Abstract: The invention relates to an apparatus for determining information on a position of a transmitter with an antenna apparatus, a control apparatus and a data processing apparatus. The antenna apparatus includes several different directional characteristics that each relate to an amount of spatially different receive sensitivities of the antenna apparatus. The antenna apparatus includes signal outputs, wherein the directional characteristics are allocated to the signal outputs. The control apparatus connects one signal output of the antenna apparatus to an information reading apparatus and further signal outputs of the antenna apparatus to the data processing apparatus. The information reading apparatus determines data transmitted with the signals from the received signals. The data processing apparatus evaluates received signals with respect to their physical characteristics. Further, the invention relates to a respective method.

Abstract: Methods and apparatus are disclosed for detecting a wirelessly detectable object. The wirelessly detectable object may include an antenna and a passive variable-frequency transponder circuit that is communicatively coupled to the antenna. The passive variable-frequency transponder circuit is powered by an interrogation signal received from an external source, and returns via the antenna a wireless response signal having a frequency that varies over a single interrogation cycle. Such variation may be based upon a decaying control voltage that controls the value(s) of one or more components in the passive variable-frequency transponder circuit and/or a switch that selectively couples and decouples components in the passive variable-frequency transponder circuit. The variable frequency may provide a characteristic signature for the wireless response signal that may be used to identify the wirelessly detectable object.

Abstract: A portable computing device may comprise a display, a frame, and a communication circuit. The frame may support the display. At least a portion of the frame may be electrically conductive, and the electrically conductive portion of the frame may define a slot. The communication circuit may be coupled to the slot. The communication circuit may be configured to generate a fringing field. The fringing field may include electromagnetic waves with a wavelength at least eight times a width of the slot in a widest direction of the slot.

Abstract: A radio IC device includes an electromagnetic coupling module includes a radio IC chip arranged to process transmitted and received signals and a feed circuit board including an inductance element. The feed circuit board includes an external electrode electromagnetically coupled to the feed circuit, and the external electrode is electrically connected to a shielding case or a wiring cable. The shielding case or the wiring cable functions as a radiation plate. The radio IC chip is operated by a signal received by the shielding case or the wiring, and the answer signal from the radio IC chip is radiated from the shielding case or the wiring cable to the outside. A metal component functions as the radiation plate, and the metal component may be a ground electrode disposed on the printed wiring board.

Abstract: An apparatus and method for wireless communications configured to receive simultaneous transmissions from a plurality of wireless devices, with each of the transmissions having a reference signal, acquire the reference signals and, based on information obtained from the acquisition of the reference signals, select the transmission from one of the wireless devices for timing synchronization and decoding.

Abstract: The present invention is a stackable telemetry circuit board for use in telemetry systems for satellites and other purposes. The present invention incorporates previously-qualified interchangeable circuit boards, or “decks,” that perform functions such as power, signal receiving and transmission, and processing. Each deck is adapted to serve a range of telemetry applications. This provides flexibility in the construction of the stackable telemetry circuit board and significantly reduces the cost and time necessary to develop a telemetry system.

Abstract: A digital processing device capable of receiving an additional service is disclosed. In one aspect, a digital processing device includes i) an input unit, inputting a signal, ii) a subscriber identity unit, storing an identity code of a communication operator and generating a communication network access request message, iii) an additional service identity unit, storing an identity code of an additional service operator and generating an additional service request message and v) a control unit, generating a control signal allowing one of the subscriber identity unit and the additional service identity unit to be selectively driven. In accordance with at least one inventive embodiment, a user of the digital processing device can receive an additional service without his or her subscription to a specific communication operator and use various additional services in addition to the additional services provided by the subscribed communication operator.

Abstract: A digital processing device capable of receiving an additional service is disclosed. In one aspect, a digital processing device includes i) an input unit, inputting a signal, ii) a subscriber identity unit, storing an identity code of a communication operator and generating a communication network access request message, iii) an additional service identity unit, storing an identity code of an additional service operator and generating an additional service request message and v) a control unit, generating a control signal allowing one of the subscriber identity unit and the additional service identity unit to be selectively driven. In accordance with at least one inventive embodiment, a user of the digital processing device can receive an additional service without his or her subscription to a specific communication operator and use various additional services in addition to the additional services provided by the subscribed communication operator.

Abstract: A method and system that prevents engagement with neutral aircraft utilizes secondary surveillance radar (SSR) in conjunction with traffic alert collision avoidance systems (TCAS) conventionally found on various commercial aircraft. The system and method provide for detecting interrogating signals sent out by a TCAS system of an interrogating aircraft searching for another aircraft that may pose a threat for collision. The system and method of the invention provide for a base system generating signals responsive to the interrogation signals such that there is a decreasing time difference between the interrogating signals and the responsive signals. The decreasing time difference indicates to the interrogating aircraft that another aircraft is approaching its airspace urging the neutral aircraft to change course and avoid entering a guarded tactical airspace thus avoiding unnecessary engagement of the aircraft.

Abstract: A telematics system in an asset network is provided. The telematics system includes one or more sensors configured to acquire data from multiple assets at different locations in the asset network. The telematics system also includes a transceiver configured to receive the data acquired from the one or more sensors. The telematics system further includes a data analysis system. The data analysis system includes a central data server configured to receive the data transmitted from the transceiver. The data analysis system also includes a processing circuitry configured to combine data, analyze combined data to detect trends, generate value added services based on the detected trends and distribute the value added services to multiple end users.

Abstract: When a lane-width-direction lateral position (X2obst+X0) of a vehicle (MM) reaches a predetermined control start position (60) being a lane-width-direction lateral position (X2obst+X0) serving as an approach prevention indicator for the vehicle (MM), a control start is determined and a yaw moment (Ms) toward the center of a vehicle traveling lane (200) is applied to the vehicle (MM) to control the vehicle (MM). Then, when the lane-width-direction lateral position (X2obst+X0) of the vehicle (MM) moves from the outside to the inside of the control start position (60), the determination of control start is suppressed for a predetermined period, compared to a period before the movement to the inside of the control start position (60).

Abstract: A system is provided, which may alternatively be implemented as a method. According to one embodiment, the system comprises an article to be tracked; a flexible radio frequency identification (RFID) device coupled to the article, the RFID device comprising a first thin flexible sheet having a first surface, a dipole antenna disposed on the first sheet, and a single integrated circuit (IC) having stored therein an identification code associated with the article. The system further comprises an article tracking system configured to receive the identification code from an interrogation system, wherein the interrogation system includes a first interrogator located at a point of origin of the article, a second interrogator located at a point of destination of the article, and a third interrogator located on a route between the point of origin and the point of destination, and wherein the first, second, and third interrogators are configured to communicate with the RFID device to determine the identification code.

Abstract: A system and method of detecting, processing, and selectively responding to radio frequency transmissions detected by at least one projectile deployed above a geographic area.

Abstract: A wide area location and telemetry system may include a wide area location and telemetry system server that is configured to determine wide area location and telemetry system data about an object when the object is located within the coverage area of the wide area location and telemetry system. The wide area location and telemetry system server may also be configured to receive localized location and telemetry system data about the object when the object is located within the coverage area of a localized location and telemetry system. The wide area location and telemetry system may also include a database and a database manager. The database manager may be configured to store the wide area location and telemetry system data and the localized location and telemetry system data in the database.

Abstract: RFID tags, tag circuits, and methods are provided that reduce at least in part the distortion to received wireless signals, which is caused by interference in the environment. Two or more thresholds are used to digitize the received signal implemented by two or more demodulators. Multiple low pass and digital filters may be implemented with the demodulators, allowing removal of narrow pulses caused by the interference and reduction of beat tone amplitude.

Abstract: A sensor includes a transceiver configured to receive a wireless signal from an interrogator and to reflect the wireless signal back. The sensor also includes an antenna-switching modulator configured to modulate a radar cross-section of the sensor by repeatedly switching an antenna between, for example, a short-circuit position and an operational circuit position. The operational circuit position could be associated with an impedance matched receiver, and the short-circuit position could be associated with ground. Also, the sensor could be further configured to transmit the wireless signal to a second sensor and to receive a reflected wireless signal from the second sensor, and the sensor could further include a phase comparator configured to compute a phase difference between the transmitted wireless signal and the reflected wireless signal. The phase comparator could be further configured to compute a distance between the sensor and the second sensor based on the phase difference.

Abstract: The invention generally relates to an airborne deployed passive radio frequency identification system and a method to identify an analyte and then to communicate a result of the analyte identification to a receiving station for an analysis and generation of a set of recommended actions. The invention will enhance the situational awareness and preparedness of forward deployed combat troops or security forces by assessing the presence of benign substances or hazardous substances as they advance and enter an area.

Abstract: A remotely configurable telematics unit cache provides for selective caching of data of interest to a remote caller. The configurable caching system ensures that selected data is available when the vehicle is not in operation and the telematics unit is not powered on. A remote caller can remotely configure the telematics unit cache to selectively store data of interest. Subsequently, the telematics module can accept calls from the caller and the cached information can be pulled. Thus, the configurable cache allows a remote caller to selectively and positively configure the cache to store desired data to be later uploaded without requiring a call-back from the telematics unit and without limiting the cached data to predetermined data groups.

Abstract: A method and apparatus for at least semi-autonomously controlling a vehicle so as to avoid collisions are provided. A sensor is utilized to scan an area proximate the vehicle for a potential object of collision. The apparatus calculates navigational states of the potential object of collision relative to the vehicle to determine that the vehicle is on a course to enter within a predetermined miss distance relative to the potential object of collision. The apparatus alters the course of the vehicle based on the calculated navigational states.

Abstract: The present invention teaches a method of manufacturing an enclosed transceiver, such as a radio frequency identification (“RFID”) tag. Structurally, in one embodiment, the tag comprises an integrated circuit (IC) chip, and an RF antenna mounted on a thin film substrate powered by a thin film battery. A variety of antenna geometries are compatible with the above tag construction. These include monopole antennas, dipole antennas, dual dipole antennas, a combination of dipole and loop antennas. Further, in another embodiment, the antennas are positioned either within the plane of the thin film battery or superjacent to the thin film battery.

Abstract: The present invention teaches a method of manufacturing an enclosed transceiver, such as a radio frequency identification (“RFID”) tag. Structurally, in one embodiment, the tag comprises an integrated circuit (IC) chip, and an RF antenna mounted on a thin film substrate powered by a thin film battery. A variety of antenna geometries are compatible with the above tag construction. These include monopole antennas, dipole antennas, dual dipole antennas, a combination of dipole and loop antennas. Further, in another embodiment, the antennas are positioned either within the plane of the thin film battery or superjacent to the thin film battery.

Abstract: In the present network system, a printer 10 periodically transmits an update request at different timings respectively to an apparatus management PC 30 and to a directory service 50 which are monitoring apparatuses for monitoring network apparatuses (such as the printer 10). Each of the monitoring apparatuses 30, 50 determines a state of the printer 10 based on the update request from the printer 10. Especially in the present system, if the apparatus management PC 30 determines that the update request from the printer 10 is not received, it notifies the directory service 50 by transmitting a delete request. As a result, early detection of disconnection of the printer 10 by the directory service 50 is possible without causing substantial increase in the network traffic.

Abstract: Process and system for the location of emitters in the radar frequency range on the basis of cross position-finding by at least two flying platforms with, in each case, at least one passive HF sensor for ascertaining the geometrical and electronic properties of the emitter beams, whereby the flying platforms mutually exchange data for describing the geometrical and electronic properties of the emitter beams, and whereby from the plurality of the position-finding beams' possible intersection points, which arise from the emitter surveying operation, use is made, in order to determine the emitter position, of those intersection points at which the electronic properties of the intersecting emitter beams are identical.

Abstract: An electromagnetic transponder comprising: an oscillating circuit; a first rectifying bridge having its A.C. input terminals connected across the oscillating circuit and having its rectified output terminals connected at least to a voltage regulator in charge of providing a supply voltage; and a second rectifying bridge, of dimension smaller than that of the first bridge, having its two A.C. input terminals connected across the oscillating circuit and having at least one output terminal connected to a demodulator of data sensed by the oscillating circuit.

Abstract: A system and method for monitoring topological changes in a defined area. A grid of sensors is arranged in the area, with known distances between them. The sensors communicate wirelessly with a host computer, which individually addresses each sensor to instruct that sensor to be in an interrogate mode or responder mode. When a sensor is in interrogate mode, it measures distance from a neighboring sensor using radar (continuous wave phase difference) measurements. When a sensor is in responder mode, it receives, delays, and returns a signal received from a neighboring sensor.

Abstract: Interfering clutter in radar pulses received by an airborne radar system from a radar transponder can be suppressed by developing a representation of the incoming echo-voltage time-series that permits the clutter associated with predetermined parts of the time-series to be estimated. These estimates can be used to estimate and suppress the clutter associated with other parts of the time-series.

Abstract: A radio frequency identification transponder includes a power supply and a dynamic memory array that stores data. When power from the power supply ceases, the data in the dynamic memory array is validly maintained for a predetermined period of time. The dynamic memory array is responsive to an interrogating signal for selectively updating the data. A radio frequency identification transponder includes a signal processor that extracts an identifier from the interrogation signal and is responsive to the identifier and the stored data to determine whether some or all of the identifier is stored in the dynamic memory array.

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: An IDT produces a SAW when excited by a single electrical pulse and can be fabricated to embody a code, which code provides for a passive autocorrelation of a SAW input to the IDT and thereby lends itself to further application as a signal generator in a communication device. However, internal dimensions of IDTs are inversely proportional to operating frequency, such that high frequency IDTs present significant manufacturing difficulties. Fabrication of IDTs for high frequency applications is simplified by exploiting a harmonic frequency SAW generated by IDTs. An IDT may therefore be designed according to fundamental frequency internal dimension criteria but can operate at a multiple of the fundamental frequency, thereby providing much higher frequency operation than conventional SAW systems. Operation of a second harmonic SAW system at 2.4 GHz based on a fundamental frequency of 1.2 GHz is contemplated.

Abstract: A surveillance system is provided for surveillance of objects within a secure area. A surveillance sensor transmits surveillance signals to all objects within the secure area, the reflections of which are received back by the surveillance sensor to determine the locations of objects, and communicates the determined locations to a pressing facility. Objects authorized to be in the secure area are equipped with an Identification Friend or Foe (IFF) unit that includes a GPS receiver and a data communication transmitter. In response to predetermined conditions, the IFF units broadcast their position and identification to the processing facility for correlation with locations defined by the reflection signals.

Abstract: A radio frequency indentification (RFID) label includes an integrated circuit and an antenna. The label may also include two flexible films directly sealed to each other. The label may be affixed to an article and used in conjunction with an interrogation system to track the article.

Abstract: A network, sensor and method are provided that utilize the capabilities of impulse radio technology to help monitor and/or control the environment within a building. In particular, the network includes a sensor attached to a first impulse radio unit that is capable of transmitting an impulse radio signal containing sensor related information to a second impulse radio unit. The second impulse radio unit is attached to a control station that uses the sensor related information (e.g., environmental related information, safety related information or surveillance related information) to monitor and/or control the environment within a building. In one aspect of the present invention, the control system can better control and monitor the environment within the building because the sensor may be moved around within the building and reference impulse radio units may interact with the first impulse radio unit to enable the determination of the current position of the sensor.

Abstract: A data carrier (1) for contactless communication with the communication station comprises firstly a reception stage (3) for receiving an interrogation signal (IS), secondly a generation stage (17) for generating a response signal (RS) upon reception of the interrogation signal (IS), thirdly a processing circuit (18) for processing the response signal (RS) into a transmission signal (MCRS) suitable for transmission to the communication station, fourthly a determination device (22) for determinating at least one representative value (REP1, REP2), the representative value (REP1, REP2) representing the field strength of the field acting on the data carrier (1), and fifthly a control connection (25) between the determination device (22) and the processing circuit (18), wherein the processing circuit (18) is influenced via the control connection (25) in order to vary a transmission parameter of a transmission signal generated by the processing circuit (18) as a function of the at least one representative value (REP

Abstract: The invention relates to a system for determining a position of a moving transponder adapted to receive a substantially stationary magnetic field signal and to transmit a further signal. The system comprises a signal generating arrangement adapted to generate said stationary magnetic field signal for said transponder, said transponder being adapted to determine a plurality of signal strengths of said received magnetic field signal; at least one signal receiving arrangement, adapted to receive said further signal of said transponder, said transponder being adapted to insert at least one message portion in said further signal indicative of at least one of said plurality of signal received signal strengths and processing means adapted to determine said position in accordance with a plurality of said received signal strengths determined by said moving transponder. This further signal can e.g.

Abstract: A system for visually indicating receipt of a radio communication directed to a user having an associated unique identification code. The system includes a radio transponder having an audio output, means for obtaining and storing the unique identification code; a speech recognition circuit operably connected to the radio transponder audio output and the stored identification code; and a visual indicator operably connected to an output of the speech recognition circuit, such that when the stored identification code and said audio input are substantially the same the visual indicator is driven to activation. A method is similarly disclosed.

Abstract: SAW devices such as interdigital transducers (IDTs) have been widely used in RADAR applications and as filters. An IDT produces a SAW when excited by a single electrical pulse and can be fabricated to embody a code, which code provides for a passive autocorrelation of a SAW input to the IDT and thereby lends itself to further application as a signal generator in a communication device. However, internal dimensions of IDTs are inversely proportional to operating frequency, such that high frequency IDTs present significant manufacturing difficulties. Fabrication of IDTs for high frequency applications is simplified by exploiting a harmonic frequency SAW generated by IDTs. An IDT may therefore be designed according to fundamental frequency internal dimension criteria but can operate at a multiple of the fundamental frequency, thereby providing much higher frequency operation than conventional SAW systems.

Abstract: An identification interrogator is provided for surveillance of objects within an area. The identification interrogator transmits interrogation signals to all objects within the surveillance area, the reflections of which are received back by the interrogator to determine the locations of the objects, and communicates the determined locations to a processing facility to determine their authorized locations. Upon receipt of interrogation signals, some of the objects within the surveillance area broadcast their position and identification to processing facility for correlation with the locations determined by the reflection signals. The locations of other objects are found by correlating the location determined by the reflection signal with a predetermined list of objects and their location within the surveillance area. These may be objects with no means or method to transmit position and identification information, such as rock formations or buildings.

Abstract: An identification interrogator is provided for surveillance of objects within an area. The identification interrogator transmits interrogation signals to all objects within the surveillance area, the reflections of which are received back by the interrogator to determine the locations of the objects, and communicates the determined locations to a processing facility to determine their authorized locations. Upon receipt of interrogation signals, some of the objects within the surveillance area broadcast their position and identification to processing facility for correlation with the locations determined by the reflection signals. The locations of other objects are found by correlating the location determined by the reflection signal with a predetermined list of objects and their location within the surveillance area. These may be objects with no means or method to transmit position and identification information, such as rock formations or buildings.

Abstract: The invention relates to a system for determining a position of a moving transponder adapted to receive a substantially stationary magnetic field signal and to transmit a further signal. The system comprises a signal generating arrangement adapted to generate said stationary magnetic field signal for said transponder, said transponder being adapted to determine a plurality of signal strengths of said received magnetic field signal; at least one signal receiving arrangement, adapted to receive said further signal of said transponder, said transponder being adapted to insert at least one message portion in said further signal indicative of at least one of said plurality of signal received signal strengths and processing means adapted to determine said position in accordance with a plurality of said received signal strengths determined by said moving transponder. This further signal can e.g.

Abstract: A tire pressure monitoring device, being installed in a motor vehicle having a plurality of tires, includes: a plurality of sensor modules being installed onto the tire and having a wireless communication signal transmitter for transmitting a radio frequency (RF) signal. The RF signal includes a specific code for the status of the tire and a specific code for the sensor module. The device further includes a plurality of antenna modules, each being installed individually for one of the sensor modules for receiving the signal; and a receiving device, electrically coupled to the antenna module for processing the signal.

Abstract: A multi-frequency RFID remote communication system is provided that includes a plurality of RFID tags configured to receive a first signal and to return a second signal, the second signal having a first frequency component and a second frequency component, the second frequency component including data unique to each remote RFID tag. The system further includes a reader configured to transmit an interrogation signal and to receive remote signals from the tags. A first signal processor, preferably a mixer, removes an intermediate frequency component from the received signal, and a second processor, preferably a second mixer, analyzes the IF frequency component to output data that is unique to each remote tag.

Abstract: The on-road reference point positional data delivery device according to the present invention has a reference point positional data delivery device, and this reference point positional data delivery device has a beacon identification device for indicating a reference point position for service information delivered from a beacon provided on a road to a vehicle and also selecting the beacon delivering the service information from among a plurality of beacons.

Abstract: Devices having either wireless data communication capability or RFID tags can be located using dual function fixed devices which are distributed throughout a facility. The devices will identify those units with which they are communicating using a wireless radio data communications protocol and also identify items within the local area using RFID tags on the units.

Abstract: A device for data transmission in a motor vehicle and/or from a motor vehicle in its vicinity includes a first transceiver unit in or on the motor vehicle and a second transceiver unit. which is provided in at least one transponder unit whose spatial position relative to the vehicle may be variable or any desired position. In the first transceiver unit is a radar unit equipped for distance measurement, expanded by adding a two-channel data transmission system. The second transceiver unit is also a two-channel data transmission unit, and the microwave frequencies for two-channel communication of the data transmission system are selected so that their difference yields an intermediate frequency which is processable using conventional components in a heterodyne receiver in the reception part of each of the first and second transceiver units.

Abstract: Disclosed herein is a critical band encoding technology (CBET) system having at least one portable people meter (PPM) and a home base station and/or household hub, the CBET system containing a radio frequency (RF) proximity detection and identification system, comprising at least one RF transmitter for receiving a control signal, modulating an RF signal to a present modulation frequency upon receipt of the control signal, and wireless transmitting the modulated signal; and an RF receiver for receiving the wirelessly transmitted modulated signal, determining the modulation frequency, and transmitting the modulation frequency to a remote location, wherein the transmission power of the RF transmitter is preset to transmit the modulated data within a predetermined range.

Abstract: A network, sensor and method are provided that utilize the capabilities of impulse radio technology to help monitor and/or control the environment within a building. In particular, the network includes a sensor attached to a first impulse radio unit that is capable of transmitting an impulse radio signal containing sensor related information to a second impulse radio unit. The second impulse radio unit is attached to a control station that uses the sensor related information (e.g., environmental related information, safety related information or surveillance related information) to monitor and/or control the environment within a building. In one aspect of the present invention, the control system can better control and monitor the environment within the building because the sensor may be moved around within the building and reference impulse radio units may interact with the first impulse radio unit to enable the determination of the current position of the sensor.

Abstract: A formation collision avoidance system includes a Traffic Alert and Collision Avoidance System (TCAS) having a passive mode and an active mode. The passive mode enables several members of an aircraft formation to fly without actively interrogating using TCAS while only one or few formation members are actively interrogating. Formation members in passive mode maintain awareness of current air and ground traffic conditions using networked surveillance information provided over a communications link between formation members in active mode and formation members in passive mode. The networked surveillance information includes positional and intent information of current air/ground traffic obtained from ADS-B broadcasts and replies to the actively interrogating members of the formation. The communications link utilizes Station Keeping Equipment (SKE) already existing on certain aircraft.

Abstract: The invention relates to a system suitable for a remote interrogation of passive transponders using chirp signals for interrogation. The transponder preferably has an encoding unit (11), a calibrating unit (12) and a measuring unit (13) each with a plurality of parallel channels (11.1 to 11.5, 12.1 and 13.1 to 13.2). The encoding unit and the calibrating unit are preferably jointly incorporated with a common delay line (14) on the same SAW chip. The interrogation signals received in the transponder via an antenna (10) are delayed characteristically and code-specifically, in particular in the encoding and calibrating unit. Decoding in the interrogation station is preformed by discrete Fourier transformation of the response signal and subsequent evaluation of the spectrum. To correct general disturbing influences on the delay of the response signal, said signal is calibrated using a single calibrating component in the response signal.

Abstract: The present invention provides an apparatus, method, and system for determining a time of arrival (TOA) and time differences of arrival (TDOA) of a transmitted signal {S} receivable at different locations of known spatial coordinates. The system comprises a first transmitter 10 with a respective antenna feed point positioned at an a priori unknown location P and emitting a first signal {S}. The system includes furthermore a set of transceivers or transponder units 20, 30 comprising first receivers 22, 32 for receiving first signals {S} by means of respective antennas with feed points located at known locations Ln. Such system also comprises second transmitters 26, 36 emitting respective derived second signals {{tilde over (S)}n} after known and scheduled respective time intervals &dgr;n as measurable between the feed points of said respective first receiving antennas located at known locations Ln and respective second transmitting antenna located at locations L′n.

Abstract: A police activity transponder utilizes data available through a vehicle on-board diagnostic system or a intelligent vehicle data bus to adjust the sensitivity of the police activity transponder to law enforcement signals based on speed data. A police activity transponder is configured to read speed data available through an on-board diagnostic system or an intelligent vehicle data bus and using an internal clock, calculate a 0 to 60 mile per hour or a quarter mile time for display and function as a speedometer. A police activity transponder is configured to read engine revolutions per minute (rpm) data and function as a tachometer. A police activity transponder is configured to allow a user to input shift points, read engine rpm data, and provide a user indication.