41 results about "Radar resolution" patented technology

Methods and apparatus are provided for radar systems using multiple pulses that are shorter than the expected range delay extent of the target to be imaged. In one implementation, a method for performing radar includes the steps of: transmitting a plurality of pulses, each pulse having a different center frequency and a time duration shorter than an expected range delay extent of a target, wherein a total bandwidth is defined by a bandwidth occupied by the plurality of pulses; receiving reflections of the plurality of pulses; and performing pulse compression on the received pulse reflections to generate a detection signal having a radar resolution approximately equivalent to the transmission and reception of a single pulse having the total bandwidth. In preferred form, the pulses comprise ultrawideband (UWB) pulses each occupying a sub-band of the overall system bandwidth.

The invention relates to a levee hidden trouble integrated non-destructive testing method. Geological radar is adopted to carry out general survey to the levee to find out whether an abnormal levee section exists according to the characteristics of high resolution, high detecting speed, no damage to an object to be tested and high anti-interference capability of the geological radar. At the abnormal levee section, detailed survey is carried out by integrating the characteristics of rich exploration information, convenient interpretation and strong exploring capability of a high intensity resistivity method and the characteristic of a seismic method that the sandy clay physical mechanics characteristics which are relevant to the shearing strength and the compressive strength of the levee sandy clay such as levee crack, collapse and sinkage, etc. can be reflected, and the property and scope of the abnormal section of the levee are determined. The method of the invention overcomes the limitation exists in a single physical geography non-destructive detecting method when levee detecting is carried out, thus roundly and accurately grasping the abnormal information of the levee and realizing the integrated detecting of the levee hidden troubles.

The invention discloses a microwave imaging method based on scenario block sparsity, and relates to a radar imaging technology. The method includes the steps of carrying out sparse observation over a block sparsity scenario in a compression sampling mode by utilizing a fact that the geometry size of a target in an actual imaging scenario is greater than the spatial resolution of high resolution microwave imaging radar and the imaging scenario usually covers multiple radar resolution units, and carrying out an efficient image reconstruction based on the block sparsity of the scenario. The method is different from an imaging method based on matched filtering; a sparse microwave imaging radar is based on sparse signal processing, recovers observed scarsity or transforms a domain sparsity scenario by that the method solves an optimization problem. Under the same sampling condition, the reconstruction of the sparse imaging scenario is more accurate than that of a conventional sparse microwave imaging, and sparser observation over the sparse scenario also can be achieved under the same reconfiguration performance conditions, so that the data rate of sampling is further reduced.

A system, method, and / or apparatus for remote measurement of terrestrial biomass contained in vegetative elements, such as large tree boles or trunks present in an area of interest, are provided. The method includes providing an airborne VHF radar system in combination with a LiDAR system, overflying the area of interest while directing energy toward the area of interest, using the VHF radar system to collect backscatter data from the trees as a function of incidence angle and frequency, and determining a magnitude of the biomass from the backscatter data and data from the laser radar system for each radar resolution cell. A biomass map is generated showing the magnitude of the biomass of the vegetative elements as a function of location on the map by using each resolution cell as a unique location thereon. In certain preferred embodiments, a single frequency is used with a linear array antenna.

The invention discloses a satellite-borne SAR sliding spotlight imaging mode satellite attitude design method. The main thinking of the satellite-borne SAR sliding spotlight imaging mode satellite attitude design method includes the steps: determining a radar and a satellite; setting the radar on the satellite which includes a satellite body and a satellite head; determining the azimuth resolution index of the radar; according to the azimuth resolution index of the radar, calculating a radar resolution improvement factor so as to calculate the position of a radar equivalent rotation center; establishing a satellite body three dimensional coordinate system XYZ, and according to the position of the radar equivalent rotation center, obtaining the Z-axis directional vector in the satellite body three dimensional coordinate system XYZ at t moment; and calculating the Y-axis directional vector in the satellite body three dimensional coordinate system XYZ at t moment, and calculating the X-axis directional vector in the satellite body three dimensional coordinate system XYZ at t moment so as to calculate the roll angle of the satellite, the pitch angle of the satellite and the yaw angle of the satellite, wherein the roll angle of the satellite, the pitch angle of the satellite and the yaw angle of the satellite are the satellite-borne SAR sliding spotlight imaging mode satellite attitude design result.

A method and apparatus is operative for multiple target detection in a radar system which employs a radar waveform of two or more frequency diverse subpulses. The apparatus adds coherent processing of the subpulse echo signals to determine the presence of multiple scattering centers within the radar resolution cell. The subpulses are coherently combined and one can then estimate the number of scattering centers by forming a sample covariance matrix between the subpulse frequency channels and then performing an Eigenvalue decomposition. The resulting Eigenvalues represent the signal strengths of the scattering centers when the associated Eigenvectors correspond to the optimal subpulse weights associated with that signal. A single strong Eigenvalue indicates a single target while two or more strong Eigenvalues or those Eigenvalues larger than the noise related Eigenvalues or a threshold, indicates the presence of multiple targets.

The invention provides a radar-communication integrated realizing method. According to the radar-communication integrated realizing method, based on analysis on the characteristics of the ambiguity function of transmitted signals of a communication system, communication signals are directly transmitted when the number of transmitted code elements in one transmission period satisfies requirement; the communication code elements pass through a pulse type shaping filter; obtained signals are transmitted out through using a transmitter and by means of an antenna; a receiving end carries out radar detection processing on the signals directly using the communication signals; the receiving end carries out demodulation on the signals through a receiver, so that baseband signals can be obtained; the baseband signals pass through a matched filter, so that an output signal to noise ratio is maximum; if a function which is to be realized by the system is a communication function, sampling judgment is performed on the demodulated baseband signals, so that the communication function can be realized through communication code element information; and if a function which is to be realized by the system is a radar function, a certain code element accumulation is performed on the signals, so that high radar resolution can be obtained, and time delay and Doppler frequency are extracted through using related technologies, and a radar detection function can be finally realized.

The invention belongs to the technical field of radar object detection and discloses a radar object detection method based on a blocking and segmenting AIC model. The method comprises the following steps: constructing a blocking and segmenting AIC model and obtaining a radar object echo signal, compressing and observing the radar object echo signal to obtain the observation value of the echo signal and an equivalent measuring matrix; constructing a sparse basis matrix, based on a compressed sensing matrix constituted by the sparse basis matrix and the equivalent measuring matrix, conducting sparse reconstructing on the observation value; conducting coherent integration and constant false alarm rate detection on the estimation value of a sparse coefficient to obtain range-doppler information of the radar object echo signal; based on the range-doppler information of the radar object echo signal, detecting the radar object so as to address the problems of bandwidth-decided radar resolution, excessive sampling frequency and difficulty in hardware realizing due to high resolution, and the problems of large data sampling, transmission, processing and storage. The method also reduces hardware cost.

The invention provides a high-resolution imaging radar for detecting foreign objects of runways. The high-resolution imaging radar comprises a radar rotating unit and a fixing unit. A millimeter wave transceiving module, a transmitting antenna and a receiving antenna are disposed on the radar rotating unit. The millimeter wave transceiving module transmits a millimeter wave signal through the transmitting antenna. The receiving antenna receives an echo single of a target. The echo signal enters the millimeter wave transceiving module to obtain a beat signal. The beat signal is processed by a signal processing module to obtain the distance between the target and the radar. High-resolution imaging detection of a to-be-detected area is achieved by using the millimeter wave frequency modulated continuous wave radar, the radar is high in resolution, the details of the target can be observed clearly, and target detection and identification are facilitated.

A system, method, and / or apparatus for remote measurement of terrestrial biomass contained in vegetative elements, such as large tree boles or trunks present in an area of interest, are provided. The method includes providing an airborne VHF radar system in combination with a LiDAR system, overflying the area of interest while directing energy toward the area of interest, using the VHF radar system to collect backscatter data from the trees as a function of incidence angle and frequency, and determining a magnitude of the biomass from the backscatter data and data from the laser radar system for each radar resolution cell. A biomass map is generated showing the magnitude of the biomass of the vegetative elements as a function of location on the map by using each resolution cell as a unique location thereon. In certain preferred embodiments, a single frequency is used with a linear array antenna.

A method and apparatus is operative for multiple target detection in a radar system which employs a radar waveform of two or more frequency diverse subpulses. The apparatus adds coherent processing of the subpulse echo signals to determine the presence of multiple scattering centers within the radar resolution cell. The subpulses are coherently combined and one can then estimate the number of scattering centers by forming a sample covariance matrix between the subpulse frequency channels and then performing an Eigenvalue decomposition. The resulting Eigenvalues represent the signal strengths of the scattering centers when the associated Eigenvectors correspond to the optimal subpulse weights associated with that signal. A single strong Eigenvalue indicates a single target while two or more strong Eigenvalues or those Eigenvalues larger than the noise related Eigenvalues or a threshold, indicates the presence of multiple targets.

The invention relates to a three-transmitting four-receiving wide beam antenna, which at least comprises a dielectric substrate and a metal ground plate arranged on one side surface of the dielectricsubstrate, wherein the other side surface of the dielectric substrate is further provided with a transmitting unit and a receiving unit, the transmitting unit includes three transmitting linear arrays, both sides of each transmitting linear array are provided with two parasitic linear arrays, and the three transmitting linear arrays are distributed at equal intervals along the transverse directionof the dielectric substrate; the receiving unit includes four receiving linear arrays, both sides of the four receiving arrays are further provided with parasitic linear arrays, and the four receiving linear arrays are distributed at equal intervals along the transverse direction of the dielectric substrate; and both the transmitting linear arrays and the receiving linear arrays are connected with a feed network. The antenna of the invention aims to broaden the beam and improve the resolution of corner radar.

Resolution of a radar operating within a bandwidth is improved by defining a quantity of substantially rectangular sub-band filters to subdivide the bandwidth in the frequency domain into the quantity of sequential sub-bands having a sub-bandwidth. Each signal sent by the radar is associated with a transmission temporal moment. Each of the quantity of return signals received is routed in one to one correspondence to the sub-band filters, each signal being received at a corresponding sub-band filter. The return signals received are summed by synchronizing the associated transmission temporal moment to produce a reconstructed return signal.

The invention belongs to the technical field of radar imaging, and particularly relates to a correlative oil leakage area imaging radar system of an oil pipeline. The correlative oil leakage area imaging radar system is characterized by at least comprising a DDS (direct digital synthesis) linear frequency modulation signal generation circuit, a frequency source, a signal transmitting circuit, a signal receiving circuit and an imaging processing unit. The correlative oil leakage area imaging radar system has no restriction for the radar resolution by using the phase information of echoes.

The invention provides a space-borne synthetic aperture radar ground range resolution representation and parameter design method. According to the method, synthetic aperture time and an emission signal bandwidth can be designed by representation of a long axis ground range resolution rho l and a short axis ground range resolution rho s of an acquired space-borne synthetic aperture radar according to resolution l needed by the radar, and radar related parameters are adjusted, so that the adjusted radar resolution is smaller than or equal to the l. The method overcomes the shortcoming that the ground range resolution is represented by azimuth and range direction ground range resolution, the ground range resolution capacity of the SAR (synthetic aperture radar) can be more comprehensively reflected, and the resolution in all directions of a ground range plane meets system index requirements.

The invention discloses a two-dimensional resource allocation method for networking radar multi-target ISAR imaging, relates to the technical field of phased array radar inverse synthetic aperture radar imaging, and solves the technical problem of how to reasonably allocate time and aperture resources of a radar system for a multi-target imaging task under a radar networking condition so as to improve the overall performance of the radar system. According to the method, on the basis of target feature cognition, requests for radar resolution are determined, time and aperture resources requiredby target imaging are determined by combining a sparse ISAR imaging technology and a radar equation on the basis; and then resource allocation of the networking radar system is realized through a two-dimensional resource scheduling model for multi-target imaging of the distributed networking radar system, and finally, a multi-radar to multi-target inverse synthetic aperture imaging task is realized through alternate observation and acquisition of target echo signals. According to the method, resource allocation is considered from two perspectives of time and aperture, the resource utilizationrate is improved, and the overall performance of the system is improved.

The invention provides a nonlinear frequency stepping method and system for a stepping frequency radar. The nonlinear frequency stepping method comprises a nonlinear frequency stepping criterion, a nonlinear interval broadband spectrum synthesis method and an implementation method of a nonlinear stepping frequency radar system based on a software radio platform. According to the method, radar echocharacteristics under a uniform stepping interval are analyzed; a nonlinear frequency stepping criterion is designed; and the detection area is scanned for the second time to obtain radar echoes, a broadband spectrum synthesis method under nonlinear frequency stepping is designed, and the broadband spectrum under nonlinear frequency stepping is synthesized to obtain radar scattering echoes, thereby achieving the purposes of improving the radar resolution and reducing the sidelobe of a one-dimensional range profile. Implementation schemes of the non-linear stepping frequency radar system basedon the software radio platform are provided, and the implementation schemes comprise a hardware building scheme and platform parameter configuration.

The invention discloses an atmospheric radar image interpolation method and an atmospheric radar image interpolation device based on Fourier spectrum analysis, which obtain spectral characteristics of temporal and spatial variation of echo intensity by utilizing Fourier spectrum analysis, further apply the spectral characteristics to fit observation data discrete points, and then carry out resampling. The atmospheric radar image interpolation method can make structural characteristics of a strong echo region prominent when processing radar echo data with prominent strong echo center characteristics in a convection region, especially can interpolate an strong echo center which cannot be detected due to low radar resolution at a place far away from a radar, provides reference for further identifying position and intensity of the strong echo center accurately, can solidifying an algorithm program of the atmospheric radar image interpolation method into a chip so as to manufacture a chip device which is fast in operation speed and can satisfy real-time requirements.

The invention discloses a method for improving VTS radar resolution. The method mainly comprises a step of shielding a radar echo of a non-specially-focused target object; a step of carrying out position finding and recording on two close-range radar targets; a step of calculating amplitude difference between a wave crest and a wave valley; a step of amplifying wave crest amplitude; a step of carrying out pixel amplitude recalculation and substitution; and a step of setting a fixed threshold and the like. Through the method above, when the distance between the two targets is very close, the radar resolution is improved by amplifying the wave crest amplitude of the target object and through a method of filtering an adhesion part echo by utilizing the fixed threshold, so that limit of hardware of the radar itself can be broken through, target object identification capability is improved, and supervision intensity is improved. The method can be applied to the fields of vessel traffic supervision, custom anti-smuggling, coast guard warning, marine fishery and marine environmental protection and the like; and besides, the method has realistic significance in judging target threat level and ship moving posture and the like under a battle condition.

The invention provides a radar angular resolution test system. The radar angular resolution test system comprises a detection robot used for carrying a radar to be tested to carry out space displacing, an arc guide rail and two corner reflector devices which are both mounted on the arc guide rail and controlled to move along the arc guide rail, the corner reflector devices are provided with cornerreflector assemblies capable of generating an echo signal which can be fed to the radar to be tested when a radar signal is received, according to the radar angular resolution test system, the detection robot is arranged to carry the radar to be tested to carry out space moving, the large-angle guide rail is arranged, the included angle at any angle can be formed between the two corner reflectordevices and the radar to be tested, and the wide-angle radiator resolution test needs can be met.

The invention discloses an FPGA-based range migration compensation system. According to the present invention, the guidance radar signal preprocessing is used for the phase-coherent accumulation and target detection of a subsequent CPU through the processes of frequency domain transformation, matching complex multiplication, migration frequency domain compensation, time domain transformation, fixed-point floating point conversion and the like in an FPGA. The system solves the problem of range migration caused by the high missile-borne motion speed and high radar resolution, realizes the inter-pulse envelope alignment compensation of the low repetition frequency radar within extremely short time, improves the signal-to-noise ratio of the radar signal accumulation, and has better real-time performance and transportability.

The invention discloses an image processing-based high-tension line identification method, which connects a high-tension line in target echo points detected by radar in a mode of image processing, and belongs to the field of high-tension line identification and detection. The method comprises the following steps: taking a radar plot map as input; performing primary plot condensation; performing pro-domain analysis on condensed plots; grading each plot; judging high-tension line towers according to the grades; classifying the mutually adjacent high-tension line towers; searching a high-tensionline tower chain; extending the high-tension line tower chain in a cranio-caudal direction in all plots, and performing inter-frame voting; and displaying an obtained power line distribution area. Byusing the method, the positions of the high-tension line towers are judged according to the distribution characteristics of the high-tension line towers; a continuous high-tension line is searched sothat a high-tension line distribution area is determined; the method has low requirement on radar resolution and by using the method, a target can be detected at a long distance (beyond 1.5 km); and because only the plots are processed, the method has the characteristics of high efficiency, small computation amount, and positive and great practical value.

The invention discloses a radar target extraction method based on edge detection. Radar data are processed in an image mode. The specific implementation processing flow is as follows: the processing flow is as follows; dynamically solving each triggered noise threshold according to the radar echo amplitude; filtering the original data by applying a noise threshold; and performing edge detection onthe filtered data by using a sobel operator, eliminating inaccuracy caused by edge thickness by using a non-maximum suppression part, solving a threshold value by using accumulated residual entropy for an eliminated gradient value, performing further filtering on the edge according to the threshold value, and performing envelope extraction on new edge data to realize radar target extraction. Themethod has the advantages that in a complex environment and under the condition of low radar resolution, the edges in multiple directions are solved from the perspective of envelope, and the edges areeffectively filtered, so that the accuracy of the target is improved, and meanwhile, the probability of target splitting is reduced.

Resolution of a radar operating within a bandwidth is improved by defining a quantity of substantially rectangular sub-band filters to subdivide the bandwidth in the frequency domain into the quantity of sequential sub-bands having a sub-bandwidth. Each signal sent by the radar is associated with a transmission temporal moment. Each of the quantity of return signals received is routed in one to one correspondence to the sub-band filters, each signal being received at a corresponding sub-band filter. The return signals received are summed by synchronizing the associated transmission temporal moment to produce a reconstructed return signal.

The invention relates to a laser radar equation reference height determination method and device for observing aerosol. The method comprises the following steps: determining a height with a signal-to-noise ratio of a laser radar echo signal and a distance correction value meeting a preset condition in each height in a preset height range; wherein the preset height range is set on the basis of searching an atmospheric cleaning layer; each height in the preset height range is selected by taking the highest height in the preset height range as a starting point and taking the laser radar resolution as an interval step length; and based on the height, determining the reference height of the laser radar equation by adopting a backscattering coefficient profile inversion technology. The method for determining the reference height of the laser radar equation is wide in application range, low in cost, simple and effective, and then development of observation of the aerosol vertical profile through the laser radar is promoted.

The invention relates to a time difference ranging radar structure with low power consumption and simple structure, and belongs to the technical field of radar structures and radar ranging. The structure comprises a digital gradient generator, a digital control type oscillator, a power amplifier, a transmitting and receiving antenna, a low-noise amplifier, an envelope detector and a time-to-digital converter. The time difference ranging radar structure can solve the problem that the radar resolution of a frequency modulated continuous wave radar is seriously limited by bandwidth, meanwhile, anoscillator in a transmitter part is controlled by an enable signal, and when a multi-bit digital signal is input, the oscillator only works in a half cycle that the multi-bit digital signal is in anupward gradient, so that the power consumption is greatly reduced; in the receiver part, the demodulation and measurement circuit part adopts an envelope detector to detect the envelope of an echo signal, and adopts a time-to-digital converter to measure the time difference, so that compared with a coherent demodulation and frequency difference measurement method of a frequency-modulated continuous wave radar, the structure is simple.

The invention relates to a radar waveform design method based on a deep neural network. The method comprises the steps of setting four types of environment variables: targets, interference, clutters and noises; respectively designing radar waveforms through utilization of an MI (Mutual Information) criterion and an SINR (Signal to Interference plus Noise Ratio) criterion and obtaining frequency domain energy distribution of the radar waveforms; forming a training set and a testing set; designing a DNNs; training the DNNs through utilization of the training set; and generating the radar waveforms through utilization of the trained DNNs. Compared with an existing radar waveform design method, the method has the advantages that modes of generating signals through utilization of the MI criterion and the SINR criterion can be taken into consideration, radar resolution and frequency domain energy distribution precision are improved, and a great deal of formula derivation resulting from combination of different criteria is avoided.

The invention discloses a method for improving VTS radar resolution. The method mainly comprises a step of shielding a radar echo of a non-specially-focused target object; a step of carrying out position finding and recording on two close-range radar targets; a step of calculating amplitude difference between a wave crest and a wave valley; a step of amplifying wave crest amplitude; a step of carrying out pixel amplitude recalculation and substitution; and a step of setting a fixed threshold and the like. Through the method above, when the distance between the two targets is very close, the radar resolution is improved by amplifying the wave crest amplitude of the target object and through a method of filtering an adhesion part echo by utilizing the fixed threshold, so that limit of hardware of the radar itself can be broken through, target object identification capability is improved, and supervision intensity is improved. The method can be applied to the fields of vessel traffic supervision, custom anti-smuggling, coast guard warning, marine fishery and marine environmental protection and the like; and besides, the method has realistic significance in judging target threat level and ship moving posture and the like under a battle condition.

The invention discloses a distributed compact sensing matrix tracking method based on a cross array radar system, comprising the following steps: (1) obtaining compact sensing matrixes psiX and psiY according to sensing matrixes phiX and phiY corresponding to two arrays in a cross array radar; (2) carrying out processing by an orthogonal matching tracking algorithm to obtain initial estimates S(^)<ini><X> and S(^)<ini><Y> of a correct subspace; (3) forming two candidate column sets f(^)<X> and f(^)<Y> according to all the columns in a plurality of similar column groups corresponding to the initial estimates S(^)<ini><X> and S(^)<ini><Y>, performing union operation on the two candidate column sets to obtain the latest candidate column set f(^), performing permutation and combination on the columns to find a column combination minimizing the residual sum and obtain a correct support set; and (4) obtaining corresponding azimuth angle and pitching angle according to the correct support set. By constructing low-coherence compact sensing matrixes, the problem that a sparse vector cannot be perfectly reconstructed with large probability due to the fact that the original perception matrix has high coherence as the radar resolution increases is overcome, and the result is more accurate through fusion of the information of two columns.