Abstract: A method is disclosed for evaluating the terrain surrounding a radar site. The method comprises to calculate the radar horizon around a radar site from stored terrain elevation information. The information obtained can be used for controlling the scanning profile of the radar, by letting the radar scan above the calculated horizon, and thus avoiding transmitting into the terrain.

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

Abstract: An electromagnetic wave is transmitted from a signal transmission antenna using a signal transmission IC; this electromagnetic wave is received, after having been reflected by a target object, by signal receiving antennas and signal receiving ICs; and the distance to the target object or the azimuth of the target object is detected by a signal processing section. The signal receiving antennas have approximately the same signal receiving characteristics and directivity in approximately the same direction, and are arranged in a row with a predetermined gap between them, thus constituting an antenna array.

Abstract: Methods and apparatus are provided for operating a radar system to provide a thunderstorm image to a pilot. The method comprises using one or more radar scans depending upon the aircraft altitude, a single upward tilted scan at or below a datum level of about 15,000±3000 feet wherein a clutter free storm image may be obtained and two scans above the datum level; a first upward tilting scan to determine, clutter free, a storm head perimeter and a second lower tilting scan for the storm body with ground clutter. The perimeter is used to discard return echoes from the second scan that lie outside the perimeter or an expansion thereof and retain those lying on or within the perimeter. The result is presented to the pilot. Optionally, the thunderstorm image is graded from center to edge so as to indicate weaker echo intensity near the edge.

Abstract: A method and an antenna arrangement are disclosed for reducing the antenna radar cross section for an externally illuminating radar source. A radar pulse is transmitted with the antenna arrangement fully matched to achieve a lowest possible power loss of the pulse. At all other times the antenna will be poorly matched and thereby will act as a low radar cross section. The reduced radar cross section leads to an antenna gain reduction, which most often can be accepted since competing noise is reduced as much as the useful signal. It is further suggested that the range gate of the receiver and the transmitter pulse control the antenna. Thus, the antenna is “fully opened” during the transmitting pulse and may be partly or “trade-off” matched during range gate reception. In the interval of not transmitting or receiving, the antenna will present a low radar cross section.

Abstract: An imaging apparatus has transmitter illuminating a selected surface with a radar beam footprint, and processor for profiling/processing the radar returns so as to derive attitude information in real time about a number of predefined axes associated with the radar which depends upon the relative dispositions of the radar, the selected surface and upon the radar beam footprint characteristics. A plurality of transmit beams image the surface and the processing arrangement has the capability of determining roll, pitch and/or yaw pointing data associated with the radar, such pointing data being determined by derivation of the attitude information and by selective input of terrain elevation data so as to take account of variations in the radar viewing geometry with terrain elevation. This provides a low cost advantage over known radar designs, and retains utility for many applications, for example spaceborne and airborne applications.

Abstract: A target tracking arrangement predicts the state of a target. The predictor may be a Kalman filter. In the presence of a target which is maneuvering, the prediction may be in error. A maneuver detector is coupled to receive residuals representing the difference between the predictions and the target state. The maneuver detector is matched to the predictor or Kalman filter to thereby tend to reduce the undesirable effects of system noise. The matching may be of the frequency response.

Abstract: An inspection system uses microwave radiation to capture a microwave image of a transportable item. The system includes a transmit scanning panel including a transmit array of transmit antenna elements, each being programmable with a respective phase delay to direct a transmit beam of microwave radiation toward a target of the transportable item for transmission of the microwave radiation through the target. The system further includes a receive scanning panel including a receive array of receive antenna elements, each being programmable with a respective phase delay to receive a receive beam of microwave radiation from the target. A processor measures the amplitude and phase of the microwave radiation in the receive beam to determine a relative value of a pixel within the microwave image of the transportable item based on a reference value of the pixel.

Abstract: An automotive radar which can process signals at high speed to detect a target in a wide angle range is provided. The automotive radar comprises a transmitting antenna which emits an electromagnetic wave, two receiving antennas which receive the electromagnetic wave reflected by a target, an antenna plate on which the transmitting antenna and two receiving antennas are arranged. It also includes a drive which rotates the antenna plate in an azimuth direction, which corresponds to the direction of arrangement of the two receiving antennas, to scan a detection angle formed by the two receiving antennas. The drive has rest time between scans to stop rotation. The automotive radar also includes a signal processor which detects the azimuth angle of the target with respect to a reference direction during the rest time according to received signals from the two receiving antennas and the rotation angle of the antenna plate at rest.

Abstract: A method of adapting weather radar thresholds is disclosed. The method comprises generating a location from a location sensor, retrieving information representative of a weather type from a database, based on the location, and adjusting, automatically, the threshold for a radar display based on the information.

Abstract: Provided is a bistatic and multistatic system for detecting and identifying a target in close proximity to an orbiting satellite. An electromagnetic fence is established to surround the satellite, using a ground-based communication uplink from a gateway antenna. A contact or breach of the electromagnetic fence by the target is detected by the satellite, or at other sensor locations, and an exact position, range and ISAR image of the target is calculated using scattered RF energy from the fence. Identification data is transmitted to satellite system monitors, whereby the data is used to decide on a corrective course of action.

Abstract: An attitude sensing apparatus for determining the attitude of a mobile unit is provided that can reliably estimate an alignment angle between a GPS antenna coordinate system and an IMU coordinate system with good accuracy regardless of the magnitude of the alignment angle. Based on observation of the difference between a GPS angular velocity and an IMU angular velocity, an alignment angle estimating section estimates an alignment angle and sensor errors. An alignment angle adder and a sensor error adder cumulatively add and update the estimated alignment angle and sensor errors, respectively. The estimated alignment angle is fed back to an inertia data converter while the estimated sensor errors are fed back to an inertia data correcting section. The apparatus repeatedly performs estimation until the estimated alignment angle gradually approaches a true alignment angle by successively feeding back estimated values to a flow of alignment angle estimation process.

Abstract: The invention relates to a device for improving the visibility conditions in a motor vehicle, having a radiation source for infrared radiation for irradiating the surroundings of the vehicle, having an infrared-sensitive camera for taking images of at least part of the irradiated surroundings, having a display unit for displaying collected image data, and having a control unit for controlling the device. Furthermore, a sensing unit for a recommended maximum velocity vmax is provided and is connected to the control unit. A velocity sensor which is connected to the control unit is provided in such a way that the control unit causes the display to be switched off when the vehicle velocity v exceeds the maximum velocity vmax. The display is preferably switched on when the vehicle velocity v drops below the maximum velocity vmax.

Abstract: An active protection system comprising an ultrawideband radar for threat detection, an optical tracker for precision threat position measurement, and a high powered laser for threat kill or mitigation. The uwb radar may use a sparse array antenna and may also utilize Doppler radar information. The high powered laser may be of the optically pumped solid state type and in one embodiment may share optics with the optical tracker. In one embodiment, the UWB radar is used to focus the high power laser. Alternative interceptor type kill mechanisms are disclosed. In a further embodiment, the kill mechanism may be directed to the source of the threat.

Abstract: A first Kalman filter estimates true measures of yaw rate and vehicle speed from associated noisy measures thereof generated by respective sensors in a host vehicle, and a second Kalman filter estimates therefrom parameters of a clothoid model of road curvature. Measures of range, range rate, and azimuth angle from a target state estimation subsystem, e.g. a radar system, are processed by an extended Kalman filter to provide an unconstrained estimate of the state of a target vehicle. Associated road constrained target state estimates are generated for one or more roadway lanes, and are compared—either individually or in combination—with the unconstrained estimate. If a constrained target state estimate corresponds to the unconstrained estimate, then the state of the target vehicle is generated by fusing the unconstrained and constrained estimates; and otherwise is given by the unconstrained estimate alone.

Abstract: The invention is a system and method for verifying the radar signature of a pair of aircraft. The system includes a radar transmitter and receivers located in the leading and trailing edge of the wing at the wing tip of the aircraft such that when flying the aircraft in formation with one aircraft behind the other aircraft, each aircraft can illuminate the other and verify the radar signature of the other.

Abstract: Calibrating an antenna includes receiving a signal sent from a reference located within a region. The signal has a polarization within an expected polarization range. Polarization value sets are established in accordance with the expected polarization range. Polarization ratios are generated from the plurality of polarization value sets. A minimum polarization ratio variance for the plurality of polarization ratios is established. A polarization value set corresponding to the minimum polarization ratio variance is identified. A calibration correction is determined in accordance with the identified polarization value set.

Abstract: An apparatus for and method of employing synthetic aperture radar (SAR) images to automatically classify a target comprising emitting and collecting SAR signals at a plurality of squint angles, forming a plurality of SAR images of the target from the collected signals, the plurality of SAR images substantially having tilt angle diversity, automatically classifying the target from each of the plurality of SAR images, and generating a most probable target classification from the classifications of the plurality of SAR images.

Abstract: Estimating an antenna pointing error includes receiving a signal sent from a reference located within a region. A polarization ratio is evaluated over the region. A minimum polarization ratio variance for the polarization ratio is established. A location corresponding to the minimum polarization ratio variance is identified. An antenna pointing error is estimated from the identified location.

Abstract: A method for main beam alignment verification includes providing data pertaining to one or more patterns associated with an antenna, measuring power levels of a signal acquired by the antenna, and comparing the measured power levels with the data to determine whether a direction of the signal is incident upon a main beam of the antenna.

Abstract: An improved base station which cancels the effects of known fixed interference sources produces a signal substantially free from the interference sources thereby increasing total channel capacity. The adaptive interference canceler system includes a main antenna for receiving signals from other communication stations and at least one directional antenna directed toward an interference source. The main and directional antennas are coupled together such that an output signal substantially free from the interference is generated.

Abstract: A radar system derives a correction for an actual boresight (311) of a radar monopulse antenna mounted on a moving platform from ? data and ? data generated with respect to an a priori known, calibrated boresight (309). The monopulse antenna (602) is coupled to a ground position measuring system (616) while acquiring data. The radar receiver acquires a ? and ? synthetic aperture map of the same radar scattering location with respect to the calibrated boresight. ? SAR data and the ? SAR data are motion compensated using the position and velocity supplied by the ground positioning system. A computer forms a ratio of the aligned ? pixels to the aligned ? pixels for each of a plurality of aligned ? pixels located near the calibrated boresight. The correction for the location of the actual boresight of the monopulse antenna is computed by an analysis of the ratio of aligned ? pixels and corresponding aligned ? pixels over the radar scattering location.

Abstract: A radar system mounted in a reference vehicle can detect a distance and orientation of a preceding vehicle to thereby compute a relative position of a width center of the preceding vehicle. A curving radius of the reference vehicle is then detected for computing a relative rotation angle between a direction from the reference vehicle and a longitudinal direction of the preceding vehicle. Relationship between a relative rotation angle and a lateral bias of the relative position of the width center is previously prepared in a map. The computed relative rotation angle is applied on the map, so that the corresponding lateral bias is obtained to correct the computed relative position of the width center of the preceding vehicle. Thus, the width center of the preceding vehicle moving in an adjacent lane can be accurately estimated.

Abstract: A method for acquiring azimuth information is provided in which first and second planar patch antennas (11a, 11b) are disposed so that their sky coverage areas partially overlap to form a common area (2), thereby dividing the antenna sky coverage area into a first area (1), third area (3) and common second area 2, and an azimuth is limited utilizing azimuths acquired in the respective areas and the angle between the two antennas. As a result, azimuth limitation information can be effectively acquired even at a location where the sky is severely blocked and satellite information can be adequately acquired only at a small range of sky visibility.

Abstract: A method routes a plurality of entities (200) through a predetermined area. The method includes the steps of: providing a plan; providing a deterministic method for computing the plan for the plurality of entities (200), the plan including a plurality of routes and sets of scan points for each of the entities (200); and performing the method by each of the plurality of entities (200) independently from the other of the plurality of entities (200).

Abstract: A pulse radar system capable of mapping multiple targets essentially simultaneously using a single radar antenna. By alternately transmitting radar pulses toward multiple targets positioned at different angles relative to the antenna and alternately receiving return signals from the multiple targets as the radar antenna is switched between multiple beam positions, a time-interleaved radar operation is achieved which enables multiples targets to be mapped, and thus tracked, at the same time. A different radio frequency is preferably employed for each target so as to avoid interference and ambiguous returns. Using the teachings of the present invention, between two and twenty radar maps, and possibly more, can be generated simultaneously in approximately the same amount of time required to map a single target using conventional systems of the prior art.

Abstract: An airborne radar antenna system for detecting a target in a volume includes a tethered aerostat and an antenna that is supported above ground by the aerostat. The aerostat-based antenna is used for transmitting and receiving a radar beam into the volume to detect the target. Additionally, the system includes a ground-based transmitter that generates a beacon signal which monitors the antenna configuration at the aerostat. A computer then evaluates the beacon signal to create an error signal which is used to maintain a predetermined configuration for the antenna. The system also includes mechanisms for orienting the radar beam along preselected beam paths between the antenna and the volume.

Abstract: A method for estimating the curvature in a road is disclosed. The method measures an azimuth angle range and relative velocity between a host and a target vehicle, which determines whether a host vehicle is changing lanes or whether a target vehicle is changing lanes. The method calculates a heading angle of the host vehicle and calculates a corrected azimuth angle by adjusting the measured azimuth angle by the value of calculated heading angle. This method selects a curve that minimizes the mean square error between the curve and selected targets; and determines an equation that describes the curve, wherein the equation is used to predict the path head of the host vehicle.

Abstract: A method and system for pointing and stabilizing a device that needs to be pointed and stabilized with a desired direction, are disclosed, wherein current attitude measurement and attitude rate measurement of the device measured by an attitude producer, which includes an inertial measurement unit, and the desired direction information measured by a target coordinates producer are processed by a pointing controller to compute rotation commands to an actuator. An actuator rotates and stabilizes the device at the desired direction according to the rotation commands in the presence of disturbances and parametric uncertainties to account for the undesired vibration due to disturbances. A visual and voice device provide an operator with visualization and voice indication of the pointing and stabilization procedure of the device.

Abstract: The invention describes a device and a method for increasing the angular resolution in a radar system looking in the direction of motion and laterally thereto, wherein the doppler frequency shift of the transmitted signal is evaluated in order to increase the angular resolution. For this purpose, a plurality of adjacent, narrow regions are sampled sequentially by means of pencil-beam antenna characteristics during movement of the antennas. Relative to the total area, this is equivalent to illumination with a broad-beam antenna characteristic. The results from the simulation of this broad-beam illumination are combined with the results of the pencil-beam sampling processes in order to achieve an increase of the angular resolution of the antenna array.

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: The method of controlling travel speed of a vehicle includes controlling vehicle travel speed according to a set vehicle speed given by a driver of the controlled vehicle in a speed control mode; detecting at least one object present in front of the controlled vehicle and measuring distance to and relative speed of the at least one object when present in front of the controlled vehicle; determining whether or not a preceding vehicle is among the at least one object present in front of the controlled vehicle; controlling the vehicle travel speed according to a set distance to the preceding vehicle in a distance control mode when the preceding vehicle is present in front of the controlled vehicle; establishing whether or not a stationary object is among the at least one object present in front of the controlled vehicle; when a stationary object is found to be present, calculating a predicted travel path of the controlled vehicle and determining if the stationary object is located in the predicted travel path; w

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: This FM-CW radar apparatus comprises a transmitter section, a receiver section, and a signal processing section. The transmitter section transmits a frequency-modulated continuous wave as a transmitted wave. The receiver section receives a radio wave resulting from reflection of the transmitted wave at a target, as a received wave, by a receiving antenna comprising an array of antenna elements, generates a beat signal which is a difference of the transmitted wave and the received wave in each of channels of the respective antenna elements, and converts this beat signal to a digital beat signal by A/D conversion. The signal processing section executes a digital beamforming operation with the digital beat signals and detects the target from the result of the operation.

Abstract: A device for changing the divergence of a beam of microwave radiation comprises a ferrite body having an aperture through which the beam passes. Magnetic wires pass both through the body and across the aperture, or a magnetic coil on either side of the aperture, causes a differential phase delay as the beam passes through the aperture which broadens or narrows the beam.

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: A pseudo-noise-modulated spread spectrum is irradiated undirectedly--or, encoded by different modulation, into mutually displaced spatial sectors--and the energy (20) received after reflection at a potential target (13) is cross-correlated, using the pseudo-noise code which is predetermined at the transmission end, in order to provide a spherical monitoring effect which is continuous but which cannot be located in respect of its origin, to provide a warning in particular for marine craft, land vehicles and aircraft against an attacking guided missile as the target (13) to be repelled, and in order to be able to transfer to a target tracker (12) distance and speed information obtained from the correlation product, with the alarm signal, if the alarm sensor (11) is not itself also used as the tracking sensor.

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 process for determining the distance between a distance sensor and an object, wherein an analog input signal is directed to a transmitter of the distance sensor. The transmitter emits a wave which is reflected by the object. A receiver of the distance sensor receives the reflected wave and thereupon emits an analog output signal whose level is dependent upon the distance and/or the type of object. The output signal is amplified by a subsequently added amplifier. The amplifier signal is directed to an analog/digital converter and is converted into a digital signal. The digital signal is directed to an evaluation circuit for the computation of a distance value. The signal amplification of the amplifier is controlled in an adaptively dependent manner on the level of the output signal and/or in a manner dependent on the signal value of an amplification signal made available by the evaluation circuit which is characteristic of an anticipated distance range.

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: An apparatus and techniques for correlating crossing targets in an air traffic control system is described. The technique utilizes a target/track correlation made on the basis of three conditions: (1) separation distance between a target pair; (2) target polarity and (3) a value of a threshold separation value indicator.

Abstract: The objectives of the invention are met by an improved radar tracking system and a process of radar tracking. In the improved system and process, an estimate of a target range and a range uncertainity swath from a first radar system is inputted into a second radar system along with a duty factor. The second radar system determines a set of zero eclipse intervals and respective ranges of range pulse repetition frequencies that solves a first set of equations. A usable range pulse repetition frequency is chosen from the results. Next, an estimated target Doppler frequency region and a Doppler uncertainity swath is inputted into the second radar system. The second radar system is instructed to determine a set of clear Doppler frequency region intervals, and respective ranges of Doppler frequency pulse repetition frequencies by solving a second set of equations.

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: When a transmitted and received radio wave is scanned, even if, for example, a large vehicle is running on an adjacent lane, a preceding vehicle running on the same lane as an own vehicle can be sensed and tracked continually. An on-vehicle radar comprises a transmitter receiver 6 for transmitting and receiving a radio wave with a relatively high frequency, and a signal processor 10 calculating a relative distance to an object and a relative velocity of the object on the basis of a radio wave transmitted by the transmitter receiver, reflected from the object, and received by the transmitter receiver.

Abstract: An automatic object responsive control system for a work implement has a ground penetrating device mounted for sensing subsurface objects, an object detecting device for determining the undesirability of the object, and an implement control system for automatically elevationally raising the implement in response to an undesirable object being located elevationally between the implement and the ground penetrating device. The automatic object responsive control system is particularly suited for use on a geographic surface altering machine.

Abstract: A radar system operating by the line-of-sight method requires an accurate measurement of the relative position of at least two objects. By sending out coded radar transmission pulses, control data are transmitted to a guided flying body in a radar beam, which sends back an echo signal to the receiver via a transponder. In order to measure the passive signal and the transponder echo signal in the radar beam as accurately as possible, common reception channels are provided for both echo signals containing, inter alia, arrangements to equalize the dynamic levels of the echo signals. The returned transponder echo signal corresponds with respect to coding and bandwidth to the transmission pulses originally generated in the transmitter and that are phase-coded but not provided with the control code.

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: Improved non-cooperative radar apparatus locates and type-classifies an agitated, vibrating reflective target (e.g., a vehicle with its engine running) - whether the target is moving or stationary.A homodyne-type receiver with a cooperating band pass filter extracts a reflected, frequency-shifted energy pattern which identifies the incidence of the agitated target. In accordance with further aspects of the instant invention, the particular energy distribution for the returned, reflected wave is then compared with a stored ensemble of such distributions, or target "signatures", to type-catagorize the target.

Abstract: Improved non-cooperative radar apparatus locates and type-classifies an agitated, vibrating reflective target (e.g., a vehicle with its engine running)--whether the target is moving or stationary.A homodyne-type receiver with a cooperating band pass filter extracts a reflected, frequency-shifted energy pattern which identifies the incidence of the agitated target. In accordance with further aspects of the instant invention, the particular energy distribution for the returned, reflected wave is then compared with a stored ensemble of such distributions, or target "signatures", to type-categorize the target.