165results about How to "Suppress clutter" patented technology

The invention relates to a radar moving target detection method based on short-time sparse fractional Fourier transform (ST-SFRFT), and belongs to the technical field of radar signal processing and detection. The method comprises the steps of: performing radar echo demodulation and pulse compression to realize high range resolution, and selecting a range unit to be detected; performing spare time-frequency analysis parameter initialization, comprising selection of a short-time window function and a window length and design of a sparse decomposition dictionary; performing ST-SFRFT operation for spare optimization solution, thus completing high-resolution spare time-frequency representation of moving target echo; traversing all range search units, performing moving target signal spare domain detection and estimating a target moving parameter. By adopting a high-resolution spare representation method, high-resolution and low-complexity time-frequency representation of time-varying signals is realized at the time frequency-spare domain; and the method is suitable for analyzing the time varying non-stability of signals, suppresses background clutter while improving energy concentration of moving target signals, and significantly improves the radar moving target detection and parameter estimation capability.

The invention discloses an airborne radar clutter suppression method based on covariance matrix estimation. The idea is that airborne radar pulses z<nl> received by the nth array element at the lth range gate after fast Fourier transform and airborne radar echo z<kl> received by the kth Doppler channel of N array elements at the lth range gate are calculated, and airborne radar etch z'<kl> of the kth Doppler channel and the lth range gate of N array elements after dimension reduction processing and an airborne radar echo clutter covariance matrix R<kl> of the kth Doppler channel and the lth range gate of N array elements are calculated; and an airborne radar echo covariance weight coefficient matrix beta

<kl> of the kth Doppler channel and the lth range gate of N array elements after the pth time of iteration and an airborne radar echo clutter optimal covariance matrix R<^><kl> of the kth Doppler channel and the lth range gate of N array elements are calculated, and airborne radar echo clutter of the kth Doppler channel and the lth range gate of N array elements after space-time self-adaptive filtering processing is calculated so that the range-Doppler spectrum corresponding to array element-Doppler domain airborne radar echo is calculated.

The invention discloses a working environment detection system. The system comprises a smoke signal collection signal, a feedback calibration circuit and an operational amplifier output circuit; the smoke signal collection circuit adopts a smoke signal collector J1 in the model of LB-70C to collect a plant working environment smoke signal; the feedback calibration circuit is divided into two pathsto receive output signals of the smoke signal collection circuit; in one path, a composite circuit is composed of an inductor L1, a resistor R5 and a capacitor C3 so as to filter high-frequency noisein the signal, and a peak detection circuit is composed of an operational amplifier AR2, the operational amplifier AR4 and a diode D3 and the diode D4 to regulate signal peak value; in the second path, a delay circuit is composed of a triode Q1, a resistor R6 and a capacitor C2 to delay the signal, and the operational amplifier output circuit amplifies the signal through an in-phase manner by applying the operational amplifier AR7, and a pai type filter circuit is composed of the inductor L2, the capacitor C7 and the capacitor C8 to filter and output the signal; the smoke status in the working environment of the plant can be monitored in real time, the signal transmission stability is improved at the same time, and the signal frequency hopping and distortion are prevented.

The invention discloses a self-adaptive static human body target positioning method based on EMD for a through-wall radar, relates to a through-wall radar technology, in particular to a static targetdetecting and positioning technology for the through-wall radar, and provides a static target positioning algorithm suitable for the MIMO through-wall radar. The method comprises the steps that received multi-cycle data is subjected to fast time dimension Fourier transform so as to obtain multi-cycle range profiles; then the multi-cycle range profiles are divided into a plurality of column vectorsaccording to range cells, and each column vector data is processed by using an EMD algorithm; the processed range profiles are converted into a frequency domain through slow time dimension Fourier transform, and the range profiles containing the target information are selected in a self-adaptive mode; and finally, fast imaging is carried out through a BP imaging algorithm, and noise and clutter are further inhibited by combining with a PCF algorithm. The method has the advantages that the positioning precision is high, the capability of adaptively processing data can be achieved, and the method can be directly applied to through-wall radar equipment.

The invention discloses a radar clutter time space adaptive pre-filtering method based on sparse recovery, comprising steps of establishing an airborne phased control array radar clutter model, wherein the airborne phased control array radar receives clutter in a detection area in a coherent processing interval, calculating the clutter on a first distance ring, successively calculating the clutter on the first distance ring and a clutter covariance matrix, setting a matrix obtained through arranging a space time guiding vectors, obtaining the airborne phase control radar clutter rank, successively calculating the space time guiding vector and the sparse recovery clutter amplitude corresponding to the clutter on the basis of the sparse recovery, obtaining the coefficient matrix of the airborne phase control radar clutter canceller, performing pre-filtering on the received clutter, obtaining the clutter vector and the target vector, successively calculating a dimension reduction matrix corresponding to the clutter, a clutter dimension reduction vector and a target dimension reduction vector, and then obtaining the adaptive optional weight when the clutter in the airborne phase control matrix radar detection area performs dimension reduction.

The invention discloses an efficient cascading space-time adaptive processing method based on passive detection. Firstly, coherent integration is carried out on time domain pulses; secondly, weight of adaptive digital beam forming (ADBF) of a beam domain is calculated through high-frequency Doppler unit data only comprising interference information; thirdly, ADBF interference restraining is carried out on each Doppler unit; lastly, clutter is restrained through an adaptive double-delay canceller, and coherent integration is carried out on output signals of the self-adaptive double-delay canceller through weighting fast Fourier transform (FFT). By means of the efficient cascading space-time adaptive processing method, interference and clutter can be effectively restrained, the moving-target detection performance can be improved, and engineering implementation is easy because of small operand.

The invention discloses a satellite-borne three-channel SAR-GMTI self-adaptive clutter suppression method and relates to self-adaptive clutter suppression. The method comprises the first step of obtaining distance Doppler domain target echo signals after distance compression, the second step of obtaining distance Doppler domain echo signals after distance compression, the third step of obtaining data X1 of a first distance unit to be detected of three channels, the fourth step of obtaining data of multiple Doppler units subjected to self-adaptive clutter suppression in the first distance unit to be detected, and the fifth step of making the number l of the distance unit to be detected to be increased by one, repeating the second step, the third step and the fourth step until l is equal to L, namely completing clutter suppression of L distance units, and then outputting data Y of the L distance units subjected to clutter suppression. The satellite-borne three-channel SAR-GMTI self-adaptive clutter suppression method is used for suppressing ground clutter received by a three-channel SAR-GMTI system.

The invention belonging to the field of airborne array radar clutter suppression provides an airborne radar clutter suppression method based on launching space-time weight optimization and KA-STAP. On the basis of the traditional KA-STAP, the available freedom degree of a radar transmitting terminal is utilized fully; according to an array structure and clutter prior information, a launching space-time weight vector is designed to suppress mainlobe and sidelobe clutters so as to reducing the received clutter peak energy and keep the complete clutter information estimation prior covariance matrix; and then an estimated covariance matrix is loaded based on the constructed prior covariance matrix and calculation is carried out to obtain a received STAP filter space-time optimal weight. Compared with the conventional launching plus KA-STAP method, the provided method has the following beneficial effect: the launching freedom degree is introduced to reducing the clutter peak energy in echo and reducing the dynamic range of the received signal; and compared with the launching space-time weight optimization method, the provided method has the following advantage: the certain clutter information is kept in the echo and thus the clutter can be suppressed at the receiving terminal by the KA-STAP.

The invention belongs to the technical field of radars and discloses a moving target detection method of an airborne external radiation source radar. The method comprises the following steps: signals received by an airborne external radiation source radar are obtained; two echo signals are subjected to fitting filtering and phase compensation according to a reference signal, and two echo signals subjected to phase compensation are obtained; the two echo signals subjected to phase compensation are subjected to channel registration, and one of the two echo signals subjected to channel registration is deducted from the other, so that an echo signal subjected to clutter suppression is obtained; the echo signal subjected to clutter suppression is then subjected to Doppler migration correction, and a target echo signal subjected to Doppler migration correction is obtained; and the target echo signal subjected to Doppler migration correction is then subjected to distance migration correction, so that a target echo signal subjected to distance migration correction is obtained. The method solves the problem in the prior art that the target detection performance is poor when target migration is not compensated.

The invention relates to the radar anti-interference technical field, in particular to a method for inhibiting ionospheric clutter in portable high frequency groundwave radar. In the invention, a plurality of sets of auxiliary crossed loops are arranged in the vertical direction of original crossed loop antennas of the portable high frequency groundwave radar, adaptive cancellation is carried out on the received signals of auxiliary crossed loop antennas, a main crossed loop and monopole antennas; the received signals of the main crossed loop and the monopole antenna are used as a basic input signal, the difference of the received signals between each auxiliary crossed loop antenna and the main crossed loop antenna are used as a reference signal to input three mutually independent self-adapting filters; an error signal is output from the self-adapting filters to be echoed signals of the main crossed loop and the monopole for inhibiting ionospheric clutter. The invention has the following advantages: an ideal ionospheric clutter reference signal can be obtained and the working efficiency and detection performance of radars can be greatly increased.

The invention discloses a wind farm clutter recognition and suppression method based on a dynamic clutter map. The wind farm clutter recognition and suppression method comprises the following steps of: acquiring and storing M times of scanning data serving as an initial sample by using a radar, evaluating initial sample data, and counting and averaging to form a quasi-clutter map; judging whether wind farm clutter exists in data of each distance unit according to the quasi-clutter map, and marking units in which the presence of wind farm clutter is judged to form a clutter map; matching data obtained by current scanning with the clutter map unit after unit, and eliminating currently-scanned data corresponding to the marked clutter in the clutter map from echo data; and continuously updating a sample for forming the clutter map according to the currently-scanned data to obtain a dynamic clutter map which changes along with the practical environment, and applying the dynamic clutter map to real-time processing of data obtained by each scanning. The recognition result of the wind farm clutter recognition and suppression method based on the dynamic clutter map disclosed by the invention can be applied to recognition and suppression of aviation management monitoring radar wind farm clutter, and the method plays an important role in ensuring aircraft flight safety.

The invention belongs to the technical field of communication, and discloses a clutter inhibition method of an airborne external radiation source radar. The method comprises the following steps: obtaining signals received by the airborne external radiation source radar, wherein the signals comprises reference signals, first echo signals and second echo signals; respectively segmenting the reference signals, the first echo signals and the second echo signals to obtain segmentation reference signals and two paths of segmentation echo signals; according to the segmentation reference signals, respectively performing range-direction compression on the two paths of segmentation echo signals to obtain range-direction compression signals of the two paths of segmentation echo signals; respectively performing phase compensation on the range-direction compression signals of the two paths of segmentation echo signals to obtain phase compensation signals of the two paths of the segmentation echo signals; and performing channel registering on the phase compensation signals of the two paths of the segmentation echo signals, and performing subtraction on the two paths of the segmentation echo signals after the registering so as to inhibit clusters and reserve object information. The method provided by the invention solves the problem of neglect of incomplete cancellation of the clusters during migration of the reference signals in the prior art.

Disclosed are a production method and production device for producing a thin-shaped NdFeB sintered magnet with superior magnetic properties, particularly coercive force and degree of orientation, and an NdFeB sintered magnet produced with said production method and production device. The NdFeB sintered magnet production device is provided with a filling unit (1) that supplies an alloy powder (11) comprising a prescribed amount of Dy to molds (10) and fills the powder to a density in the range of 3.0 to 4.2 g/cm3, an orienting unit (3) that orients the molds (10) filled with the alloy powder (11) in a magnetic field, a sintering furnace (not shown) that with each mold (10) sinters the alloy powder (11) within the molds (10) that have been oriented by the orienting unit (3), and a conveying unit that comprises a belt conveyor and a manipulator (not shown) and conveys the molds (10); to each unit and the sintering furnace. The production device is also provided with coils for thermal orientation (20) that reduce the coercive force of each particle in the alloy powder (11) by heating the alloy powder (11) filled within the molds (10) before and/or after applying the magnetic field in the orienting unit (3).

The invention belongs to the technical field of airborne MIMO (Multiple-Input-Multiple-Output) radar non-adaptive filtering, and discloses a non-adaptive clutter pre-filtering space-time two-dimensional cancellation method for airborne MIMO radar. The non-adaptive clutter pre-filtering space-time two-dimensional cancellation method comprises the following steps: firstly constructing the clutter model of the airborne MIMO radar, obtaining the parameters, such as radar wavelength, pulse repletion rate, radar transmitted waveform and airborne speed in an angle-Doppler domain distribution trajectory, of clutter, and taking these parameters as prior information for the design of an airborne MIMO space-time two-dimensional pulse phase canceller; then using the designed space-time two-dimensional pulse phase canceller for pre-filtering the clutter. Due to the adoption of the method, the target detection performance by using traditional MTI (Moving Target Indication) of cascading is obviously improved compared with traditional MTI without pre-filtering. Through the application of cascading space-time self-adaptive algorithm after pre-filtering, a majority of clutter power is effectively inhibited, and the algorithm performance is improved. The method is suitable for side-looking radar, and similarly suitable for squint radar.

The invention discloses a multi-channel uniformly-accelerated trajectory SAR moving target two-dimensional speed estimation method. The method comprises the following steps: performing multi-channel uniformly-accelerated motion trajectory SAR moving target detection and two-dimensional speed estimation by combining a VSR technology with a time domain backward projection algorithm (BP); firstly imaging multi-channel echo data by utilizing the BP algorithm, and then inhibiting static clutter and estimating the distance speed of the moving target by using the VSAR technology, and then imaging a sub-region through the BP method by using the estimated distance speed and the searched target location range; and inhibiting the clutter of the sub-image by utilizing the VSAR technology, and finallyacquiring an azimuth speed of the moving target by adopting the minimum image entropy method. The invention provides a new moving target detection and two-dimensional speed estimation method for a mobile trajectory platform, the clutter can be effectively inhibited, the location of the moving target and the two-dimensional speed of the moving target can be precisely estimated.

The invention discloses a non-adaptive clutter cancellation method for a vehicle-mounted MIMO radar and mainly solves the problems of low clutter cancellation performance and large computing amount of the prior art. In the invention, the clutter spectrum broadening caused by clutter fluctuation is taken into consideration and more degree of freedom are used, so as to improve the clutter cancellation performance of the prior art considerably. The method comprises: firstly, establishing a matrix vector model of a ground clutter signal, computing a residual clutter signal, minimizing the energy of the residual clutter signal, obtaining a coefficient matrix and consequently obtaining the result of filter design; and secondly, writing echo data of a plurality of continuous pulses as a long vector, and processing clutters by using a filter to cancel a major part of the clutters. The method is used for space-time two-dimensional cancellation of ground clutters before the conventional space-time cascade processing method and the traditional adaptive processing method. The method is suitable for both sidelooking radars and non-sidelooking radars, and has high clutter cancellation performance.

The embodiment of the invention discloses a signal processing method, equipment and a computer storage medium. The method comprises the steps that secondary range dependence (SRD) compensation is performed on a received signal, and a received signal (shown in the description) after compensation is obtained; according to a target with a taper angle psi<0>, a transmitting-receiving Tx-Rx spatial domain transformation matrix B(psi<0>) is acquired based on a formed beam Q<T> in a transmitting spatial domain and a formed beam Q<R> in a receiving spatial domain; according to the velocity v<0> of thetarget, a time domain transformation matrix A(v<0>) is acquired based on Q<D> channels formed around a Doppler domain of the target; based on the Tx-Rx spatial domain transformation matrix B(psi<0>)and according to a preset false target interference elimination strategy, a Tx-Rx spatial domain transformation matrix (shown in the description) after elimination is generated; after the Tx-Rx spatial domain transformation matrix (shown in the description) after elimination and the time domain transformation matrix A(v<0>) are united, dimension reduction processing is performed on the received signal (shown in the description) after compensation through a united transformation matrix T(r<l>,psi<0>,v<0>); self-adaptive weight vectors are generated through a self-adaptive algorithm based on thereceived signal after dimension reduction; and filtering processing is performed on the received signal after dimension reduction based on the self-adaptive weight vectors to obtain data after filtering.

The invention discloses a multifunctional strong shock simulating testing device and method, and relates to the technical field of pneumatic shock equipment. The device comprises a power device, a sliding worktable top, a front baffle, a front baffle buffering cushion, a rear baffle and a rear baffle buffering cushion, wherein the front baffle and the rear baffle are oppositely arranged; a pair ofmutually-parallel slide rails is arranged between the front baffle and the rear baffle; each slide rail is sleeved with at least one linear slide block; the sliding worktable top is arranged on the linear slide blocks in a screwing manner; the front baffle buffering cushion and the rear baffle buffering cushion are correspondingly arranged at the inner side of the front baffle and the inner sideof the rear baffle. According to the multifunctional strong shock simulating testing device and method, a shock response spectrum shocking platform or a high-speed shock cylinder is used for supplyingshock power to the sliding worktable top, and thus twice classic shocks in positive direction and negative direction can be realized by once shocking, and the shock acceleration waveform can be amplified; and moreover, the classic shock and complex instantaneous shock in one direction can also be realized.

The invention discloses a cognitive waveform optimization processing method used for a multi-transmission GMTI (Ground Moving Target Indication) radar system. The method comprises the steps that a distance unit to-be-detected is set as a desired signal; information of a distance unit adjacent to the distance unit to-be-detected is regarded as an interference signal; based on a weight of an initial pulse pressure filter, an initial time domain response output result is obtained; according to prior information, artificial interference is added to a sidelobe area of the initial time domain response output result; a weight of the pulse pressure filter next time is optimally designed by controlling power of the artificial interference; a time domain response diagram inversely matched with an environment is obtained after repeated iterations, that is a low sidelobe is formed in a place with stronger clutter interference; and a higher sidelobe is formed in a place with weaker or no clutter interference. The filter designed by the method takes a template designed according to environment prior knowledge as a reference, the low sidelobe is designed in a strong clutter area, and the high sidelobe is designed in a weak or no clutter area, so that the filter has the adaptive capability, and can inhibit clutter better.

The invention discloses a gesture radar signal processing method based on RDTM and ATM fusion. The method comprises the steps of A, carrying out detection on a gesture, recording an intermediate frequency signal, and carrying out two-dimensional rearrangement and moving target display processing on a one-dimensional intermediate frequency echo; B, performing framing rearrangement to obtain L frames of echo signals; c, performing two-dimensional windowing processing on each single-frame signal; D, performing two-dimensional Fourier transform and modulus operation on the windowed single-frame signal to obtain RDM; E, conducting wavelet decomposition, wavelet coefficient processing and wavelet reconstruction processing on each column of data of the RDM to obtain the reconstructed RDM; F, performing combination and mask processing on the RDM obtained by the L frames of echo signals to obtain an RDTM; G, performing data processing on the intermediate frequency echoes received by all receiving antennas according to a virtual array antenna mode to obtain an ATM; H, performing image fusion on the RDTM and the ATM; and I, completing image classification through a neural network to perform gesture recognition. According to the method, the defects in the prior art can be overcome, and the gesture recognition accuracy is improved by 7.5%.

The invention discloses a moving target detector utilizing time delay FRFT mode difference, and the technology belongs to the field of radar signal processing. The existing moving target detection methods are mainly based on statistical models and fractal and modern signal processing technologies, and the methods have the weaknesses of a narrow range of applications, background clutter, unsatisfactory interference suppression, difficult implementation and the like. The maximum positive value of the FRFT mode difference between a received signal and a time delay signal thereof is adopted as the detection statistical quantity. The detector can suppress the interference and the clutter, improve the signal to noise ratio to a certain extent and effectively detect a moving target under the low signal to noise ratio. As the moving target detector is simple and easy to realize, the moving target detector can be applied in various reconnaissance and surveillance radar signal processing systems, and has the popularization and application value.