54results about How to "High azimuth resolution" patented technology

The invention relates to the technical field of radio fix radars, in particular to a millimetre wave time-division linear frequency modulation multi-object detection automobile anti-collision radar. The radar of the invention adopts full phase parameter receiving/emitting benchmark signal and time-division and time-sequence asynchronous control to receive/emit a dual-purpose quasi-light integrated medium lens antenna array, and scans the objects possible to be collided on the warning road surfaces by DSP according to lane scanning wave beam; the road situation photographing combined with the vehicle speed and GPS data MCU to control time-division n-passage modulation frequency and waveform millimetre wave linear locking phase frequency modulation; emission is carried out sequentially by R/T2, a circulator, a wave beam switch and the antenna array; echo passes through the antenna array, the wave beam switch, the circulator, the R/T1, low noise high amplifier, subharmonic mixing, middle amplifier and a time-dividing circuit and multi-object signal corresponding matching filter wave and is processed and controlled by MCU at DSP; when a plurality of road barriers are encountered, the orientation, distance and relative speed are determined by DSP restriction virtual warning; three-dimensional images are displayed by a CRT; the closer the distance of the object is, the higher the resolution is; the object which is closest to the vehicle is recognised; sound and light alarm are carried out when the distance is less than safety distance; when the distance is near to the dangerous distance, the vehicle can intelligently avoid the barrier or reduce the speed or brake; the radar of the invention can make a choice according to the control reference road situation, the vehicle speed and the GPS data, thus obviously improving the driving safety of the vehicle.

The invention relates to the technical field of radio fix, in particular to a millimetre wave time-division random code phase modulation multi-passage automobile anti-collision radar. The radar of the invention is provided with a time-division and time-sequence asynchronous control to receive/emit signal, and a receive/emit a dual-purpose quasi-light integrated medium lens antenna array, and scans the objects possible to be collided on the warning road surfaces by DSP according to lane scanning wave beam; the road situation photographing, the vehicle speed sensing and satellite positioning GPS data MCU control time-division n-passage random code millimetre wave phase modulation; emission is carried out sequentially by upper frequency conversion, R/T3, frequency doubling and power amplification, R/T2, a circulator, a wave beam switch and the antenna array; echo passes through the antenna array, the wave beam switch, the circulator, the R/T1, low noise high amplifier, subharmonic mixing, middle amplifier and extracts the multi-passage signal DSP which is processed and controlled by MCU; the driving of multi-automobile of adjacent lanes is not disturbed by each other and can be completed simultaneously; the high-performance environment electromagnetic compatible EMC is provided; when a plurality of road barriers are encountered, the orientation, distance and relative speed are determined by DSP restriction virtual warning; three-dimensional panoramic images are displayed by a CRT; the closer the distance of the object is, the higher the resolution is; the object which is closest to the vehicle is recognized; sound and light alarm are carried out when the distance is less than safety distance; when the distance is near to the dangerous distance, the vehicle can intelligently avoid the barrier or reduce the speed or brake; the radar of the invention can make a choice according to the control reference road situation, the vehicle speed and the GPS data.

The invention discloses a forward-looking scanning radar imaging method. The method comprise the steps of initializing imaging system parameters; performing range pulse compression on echo data; subjecting a radar right forward-looking area to super-resolution imaging processing; performing back projection imaging processing on a large-azimuth area; and splicing imaging results of the two areas. According to the forward-looking scanning radar imaging method, an ill-posed problem regularization method is utilized, and accordingly, the azimuth resolution is improved, and a back projection algorithm is combined to improve the azimuth resolution of the large-azimuth area. The two imaging results are spliced into a complete scene image, so that the forward-looking scanning radar imaging scene range is expanded, and not only the defect that synthetic aperture radars cannot perform forward-looking imaging is overcome, but also the problem that azimuth imaging scene ranges of prior forward-looking scanning radars are small is solved.

An automotive radar system includes a beamformer circuit and a beamcombiner circuit. The beamformer circuit forms a plurality of antenna beams at a plurality of beam ports. The beam combiner circuit receives the beams provided thereto from the beamformer circuit and combines the beams to provide a desired number of beams, with each of the beams having a desired beam shape. In one embodiment, the beamcombiner provides first and second end beams having a beamwidth which is less than a beamwidth of middle beams.

The invention discloses an MIMO radar detection method based on double optical frequency combs and difference frequency multiplexing. According to the method, an existing MIMO radar detection technology based on microwave photon orthogonal difference frequency multiplexing is improved, and M paths of modulated optical signals of a transmitting end are generated through the following method: firstly, an optical carrier is divided into an upper path and a lower path; The local oscillator signal is used for carrying out modulation processing on the uplink optical carrier wave to generate a firstoptical frequency comb signal, and the intermediate frequency signal and the intermediate frequency linear frequency modulation signal are used for carrying out modulation processing on the next optical carrier wave to generate a second optical frequency comb signal; After the first optical frequency comb signal and the second optical frequency comb signal are coupled into one path, the first optical frequency comb signal and the second optical frequency comb signal are divided into M paths of modulated optical signals respectively consisting of a single intermediate frequency linear frequencymodulation spectrum line and a single local oscillator signal spectrum line through beam shaping filtering. The invention also discloses an MIMO radar detection device based on the double optical frequency combs and the difference frequency multiplexing. According to the invention, the structure of the transmitter can be greatly simplified, the implementation cost of the system is reduced, and the coherence between signals can be effectively ensured.

The invention designs a synthetic aperture sonar imaging method and a system based on frequency division MIMO. The method comprises: a step 101) the front end and the rear end of N receiving arrays are respectively provided with sending arrays, wherein the front sending array and the rear sending array comprise M sending arrays altogether, the sending arrays send signals to underwater targets to be imaged at the same time, and the M is selected to be an integer which is greater than or equal to 2; a step 102) the M sending signals received by each array element of the N receiving arrays are separated in a frequency domain so that M-ary signals are obtained, and the M-ary signals of all the receiving array elements are moved to a common frequency band in a spectrum shifting mode so that N*M-ary echo signals are obtained; and step 103) the obtained N*M-ary echo signals are rearranged in an azimuth, sampling devices of an equivalent single wave beam synthetic aperture sonar are correspondingly obtained respectively, and finally focusing imaging is performed on equivalent single wave beam signals. With movement of a basic array, frequency bands of the signals sent by different sending array elements of the sending arrays can change in an alternating way according to requirements of movement compensation. A survey and mapping band can be further widened by the synthetic aperture sonar imaging method and the system under the premise of maintaining an azimuth resolution so that survey and mapping efficiency is enhanced.

The invention provides a looking-around synthetic aperture imaging radar. The imaging radar comprises a launch unit 1, a receiving, amplifying, down-conversion and filtering unit 2, a signal processing and imaging unit 3, a display unit 4, a radio frequency signal generating unit 5, a control unit 6 and a power device 7 controlling rotating of a receiving antenna and a transmitting antenna. The looking-around synthetic aperture imaging radar is installed on a top platform of a ship, the transmitting antenna transmits electromagnetic waves to the periphery of the ship in the 360-degree direction, the receiving antenna receives electromagnetic wave signals reflected back by targets and sea waves and performs amplifying, down-conversion and sampling on the signals, and after arc synthetic aperture imaging signal processing, imaging processing and the like are preformed, an image display circuit displays the targets and the sea state information around the ship. The looking-around synthetic aperture imaging radar can replace an S/X wave band ship navigation radar widely applied currently and is used for guiding the ship to sail, ship collision is avoided, meanwhile, the looking-around synthetic aperture imaging radar has the function of inverting ocean kinetic parameters (waves and currents) around the ship, and therefore safety of navigation of the ship is ensured.

The invention provides a method for amplitude/phase correlation joint detection of a response signal, and aims to provide a method capable of effectively detecting a coded modulation pulse signal. Themethod can be realized through the following steps: performing digital down-conversion on three paths of intermediate frequency signals received by a sum channel, a difference channel and an omnidirectional channel in a signal processing module to a baseband, generating orthogonal sine and cosine signals by using a DDS in an FPGA, multiplying the sine and cosine signals by the intermediate frequency signals respectively, performing low-pass filtering to obtain an orthogonal I baseband signal and a Q baseband signal, respectively carrying out phase and amplitude correlation accumulation on thebaseband signals according to the information coding code words to form an aligned sum channel phase correlation peak and amplitude correlation peak, respectively carrying out fixed threshold judgment on the sum channel phase correlation peaks and carrying out self-adaptive threshold judgment processing on the amplitude correlation peaks to form a pulse binarization signal and a pulse effective signal , and performing single pulse processing and receiving discrimination inhibition processing to complete one-time detection of the target response pulse signal.

The invention relates to a method for designing a detection radar antenna of road traffic vehicle flow, which is concretely embodied by a design embodiment. The invention uses an optimized demonstration method to determine the requirements for the indexes of the detection radar antenna of the road traffic vehicle flow, points out the defects of designed antennae in the prior similar radar products, and provides a basic microstrip array antenna of a shunt feed type. Accordingly, a design scheme and a method of two microstrip array antennae of a shunt feed type are provided, and a concrete design result is provided. The method provided by the invention is proved to be capable of generating the antennae more suitable for the need of a detection radar of the vehicle flow and achieving the comprehensive aim of high performance, low price and small size.

The invention relates to the technical field of radio positioning, in particular to a time division multichannel random code phase-modulation shipborne collision-proof radar. A mast or the top of a ship is provided with a receiving/emitting two-purpose quasi-optical integrated dielectric lens antenna annular array; a DSP encoder pulses perform scanning so as to omni-directionally guard against a target possibly collided on a water surface; data of a water photographic sensor, a ship speed sensor and a global positioning system (GPS) sensor access an MCU control time division circuit to generate time division millimeter-wave multichannel random codes for phase modulation, and are emitted through an upconverter, an R/T3, a frequency multiplier and power amplifier, an R/T2, an optical circulator, a beam switch and an antenna array; and back waves are subjected to processing control in the DSP and the MCU through the antenna array, the beam switch, the optical circulator, an R/T1, a low noise high frequency amplifier, a fourth-harmonic mixer, an intermediate frequency amplifier, a time division circuit, and a related multichannel signal extraction module. The radar ensures that adjacent ships in the same water area sail without mutual interference and operate in a coexisting way, has high electromagnetic compatibility EMC, inhibits false-alarm and determines positions, distances and relative speeds of targets through the DSP when meeting multiple targets, displays three-dimensional images and identifies a target closest to the ship through a CRT, performs the audible and visualalarm if the distance of the target is smaller than a safety distance, intelligently avoids a barrier or reduces speed if the distance of the target is approximate to a danger distance, and controlsand references the water photography to combine the ship speed and the current position data provided by the GPS to make a choice, thereby obviously improving the sailing safety of the ship.

The invention relates to an improved dimension-reduction space-time adaptive processing-based ship-borne high-frequency ground wave radar sea clutter suppression method and belongs to the clutter suppression field. The objective of the invention is to solve the problems of large calculation amount and poor clutter suppression effect of an adaptive processing algorithm in the prior art. The improved dimension-reduction space-time adaptive processing-based ship-borne high-frequency ground wave radar sea clutter suppression method includes the following specific steps that: step one, distance transformation and Doppler transformation are performed on high-frequency ground wave radar echo baseband signals, so that distance unit and Doppler unit data can be formed; step two, azimuth processing is performed on the data of any one distance unit and any one Doppler unit through utilizing the MUSIC algorithm; and step three, dimension-reduction space-time adaptive processing is performed on the data which have been processed by the MUSIC algorithm, so that sea clutter can be suppressed. The improved dimension-reduction space-time adaptive processing-based ship-borne high-frequency ground wave radar sea clutter suppression method of the invention is applied to the clutter suppression field.

The invention relates to a wave beam forming method. The wave beam forming method is characterized in that Fourier transform analysis of data received by a receiving array can be carried out to realize phase compensation and accumulation; conjugate multiplication of the accumulated data can be carried out, and the energy of the orientation theta can be acquired; various array element receiving data covariance matrixes of the frequency f can be calculated, and the first covariance matrix can be recorded; the M order sensor cross-correlation processing of the first covariance matrix can be carried out to acquire the virtualized linear array; the routine wave beam forming of the virtualized linear array can be carried out, and the target orientation estimation can be carried out, and then the energies of various array elements of the virtualized linear array on the orientation theta can be acquired; various array element receiving data covariance matrixes of the virtualized linear array of the frequency f can be calculated; whether the main lobe width of the current M order sensor cross-correlation CBF on the 3dB reaches the resolving ability required by the user can be determined, when the requirement is not satisfied, the array element receiving data covariance matrixes of virtualized linear array of the frequency f can be used as the first covariance matrix, and the M order sensor cross-correlation can be repeated after the M is increased by 1, otherwise the operation is ended.

The invention relates to an arc aperture radar imaging method based on antenna phase pattern compensation and a radar. The invention discloses an arc aperture radar imaging method based on antenna phase pattern compensation. The method comprises the following steps: S1, obtaining a radar antenna phase characteristic matrix; S2, fixing an arc aperture radar at a preset position, and performing imaging network subdivision on a radar detection area; S3, calculating a distance delay, an azimuth angle and a pitch angle of each imaging pixel point; S4, calculating to obtain a phase compensation factor of each pixel point; S5, performing space-variant compensation on each imaging pixel point at the same time, and further obtaining a sub-image of the current arc synthetic aperture according to thephase compensation matrix; and S6, coherently superposing the sub-images obtained by the arc synthetic apertures to obtain a final image. Phase inconsistency compensation is performed on each formedimaging pixel point so that Arc-SAR detection is enabled to break through the limitation of the 3dB beam angle of the antenna and the Arc-SAR imaging accumulation angle can be increased.

The invention provides a portable high-frequency surface wave radar wave height inversion method which comprises the steps of firstly performing channel calibration on two monopole cross loops, and utilizing a traditional Barrick method, and obtaining a wave height inversion result at a short-distance element position; then calculating the ratio between a one-order peak and a two-order peak of the radar, and performing orientation by means of a MUSIC algorithm; and finally fitting the ratio between the one-order peak and the two-order peak through using the wave height which is obtained through a Barrick method, and obtaining the final output wave height of the radar. The portable high-frequency surface wave radar wave height inversion method increases measurement precision and measurement distance of wave height. Compared with a common one-two-order peak ratio algorithm, the method does not require calculation of a fitting coefficient by means of prior information such as float and satellite so that the wave height and the wave field can be acquired in real time.

The invention discloses a spaceborne multi-baseline holographic SAR imaging method, which realizes 360-degree omnibearing imaging based on multiple navigation geosynchronous orbit baselines. The method comprises the following steps: S1, an orbit model for geosynchronous orbit spaceborne holographic SAR imaging is constructed; S2, based on the orbit model and an imaging geometric model of the geosynchronous orbit spaceborne holographic SAR imaging, a geosynchronous orbit spaceborne holographic SAR echo signal model is constructed; S3, two-dimensional holographic imaging is carried out; S4, a three-dimensional imaging sparse basis is constructed through constructing an altitude sparse basis; S5, the altitude of a ground target is reconstructed by using a compressed sensing reconstruction algorithm; and S6, a holographic image is displayed. The problems that the airborne platform has a small detection range, the detection area is limited, and the holographic imaging quality is affected bythe movement of a carrier and the like can be solved.

The invention discloses a vehicle-mounted MIMO radar random coding waveform modulation method, and belongs to the field of millimeter wave radars. The method includes the following steps: setting a radar to be in a random coding mode; by arranging a random signal generator, when a radar signal is transmitted, resetting the random signal generator, and generating a group of random codes; after a random code is generated, writing the random code into a register, wherein when the radar transmits a radar signal every time, the radar signal is modulated by calling the code in the register; and inputting the demodulated data in the radio frequency chip into a decoder to generate a decoded receiving signal, so that a receiving end can receive an echo signal reflected after the emitted radar signal encounters an obstacle. According to the invention, each transmitted pulse initial phase is randomly coded in the processor, and transmitted signals of different codes do not interfere with each other, so that a plurality of millimeter wave radars can be used in the same environment, the robustness of the system is improved, and the anti-interference capability of the rail transit radar can be greatly improved.

The invention provides a method and a system for improving SAR (Synthetic Aperture Radar) azimuth resolution or detectability through aperture segmentation. According to the embodiment of the invention, the system for improving the SAR azimuth resolution or detection capability through aperture segmentation can comprise an aperture coding signal generation unit, a transmitting assembly, an antenna, a receiving assembly, a data acquisition unit, a decoding processing unit, an imaging processor, a control unit and the like. The method and the system for improving the SAR azimuth resolution or the detection capability by segmenting the aperture have the advantages that the theoretical limitation of the antenna size on the traditional strip SAR imaging resolution can be broken through, a strip SAR image with high azimuth resolution can be obtained, or the signal-to-noise ratio of the strip SAR image can be enhanced, the detection performance of the SAR system can be improved, and the like.

The invention proposes a ship length calculation method based on observation data of a microwave scatterometer. The method comprises the following steps of performing cone scanning on a ship target bythe microwave scatterometer through a fan-shaped beam, and obtaining a plurality of groups of observation data of the ship target; calculating an included angle between a ship and the movement direction of a satellite according to the time delay, different observation azimuth angles and the Doppler frequency in the observation data; calculating the projection length of the ship in an echo direction according to a ship one-dimensional range profile on a certain observation azimuth angle in the observation data; and calculating the length of the ship according to the included angle between theship and the movement direction of the satellite and the projection length of the ship in the echo direction. According to the ship length calculation method based on the observation data of the microwave scatterometer provided by the invention, the sea surface detection range can be expanded by adopting the fan-shaped beam; the range resolution can be improved by using a broadband signal, and theazimuth resolution can be improved by using a circular scanning technology; and by at least four times of observation on the detected same target, the movement direction of the ship can be accuratelycalculated, and high-precision calculation on the ship length is realized.