Abstract: A forward-looking radar system adapted to detect and identify buried or near surface objects from a moving ground vehicle has been developed. The system incorporates a radar detection system and in one embodiment is mounted on a ground vehicle. The system is adapted to differentiate common roadway clutter from objects of interest.

Abstract: An apparatus a transmitter section, a receiver section, and a processing module. The transmitter section transmits a plurality of high carrier frequency beamformed signals in a loop manner until a desired number of signals has been transmitted. The receiver section receives the plurality of high carrier frequency beamformed signals and determines reception properties of the plurality of high carrier frequency beamformed signals. The processing module determines at least one of: reflection, absorption, refraction, and pass through based on the reception properties. The processing module then distinguishes an animate entity from an inanimate entity based on the at least one of the reflection, absorption, refraction, and pass through. The processing module then determines position of the animate entity within a given physical area.

Abstract: Methods and apparatus for processing data from a low beam channel, a high beam channel and a weather channel to perform an altitude estimation based upon a target amplitude ratio between the low beam channel and the high beam channel and target range, and for performing target detection based upon data from the weather channel. In one embodiment, migrating birds can be more accurately detected and classified than with conventional systems.

Abstract: A wireless sensor apparatus includes first and second polarization antennas whose polarization surfaces of radiation waves are mutually orthogonal, a first mixer circuit connected to the first polarization antenna and configured to input a first reception signal received by the first polarization antenna, a second mixer circuit connected to the second polarization antenna and configured to input a second reception signal received by the second polarization antenna, a signal generation circuit configured to generate pulse signals fed to the first and second polarization antennas and also supplied to the first and second mixer circuits, and a differential amplification circuit configured to perform a differential amplification on a mixed output obtained by mixing the first reception signal and the pulse signal by the first mixer circuit and a mixed output obtained by mixing the second reception signal and the pulse signal by the second mixer circuit.

Abstract: A polarimetric radar with V and H polarized array antenna elements which transmit a V component modulated by a V code and the H component modulated by an H code orthogonal thereto. Unwanted polarization errors occur at off-boresight angles, which tend to obscure the polarization characteristics of the target. Radar returns are processed to form four independent channels by convolving the signals received by the V and H antennas with the mutually orthogonal V and H codes. This overcomes the polarization obscuration and allows determination of the polarimetric ratio of the target with high accuracy.

Abstract: A variable ratio power divider (VRPD) used for adjusting a calibration signal for a dual polarization radar system has been developed. The VRPD includes an input line that receives a calibration signal and splits the calibration signal into two separate test signals that have a 0° phase shift between them. The VRPD also includes a horizontal polarization output port for a horizontal calibration signal and a vertical polarization output port for a vertical calibration signal. A waveguide switch receives one of the test signals. If the waveguide switch is operating in a first position, it passes the test signal through a variable 0°-180° phase shifter. This evenly divides the power of the test signals between the horizontal and vertical output ports. If the waveguide switch is operating in a second position, it causes the test signal to bypass the phase shifter so that the entire power of the both test signals is directed entirely to either the horizontal phase output port or the vertical phase output port.

Abstract: According to one embodiment, a dual polarization radar apparatus includes a received power calculation unit configured to calculate a horizontal polarization received power and a vertical polarization received power, the horizontal polarization received power indicating a power value of a horizontal polarization received signal reflected from an observation target, the vertical polarization received power indicating a power value of a vertical polarization received signal reflected from the observation target, a power ratio calculation unit configured to calculate a power ratio between the horizontal polarization received power and the vertical polarization received power, and an interference judgment unit configured to judge that an interference signal is mixed to the horizontal polarization received signal or the vertical polarization received signal when the power ratio is greater than a predetermined threshold value.

Abstract: A method and a device for the spatially resolved detection and reconstruction of objects using microwaves is described, in which at least one object to be detected is subjected to microwaves that are generated by a plurality of microwave antennas and microwave fractions reflected by the object are detected and converted into microwave signals that can be analyzed, based on which an analysis for the spatially resolved object detection is carried out.

Abstract: Systems and methods are provided for adaptively estimating the specific differential phase (Kdp) from dual-polarization radar data in the complex domain. Some embodiments adapt for wrapped differential propagation phases by estimating the specific differential phase in the complex domain. Some embodiments adapt for measurement fluctuations and/or spatial scale in making such estimations. Some embodiments also provide for determining the presence of storms cells using the dispersion of the differential propagation phase shift over a subset of bins.

Abstract: A detection system comprises a transmitter unit, a receiver, and a processor. The transmitter unit is capable of transmitting a first collimated beam having a first frequency and a second collimated beam having a second frequency into a ground, wherein the first collimated beam and the second collimated beam overlap in the ground. The receiver is capable of monitoring for a response radio frequency signal having a frequency equal to a difference between the first frequency and the second frequency. The response radio frequency signal is generated by an object having non-linear conductive characteristics in response to receiving the first collimated beam and the second collimated beam. The processor is capable of controlling an operation of the transmitter unit and the receiver. The processor is connected to the transmitter unit and the receiver. The object is detected when the response radio frequency signal is detected by the receiver.

Abstract: The automotive radar includes a printed circuit board having a top surface and a bottom surface, and a processor mounted on the bottom surface of the printed circuit board. The automotive radar also includes a second liquid crystal polymer layer formed on the top surface of the printed circuit board, a second microstrip array printed on the second liquid crystal polymer layer, the second microstrip array having a patch, a first liquid crystal polymer layer formed on the second liquid crystal polymer layer, a first microstrip array printed on the first liquid crystal polymer layer, the first microstrip array having a perforated patch, and a transmit/receive module connected to a bottom surface of the second liquid crystal polymer layer and configured to transmit a first frequency signal to the first microstrip array and a second frequency signal to the second microstrip array.

Abstract: To provide a synthetic aperture radar for achieving a compact polarimetric SAR easily by using a general-purpose phased array antenna for vertical and horizontal polarizations. An antenna section is a phased array antenna for vertical and horizontal polarizations capable of switching to the vertical or horizontal polarizations in transmission at every transmission/reception module, and receiving two of the horizontal and vertical polarizations simultaneously. The control system divides electrically the phased array antenna in the elevation direction in transmission to set one of them for horizontal polarization transmission and the other for vertical polarization transmission, and sets the antenna for dual polarization simultaneous reception to receive the horizontal and vertical polarizations.

Abstract: A radar system comprises a first transmit/receive module for a first frequency band and a first polarization, a second transmit/receive module for the first frequency band and a second polarization orthogonal to the first polarization, a third transmit/receive module for a second frequency band and the first polarization, a fourth transmit/receive module for the second frequency band and the second polarization orthogonal to the first polarization, a first plurality of splitter/combiners to receive outputs from the first and second transmit/receive modules, a second plurality of splitter/combiners to receive outputs from the third and fourth transmit/receive modules, a plurality of lens phase shifter pairs to receive outputs from the first plurality of splitter/combiners, a plurality of diplexers to receive signals from the plurality of lens phase shifter pairs and from the second plurality of splitter/combiners, and, a radiator assembly including a series of radiator elements coupled to the plurality of dipl

Abstract: The system and method for standoff detection of human carried explosives (HCE) automatically detects HCE (112) up to a range of (200) meters and within seconds alerts an operator to HCE (112) threats. The system (100) has radar only, or both radar and video sensors, a multi-sensor processor (102), an operator console (120), handheld displays (122), and a wideband wireless communications link. The processor (102) receives radar and video feeds and automatically tracks and detects all humans (110) in the field of view. Track data continuously cues the narrow beam radar (118) to a subject of interest (110), (112) the radar (106), (108) repeatedly interrogating cued objects (110), (112), producing a multi-polarity radar range profile for each interrogation event. Range profiles and associated features are automatically fused over time until sufficient evidence is accrued to support a threat/non-threat declaration hypothesis.

Abstract: A system and method for filtering clutter is contemplated that in one aspect performs clutter-filtering on complex-voltages. In one aspect, spectral coefficients identified from a series of spectral coefficients as having been affected by clutter are replaced by a refilling procedure to maintain the statistical properties of the spectral coefficients that are unaffected by clutter. Dual-polarization radar variables that have phase dependence can be subsequently generated from the modified spectral data.

Abstract: A simultaneous dual polarization radar system is disclosed repositioning critical processing components below the elevation rotary coupler to avoid radar emission pulse train corruption due to waveguide phase error introductions and to fully capitalize on the simultaneous transmission of polarized signals. A fiber optic rotational coupler is introduced to allow an improved alternate data path for data transmission from the receivers to the signal processors and to allow for transmitting reflected signal returns from the receiver subsystem located above the elevation rotary coupler to the radar system processor located below the elevation rotary coupler.

Abstract: In accordance with yet another aspect of the present invention, an active imaging system is provided for imaging a target of interest. An imaging assembly includes a light source and an optical assembly comprising a plurality of passive optical components. The optical assembly divides received light into a first beam, having a first polarization and a second beam, having a second, orthogonal polarization, directs the first and second beam along respective first and second optical paths within the optical assembly, and recombines the first and second beams into a combined beam. A sensor detects the combined beam.

Abstract: A synthetic aperture radar hybrid-polarity method and architecture comprising transmitting circular polarization (by driving the orthogonal linear feeds simultaneously by two identical waveforms, 90° out of phase), and receiving horizontal (H) and vertical (V) linear polarizations, coherently. Once calibrated, the H and V single-look complex amplitude data are sufficient to form all four Stokes parameters, which fully characterize the observed backscattered field.

Abstract: The invention is a low-cost, compact radar for adaptively forming beams and independently steering the beams to improve the noise and sensitivity of the radar. The radar includes a printed circuit board, a low-cost multi-layer organic substrate, and a three dimensional (3D) radio frequency (RF) front end that is flood mounted on the substrate.

Abstract: The reflectarray comprises an array of patch elements (10-13). Each patch element has a cut ring shape formed of a conductive ring with at least one crossing gap. The outer diameter and inner diameter and crossing gap are adjusted so that a phase shift ? defined by the following relations is different from zero: ?(Eox)=?(Eix)+? (1) ?(Eoy)=?(Eiy)+?+? (2) where: ??(Eox) and ?(Eoy) are the phases of the orthogonal components and of the reflected wave, respectively, ??(Eix) and ?(Eiy) are the phases of orthogonal components and of the incident wave, respectively, ?? is a phase angle.

Abstract: A device and method for measuring phase and power shifts in a simultaneous dual polarization radar system comprises an access port, a quadrature mixer, and a power detector. The access port is configured to couple to the simultaneous dual polarization radar system near the antenna of the simultaneous dual polarization radar system. The quadrature mixer is configured to mix a first signal from a first polarization and a second signal from a second polarization. The first signal and the second signal are sampled through the access port. The first power detector is configured to measure the power level of the first signal.

Abstract: A radar system and method that employs polarization-time diversity in transmitting signals and concurrently processing received reflections from both polarization modes provides information about the scattering matrix of a target without loss of information. Illustratively, the transmitted signals from Golay pairs, and the processing method employs a complex-conjugate time reversal operand. The received reflected signals are processed for a particular distance in mind to develop a scattering matrix of the medium at that distance. By comparing the scattering matrix to known scattering matrices an identification of the target from where the transmitted signals were reflected is obtained.

Abstract: A radar system and method that employs polarization-time diversity in transmitting signals and concurrently processing received reflections from both polarization modes provides information about the scattering matrix of a target without loss of information. Illustratively, the transmitted signals from Golay pairs, and the processing method employs a complex-conjugate time reversal operand. The received reflected signals are processed for a particular distance in mind to develop a scattering matrix of the medium at that distance. By comparing the scattering matrix to known scattering matrices an identification of the target from where the transmitted signals were reflected is obtained.

Abstract: A mechanism that enables a gateway to dynamically determine which of two transmission signal polarizations is best received by a wireless communication device having a nominally linear antenna. A first pilot and second pilot signals, having different polarizations and orthogonally encoded, are transmitted to the communication device. The communication device determines the relative or absolute signal strengths of the first and second pilot signals and transmits this information to the gateway. The gateway then selects the polarization having the strongest associated signal strength to transmit content-bearing signals to the communication device. Alternatively, the communication device may also determine the phase difference between the first and second pilot signals and transmit this information to the gateway.

Abstract: A method of calibrating a dual polarization weather radar system has been developed. The method first generates a transmission pulse from the radar system. The transmission pulse is then modified to generate a test signal that simulates a desired atmospheric condition. The test signal is transmitted directly into the radar system from a test antenna and the radar system is calibrated according to the test signal.

Abstract: A system for the measurement of an angle of roll of a projectile is disclosed. The projectile has a casing with a rear end, a front end, and a side wall extending therebetween. The system includes a radar configured to transmit a polarized electromagnetic signal toward the projectile and a groove disposed on the side wall of the casing. The groove has a width, a depth, and a length, the width extending along a longitudinal axis of the projectile, the depth extending inwardly from an outer surface of the casing toward the longitudinal axis, and the length extending along the outside of the casing. The radar is further configured to receive a return signal from the projectile, wherein the return signal from the groove is modulated as a function of the angle of roll of the projectile. Amplitude or phase modulation of the return signal from the groove can be used to uniquely determine the roll angle of the projectile.

Abstract: Methods for suppressing cross-track clutter in a sounding radar utilize polarimetric selectivity in two ways: (1) transmitting full-beam circular polarization and separating the desired signal of interest from the clutter based on the signal and clutter having different polarizations, and (2) transmitting and receiving circular polarization at the radar's nadir and elliptical polarization at the radar's off-nadir regions and filtering out the elliptical polarization.

Abstract: A method for detection of an object, the method including irradiating a target with two electromagnetic wave energy beams, a first beam at a first frequency and a second beam at a second frequency, the first frequency being lower than the second frequency, both beams being polarized in a first direction, and determining a presence of an object by analyzing reflections of the first and second beams, wherein if there is a dominant reflection polarization in the first direction for both the first and second frequencies, then the target is considered not to have the object, and if there is a dominant reflection polarization in the first direction for only one of the first and second frequencies and a depolarized reflection at the other of the first and second frequencies, then the target is considered to have the object.

Abstract: The present invention can be summarized by use of a diffraction limited SAR giving large integration angle and a short depth of field which gives that energy from underground targets is focused independently at different depths to enable 3d imaging. The radar device according to the invention should be implemented by considering the following parameters: Choice of the appropriate illumination geometry, i.e. elevation angle ?, and the appropriate use of low frequency diffraction limited SAR processing to obtain 3D imaging, and the choice of an appropriately low radar frequency.

Abstract: A calibration system for the receiver of a dual polarization radar system has been developed. The system includes a radar transmitter that transmits signals in horizontal and vertical polarizations and a radar receiver that receives the horizontal and vertical polarization signals. The system also includes a test signal generator that generates a continuous wave test signal. A calibration circuit for the radar receiver modifies the test signal to simulate weather conditions by adjusting the attenuation and Doppler phase shift of a continuous wave test signal.

Abstract: A system for simultaneously propagating dual polarized signals in a polarimetric radar system includes a system for shifting the phase of one of the two signals. The simultaneous dual polarization weather radar transmits signals in both the horizontal and vertical orientations at the same time. Upon reception, the signals in each channel are isolated and a number of standard and polarimetric parameters characterizing atmospheric conditions are determined. The accuracy upon which these parameters can be determined depends partially upon the interference between these two channels. The system and method isolates the vertical and horizontal channels by using the phase information from the signals to minimize the interference.

Abstract: A radar level gauging system comprising a microwave unit for transmitting and receiving first microwaves having a first and second distinguishable characteristics, a microwave absorber adapted to be arranged in a bottom region of the tank and adapted to absorb electromagnetic energy of microwaves having one of the first and second characteristics, and processing circuitry adapted to determine the product level based on a relationship between transmitted and received microwaves. The system thus emits microwaves in two channels, and the absorber is arranged to absorb energy in only one of the channels. Using the absorbed channel, it is possible to obtain a measurement with very limited interference from the bottom, which thus will be accurate also for levels close to the bottom. Using the unabsorbed channel, it is possible to obtain a reference measurement of the distance to the reflecting part of the absorber, thus enabling verification of the of the system.

Abstract: A variable ratio power divider (VRPD) used for adjusting a calibration signal for a dual polarization radar system has been developed. The VRPD includes an input line that receives a calibration signal and splits the calibration signal into two separate test signals that have a 0° phase shift between them. The VRPD also includes a horizontal polarization output port for a horizontal calibration signal and a vertical polarization output port for a vertical calibration signal. A waveguide switch receives one of the test signals. If the waveguide switch is operating in an open position, it passes the test signal through a variable 0°-180° phase shifter. This evenly divides the power of the test signals between the horizontal and vertical output ports. If the waveguide switch is operating in a closed position, it causes the test signal to bypass the phase shifter so that the entire power of the both test signals is directed entirely to either the horizontal phase output port or the vertical phase output port.

Abstract: A radar system includes a transmitter stage for generating a certain transmission signal; a circularly polarized antenna for emitting the transmission signal in a form of a circularly polarized signal, and receiving a reflection signal; a polarizer for isolating the reflection signal received from the circularly polarized antenna from the transmission signal, and outputting the reflection signal to a next stage; and a receiver stage for receiving the reflection signal output from the polarizer, converting the reflection signal into a signal of a certain frequency by using as a certain mixer switching signal the leakage signal leaking from the transmitter stage, and outputting the converted reflection signal. Therefore, the high-sensitivity radar system can be built in a compact size.

Abstract: The present invention relates to a method and apparatus for simultaneous transmission of horizontal (H) and vertical (V) channels in a dual polarized weather radar. The goal of the invention is accomplished by placing the receiver, duplexer and polarizer equipment above the azimuth rotary joint but below elevation rotary joints. The elevation rotary joints and other associated signal paths are calibrated by using a low power signal on the radar's operating frequency that is fed into couplers above the elevation rotary joints.

Abstract: Methods and apparatus for early detection and identification of a threat such as individuals carrying hidden explosive materials, land mines on roads, etc. are disclosed. One method comprises illuminating a target with radiation at a first polarization, collecting first radiation reflected from the target which has the same polarization as the first polarization, illuminating a target with radiation at a second polarization, and collecting second radiation reflected from the target which has the same polarization as the second polarization. A threat determination is then made based on the difference between the energy values of the first and second collected radiations. In other embodiments, the difference between energy values is used in conjunction with an evaluation of the returned energy in comparison with returned energy from other targets in order to additionally assess whether the primary target is a threat.

Abstract: The invention relates to a system, device, and method for using radar signals to measure the distance (h) to a surface from said device, the device comprising a transmitter and a transmitting antenna for transmitting radar signals, and a receiver and a receiving antenna for receiving a radar signal. The device may also comprise a first additional reflecting object separate from the receiving antenna, which additional reflector is designed so as to introduce a first predetermined alteration in radar signals upon reflection, with the device being equipped with means to differ between received signals with and without said predetermined alteration. The first predetermined alteration introduced by the first separate reflector can be, for example, a modulation shift or a shift in the polarization of the signal. In a typical embodiment the additional reflector is located close to the radar unit creating a double transition from radar unit to the surface.

Abstract: In one embodiment of a positioning system, a transmit element is configured to transmit at least one electromagnetic pulse having a carrier signal frequency. An antenna array with a plurality of receive elements includes at least two receive elements separated by a spacing more than a half wavelength. Each of the at least two receive elements is configured to receive a return signal over a period of time. The return signal includes a return pulse from an object within a detection area of the system. The wavelength corresponds to the carrier signal frequency of the transmitted pulse. A detector is configured to process the return signal from one receive element and the other receive element so as to isolate the return pulse received at each of the at least two receive elements and thereby determine a position of the object in relation to the system.

Abstract: Method, system and computer program product for replacing a portion of a digital signal by applying a first difference correction that, after range limiting, converts the samples in the replacement portion to extremum values; then applying a second difference correction based on the difference between the extremum values and the desired replacement values. The first and second sets of correction values are thus independent of the original values in the first digital signal.

Abstract: Method and apparatus for detecting objects. In one embodiment, a person entering a secured zone is illuminated with low-power polarized radio waves. Differently polarized waves which are reflected back from the person are collected. Concealed weapons are detected by measuring various parameters of the reflected signals and then calculating various selected differences between them. These differences create patterns when plotted as a function of time. Preferably a trained neural network pattern recognition program is then used to evaluate these patterns and autonomously render a decision on the presence of a weapon. An interrupted continuous wave system may be employed. Multiple units may be used to detect various azimuthal angles and to improve accuracy.

Abstract: A system for simultaneously propagating dual polarized signals in a polarimetric radar system includes a system for coding at least one of the two signals. The simultaneous dual polarization weather radar transmits signals in both the horizontal and vertical orientations at the same time. Upon reception, the signals in each channel are decoded and a number of standard and polarimetric parameters characterizing atmospheric conditions are determined. The accuracy upon which these parameters can be determined depends partially upon the interference between these two channels. The system and method isolates the vertical and horizontal channels to minimize the interference.

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 local positioning system using co-polarized and cross-polarized radar mapping is provided. In one embodiment of the method, at least a first electromagnetic pulse having a first polarization is transmitted. A first return signal preferentially having the first polarization is received over a respective period of time. The first return signal is processed so as to isolate a first return pulse corresponding to an object within a radar detection area of the positioning system. At least a second electromagnetic pulse having the first polarization is also transmitted. A second return signal preferentially having a second polarization is received over a respective period of time. The second return signal is processed so as to isolate a second return pulse corresponding to the object. A characteristic of the object is determined in accordance with a relative signal strength of the first return pulse and the second return pulse.

Abstract: A method and apparatus are disclosed for forming an image from millimeter waves. A field of view scanned using two geometrically orthogonal, intersecting copolarized fan beams (110, 120) to receive millimeter wave radiation. The received millimeter wave radiation from said fan beams are then cross-correlated (250, 650). Also, a method and antenna (400, 610) for receiving millimeter wave radiation are disclosed. The antenna includes first and second fan beam antennas (410, 420) for receiving millimeter wave radiation and a filter (430, 440) for rotating polarization of incident millimeter wave radiation through 90 degrees received by the second fan beam antenna (410). The respective first and second beams (110, 120) intersect and are co-polarized and geometrically orthogonal to each other.

Abstract: A positioning system includes a passive, isotropic reflecting landmark at a fixed position and a device. The device transmits an electromagnetic pulse having a circular polarization and receives a return signal over a period of time. The return signal includes a reflected pulse from the reflecting landmark. The processes the return signal to isolate the reflected pulse from the return signal and to determine a range from the device to the reflecting landmark. The reflecting landmark includes a first passive reflector, a second passive reflector, and a static structure configured to statically position the second passive reflector at an angle relative to the first passive reflector. The device optionally moves in a particular direction while receiving the return signal, detects a Doppler shift in the reflected pulse portion of the return signal, and determines an angle between the particular direction and a straight line between the device and the landmark.

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 and apparatus is provided, whereby a scanning, polarization and frequency diverse radar system measures the complete polarimetric characterization of weather targets without loss of scanning speed and without an additional ambiguity in the Doppler velocity beyond that given by Nyquist's sampling theorem. In one embodiment, a linear combination of a horizontally and a vertically polarized signal are transmitted at a predetermined first frequency. Cotemporaneously or nearly cotemporaneously with the transmitted signal of the first frequency, a horizontally polarized signal is transmitted at a predetermined second frequency. Horizontal and vertical receive channels receive echoes at the predetermined first frequency to determine, but not limited to determine, the co-polar elements of the scattering matrix. Horizontal and vertical receive channels receive echoes at the predetermined second frequency to determine, but not limited to determine, the cross-polar elements of the polarization matrix.

Abstract: A polarimetric radar system transmits a signal which is nominally the desired polarization, but which may deviate therefrom. A calibration operation is performed using a symmetrical radar reflector, to determine the gains and phases of reception of two mutually orthogonal components of the received reflected signal which result in nulling of the two polarization components of the reflected signal. These gains and phases represent receive corrections which result in a simulation of perfect polarization purity on both transmission and reception. The corrections established during calibration are applied to the receive signals during normal (non-calibration) operation, to improve the effective polarization of the transmission and reception.

Abstract: The present invention concerns an apparatus for collecting ground radar data with polarization information comprising a main body exhibiting structure for moving the apparatus along the ground, a part that rotates in relation to the main body supporting a pair of antennas of transmitter and receiver type, a power source with connected control unit for controlling and governing the ground radar, a transmitter unit electrically connected to one of the pair of antennas for generating and transmitting radar pulses and a sampler unit electrically connected to the other antenna for receiving the reflected radar pulses.

Abstract: A device and method for measuring phase and power shifts in a simultaneous dual polarization radar system comprises an access port, a quadrature mixer, and a power detector. The access port is configured to couple to the simultaneous dual polarization radar system near the antenna of the simultaneous dual polarization radar system. The quadrature mixer is configured to mix a first signal from a first polarization and a second signal from a second polarization. The first signal and the second signal are sampled through the access port. The first power detector is configured to measure the power level of the first signal.