Abstract: In one example, a radar circuit uses computer processing circuitry for processing data corresponding to reflection signals via a sparse array. Output data indicative of signal magnitude associated with the reflection signals is generated, and then angle-of-arrival information is discerned therefrom by (e.g., iteratively): correlating the output data with at least one spatial frequency support vector indicative of a correlation peak for the output data; generating upper-side and lower-side support vectors which are neighbors along the spatial frequency spectrum for said at least one spatial frequency support vector, and providing, via a correlation of the upper-side and lower-side support vectors and said at least one spatial frequency support vector, at least one new vector that is more refined along the spatial frequency spectrum for said at least one spatial frequency support vector.

Abstract: A density of Mode S interrogations and responses in the environment covered by a secondary radar is characterized according to the following steps: a first step wherein the radar: detects and locates Mode S targets by way of their synchronous responses to the interrogations emitted by the radar; detects asynchronous responses emitted by the Mode S targets, and not elicited by the radar; for each target, associates its asynchronous responses with its synchronous response to the radar; a second step wherein the radar: based on the association, determines the response rate of each target by counting the number of synchronous and asynchronous responses received from the target per given time period; with the environment being divided into elementary space cells, determines the response rate per cell by counting the number of synchronous and asynchronous responses received by each target in each cell, the rate characterizing the density of Mode S interrogations per cell.

Abstract: A method for locating a portable radio unit (TF) within a predetermined area (AB, IB) of a vehicle (FZ) has the following steps. A first radio signal (FS1) is transmitted from a vehicle-based position (PO1) outside the vehicle. Further, a second radio signal (FS2) is transmitted from a vehicle-based position (PO2) inside the vehicle. Values (R1, R2) of the respective measured reception field strengths of the first and second radio signals at the location (OF) of the portable radio unit or a value derived therefrom is/are received. Finally, the location (OF) of the portable radio unit is ascertained on the basis of a comparison of the values of the respective measured reception field strengths. In this manner, a simple and reliable way of locating a portable radio unit is also made possible using radio-frequency radio signals.

Abstract: An each pattern is provided a reception pathway, the method uses the synchronous replies and the asynchronous replies, unsolicited of Fruit type, transmitted by targets present in the aerial environment of the radar and detected over a given number of antenna revolutions. At each detection of a reply the value of its off-aim in bearing and the value of relative power received on each of the pathways are calculated as is its elevation by extrapolation with the synchronous detections close to the same target and associated with the detection. The values obtained over the given number of revolutions are stored, the measured patterns being sampled on the basis of the stored values.

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

Abstract: A method for ascertaining positional data describing a position of a motor vehicle relative to a stationary charging device as a destination. At the charging device end, a plurality of electromagnetic transmission signals are emitted from respectively different transmitting positions that are arranged in a transmitting position pattern and have respectively at least one signal characteristic that can be differentiated by the motor vehicle during reception. After which, for each reception signal received, signal strength data that describe its reception strength are produced, and the positional data are determined from the data, taking into consideration transmitter information describing the transmitting position pattern and an assignment of the transmitting positions to the signal characteristics.

Abstract: An ultra-broadband coherent radar transponder for precision tracking, and in particular a transponder arrangement having an antenna, receiver, control logic, delay, and transmitter components arranged to coherently amplify, delay and repeat back a reference signal to be utilized by a microwave radar system for high fidelity tracking.

Abstract: A method and system for providing situational awareness in a vehicle. The method and system include receiving environmental sensor data and vehicle performance sensor data. The method and system also include compiling the environmental sensor data and the vehicle performance data. The method and system additionally include determining one or more situational risks that are posed to the vehicle that occur within a surrounding environment of the vehicle based on the compiled environmental sensor data and the vehicle performance data. The method and system further include generating one or more projected graphical objects that represent the one or more situational risks that are determined to be posed to the vehicle.

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

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

Abstract: Methods for determining a range rate of a backscatter transponder and readers implementing the methods are described. The reader transmits a continuous wave signal and receives a modulated reflected response signal from the transponder, mixes the modulated reflected response signal with the carrier frequency to produce a downconverted signal, bandpass filters the downconverted signal to pass a bandpass filtered signal containing at least the modulation frequency, applies a non-linear amplitude transfer function to produce a modulation-suppressed signal, and measures the frequency of the modulation-suppressed signal and determines the range rate from the measured frequency.

Abstract: Methods and an appropriately setup communication unit for positioning in vehicle-to-surroundings communication are described, wherein the method involves a first sensor (S1) of a first communication subscriber using a transmission and reception unit to emit a challenge pulse, to which a transmission and reception unit of a second sensor (S2) of a second communication subscriber responds with a response pulse. The response pulse is received and evaluated by the first sensor (S1) and positioning is performed. In order to achieve reliable cooperative sensor communication, the transmission and reception units of the first and second sensors (S1, S2) use a frequency band (SCH2) which is reserved for vehicle-oriented safety applications.

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

Abstract: An improved system and method for monitoring objects, people, animals, or places uses a passive Modulating Reflector (MR) tag where a characteristic of an antenna is modified according to a time-varying pattern by a modulating network thereby causing the reflective characteristics of the antenna to vary in accordance with the time-varying pattern. When an interrogator transmits an RF waveform that impinges on the antenna, the return signal reflecting off the antenna is modulated in accordance with the time-varying pattern allowing a remote receiver to demodulate information from the modulated return signal. The antenna is embedded in a dielectric material. The MR tag can be used with a wide variety of tag-interrogator configurations employing monostatic and/or bistatic radar techniques to allow monitoring, locating, and/or tracking of objects, people, animals, or place with which MR tags are associated.

Abstract: Various techniques are described relating to verifying a distance between devices. A distance between two devices may be verified by requiring one of the devices to take one or more actions that generate a result that is only possible if the device is at most a given distance from the other device. In some aspects verified ranging is accomplished through the use of a ranging signal and a responsive signal. In some aspects the ranging signal may comprise a random, pseudorandom, or deterministic sequence. A responding device may operate on a ranging signal in accordance with a known function to generate a responsive signal. A ranging device also may perform operations to determine the likelihood that a responding device properly operated on a ranging signal that the ranging device transmitted to the responding device.

Abstract: Active RFID technologies are used to tag assets and people within buildings or open areas, such as parking lots or military bases; and to identify, preferably within a few meters, the real-time location (RTL) of the tag, i.e. to create a real-time location system, known as an RTLS. A novel and complex algorithm is provided that combines signal strength computations with factors that incorporate physical realities, such as walls and floors, to determine a tag's real-time location more accurately.

Abstract: A process and a device for detecting aircrafts circulating in an air space surrounding an airplane is disclosed. The device (1A) comprises means (2, 3) for detecting an aircraft circulating in the air space surrounding the airplane and, in case of a detection, for determining a first position and a second position of the aircraft with respect to the airplane, and means (8A) for comparing said first and second positions so as to check whether they match.

Abstract: An aircraft avian radar is implemented using an existing aircraft transponder, Mode S, or TCAS installation as the radar transmitter. To eliminate self jamming of low level avian target signals by high level transmitter signals, the ending period of the transmission signal is digitized and cross correlated with the ending period of reflected avian target signals received after the transmission signal has ended. In a first implementation, the current transponder antenna is used for both transmission and reception. In a second implementation, an external receive only antenna is mounted in a position that maximizes the transmit antenna to receive antenna isolation. In a third implementation, a signal canceller and sample of the transmit signal are used to cancel or null out as much transmit signal as possible that couples directly to the receive antenna.

Abstract: In certain embodiments, a method includes receiving first track information comprising data for a particular aircraft track. The method further includes receiving a first radar plot comprising first location information corresponding to first aircraft identification information and first location information corresponding to second aircraft identification information. The method further includes associating the first aircraft identification information with the particular aircraft track. The method further includes accessing historical association information comprising a first association history variable corresponding to one or more previous associations between the first aircraft identification information and the particular aircraft track and a second association history variable corresponding to one or more previous associations between the second aircraft identification information and the particular aircraft track.

Abstract: Systems and methods are delineated that may provide for a system for use in a merging and spacing application for an aircraft. An exemplary system may comprise a TCAS and a processor for executing the merging and spacing application using ADS-B data and data received by the aircraft in response to an interrogation of another aircraft from the TCAS. In a disclosed embodiment, a lead aircraft responds to the TCAS interrogation from a following aircraft to provide EHS heading and/or speed of the lead aircraft to the following aircraft, which uses the received EHS data as well as ADS-B data to determine merging and spacing control parameters for the following aircraft.

Abstract: An apparatus for measuring the relative direction of an incoming radio signal, the apparatus comprising at least first and second antennas, and comparison means for comparing the incoming radio signal as received at the first antenna with the incoming radio signal as received at the second antenna, and from the result of the comparison transmitting a measurement of the relative direction.

Abstract: A system according to the invention detects location information of a vehicle by using a reflection strength change of an electromagnetic wave. The system incorporates a radiowave transmitter which emits a first radiowave, positional markers which generate unique reflection strengths and patterns of temporal changes in the reflection strength from the emitted first radiowave at respective absolute positions, a radiowave receiver which receives a second radiowave reflected by the positional marker and converts the second radiowave into a signal format for extracting location information to output the same, and a marker recognition device which obtains a location of the vehicle from the output of the radiowave receiver. Accordingly, a highly-precise location specification with a resolution smaller than or equal to 1 cm and a highly-reliable location specification which is not affected by slip and slide of the vehicle's wheels can be realized.

Abstract: A method is provided for mobile device enabled radar tags. A signal is transmitted to a radar tag. The radar tag detects the signal. The radar tag provides information. The information is received from the radar tag. A location of the radar tag is determined based on the information. The radar tag is identified based on the information. The identification of the radar tag, the location of the radar tag, and a time associated with determining the location of the radar tag are recorded as data in a database. The radar tag is evaluated based on accessing a plurality of recordings of the data in the database.

Abstract: Systems and methods for reducing radar target processing. The systems include a processor configured to receive a first input from a cooperative surveillance source and a second input from a radar device. The first input includes cooperative target information, the second input includes cooperative and non-cooperative target information, and the processor is configured to process the first and second inputs to remove cooperative target information from the second input based on the first input to generate a modified radar output for use by an output device. The methods include receiving a first input including cooperative target information from a cooperative surveillance source, receiving a second input including cooperative and non-cooperative target information from a radar device, processing the first and second inputs to remove cooperative target information from the second input based on the first input, and generating a modified radar output based on the processed first and second inputs.

Abstract: Provided is a secondary surveillance radar with an improved capability of eliminating an unnecessary Mode A/C target report, which includes a transmission unit transmitting interrogations, a reception unit receiving replies, from a transponder, corresponding respectively to the interrogations, and a signal processing unit generating a Mode S target report and a Mode A/C target report from the replies. The radar also includes a combiner generating a Mode S track and a Mode A/C track respectively from the Mode S and the Mode A/C reports, and then judging whether the Mode S report and the Mode A/C report are of the same target on the basis of the Mode S and the Mode A/C tracks. When the Mode S and the Mode A/C reports are of the same target, the combiner rejects the Mode A/C report.

Abstract: Methods and apparatuses are described that enable the automatic collection of maritime vessel location information within a global or regional framework by using a minimum network of vessels outfitted with non-intrusive AIS data collection systems. The network of vessels may comprise standard ships operating within their normal commercial or private tasks. By utilizing these non-specially tasked vessels and augmenting the received AIS reports with onboard radar/navigation information, accurate global or regional tracking information can be generated at a centralized location without incurring large costs.

Abstract: An interrogator that is to be incorporated in a communication system in which each of at least one transponder is operable, upon reception of a main carrier wave transmitted from the interrogator, to respond to the interrogator with a reflected wave that is generated by modulating the main carrier wave.

Abstract: Systems and methods for mapping a surface of a celestial body containing objects and terrain are provided. One system includes a Synthetic Aperture RADAR (SAR) module configured to capture a high-resolution image of the terrain of at least a portion of the surface and a map module configured to store map data representing the portion of the surface. The system also includes a fusion module configured to combine the high-resolution image and the map data to generate a high-resolution map of the portion of the surface. A method includes orbiting the celestial body, capturing, via the SAR module, a high-resolution image during each orbit, and fusing the captured high-resolution image with a low-resolution map of the surface to generate a high-resolution map of the surface. A computer-readable medium for storing instructions that cause a processor to perform the above method is also provided.

Abstract: A device and a method for triggering at least one deceleration device and/or one output-determining actuator element of a vehicle propulsion system, in particular for automatic longitudinal vehicle regulation, a first surroundings sensing device being provided, which delivers longitudinal value-optimized measured values, a second surroundings sensing device being provided, which delivers object lateral dimension-optimized measuring values, and an analyzer device being provided, which receives the output signals of the first and second surroundings sensing devices and the measured values of the first and second surroundings sensing devices being used for object identification. The device and the method are furthermore suitable for initiating or performing vehicle deceleration for collision avoidance or for alleviating the severity of a collision.

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: There are presented various approaches to monitor performance of RF systems and circuitry such as those used in aircraft transponders. Such monitoring may be designed to verify operational performance of transponders as set forth by FAA regulations, or may be used to periodically or continually monitor integrity of transponder performance. Data may be collected by such periodic or continual monitoring, and may be analyzed to identify potentially troublesome trends in transponder performance, allowing early intervention or repair, if warranted.

Abstract: A system and method for target classification for an aircraft surveillance radar is provided. In one implementation, the track classifier provides tracks with an updated probability value based on its likelihood to conform to aircraft and non-aircraft target behavior. The track classifier identifies false tracks that may arise from weather and biological targets, and can detect aircrafts lacking Secondary Surveillance Radar (SSR) data. Various features and combinations of features are evaluated using a proposed clustering performance index (CPI) and used to discriminate between aircrafts and false tracks.

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: This equipment is of the TCAS type. In order to improve its integrity and the reliability of its measurements, its computing unit is provided with a cross-checking function carrying out the comparison between two values of a same parameter, for example a relative distance with respect to an intruder, one of them generated by its own estimating means and the other communicated by another TCAS equipment installed on the intruding aircraft and generating a discordance alarm in the case of the observed difference exceeding a tolerance threshold. The computing unit is provided with fault locating means locating the aircraft whose TCAS is faulty when in the presence of several intruding aircraft, by examining the observed differences in pairs of values of a same parameter established for each intruding aircraft.

Abstract: The invention relates to a system, device, and method for using radar signals to measure the distance (h) to a surface from said device, the device comprising a transmitter and a transmitting antenna for transmitting radar signals, and a receiver and a receiving antenna for receiving a radar signal. The device may also comprise a first additional reflecting object separate from the receiving antenna, which additional reflector is designed so as to introduce a first predetermined alteration in radar signals upon reflection, with the device being equipped with means to differ between received signals with and without said predetermined alteration. The first predetermined alteration introduced by the first separate reflector can be, for example, a modulation shift or a shift in the polarization of the signal. In a typical embodiment the additional reflector is located close to the radar unit creating a double transition from radar unit to the surface.

Abstract: An improved system and method for monitoring objects, people, animals, or places uses a passive Modulating Reflector (MR) tag where an antenna is alternately short and open circuited according to a time-varying pattern by a modulating network thereby causing the reflective characteristics of the antenna to vary in accordance with the time-varying pattern. When an interrogator transmits an RF waveform that impinges on the antenna, the return signal reflecting off the antenna is modulated in accordance with the time-varying pattern allowing a remote receiver to demodulate information from the modulated return signal. The MR tag can be used with a wide variety of tag-interrogator configurations employing monostatic and/or bistatic radar techniques to allow monitoring, locating, and/or tracking of objects, people, animals, or place with which MR tags are associated.

Abstract: Systems and methods for alerting surrounding aircraft if a ground-based unit is a threat. One example system is located on a ground-based unit. The system includes a position sensor that senses position of the ground-based unit, a memory that stores predefined threat zone information, a transmitter that transmits a predefined transponder signal, and a processor in data communication with the position sensor, the memory, and the transmitter. The processor instructs the transmitter to transmit the transponder signal based on the threat zone information and the sensed position of the ground-based unit.

Abstract: There are provided a differential processing unit which performs differential processing for a Mode S transponder transmission signal, an auto correlation arithmetic operation unit which performs an arithmetic operation of a degree of auto correlation between an increasing change rate and decreasing change rate of a power level in the signal which has been subjected to the differential processing, a pulse regeneration unit which regenerates a pulse based on the degree of auto correlation, which has been obtained by the auto correlation arithmetic operation processing, a pulse phase locked loop unit which performs gate processing and phase locked processing for the regenerated pulse, and a pulse decoding unit which decodes the Mode S transponder transmission signal based on the pulse which has been subjected to the gate processing and the phase locked processing.

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: An apparatus for use in controlling a simulated target position in a millimeter wave, hardware-in-the-loop system includes a pair of horns and a conditioning circuit. The conditioning circuit is capable of generating a pair of output millimeter wave signals, each to be broadcast from a respective one of the horns, the output millimeter wave signals being out of phase by a predetermined amount, and capable of attenuating at least one of the output millimeter wave signals to control the position of the simulated target in a first and a second region. A method for use in controlling a simulated target position in a millimeter wave, hardware-in-the-loop system includes generating a pair of output millimeter wave signals that are out of phase by a predetermined amount; attenuating at least one of the output millimeter wave signals to control the position of the simulated target in a first and a second region; and broadcasting the millimeter wave signals.

Abstract: An apparatus for use in controlling a simulated target position in a millimeter wave, hardware-in-the-loop system includes a pair of horns and a conditioning circuit. The conditioning circuit is capable of generating a pair of output millimeter wave signals, each to be broadcast from a respective one of the horns, the output millimeter wave signals being out of phase by a predetermined amount, and capable of attenuating at least one of the output millimeter wave signals to control the position of the simulated target in a first and a second region. A method for use in controlling a simulated target position in a millimeter wave, hardware-in-the-loop system includes generating a pair of output millimeter wave signals that are out of phase by a predetermined amount; attenuating at least one of the output millimeter wave signals to control the position of the simulated target in a first and a second region; and broadcasting the millimeter wave signals.

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: 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 technique for boresighting an antenna mounted on a moving platform is described. The technique uses a concurrently moving calibration target. Target navigation data and platform navigation data are used to compensate for movement of the target and the platform. The antenna pointing direction is biased in a direction which provides a best signal quality, and the bias used to determine antenna boresight calibration factors. The boresight correction factors can be used for open loop pointing.

Abstract: A system and method for performing distance measurement using wireless signals. A time of flight calculation is enabled by an interrogating device that transmits an interrogation signal to a responding device, which returns a synchronized signal back to the interrogating device. The wireless signals between the interrogating device and the receiving device have a harmonic relationship. In one embodiment, a time shift of a received signal relative to a transmitted interrogation signal is determined based on a comparison of a first reference point on a signal representative of the transmitted interrogation signal and a second reference point on a signal representative of the received signal.

Abstract: A vehicle positioning and tracking radar system includes a rotating antenna with a pair of spatially separated transmit feeds for simultaneously transmitting a pair of frequency-modulated continuous-wave (FMCW) electromagnetic signals having a first polarisation and a pair of spatially separated receive feeds for receiving an electromagnetic signal having a second polarisation, wherein the first and second polarisations are different from one another, such that the transmit feed and receive feed at the rotating antenna are isolated from each other; and a coded modulated transponder receives transmit signals from the rotating antenna with the first polarization and transmits a receive signal to the rotating antenna with the second polarization.

Abstract: An interrogator with an antenna that allows information exchanges with multiple transponders in a shorter distance of communication, by securing an intensified and uniform electromagnetic energy concentrated on areas near antenna elements. The interrogator is furnished with a sleeve antenna that includes a monopole conductor of ¼ wavelength (free space wavelength) continuously connected to a core wire of a coaxial cable on one end thereof, and a feed point on the other end, in which the sleeve antenna is grounded at the feed point. The interrogator has a plurality of the transponders arrayed near the antenna, and a plurality of the antennas selected by RF signal selectors. The interrogator antenna allows movable body identification such as in a goods management system for identifying multiply arrayed goods.

Abstract: A guidance system for guiding each of several projectiles toward a moving target has a platform having a radar system for illuminating the target with a radar signal. Each projectile has a receiver for receiving the radar signal reflected from the target, a transponder for replying to Global Positioning System (GPS) like timing signals from several timing signal sources, and a data link transceiver for establishing a bidirectional data link to the platform. The data link carries the measured frequency shift of the radar signal reflected from the target as measured by the projectile. A computer on the platform computes a relative position of each projectile with respect to the target from tracking the moving target using the radar system and the reply signal from the transponder on each projectile. The data link sends guidance commands from the platform to each projectile to guide the projectile to the target.

Abstract: Separation determination systems for determining the separation between a base station and a transponder, whereby the base station includes an oscillating signal source, for generating a signal and a transmission device for broadcasting the signal. The transponder includes a receiving device, for receiving the signal from the base station, an oscillator, for generating a signal which is phase-coherent therewith and a transmission device for broadcasting the phase-coherent signal. The base station furthermore includes a receiver device, for receiving the phase-coherent signal from the transponder and a separation determination device for determining the distance between base station and transponder. The system and components may be improved whereby the oscillator in the transponder is energized with the received signal in order to generate a quasi-phase-coherent signal.

Abstract: A Mode-S transponder is provided for detecting synchronization phase reversal (SPR) signals. The transponder includes a receiver for receiving a Mode-S signal that contains a P6 pulse having a Mode-S data segment and an SPR signal therein. The transponder also includes a phase detector that detects a phase change between first and second states in the received Mode-S signal. The phase detector includes an SPR qualifier that determine whether, following a state change, the Mode-S signal remains at one of the first and second states for at least a predetermined minimum time sufficient to qualify as a detector enable signal.