Abstract: A weather radar system coupled to a weather radar antenna, including a receive circuit for receiving radar returns received by the antenna and a processor for summing portions of the radar return data to obtain a null response. The null response is utilized to determine presence of terrain.

Abstract: A method, system and computer program is disclosed for reducing range and angular ambiguities in a target data matrix output from a real beam monopulse radar sensor within a single beam for use in terrain morphing applications employed by brownout take-off and landing aid systems. One or more range bins are calculated to selectively determine one or more range segments from one or more targets of interest. Range resolution enhancement processing is employed to the selectively determined one or more range segments to obtain a range of target scatter locations. A monopulse angle bin is estimated from the obtained range of target scatter locations and one or more control inputs. Elevation and azimuth angular binning is applied to the estimated monopulse angle bin to obtain a smaller coverage area among one or more possible target areas.

Abstract: In an azimuth detecting apparatus, a receiver includes antenna elements arranged at predetermined intervals d. A first signal producer produces, based on reception signals generated by the antenna elements, first signals which are equivalent to signals generated by antenna elements arranged at first intervals d1, d1 being an integral multiple of d. A second signal producer produces, based on the reception signals, second signals which are equivalent to signals generated by antenna elements arranged at second intervals d2, d2 being an integral multiple of d and greater than d1. A first azimuth detector detects, within a first azimuth detection area whose angular range is defined by d1, the azimuth of the target based on the first signals. A second azimuth detector detects, within a second azimuth detection area whose angular range is defined by d2, the azimuth of the target based on the second signals.

Abstract: A frequency converter for a filling level radar includes a signal generator unit, a receiver circuit, a transmit coupler, and an amplifier. The amplifier is amplifying the transmit signal at the high frequency side of the frequency converter. For frequency conversion, a mixer or a multiplier may be provided.

Abstract: A collision avoidance system for reducing false alerts by estimating the elevation of a target, includes short and long range single-dimensional scanning radar sensors having differing ranges and beam angles of inclination, and a digital fusion processor, and preferably includes a locator device, an inclinometer, and a memory storage device cooperatively configured to further perform trend analysis, and target tracking.

Abstract: The invention relates to an apparatus for finding a parked vehicle again. According to the invention, a portable unit is provided with a pressure sensor whose signals can be evaluated by an evaluation and control unit in order to determine the current air pressure, with the evaluation and control unit evaluating the determined air pressure in order to determine altitude, and storing a first air pressure value as a reference value at a predeterminable first time, which reference value represents an instantaneous altitude of a geographic position of the parked vehicle, with the evaluation and control unit estimating a height difference between a current geographic position of the portable unit and the geographic position of the parked vehicle at a second time, and/or continuously from a pressure difference between the determined current air pressure value and the reference value.

Abstract: A method for compensating for range gate slide with respect to received returns within a radar altimeter is described. The method includes adjusting the amount of overlap between a range gate pulse and a radar return signal until an altitude output by the radar altimeter is within a desired tolerance, and incrementally increasing an amount of attenuation within the receiver circuit of the radar altimeter until the radar altimeter breaks track with the radar return signal. the method also includes recording a signal strength and altitude output at each increment of attenuation, determining an altitude error for each altitude output, and fitting the signal strength data against the altitude error using a plurality of variable length line segments.

Abstract: A height-finding 3D avian radar comprises an azimuthally scanning radar system with means of varying the elevation pointing angle of the antenna. The elevation angle can be varied by employing either an antenna with multiple beams, or an elevation scanner, or two radars pointed at different elevations. Heights of birds are determined by analyzing the received echo returns from detected bird targets illuminated with the different elevation pointing angles.

Abstract: Method and apparatus to track a contact using a sensor in a two-dimensional radar system, determine a closest point of approach (CPA) for the contact, determine a time to closest point of approach (TCPA) for the contact, and estimate an altitude for the contact from the closest point of approach (CPA) and a cross line of sight distance during the time to closest point of approach (TCPA).

Abstract: A system is for recognizing obstructions and monitoring movements on or above an airport area (1) with sensors (2, 3, 4). A sensor (2) is a radar device having a plurality of antenna elements (12, 14), which are affixed to a curved surface (15) of an antenna carrier (2a) and are turned on, one after the other, in terms of time. Thus a first part of the antenna elements (14) is disposed on a first circular line (13) on the surface of the antenna carrier (2a), and a second part of the antenna elements (12) is disposed on a circular line (15) perpendicular to the first circular line (13). Therefore the data of the radar device (2) are evaluated in a first ROSAR process, to image the situation on the ground, and in a second ROSAR process, to image the heights of the flying objects to be observed.

Abstract: Method and apparatus to track a contact using a sensor in a two-dimensional radar system, determine a closest point of approach (CPA) for the contact, determine a time to closest point of approach (TCPA) for the contact, and estimate an altitude for the contact from the closest point of approach (CPA) and a cross line of sight distance during the time to closest point of approach (TCPA).

Abstract: A pulse detection system for expanded time radar, laser and TDR sensors detects specific cycles within bursts of cycles. A sensor transmits and receives short bursts of RF cycles. A transmit pulse detector triggers on a selected cycle of the detected transmit burst and starts a range counter. A receive detector triggers on a selected cycle within a received echo burst to stop the range counter, thereby indicating range. Cycle selection is enabled by an analysis window of time. The detection system can provide accuracies on the order of one picosecond and is well-suited to accurate ranging along an electromagnetic guide wire.

Abstract: A method of characterizing a maximum height of a storm cell for an aircraft is provided. First reflectivity data formed from a first scan of a storm cell by a radar is received and a first centroid of the storm cell is identified. Second reflectivity data formed from a second scan of the storm cell by the radar is received and a second centroid of the storm cell is identified. A scan axis for a third scan of the storm cell based on the first centroid and the second centroid is determined. Third reflectivity data formed from the third scan of the storm cell by the radar at a first time is received. The third reflectivity data is sampled to form pixel data that includes a reflectivity indicator determined for each pixel formed from the third reflectivity data. A maximum height of the storm cell is determined by processing the pixel data.

Abstract: The invention discloses a device for using radar signals to measure the vertical distance (h) to a surface, comprising a first transmitter and a first transmitting antenna for transmitting radar signals, and a first receiver and a first receiving antenna for receiving radar signals. The device additionally comprises a second receiving antenna and a second receiver, the second receiving antenna being arranged at a first predetermined horizontal distance (?x) from the first receiving antenna, the device also being equipped with means for using signals which have been transmitted from the first transmitting antenna and received at the first and second receiving antennas to calculate the vertical distance to the surface. Suitably, the first and second receivers are one and the same physical unit, to which both the first and the second receiving antennas are coupled.

Abstract: Apparatus and a method utilizing correlation interferometer direction finding for determining the azimuth and elevation to an aircraft at long range and flying at low altitudes above water with a transmitting radar while resolving multipath signals. The signals from the radar are received both directly and reflected from the surface of the water using horizontally polarized and vertically polarized antenna arrays, are digitized and are stored in separate covariant matrices. Eigenvalues for the eigenvectors of the matrices processed on signal samples recorded on horizontally polarized X arrays are compared to the eigenvalues for the eigenvectors of the covariance matrices processed on signal samples recorded on vertically polarized X arrays. Incident field polarization is associated with the antenna array measurements that yield the strongest eigenvalue. The eigenvector and eigenvalues for the strongest signal are selected and used for subsequent signal processing.

Abstract: A method for determining a mechanical angle to a radar target utilizing a multiple antenna radar altimeter is described. The method comprises receiving radar return signals at the multiple antennas, populating an ambiguity resolution matrix with the electrical phase angle computations, selecting a mechanical angle from the ambiguity resolution matrix that results in a least amount of variance from the electrical phase angle computations, and using at least one other variance calculation to determine a quality associated with the selected mechanical angle.

Abstract: A method for determining the height HT of a target above a surface, the method comprising the steps of determining a distance R from a source to a target, determining a distance L representative of a distance traveled by a signal from the target that is reflected by the surface to the source, determining a height H of the source above the surface, and determining the height HT of the target using the equation: H T = ( L 2 - R 2 ) 4 ? H Associated target height errors that result from input errors can also be determined using the equation.

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 synthetic aperture radar system uses RF bandwidth and Doppler beam sharpening principles to develop fine altitude and along-track resolutions. To achieve accurate cross-track position measurements the system and method exploit a combination of modes based on a novel antenna pattern combination. The unique arrangement of the antenna patterns allows the radar to process terrain elevation measurements in three independent modes, namely, time-delay response (TDR), amplitude monopulse (AM) and phase monopulse (PM). The additional modes address the interfering scatter problem and the calibration issues required for practical and cost effective operation. The approach also maximizes the number of terrain measurements made per look, thereby reducing the impact of errors and noise through averaging and “voting” (i.e., the comparison of measurements and discarding of “outliers”).

Abstract: System and method for determining the height of an object reflecting a real beam radar signal by receiving the reflected signal with a first and second vertically spaced antennas. Receivers provide two signals indicating the phase of the reflected signals received by the two antennas. A digital processor determines the phase difference between the two signals and calculates the object height.

Abstract: A system and method for determining the slope of a ground imaged area. The system includes a camera, a memory, and a processor. The camera generates a first and a second image of an area of ground from an aircraft. The memory stores bi-directional characteristic information for associated materials. The processor determines a material type associated with a plurality of the pixels based on a color value of the pixels. The processor retrieves bi-directional characteristic information from the memory for a pixel based on the determined material type. A slope value at a pixel location is determined based on the associated viewing angle values, a determined radiance change value, and the retrieved bi-directional characteristic information.

Abstract: A method for randomly phase modulating a radar altimeter is described. The method includes momentarily applying a signal from a random noise source to an amplifier, applying an output of the amplifier to a voltage controlled oscillator (VCO), applying an output of the VCO to a transmitter and mixer of the radar altimeter to modulate transmissions of the radar altimeter and to demodulate reflected radar transmissions received by the radar altimeter and holding the output of the amplifier constant from before a radar altimeter transmission until after reception of the reflected radar signals from that transmission by the radar altimeter. The method further includes repeating the applying steps and the holding step.

Abstract: A method and apparatus for estimating elevation angle when using a broad search beam such as a cosecant-squared beam is provided. The range of a target detected during a search with a broad beam covering a broad angular search area is determined. Based on the determined range, consecutive beams are transmitted at increasing search elevation angles in the broad angular search area. Echo signals of the consecutive beams are used to determine an elevation angle estimate for the target.

Abstract: A radar altimeter for vehicles that operate with a load suspended underneath is described. The radar altimeter includes a transmitter configured to transmit radar signals toward the ground, a receiver configured to receive reflected radar signals from the ground and from the suspended load, and at least one altitude processing channel configured to receive signals from the receiver. The radar altimeter also includes a load profile channel configured to receive signals from the receiver. The load profile channel limits an altitude processing sensitivity of the radar altimeter between the radar altimeter and the suspended load to reduce a likelihood that the radar altimeter will process signals reflected by the suspended load.

Abstract: In a method and system to determine the position of a target by means of an IFF type antenna, the antenna having a given direction of aim, the method comprises a step for combining the distance D from the target to the carrier, the altitude A of the target, the altitude Apf of the carrier equipped with the IFF antenna and the angular error value of the target and the direction of aim of the antenna beam to localize the target with precision. Application to IFF interrogations in mode C.

Abstract: A multi-antenna, multi-pass IFSAR mode utilizing data driven alignment of multiple independent passes can combine the scaling accuracy of a two-antenna, one-pass IFSAR mode with the height-noise performance of a one-antenna, two-pass IFSAR mode. A two-antenna, two-pass IFSAR mode can accurately estimate the larger antenna baseline from the data itself and reduce height-noise, allowing for more accurate information about target ground position locations and heights. The two-antenna, two-pass IFSAR mode can use coarser IFSAR data to estimate the larger antenna baseline. Multi-pass IFSAR can be extended to more than two (2) passes, thereby allowing true three-dimensional radar imaging from stand-off aircraft and satellite platforms.

Abstract: A transponder having a subsystem for providing an altitude alert function signifying a deviation from a set altitude is described. The subsystem includes an input for receiving an altitude deviation limit associated with the set altitude, a CPU receiving updated altitude and determining a difference between the updated altitude and the set altitude associated with the altitude deviation limit, and a transponder subsystem output device for providing the difference between the updated altitude and the set altitude to a user.

Abstract: A synthetic aperture radar system uses RF bandwidth and Doppler beam sharpening principles to develop fine altitude and along-track resolutions. To achieve accurate cross-track position measurements the system and method exploit a combination of modes based on a novel antenna pattern combination. The unique arrangement of the antenna patterns allows the radar to process terrain elevation measurements in three independent modes, namely, time-delay response (TDR), amplitude monopulse (AM) and phase monopulse (PM). The additional modes address the interfering scatter problem and the calibration issues required for practical and cost effective operation. The approach also maximizes the number of terrain measurements made per look, thereby reducing the impact of errors and noise through averaging and “voting” (i.e., the comparison of measurements and discarding of “outliers”).

Abstract: An improved method of estimating target elevation angle for dual squinted beam radar systems is disclosed. The target's elevation angle is estimated by receiving complex I/Q data from two receive radar beams and calculating the complex ratio of the complex I/Q data. The calculated complex ratio is compared to a set of previously determined reference complex ratios in complex lookup tables that have been corelated to known target elevation angles.

Abstract: Stableness in detecting the distance to a preceding vehicle by calculating the distance to the preceding vehicle using reflected waves of a radar beam scanned at a scanning angle that is adjusted based on lane markers extracted from a road image obtained by a camera.

Abstract: A method and apparatus for determining the distance between an agricultural machine and a surface such as the ground, wherein at least one sensor contactlessly determines the distance between the sensor and the surface. The sensor uses electromagnetic waves to penetrate through the field vegetation. The sensor may be a radar, a microwave or a laser sensor. The electromagnetic wave is emitted in a vertical direction toward the ground and reflected back to the sensor. The determined distance is used for automatically maintaining a working height of a front attachment, such as a cutterbar.

Abstract: Multiple radar altimeters on a constellation of individual satellites in the same orbit plane relate an advanced ocean altimetry system. Earth rotation separates the respective measurement tracks of each satellite on the ocean surface. Each satellite can host a monostatic radar altimeter, which may contain a co-located transmitter and receiver that generates one surface track of ocean height measurements at nadir. Further, each satellite payload can include a bistatic radar altimeter, comprising a transmitter and a receiver located respectively on neighboring satellites. The bistatic altimeter comprises a virtual nadir altimeter that generates an additional surface track of ocean height measurements along the locus of midpoints on the surface between the satellites' nadir points.

Abstract: Stableness in detecting the distance to a preceding vehicle by calculating the distance to the preceding vehicle using reflected waves of a radar beam scanned at a scanning angle that is adjusted based on lane markers extracted from a road image obtained by a camera.

Abstract: A system and method for identifying the position of an airborne platform on a flight path includes at least three radar transceivers that are directed along respective beam paths to generate return signals. Each of the return signals respectively indicate a speed and a direction of the platform relative to points on the surface of the earth. A computer uses the return signal to establish a ground speed, an altitude and a direction of flight for the platform. This information is then used to identify the position of the platform on its flight path. Additionally, the system can include a last known position, or a site-specific radar clutter model, to establish a start point for the platform. The computer can then calculate the position of the platform relative to the start point.

Abstract: Environment measurement methods, systems, media, signals and data structures are disclosed. A first method involves receiving first signals produced in response to a laser beam scattered by the environment, receiving second signals produced in response to a radar beam scattered by the environment, and storing data representing the first and second signals, for use in producing a representation of the environment. A second method involves continuously producing data in response to scattered portions of a laser pulse scattered by respective portions of the environment, during a measurement interval of sufficient duration to receive all the scattered portions, and storing the data, for use in producing a representation of the environment.

Abstract: An arrangement for the precise measuring of the distance with a FMCW radar device having a frequency-variable digitally-actuated oscillator to generate a transmitting frequency which can be tuned over a predetermined frequency range. The digital actuation involves the use of a digital frequency generator which derives in predetermined frequency steps a references signal from a fixed-frequency oscillator signal. The frequency of the frequency-variable oscillator is adjusted in a phase-locked loop linking it to the references signal.

Abstract: A target 22 is explored by transmitting an exploration signal 40 at a certain angle while scanning an antenna 23. In the go and return exploration the angle for transmitting the exploration signal is shifted. It is possible to detect the direction of the target 22 with the same accuracy as that in exploration with a more minute angle difference, by combining the exploration results with the angle shifted in a plurality of scans. Relative travel of the target 22 that accompany a plurality of scans is considered as a Doppler shift and a combination of data is used considering the frequency shift. Data that cannot be combined is treated as an unwanted reflective object and the position where unwanted reflecting objects assemble is obtained and the position is determined as a shoulder. The height of a stationary target is determined from the variation in the reflected signal level in an approach to the stationary target.

Abstract: An apparatus for determining the relative height between two targets is disclosed. The present invention also discloses a method for determining the relative height between two targets; the method is substantially similar to the operational aspects of the device of the present invention. The method requires no angular measurements in order to determine the different height between the two targets, but rather only distance measurements that can be performed simply and accurately. The apparatus for determining the relative height between two targets a disclosed.

Abstract: A single-antenna short-range radar transceiver emits 24 GHz RF sinewave packets and samples echoes with strobed timing such that the illusion of wave propagation at the speed of sound is observed, thereby forming an ultrasound mimicking radar (UMR). A 12 GHz frequency-doubled transmit oscillator is pulsed a first time to transmit a 24 GHz harmonic burst and pulsed a second time to produce a 12 GHz local oscillator burst for a sub-harmonically pumped, coherently integrating sample-hold receiver (homodyne operation). The time between the first and second oscillator bursts is swept to form an expanded-time replica of echo bursts at the receiver output. A random phase RF marker pulse is interleaved with the coherent phase transmitted RF to aid in spectrum assessment of the radar's nearly undetectable emissions.

Abstract: For a radar device arranged above a reflecting surface, a method is suggested for estimating the height of an object above the surface. This method does not require a refined angle resolution for the radar antenna and is based solely on the processing of signals. The invention makes use of the appearance of an interference pattern for the radiation field of the radar antenna, which normally is viewed as a disadvantage, by evaluating the intensity modulation of a signal received from an object moving in radial direction to the radar device within the surveillance range. Together with the measured distance to the object, this is used to estimate a value for the height of the object above the road surface.

Abstract: The stopping of a load suspended from a crane requires a swing control or, respectively, a swing damping. Upon employment of microwave measuring units, spacings between a carrying cable suspension and a load suspension point are determined on the basis of transit time measurements. The position of the load suspension point can be determined from the transit time measurements quickly and with high precision. Swinging motions are avoided by controlled opposing control of the carrying cable suspension.

Abstract: A positioning and ground proximity warning method for vehicle includes the steps of outputting global positioning system signals to an integrated positioning/ground proximity warning system processor; outputting an inertial navigation solution to an integrated positioning/ground proximity warning processor; measuring air pressure, and computing barometric measurements which is output to the integrated positioning/ground proximity warning processor; measuring time delay between transmission and reception a radio signal from a terrain surface, and computing radio altitude measurement which is output to the integrated positioning/ground proximity warning processor; accessing a terrain database for obtaining current vehicle position and surrounding terrain height data which is output to the integrated positioning/ground proximity warning processor; and receiving the position, velocity and time information or said pseudorange and delta range measurements of said global positioning system, the inertial navigation s

Abstract: An equivalent time pulse-echo radar or other pulse-echo system employs a transmit reference sampler collocated with the transmitter to provide a transmit reference pulse, which initiates a pulse width modulated (PWM) pulse. A receive sampler connected to a receive antenna provides an echo-detection pulse that terminates the PWM pulse, such that the width of the PWM pulse indicates target range. The transmit reference sampler and the receive sampler are driven from a common clock such that transmit-receive timing offset drift precisely cancels on a picosecond scale, thereby enabling sub-mm range accuracy with common, low-cost circuit elements. The radar further includes automatically referenced pulse detectors that are responsive to either the magnitude or the phase of the sampler outputs. The radar can be used for precision tank level measurements, robotics, or automotive ranging applications.

Abstract: Radar is used to measure not only the level of slag on molten steel but also its thickness; the measurement is used to calculate the volume of slag, and, in turn the amount of additives for slag treatment.

Abstract: An altimetric type measurement method for use on a satellite transmits a pulse towards the surface of the sea and carries out frequency transformation on the return signal resulting from the reflection of this pulse at the surface of the sea. This produces a spectral signal of samples successively comprising:(a)--a first zone with a low amplitude level,(b)--a second zone with a sharply increasing slope ending at a peak, and(c)--a third zone of decreasing slope.Samples of the spectral signal are selected within a selection zone that corresponds to the first and second zones for a predetermined maximal level of the height of the waves at the surface of the sea and maximum likelihood processing is applied only to the selected samples.

Abstract: An apparatus for measuring the height and cross-track offset of a surface location from a moving platform is defined. First and second antennas positioned on an underside of the platform are directed downwardly toward the surface. A transmitter associated with one of the antennas transmits a signal toward the surface. A first coherent detector associated with the first antenna detects a received signal corresponding to the transmitted signal as reflected by the surface and generates in-phase and quadrature components of the detected signal relative to the transmitted signal. A second coherent detector associated with the second antenna detects a received signal corresponding to the transmitted signal as reflected by the surface and generates a second set of in-phase and quadrature components of the detected signal relative to the transmitted signal. An analog to digital (A/D) converter converts the in-phase and quadrature components into digital information stored in a memory.

Abstract: A method for measuring the height of an aircraft above a target. An aircraft or platform is provided with a synthetic array radar (SAR) system that is used to designate a target. The aircraft performs a constant g vertical maneuver followed by a second constant g vertical maneuver whose incremental acceleration is equal in magnitude to the first maneuver and has opposite sign. The maneuvers are out-of-plane relative to a plane containing the velocity vector of the aircraft and the target. The maneuvers correspond to a push-over maneuver followed by a pull-up maneuver. SAR map data is collected during the maneuver that includes the designated target. Quadratic phase errors contained in the collected SAR map data are measured. The height of the target relative to the ground plane of focus of the SAR system is computed using the quadratic phase errors.

Abstract: A method of detecting the displacement of a target in a given environment includes storing reference data having data representative of the environment; transmitting a transmit signal towards the target; sensing the return signals from the target and the environment; and detecting the displacement of the target by comparing the return signals and the stored reference data. A method of detecting the level of a sample in a container is also disclosed. Analogous apparatus features are also disclosed.

Abstract: Transmitted signals are used to accurately and remotely determine the veral distance of an earth-based receiving antenna above a surface, and hence can be used to determine the tide condition of a water surface. A signal is transmitted from a signal source as it moves either through air or space. An antenna whose height is to be determined with respect to a reflecting surface, such as water, receives the signal directly from the signal source and indirectly from the signal source by reflection of the signal from the reflecting surface. The sum of the directly and indirectly received signals form an interference pattern as the signal source is moved. Points on the interference pattern are selected at identical phase angle for each cycle of the pattern. The points are assigned reference numbers and the numbers are plotted with respect to a measurement indicative of the distance between the signal source and the antenna whose height with respect to the reflecting surface is to be determined.

Abstract: An enhanced system for calculating the Z-Axis, or relative height or altitude, of a radio beacon. The present invention uses a barometric pressure sensing device co-located with the radio emitter to transmit data representing relative altitude. To further enhance the Z-Axis determination, one or several barometric sensors, located at known heights, are positioned around the city to provide real time barometric data. This real time data is used to form a differential correction factor which is compared to the to the time varying barometric sensor co-located with the radio emitter, thereby yielding Z-Axis accuracies of up to one (1) foot. Since the altitude essentially becomes a "known", this information can also be used in the least squares fit algorithm to enhance the X and Y determination as well.