Abstract: The present invention provides for reducing power consumption of a positioning system having wireless beacons. A wireless transmitter static beacon is provided, which has a known position, signal strength, and range. A mobile device is positioned within the range of the static beacon and its position is determined based on a signal from the static beacon. Foreign wireless transmitter devices and their locations are detected. The immobility of the foreign devices is evaluated by periodically determining their positions and calculating the frequency with which their positions change, and by determining the devices' types. A subset of the foreign devices that are immobile are selected and amalgamated into the positioning system based on device type and position-changing frequency. The signal strength of the static beacon is reduced, which in turn reduces the range of the static beacon.

Abstract: This invention relates to a target detection device and its detection method, comprising: a transmitting unit for transmitting a detecting pulse to detect target which then reflects the detecting pulse to generate a reflected pulse; a plurality of measuring units, located at different positions respectively which receive said reflected pulse and generates measured values of distance and measured values of velocity according to the reflected pulse received; a plurality of two-stage linear Kalman filters, corresponding to said plural measuring units respectively, each of said plural two-stage linear Kalman filters proceeds an operation according to the measured values produced by corresponding measuring unit so as to generate respectively the estimation values of distance, velocity and acceleration; an arithmetic unit connecting to said plural two-stage linear Kalman filters, which proceeds a triangulation operation according to said estimation values so as to generate distance component values, velocity compon

Abstract: A method and system for predicting a trajectory of an air-to-surface target missile is provided, including detecting a plurality of echo wave signals from the target missile through a plurality of sensors deployed at various locations relative to the target missile, extracting at least one range distance and at least one radial velocity, respectively, from the detected echo wave signals from the sensors by using a hybrid FSK/LFM unit, using a two-stage Kalman filter to filter the computed range distance and radial velocity to obtain a relative distance, a relative velocity and a relative acceleration, respectively, of the target missile, and finally applying trilateration on the relative distance, relative velocity and relative acceleration of the target missile from each two-stage Kalman filter to obtain a location, velocity and acceleration along the x, y, z directions.

Abstract: An intrusion detection system and method are provided that can utilize impulse radio technology to detect when an intruder has entered a protection zone. In addition, the intrusion detection system and method can utilize impulse radio technology to determine a location of the intruder within the protection zone and also track the movement of the intruder within the protection zone. Moreover, the intrusion detection system and method can utilize impulse radio technology to create a specially shaped protection a one before trying to detect when and where the intruder has penetrated and moved within the protection zone.

Abstract: The present invention relates to a system and a method for location determination using time differences. The method of the invention comprises the steps of: transmitting a transmission signal by using a directional transmitter rotating at an angular velocity, the transmission signal comprising a transmission identification and the transmitting time; receiving the transmission signal by using an omnidirectional transceiver, and adding a personal identification to the transmission signal to be a response signal; transmitting the response signal; receiving the response signal by using an omnidirectional receiver and recording the receiving time; and calculating the location of the omnidirectional transceiver corresponding to the directional transmitter according to the difference between the receiving time and the transmitting time.

Abstract: The present invention provides a short-range wireless mobile communication system with a first terminal and a mobile terminal that are each adapted for transmitting and receiving an information carrying signal wave, whereby at least the first terminal or the mobile terminal comprise a directional signal wave converter for transmitting and/or receiving the information carrying signal wave with a directional characteristic and a control means for controlling the directional characteristic according to a position of the mobile terminal relative to the first terminal.

Abstract: A high-frequency position/path sensor for detecting the approach of an object, with a detection range in a near field, which comprises a high-frequency transmitter and a high-frequency receiver, is proposed. The high-frequency transmitter and the high-frequency receiver are arranged and configured such that a main transmitting direction and a main receiving direction lie at an angle to each other.

Abstract: A rescue and safety device for swimming-pools and amusement parks, consisting of a wristband containing a cardiac-arrest detector, a panic button, a location device and, optionally, a water detector, triggered by immersion syncope, cardiac arrest or an accident; a rescue device, especially if an inflatable grid has been installed on the bottom of the pool, that can uplift any person in difficulties from the bottom of the pool.

Abstract: In one embodiment of a positioning system, a transmit element is configured to transmit at least one electromagnetic pulse having a carrier signal frequency. An antenna array with a plurality of receive elements includes at least two receive elements separated by a spacing more than a half wavelength. Each of the at least two receive elements is configured to receive a return signal over a period of time. The return signal includes a return pulse from an object within a detection area of the system. The wavelength corresponds to the carrier signal frequency of the transmitted pulse. A detector is configured to process the return signal from one receive element and the other receive element so as to isolate the return pulse received at each of the at least two receive elements and thereby determine a position of the object in relation to the system.

Abstract: A local positioning system using co-polarized and cross-polarized radar mapping is provided. In one embodiment of the method, at least a first electromagnetic pulse having a first polarization is transmitted. A first return signal preferentially having the first polarization is received over a respective period of time. The first return signal is processed so as to isolate a first return pulse corresponding to an object within a radar detection area of the positioning system. At least a second electromagnetic pulse having the first polarization is also transmitted. A second return signal preferentially having a second polarization is received over a respective period of time. The second return signal is processed so as to isolate a second return pulse corresponding to the object. A characteristic of the object is determined in accordance with a relative signal strength of the first return pulse and the second return pulse.

Abstract: A system and method for determining position of, for example, a robot based on reflected signals comprises a transmitter for transmitting signals in a number of directions within a range of directions and a receiver for receiving echoes of the signals from any direction in the range. The transmitter has a first rotatable antenna and the receiver has a second rotatable antenna which is mechanically couplable to the second antenna. The received echoes are processed by a processor to derive echo data signals indicative of the distance of the system to one or more reflective surfaces and the direction of the reflective surface(s) relative to the system. The processor is arranged to determine the position of the system relative to a starting position from the derived echo data signals indicative of the distance of the system to the reflective surface(s) and the direction of the reflective surface(s) relative to the system.

Abstract: The present invention is an RF system and methods for finding a target T in three dimensional space configured to have a transponder disposed on the target T, a monitoring unit configured as a transceiver for determining or monitoring the location of the target T and an RF wireless communication system configured with a processor to repeatedly determine position, communication and other values between the transponder and monitoring unit and so as to generate a measured distance between units in three dimensional space by determining the measured distance of the target T by a spherical virtual triangulation relationship when successive values of said position information has a predetermined logical relationship relative to said previous values between said monitoring unit and transponder and/or slave unit disposed on the target T.

Abstract: A system and method for highly selective intrusion detection using a sparse array of time modulated ultra wideband (TM-UWB) radars. Two or more TM-UWB radars are arranged in a sparse array around the perimeter of a building. Each TM-UWB radar transmits ultra wideband pulses that illuminate the building and the surrounding area. Signal return data is processed to determine, among other things, whether an alarm condition has been triggered. High resolution radar images are formed that give an accurate picture of the inside of the building and the surrounding area. This image is used to detect motion in a highly selective manner and to track moving objects within the building and the surrounding area. Motion can be distinguished based on criteria appropriate to the environment in which the intrusion detection system operates.

Abstract: A positioning system includes a passive, isotropic reflecting landmark at a fixed position and a device. The device transmits an electromagnetic pulse having a circular polarization and receives a return signal over a period of time. The return signal includes a reflected pulse from the reflecting landmark. The processes the return signal to isolate the reflected pulse from the return signal and to determine a range from the device to the reflecting landmark. The reflecting landmark includes a first passive reflector, a second passive reflector, and a static structure configured to statically position the second passive reflector at an angle relative to the first passive reflector. The device optionally moves in a particular direction while receiving the return signal, detects a Doppler shift in the reflected pulse portion of the return signal, and determines an angle between the particular direction and a straight line between the device and the landmark.

Abstract: To provide a positioning system, a positioning method, and a positioning server, which are capable of improving accuracy in detection of a position. In a positioning system, three or more access points connected to a terminal station by wireless communication are connected to a positioning server through a network, the access points transmit, to the positioning server, information regarding times of having received a signal transmitted from any one of the access points or the terminal station, and the positioning server measures a position of the terminal station based on the information regarding the times, the information having been received from the access points.

Abstract: A positioning system for tracking the location of a first responder emergency worker. The system includes mobile enabler units and a personnel badge having a ranging transponder. Two enabler units can use two-way ranging signals, a prescribed turn around time and differential altitude for automatically tracking the location of the badge.

Abstract: A method and apparatus are disclosed that enable an over-the-horizon-radar (OTHR) system to detect and track multiple target classes simultaneously, where target classes are defined by the speed and acceleration of the tracked objects. The OTHR is tasked in a staring mode, with a bandwidth and waveform repetition frequency that enable detection of Doppler shifts from all target types, with sufficient clutter reduction and range resolution. The backscattered echoes are buffered for each target class and processed independently. The output of an automatic tracking algorithm then preferentially plots target progress on a single digital map for all target classes.

Abstract: A collision detection system and method of estimating a crossing location are provided. The system includes a first sensor for sensing an object in a field of view and sensing a first range defined as the distance between the object and the first sensor. The system also includes a second sensor for sensing the object in the field of view and sensing a second range defined by the distance between the object and the second sensor. The system further includes a controller for processing the first and second range measurements and estimating a crossing location of the object as a function of the first and second range measurements. The crossing location is estimated using range and range rate in a W-plane in one embodiment and using a time domain approach in another embodiment.

Abstract: A system and method for highly selective intrusion detection using a sparse array of time modulated ultra wideband (TM-UWB) radars. Two or more TM-UWB radars are arranged in a sparse array around the perimeter of a building. Each TM-UWB radar transmits ultra wideband pulses that illuminate the building and the surrounding area. Signal return data is processed to determine, among other things, whether an alarm condition has been triggered. High resolution radar images are formed that give an accurate picture of the inside of the building and the surrounding area. This image is used to detect motion in a highly selective manner and to track moving objects within the building and the surrounding area. Motion can be distinguished based on criteria appropriate to the environment in which the intrusion detection system operates.

Abstract: A real-time signal processing engine robustly detects, localizes, tracks and classifies ground targets based on radar signals from a multistatic radar system. The system differentiates between different targets based on an optimized cost function, which can include the total returned normalized pulse energy. The local transmitters/receivers can communicate with each other via the transmitted radar signals.

Abstract: The present invention relates systems and methods to determine the location information of a signal made from a radioactive device or hazardous material. The system employs multiple radiation sensor devices, which his capable of determining the signal strength and the angle of arrival of a radioactive signal. The mobile switching center sends a request along with radiation information to a location processor, which controls devices. The location processor sets up each sensor device to track the radiation signal. If at least two devices are successful in tracking the radioactive signals and returning information about the radiation signal, then the location processor can determine the location of the radioactive device or hazardous material by using a triangulation method.

Abstract: A radar transmitter is at a first location on a moving platform and illuminates a target with a sequence of frequency modulated radar pulses. The frequency modulated pulses are linear frequency modulated, i.e. chirped. The target reflects the frequency modulated radar pulses. A receiving antenna has a difference pattern null and receives the reflections from the target as a main scatterer and an ambiguity of the main scatterer. The sequence of pulses change the start of their frequency modulation (chirp) over a SAR array. The change in start frequency from pulse to pulse allows to shift the range ambiguity so as to align with the delay/Doppler difference pattern null of the antenna. Thus, both the main scatterer as well as the shifted range ambiguity are on the difference pattern null, facilitating their cancellation.

Abstract: A system for tracking an object in space for position, comprises a transponder device connectable to the object. The transponder device has one or several transponder aerial(s) and a transponder circuit connected to the transponder aerial for receiving an RF signal through the transponder aerial. The transponder device adds a known delay to the RF signal thereby producing an RF response for transmitting through the transponder aerial. A transmitter is connected to a first aerial for transmitting the RF signal through a first aerial. A receiver is connected to the first, a second and third aerials for receiving the RF response of the transponder device therethrough. A position calculator is associated to the transmitter and the receiver for calculating a position of the object as a function of the known delay and the time period between the emission of the RF signal and the reception of the RF response from the first, second and third aerials. A method is also provided.

Abstract: The present invention provides a ball measuring apparatus capable of measuring a trajectory of a ball from a hitting position to a landing position, the landing position and a stop position. A ball measuring apparatus 100 according to a first embodiment includes a first millimeter wave radar device 1 capable of carrying out a measurement from the hitting position to a predetermined position of the trajectory and having at least one transmitting antenna and a plurality of receiving antennas, and a second millimeter wave radar device 2 capable of measuring the stop position and having at least one transmitting antenna and a plurality of receiving antennas. A ball measuring apparatus 101 according to a second embodiment has a millimeter wave radar device 31 and a CCD camera 32.

Abstract: A positioning system includes a device, having an antenna and a reflector with a known position proximate to the antenna, that transmits at least an electromagnetic pulse having a carrier signal frequency. The device receives a return signal over a period of time, wherein the return signal includes a return pulse from an object within a radar detection area of the device and at least one multi-path pulse. The device processes the return signal so as to isolate the return pulse and the at least one multi-path pulse from the return signal. The device determines a range from the device to the object and the position of the device relative to the object. The range is determined in accordance with a time of arrival of the return pulse and the position is determined in accordance with a time of arrival of the at least one multi-path pulse.

Abstract: A wireless ranging system includes a first wireless unit and a second wireless unit spaced therefrom. The first wireless unit may include a time-of-arrival (TOA) wireless transmitter, and a near-field electromagnetic (NFE) wireless transmitter having a settable operating frequency. The second wireless unit may include a TOA wireless receiver cooperating with the TOA wireless transmitter, a NFE wireless receiver cooperating with the NFE wireless transmitter, and a ranging processor cooperating with the TOA wireless receiver. The ranging processor may generate a range estimate between the first and second wireless units, and generate an estimated operating frequency for the NFE wireless transmitter based upon the range estimate. The ranging processor may also generate a range window for the TOA wireless receiver via the ranging processor cooperating with the NFE wireless receiver, and use the range window with the TOA wireless receiver to generate a range estimate between the first and second wireless units.

Abstract: A sensory system for determining the orientation of an object, wherein the sensory system includes a plurality of non-uniformly spaced waveguide sensors or array(s) of waveguide sensors. The non-uniformly spaced waveguide sensors are responsive to received radio frequency signals wherein the received power of the signals is dependent upon the orientation of the waveguide(s).

Abstract: An effects automation system for generating control data for the control of effects devices, based on the relative position of a mobile target. The system uses stationary receivers and stationary transmitter tags coupled to the stationary receivers and a mobile transmitter tag coupled to the mobile target. The stationary receivers receive signals received from the stationary and mobile transmitter tags and then send data based on these signals to a processing hub. The processing hub uses this data to determine the relative distance between the stationary receivers and the relative distance between the mobile target and the stationary receivers. Based on these relative distances, relative position values for the effect devices are calculated by calculating the proportion of the distance between the stationary receivers associated with the position of the mobile target. Finally, the relative position values are utilized to generate the control data for control of the effects devices.

Abstract: A method for detecting an object using a transmitting antenna and an array of receiving antennas. The method comprises the step of transmitting a signal from the transmitting antenna. The magnitude and phase of a respective received signal at each of the receiving antennas is then measured. Next, the magnitude of a weighted sum of respective phase-compensated signals related to each of the receiving antennas is determined. The magnitude of the weighted sum is compared against a first predetermined threshold value and, optionally, a second predetermined threshold value. An object may be detected by considering a ratio of the magnitude of the weighted sum to the first predetermined threshold value and, optionally, to the second predetermined threshold value. In some embodiments, a second array of receiving antennas may be provided to facilitate the determination of the location of the object.

Abstract: A method and apparatus for use in determining the range in a single time sample from a platform to a target are disclosed. The method includes receiving radiation emanating from the target at two points on the platform in a common time sample; detecting the received radiation and generating a signal representative thereof; and processing the signal. The signal is processed to determine a respective angle to target from two points on the platform by using a correlation between received signal amplitude and respective angle; and determine the range from the platform to the target from the respective angles and the separation distance between said two points in a single signal-to-noise sufficient sample. The apparatus includes a plurality of optical channels through which the apparatus can receive radiation emanating from the target, the optical channels and a plurality of electronics.

Abstract: A method for object detection using vehicle-mounted sensors is provided, the sensing ranges of which sensors overlap at least partially. In this context, signals of at least two sensors having sensing ranges with essentially identical coverage, and additional signals of at least one additional sensor having a sensing range which only partially overlaps with the sensing ranges of the at least two sensors, are evaluated. An object is identified as relevant when it is detected by at least three of the sensors.

Abstract: A single transmit multi-receiver modulation radar modulates radar return signals received through an associated receive-signal path with one of a plurality of differing modulation waveforms having low-cross correlation products. Each receive-signal path may be associated with a different receive direction. The differently modulated return signals from each receive-signal path may be combined and correlations may be performed on the combined and differently modulated radar return signals using the modulation waveforms to locate a target. In some embodiments, the trajectory of the target may be extrapolated and the target's source location may be determined.

Abstract: A system and method for determining a position of a target within an acceptable tolerance using an iterative approach. A airborne or space-based measuring device is used to measure an estimated position of the target. The information from the measuring device is used in conjunction with either live captured or stored topography, or the like, information relating to the surface of the planet proximate the target to iteratively determine the actual position of the target.

Abstract: A system and method involve tracking the location of objects within an area of interest using transmitted-reference ultra-wideband (TR-UWB) signals. The system includes at least three base stations communicating with a central processor, at least one mobile device and at least one fixed beacon transmitter of known location. The mobile device is equipped with a transmitter for transmitting a TR-UWB signal to a base station, which then determines a location of the mobile device based on time difference of arrival information between the beacon transmitters and mobile devices measured at all the base stations. Preferably, the area of interest includes a plurality of mobile devices each transmitting a delay-hopped TR-UWB signal according to a code-division multiple access scheme. The mobile devices may be attached to a patient and/or a medical asset within the hospital for tracking purposes.

Abstract: The performance and ease of management of wireless communications environments is improved by a mechanism that enables access points (APs) to perform automatic channel selection. A wireless network can therefore include multiple APs, each of which will automatically choose a channel such that channel usage is optimized. Furthermore, APs can perform automatic power adjustment so that multiple APs can operate on the same channel while minimizing interference with each other. Wireless stations are load balanced across APs so that user bandwidth is optimized. A movement detection scheme provides seamless roaming of stations between APs.

Abstract: A system and method of dynamically updating an almanac of base stations with wireless phones that are controlled by end users. First, second, and third location information are received respectfully from a first, second, and third wireless phones. A position of each wireless device is known. The distance between each wireless device an uncooperative base station is determined while accounting for an uncertainty factor. A location of the uncooperative base station is calculated using the first, second, and third location information and the distances. The almanac is updated with the location.

Abstract: A positioning system includes a passive, isotropic reflecting landmark at a fixed position and a device. The device transmits an electromagnetic pulse having a circular polarization and receives a return signal over a period of time. The return signal includes a reflected pulse from the reflecting landmark. The processes the return signal to isolate the reflected pulse from the return signal and to determine a range from the device to the reflecting landmark. The reflecting landmark includes a first passive reflector, a second passive reflector, and a static structure configured to statically position the second passive reflector at an angle relative to the first passive reflector. The device optionally moves in a particular direction while receiving the return signal, detects a Doppler shift in the reflected pulse portion of the return signal, and determines an angle between the particular direction and a straight line between the device and the landmark.

Abstract: The performance and ease of management of wireless communications environments is improved by a mechanism that enables access points (APs) to perform automatic channel selection. A wireless network can therefore include multiple APs, each of which will automatically choose a channel such that channel usage is optimized. Furthermore, APs can perform automatic power adjustment so that multiple APs can operate on the same channel while minimizing interference with each other. Wireless stations are load balanced across APs so that user bandwidth is optimized. A movement detection scheme provides seamless roaming of stations between APs.

Abstract: The present invention relates to a system and a method for location determination using time differences. The method of the invention comprises the steps of: transmitting a transmission signal by using a directional transmitter rotating at an angular velocity, the transmission signal comprising a transmission identification and the transmitting time; receiving the transmission signal by using an omnidirectional transceiver, and adding a personal identification to the transmission signal to be a response signal; transmitting the response signal; receiving the response signal by using an omnidirectional receiver and recording the receiving time; and calculating the location of the omnidirectional transceiver corresponding to the directional transmitter according to the difference between the receiving time and the transmitting time.

Abstract: A multistatic radar has a radar transmitter for illuminating a target with a radar signal. The target reflects the radar signal to three separate radar receivers, each performing a bistatic range measurement to the target. The three bistatic range measurements are combined in a quadratic equation having two solutions (roots). One solution (root) corresponds to a correct three dimensional target position with respect to the radar transmitter while the other is an incorrect three dimensional target position with respect to the radar transmitter. The incorrect three dimensional target position is identified and eliminated by comparing the three dimensional target position to the transmitter location, and the receiver locations. The incorrect three dimensional target position is also identified by the target altitude exceeding a threshold, typically set above 80,000 feet AGL.

Abstract: A real-time signal processing engine robustly detects, localizes, tracks and classifies ground targets based on radar signals from a multistatic radar system. The system differentiates between different targets based on an optimized cost function, which can include the total returned normalized pulse energy. The local transmitters/receivers can communicate with each other via the transmitted radar signals.

Abstract: This invention is a system and method of locating a target using distributed antenna. The antenna consists of several receiving elements in known locations. At least one of the receiving elements is also a transmitter and transmits an interrogation signal to a target. The return signal from the target is received by a plurality of receiving elements and the target's position is calculated using the time of arrivals of the reply signal and the round trip delay between the transmission of the interrogation signal and the reception of the subsequent reply signal.

Abstract: A method and a system of triangulating an object by means of at least two sensors. Each sensor is placed in a respective local reference system. Each of the at least two sensors at least provide a bearing to the object in their respective local reference system. According to the invention a triangulation reference system is created. The triangulation reference system is different to any one of the local reference systems and suitably such that at least two local reference systems are rotated more in relation to each other than each one is in relation to the triangulation reference system. Sensor positions and bearings are transformed into the triangulation reference system where the triangulation is performed. Suitably the triangulated position is then transformed into a desired reference system.

Abstract: A bistatic radar has a radar transmitter at a first location on a moving platform having a motion and a radar receiver at a second location, remote from the first location. The transmitter illuminates a target along an indirect path with an encoded radar signal. The target reflects the encoded radar signal to the radar receiver. The transmitter concurrently provides the encoded radar signal to the radar receiver along a direct path. The encoded radar signal is radiated at a start time from a central reference point, and contains the first location, the pulse start time, the central reference point and the motion of the moving platform. Bit synchronization codes are also included. The radar receiver receives the encoded radar signal from the radar transmitter along the direct path during a first time interval, and the same encoded radar signal reflected from the target along the indirect path during a second time interval.

Abstract: Methods and apparatuses for detecting, locating, and identifying microwave transmitters and receivers at distant locations are disclosed. First and second electromagnetic beams at first and second frequencies, respectively, are transmitted in first and second directions. The second frequency is offset from the first frequency to define an interference difference frequency. As such, the first and second electromagnetic beams interfere at a far field distance corresponding to an intersection of the first and second electromagnetic beams. In the far field the beams interfere with microwave devices that reradiate a return radiation at the difference frequency. The methods and apparatuses detect the return radiation at the difference frequency, such as by way of a receiver, and locate the interference zone to determine the location of the microwave device, such as by a processor.

Abstract: Frequency calibration of a bi-static type of radar system is performed by positioning radar transmitter and receiver in spaced relation to each other over a targeted seawater surface from which radar radiation along a forward radiation scattering path is reflected toward the receiver while radar energy is also radiated along a direct path to the receiver by-passing the seawater during sequential frequency measurement tests to determine a frequency diffraction factor. A radiation blocking barrier is positioned by a floating support at a reflection location at an angular position on the seawater surface for intersection by the forward scattering path to block reflection of radar energy radiation toward the receiver during one of the measurement tests.

Abstract: A security system is described which includes a base station, at least one calibration unit and at least one sensor module having at least one sensor therein. The calibration unit is configured to provide signals to the at least one sensor module. The signals contain data configured to at least partially enable each sensor module to determine its location within a coordinate system. Each sensor module is further configured to transmit module location data, module orientation data, and sensor status from each sensor to the base station.

Abstract: An intrusion detection system and method are provided that can utilize impulse radio technology to detect when an intruder has entered a protection zone. In addition, the intrusion detection system and method can utilize impulse radio technology to determine a location of the intruder within the protection zone and also track the movement of the intruder within the protection zone. Moreover, the intrusion detection system and method can utilize impulse radio technology to create a specially shaped protection zone before trying to detect when and where the intruder has penetrated and moved within the protection zone.

Abstract: A primary transceiver of a primary vehicle transmits a first transmission signal to a first transponder and a second transponder associated with a secondary vehicle. A first transponder antenna and a second transponder antenna are associated with secondary vehicular reference points. Upon receipt of the first transmission signal, the first transponder transmits a second transmission signal to a first beacon of the primary vehicle and the primary transceiver. A transmitter antenna and the first beacon antenna are associated with primary vehicle reference points. Upon receipt of the first transmission signal, the second transponder transmits a third transmission signal to the first beacon and the primary transceiver. A data processor or estimator determines propagation times associated with the first transmission signal, the second transmission signal, and the third transmission signal.

Abstract: Surveillance systems and methods having both a radio frequency component and a video image are provided. The radio frequency component can determine the orientation and position of an RFID tag within a surveillance area. The orientation of the RFID tag is can be determined with respect to two or more orthogonal planes using inductance and a predetermined number of mutually orthogonal antenna loops.