72results about How to "High distance resolution" patented technology

The invention discloses a multifrequency phased array ultrasonic Doppler flow detection system and a multifrequency phased array ultrasonic Doppler flow detection method. The system comprises a central control processor, a frequency synthesizer, a transmitting part, a receiving part and a display, wherein the transmitting part comprises a transmitter, a power distribution network, a beam control network, a first beam subarray and a second beam subarray; the receiving part comprises a first beam receiver, a second beam receiver, a multi-beam forming network and a signal processor. The system is characterized in that the central control processor is respectively connected with the frequency synthesizer, the transmitter, the power distribution network, the beam control network, the first beam receiver, the second beam receiver, the multi-beam forming network and the signal processor. In the detection method of the system, beam deflection and dynamic focusing are realized through the phased array technology, multi-directional and multi-depth positions can be measured on the cross section of an integral pipeline, and by a mode of adjusting beam scanning dynamically, the processing timeof the beam scanning is reduced, and the measuring accuracy is improved.

It is an object to provide an optical refractometry measuring method and an optical refractometry measuring device for making it possible to obtain high precision regardless of a measuring distance. The optical refractometry measuring method and the optical refractometry measuring device, which measures a rear scattering light intensity distribution of a measuring subject in a light propagating direction by using an optical frequency domain refractometry method (OFDR), is characterized in that a coherence monitor (12) is prepared to monitor a coherence characteristic of a frequency sweeping light source (1) and a measured result in a measuring unit (11) is corrected in accordance with the monitored result.

The invention relates to method for measuring synthetic aperture sonar movement error and underwater sound channel error. The invention employs an irradiation matrix which is arranged along platform trace and different phase center to irradiate plural orthogonal signal with same frequency at the same time.

The invention discloses a microwave photon dual-band radar detection method. Two different intermediate frequency linear frequency modulation signals are utilized to perform polarization multiplexingmodulation of retaining positive and negative second-order sidebands on optical carriers, and optical carrier linear frequency modulation signals only retaining positive and negative second-order sidebands are generated on two cross polarization states of obtained modulated optical signals; after the modulated optical signals are converted into electrical signals, quadruplicated frequency linear frequency modulation signals of two bands contained in the electrical signals are separated, and serve as radar detection signals to be transmitted to a target; and at the same time, the electrical signals of the two bands reflected by the target are combined into one path, the modulated optical signals serve as reference optical signals, frequency conversion and dechirping processing of an opticaldomain is performed on the combined electrical signals to obtain two intermediate frequency signals carrying information of the target, and the information of the target is extracted from the two intermediate frequency signals. The invention also discloses a microwave photon dual-band radar. The microwave photon dual-band radar detection method and microwave photon dual-band radar provided by theinvention have the advantages of a microwave photon technology and a dual=band radar technology at the same time, is simple in implementation structure, and is high in detection efficiency.

The invention discloses a radar detection method based on microwave photon frequency multiplication and orthogonal demodulation. The method includes: modulating an intermediate-frequency linear frequency modulation signal onto an optical carrier to generate a reservation carrier and a modulation optical signal of a unilateral second-order sideband; dividing the modulation optical signal into two branches, and emitting one optical signal after being converted into an electrical signal and serving as a radar detection signal to a target; using a target echo signal to perform electro-optical modulation on the optical carrier to acquire an optically loaded echo signal; taking the other modulation optical signal as a reference optical signal to perform orthogonal demodulation on the optically loaded echo signal to acquire two orthogonal intermediate-frequency signals carrying target information, and extracting the target information from the orthogonal intermediate-frequency signals. The invention further discloses a radar detection device based on microwave photon frequency multiplication and orthogonal demodulation. The radar detection device has the advantages of both microwave photon technology and orthogonal demodulation and is simple in realization structure and high in detection efficiency.

The invention discloses an optimized display device and an optimized display method for a range-gating super-resolution three-dimensional imaging distance map. The device comprises a pulse laser device, a gating and imaging apparatus, a time sequence controller, a PC (personal computer), a three-dimensional imaging module and an optimized display module. Based on the device, the invention discloses the optimized display method for the range-gating super-resolution three-dimensional imaging distance map, wherein a slice image with low bit depth is replaced with a slice image with high bit depth to obtain a three-dimensional grey distance map with high bit depth, and the distance resolution is improved; in order to vividly show more details, during pseudo-color processing of the distance map with high bit depth, the distance map with high bit depth is linearly normalized to 256-level grey level, and equal-density pseudo-color coding is performed. On the basis of improving the three-dimensional imaging distance resolution to the greatest extent, equal-density pseudo-color coding display of the range-gating super-resolution three-dimensional imaging technology is realized.

The invention discloses a device for generating broadband chaotic laser, which is characterized in that chaotic laser output by a chaotic laser source 1 is divided into two paths: one path is converted into an electric domain chaotic signal by a photoelectric detector, and the electric domain chaotic signal is amplified by a radio frequency amplifier to be used as radio frequency input of a phasemodulator in a chaotic laser source 2; the other path is used as broadband chaotic laser finally generated by the chaotic laser source 1; a phase modulator output optical signal in the chaotic laser source 2 is also divided into two paths: one path is injected into a semiconductor laser in the chaotic laser source 1; and the other path passes through a dispersion module and then is used as broadband chaotic laser finally generated by the chaotic laser source 2.

The invention provides a method and device for detecting the shielding state of an automobile radar, and the method comprises the steps: transmitting a first linear frequency modulation signal, the frequency modulation bandwidth of which is a first preset value, to a preset direction through a millimeter-wave automobile radar; wherein the numerical value of the first preset value ranges from 0.1 GHZ to 12 GHZ; receiving a first reflection signal corresponding to the first linear frequency modulation signal through a millimeter wave automobile radar; detecting the intensity of the first reflection signal; and determining the shielding state of the millimeter wave automobile radar according to the intensity of the first reflection signal. According to the embodiment of the invention, the frequency modulation slope of the millimeter-wave radar is set, so that the distance resolution of the millimeter-wave radar can distinguish obstacles in a short distance of the millimeter-wave radar, the detection mode is simple, and the reliability is high.

The invention provides a method for separating precipitation echoes and sea surface backscattering in the echo signals of a scatterometer. Pulse compression is carried out on the received echo signals to output compressed pulse signals, minor lobe restraining is carried out on the compressed pulse signals through a frequency domain windowing algorithm, the coupling of distance minor lobes existing in precipitation echo signals and sea surface echo signals is eliminated, the time domain aliasing of precipitation and the sea surface is effectively separated, Doppler frequency correction and energy decrement compensation are carried out in a frequency domain, effective precipitation and sea surface backscattering coefficients can be extracted and synchronously inverted from complex air-sea boundary mixed echo signals, the mutual influence can be eliminated or compensated, and the precipitation echoes and sea surface backscattering can be effectively separated.

The invention discloses a radar and a vehicle. The radar includes at least one transmitting antenna for transmitting an electromagnetic wave signal to detect a target object around the radar; at leastone receiving antenna for receiving an echo signal, the echo signal being a signal fed back by the target object around the radar after receiving the electromagnetic wave signal transmitted by the transmitting antenna, and the echo signal carrying information of the target object around the radar; and a conversion module for switching a remote detection mode and a proximity detection mode of theat least one transmitting antenna in an azimuth direction, and switching the remote detection mode and the proximity detection mode of the at least one receiving antenna in the azimuth direction. Theinvention solves the technical problem that the distance resolution of the radar is low in the related art.

A novel and useful system and method by which radar angle and range resolution are significantly improved without increasing complexity in critical hardware parts. A multi-pulse methodology is described in which each pulse contains partial angular and range information consisting of a portion of the total CPI bandwidth, termed multiband chirp. Each chirp has significantly reduced fractional bandwidth relative to monoband processing. Each chirp contains angular information that fills only a portion of the 'virtual array', while the full virtual array information is contained across the CPI. This is done using only a single transmission antenna per pulse, thus significantly simplifying MIMO hardware realization, referred to as antenna-multiplexing (AM). Techniques for generating the multiband chirps as well as receiving and generating improved fine range-Doppler data maps. A windowing technique deployed in the transmitter as opposed to the receiver is also disclosed.

The present invention relates to a three-dimensional imaging photon counting system using N-fold pulse coding and a counting method. The system includes a total controller, a signal generator, a pulselaser, a transmission optical system, a receiving optical system, a Gm-APD array detector, and a TCSPC (time-correlated single photon counter) and a signal processing unit. According to the method ofthe present invention, the total controller controls the signal generator to generate N-fold pulse signals; the N-fold pulse signals are converted into pulse optical signals through the pulsed laser;thee pulse optical signals hit a target object through the transmission optical system; the energy of echo pulse signals reflected by the target object is collected by the receiving optical system; the echo pulse signals irradiate the Gm-APD array detector; signals generated by the detector pass through the TCSPC (time-correlated single photon counter); counted signals are transmitted to the signal processing unit for time correlation and solution; and a counting result is transmitted to the total control module, and the total control module outputs a result. With the counting method of the invention adopted, the problems of strength information loss and incapability of resisting environmental interference in the prior art can be solved.

The invention relates to the field of radar signal processing technology and particularly relates to a radar digital signal processing method and a device thereof. The basic principle of the radar digital signal processing method and the device thereof is that: time sharing processing is conducted to intrapulse sampling data of the linear frequency-modulated interruptive-continuous wave radar to separate original signals which have distance aliasing in the frequency domain by time, and then the separated signal spectrum is recombined to be restored to a spectrum form that has no distance aliasing. The method, differing from traditional methods that only use FFT to obtain an A-type spectrum, conducts the time sharing processing to intrapulse echoed signals. The method is characterized in that the A-type spectrum having no distance aliasing can be obtained from signals having distance aliasing and the range resolution can be increased.

The invention discloses a human body breathing and heartbeat signal detection method and system based on UWB (ultra wide band) radar. The method comprises the following steps: the UWB radar transmitssignals to a human body; the UWB radar receives a target echo signal, and a two-dimensional echo data matrix is obtained after the target echo signal is processed; a direct current component is removed from the two-dimensional echo data matrix, and windowing pulse pressure processing is carried out along the distance direction to obtain a preprocessed matrix; fixed clutters of the preprocessed matrix are removed, and target distance locking is completed through constant false-alarm rate detection; and a weight vector is introduced, and sparse reconstruction is completed through an OMP algorithm to obtain target breathing and heartbeat signals. The human body breathing and heartbeat signal detection method and system based on the UWB radar can accurately extract and separate respiration andheartbeat signals from the echo signals so as to realize non-contact heartbeat and respiration monitoring of the human body.

The invention relates to a DMD (digital micromirror device)-based four-dimensional laser radar imaging device and a DMD (digital micromirror device)-based four-dimensional laser radar imaging method. The device comprises a transmitting device, a target fixed at the light outgoing end of the transmitting device, a first converging lens fixed on the reflected light path of the target, a digital micromirror device (DMD) fixed on the convergent light path of the first converging lens, a second converging lens fixed on the reflected light path of the digital micromirror device (DMD), a receiving device fixed on the convergent light path of the second converging lens, a frequency mixer connected with the receiving device, an intermediate-frequency amplifier connected with the frequency mixer, a quadrature phase detector connected with the intermediate-frequency amplifier, and a signal processing device connected with the quadrature phase detector; and the device also comprises a high-stabilization signal source which is connected with the transmitting device, the frequency mixer and the quadrature phase detector, and a synchronization device which is connected with the transmitting device, the digital micromirror device (DMD) and the signal processing device. The invention also discloses a DMD (digital micromirror device)-based four-dimensional laser radar imaging method. The imaging device and imaging method of the invention have the advantages of excellent effects of detection of targets which are distributed discretely and continuously distributed, high imaging speed and high image resolution.

The invention discloses a range gating super-resolution three-dimensional imaging method based on spatial differencing shaping. The method comprises the following steps: acquiring a first slice image used for three-dimensional reconstruction; building a first space energy envelope shaper in space overlapping with the first slice image; adopting the first space energy envelope shaper to carry out space difference shaping treatment to the first slice image, so as to obtain a first new slice image; obtaining two new slice images with overlapped spaces by adopting gating delayed stepping treatment according to the former step, and carrying out range gating super-resolution three-dimensional reconstruction on the basis of the new slice images. The equivalent narrowing laser pulse durations of the new slice images are half of that of the original laser pulse duration, so that the purposes of narrowing laser pulse duration and improving range resolution are achieved. According to the method provided by the invention, the limitation of the minimal pulse duration of an impulse laser is broken, three-dimensional imaging in higher range resolution is achieved, and the application of range gating super-resolution three-dimensional imaging is developed.

The invention discloses a radar device and a detection device. The radar device comprises at least one transmission antenna and at least one reception antenna, wherein the transmission antenna is a first broadband antenna and is used for transmitting a detection signal to detect a target object, the reception antenna is a second broadband antenna and is used for receiving an echo signal, the echosignal is fed back by the target object after the detection signal transmitted by the transmission antenna is received, and the echo signal contains the information of the target object. The radar device is advantaged in that a technical problem of low distance resolution of a radar device in the prior art is solved.

The invention discloses a monopulse radar non-blind area distance measurement method and system with a protection channel. The system comprises a slot array main antenna, a protection antenna, a tuner, a circulator, an intermediate-frequency receiver, a signal processor, a secondary power source and a transmitter. The system is a monopulse system; the slot array main antenna periodically transmitshigh-frequency pulse signals, and the protection antenna receives target echo signals in real time; transmitting and receiving are carried out correspondingly, so that transmitting and receiving canbe separate; when no distance measurement blind areas exist, sum channel, azimuth difference channel and pitch difference channel data are formed by echoes received by the slot array main antenna, thesum channel, azimuth difference channel and pitch difference channel data are adopted to perform target distance measurement; when a distance measurement blind area exists, the slot array main antenna is used as a transmitting antenna, and the protection antenna receives echo data, and therefore, protection channel data can be formed; the protection antenna carries out real-time receiving to realize non-blind area distance observation, and meter-scale distance measurement requirements can be met; and finally, distance measurement is performed through a pulse method, and distance measurement precision is improved through pulse compression, so that radar distance measurement precision requirements can be met.

The invention discloses a whitening filtering-based anti-interference method for a frequency-agile radar. The implementation process of the method includes the following steps that: echo signals containing a target object to be detected, main lobe interference and noises are received; mixed baseband echo vectors are arranged so as to form a baseband echo matrix; the covariance matrix of the baseband echo matrix is calculated, and generalized eigenvalue decomposition is performed on the covariance matrix; an eigenvalue threshold is set according to a maximum eigenvalue; all eigenvalues larger than the eigenvalue threshold and eigenvectors corresponding to the eigenvalues are selected so as to form a whitening matrix; the whitening matrix is multiplied by the baseband echo matrix, so that whitening filtering can be performed; and the one-dimensional range image of a target is obtained by means of fast Fourier transform (FFT). With the method of the invention adopted, the energy of densefalse target interference can be suppressed with the echo energy of a target retained. The method can be used for improving the target detection probability of a radar.

The invention discloses a super-resolution vertical detection method for an ionosphere Es layer, which comprises the following steps: transmitting a short wave signal to the Es layer in the vertical direction by using a vertical measuring instrument in a small-frequency stepping form to carry out frequency sweeping detection,wherein the frequency stepping ensures that imaging blur is not generated through accurate design; and then, carrying out frequency-by-frequency super-resolution distance imaging by adopting a spectrum estimation method by utilizing coherence between short-wave signals with similar frequencies reflected by the same Es layer region, so as to achieve Es layer super-resolution observation and naturally finish frequency dimension smoothing. Compared with the prior art, the method has the advantages that the range resolution of Es layer observation can be greatly improved by only adopting a conventional vertical measuring instrument system without additional equipment and hardware cost, a super-resolution Es layer sweep frequency ionogram can be obtained, and a super-resolution fixed frequency observation result can also be obtained; according to the method, the fine structure, the evolution process and the fluctuation characteristics of the Es layer in the vertical direction can be observed only by using the vertical measuring instrument.

The invention discloses a double-station synthetic aperture radar imaging method based on time reversal. The method comprises the following steps: constructing a double-station synthetic aperture radar system by utilizing an ultra-wideband wireless transceiver module and a stepping motor module; according to the target scattering signal, constructing a frequency domain transmission matrix: SF-MDMand FF-MDM; respectively carrying out singular value decomposition on the two matrixes, and dividing a linear space taking a left singular vector as a substrate into a signal subspace and a noise subspace; constructing SF and FF imaging functions by utilizing the two subspaces; multiplying the two functions to obtain a new imaging function, and realizing high-resolution imaging in each direction by utilizing the imaging function. According to the invention, a double-station SAR array mode in which a transmitter and a fixed receiver move is adopted, the maneuverability and the concealment are stronger, and the measurement is flexible; target detection is carried out by using an ultra-wideband signal, so the robustness is high; by combining time reversal, a new high-resolution time reversalalgorithm is provided, an imaging result with higher resolution can be obtained, an antenna array is not needed for multiple times of transceiving measurement, and the application range is wide.

The invention discloses a V-FM signal system ISAR two-dimensional imaging method. The method comprises the following steps of first step, carrying out dual-channel solution line frequency tuning processing on a V-FM signal echo; second step, carrying out Fourier transform on solution line frequency tuning signals corresponding to dual channels, then carrying out frequency domain overturn processing on one channel of signals, and superposing the signals and the other channel of signals so as to synthesize a target high-resolution one-dimensional distance image; and third step, carrying out azimuth compression on the target high-resolution one-dimensional distance image and acquiring a target ISAR two-dimensional image. The method possesses characteristics that a production technology is simple and processing precision is high. By using the method, a detection distance can be enlarged, distance resolution can be increased and a problem that distance and speed combination measurement is fuzzy can be solved.

The invention provides a radar target tracking method. The radar target tracking method comprises the following steps of: receiving an original echo signal obtained by target scattering of a broadbandsignal by using a plurality of channels; performing digital processing on the original echo signals of the plurality of channels to synthesize a sum signal, and synthesizing the sum signal into a high-resolution range profile; carrying out incoherent accumulation on the high-resolution range profile in a slow time direction to obtain a range power profile; performing first threshold judgment on the distance power image, and screening a first distance unit set; calculating a normalized amplitude variance according to the first distance unit set, performing second threshold judgment on the normalized amplitude variance, and screening a stable scattering point distance unit set; and determining a target center position according to the stable scattering point distance unit set, and performing target tracking. The invention further provides a radar target tracking device, the scattering points are classified on the basis of the normalized amplitude variance of the sum signal, the stable scattering points are screened out, and the target tracking precision is improved.

The invention discloses a single carrier radar communication integrated signal implementation device based on phase jitter, and belongs to the technical field of radar communication. The single carrier radar communication integrated signal implementation device based on phase jitter is suitable for solving the problem that the distance sidelobe level of a radar signal in an integrated signal is too high, and can complete radar detection and communication. The single carrier radar communication integrated signal implementation device based on phase jitter includes a radar transmitting terminal,a communication receiving terminal and a radar receiving terminal, wherein the radar transmitting terminal is used for acquiring an optimal integrated signal matrix hat{S}opt<,> of Ns communication sequences, and the thinking of the single carrier radar communication integrated signal implementation device based on phase jitter includes the steps: acquiring a communication data stream, dividing the communication data stream into Ns communication sequences, and calculating an integrated signal of the Ns communication sequences, wherein Ns is a positive integer greater than 1; according to theintegrated signal of the Ns communication sequences, calculating the autocorrelation sidelobe level vector of the integrated signal of the Ns communication sequences; according to the autocorrelationsidelobe level vector of the integrated signal of the Ns communication sequences, constructing a target optimization function of the Ns communication sequences; and optimizing the target optimizationfunction of the Ns communication sequences to obtain an optimal integrated signal matrix hat{S}opt<.> of the Ns communication sequences.

It is an object to provide an optical refractometry measuring method and an optical refractometry measuring device for making it possible to obtain high precision regardless of a measuring distance. The optical refractometry measuring method and the optical refractometry measuring device, which measures a rear scattering light intensity distribution of a measuring subject in a light propagating direction by using an optical frequency domain refractometry method (OFDR), is characterized in that a coherence monitor (12) is prepared to monitor a coherence characteristic of a frequency sweeping light source (1) and a measured result in a measuring unit (11) is corrected in accordance with the monitored result.

The invention relates to method for measuring synthetic aperture sonar movement error and underwater sound channel error. The invention employs an irradiation matrix which is arranged along platform trace and different phase center to irradiate plural orthogonal signal with same frequency at the same time.

The invention discloses an optical fiber link detection system and a method based on a digital linear frequency modulation signal. The system comprises a digital modulation signal generator, a circulator and a receiver. The digital modulation signal generator is used for generating a detection signal in the form of a digital modulation optical pulse and injecting the detected optical fiber throughthe circulator. The receiver extracts the detected optical fiber features carried by the detection signal from the backscattered signal. The invention utilizes the characteristic that the linear frequency modulation signal has excellent energy gathering in the fractional Fourier domain, by using digital LFM optical pulse as detection signal, LFM signals with different FM ranges are separated fromnoise in backscattered signals, and the characteristics of detected optical fiber are extracted, which can improve the dynamic range and measurement range resolution of optical fiber link detection simultaneously without increasing the cost.

The invention belongs to the technical field of radar signal processing, and particularly discloses a space-time coding-based frequency diversity array radar distance resolution enhancement method, which comprises the following steps of transmitting a linear frequency modulation signal through a frequency diversity array, and obtaining an angle-frequency two-dimensional frequency spectrum of a transmitting directional diagram through a stationary phase principle, designing two-dimensional space-time coding by analyzing the linear relation between the angle and the frequency, shifting effective frequency bands corresponding to the pulses through the two-dimensional space-time coding, and improving the range resolution through coherent pulse accumulation synthesis bandwidth.

The invention discloses an airspace coverage enhancement method based on time diversity array subarray division. The method comprises the following steps of: dividing a transmitting array element of an MIMO radar into a plurality of subarrays; introducing time delay between adjacent sub-arrays, and establishing a sub-array division time diversity array signal model; obtaining a multi-dimensional fuzzy function expression according to the sub-array division time diversity array signal model; according to the sub-array division time diversity array signal model, respectively changing the array element spacing in the sub-array and the spacing between adjacent sub-arrays, and obtaining a sub-array division multi-dimensional fuzzy function expression; and adjusting the airspace coverage range according to the subarray division multi-dimensional fuzzy function expression. According to the method, sub-array division is carried out on a plurality of transmitting array elements, the time delay is introduced between adjacent sub-arrays, the distance resolution can be improved, meanwhile, by changing the distance between the adjacent sub-arrays and the distance between the array elements in the sub-arrays, the distance resolution of the transmitting array elements can be improved, and meanwhile the airspace coverage range of the transmitting array elements in unit pulse time can be enlarged.

The invention discloses a high-order moment-based coded ultrasonic signal pulse flow forming method and circuit, and the method comprises the following steps: generating a coded excitation signal c (t), exciting an ultrasonic transducer to transmit a coded ultrasonic signal e (t) after power amplification, and obtaining a coded ultrasonic echo signal r (t) through an echo receiving circuit; extracting a second moment s (t) of the coded ultrasonic echo signal r (t); converting the second-order moment signal s (t) into a high-order moment signal h (t); performing gain adjustment on the high-order moment signal h (t) to obtain a coded ultrasonic echo signal pulse flow p (t). The implementation circuit of the method comprises a code generation and excitation circuit, an echo receiving circuit,a second-order moment extraction circuit, a high-order moment conversion circuit and a gain adjustment circuit. According to the method disclosed in the invention, an analog circuit is adopted to obtain a high-order moment pulse flow of the coded ultrasonic echo signal in real time, the signal has the characteristics of high signal-to-noise ratio and low sidelobe, and a detection range can be effectively expanded anddistance resolution can be effectively improved during defect detection.