Abstract: Disclosed is a SONAR system operable to transmit a pair of pulses including an up-chirp signal and a down-chirp signal wherein the down-chirp signal is a time-reversed version of the up-chirp signal. Also disclosed is a related method of operation.

Abstract: A synthetic aperture radar (SAR) is operable in an interrogation mode and in an imaging mode, the imaging mode entered in response to determining a response to interrogation pulses have been received from a ground terminal and position information specifying a ground location has been received from the ground terminal. A ground terminal is operable to receive interrogation pulses transmitted by a SAR, transmit responses, and transmit position information to cause the SAR to enter a imaging mode. The ground terminal receives first and subsequent pulses from the SAR where subsequent pulses include backscatter and are encoded. The ground terminal generates a range line by range compression. If the SAR is a multi-band SAR the transmitted pulses can be in two or more frequency bands, and subsequent pulses in one frequency band can include encoded returns from pulses transmitted in a different frequency band.

Abstract: A method for determining a distance between a first radio signal transceiver and a second radio signal transceiver using narrowband ranging comprises calculating a preliminary estimate of a value proportional to a one-way frequency domain channel response, based on measurements of signal phase and signal strength; calculating, for pairs of adjacent frequencies, an estimate of a value proportional to a time synchronization offset between a clock used by the first radio signal transceiver and a clock used by the second radio signal transceiver, and determining a final estimate of a value proportional to the one-way frequency domain channel response based on the preliminary estimate and adjacent estimates for the value proportional to the time synchronization offset, where the final estimate is used for the final distance determination.

Abstract: A robotic mapping system for charting or mapping a path through an underground cavity, and/or mapping a surface of the underground cavity. The robotic mapping system may comprise a mobile control center located on the surface in wireless communications with one or more mapping robots located within the underground cavity. The mapping robots may be controlled by way of an avionics navigation system.

Abstract: Aspects of the present invention relate to methods, systems, and computer-readable media for triggering an identification signal broadcast of a first navigational aid equipment using a tone in the voice band transmitted by a second navigational aid equipment. Aspects include receiving, at the first navigational aid equipment, a tone in a voice band of second navigational aid equipment. Aspects also include transmitting, by the first navigational aid equipment, the identification associated with the first navigational aid equipment identification when the tone is received.

Abstract: Systems, devices, and methods are described for providing, among other things, a wheelchair-assist robot for assisting a wheelchair user with everyday tasks or activities at work, at home, and the like. In an embodiment, the mobile wheelchair-assist robot includes a wheelchair interface component configured to exchange control information with a wheelchair controller. In an embodiment, a wheelchair-assist robot mount assembly is provided for, among other things, electrically and physically coupling a wheelchair-assist robot to an associated wheelchair.

Abstract: A method for measuring distance includes transmitting a first pair of RF pulses from an airborne interrogator, where the first pair of RF pulses are temporally separated from each other by a first time interval and each of the RF pulses in the first pair of RF pulses has a first pulse waveform. The method also includes receiving a second pair of RF pulses transmitted by a ground transponder. The RF pulses in the second pair of RF pulses have a second pulse waveform characterized by a smoothed concave polygonal function and/or a smoothed concave hexagonal function. The method further includes determining an elapsed time between transmitting the first pair of RF pulses and receiving the second pair of RF pulses and determining a distance between the airborne interrogator and the ground transponder based on at least the elapsed time.

Abstract: An avionics system allows aircraft to introduce bogus “ADS-B Out” messages that are recognized as false only by authorized users. The system enables aircrafts flying at low altitudes to prevent misuse of their ADS-B Out information by maliciously operated cyber and physical attack tools. Aspects of the illustrative embodiment include the system architecture, including an Airborne ATC Processor and Ground ATM System Processor; a process employed by aircraft for generating authorized bogus ADS-B Out messages; a process employed by aircraft for transmitting authorized bogus ADS-B Out messages; and a process employed by air traffic control and other aircraft for decoding the authorized bogus ADS-B Out messages.

Abstract: In one embodiment, a method includes receiving a radio frequency (RF) signal; synchronizing the received RF signal with a preamble to determine a time base; determining a first energy value of the received RF signal by averaging received signal strength indication (RSSI) values of the received RF signal over a first period of time; determining a second energy value of the received RF signal over a second period of time; determining a difference value between the first energy value and the second energy value; comparing the difference value with a predetermined energy threshold value; determining a quality value of the received RF signal; comparing the quality value of the received RF signal with a predetermined quality threshold value; and, if the difference value exceeds the predetermined energy threshold value or the quality value is below the predetermined quality threshold value, then erasing the time base.

Abstract: A vehicle detection system for determining the position of a trailing section relative to a forward section of a vehicle, such as a tractor-trailer combination. The trailing section is pivotally coupled to the forward section for driving movement therewith. The vehicle detection system includes a central controller and a detection system connectable to the forward section of the vehicle and operably coupled to the central controller. The detection system outputs a detection signal. A target device is connectable to the trailing section and configured to receive the detection signal from the detection system and output a unique return signal to the detection system. The detection system receives the return signal and transfers the return signal or other indicative signal for processing by the central controller, whereby the central controller determines position information of the trailing section, for potential use by a DSRC.

Abstract: Systems and methods that allow for distance-measuring equipment (DME) to use either a lower or an upper fuselage-mounted antenna. An exemplary system located on an aircraft includes an aircraft configuration data source that generates aircraft configuration information, an aircraft orientation data source that generates aircraft orientation information, a positioning system that generates aircraft position information and a component that provides DME ground station position information. The system also includes a first antenna, a second antenna and a processing device that determines if a DME signal communication issue exists with the first antenna that is based on the generated aircraft position information, the DME ground station position information and at least one of the configuration or orientation information. The processing device switches DME signal communication to the second antenna if a DME signal communication issue has been determined to exist.

Abstract: Various avionics systems may benefit from the proper handling of diversity with respect to antennas. For example, systems and methods for remote L-band smart antenna distance measuring equipment may benefit from being prepared to provide diversity against interference, such as a multipath interference. A method can include determining which antenna of a plurality of antennas of an aircraft is preferred for communication with respect to distance measuring equipment. The method can also include selecting the antenna based on the determination.

Abstract: Method for determining the overall length (GL) of a jib (1, 4) of a crane in a wear-free manner, characterized in that a signal is coupled in at a first point (2, 5) of the jib (1, 4) and is coupled out at a second point (3, 6) of the jib (1, 4), the overall length (GL) being determined from the time required for the signal to go from the first point (2, 5) to the second point (3, 6).

Abstract: Described is a technology by which a gesture made with a source device (e.g., a cellular telephone), such as a throwing or pointing motion, is used to automatically set up a connection with another device to which the gesture is directed. Audio signals output during the gesture, e.g., such as at the start and end of the gesture, are detected by candidate (listening) devices. The device having the least time difference between detection of the start and end signals is the device that is generally best aligned with the throwing or pointing motion, and thus may be selected as the target device. Once selected, a connection such as a network connection may be set up between the source device and the target device for further communication, such as for application data exchange.

Abstract: A ranging and positioning system comprising transmitters and receiver nodes communicating together by chirp-modulated radio signals, that have a ranging mode in which ranging exchange of signals takes place between a master device and a slave device that leads to the evaluation of the range between them. The slave is arranged for recognizing a ranging request and transmit back a ranging response containing chirps that precisely aligned in time and frequency with the chirps in the ranging requests, whereupon the master can receive the ranging response, analyze the time and frequency the chirps contained therein with respect to his own time reference, and estimate a range to the slave.

Abstract: A method, system, and device provide asymmetric round-trip-time (RTT) ranging with multipath correction. A RTT ranging determination using the resulting composite received signal contains multipath error, and compensation or correction of this error in a manner compatible with low-power, low-complexity devices, such as tag devices, is provided.

Abstract: The present invention provides a system and method for aircraft to determine own position and navigate using a navigation heartbeat signal broadcast on a DME uplink and/or a Mode-S uplink frequency. The present invention enables deep integration between the existing navigation systems (DME interrogation-reply ranges and GPS/WAAS raw TDOA or pseudo range measurements) and the DME heartbeat TDOAs or Mode-S heartbeat TDOAs to provide a highly accurate navigation positioning capability and provide necessary backup capability in lieu of GPS to maintain the necessary RNP/RNAV capability and avoid degrading aircraft operational safety.

Abstract: A method and system for identification, tracking and locating in wireless communications and wireless networks. The method and system use reference and/or pilot signals that are present in wireless communications and wireless networks. The method and system can also use RTT, TOA and time-stamping measurements/techniques to determine one or more reference signals traveling time between the Base Station (eN B) or its functional equivalent and mobile device (UE) and or network device. The method and system includes multi-path mitigations processor and multi-path mitigations techniques and algorithms which improve the track-locate accuracy. The method and system allow achieving increased accuracy by using multi-path mitigations processor and multi-path mitigations techniques and algorithms. The techniques of Digital Signal Processing and Software-Defined Radio are used.

Abstract: Systems and methods that allow for distance-measuring equipment (DME) to use either a lower or an upper fuselage-mounted antenna. An exemplary system located on an aircraft includes an aircraft configuration data source that generates aircraft configuration information, an aircraft orientation data source that generates aircraft orientation information, a positioning system that generates aircraft position information and a component that provides DME ground station position information. The system also includes a first antenna, a second antenna and a processing device that determines if a DME signal communication issue exists with the first antenna that is based on the generated aircraft position information, the DME ground station position information and at least one of the configuration or orientation information. The processing device switches DME signal communication to the second antenna if a DME signal communication issue has been determined to exist.

Abstract: Systems and methods for providing an improved multiradio system. An exemplary system includes first and second antennas and a first receiver that receives a signal from the first antenna, filters the received signal based on bandwidths associated with a traffic collision-avoidance system (TCAS), a transponder, and a universal access transceiver (UAT). The system digitizes the filtered signal and digitally downconverts the digitized signal. A second receiver receives a signal from the second antenna, filters the signal received from the second antenna based on the TCAS, the transponder, the UAT, and distance-measuring equipment (DME), separates the filtered signal into a first signal having a bandwidth associated with the TCAS, the transponder, the UAT and the lower half of the DME RF band, and into a second signal having a bandwidth associated with the upper half of the DME RF band, digitizes the first and second signal, and digitally downconverts the digitized first and second signals.

Abstract: Described is a technology by which a gesture made with a source device (e.g., a cellular telephone), such as a throwing or pointing motion, is used to automatically set up a connection with another device to which the gesture is directed. Audio signals output during the gesture, e.g., such as at the start and end of the gesture, are detected by candidate (listening) devices. The device having the least time difference between detection of the start and end signals is the device that is generally best aligned with the throwing or pointing motion, and thus may be selected as the target device. Once selected, a connection such as a network connection may be set up between the source device and the target device for further communication, such as for application data exchange.

Abstract: A locating system, includes at least one initiator configured to operate at a first clock frequency, and to transmit a measurement signal including a first preamble; and at least one transponder configured to operate at a second clock frequency, to receive the measurement signal, and to transmit a response signal to the initiator, the response signal including a second preamble. The initiator is further configured to calculate, based on the response signal, a distance between the initiator and the transponder for determining a location of the transponder.

Abstract: A method and system for identification, tracking and locating in wireless communications and wireless networks. The method and system use reference and/or pilot signals that are present in wireless communications and wireless networks. The method and system can also use RTT, TOA and time-stamping measurements/techniques to determine one or more reference signals traveling time between the Base Station (eNB) or its functional equivalent and mobile device (UE) and or network device. The method and system includes multi-path mitigations processor and multi-path mitigations techniques and algorithms which improve the track-locate accuracy. The method and system allow achieving increased accuracy by using multi-path mitigations processor and multi-path mitigations techniques and algorithms. The techniques of Digital Signal Processing and Software-Defined Radio are used.

Abstract: A method and RFID tag for locating RFID tags. A passive RFID tag A receives a polling command transmitted from a RFID reader and addressed to another passive RFID tag B. The RFID tag A determines that the polling command is not addressed to the RFID tag A and consequent1y, at time t1, switches the RFID tag A to a catching mode for catching echos from other tags. The RFID tag A receives at time t3>t1 an echo of a message sent by the RFID tag B to the RFID reader. The RFID tag A determines a distance (D.t2t) between the RFID tag A and the RFID tag B based on t3 minus t1. The distance D.t2t does not exceed a specified radius limit and the identification of the RFID tag B and the distance D.t2t are stored in a database within the RFID tag A.

Abstract: A high-precision distance measuring with a reduced error in a distance measuring system which calculates a distance from an arrival time of each pulse signal constituting a pulse sequence is provided. For an oscillator which generates pulse signals by counting the number of pulse signals constituting a received pulse sequence, a relative time difference between a transmitting device and a return device is acquired, a distance from the transmitting device to the return device is calculated, and the calculated distance is corrected based on the calculated relative time difference.

Abstract: The invention relates to an automatic aircraft landing guidance system having an electromagnetic detecting and locating device, positioned on the ground and a first multifunction transmitting/receiving radiofrequency beacon, on board each guided aircraft and transmitting in particular a continuous wave. The detecting and locating device uses the continuous wave transmitted by the beacon to perform a passive locating intended to improve the accuracy of the measurement of the angular position of the aircraft. It also comprises means for generating and periodically transmitting to the aircraft, via the beacon, information enabling said aircraft to rejoin an optimum landing path from its position. The invention applies more particularly to the guidance of autonomous and automatic aircraft such as drones in the approach and landing phase.

Abstract: Techniques are generally disclosed for communications between a locator device and a transponder device. The locator device may be located in a space based location such as on a surface of a remote celestial body, on a space craft or space station, on a satellite, or on a low earth orbit aircraft. The locator can encode an interrogation signal for receipt by one or more distant transponders. The transponder devices can receive the communications from the distant locator device and determine frequency, phase, cadence, and Doppler for encoding a reply transmission to the locator device. The encoding process estimates Doppler shift and adapts the reply transmission for a quantized reverse Doppler shifted frequency and cadence, which effectively pre-compensates for the Doppler shift that will be apparent to the locator due to the relative velocity. The locator can use the Doppler quantization scheme to reconstruct the actual relative velocity.

Abstract: The present receive antenna interface for an RF (radio frequency) transceiver includes a transmitting and receiving antenna. The receive antenna interface also includes a relay and an electrically-isolated transmit-ground connector that are configured such that the receiving antenna is not capable of being used by the transceiver unless the transmit-ground connector is connected to a ground-on-transmit connector provided by the transceiver. As a result, damage from the accidental transmission of RF signals into the receiving circuitry of the transceiver is prevented.

Abstract: A wireless distance measurement system and wireless terminal improve the accuracy of distance measurement when the UWB communication scheme is used. In wireless terminal 200, a route of signals varies between a distance measuring operation and a synchronization establishing operation, and, when the distance measuring operation is performed, a detection result is inputted to comparator 208 without passing through integrator 204. By this means, the distance measuring operation of wireless terminal 200 does not involve integration processing, so that delay time due to integration processing is not produced and, consequently, it is possible to improve the accuracy of distance measurement. Further, the distance measuring operation uses the integration result acquired integrator 204 for a comparison reference voltage used in comparator 208.

Abstract: A transponder (12) transmits a reply in response to an interrogation input thereto, the interrogation including twin pulses, and a monitoring processor (13) transmits to the transponder a pseudo interrogation identical in format to the interrogation, receives from the transponder a reply responding to the pseudo interrogation, and monitors a performance of the transponder, the monitoring processor (13) including a pulse spacing adjuster (131c) operable to adjust a pulse spacing of twin pulses along with generation of the pseudo interrogation, and a monitor (134b) operable to output an alarm in response to a failed reception or a delayed reception of a reply from the transponder after transmission of a pseudo interrogation with a compliant pulse spacing, and further to output an alarm in response to a reception of a reply from the transponder after transmission of a pseudo interrogation with an uncompliant pulse spacing.

Abstract: A pulse detecting equipment includes a log compression processor (105) for logarithm-converting signal levels of a reception signal received at an antenna and input therefrom, with maintained frequency components of the reception signal as input, an AD converter (106) for converting the reception signal as logarithm-converted in signal level, from an analog form into a digital form, a first detector (110) for limiting the reception signal as converted into the digital form to a band of a prescribed first frequency, to obtain a signal, to detect signal levels thereof, a second detector (111) for limiting the reception signal as converted into the digital form to a band of a prescribed second frequency smaller than the first frequency, to obtain a signal, to detect signal levels thereof, and a pulse detector (113) for use of a result of comparison between signal levels detected at the first detector and signal levels detected at the second detector, to detect pulses of a prescribed frequency as a signal transmi

Abstract: When an excitation signal is generated from an exciter due to an activation signal generated from a radar control device and is distributed to supply to each antenna sub-module, a combination reception signal is transmitted to a receiver from each antenna sub-module. The receiver takes in the combination reception signal obtained by each sub-module in response to an instruction from the radar control device, a frequency converter converts the combination reception signal into a prescribed frequency band, and a distributed aperture combination circuit performs a beam combination in accordance with a distributed aperture combination algorithm. In this way, a radar apparatus, which is equivalent to an active phased array radar of a large aperture and with high performance, is achieved.

Abstract: The present invention utilizes the existing DME transponder system infrastructure to augment existing ground surveillance multilateration (MLAT) capabilities by providing additional measurements for determining the position of an aircraft equipped with a DME transponder. DME listeners receive DME interrogation signals and DME reply signals, determine TDOA between the DME transponder and each DME listener, and transmit data to a central computer that clusters TDOAs between the DME transponder and the DME listeners and computes the aircraft position using the clustered TDOAs. The DME-aided MLAT can be used as a backup surveillance system when GNSS-based systems are unavailable. The DME-aided MLAT can be integrated with SSR receive units (RUs) performing multilateration (MLAT) calculations.

Abstract: A method and system for identification, tracking and locating in wireless communications and wireless networks. The method and system use reference and/or pilot signals that are present in wireless communications and wireless networks. The method and system might also use RTT, TOA and time-stamping measurements/techniques to determine one or more reference signals traveling time between the Base Station (eNB) or its functional equivalent and mobile device (UE) and or network device. Other wireless networks that do not use reference and/or pilot signals may employ one or more of the following types of alternate embodiments of present invention: 1) where a portion of frame is dedicated to the ranging signal/ranging signal elements; 2) where the ranging signal elements are embedded into (spread across) transmit/receive signals frame(s); and 3) where the ranging signal elements are embedded with the data.

Abstract: By using the delay profile created by delay profile creating section 102 and the first threshold value 330 received from the first threshold value calculation 105, the first threshold value timing detection section 103 selects only the earliest receive timing exceeding the first threshold value, from all the timing that the correlation value in the delay profile becomes a maximum. By using the receive timing and the second threshold value 331 received from the second threshold value calculation section 107, reference timing calculation section 106 selects the reference timing required for calculating the receive timing for the incoming wave of the minimum propagation delay time. The timing delayed by previously set timing behind said reference timing is sent from receive timing calculation section 108 as the receive timing 113 of the incoming wave of the minimum propagation delay time.

Abstract: A method and system for a long range Radio Frequency (RF)-based identification, tracking and locating of objects. The method and system use a narrow bandwidth ranging signal(s), including VHF of lower frequency bands, which minimizes propagation loss and loss of accuracy of the RF locating signals. The method and system includes narrow bandwidth ranging signal multi-path mitigations processor, which further improves the track-locate accuracy. The signal is sent from a Master Unit(s) to a Tag. The signal traveling time is recorded and the distance between the Master(s) and the Tag is calculated. The method and system allow achieving a longer distance of the RF narrow bandwidth ranging signal penetration and an increased accuracy by using VHF bands in conjunction with the narrow bandwidth ranging signal multi-path mitigations processor. The techniques of Digital Signal Processing and Software-Defined Radio are used. The actual waveforms transmitted and received by the radios are defined by the software.

Abstract: A wireless distance measurement system and a wireless distance measurement method that measure the distance between a base station and a terminal without clock synchronization between a plurality of base stations, and without requiring input of the position relationships between a plurality of base stations. Clock phase shift section (210) shifts a clock that is used to generate transmission pulses is phase-shifted by a specific amount every 100 nanoseconds, and A/D conversion section (211) converts a signal re-radiated from terminal (103) to a digital signal using the shifted clock. Correlation calculation section (212) performs correlation calculation between the digital signal and the transmission pulse and creates a delay profile by adding digital signals in the shifted phases between same phases, and incoming wave detection section (213) detects peaks of the pulses in the delay profile.

Abstract: A transponder (12) transmits a reply in response to an interrogation input thereto, the interrogation including twin pulses, and a monitoring processor (13) transmits to the transponder a pseudo interrogation identical in format to the interrogation, receives from the transponder a reply responding to the pseudo interrogation, and monitors a performance of the transponder, the monitoring processor (13) including a pulse spacing adjuster (131c) operable to adjust a pulse spacing of twin pulses along with generation of the pseudo interrogation, and a monitor (134b) operable to output an alarm in response to a failed reception or a delayed reception of a reply from the transponder after transmission of a pseudo interrogation with a compliant pulse spacing, and further to output an alarm in response to a reception of a reply from the transponder after transmission of a pseudo interrogation with an uncompliant pulse spacing.

Abstract: A pulse detecting equipment includes a log compression processor (105) for logarithm-converting signal levels of a reception signal received at an antenna and input therefrom, with maintained frequency components of the reception signal as input, an AD converter (106) for converting the reception signal as logarithm-converted in signal level, from an analog form into a digital form, a first detector (110) for limiting the reception signal as converted into the digital form to a band of a prescribed first frequency, to obtain a signal, to detect signal levels thereof, a second detector (111) for limiting the reception signal as converted into the digital form to a band of a prescribed second frequency smaller than the first frequency, to obtain a signal, to detect signal levels thereof, and a pulse detector (113) for use of a result of comparison between signal levels detected at the first detector and signal levels detected at the second detector, to detect pulses of a prescribed frequency as a signal transmi

Abstract: [Object] To achieve high-precision distance measuring with a reduced error in a distance measuring system which calculates a distance from an arrival time of each pulse signal constituting a pulse sequence. [Solving Means] For an oscillator which generates pulse signals by counting the number of pulse signals constituting a received pulse sequence, a relative time difference between a transmitting device 2 and a return device 3 is acquired, a distance from the transmitting device 2 to the return device 3 is calculated, and the calculated distance is corrected based on the calculated relative time difference.

Abstract: The transponder unit provided in a DME ground apparatus detects the transmission rate at which to transmit the pulse-pairs constituting a response signal. The threshold of the reception level of the pulse detection unit provided in the transponder unit is raised as the transmission rate increases.

Abstract: A direction finding antenna system for determining the relative bearing of a second aircraft from a first aircraft in conjunction with Distance Measuring Equipment (DME). The system includes a first antenna and a second antenna located on a top surface of the first aircraft, spaced apart along a first axis, as well as a third antenna and a fourth antenna located on a bottom surface of the first aircraft, spaced apart along a second axis orthogonal to the first axis. The system further includes a transmitting, receiving, and processing system coupled to the first, second, third, and fourth antennas, wherein the transmitting, receiving, and processing system is configured to transmit DME interrogations, receive DME replies, and process the DME replies to determine the relative bearing of the second aircraft from the first aircraft.

Abstract: A device and a method for eliminating interference between a radar working on the L frequency band and an aeronautical radio navigation equipment item, such as DME (Distance Measurement Equipment). When the radio navigation equipment operates, the radar emits periodically in all or part of the frequency band and then halts its emissions, each emission has a given duration and being separated from the previous emission by an interval of silence.

Abstract: A transponder unit of a DME ground apparatus receives an interrogation signal and converts the same to an IF signal. The unit performs analog-to-digital conversion on the IF signal, generating a digital interrogation signal. The unit calculates two detected outputs whose frequencies are ±900 kHz deviated with respect to the center frequency of the digital interrogation signal. Then, the transponder unit compares the two detected outputs and the digital interrogation signal in terms of magnitude, thereby to determine whether a response signal should be transmitted.

Abstract: A robot platform includes perceptors, locomotors, and a system controller. The system controller executes instructions for repeating, on each iteration through an event timing loop, the acts of defining an event horizon, detecting a range to obstacles around the robot, and testing for an event horizon intrusion. Defining the event horizon includes determining a distance from the robot that is proportional to a current velocity of the robot and testing for the event horizon intrusion includes determining if any range to the obstacles is within the event horizon. Finally, on each iteration through the event timing loop, the method includes reducing the current velocity of the robot in proportion to a loop period of the event timing loop if the event horizon intrusion occurs.

Abstract: By using the delay profile created by delay profile creating section 102 and the first threshold value 330 received from the first threshold value calculation 105, the first threshold value timing detection section 103 selects only the earliest receive timing exceeding the first threshold value, from all the timing that the correlation value in the delay profile becomes a maximum. By using the receive timing and the second threshold value 331 received from the second threshold value calculation section 107, reference timing calculation section 106 selects the reference timing required for calculating the receive timing for the incoming wave of the minimum propagation delay time. The timing delayed by previously set timing behind said reference timing is sent from receive timing calculation section 108 as the receive timing 113 of the incoming wave of the minimum propagation delay time.

Abstract: This invention relates to a method for determining the reply efficiency of a DME navigation beacon and to an apparatus for performing the method. The invention involves locating an RF receiver nearby a DME beacon to be tested. The RF receiver analyses all signals received on the interrogation frequency of that beacon to determine pulse pairs which correspond to a valid interrogation of that beacon. Other pulse events of interest may also be detected. The RF receiver also records all signals on the reply frequency of the beacon and detects all replies sent by the beacon. Particular interrogations can then be correlated with replies and the reply efficiency of the beacon determined. Several RF receivers may be located round the beacon to better provide correlation between particular interrogations and responses.

Abstract: A system for identifying radio-frequency identification (RFID) devices is described. In one embodiment, RFID devices include an antenna and metallic pattern printed on a substrate. A probing platform is used to radiate the RFID devices with an electromagnetic signal (e.g., radio-frequency signal, microwave signal, etc.). Each RFID device generates a quantifiable backscatter depending on the unique impedance of the passive RFID device in response to the electromagnetic signal. The backscatter is employed to uniquely identify the passive RFID device's impendence with respect to the probing platform uniquely characterized at predetermined frequencies of the electromagnetic signal.

Abstract: In a DME ground apparatus, under the control of a transmission-rate monitoring control unit, the transponder unit decodes an interrogation signal it has received and generates a response signal. The transmission rate at which to transmit the response signal is monitored. If the result of the monitoring indicates that the transmission rate has reached a preset value, the response signal is transmitted from the DME ground apparatus. If the result of the monitoring indicates that the transmission rate has not reached a preset value, squitter pulses are transmitted from the DME ground apparatus.

Abstract: A transmitting apparatus comprises a generator for generating a pulse signal having a waveform approximated to the Gaussian error function at a prescribed timing, a transmitter for power-amplifying a pulse signal generated by the generator, and transmitting the amplified pulse signal, an evaluator for extracting a pulse waveform part from the power-amplified pulse signal, comparing the extracted pulse waveform part with an ideal waveform so as to obtain an error amount between the pulse waveform part and the ideal waveform, and evaluating whether or not the error amount is within a prescribed error range, and a controller for causing the generator to subject the waveform of the pulse signal to correction in such a manner that the error amount becomes smaller each time an evaluation result of the evaluator is that the error amount is out of the prescribed error range.