Abstract: Systems and methods for automatically disabling the TCAS Broadcast when aircraft join up in formation. A Traffic Collision Avoidance System (TCAS) determines if the aircraft is approaching formation flight with other aircraft or flying in formation with other aircraft and disables a TCAS interrogation signal if the aircraft is determined to be approaching a formation or flying in formation. The TCAS receives TCAS interrogation signals from one or more other aircraft and receives aircraft configuration information from one or more other aircraft systems. The TCAS determines the aircraft is approaching formation flight or flying in formation based on the received TCAS interrogation signals, a mode of TCAS operation, and/or the received aircraft configuration information. The TCAS also automatically switches into Traffic Advisory Only mode if the aircraft is determined to be approaching formation flight or flying in formation.

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: A system is delineated comprising a TCAS receiver having one or more filters, one or more amplifiers and one or more A/D converters, the one or more A/D converters for digitizing analog data into digital data for decoding one or more of an ADS-B message and a TIS-B message; and circuitry for receiving the digital data and decoding the one or more of an ADS-B message and a TIS-B message, wherein the circuitry includes two or more paths for the decoding.

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: Systems and methods for avoiding runway collisions. In a disclosed embodiment of the invention, a collision avoidance system includes a position-sensing device that is operable to determine a position of the aircraft, and a communications system operable to support two-way communications between the aircraft and other similarly configured aircraft. A collision avoidance processor is coupled to the position-sensing device and the communications system that is configured to generate a message if the aircraft moves into a restricted zone positioned proximate to the airport.

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: A directional receiver is provided for an aircraft collision avoidance system. The receiver may include input channels that are configured to receive uncompressed linear analog signals from antenna elements that are arranged within a predetermined antenna element geometry. The receiver may further include Analog to Digital (A/D) converter modules, a quadrature converter module and a combiner module. The A/D converter modules can convert each of the analog signals to uncompressed linear digital data and output separate digital data streams that correspond to each of the input channels. The quadrature converter module can mix the digital data streams with corresponding digital reference signals to produce digital In-phase (I) and Quadrature (Q) streams.

Abstract: A method for asynchronously transmitting bursts of data from a communications terminal to a burst radar transceiver is disclosed. The burst radar can transmit a plurality of bursts, each separated by an inter-burst interval. An inter-burst interval length of the burst radar transceiver can be established. A burst of data at the communications terminal can be formed having a terminal burst interval length less than half the inter-burst interval of the burst radar transceiver. The burst of data can be transmitted a plurality of times from the communications terminal to the burst radar transceiver.

Abstract: An active antenna is provided that includes an antenna element for transmitting RF transmit signals at a predetermined effective radiated power (ERP). An antenna module is configured to be mounted to an aircraft, with the antenna element being mounted to the antenna module. A connector module is provided at the antenna module and is configured to be coupled to a communications link and receive electrical transmit signals from the communications link. A transmit path is provided within the antenna module and extends between the antenna element and the connector module. A power amplifier is provided on the antenna module along the transmit path. The power amplifier increases a power level of the electrical transmit signals, received from the communications link, by a predetermined amount sufficient to drive the antenna element to transmit the RF transmit signals at the predetermined ERP.

Abstract: The present invention is a combined aircraft TCAS/Transponder with common antenna system and transmitter. Common TCAS/Transponder multi-monopole top and bottom antennas may be connected to a top and bottom antenna modules, the top and bottom antenna modules being electrically coupled to the combined TCAS/Transponder transmitter/receiver block through connection lines.

Abstract: A method and system for using a single transceiver to correlate radar position data with target identification data. Two transceivers, operating in round trip delay mode, can be used to provide two possible positions for a given target when radar coverage is lost or unavailable. Three transceivers can be used to provide actual position of a given target using round trip delay data only.

Abstract: A system and method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system, wherein the method includes the steps of providing a standard ADS-B transmitter and encoder, a phase modulator including a digital synthesizer, radio-frequency electronics, antennas, and a radar transceiver; synthesizing digital-based band signals from the ADS-B transmitter with additional random phase modulation using the digital synthesizer; using the antennas to both transmit and receive signals; and estimating angles-of-arrival for every target in a field-of-view. The method may include the steps of demodulating the signals received by the antennas, providing a digital signal processor, and performing matched filtering on received signals. The method may also include the step of estimating a target range of identified targets using the digital signal processor.

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: An interrogation transmission method of a secondary surveillance radar compares prediction angle ranges for transmitting interrogations with a beam-width of an antenna, and transmits the interrogations at every roll-call period if the prediction angle ranges for transmitting interrogations are narrower than the beam-width of the antenna. In contrast, if the prediction angle ranges for transmitting the interrogations are wider than the beam-width of the antenna, the radar respectively sets a period to transmit the interrogations and a period not to transmit the interrogations until responses can be received, and transmits interrogations at every roll-call period after the responses can be received (even if a receiving error or downlink occurs).

Abstract: A panoramic warning system for helicopters, for the purpose of detecting obstacles and the proximity of the ground by using a plurality of radar sensors connected to the fuselage structure of the helicopter and which operate on varying wavelengths, the signals of which, representing range information, which are provided with an individual identifier, are compared in a central identification-and-evaluation unit with predetermined warning thresholds and after the assignment to corresponding scan sectors are caused to be displayed on at least one cockpit display.

Abstract: There is provided an avionics system that provides several avionics functions within a single LRU. In one embodiment, the system comprises a software-configurable RF assembly, one or more processor assemblies that are configured to provide multiple TAWS/TCAS/Mode S/ADS-B/ATC functions, interfaces to allow connections to aircraft electronics and data loaders, and multipurpose antennas. In one embodiment, a common processor architecture allows generic avionics processors to be configured to operate a number of TAWS/TCAS/Mode S/ADS-B/ATC functions without the need for multiple LRUs, and software-defined RF functions allow RF circuitry that interfaces to the processors to handle current and future communication needs.

Abstract: A system and method of using a standard ADS-B transmitter and encoder to identify targets to provide a collision avoidance system, wherein the method includes the steps of providing a standard ADS-B transmitter and encoder, a phase modulator including a digital synthesizer, radio-frequency electronics, antennas, and a radar transceiver; synthesizing digital-based band signals from the ADS-B transmitter with additional random phase modulation using the digital synthesizer; using the antennas to both transmit and receive signals; and estimating angles-of-arrival for every target in a field-of-view. The method may include the steps of demodulating the signals received by the antennas, providing a digital signal processor, and performing matched filtering on received signals. The method may also include the step of estimating a target range of identified targets using the digital signal processor.

Abstract: An apparatus for processing pulses in ATCRBS/Mode S interrogations includes an antenna for receiving a radio frequency interrogation signal. The radio frequency interrogation signal is downconverted by a downconverter to an intermediate frequency signal. The intermediate frequency signal is converted to a digitized interrogation signal by an analog-to-digital converter. A processing unit, coupled to the analog-to-digital converter, detects a pulse peak in the digitized interrogation signal using a moving threshold to locate the peak pulse between a first fixed threshold and a second fixed threshold.

Abstract: A direction finding antenna system for determining the relative bearing of a second aircraft from a first aircraft in conjunction with a Traffic Alert Collision Avoidance System (TCAS). 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 TCAS interrogations, receive TCAS replies, and process the TCAS replies to determine the relative bearing of the second aircraft from the first aircraft.

Abstract: A transmitter provides a plurality of output signals. The transmitter includes a processor, a modulator, a first circuit, and a second circuit. The modulator provides a modulated signal responsive to the processor. The modulated signal includes an amplitude modulated radio frequency for transmitting a pulse. The first circuit provides a first output signal, responsive to and with higher power than the modulated signal. The first output signal has a first phase during transmitting of the pulse. The second circuit provides a second output signal, responsive to and with higher power than the modulated signal. The second output signal has a second phase during transmitting of the pulse. The second phase is controlled by the second circuit in accordance with the first phase, the second phase, and indicia of a third phase provided by the processor.

Abstract: An apparatus for processing pulses in ATCRBS/Mode S interrogations includes an antenna for receiving a radio frequency interrogation signal. The radio frequency interrogation signal is downconverted by a downconverter to an intermediate frequency signal. The intermediate frequency signal is converted to a digitized interrogation signal by an analog-to-digital converter. A processing unit, coupled to the analog-to-digital converter, detects a pulse peak in the digitized interrogation signal using a moving threshold to locate the peak pulse between a first fixed threshold and a second fixed threshold.

Abstract: A method and system for using a single transceiver to correlate radar position data with target identification data. Two transceivers, operating in round trip delay mode, can be used to provide two possible positions for a given target when radar coverage is lost or unavailable. Three transceivers can be used to provide actual position of a given target using round trip delay data only.

Abstract: A station for assisting the control of an aircraft includes warning means (5) adapted to deliver an alert for avoiding a later collision when there is a risk that the predicted flight trajectory of the aircraft crosses any predicted flight path of another aircraft. An arrangement (4) is adapted to determine whether the aircraft carrying said station is within an airspace volume with defined geometrical dimensions and time of appearance and disappearance or not and make the function of the warning means dependent upon this comparison by, when located in said airspace volume, deactivating said warning means with respect to other aircraft of a predefined identity, and when not located in said airspace volume, activate or keep the function of said warning means activated with respect to aircraft of said predefined identity. (FIG. 1).

Abstract: The present invention relates to an avoidance system and method for directing an aircraft away from an exclusion zone. The exclusion zone may be any three dimensional space for example about a building or city. The avoidance system uses a constant signal from a ground based transmitter and an aircraft's receiver which receives and processes the signal and activates the avoidance system by engaging the flight director system or autopilot to steer away from the exclusion zone.

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

Abstract: A system for transmitting into a shared medium includes a processor, a transmitter, and a receiver. The processor is coupled to the transmitter for transmitting in a manner, at a time, and at a power level as directed by the processor. The processor determines from cooperation with the receiver the number of transmitters expected to be sharing the medium at a future time when transmitting is desired; prescribes a total power for a plurality of transmissions; and prescribes a maximum power for individual transmissions of various types.

Abstract: A traffic alert and collision and avoidance system (TCAS) is disclosed. The TCAS comprises a first transponder and a first interrogator associated with a first aircraft. The first transponder sends an interrogation request. The TCAS also comprises a second transponder associated with a second aircraft. The second transponder responds to the interrogation request. The response comprises enhanced surveillance data that was asked for in the request.

Abstract: A secondary surveillance radar system for use in surveillance of an airspace, which reliably achieves surveillance of the airspace even when an aircraft including a mode S transponder and an aircraft including an ATCRBS transponder are both located in the airspace, wherein both of a time interval between time when transmission of an all-call interrogation signal specific for mode S is completed and time when the transmission of an all-call interrogation signal specific for mode A is started and a time interval between time when transmission of the all-call interrogation signal specific for mode S is completed and time when transmission of an all-call interrogation signal specific for mode C is started is varied in units of one all-call time period.

Abstract: A radar transponder is provided that synchronizes the encoding of repeated radar pulses using an envelope detector to detect the envelope of received radar pulse signals. An edge detector detects the pulse edges in the envelope so that code words may be multiplied with the received radar pulse signals synchronously with the detected pulse edges to provide an encoded pulse train that may be transmitted to a radar interrogator.

Abstract: A system for autonomously keeping an aircraft's station in a formation flight of a plurality of aircraft includes a navigation system configured to determine a position of an aircraft. A data link is configured to allow the aircraft to communicate data with at least one other aircraft in the formation flight of the plurality of aircraft. A sensor is configured to detect a presence of another aircraft within a predetermined distance of the aircraft. A processor is configured to provide control signals to the aircraft's autoflight system to keep the aircraft at a predetermined station relative to the other of the plurality of aircraft in the formation flight.

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.

Abstract: An apparatus and method for combining the functionality of multiple airborne traffic surveillance systems that operate in the L-band frequency range. The apparatus and method combine the functionality of both a Traffic Alert Collision Avoidance System (TCAS) and a Mode-Select (Mode-S) transponder in an integrated L-band traffic surveillance apparatus having a single processor that is embodied in a single Line Replaceable Unit.

Abstract: A surveillance system for an aircraft includes a first antenna comprising a four radiating element antenna. The first antenna is configured for electrical coupling to a first air traffic control transponder and a first traffic alert and collision avoidance system, and a second antenna comprises a single element antenna configured for electrical coupling to a second air traffic control transponder. The surveillance system also comprises a second antenna comprising a single radiating element antenna configured for electrical coupling to a second air traffic control transponder. The surveillance system also comprises a first mounting interface configured for coupling the first antenna to the aircraft. The surveillance system also comprises a second mounting interface configured for coupling a second antenna to the aircraft. The mounting interface of the first antenna has a size and a shape corresponding to a size and shape of the mounting interface of the second antenna.

Abstract: A passive airborne mounted collision warning system suitable for light aircraft that enables an observer aircraft to determine the position of a nearby transponder-equipped target aircraft. The transponder-equipped target aircraft transmits replies responsive to interrogation signals from rotating secondary surveillance radars (SSR). In an embodiment of the invention, position of the target aircraft is determined based on the known position of the observer aircraft obtained e.g. via satellite navigation means such as GPS, the position of the SSR, and the bearing of the target aircraft measured by a direction finding antenna. The direction-finding antenna elements and the GPS receiver components are included in a device that is externally mounted on the observer aircraft. The data from the device is connected to a portable computer for processing and presentation to the pilot to alert him of the position of the target aircraft for avoiding collisions.

Abstract: An improved system and methods for correlating an interrogation-based air traffic surveillance intruder, such as an Traffic alert and Collision Avoidance System (TCAS) intruder, and a GPS-based air traffic surveillance target, such as an Automatic Dependent Surveillance Broadcast (ADS-B) target to minimize or eliminate the display of two symbols for the same intruder/target on the CDTI of an aircraft. The method comprises the steps of receiving ADS-B data at a processing unit and calculating select component deltas for the ADS-B data versus an entry in a TCAS intruder file. Progressive weights are assigned to the deltas and the progressive weights are summed, resulting in a total confidence score. Total confidence scores of ADS-B target and TCAS intruder pairs are compared to determine correlation between the ADS-B target and the TCAS intruders.

Abstract: A display system is disclosed for displaying air traffic symbology from a plurality of different types of air traffic surveillance systems on a single monitor. A display device includes a processor for generating display symbology from TCAS, SKE and ADS-B information, and a monitor for displaying the generated symbology in a uniform format.

Abstract: An airborne radar system is disclosed. The airborne radar system comprises a radar antenna, radar circuitry coupled to the radar antenna, and a runway database comprising runway location information. The airborne radar system also comprises a processing device retrieving from the runway database, runway location information for a runway being approached by an aircraft, based on the location of the aircraft, and directing a radar beam defined by a polygon which represents the runway and which is derived from the runway information, the processing device determining whether there are any obstacles on the runway.

Abstract: Receiving a message including bits corresponding to an identifier, the identifier including a unique address for a aircraft transponder, extracting the unique address from the identifier, comparing the unique address to a set of predetermined addresses, changing selected ones of the identifier bits when the unique address is not one of the set of predetermined addresses, wherein the changing of the identifier bits changes a value of the unique address in the identifier, re-comparing the updated unique address to the set of predetermined addresses and processing the message when the unique address matches one of the set of predetermined addresses.

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: A transponder lock provides allows an aircraft transponder to continue transmitting an alerting code for the duration of an emergency. The transponder lock thereby enables the aircraft transponder to continue to provide crucial information to ground tracking stations. Installation of the transponder lock results in very little aircraft downtime because the transponder lock connects in-line with existing aircraft wiring.

Abstract: A super resolution processor/receiver to discriminate superimposed secondary surveillance radar (Mode S, Mode A/C) replies and squitter that uses frequency-domain analysis to suppress interference between replies. In particular, the processor/receiver uses a spectral super-resolution method to estimate carriers of reply signals (every reply has a carrier that could be slightly different from the others). These frequency analyses, applied with particular timing referring to the signal that effectively carried the information, allow to estimate the information on SSR Mode S/Mode A/C replies.

Abstract: A super resolution processor/receiver to discriminate superimposed secondary surveillance radar (Mode S, Mode A/C) replies and squitter that uses frequency-domain analysis to suppress interference between replies. In particular, the processor/receiver uses a spectral super-resolution method to estimate carriers of reply signals (every reply has a carrier that could be slightly different from the others). These frequency analyses, applied with particular timing referring to the signal that effectively carried the information, allow to estimate the information on SSR Mode S/Mode A/C replies.

Abstract: A ground-based CFIT warning system provides pilots with CFIT alerts. The system is based upon a ground-based tracking system, which provides surveillance of aircraft, such as the AirScene™ multilateration system manufactured by Rannoch Corporation of Alexandria, Va. The system monitors both horizontal and vertical positions of aircraft. When an aircraft has been determined to be operating below safe altitudes, or too close to obstructions, the pilot is provided with a warning. The warning may be delivered via the pilot's voice communications and/or a data link or the like.

Abstract: An algorithm for improved tracking of Air Traffic Control Radar Beacon System transponders is disclosed. The algorithm can be combined with a system that includes an interrogator which transmits an interrogation signal to an associated vehicle transponder at a first frequency, preferably 1030 MHZ in accordance with FAA regulations, and a receiver array which receives the transponder reply signal transmitted by the transponder at a second frequency, preferably 1090 MHZ in accordance with FAA regulations. An angle of arrival processor calculates an angle of the received reply signal, and a position processor calculates the vehicle position based on at least the received angle data.

Abstract: A display system is disclosed for displaying air traffic symbology from a plurality of different types of air traffic surveillance systems on a single monitor. A display device includes a processor for generating display symbology from TCAS, SKE and ADS-B information, and a monitor for displaying the generated symbology in a uniform format.

Abstract: An airborne collision avoidance system includes a receiver stage constructed and arranged to detect (a) at a first radio frequency, first interrogation signals, and first collision resolution advisory (RA) signals transmitted from other nearby aircraft, and (b) at a second radio frequency, first acquisition signals including position information with respect to the nearby aircraft, and first reply signals from the nearby aircraft. A transmitter stage is constructed to produce (a) at the first radio frequency, second interrogation signals and second collision RA signals, and (b) at the second radio frequency, second acquisition signals including position information with respect to the given aircraft, and second reply signals from the given aircraft in response to the first interrogation signals. Tracking and collision avoidance information derived by a system processor from the detected first acquisition and first RA signals is shown on a cockpit display.

Abstract: A method of transmission between two elements chosen from a terminal and a transponder, each element including an oscillating circuit, a modulator and a demodulator, including simultaneously performing a transmission in amplitude modulation of a signal transmitted from a first to a second element and a transmission of a signal from the second to the first element adapted to being submitted to a phase demodulation in the latter, and wherein the amplitude modulation rate is smaller than 100%.

Abstract: A method of avoiding conversion spurs in a multi-conversion radio frequency receiver having a first local oscillator, an intermediate frequency filter and a second local oscillator in series generates, based on a center frequency for the intermediate frequency filter, a table of problem frequencies of the first local oscillator relative to a frequency of the second local oscillator which produce harmonic mixing products within the bandwidth of the intermediate frequency filter versus corresponding frequency offsets for the second local oscillator which retune the frequency of the second local oscillator so the harmonic mixing products are moved outside the bandwidth of the intermediate frequency filter.

Abstract: A system having replaceable subsystems is operable in a certified configuration after installation of a replacement subsystem. The system includes several subsystems each installed at an interface. For each subsystem, the interface includes memory having a description of the operating environment for that subsystem. The memory stores modules each having a signature, for example, a cyclic redundancy code (CRC). After installation of a replacement subsystem, a processor in the subsystem checks a list of signatures. Each signature corresponds to a module that is certified for use by an application program of the subsystem. If a listed signature corresponds to a module that is available in the memory, is desirable to be used, and the subsystem is not presently configured to use such a module, the subsystem reads the module, integrates the data of the module into an operating configuration, and operates thereafter in accordance with the updated operating configuration.

Abstract: A surveillance and collision avoidance system provides a presentation of situational awareness information for display that includes a compound symbol for each target spaced at a distance and bearing relative to a host symbol. The target compound symbol includes indicia of (a) whether the target is airborne or on the ground; (b) whether the target is a civil aircraft, a military aircraft identified as a formation member with the host aircraft, or a military aircraft not identified as a formation member with the host aircraft; (c) whether a ground track for the target is unknown, known by passive surveillance, or known by active surveillance; (d) for civil aircraft, whether the target is the subject of no advisory, a traffic advisory, or a resolution advisory; and (e) for a military aircraft, whether the target is the subject of no encroachment advisory, an unintended encroachment advisory, or an intended encroachment advisory. Subsystems selectively use an active or a passive mode of surveillance.