797 results about "Radar antennas" patented technology

An airborne radar system is disclosed. The airborne radar system comprises a radar antenna, radar circuitry coupled to the radar antenna, and a runway database comprising runway location information. The airborne radar system also comprises a processing device retrieving from the runway database, runway location information for a runway being approached by an aircraft, based on the location of the aircraft, and directing a radar beam defined by a polygon which represents the runway and which is derived from the runway information, the processing device determining whether there are any obstacles on the runway.

A method and system for processing radar data obtained from a platform which is subjected to non-uniform movement, the distance the platform travels during the formation of an image comprising an aperture; the system comprising software programming for performing a subroutine for building up an average pulse representing a single point on the aperture; the subroutine comprising the steps of inputting radar data from a radar antenna; passing the radar signal through low noise amplifier to reduce impact of electronic noise from the radar system; down converting the signal with a mixer to obtain a lower frequency; filtering out harmonics from the higher frequency range; sampling the radar data using an analog to digital converter at least at Nyquist down range frequency; based upon the IF of the radar; determining a scene center (center of SAR imagery) for the purpose of motion compensation; performing a two stage averaging scheme of the received signals with a variable window function; determining a window function based upon the velocity and acceleration of the platform and scene center; the window function comprising a first stage window; coherently averaging N pulses together to create an average pulse; performing an inverse Fourier transform; compensating to the scene center by multiplying by a complex exponential based upon both the GPS and inertial navigational system; summing the average pulses using low pass filter; the software programming operating to repeat the step of building up an average pulse a first predetermined number of times for a time period that is less than the Nyquist sample time interval; the software programming operating to repeat the step of building an average pulse for a predetermined number of times to generate a second predetermined number of average pulses; the software programming operating to perform a two dimensional inverse Fourier transform to obtain SAR image; outputting the SAR image on a display screen; and a display for displaying the outputted SAR image.

The invention provides a method for acquiring and imaging data of compressive sensing synthetic aperture radar. The method comprises the following steps of: 1, selecting an observation scene; 2, emitting a Chirp signal by a radar antenna; 3, receiving a distance direction signal of the synthetic aperture radar; 4, constructing a compressive sensing restoring matrix; 5, correcting distance compression and distance migration; 6, constructing an orientation direction filter matrix; and 7, compressing towards the orientation direction. By the method for acquiring and imaging the data, aiming at realizing great reduction of radar stored and transmitted data quantity in the special observation scene and synchronously realizing restoring of a distance direction pulse compression signal and correction of the distance migration, the problem that interpolation calculation cannot be performed on a compressive sensing restoring signal is solved.

The invention discloses a radar foresight super-resolution imaging method which specifically includes: distance toward pulse compression, distance walking corrosion, distance toward inverse fast fourier transform (IFFT), determination of iterations and azimuth deconvolution. The radar foresight super-resolution imaging method performs azimuth modeling on echo scanned by a radar antenna in foresight mode to enable the echo to be in convolution, and estimates front ground feature distribution information in a deconvolution method; and additionally, based on noise statistical property, optimum iterations can be determined according to iteration deconvolution, so that radar can obtain better foresight super-resolution imaging performance. Compared with the background technology, the radar foresight super-resolution imaging method overcomes the restrains on scene of a single-pulse imaging technology and limitation on platform dimension of an array imaging method, further solves the problems of complex synchronization, motion compensation and the like of double-foundation synthetic aperture radar (SAR) and can effectively obtain ground feature distribution information of the area dead ahead the platform.

The invention relates to a transmit-receive split planar array phased-array radar antenna array and a beam former. The method comprises designing and arranging antenna receiving arrays and transmitting arrays, connecting radar receiving assemblies with transmitting assemblies, designing beam formers of receiving large arrays and transmitting large arrays, and finally, forming synthesis scanning wave beams by use of the receiving large arrays and the transmitting large arrays, such that the problem of grid lobes generated during antenna scanning is overcome. The method is applied to low-cost design of an active phased-array radar, and is especially suitable for design of a multifunctional active phased-array radar which combines a mechanical scanning mode with an electrical scanning mode.

The invention discloses a method for measuring a target azimuth by single-beam mechanical scanning radar, which relates to the technical field of radar and communication and solves the problems of low angle measurement precision and large operation amount of the conventional single-beam mechanical scanning radar. The method comprises the following steps of: acquiring echo signals by using the single-beam mechanical scanning radar, then performing phase coherence accumulation on the acquired echo signals to acquire a higher signal detection signal-to-noise ratio, taking an azimuth interval of any two echo pulses of a main lobe width of a radar antenna as two beams required for measuring an angle by the single-pulse technology after target information is detected, then calculating two-dimensional images, sum signal intensity and difference signal intensity of a target on two azimuths, and further calculating a sum-to-difference ratio k so as to acquire a target error deflection angle delta theta, wherein the target azimuth theta T is equal to theta i + theta k + delta theta. The method is suitable for radar angle measurement.

The invention discloses an ocean current field inversion satellite-borne SAR system based on angle diversity, and a method thereof. The satellite-borne SAR system comprises two radar antennas which are arranged in the flying direction of a satellite, wherein the two radar antennas respectively generate two radar wave beams; and the two wave beams have different squint angles and can irradiate the same area on the ocean surface in different time. The method comprises: utilizing the satellite-borne SAR system and taking a doppler center frequency as the observation variable to perform inversion on an ocean current field; and obtaining a complete velocity vector of an ocean current, that is, the ocean current information obtained through inversion not only includes the radial velocity information of the ocean current but also includes the azimuth velocity information. Compared with a traditional ocean surface current field inversion means, such as field observation and shore-base radar observation, the ocean current field satellite-borne SAR system based on angle diversity can realize inversion of a worldwide ocean current field, can comprehensively know about temporal and spatial variation of the ocean current, and can work all day long and all weather without limitation of meteorological conditions.

The invention relates to a phased array radar transmitting channel far-field calibration method and system. Two antennas are erected in a far field, the polarization manners of the two antennas are vertical to each other, an auxiliary antenna is mounted beside a radar array surface, the polarization manner of the auxiliary antenna is vertical to the radar array surface, and the auxiliary antenna is used for receiving signals transmitted by the second antenna in the far field. A radar signal processing machine performs phase testing on a signal transmitted by an auxiliary receiving channel, the phase of the signal transmitted by the auxiliary receiving channel is regarded as a transmitting reference phase, the phase of each channel transmitting signal of the radar array surface is compared with the transmitting reference phase, the required phase correction is acquired by subtraction, the phase shifter of a transmitting component is controlled to perform shifting according to the obtained phase correction, and transmitting channel far-field calibration is achieved. Compared with traditional methods, the calibration method and system has the advantages that signal measuring equipment such as a spectrometer and an oscilloscope which are erected at a far end is omitted, and reference clock transmitting to the far end is omitted.

The invention discloses a three-dimensional fine imaging system based on a drilling geological radar technology. The system comprises devices, such as a radar transmitting antenna, wherein the radar transmitting antenna is transmitted into a bore through a radar antenna transmitting device; a radar receiving antenna moves along a measuring line on a tunnel work area surface through a radar antenna driving device; the radar transmitting antenna and the radar receiving antenna are connected with a radar host machine; the radar host machine is respectively connected with a storage battery and a computer; the radar antenna transmitting device and the radar antenna driving device are connected with a control host machine; and the control host machine is connected with the storage battery through a power wire and controls the antenna to transmit and the driving device. The invention also provides a stereo three-dimensional observing method. Three-dimensional detection on surrounding media of the bore is realized by matching the method with a 'transmitting, receiving, circulating and detecting' way based on coverage observation for multiple times, and by a speed imaging method based on constrained reversion and a three-dimensional interpolation method, and the three-dimensional fine detection on the geological status in front of the tunnel work area surface is realized.

The invention belongs to the technical field of robots and discloses a 6-PSS parallel mechanism and a position forward and inverse solution method. A circular rail is arranged and provided with six sliding modules which move actively and precisely along the rail. The sliding modules are connected with the lower ends of connecting rods of a fixed length through spherical hinges correspondingly. Theupper ends of the connecting rods are connected with a motion platform through spherical hinges correspondingly. According to the 6-PSS parallel mechanism and the position forward and inverse solution method, six-degree-of-freedom motion of the motion platform can be achieved, the mechanism is remarkably characterized in that the motion platform can rotate at any angle around the vertical axis, the motion flexibility of the mechanism is improved, and the posture adjustment work space is expanded; and the mechanism can be applied to multiple occasions including light radar antenna pedestals, radiotelescope feed source supporting platforms, motion simulators and the like. The mechanism and method provided by the invention are easy to operate, and the problem that a Stewart platform traditional six-degree-of-freedom parallel robot is limited in work space is effectively relieved; and the motion platform moves by driving the six parallel sliding modules, and the motion speed of the motionplatform is increased.

A RADAR system including a set of RADAR apparatuses is disclosed. Each apparatus includes a processor, a pulse unit in signal communication with the processor, a waveform signal generator in signal communication with the pulse unit, and a set of radar antennas in signal communication with the waveform signal generator. The waveform signal generator is capable of generating a waveform signal in response to pulses provided by the pulse unit. The set of antennas is capable of transmitting a burst of microwave energy in response to each waveform signal and to receive a plurality of reflected bursts associated with the transmitted bursts. An acquisition unit is configured to develop and amplify a finite window integral associated with each reflected burst, the acquisition unit in signal communication with the set of antennas and a pre-processor configured to digitize and store information relating to each finite window integral for subsequent processing.

The invention relates to an ultra-low signal-to-noise ratio medium and high orbit satellite target ISAR imaging method, and mainly relates to the technical field of inverse synthetic aperture radar imaging. The method provided by the invention comprises the steps that the slant range course between a ground radar and a target satellite is calculated by using a target satellite orbit and the phasecenter position of a radar antenna, and pulse compression is carried out on original echo data received by the radar; according to the slant range course and radar imaging geometric parameters, the curvature walk of a target envelope is corrected; the delay phase of an ionized layer is compensated along azimuth, and a linear model is used to correct an envelope alignment error caused by a radar geometric parameter measurement error and a satellite orbit measurement error; the translation phase of the target is compensated, and fast Fourier transform (FFT) along azimuth is carried out to acquire an initial ISAR image; and finally, the quadratic translation phase error of the target is estimated and compensated according to the initial ISAR image, so as to acquire a final medium and high orbit satellite target ISAR image.

A motion compensation method and system is included in a radar antenna system mounted on a moving platform which is subject to pitch, yaw and roll. The radar antenna system includes a main array antenna, and an auxiliary antenna. The auxiliary channel associated with the auxiliary antenna utilizes roll, pitch and yaw angle motion compensations as its auxiliary antenna always steers a horizontal fan shape beam at the horizon to blank any surface (land or sea) based EM interferences. Such motion compensations are provided by a ship motion compensator component and process included within the antenna system. The ship motion compensator component in response to platform motion signals indicative of changes in platform motion angles generates new sets of values using an initial set of weighting coefficient values as a function of such angle motion changes. This produces changes in both amplitude and phase weighting coefficient values which results in both the quadrant phase rotation and the element weighting rotation. The process steers and spreads out the received auxiliary antenna pattern making sidelobe coverage broad enough to compensate for such changes in platform motion.

The invention discloses a method and a device for detecting geological flaws at bottom of foundation pile holes through geological radar. The device comprises a geological radar instrument (1) and a radar antenna (2) with frequency of 270Mhz, wherein the radar antenna (2) is connected with the geological radar instrument (1) by a radar antenna connecting cable (3); and an antenna lifting rope (4) and a pulley (8) are arranged and used for deploying and retracing the radar antenna (2). According to the method and the device disclosed by the invention, the advanced geological-radar based karst cave detecting technology is adopted, and the structural features of foundation pile holes are fully utilized, therefore, the karst caves at the bottom of the pile holes and the karst caves within 10 meters from piles can be detected; the method and the device are large in detection scope, high in field working efficiency, and clear in karst carve detection; by adopting the method and the device, the works of mechanically drilling holes or artificially drilling holes can be avoided, and the existence, the depth and the scope of the karst caves at the bottom of the piles and the karst carves within the scope of the pile hole embedment depth in rock can be universally detected; and a new efficient and quick method is provided for inspecting and accepting the engineering foundation pile holes.

The invention belongs to the technical field of vehicle-borne radars, and particularly relates to a high-mobility large-scale radar vehicle. The radar vehicle comprises an assembling platform and an electronic equipment cabin, wherein leveling supporting legs are arranged on the lower plate surface of the assembling platform; a fixed antenna and a folded antenna are arranged at the electronic equipment cabin; the folded antenna is driven by a hydraulic driving assembly, so that two position conditions of withdrawing and unfolding are generated along a vertical surface; when the folded antenna is under a withdrawing condition, the antenna plate surface of the folded antenna is vertically arranged, when the folded antenna is under an unfolding condition, the antenna plate surface of the folded antenna is horizontally arranged, and the antenna plate surface of the folded antenna and the antenna plate surface of the fixed antenna are in the same plane; and the radar vehicle also comprises a servo control system and an electric generating system. According to the high-mobility large-scale radar vehicle disclosed by the invention, the situation that the width and the height are not exceeded during the transporting of radar antennas can be guaranteed, functions of quick erecting and quick removing of an antenna array surface can also be realized, and finally, the high mobility of the ground vehicle-borne radar is guaranteed.

The invention discloses a method for calibrating an antenna angle of millimeter-wave weather radar. The method comprises specific steps as follows: step one, a millimeter-wave weather radar antenna angle calibration platform is put up and comprises an industrial control computer (1), a theoretical sun position determination module (2), a sun position measuring module (3), an antenna angle processing module (4), an antenna controller (5) and a signal processor (6); step two, the theoretical sun position determination module (2) determines the theoretical sun position; step three, the sun position measuring module (3) controls the measuring sequence of the sun positions and acquires time, antenna angle and atmospheric noise data; and step four, the antenna angle processing module (4) processes the acquired data and determines and calibrates the error of the antenna angle. Accordingly, the calibration of the antenna angle of the millimeter-wave weather radar is realized. By means of the method, the calibration of the antenna angle of the millimeter-wave weather radar can be conveniently and rapidly finished, the calibration can be performed at any time as required, and the accuracy and the high quality of observation data are guaranteed.

The invention discloses a three-dimensional correlated imaging method based on phased array radar and relates to the field of radar imaging. The three-dimensional correlated imaging method based on the phased array radar comprises the steps that firstly, the antenna array surface of the phased array radar is divided, a linear frequency modulation signal is sent by a phased array radar transmitter, echo signals of target scattering points are received, and the phase shifting values of the target scattering points are set; secondly, base frequency echo signals obtained after distance pulse pressing are divided according to the distance unit; thirdly, an objective function for the scattering coefficient vectors of the target scattering points is constructed, and the objective function is solved under the sparse constraint condition, so that the estimated value of the scattering coefficient vector of the target scattering point in the u distance unit is obtained; fourthly, a two-dimensional image is formed through the estimated value of the scattering coefficient vector of the target scattering point in the u distance unit, and then a three-dimensional image is obtained by ranking the two-dimensional images of all the distance units in the sequence the same as that of the distance units. By the adoption of the three-dimensional correlated imaging method based on the phased array radar, high-resolution three-dimensional imaging of a target is achieved.

A method for determining beamformer scattering parameters for a plurality of phased array radar antenna subarrays that each include a radiating (e.g., dipole) component and a beamformer component provides for obtaining for the plurality of phased array radar antenna subarrays a plurality of electromagnetic measurements at a plurality of ports. Analogous electromagnetic measurements are obtained for a reference subarray including a radiating component but absent a beamformer component. The plurality of phased array radar antenna subarray electromagnetic measurements and the reference subarray electromagnetic measurements provide a plurality of beamformer scattering parameter values for the plurality of phased array radar antenna subarrays that may be used in modeling and calibrating a phased array radar apparatus that may be assembled from the plurality of phased array radar antenna subarrays.

The invention belongs to the field of radar stealth, and discloses a wave absorbing/transmitting device of a composite window absorber. The wave absorbing/transmitting device sequentially comprises afirst wave-absorbing layer (1), a first dielectric isolation layer (3), a second wave-absorbing layer (4), a second dielectric isolation layer (7), a third wave-transmitting layer (8), a third dielectric isolation layer (11) and a fourth wave-transmitting layer (12) from top to bottom, wherein the first wave-absorbing layer (1) is provided with a cross-shaped pattern (2) array, the second wave-absorbing layer (4) is provided with a framed cross-shaped pattern array, and the third wave-transmitting layer (8) and the fourth wave-transmitting layer (12) are respectively provided with framed square pattern arrays. According to the invention, by improving the structure of each component of the device, the arrangement mode of the components and the like to construct the double wave absorbing layers, the problem that the existing window wave absorbing body cannot give consideration to out-of-band bilateral double-frequency-band broadband wave absorption and in-band broadband wave transmissionat the same time is effectively solved, and thus the radar antenna system is ensured to have better out-of-band RCS reduction.

The invention discloses a cylindrical-array-based centralized MIMO (multiple input multiple output) radar waveform optimization method, which mainly comprises the following steps: determining a cylindrical-array-based centralized MIMO radar, the cylindrical-array-based centralized MIMO radar integrating sending and receiving and comprising N circles of array elements and each circle of array elements comprising Nt array elements, and obtaining phase difference column vectors of the N circles of array elements relative to the antenna phase center of the cylindrical-array-based centralized MIMO radar and electric field intensity column vectors of the N circles of array elements respectively; further calculating guide vectors of the N circles of array elements; calculating a receiving beamforming weight of the centralized MIMO radar, and further calculating an optimal receiving beamforming weight of the centralized MIMO radar; recording expected sending directional diagrams, then arranging the expected sending directional diagrams to obtain column vectors of the expected sending directional diagrams according to an arrangement sequence of the phase difference column vectors, calculating a designing criterion of a waveform matrix S of the N circles of array elements of the centralized MIMO radar, and further calculating a final waveform matrix of the centralized MIMO radar.

A system for bistatic radar target detection employs an unmanned aerial vehicle (UAV) having a ramjet providing supersonic cruise of the UAV. Deployable antenna arms support a passive radar receiver for bistatic reception of reflected radar pulses. The UAV operates with a UAV flight profile in airspace beyond a radar range limit. The deployable antenna arms have a first retracted position for supersonic cruise and are adapted for deployment to a second extended position acting as an airbrake and providing boresight alignment of the radar receiver. A mothership aircraft has a radar transmitter for transmitting radar pulses and operates with an aircraft flight profile outside the radar range limit. A communications data link operably interconnects the UAV and the tactical mothership aircraft, transmitting data produced by the bistatic reception of reflected radar pulses in the UAV radar antenna to the mothership aircraft.