Abstract: The microwave measuring device, which preferably operates with microwave bursts, serves to produce a measured value (XH) representing the level of the contents of a vessel (200). It comprises a transceiver unit (2) for generating a level-dependent intermediate-frequency signal (ZF) by means of a transmit signal (S2) and a receive signal (E2), and a transducer element (1) which in operation couples waves (S1), particularly pulsed waves, into the vessel under control of the transmit signal (S2) and converts echo waves (E1) reflected from the contents (201) of the vessel into the receive signal (E2). The intermediate-frequency signal (ZF) is fed to a control unit (3) of the level measuring device where it is stored in the form of a sampling sequence (AF) in a volatile data memory (33). In this manner, both amplitude information and phase information is available for the level measurement. The device is thus capable of measuring level with high accuracy, particularly accurately to a millimeter, and very fast.

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: A method, system, and computer program product for storing weather radar return data into a three-dimensional buffer. The system includes a radar system that transmits a radar signal and generates a radar measurement as a result of radar return of the transmitted radar signal. A three-dimensional buffer includes a plurality of storage locations. A processor is coupled to the radar system and the buffer. The processor generates or updates a reflectivity value in storage locations in the three-dimensional buffer based on the generated radar measurement, a previously stored reflectivity value for the storage location, and at least one of an uncertainty value for the storage location. The generated reflectivity value is stored in the three-dimensional buffer according to the storage location.

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: For interferometric and/or tomographic remote sensing by means of synthetic aperture radar (SAR) one to N receiver satellites and/or transmitter satellites and/or transceiver satellites with a horizontal across-track shift the same or differing in amplitude form a configuration of satellites orbiting at the same altitude and same velocity. Furthermore, a horizontal along-track separation, constant irrespective of the orbital position, is adjustable between the individual receiver satellites. In this arrangement one or more receiver satellites orbiting at the same altitude and with the same velocity are provided with a horizontal across-track shift varying over the orbit such that the maximum of the horizontal across-track shift occurs over a different orbital position for each satellite, the maxima of the horizontal across-track shifts are positioned so that the baselines are optimized for across-track interferometry.

Abstract: A system for reducing multi-path reflections from adjacent metal objects which cause distortion in an IFSAR includes a reflective cone extending between the top of the IFSAR and the skin of its aircraft, and a reflective shroud surrounding the IFSAR. Each of these components may be coated with radar absorbing material.

Abstract: An imaging system and method. The invention provides an intra-pulse repetition interval (PRI) agile beam technique for enhanced resolution that can be used at aspect angles near the velocity vector of a host vehicle. It is particularly useful at small scan angles where beam sharpening array times become large. At these scan angles, the bandwidth of the clutter is narrower than at higher scan angles and allows large PRIs without degradation from Doppler ambiguities. In accordance with the present teachings, sequential illumination is performed within a PRI to multiple beam locations using an agile beam. The interleaving of beams reduces map formation times compared to conventional techniques using sequential arrays. The inventive system is adapted for use with an electronically scanned (e.g., synthetic aperture array radar) antenna.

Abstract: An imaging system and method. The invention provides an intra-pulse repetition interval (PRI) agile beam technique for enhanced resolution that can be used at aspect angles near the velocity vector of a host vehicle. It is particularly useful at small scan angles where beam sharpening array times become large. At these scan angles, the bandwidth of the clutter is narrower than at higher scan angles and allows large PRIs without degradation from Doppler ambiguities. In accordance with the present teachings, sequential illumination is performed within a PRI to multiple beam locations using an agile beam. The interleaving of beams reduces map formation times compared to conventional techniques using sequential arrays. The inventive system is adapted for use with an electronically scanned (e.g., synthetic aperture array radar) antenna.

Abstract: A system and method for imaging objects obscured by a covering layer of snow. The system preferably utilizes a continuous-wave radar generating short-wavelength radio-frequency (RF) signal beam-scanned over angular displacements following a scanning pattern toward a target area. Reflections of the:RF signal from objects buried beneath the snow are registered by an array of RF detectors whose signal magnitudes are summed arid correlated with scan direction to generate a signal providing spatial object information, Which by way of example, is visually displayed. The radio-frequency beam may be scanned over the scene electronically or by either mechanically or electromechanically modulating antenna direction or the orientation of a beam deflector. The system is capable of generating multiple image frames per second, high-resolution imaging, registration of objects to a depth exceeding two meters, and can be implemented at low cost without complex signal processing hardware.

Abstract: A bistatic radar system and method. In the illustrative embodiment, a receiver is positioned in a horizontal plane. A transmitter is then positioned in Middle Earth Orbit at a position that is nearly vertical to the plane of the receiver. This configuration provides significant flexibility for the radar system. As such, the radar system may engage in flight patterns, in which the transmitter and receiver have velocity vectors in opposite directions (GMTI mode), the same direction (SAR mode) and variations in between (mixed mode). Lastly, a broad beam is generated from the transmitter and illuminates an area enabling several receivers to simultaneously observe the illuminated area.

Abstract: The present invention comprises a scanner or imager that employs a plurality of ultra-wideband (UWB) transmitters that emit a multiplicity of UWB pulses, which are received by a plurality of receivers. An object or person positioned between the UWB transmitters and receivers can be scanned and subsequently imaged in extreme detail, due to the broad spectral content of the UWB pulses. The UWB scanner can be constructed as a stationary or portable device.

Abstract: A multi-channel digital equivalent time sampling (MDETS) device having a programmable logic control that can select, delay or create various triggered signals. The MDETS can function independently or with multiple devices allowing for synchronized acquisition of data. The close proximity of MDETS device to a transmitter and receiver allows for the short time delay for acquiring the data.

Abstract: From a body located at a distance above the surface of the earth, an image is recorded of a region that is located underneath the body on or above the surface of the earth and that has a diameter of at least one kilometer. The recorded image is fully geocoded and comprises a grid dimension small enough that vehicle densities located in the region can be recognized. The recorded image is evaluated with respect to these vehicle densities and the spatial allocation thereof to the associated roadways. The method is used for acquisition of the state of street traffic over a large area.

Abstract: The present invention relates to a radar system which comprises a platform which moves over a number of objects. The number of objects can be very large and the objects can appear in the form of, for example, a ground surface. The platform supports radar equipment which reproduces the objects by means of synthetic aperture technique (SAR) via at least one antenna without requirements as to directivity or fractional bandwidth. Moreover, the movement of the platform is, during the recording of data for a SAR image, essentially rectilinear and uniform. The invention is characterized mainly in that it comprises a signal-processing device which records received radar echoes from each transmitted radar pulse and records or calculates the position of the used antenna or antennae, and which calculates a one-parameter quantity of two-dimensional SAR images as a function of two image co-ordinates where the parameter is the relative speed. Here use is made of the fact that each object, i.e.

Abstract: An improved multi transducer for a ground penetrating radar system (GPR) having a complete circuit for internal timing of signal emission, detection, digitalization and recording of data.

Abstract: A radar (300) comprises a transceiver (302) for transmitting pulses directed to a subsurface area of interest (102) and for receiving a reflected wave (210) from the subsurface area of interest. The pulses have a pulse duration and amplitude constrained by the equation, d2|E|e/m≦1 Angstrom, where d is the pulse duration in seconds, E is the pulse amplitude in volts/meter, e equals the charge of an electron in Coulombs, and m equals the mass of an electron in Kg. A processing device (304), in communication with the transceiver, processes the reflected wave and displays an image of the subsurface area of interest and identifies the material composition of subsurface objects that have known properties that vary as a function of the pulse duration and amplitude.

Abstract: The present invention relates to a radar video display and recording device, which can simultaneously display radar video signals of the whole and designated areas in the polar coordinates and Cartesian coordinates, respectively, and can store the radar video signals of the designated area in a hard disk drive (HDD) for obtaining long-time continuous radar video information for subsequent analysis and algorithm verification. A radar video capture card is utilized on a personal computer (PC) or workstation platform to analyze and store radar video signals of the whole and designated areas and to simultaneously display video signals at different processing stages in a digital video processing unit on a scope for monitoring the work condition at each processing stage.

Abstract: A Radon transform based method that provides for target azimuth aspect estimation and target shape measurement. A Radon transform is applied to a binary (N×N pixels) target chip to extract target features that are then used to measure length, width, and diagonal features of the target. In parallel, these features are used to estimate the azimuth aspect angle, or size, of the target. The method is effective in discriminating targets from clutter. The method is also very time efficient and highly flexible in its operation because the features can automatically account for any target rotation or shift. The present invention also provides for a target acquisition system that employs the Radon transform based method for target azimuth aspect estimation.

Abstract: A synthetic aperture radar system fluctuation compensating apparatus includes a synthetic aperture radar mounted on a flying unit, a data acquiring unit, a position measuring unit and a position determining unit. The data acquiring unit receives a reception data by the synthetic aperture radar. The position measuring unit measures a position of the flying unit to generate a position data. The position determining unit determines a correct position of the flying unit based on the reception data and the position data to generate a compensated position data.

Abstract: The invention relates to a method for monitoring the earth's surface with a moving aircraft using a radar sensor with a synthetic aperture. In order to produce high resolution radar images, the flight parameters of the aircraft are also required. According to the inventive method, key parameters, such as speed and acceleration, are detected in the sight line of the radar sensor from the radio signals received. One of the advantages of the invention is that an inertial navigation system (INS) is no longer required for this purpose.

Abstract: Interferometric synthetic aperture radar (IFSAR) is a promising technology for a wide variety of military and civilian elevation modeling requirements. IFSAR extends traditional two dimensional SAR processing to three dimensions by utilizing the phase difference between two SAR images taken from different elevation positions to determine an angle of arrival for each pixel in the scene. This angle, together with the two-dimensional location information in the traditional SAR image, can be transformed into geographic coordinates if the position and motion parameters of the antennas are known accurately.

Abstract: An apparatus and method for imaging uses a transducer array which receives a scattered signal from a region of interest. The method analyses the scattered signal on the basis of a model which assumes several independent point scatterers at each range. The method determines the amplitudes and angles of arrival for the several scatterers. The method provides much higher resolution than is possible with conventional beam formed sonar arrays of practical size. The method is capable of resolving features which cannot be resolved by conventional sidescan sonar or interferometric side scan sonar. The method may be used with electromagnetic or acoustic scattering signals.

Abstract: A method of phase unwrapping is described along with an efficient UNIX/C implementation. From selected reference or starting points in a phase-wrapped image, the phase gradients with respect to the nearest neighbors of the starting pixels whose correlation is above the first correlation threshold are examined and a path representing the smallest phase difference is chosen as the first step in the creation of a path. The process is continued and, with each step, a maximum of three new neighbors is added to a list of possible path extensions. The list is sorted by step size, and the smallest step size is selected as the next path extension. This continues until all pixels that can be reached by paths containing only pixels with correlation above the first correlation threshold are on a path. In the same way, the paths are then extended to include all pixels with correlation above the next lower correlation threshold.

Abstract: A method provides for contactless measurement of the range between a transceiver unit for microwaves in the frequency band from 1 to 100 GHz and an object to be investigated using a pulse principle. The microwaves are focused onto the surface by an antenna to detect the contour of the object. In particular, the surface of a bolt produced using a spray compacting method can be detected.

Abstract: Compensating for motion of the host vehicle in a synthetic aperture radar system includes collecting inertial data with an inertial navigation system during an imaging period in which a synthetic aperture radar pulse is directed to a target. During the imaging period global positioning system corrections to the inertial data are collected. A smooth representation of the global positioning system corrections is formed and then the smooth representation of the global positioning system corrections is applied to the inertial data after completion of the imaging period.

Abstract: A synthetic aperture radar apparatus which analyzes Doppler frequency displacements arising from a range direction motion component of a target and motion components of a flying body to produce a motion target image wherein only azimuth direction motion components of the target are converted into Doppler components. An SAR apparatus wherein SAR reproduction processing is performed based on target information obtained from a reflected wave received from a target and flying information of a flying body includes a recording and reproduction unit for recording the target information and reproducing the data in a designated range, and a moving target processor for analyzing Doppler frequency displacements arising from a range direction motion component of the target and motion components of the flying body from the reproduced data and producing a moving target image wherein only azimuth direction motion components of the target are converted into Doppler components.

Abstract: A parallel processing approach for use in multiple hypothesis tracking applications that provides partitioning and load balancing to achieve greater processing efficiency. The present invention comprises a plurality of processors that are each coupled to a shared memory, and which communicate to a central database stored in the shared memory. The central database is organized as a collection of radar tracks. Radar data is supplied to the processors as an input data stream organized in terms of radar tracks.

Abstract: A method of identifying and detecting remote objects by transmitting wave energy and receiving wave energy reflected from the object. Separate signal parameters pertaining to the wave energy received are processed forming a measured signature of the object. The measured signature is compared with a number of prestored signatures having the same signal parameters relating to known objects of interest. A recording is made of which prestored signatures correspond to the measured signature within predetermined tolerances. Subsequent transmission and reception of wave energy is used for updating the separate parameters and the measured signature. The updated measured signature is compared with the recorded prestored signatures for updated recording of a smaller number of prestored signatures corresponding to the updated measured signature within the predetermined tolerances.

Abstract: A radiometer (100) uses the fringe pattern of an interferometer (110) to scan a scene to produce a time record from which a high-resolution radio frequency, or other radiation, distribution of the scene can be reconstructed. A matched filter (120), or other means, transforms the time record according to a function of a signature of the determinable scanning motion relative to the fringe pattern.For many applications, the modulation transfer function (123) of an included matched filter is the complex conjugate of the Fourier transform of the signature that would be produced by a constant point emitter scanned by the lobes of the interferometer fringe pattern.Two-dimensional reconstructions may be provided for by multiple scans at different orientations. Alternatively, frequency scanning or another scanning technique can provide resolution orthogonal to the fringe pattern scanning motion.

Abstract: A method and apparatus for real time SAR recording and processing includes a first movable recording medium in the form of a rotatable disc having reusable and erasable photosensitive materials thereon to record SAR returns in the form of radial traces. The first recording medium is rotated to move successively through a write zone where the SAR returns are recorded and a read zone where the recorded SAR returns are optically processed to produce a SAR image. The SAR image is recorded on a second rotatable recording medium having reusable and erasable photosensitive materials. The second rotatable recording medium moves successively through a record zone where the SAR image is recorded in a transfer zone where the SAR image is interfaced with a further optical processing system such as an optical correlator.

Abstract: A tracking receiver is disclosed which utilizes optical processing for detecting and tracking input broadband chirp like emission signals. The tracking receiver includes a scanning local oscillator, the output signal of which is caused to be scanned in frequency. A mixer mixes the unknown input signal and the local oscillator output signal to produce an intermediate frequency (IF), frequency difference signal. The IF signal is analyzed in an optical spectrum analyzer which includes an acoustooptical modulator for modulating a beam of radiation, as a laser beam, with the intermediate frequency signal, and optical means, as a lens, for producing a spatial frequency distribution of the intermediate frequency spectrum in a Fourier plane. A photodetector array is provided in the Fourier plane for detecting the spatial spectrum.

Abstract: With a traffic monitoring device for photographic recording of vehicles exceeding a predetermined speed, the speed of the approaching traffic is measured substantially against the travelling direction. The vehicles (12) are photographed frontally when they exceed the predetermined speed. Two speed measurements are effected: A first measuring value is obtained in a relatively short part of the available measuring section (22) on the entrance side and serves to release a camera (18). A second measuring value evaluates all speed measuring values occuring in the measuring section (22), in which the vehicle (12) is detected by the radar beam (20). This second measuring value is recorded.

Abstract: A null command generator test apparatus capable of operating in either the open or closed loop configuration for testing the Sarcalm system. When operating in an open loop configuration the null command generator test apparatus utilizes the normalized voltage output of the null command generator as the estimator for the beam pointing error. When operating in the closed loop configuration, the test apparatus utilizes either the voltage output of the null command generator or the angle difference between the line of sight to the target and the null direction of the antenna servo simulator to estimate the dynamic pointing errors.

Abstract: A recording and reproducing system for radar signal information includes a pulse stretcher that detects master trigger pulses and, upon each occurrence, provides a stretched pulse having extended duration consistent with a selected recording bandwidth; a detector to detect the stretched pulses and to provide a binary information signals; an echo pulse processor to sample and quantize radar echo pulses to at least one bit level. The quantized echo pulses are recorded on multiple channels and the binary information signals are recorded on a single channel of selected bandwidth.

Abstract: Two alternative methods are disclosed for digital reduction of synthetic aperture multipolarized radar data using scattering matrices, or using Stokes matrices, of four consecutive along-track pixels to produce "averaged" data for generating a synthetic polarization image.

Abstract: A method and apparatus are described for use during testing of air-borne ground surveillance radar installations to provide positive identification of targets and other ground features in the recorded or displayed radar returns.