Abstract: An AC power source applies power to a primary coil that is provided in a fixed part. An AC current flowing through the primary coil induces electromotive force in a secondary coil that is provided in a movable part. The AC electromotive force induced in the secondary coil is converted by an AC/DC converter into DC power, which is input to a drive control section.

Abstract: A method for determining the velocity of features such as wind. The method preferably includes producing sensor signals and projecting the sensor signals sequentially along lines lying on the surface of a cone. The sensor signals may be in the form of lidar, radar or sonar for example. As the sensor signals are transmitted, the signals contact objects and are backscattered. The backscattered sensor signals are received to determine the location of objects as they pass through the transmission path. The speed and direction the object is moving may be calculated using the backscattered data. The data may be plotted in a two dimensional array with a scan angle on one axis and a scan time on the other axis. The prominent curves that appear in the plot may be analyzed to determine the speed and direction the object is traveling.

Abstract: A method and a radar sensor for determining an elevation angle error of a multibeam radar sensor are described. In order to detect an elevation angle of the multibeam radar system with respect to a predefined target, a plurality of laterally arranged cutting planes at a predefined distance are formed. The values of the corresponding antenna diagrams in each plane are stored in a suitable form, for example, normalized and in a parametric form taking into account the elevation angle &agr;. In order to reduce the size of the memory, it is sufficient to store one symmetry half for reasons of symmetry if additional information, for example, road clutter values are added, so that the upward or downward direction of the angle can be recognized. By comparing the measured echo values obtained by normalization and application of a quality factor, a corresponding elevation angle &agr; is obtained for each cutting plane.

Abstract: A radar apparatus comprises a signal transmitter device that transmits a signal, a scanner that two-dimensionally scans a target object using the signal transmitted from the signal transmitter device by engaging in longitudinal oscillation and lateral oscillation, a signal receiver device that receives a reflection signal of a signal transmitted via the scanner and a control device that controls a longitudinal oscillation signal and a lateral oscillation signal used to oscillate the scanner longitudinally and laterally in correspondence to the length of time over which a scanning observation is performed through a two-dimensional scan.

Abstract: The bistatic radar system uses a scanning beam antenna located at the transmitter to transmit a focused beam of high frequency energy into a predefined space, with the transmitted beam comprising a series of pulses. The transmitter also includes apparatus for determining pulse origination data comprising: pulse origination time and direction of propagation for each of the pulses in the transmitted beam emanating from the antenna, where the antenna is scanned in a predetermined scan pattern in at least an azimuthal direction. The bistatic radar system also includes at least one receiver, located at a site remote from the transmitter and includes apparatus for generating pulse component receipt data indicative of receipt of components of the pulses that are contained in the transmitted beam that are reflected from scatterers in the predefined space.

Abstract: The bistatic radar network uses an incoherent transmitter for determining the presence, locus, motion, and characteristics of scatterers in a predefined space. The incoherent transmitter generates pulses of high frequency energy that vary in frequency and/or phase. The bistatic radar network having an incoherent transmitter uses a scanning beam antenna located at the transmitter to transmit a focused beam of high frequency energy into a predefined space, with the transmitted beam comprising a series of pulses, each pulse in the series of pulses having a varying frequency, phase, pulse origination time and direction of propagation as it is emanated from said antenna. The transmitter also includes apparatus for determining pulse origination data comprising: frequency, phase, pulse origination time and direction of propagation, for each of the pulses in the transmitted beam emanating from the antenna, where the antenna is scanned in a predetermined scan pattern in at least an azimuthal direction.

Abstract: An antenna section radiates a pulse beam and receives its reflected wave, and a signal processing section observes a rain or cloud occurring region within a covered area based on a signal intensity of the reflected wave. In this case, to obtain wind direction and velocity information for the rain or cloud occurring region, the signal processing section observes Rayleigh scattering-induced Doppler echo components in that region to calculate the wind direction and velocity from a result of the observation. To obtain the wind direction and velocity information for a region other than the rain or cloud occurring area, the beam formed by the antenna section is directed toward the region to be observed so that the signal processing section can observe Bragg scattering-induced echo components based on a received signal of the reflected wave to calculate the wind direction and velocity from a result of the observation.

Abstract: An AC power source applies power to a primary coil that is provided in a fixed part. An AC current flowing through the primary coil induces electromotive force in a secondary coil that is provided in a movable part. The AC electromotive force induced in the secondary coil is converted by an AC/DC converter into DC power, which is input to a drive control section.

Abstract: A system and method for detecting, processing, and displaying weather radar information which uses multiple scans, at differing antenna tilt angles, to generate a single displayed image. This can be used to reduce displaying of ground clutter returns and to simultaneously increase the range of weather information displayed on a single image.

Abstract: A system and method for detecting, processing, and displaying ground mapping radar information which uses multiple scans, at differing automated antenna tilt angles, to generate a single displayed image. This can be used to increase the scanned area of a ground display so as to allow a complete sampling of the ground ahead of the aircraft.

Abstract: A system and method for enhancing turbulence detection, display and alerting with avionics weather radars which includes automatically making multiple scans, measuring a wind velocity gradient at varying elevations, and comparing the measured gradient to known predetermined wind velocity gradients over known elevation variations, wherein the predetermined gradients have known vertical shear components, and using a vertical shear component information in making determinations regarding the existence of turbulence.

Abstract: The multiple beam radar system uses multiple simultaneously transmitted beams of high frequency energy to identify scatterers that are located in a predetermined volume of space. This multiple beam radar system simultaneously transmits several beams of high frequency energy, produced by an antenna which operates in a mechanically scanning mode, and simultaneously receives the returned radiation, which constitutes components of this narrow beam that have been reflected off scatterers located in the path of the beam. The transmitted (and thus received) frequency of each beam is different, providing information relating to the presence, locus and characteristics of the scatterers by analyzing the plurality of received beams.

Abstract: A vehicular radar includes a transmitter for outputting a transmitted electromagnetic wave; an antenna unit for radiating the transmitted electromagnetic wave and receiving a electromagnetic wave reflected by an object to be detected as a received electromagnetic wave; a receiver for detecting the reflected electromagnetic wave received by the antenna unit; and a signal processor for processing an output signal from the receiver to output information about the object. The antenna unit includes a single electromagnetic radiator for radiating the transmitted electromagnetic wave, a single reflector for reflecting the transmitted electromagnetic wave from the electromagnetic radiator and radiating the transmitted electromagnetic wave as a beam, and a reflector swinging device for swinging the reflector so as to successively change a direction of the beam. The reflector swinging device includes a first arm, a second arm, a swinging pivot, a cam and a cam follower.

Abstract: A method is provided of optimizing, within an area which itself contains a number of part areas, the coverage of a sensor which has an angle-dependent range in a least one plane, and which sensor is in addition arranged on a mobile platform. The method includes determining at least two movement directions for the sensor platform, determining a center of movement for the two movement directions, and also determining periods of time during which the sensor platform is to move in each of the two movement directions. The center of movement of the platform is preferably located within the search area.

Abstract: There is provided a rocket trajectory estimating method comprising the steps of: measuring a GLOS angle of a flying rocket a tracking system; passing the GLOS angle data through a batch filter to reduce noises; estimating a rocket trajectory on the basis of the GLOS angle data, the noises of which have been reduced; passing the resulting rocket trajectory data through a Kalman filter to reduce biases; and estimating the rocket trajectory again on the basis of the corrected GLOS angle data and the positional information of the tracking system. Thus, there is provide a rocket trajectory estimating method capable of reducing observation errors (noises and biases) of a tracking system of a passive ranging system, which does not have need of any laser range finders, to enhance the accuracy of rocket trajectory estimation.

Abstract: A radar apparatus comprising: a receiving antenna having an array antenna in which a plurality of antenna elements are arrayed in a horizontal direction; and a signal processing section for carrying out recognition of a target existing in a predetermined horizontal bearing range from receive signals received by the receiving antenna, by electrically carrying out horizontal scanning of an antenna pattern of the receiving antenna, wherein at least one of the antenna elements is placed with a shift in a vertical direction, and wherein the signal processing section detects an altitudinal bearing of the target by a monopulse method by use of a receive signal from the antenna element with the shift in the vertical direction.

Abstract: A method and apparatus for automatically controlling the tilt of a radar antenna to avoid ground clutter returns while scanning the weather formations of most interest. In one embodiment a terrain database is utilized to determine tilt angles for different terrain cells. The tilt angle is determined starting at the aircraft position and working out to the radar range. If a tilt angle for a more distant cell is less than for a nearer cell it is ignored taking shadowing into account. In another embodiment the weighted tilt angle frequencies are entered into a histogram and the histogram is scanned to obtain a tilt angle resulting in an acceptable amount of ground clutter.

Abstract: A method and apparatus for testing an antenna control system. The antenna control system having an antenna control unit electrically coupled to an antenna pedestal. The present invention simulates the operational environment of the antenna control system and records the systems responses to the simulation. The responses are then analyzed and the antenna control system is adjusted to correct errors.

Abstract: A monopulse system generates sum (.SIGMA.), elevation difference (.DELTA..sub.EL), azimuth difference (.DELTA..sub.AZ), and double difference (.DELTA..sub..DELTA.) signals, and generates a covariance matrix. The covariance matrix is decomposed to produce at least the principal eigenvector. The location or angular direction within the main beam of a single target is determined from the real component of the quotient of elements of the principal eigenvector, by the use of a look-up table. In another embodiment of the invention, the eigenvalues are generated from the covariance matrix, and the number of significant eigenvalues determines the number of targets within the main beam. If a single target is found, its location is found as described above. If two targets are found in the main beam, the locations of the two targets are determined by a closed-form solution of quadratic equations.

Abstract: The invention relates to a radio system where oriented antenna beams are used over a radio connection between a network subsystem and a subscriber terminal with a fixed location. The network subsystem comprises means for storing parameters of a bidirectional radio connection, including e.g. the transmit beam angle, the receive beam angle, the air interface delay profile, the air interface impulse response, the transmit power of the network subsystem, the transmit power of the subscriber terminal, and the number of rake branches. The network subsystem also comprises a common measuring unit that measures parameters of a bidirectional test radio connection of a new user.

Abstract: In a method of adjusting the axis of a car on-board radar, especially, a car on-board mono-pulse radar having the function of transmitting radio waves, light or ultrasonic waves, a car axis and an offset axis are set and the mount angle of an antenna offset-mounted on the offset axis can be adjusted with high precision and with ease through a reduced number of process steps.

Abstract: A computer vision system is disclosed that utilizes a spinning array of podetectors. The array is rotated about the focal plane of a lens and scans all the possible orientations and positions of the edges of the unknown object. In one embodiment, the photodetectors are elongated so as to provide for maximum light gathering ability along the direction of elongation and a minimum light gathering ability in the direction perpendicular to the direction of elongation. In other embodiments, optical means are used to focus the image onto conventional photodetectors while still having the ability to more efficiently determine edge segments of unknown objects. The system efficiently and rapidly implements the wavelet projection transform to characterize-multi-scale edge segment features of an image of an unknown object. An imaging radar system that utilizes a spinning antenna system having frequency scanning provisions is also disclosed.

Abstract: An extended spatial acquisition method extends the spatial acquisition range for tracking antennas. The method employs a multiple feed cluster to sense the received signal with high sensitivity and to spatially acquire the received signal when uncertainty in the received signal arrival direction exceeds several beamwidths. A main beam consisting of a collection of beams including a central beam and surrounding beams of the cluster extend the spatial acquisition range to include the surrounding beams. Feed signal strengths are measured to determine where within the extended field of view a desired signal arrives and then the antenna is repositioned to point the central beam toward the desired signals after which central beam tracking occurs.

Abstract: A method for guiding a missile to a target. The method includes the step of providing a surface-based radar system having an electronically beam steerable antenna system adapted for continuous mechanical rotation about an axis. During a pre-terminal, semi-active missile homing guidance phase, the beam produced by the antenna system is electronically rotated by the antenna system in a direction counter to the direction of the mechanical rotation of the antenna system to thereby increase radar system illumination time on the target. Further, during the increased illumination time, the beamwidth of the surface-based radar system beam is increased. During, a subsequent terminal, active homing missile guidance phase, guiding the missile to the target with the pre-terminal, semi-active missile homing guidance phase using the surface-based radar system and establishing an angular orientation for a missile-borne antenna system at the commencement of the terminal, active missile homing guidance system phase.

Abstract: A satellite tracking method for a vehicle-mounted receiving antenna system to determine the orientations of satellites dependent upon the moving direction of a moving body such as an automobile associated with the attitude control of an antenna which is mounted on the moving body for the purpose of receiving satellite broadcasting signal, the method including an initial mode, a maximum value search mode, a normal tracking mode, an error correction mode, a signal blocking mode and a rainfall mode.

Abstract: An autotracking antenna system operable to cause a steerable antenna assembly to automatically track a moving RF video signal source has a reflector, a rotator for positioning the reflector at any desired position in azimuth and elevation, a primary antenna element positioned to receive an RF video signal reflected from the center of the reflector, and a series of offset antenna elements each positioned to receive an RF video signal reflected from a different off-center location on the reflector. A tracking control processor is operable to select and receive video signals from the primary antenna element and the offset antenna elements and to control the rotator, and a signal receiver receives video signals from the antenna element and has a video signal output.

Abstract: An adaptive receiving antenna reduces interference arriving in the main beam of the antenna by redirecting the antenna beam away from the interference source. The receiving antenna projects the main beam to receive desired source signals from a source direction and may receive interfering signals from the interfering source. The antenna system measures the strength of the source signal and interference signal for controlling the direction of the main beam to marginally decrease the received desired source signal while substantially decreasing the received interfering signal to increase the desired source signal to interfering signal ratio so that the desired source signal can be received in the presence of interference.

Abstract: Radar system for the generation of two-dimensional or three-dimensional position indications of targets. Three-dimensional position indications are obtained by periodically canting the antenna about a canting axis, such that the antenna beam plane makes an angle with a normal on the earth's surface and by combining azimuth data and range data obtained at different canting angles. For a radar system provided with dual-axis stabilization means, these means may also provide for the canting of the antenna means.

Abstract: A method and apparatus for pointing a tracking antenna to a communication satellite in the initial stage of satellite tracking by means of frequency shifting, upon reception of a carrier wave having deviation from the accepted standards of frequency, the antenna initial pointing apparatus including a downconverter for converting a signal received at a directive antenna to an IF signal, a synthesizer for providing the downconverter with a local signal for the IF signal conversion, a power detector for detecting the power of the IF signal, and a controller for controlling the synthesizer to generate the local signal and also for controlling the rotation of the directtive antenna. Based on a detected result from the power detector, a downconverted IF signal having deviation from the accepted standards of frequency is further converted to be included within a limited bandwidth of the power detector by means of frequency shifting.

Abstract: A radar system is provided to track radar energy reflected by a point on the target different from the centroid of a target's radar reflected energy. The radar system includes a target angle/range tracking system and a target energy monitoring/range tracking system. During a first mode of operation, the target angle/range tracking system tracks the centroid of the target's reflected energy; and, the target energy monitoring/range tracking system monitors the strength of energy reflected from points, or regions along the body of the target different from the centroid reflected energy producing region. When the signal strength to noise ratio (i.e., S/N ratio) from a reflection at one of the monitored points along the target exceeds a predetermined level indicating detection of a secondary reflector along the body of the target, a second operation mode commences.

Abstract: An antenna tracking controller for generating signals used to position an antenna for tracking a moving signal source includes a first Kalman filter for estimating parameters of a first model of the motion of the moving signal source a second Kalman filter for estimating parameters of a second model of the motion of the moving signal source. The second Kalman filter uses the parameters estimated by the first Kalman filter as initial values. A model quality charge/discharge is also provided to monitor the status of the data base.

Abstract: A radar apparatus provided with a Cassegrain antenna to be mounted on the barrel of a gun. The Cassegrain antenna is of the polarization twist type with a flat adjustable mirror being used to generate a lead angle. In addition, gun-induced vibrations transmitted to the Cassegrain antenna are compensated by adjusting the flat mirror so that the radar beam generated by the Cassegrain antenna is not susceptible to these vibrations.

Abstract: A direction adjustment indicator for a satellite radio wave receiving antenna comprises a demodulating circuit to demodulate a satellite radio wave received by the antenna, a peak holding circuit always to output a held peak value of the demodulated output of the demodulating circuit, a comparator circuit and a display element. The comparator circuit compares the instantaneous value of the demodulated output and the held peak value, and outputs a signal when both values are equal and another different signal when both values are not equal. The display element gives two different kinds of display in accordance with the signals. While the azimuth angle of the antenna is varied in one direction, a peak value of the demodulated output is held and while the angle is varied in the opposite direction, the optimum azimuth angle is displayed for which the instantaneous value of the demodulated output agrees with the held peak value.

Abstract: A tracking system for enabling maintenance of alignment between a receiver of electro-magnetic radiation and a source of electro-magnetic radiation signals, the system comprising: a receiver; a sensor associated, in use, with the receiver to sense the strength of the signal received by the receiver; and an interrupter device, which in use, intermittently interrupts one or more discontinuous eccentric portions of the signal being received by the receiver thereby attenuating the received signal by an extent which is dependent upon the degree of misalignment of the receiver from the transmitter.

Abstract: A weather radar system is operable in an automatic mode for positioning the radar system antenna beam to scan an elevation axis between upper and lower scan limits in incremental steps as selected by a user while continuously scanning an azimuth axis for enhancing the analysis of weather conditions.

Abstract: A method and an apparatus for adjusting the direction of an antenna on the basis of the C/N in a satellite broadcasting receiving system are disclosed. When the image quality is insufficient with the antenna direction in a displaying mode, a user specifies a fine adjustment mode through a key input portion. Then the current antenna direction is stored into a memory as a fine adjustment start position. A CPU deflects the antenna within a predetermined measuring range around the fine adjustment start position. The CPU detects one or more peaks of the C/N level and discriminates non-objective peaks. If the C/N level exhibits a plurality of peaks resulting from the signal reception, the CPU selects the antenna direction corresponding to the peak closest to the fine adjustment start position.

Abstract: An antenna is divided into a plurality of sub-arrays which are arranged parallel to each other on a turntable. At least one of the sub-arrays is laterally divided into sub-array sections. Reception signals from these sub-array sections are compared with each other to detect a phase difference therebetween. This phase difference is utilized to control the beam direction of the antenna such that the antenna can be properly oriented to the satellite at all times.

Abstract: Attitude control is implemented by detecting the phase difference between signals received by at least two antennas and detecting the angle of deflection between the direction of arrival of radio signals and the antenna beams. By using antennas that are separately driven, within the plane of rotation in which the deflection angle is to be detected, the phase of the received signals can be shifted equivalently to when the antennas are driven as a consolidated unit. Also, when at least three antennas are used in an orthogonal arrangement for detecting the deflection angle in two directions, the antennas are divided into two groups which are individually driven. This reduces the inertia of the moving parts and enables the size and weight of the drive mechanisms to be reduced.

Abstract: Air-to-ground radar (2) is stabilized by comparing the power of the returning echo occurring during an initial period after the transmission of each pulse with that occurring during a following period after the transmission of each pulse, and using the result of this comparison to control an elevation controller (13) of the radar (2). Means (7, 8) provide a first power signal representative of the power of the returning echo occurring during an initial period after the transmission of each pulse, means (7, 9, 10) provide a second power signal representative of the power of the returning echo occurring during a following period after the transmission of each pulse, and a comparator (12) compares the magnitude of the first and second power signals and outputs a control signal causing the elevation controller (13) to raise or lower the elevation at which output pulses are projected.

Abstract: A method for orienting a radar installation which possesses an at least approximatingly axial-symmetrical antenna radiation or beam characteristic towards a target. The radar beam which is emitted by the radar installation is reflected or scattered back at the target and the backscattered radar beam is evaluated or plotted in a measurement evaluating device of the radar installation for purposes of determining or identifying the target. Employed is a target with three target elements which are arranged in the corners of an at least approximately equilateral triangle, the centerpoint of which corresponds to the desired target point, in which there is effected a separating of the three radar signals which are reflected or scattered back by the three target elements, and that from the values of the amplitudes of the three backscattered radar signals, through the utilization of the measurement evaluating circuit, there is determined the position of the target point which is located between the target elements.

Abstract: Apparatus and methods for tracking a positioning system for antennas and other devices. Hardware of the invention contains circuitry which when given velocity information, changes its output position information at a specified rate. The hardware may also be triggered to capture a sample of such output position information to provide feedback to the firmware of the invention, which implements a position tracking algorithm. The algorithm utilizes two consecutive input position samples, the time between those samples and the feedback information corresponding to the last position input sample to calculate the velocity to be applied to the position tracking hardware until a new position input sample is available. When the new sample is available, a new velocity is calculated and applied to the hardware and the process is repeated. Between position input samples, the hardware updates the output position to correspond to the motion of the positioning system.

Abstract: In a tracking radar system target glint and multipath sometimes produce signals which falsely indicate high acceleration rates of the target. These signals cause the boresight of the antenna to be driven away from the direction in which the target actually lies.To avoid this problem, received signals from a receiver are fed through a switch which is opened whenever the target appears to have an acceleration or velocity above a threshold value. The threshold value is varied so that the proportion of the time during which the switch is open is kept approximately constant. Thus, if there is a period during which a large number of high acceleration or high velocity signals appear from the receiver (for example is there is a very high noise level) the switch still remains closed for a certain proportion of the time period. This ensures that the tracking system never loses the target while also ensuring that false tracking due to target glint and multipath is minimized.

Abstract: An antenna tracking system tracks a primary antenna to follow a moving signal source, such as a communication satellite. A secondary antenna has a greater beam width than the primary antenna and receives the same tracking signal from the satellite. The primary antenna is tracked according to a predetermined search pattern which causes a variation in the signal amplitude depending upon the relative location of the satellite and the antenna position. The signal strength signals from the two antennas are input to a summation function which takes the difference of the two signals. The noise and signal variation component of the two signals is substantially the same and is therefore eliminated from the resulting difference signal. An antenna control unit utilizes the resulting difference signal to select the optimum signal strength for the particular step of the search pattern.

Abstract: An error-free pointing and tracking system is disclosed which separates the functions of pointing and tracking. Beginning with an initialized trajectory for an object, a sensor is positioned and deviations of the object position with respect to the sensor are noted. To the extent these deviations are trended, the gain of a trajectory correction algorithm is adjusted. Based on the adaptive gain trajectory correction algorithm, a new position estimate is determined. The new position estimate is corrected for servo lag error by referring to a predefined correlation between at least the acceleration term of the trajectory and prerecorded servo lag error. The position estimate, corrected for servo lag is used to then point the sensor.

Abstract: A shipboard search radar in which an antenna beam is stepped up and down in elevation to keep the beam pointed approximately toward the horizon even though the ship may be rolling and/or pitching.

Abstract: The target tracking system has high tracking reliability at small servo load and comprises a plural number of groups of target sensors having tracking signal travelling times which vary from one group to the other and defining respective lines of sight, a servo system causing the lines of sight to track the target, a target estimator for estimating the movement of the target, a servo estimator for estimating the movement of the servo system, and a regulator which identically controls the servo system and the servo estimator such that the vectorial difference between the estimate of the target movement and the estimate of the servo movement is caused to approach zero. During the target tracking operation, vectorial target deviation signals which are generated by groups of angle sensors, are processed by multipliers using respective matrices in order to produce related combined target deviation signals.

Abstract: The invention relates to a means for calibrating the elevation and azimuth angles of the scan axis of an antenna. Said means comprises a mobile target remote from the antenna, a video approach camera for detecting the mobile target, a theodolite equipped with a telescope having a reticule with two crossed designating axes, a video camera for the acquisition of the reticule image and images supplied by the telescope, means for controlling the guidance of the displacement of the target, so that the latter is positioned at a predetermined distance from the antenna in the vicinity of the scan axis, so that the image of the target in the telescope is as close as possible to the reticule axes.

Abstract: A high frequency target seeking device, using a stabilized reflector antenna, performs range search and tracking functions and target angle search and tracking functions. A technique is provided for target range discrimination using several narrow band i.f. filters, also thereby improving signal-to-clutter ratio and signal-to-receiver noise ratio. Target search is accomplished with simultaneous range and antenna azimuth scanning, with the range bins and the antenna beam swept across the target. A multiplexer selects the range bin having signals indicative of the target. Target range tracking is accomplished by the multiplexer additionally automatically selecting range bins adjacent to the target's range bin and comparing their output signals. Antenna stabilization is accomplished utilizing signals from vehicle pitch, roll, and yaw rate sensors, and antenna elevation and azimuth rate and angle sensors.