed. An example is shown for an eight antenna system. A first four antennas arranged side-by-side are sequentially energized to interrogate RFID transponders. A second set of four antennas arranged side-by-side, the first of which is adjacent to the last of the first set of antennas. A four-antenna sequence is performed for the first four antennas and a second four antenna sequence is performed for the second set of antennas. The first and second four antenna sequences are offset by only a marginal amount, sufficient to ensure that a transponder signal received four antennas away from an active antenna is not acknowledged because the receive window for the non-active antenna is delayed.

Abstract: A bend sensor for use in wirelessly sensing an amount of bend of a joint or other monitored object. The sensor includes a radio frequency (RF) antenna and an integrated circuit linked to the antenna. The integrated circuit or chip is passive and responds to, or is powered by, a read signal received by the antenna to transmit a reflected signal via the antenna such as to an RFID reader. The sensor also includes a transducer linked to the integrated circuit. The transducer defines reflecting impedance, which modulates amplitude and phase of the reflected signal. The transducer has impedance varying with deformation or bend. In one example, the transducer includes an upper conductor, and the amount of the deformation is defined by a bend radius of the upper conductor. The read signal may be at 5 GHz or higher such with the antenna and the transducer being microwave structures.

Abstract: An RFD reader includes a transceiver configured to receive a first radio frequency signal reflected off at least one surface to provide baseline signal information and a second radio frequency signal reflected off the at least one surface and an object to provide further signal information. A comparator is configured to compare the baseline signal information and the further signal information to provide a signal comparison. A processor is configured to detect the presence of the object in accordance with the signal comparison. A determination is made whether the object is in motion in accordance with the signal comparison. The determination whether the object is in motion is made in accordance with a continuous fluctuation of the second radio frequency signal. A determination whether the object is no longer in motion is made in accordance with an ending of the continuous fluctuation of the second radio frequency signal.

Abstract: A system and method for a single site beacon transceiver including an omni-directional transceiver, a plurality of directional receiving antennas for receiving a signal, and a digital receiver for processing the signal to determine an azimuth to the source of the received signal. The digital receiver includes a plurality of receiver channels that are calibrated periodically and at least one processor that estimates a coarse signal azimuth for the signal by calculating an amplitude monopulse ratio for the signal using the two directional receiving antennas receiving the highest amplitude signal, and estimates a final signal azimuth for the signal using an interferometer baseline between the two directional receiving antennas or, alternately, subtracts the complex ratio of the measurements from the complex ratio of the antenna array RF model to determine the angle corresponding to the minimum of the absolute value of the difference.

Abstract: A method for the real-time management and sequencing of the information interchanges between a secondary radar and a plurality of aircraft includes the interchanges between the radar and a given aircraft being performed, depending on the aircraft concerned, either in a non-selective, SSR, IFF or “All Call” interrogation mode or in a selective “Roll Call” interrogation mode. According to this method, the information interchanges according to the non-selective interrogation modes are performed during successive periods specifically allocated to these modes, whereas each transaction forming an information interchange in selective mode between the radar and a given aircraft is temporally inserted into the time slots not used in periods by the interrogation-response tasks in non-selective mode. The method applies equally to the secondary radars exclusively dedicated to civilian air traffic control and to the secondary radars dedicated to combined civilian and military aircraft control tasks.

Abstract: Systems and methods to use radar systems for radio frequency identification (RFID) applications. In one embodiment, radar systems are adapted to use RFID communications protocols and methods to enhance the usefulness of radar systems beyond the determination of the presence, distance, direction and/or speed of a vehicle or object, to additionally include the transmission of data such as object identification and additional messages or data.

Abstract: Radio Frequency Identification (RFID) readers may transmit one or more run commands specifying one or more programs for tag execution prior to tag singulation. A run command may encapsulate the program(s), in which case a tag may store or store and execute the program(s). A run command may alternatively specify programs stored on a tag. The reader may instruct a tag to execute the program(s) upon receipt, upon a trigger event, serially or in parallel, and/or may cause the tag to modify the program(s) by adjusting parameters. The reader may instruct tags to execute the program(s) via the run command or another command, which may be sent prior to tag singulation. A reader may cause a tag to determine whether to participate in a subsequent inventory round, modify a behavior during a subsequent inventory round, or store a result in a tag memory, based on the executed program(s).

Abstract: In an example implementation, an autonomous vehicle is configured to detect closures and lane shifts in a lane of travel. The vehicle is configured to operate in an autonomous mode and determine a presence of an obstacle substantially positioned in a lane of travel of the vehicle using a sensor. The lane of travel has a first side, a second side, and a center, and the obstacle is substantially positioned on the first side. The autonomous vehicle includes a computer system. The computer system determines a lateral distance between the obstacle and the center, compares the lateral distance to a pre-determined threshold, and provides instructions to control the autonomous vehicle based on the comparison.

Abstract: A distance separation tracking process is provided that includes the transmission of a periodic radio frequency original signal from a beacon transceiver. The original periodic signal from the beacon transceiver is received at a remote target transceiver as a target received periodic signal. The target retransmits the received periodic signal to the beacon transceiver as a return periodic signal. Data points of the return periodic signal are sampled and used to calculate a phase differential between the original periodic signal and the return periodic signal that correlates to the distance separation range between the beacon transceiver and the target transceiver.

Abstract: A method and system for reading RFID tags in a high-density environment using a directional scanning antenna system is provided. The directional scanning antenna system consists of transmit and receive antennas having highly directional antenna patterns which work together to read and locate the tags. In operation both types of antennas are stepped in a circular fashion with respect to each other wherein the transmit antenna's antenna pattern pauses during rotation while the receive antenna pattern sweeps across the radiating antenna's path produced by the transmit antenna such that the antenna patterns produced from each isolate and determine the location of the tags.

Abstract: A system for measuring the range to an RFID tag including situations containing high clutter and multi-path signals is disclosed. The system includes an RFID reader; an RFID tag; and a coordinated pulse compression radar system. In the system the RFID reader causes the tag to respond to received signals in a first backscatter state at a first time and a second backscatter state at a second time. The pulse compression radar system transmits short pulses coordinated by the backscatter state of the RFID tag and the system creates a differential signal comprised of the differences between radar signals obtained during the first and second states of the tag to obtain an uncorrupted measure of a round trip time of flight of said radar pulses between the pulse radar system and the RFID tag.

Abstract: Communication between a remote locator and a transponder is used to determine the relative position of the transponder. The transponder and locator each include a transmitter and a receiver. The locator transmits an inquiry in the form of a relatively powerful cyclically encoded signal with repetitive elements, uniquely associated with a target transponder. Periodically, each transponder correlates its coded ID against a possible inquiry signal, determining frequency, phase and framing in the process. Upon a match, the transponder transmits a synthesized response coherent with the received signal. The locator integrates multiple cyclical response elements, allowing low-power transmissions from the transponder. The locator correlates the integrated response, determines round-trip Doppler shift, time-of-flight, and then computes the distance and angle to the transponder. The transponder can be wearable, bionically implanted, or attached to, or embedded in, some object.