Abstract: A test and measurement apparatus, system, and method for synchronizing an acquisition or triggering system to a specific burst of interest. The subject apparatus and method triggers on varying energy content of a signal qualified by time in the presence of high-frequency input signal bursts, by using an adjustable pulse width envelope detector, disposed in the signal path of the trigger circuitry, as a digital rectifier or to otherwise process and extract an envelope signal. An RF envelope probe having an analog envelope detector among other suitable components is disclosed. A method is implemented for isolating an interval of interest in a signal under test. An envelope detector circuit produces an envelope signal from the signal. Trigger circuitry receives the envelope signal from the envelope detector, and isolates the interval of interesting in the signal under test using the envelope signal.

Abstract: A device and method for three-dimensional positioning are provided. The three-dimensional positioning of a common reference point is determined by fusion of supplied measurements, taking into account a lever arm compensation between the reference point, a global navigation satellite system (GNSS) receiver antenna, at least one radar antenna, and an inertial measuring unit.

Abstract: A low visibility landing system is provided for guiding aircraft on landing approaches. The low visibility landing system may aid a pilot during landing in low visibility conditions such that an aircraft may descend to lower altitudes without visual contact with the runway than is possible with other landing systems. The system may use various navigational systems to produce a hybrid signal that may be more stable than individual signals of those navigational systems. The hybrid signal is compared to a predetermined landing approach plan to determine the deviation of the aircraft from the landing approach plan and to provide guidance to the pilot to get the aircraft back onto the landing approach plan. The system may also use multiple navigational systems to perform checks on an operation of a primary navigational system to ensure that the primary navigational system is operating accurately.

Abstract: In a method for aiding aircraft landing using a GPS and an MLS within the context of a computed axial approach, the method uses coordinates of an azimuth antenna and/or of an elevation antenna as a reference point for the computation of a position of the aircraft in a reference frame centered on the landing runway. This position of the aircraft is thereafter used to determine an angle of azimuth between a longitudinal axis of the landing runway and the aircraft.

Abstract: Disclosed is a method and device for detecting lateral dissymmetry of an aircraft. A control parameter determination unit is used to determine a current value of a control parameter representative of all roll control surfaces of the aircraft, and a control parameter comparison unit is used to compare the determined current value with a predetermined reference value. A current deflection angle of a lateral stick of the aircraft is also determined, and the determined current deflection angle is compared with a predetermined angle value. A visual alarm signal is output, when the current value of the roll control surfaces of the aircraft is greater than a predetermined reference value and the lateral stick is at a deflection angle that is greater than a predetermined angle value.

Abstract: The present invention is a method for obtaining a localizer deviation and a glide slope deviation for an aircraft. The method may include directing electromagnetic signals from a weather radar system of an aircraft towards a runway. The method may further include receiving return signals in response to the directed signals. The method may further include, based on the received return signals, determining an azimuth angle for the aircraft relative to the runway, determining an elevation angle for the aircraft relative to the runway, and determining a range for the aircraft relative to the runway. The method may further include based on the azimuth angle, the elevation angle, and the range, calculating the localizer deviation and the glide slope deviation for the aircraft.

Abstract: The subject of the invention is a method of aiding the piloting of an aircraft (3), which is intended to aid the piloting of the aircraft during an autonomous approach to a landing runway (P) for the purpose of landing, said aircraft comprising at least one locating means (10, 12), wherein: a) an estimated instant of arrival of the aircraft on the runway is determined; b) a prediction of the performance of said locating means of the aircraft at least at this instant of arrival is determined; and c) on the basis of said performance of the locating means and of characteristics of said approach, at least one minimum decision height (Hmin) corresponding to this instant of arrival is determined, above which the aircraft is protected from the risks of collision with the environment when it is guided automatically onto an approach axis (A) corresponding to said approach. The invention also relates to a device for implementing this method.

Abstract: A method for guiding the approach and landing of an aircraft is provided. The method involves receiving navigation information from the aircraft, receiving navigation information from an aircraft carrier, integrating the navigation information from the aircraft with the navigation information from the aircraft carrier to determine a relative velocity and a relative position between the aircraft and the aircraft carrier, and propagating the relative velocity and the relative position forward in time for navigation purposes.

Abstract: A landing-control device is provided having a new structure for carrying out landing control of an aircraft. A detecting unit 10 detects at least a relative altitude from a landing surface to an aircraft. A parameter-generating unit 20 is constructed by a neural network having a feedback loop which receives a detection value detected by the detecting unit 10 and outputs a landing-control parameter of the aircraft, an output of a first node among plural nodes constituting the neural network being input to a second node different from the first node. A controlling unit 30 controls the aircraft based on the control parameter output from the parameter-generating unit 20.

Abstract: A system for aiding the landing of an aircraft on a runway uses an angular vertical position of the aircraft and includes at least one landing aid radio. In a stand-alone manner, the position of the aircraft in latitude and longitude is determined, and the position of the threshold of the runway in latitude and longitude is determined. A computing unit corrects, on the basis of positions of the aircraft and of the threshold of the runway, the angular vertical position of the aircraft. The corrected angular vertical position is used to aid the landing of the aircraft.

Abstract: A method and device for carrying out switchover on a radio frequency landing system of an aircraft between a first input of a radio frequency receiver, which input is connected to a first antenna disposed on a lower part of the aircraft and receives a first signal, and a second input of the radio frequency receiver, which input is connected to a second antenna disposed on an upper part of the aircraft and receives a second signal. On initialization, switchover occurs to the input whose signal exhibits the highest level. After the initialization phase, a first value of a parameter, in relation to the aircraft, and a second value of this same parameter, in relation to the runway, are determined. The difference between these first and second values is computed, and switchover occurs to one of the first and second inputs as a function of this difference.

Abstract: A method and device for determining a vertical position cue of an aircraft while landing in the presence of a lateral alignment beam, which is emitted from the ground and provides an indication of the aircraft's lateral alignment with respect to a landing strip, may include detecting the lateral alignment beam with aircraft equipment. On the basis of cues relating to the detected lateral alignment beam and of predetermined cues, an axis of approach of the aircraft is determined. Additionally, the actual position and a preset position of the aircraft, which corresponds to the position the aircraft would have if it were on the approach axis, are determined. On the basis of the actual and preset positions of the aircraft, the vertical deviation of the aircraft, representing the vertical position cue, is computed.

Abstract: An aircraft on-board system for communicating with a ground-based radio transmitter forming a part of a Local Area Augmentation System for aiding in the navigation and landing of the aircraft, comprising a radio receiver adapted to receive signals, including identification signals identifying the Local Area Augmentation System, from the ground-based radio transmitter, a controller coupled to the radio receiver having an entry device for entering the channel number of a desired ground-based radio station and for tuning the on-board radio receiver to a desired frequency and further receiving from the radio signals, including the identification signals, and further having a signaling mechanism for providing to an operator of the aircraft on-board system a message including the identification of the ground-based radio station.

Abstract: The method allows switchover between a first input (5) of a radiofrequency receiver (4) of the radiofrequency landing system (1), which input is connected to a first antenna (2) disposed on a lower part of the aircraft and receives a first signal, and a second input (6) of the radiofrequency receiver (4), which input is connected to a second antenna (3) disposed on an upper part of the aircraft. On initialization, switchover occurs to the input (5, 6) whose signal exhibits the highest level, and, after the initialization phase, a first value of a parameter, in relation to the aircraft, and a second value of this same parameter, in relation to the runway, is determined, the difference between these first and second values is computed, and switchover occurs to one of the first and second inputs (5, 6), as a function of this difference, and, moreover, one hysteresis loop around the switching values is provided.

Abstract: A system and method for measuring and predicting information on the position of approaching aircraft are disclosed. The system features a processor, an interrogating antenna, a receiving antenna, and a data link. The processor schedules interrogations and suppression pulses. Both of the antennas and the data link are in signal communication with the processor. The interrogating antenna transmits interrogations to a plurality of approaching aircraft. At least some of the interrogations include suppression pulses. The receiving antenna comprises at least three fixed, broad azimuth, array elements. The receiving antenna receives replies from each of the plurality of approaching aircraft and communicates the replies to the processor. The processor determines a state for each of the plurality of approaching aircraft based on the replies. The data link communicates information on the state of each of the plurality of approaching aircraft from the processor.

Abstract: A computer generated pilot instruction system for providing spatial information to a pilot corresponding to the difference between the actual landing fight path and optimal landing flight path.

Abstract: The invention deals with a surveillance system for terrestrial navigational and landing systems, in which the navigational signals being transmitted for aeroplanes or other airborne objects by the navigational and airport landing systems are received and evaluated by a ground-based receiving and control facility. In this system: the receiving and control facility is equipped with a plurality of additional receiving stations; these additional receiving stations operate in the frequency range of the navigational signals; the additional receiving stations are arranged geographically distributed within the transmitting range of the navigational or airport landing system; the signals recorded by the additional receiving stations are forwarded to a central evaluating unit.

Abstract: System and methods for a ground based millimeter wave imaging system that provides real-time millimeter wave images of an airport to one or more aircraft from one or more ground stations (18). The system includes at least one millimeter wave transceiver (19) that is located in each one or more ground stations. Each at least one millimeter wave transceiver collects real-time millimeter wave images of the airport. At least one image processor (21) is operatively connected to the at least one millimeter wave transceiver, and processes the real-time millimeter wave images of the airport. At least one data link (22) allows communication of information between the one or more aircraft and the one or more ground station. The one or more ground stations transmit the processed realtime millimeter wave images to the one or more aircraft using the at least one link.

Abstract: The invention comprises a mulli-wave radar system for obtaining first target position information of a flying object by capturing and tracking the flying object from a maximum detection distance, a stereo-camera system for taking over the tracking of the flying object in the vicinity of a landing point by acquiring the first target position information of the flying object from the milli-wave radar system, and obtaining second target position information having higher precision than the first target position information, and a controller for managing the first target position information of the milli-wave radar system and the second target position information of the stereo-camera system, controlling the milli-wave radar system to capture and track the flying object to the vicinity of the landing point, and controlling the stereo-camera system to capture and track the flying object at the time of landing of the flying object.

Abstract: A window-passage detection system has a ground system comprising: a first course generator (3) for generating a horizontal DDM (Differential Depth of Modulation) pattern for defining a horizontal width (25) of a virtual window frame by emitting a first carrier signal and a first side-band signal from a pair of first transmission antennae (6a and 6b), a second course generator (4) for generating a vertical DDM pattern for defining a vertical width (26) of the virtual window frame by emitting a second carrier signal and a second side-band signal from a pair of second transmission antennae (7a and 7b), and a third course generator (5) for generating a longitudinal DDM pattern for defining a longitudinal position (27) of the virtual window frame by emitting a third carrier signal and a third side-band signal from a pair of third transmission antenna (8a and 8b). Pairs of the first to the third transmission antennae (6a to 8b) generate three orthogonal polarization planes.

Abstract: A microwave radio frequency landing system includes an aircraft borne transmitter/receiver (transceiver) and a ground unit. The ground unit comprises a dielectric material lens and a transponder module array. The transceiver transmits pulsed interrogation signals to the ground unit. The dielectric material lens focuses the pulsed signals onto the transponder module array. The transponder modules illuminated by the pulsed signals transmit continuous wave return signals to the aircraft. Each continuous wave return signal comprises four tones, which are used by the aircraft to determine azimuth and glide slope of the aircraft, carried on a microwave carrier. In each transponder module which receives the pulsed signals from the aircraft transceiver, the microwave carrier is phase inverted for the duration of each pulse of the pulsed signals. The phase inversions on the microwave carrier are used by the aircraft to determine the range, velocity and acceleration of the aircraft with respect to the ground unit.

Abstract: A carrier frequency modulating system and method for producing a modulated carrier frequency is disclosed. The system comprises a carrier frequency signal generator for producing a carrier frequency signal at a carrier frequency at an output thereof. The system further comprises a sequencer for producing a modulation signal at an output thereof. This modulation signal comprises a plurality of modulation signal portions separated by at least one null modulation signal portion having a corresponding time length. The system is provided with a modulator for producing a modulated carrier frequency signal at an output thereof. The modulator has a first input connected to the output of the carrier frequency signal generator for receiving the carrier frequency signal, and has a second input for receiving the modulation signal. The system further comprises a power supply unit for supplying electrical power to the carrier frequency signal generator.

Abstract: An MLS system comprising ground based equipment which includes a microwave signal transmitter arranged to feed microwave signals to radiator elements of an array antenna via phase shifter modules one of which is provided for each of the said elements, whereby the production of a scanned microwave signal beam is facilitated, signal monitor/detector means effective to provide a detected sample signal derived from the scanned beam, filter means responsive to the detected sample signals for providing a filtered signal derived in dependence upon effective sidelobe signals in the said beam, and comparator means responsive to the filtered signal for providing a transmitter shutdown signal when the filtered signal exceeds a predetermined threshold level for more than a predetermined time during a predetermined number of successive scans.

Abstract: A microwave locating system is provided for locating known features and distinguishing between different types of features. The locating system includes a plurality of modulated microwave power sources located on known features and radiating modulated microwave signals having modulated frequencies selected in accordance with the known features. A video detection sensor camera is located remote from the sources for sensing microwave signals within a field of view and providing location signals for each of the sources. The camera includes an array of receiver elements which provide narrow bandwidth filtering so as to identify received signals as one of a plurality of selected modulated frequencies. The locating system further provides an image of the location signals which distinguishes between different selected located features.

Abstract: A method and means for monitoring a Microwave Landing System (MLS) that provides statistical independence of the monitoring process from the MLS to insure the integrity of the MLS signal format. The r.f. signal transmissions are received by a monitor receiver and down converted to i.f. signals. The i.f. signals are decomposed into in-phase (I) and quadrature (Q) components. The I and Q components are applied to a digital signal processor that derives all synchronizing information from the I and Q components and that effectively reconstructs the complete MLS signal format from the I and Q components. The reconstructed signal format is compared with predetermined standards and an alarm is generated if the reconstructed signal format is out of tolerance. The integrity of the monitoring process is insured by periodically substituting i.f. signals that simulate the MLS signal format but that are out of tolerance.

Abstract: In contrast with conventional transmitting stations for a position locating system in which the main equipment and the standby equipment operate alternately and are monitored by checking the transmitted signal received from external sensors, the present invention monitors at least the standby equipment during inactive periods during which no signal is being transmitted. In a preferred embodiment, external sensors (FS, MF) are provided for monitoring both the main transmitter (TXM) and the main timing and control section TCS1) during transmission periods, a dummy load (DL) and an internal sensor (IS) is used for monitoring the standby transmitter (TXR) during non-transmission periods, internal monitoring information (MI) is used for monitoring the reserve timing and control section (TCS2) and the electronic antenna (EA), and the two monitor sections (MS1, MS2) contained in the monitor unit are used to monitor each other.

Abstract: A method for obtaining the far field pattern of a phased array MLS antenna using measurements by a monitor located in the near field of the MLS antenna. The near field pattern differs from the far field pattern because of the presence of phase error terms in the measured near field pattern. The method comprises computing the Fourier transform of the complex conjugates of the phase error term of the near field pattern and convolving that transform with the measured near field pattern to obtain the far field pattern.

Abstract: Apparatus, and a corresponding method, for generating navigational data to aid a pilot in landing or taxiing an aircraft in poor visibility conditions. Radio-frequency (rf) beacons at predetermined locations around an airport runway or taxiway are separately modulated to render them uniquely identifiable from the aircraft. A fixed array of receiving antennas on the aircraft has multiple, angularly spaced antenna beams that substantially overlap each other in coverage, such that a signal received from one of the beacons will in most cases be received in more than one adjacent receive beam. Signals received in each beam are processed by a fast Fourier transform module to separate signal components from the various beacons; then an interpolation process determines the arrival angles of the signals by comparing the amplitudes received in adjacent receive beams.

Abstract: A system for demodulating and decoding differential phase shift keying (DPSK) transmissions utilizes a bandpass filter, an analog to digital converter and a digital signal processor. Removal of the effects of unknown frequency component is achieved by applying a complex phase correction/rotation factor after DPSK demodulation. The actual phase of the complex signal is never computed directly. All of the processing from Rader decomposition through carrier tracking filter is performed on the complex values and therefore requires only multiplication and addition operations which can be performed at high speed in a microcomputer or in dedicated arithmetic hardware.

Abstract: It describes a Microwave Landing System wherein.The means for surveillance of the transmissions from the various MLS stations are centralized in a single central station which then commands the various MLS stations. The connection between the central station and the MLS stations is assured by a network of optical fibers.

Abstract: The system comprises a central station assuring the generation of the microwave signals which must be transmitted by the different stations of an MLS. The signals thus generated in a centralized way are distributed to the different stations via an optical fiber network, the stations then assuring only the amplification and transmission of the signals.

Abstract: A method of receiving pulses of the M.L.S. type and a system for implementing this method. The method comprises a dividing stage for dividing the received pulse into zones (Z1, . . . Z8). A mean value is determined of the samples within each zone in order to obtain the points PI(1) . . . PI(8). The straight line DR at best passing through these points provides the instant (tMAX) which is the "time" of the pulse.

Abstract: A portable siting system particularly useful for siting a portable localizer for a collocated approach guidance system for aircraft utilizes a laser range finder in conjunction with a shaft encoder to determine the distance between the localizer and two arbitrary points along a runway center line as well as the azimuth offset between the two points. A microprocessor is used to compute the number of degrees the antenna of the localizer must be rotated so that its beam intersects the extended runway center line at a predetermined point based on trigonometric computations performed on the two measured distances and the measured angle.

Abstract: A guidance system for landing an aircraft is described which uses a source of signals identifiable with the aircraft and a ground station which is linked to the aircraft. Specifically, the ground station includes a receiver which is connected to one or more pairs of antennas having a fixed, overlapping, directional sensitive pattern symmetically located relative to the center of the landing path, a receiver and a processor for measuring the relative sensitivity of the signals received at the antennas and for using the relative signal intensity to determine the location of the aircraft relative to the center of the landing path.

Abstract: Field monitor antenna is located to receive reciprocally scanned guidance beams. A pair of test pulses having a time interval which is determined by the field monitor antenna location are generated from a test pulse generator during a dead time period of the guidance beam scanning. TO-pulse and FRO-pulse pulses in response to the guidance beams and those of the pair test pulses are supplied to a monitor. The monitor measures a first and a second time interval between the TO-pulse and the FRO-pulse of the signals from the test pulse generator and from the field monitor antenna. Monitor verification means verifies the normalcy of the monitor on the basis of the measured first time interval and verifies the normalcy of the guidance beam on the basis of the measured second time interval.

Abstract: There is disclosed a microwave landing system wherein there are provided at least two means which are spaced by a predetermined distance and from two of which beams radiate alternately to scan a predetermined region vertically and horizontally. In the microwave landing system, multipath propagating beams due to the scanning beams or side-lobes thereof are of out of phase or in non-correlation with each other in a receiving means in an aircraft to suppress multipath errors.

Abstract: A microwave landing system in which a beam scanning antenna is provided with an amplifying function to constitute an active array, a traditional power amplifier and the like are omitted to enhance the reliability of operation. The outputs of phase shifters each being associated with a respective one of radiating elements are connected to 1/2 dividers each having p-i-n diodes at opposite output terminals thereof, and the p-i-n diodes of each 1/2 divider are turned on and off alternately. Output signals are fed to radiating elements and a multiplexer with a minimum of loss.

Abstract: The fault monitoring function of an executive monitor contained in a microwave landing system is verified by evaluating a history of the parametric information sampled by an executive monitor and storing in memory the number of out of tolerance parametric signals received from an antenna means over a predetermined time period, replacing the stored number of out-of-tolerance parametric signals with a predetermined number that will be beyond a second predetermined limit if another out-of-tolerance parametric signal is added to said number, adding one such internally generated out-of-tolerance parametric signal to said predetermined number, generating an alarm if said sum is beyond the second predetermined limit, and restoring the previously stored number of out-of-tolerance parametric signals received from the antenna means if the alarm was generated, and shutting the system down if an alarm was not generated.

Abstract: An airport landing system includes an airborne transmitter and receiver for transmitting RF energy at a first frequency and receiving RF energy at a second frequency. A stationary RF energy focusing means for focusing received RF energy. At least four receive/transmit modules and at least one RF source module. The RF source module for amplitude modulating and amplifying the received RF energy for retransmission by the receive/transmit modules. The receive/transmit modules having RF energy collector horns physically arranged with at least two vertically disposed horns and two horizontally disposed horns for transmitting at least four relatively high gain powered beams whose patterns cross over at their half power points with the crossover point defining the approach path.

Abstract: In a microwave holographic device, the main lobe of a microwave antenna is spatially scanned to receive a microwave signal reflected from an object. The received microwave signal is mixed with a reference signal to generate two-dimensional electric information, synchronized with the scanning. The two-dimensional electric information is used to change the optical properties of an electrooptic material, and then the optical property changes are read out to obtain a holographic image.

Abstract: In the basic configuration of the microwave landing system, an azimuth station (2) and an elevation station (1) are interconnected by a data link for transferring data and sync signals, and each of the stations includes a monitoring facility (10, 15; 3, 8) for monitoring its signals in the near field. In the novel microwave landing system, the near-field monitoring facility of one of the stations is also used to monitor the signals from the other station in the far-field.

Abstract: A method and device for monitoring a station in a landing aid system of the MLS type comprising two transmission assemblies. Transmission from the electronic sweep antenna is provided alternately by said two transmission assemblies, the operation thereof being permanently tested and switching thereof being performed as a consequence.

Abstract: A method for the radioelectric synchronization of slave stations by a master station, especially for a MLS type landing control system. The method consists in transmitting by the azimuth station a synchronization data coded in the form of a series of short duration pulses, prior to each MLS cycle, a cycle being constituted by a plurality of successive transmission of MLS functions.

Abstract: The invention provides independent guidance and monitoring integrated into an MLS landing system and a scaled-down MLS take-off or missed approach guidance system useable at small airports. An added fixed beam precision guidance system is integrated into the MLS time sequence format. The fixed beam guidance system is based upon the concept of using paired fixed overlapping beams, sequentially radiated by different fixed antennas (80 and 81), oriented to left and right of a prescribed guidance path. The paired beams overlap at the prescribed guidance path in such a manner that an aircraft departing or making a missed approach on such path will intercept equal signal intensities to indicate an on-course condition.

Abstract: A microwave landing system incorporates a set of antennas for the sequential transmission of guidance signals through a sequence of directions to enable the reception and decoding of the signals by an airborne receiver. Circuitry is included for the retransmission of a frame of the signals by a procedure wherein the directions of transmissions is altered so as to increase the guidance sector over which the receiver is effective.

Abstract: A scanning system for a phased array antenna for operation at a selected frequency between a first frequency and a second frequency includes the storage of phase shift command signals for each of the phase shifters coupled to radiating elements of the antenna. The memory which stores the phase shift commands is addressed sequentially to provide for a step-wise scanning of a beam of radiant energy at a first frequency of the antenna. The addressing is accomplished by incrementing a count resulting from a counting of clock pulses. Compensation for the stepped positions of the beam for the difference between the selected frequency and the first frequency is accomplished by altering the number of pulses which increment the count of the addressing. The altering is accomplished by the storing of sequences of clock pulses at varying temporal spacings which are used for gating out selected ones of the incrementing pulses.

Abstract: The invention provides independent guidance and monitoring to be integrated into an MLS landing system and also provides a scaled-down MLS landing guidance system useable at small airports. In both cases an added fixed beam precision guidance system is integrated into the MLS time sequence format. The fixed beam guidance system is based upon the concept of using paired fixed overlapping beams, sequentially radiated by different fixed antennas. One pair is oriented to left and right of the centerline of the runway, and the other pair is oriented above and below the desired glideslope. The first set of paired beams overlap at the centerline of the runway in such a manner that an aircraft approaching exactly on centerline will intercept equal signal intensities to indicate an on-course approach.