38 results about "Coherent processing" patented technology

The invention relates to the technical field of radar information, in particular to a ground clutter suppression method for a ground reconnaissance radar, which comprises the following steps of: firstly, establishing a clutter profile map by using echo data, judging information inside and outside a clutter according to the clutter profile map, and selecting different signal processing flows, namely, adopting a detection channel 1 outside the clutter, adopting a detection channel 2 and a detection channel 3 inside the clutter and adopting a detection channel 2 and a detection channel 3 outside the clutter; after the detection channel 1 passes through the MTD filter, clutter suppression processing is not carried out, and a detection result is output; the detection channel 2 is a coherent processing channel, firstly performs mean filtering processing, then performs coherent processing, performs clutter suppression processing through phasor mean filtering, and outputs a detection result; and the detection channel 3 is a zero Doppler processing channel and is used for detecting a low-speed target in a clutter area, compared with the prior art, the method can reduce Doppler sidelobes as much as possible on the premise of ensuring that the ground clutter height is suppressed, and has the minimum main lobe width and the minimum signal-to-noise ratio loss.

The invention discloses a high-resolution range profile feature retention enhancement method based on iterative weighted sparse decomposition, and the method comprises the steps: obtaining radar echo data collected by a radar receiver within a coherent processing time, and constructing a two-dimensional radar echo matrix composed of a range unit number and a pulse sequence number after range direction matching filtering; representing a two-dimensional radar echo matrix as a superposition relation of adding a low-rank clutter component matrix and a sparse target component matrix; based on the superposition relation, an optimization model is constructed, and the objective function of the optimization model is the sum of the weighted nuclear norm of the low-rank clutter component matrix and the L1 norm of the sparse target component matrix. According to the method provided by the invention, the adaptive weight is applied to the singular value, so that clutters are effectively suppressed under a strong clutter background, and key structure features such as the number, position distribution and relative amplitude relationship of scattering points in the target high-resolution range profile are kept.

The invention provides an extended target phase offset coherent waveform design and efficient accumulation method. The method comprises the following steps: acquiring a pulse signal of a JFPA waveform received by a target, returning echo signals of a plurality of extended targets, and searching a target coarse velocity by using a minimum envelope entropy, constructing a matching function to perform motion compensation on the echo signal to obtain a two-dimensional time domain signal; taking the jitter initial phase of the echo signal corresponding to the reference waveform as a matched filter, and compensating the jitter initial phase of the echo signal corresponding to the coherent accumulation waveform; and designing the echo signal after initial compensation as a coherent echo signal, and performing Fourier transform on the coherent echo signal along slow time to obtain a coherent accumulation result of the target. According to the method, accurate initial phase jitter compensation is completed without target distance information, the method is suitable for an extended target, and after the echo signal of the JFPA waveform is subjected to initial phase jitter compensation, the phase is controlled to be uniform, so that the complexity of FFT coherent processing can be reduced.

A precipitation scanning aperture RADAR system comprises at least one transmitting satellite (TX) and a plurality of receiving satellites (RXs) flying in a multi-static formation. The TX emits fixed frequency, pseudo-random, non-repeating phase modulated RADAR energy. Range and Doppler information is extracted from reflected signals received by the RXs to form coherent 2D along track / vertical images, which are combined into a 3D reflectivity map using a power-based incoherent modeling algorithm, such as a Gaussian mixture model. Embodiments implement a spotlight mode in which, for each RX, a plurality of the coherent 2D images obtained during successive coherent processing intervals (CPIs) are incoherently combined, and the satellites adjust their orientations between each CPI to compensate for satellite movement. Inter-satellite timing synchronization of 10 ns or better is sufficient for forming the 3D reflectivity map. The range and Doppler information can be extracted by concurrently demodulating at a plurality of reference frequencies.

The present application belongs to the technical field of radar imaging and unmanned system integration, and particularly relates to a synthetic aperture radar imaging system and a UAV array SAR image detection method. The UAV array SAR image detection method comprises: S1, issuing an array arrangement form, trajectory design parameters and an imaging mode to a master control UAV; S2, the master control UAV calculates the position, spacing, flight path and beam direction parameters of each UAV; S3, baseband excitation parameters, synchronization signals and attitude control instructions are issued to the UAV detection array; S4, the UAV detection array synchronously transmits radar beams and receives target echoes, and the echo data is returned to a signal processing node; S5, the signal processing node performs coherent processing and SAR image signal processing, and returns the target image to the ground system. The present application realizes coherent synthesis of multiple front-end UAV received echoes and high-resolution image generation, and the image result can be used for tactical identification or geographic situation awareness display.

The application relates to a UAV array dynamic angle of arrival estimation method and system, which comprises the following steps: S1, acquiring array snapshot data after reference channel auxiliary synchronization and waveform compensation; S2, establishing a parameterized space-time coupling phase model in a short coherence processing interval; S3, based on the array snapshot data, obtaining a single-channel input sequence through beam forming, and estimating a radial parameter pair by using time domain atom matching filtering; S4, based on the radial parameter pair, performing common time phase compensation on the array snapshot data to obtain a compensated snapshot matrix; S5, performing two-dimensional correlation calculation by using a space-time steering atom to estimate an angle parameter pair; S6, constructing a complete space-time dictionary atom, and estimating a complex amplitude by using a least square criterion; and S7, performing successive interference cancellation to update a residual error. Compared with the prior art, the application has the advantages of keeping low signal-to-noise ratio coherence gain and significantly reducing calculation complexity.

The application belongs to the technical field of laser detection, and discloses a laser instantaneous frequency detection device and method, which comprises: a delay self-coherence module, the delay self-coherence module is connected with a laser to be detected, and is used for performing delay self-coherence processing on an output laser signal of the laser to be detected, so as to obtain a to-be-detected laser signal containing an instantaneous phase change of the output laser signal; and a quadrature detection module, the quadrature detection module is connected with the delay self-coherence module, is used for receiving the to-be-detected laser signal, performing quadrature detection on the to-be-detected laser signal, obtaining an instantaneous phase of the output laser signal, and calculating an instantaneous frequency of the output laser signal according to the instantaneous phase. The application can reduce the complexity and cost of a detection system.

This invention discloses a method for identifying dragged interference based on the transmit-receive spatial frequency spectrum, belonging to the field of radar signal processing technology. The invention includes: constructing an FDA-MIMO radar transmitter array and receiver array; calculating the transmitted signal of the transmitter array elements according to a preset frequency increment; receiving the target and interference echo signals of the receiver array, obtaining the target and interference signal vectors within a CPI; calculating the echo covariance matrix based on the target and interference signal vectors, and estimating its Capon spectrum; accumulating the Capon spectrum of multiple coherent processing intervals, then performing peak search to obtain the trajectory of the target and interference, and segmenting the trajectory; calculating the Euclidean distance between peaks within each trajectory, and calculating its variance to identify dragged interference. This invention utilizes the difference in trajectory characteristics between dragged interference and real targets in the transmit-receive spatial frequency spectrum domain of the FDA-MIMO radar, and distinguishes dragged interference from real targets by the magnitude of the trajectory variance without needing to estimate the target velocity.

The invention discloses a multi-static radar physical target and active false target identification method, and belongs to the field of target identification and interference resistance. The method comprises the following steps: estimating deception parameters of a target in a plurality of coherent processing intervals on the basis of measurement information based on a multi-static radar, so as to combine and form a deception parameter vector; according to the characteristic that physical target deception parameters approximately obey zero mean Gaussian distribution, variance is calculated, and a reference vector is constructed; mapping the deception parameter vector and the reference vector to a matrix manifold or a power spectrum manifold; adopting total Bregman divergence and three types of geometric metrics thereof to define a geometric distance; calculating a geometric distance between the target mapping point and the reference point; and comparing the result with a threshold value to realize the discrimination of the physical target and the false target. According to the method, the separability of physical target and false target distribution is enhanced by utilizing information geometric measurement, and the discrimination performance is remarkably improved; the method can achieve excellent performance under the condition of a small number of samples, adapts to real-time countermeasure requirements, and is high in target recognition robustness and controllable in complexity.

The application discloses a dimension reduction processing method for space-time joint forward-looking imaging of an airborne array radar, constructs a forward-looking imaging geometric model of the airborne array radar, receives a three-dimensional echo matrix in range, azimuth and channel, then transforms data in a single coherent processing time interval into a frequency domain and compensates Doppler phase for the echo matrix, then truncates spectral effective information to obtain snapshot data after dimension reduction. Then the newly obtained space-time snapshot is applied to space-time adaptive iterative super-resolution imaging, a space-time super-resolution spectrum curve corresponding to a space-time snapshot of a range-azimuth unit is estimated, and according to a movement speed of an aircraft and antenna scanning parameters, the super-resolution spectrum curve of each range-azimuth unit is subjected to spectrum accumulation, and finally a two-dimensional forward-looking image is obtained. The application effectively compresses space-time data by truncating echo effective information in a Doppler domain, significantly reduces operation complexity, and meanwhile maintains imaging quality.

The application discloses a time-of-flight measurement device, a storage medium and a device. The application obtains a plurality of timestamp sets collected by a TDC in an integration period, then adds the plurality of timestamp sets to obtain a plurality of fragments, performs coherent processing on the fragments to obtain a coherent timestamp set, and generates histogram data according to the coherent timestamp set, so that the count value of the timestamp corresponding to the echo signal in the histogram data remains basically unchanged, the count value of the timestamp corresponding to the noise signal is suppressed, and therefore the signal-to-background noise ratio (SBNR) of a distance detector is improved, and the accuracy of the distance detector in measuring the time of flight is effectively improved.

The invention provides a three-dimensional joint parameter estimation method based on Wi-Fi (Wireless Fidelity) beam forming feedback information (BFI). The three-dimensional joint parameter estimation method based on the Wi-Fi beam forming feedback information (BFI) is characterized in that the three-dimensional joint parameter estimation method based on the Wi-Fi beam forming feedback information (BFI) is provided; the method comprises the following steps: firstly, acquiring BFI of a direct path and a target reflection path between transceivers; secondly, constructing the BFI into a three-dimensional matrix about three dimensions of an antenna, a subcarrier and a data packet, performing smooth decoherence processing on the matrix, and calculating a covariance matrix of the smoothed matrix; secondly, performing characteristic decomposition on the covariance matrix to obtain a signal subspace and a noise subspace; and finally, constructing a spectral function, and obtaining an angle of departure (AOD) between a direct path and a target reflection path, relative time delay and relative Doppler frequency shift through spectral peak search. Based on the three parameters obtained through estimation, the method can be applied to scenes such as positioning or breathing monitoring. According to the method, complete channel state information (CSI) does not need to be accessed, the CSI can be directly extracted from the communication process, and the method has natural robustness for carrier frequency offset and sampling frequency offset, and is easier to realize large-scale popularization and application.

The invention relates to a self-adaptive sunlight-interference-resistant infrared detection method and system, and belongs to the technical field of infrared detection, and the system comprises an infrared transmitting end, an infrared receiving end, a signal preprocessing unit, a band-pass filter unit, a digital phase-locked loop unit and a controller unit. Wherein the controller unit is electrically connected with the infrared transmitting end, the infrared receiving end, the signal preprocessing unit, the band-pass filter unit and the digital phase-locked loop unit, and comprises a dynamic modulation module, a coherent processing module, a coding demodulation module, a feature extraction module, an intelligent decision module and a detection output port. According to the invention, through a cooperative mechanism of dynamic modulation, coherent demodulation and multi-feature verification, it is ensured that only a signal emitted by the system can trigger detection, so that the system can actively adapt to environmental changes and accurately identify a real signal emitted by the system and reflected by a shielded object, and therefore, the detection accuracy is improved in various severe light environments including direct sunlight. Object detection with extremely high reliability and extremely low false alarm rate is realized.

The application discloses a high-resolution range profile feature preserving enhancement method based on iterative weighted sparse decomposition, and comprises the following steps: obtaining radar echo data collected by a radar receiver in a coherent processing time, constructing a two-dimensional radar echo matrix composed of a distance unit number and a pulse sequence array after distance matching filtering; expressing the two-dimensional radar echo matrix as a superposition relationship of a low-rank clutter component matrix and a sparse target component matrix; based on the superposition relationship, constructing an optimization model, and a target function of the optimization model is a sum of a weighted nuclear norm of the low-rank clutter component matrix and an L1 norm of the sparse target component matrix. The method of the application realizes effective suppression of clutter in a strong clutter background by applying adaptive weights to singular values, and meanwhile, key structural features such as the number, position distribution and relative amplitude relationship of scattering points in a target high-resolution range profile are maintained.

The application provides a satellite signal positioning and error correction method, system, positioning terminal and program, and belongs to the communication technical field.The method comprises the following steps: constructing a received signal model of satellite movement; using the received signal model to perform layered processing on the received signal, and using a maximum likelihood method to perform interference source position estimation under long-time observation according to the layered processing result; performing error correction on the interference source position estimation, and completing positioning and error correction on the satellite signal.The application proposes a direct positioning method under long-time observation aiming at the interference source positioning problem under the condition that the adjacent satellite received signal is a weak signal.The method considers satellite movement in the received signal model, and interference source position estimation is obtained by using coherent and non-coherent processing modes.In addition, the application also proposes an error correction algorithm aiming at satellite retransmission frequency error, and the application realizes high-precision positioning of the interference source by using the adjacent satellite weak signal.

This invention relates to radar target detection and tracking technology. To address the limitations of traditional particle filtering over long-term accumulation, it provides a pre-detection tracking method for skywave over-the-horizon radar. This method divides virtual frames and velocity intervals using motion constraints to obtain multiple parallel processing channels, thereby narrowing the coherent pulse number estimation interval and performing coherent processing. Simultaneously, before particle filtering, the constant false alarm rate (CA-CFAR) method ensures that particles are randomly generated only in range-Doppler cells exceeding a threshold, further reducing the particle number. This invention reduces computational load while improving the detection and tracking capabilities of OTH radar for weak targets. This invention combines echo data preprocessing with coherent and non-coherent processing techniques, improving the detection and tracking performance of weak targets in skywave over-the-horizon radar while reducing computational complexity through multi-channel and low-threshold methods.

This invention relates to an adaptive anti-sunlight interference infrared detection method and system, belonging to the field of infrared detection technology. The system includes: an infrared transmitter, an infrared receiver, a signal preprocessing unit, a bandpass filter unit, a digital phase-locked loop unit, and a controller unit. The controller unit is electrically connected to the infrared transmitter, infrared receiver, signal preprocessing unit, bandpass filter unit, and digital phase-locked loop unit, and includes: a dynamic modulation module, a coherent processing module, an encoding and demodulation module, a feature extraction module, an intelligent decision-making module, and a detection output port. This invention, through a collaborative mechanism of dynamic modulation, coherent demodulation, and multi-feature verification, ensures that only signals emitted by the system itself can trigger detection. This allows the system to proactively adapt to environmental changes and accurately identify the true signals emitted by the system and reflected by obstructed objects. Thus, it achieves extremely high reliability and extremely low false alarm rate object detection in various harsh light environments, including direct sunlight.

The invention discloses a distance measurement method based on frequency domain super-resolution and path geometric constraint and related equipment, and relates to the field of distance measurement. The method comprises the following steps: receiving a broadband detection signal sent by a sending end to obtain a received signal; performing frequency domain coherent processing on the received signal and a pre-stored broadband detection signal copy to obtain channel frequency response data; according to the calculated signal-to-noise ratio of each frequency point in the channel frequency response data, filtering the frequency points with the signal-to-noise ratio lower than a preset signal-to-noise ratio threshold to obtain effective channel frequency response data; based on the effective channel frequency response data, adopting a preset time delay algorithm to calculate direct signal propagation time delay of the direct path; and calculating a physical distance based on the direct signal propagation time delay and a calculation rule corresponding to a preset distance measurement mode. By implementing the above technical scheme, the accuracy of distance measurement in a multipath signal propagation scene is improved.

The invention discloses a faint target detection method and device and a medium, and relates to the technical field of radar signal processing and time frequency control. The method comprises the following steps: implementing a time-frequency discipline on a near-end reference through an atomic clock, and establishing a phase-stable reference across a coherent processing interval; echo signals are collected in a segmented mode according to coherent processing intervals, range walk correction and phase compensation are carried out on echoes of all segments according to the motion state of the platform, and coherent accumulation in the segments is achieved; calculating a phase continuity quality factor; based on the phase continuity quality factor, performing adaptive selection between coherent splicing and semi-coherent power superposition to obtain a cross-segment synthesis result; and performing likelihood fusion and constant false alarm detection on the cross-segment synthesis result in a statistical layer, and outputting a target existence judgment and parameter estimation result. According to the invention, a high coherence retention rate can be maintained and a false alarm can be stably controlled in the presence of platform maneuvering and environmental disturbance, so that the first detection probability and the continuous tracking capability of a long-distance low observable target are improved.

The invention relates to the field of signal processing, in particular to a radar target tracking and recognition method based on multi-dimensional information fusion, which comprises the following steps: performing pulse compression and coherent processing on a sea surface echo signal received by a radar, constructing a distance-Doppler graph, and detecting and positioning a suspected target through a constant false alarm rate. And the radial speed characteristic and the distance dimension contour fitting coefficient based on the weighted least square method are synchronously calculated. Afterwards, the motion and structure features are fused with a traditional energy state, an extended target state with a unique identification tag is constructed, and a probability distribution model of an initial multi-target state is established by adopting a tag multi-Bernoulli random finite set theory; and performing multi-target state estimation under a Bayesian recursion framework by using a generalized label multi-Bernoulli filter. Time domain statistical features are extracted based on a tracking trajectory, a vector machine is adopted to discriminate a target type, and through multi-dimensional information fusion and joint optimization processing, tracking stability and recognition reliability of a marine weak target are improved.

The application relates to the technical field of medical equipment, and discloses an ultrasonic imaging method and ultrasonic equipment. The method comprises the following steps: acquiring a plurality of groups of ultrasonic echo beams generated by ultrasonic emission of an ultrasonic probe each time for a target part; dividing the plurality of groups of ultrasonic echo beams according to a preset grouping mode to obtain a first echo beam set and a second echo beam set; performing non-coherent compound processing on the first echo beam set to obtain a non-coherent processing result, and performing coherent compound processing on the second echo beam set to obtain a coherent processing result; fusing the non-coherent processing result and the coherent processing result to obtain a target echo beam; and performing imaging processing on the target echo beam to generate a target ultrasonic image. Through implementation of the technical scheme, image errors caused by phase problems near a transmission focal zone can be reduced to the maximum extent, and the accuracy of focused imaging is ensured.

This application provides a method, communication device, and system for information transmission, relating to the field of sensing technology. In this method, the device can classify data based on the scattering characteristic information obtained by sensing a target at a corresponding measurement angle. For example, it can distinguish between data that satisfy a coherent relationship and data that satisfy an incoherent relationship from at least two sets of data obtained by sensing a target. Furthermore, it performs coherent processing on the data that satisfies the coherent relationship and incoherent processing on the data that satisfies the incoherent relationship. Thus, this application can support appropriate processing of data acquired in large-aperture observation scenarios.

The invention provides an anti-folding clutter method based on stagger MTI. The anti-folding clutter method comprises the steps of S100, establishing a slow time total echo model of a frequency modulation agile airborne radar in a clutter environment; step S200, performing grouping stagger MTI and coherent processing on the echo signals; and step S300, folded clutter elimination processing is carried out, and the distance-Doppler spectrum is output, and far-region folded clutter is suppressed by carrying out orthogonalization design on pulses of front and back repetition periods and utilizing a method of alternating positive and negative slopes of inter-pulse waveforms and repetition frequency stagger design, so that the suppression characteristics of the positive and negative slope frequency modulation pulses on the folded clutter are effectively utilized, and the suppression effect of the distance-Doppler spectrum on the folded clutter is improved. And the influence of folding clutter is remarkably reduced while the target detection performance is maintained.

The application provides a radar coherent processing method and system for pulse group frequency repetition period joint agility, comprising the following steps of designing pulse group frequency and repetition period; generating a radar signal; performing two-pulse group MTI processing; performing MTD coherent processing and CFAR detection. The same frequency is used in the pulse group to be compatible with the MTI cancellation of static clutter, and the speed-frequency coupling phase term and the distance-frequency coupling phase term can be compensated by the frequency-pulse repetition period joint agility strategy between pulse groups, so that coherent accumulation is realized.

The application discloses a clutter-avoiding airborne radar target detection method, system, device and medium. The detection method comprises the following steps: collecting echo signals; grouping the echo signals according to a pulse repetition frequency to obtain a pulse repetition frequency signal group; performing Keystone transformation and Doppler ambiguity number compensation processing on all pulse repetition frequency signal groups, performing discrete Fourier transform at a slow-time sampling moment, performing first-layer detection threshold detection on a range-Doppler result, performing demodulation and coherent processing to obtain a coherent result; performing second-layer detection threshold detection on the coherent result, and performing target judgment and parameter estimation to obtain accurate range information of the target and speed information of the target. The detection method can effectively avoid the influence of clutter on the target and realize two-dimensional demodulation processing of the range-Doppler of the target, thereby effectively improving the detection accuracy of the target. The application can be widely applied to the technical field of radar detection.

The invention discloses a forward and backward scattering integrated microwave photon radar system, and the system comprises a light source module which is used for generating an optical carrier signal; the signal generation module is used for generating a chirp signal based on the optical carrier signal and modulating the chirp signal to the optical carrier to form an optical sideband signal; the photoelectric conversion module is used for converting the optical sideband signal into a microwave signal; the transmitting antenna is used for transmitting the microwave signal to irradiate a target in a detection area; and the receiving antenna is used for receiving the microwave signals scattered back by the target, and the scattered signals comprise forward scattered signals and / or backward scattered signals. According to the invention, high-coherence processing and fusion of forward and backward scattering signals are realized on the same optical domain platform through a microwave photon technology, so that high-sensitivity detection of a small-radar-sectional-area target and accurate distance resolution of the target can be obtained at the same time.

The invention discloses a super-resolution multipath time delay estimation method for Fourier precoding OCDM signals in a dynamic scene, and the method comprises the steps: carrying out the Fourier precoding of a pilot symbol, generating a precoding orthogonal linear frequency modulation wavelength division multiplexing signal through modulation, and eliminating the coupling effect between the time delay and Doppler frequency shift in a time-frequency double-selection channel; doppler frequency shifts of different paths are directly estimated according to the position offset of the received pilot signals in the Fresnel domain, and the number of the multiple paths is determined; and calculating a covariance matrix of the received signal, carrying out decoherence processing, carrying out subspace decomposition on the covariance matrix by using a multiple signal classification algorithm to obtain a spatial spectrum, and determining a multipath time delay estimation value according to a spectrum peak position of the spatial spectrum. The method is suitable for underwater acoustic mobile communication and environment perception with Doppler frequency shift, the relative root-mean-square error of time delay estimation can be remarkably reduced in a high-speed state, and a reliable solution is provided for super-resolution time delay estimation in a dynamic scene.

This invention relates to a multi-mode radar composite detection method, belonging to the field of microwave-laser composite detection technology, and solves the problems of inability to achieve all-weather detection, low detection accuracy, and weak adaptability. The method includes: splitting a laser generated by a laser into multiple paths; modulating the first laser path to generate a microwave radar transmission signal and receiving the microwave radar echo signal; modulating the second laser path to generate an intermediate frequency (IF) echo signal; generating a single-photon laser pulse based on the third laser path and receiving the single-photon laser pulse echo signal; generating a laser transmission signal based on the fourth laser path, transmitting the laser transmission signal towards the target and receiving the laser echo signal; using the laser echo signal to coherently process the fifth laser path to obtain a coherent IF signal; and processing the IF echo signal, the laser pulse electrical signal, and the coherent IF signal respectively to obtain target characteristic parameters.

The application discloses a kind of high-speed motion platform front view three-dimensional super-resolution imaging methods, first derivation moving target and the distance history of platform, accurately describe the front view Doppler phase change caused by high-speed relative motion, then adopt random sparse azimuth-elevation two-dimensional scanning strategy, reduce target coherent processing time, ensure the secondary approximation accuracy of distance history under high-speed motion, then based on sparse scanning matrix and Doppler phase matrix, construct sparse Doppler convolution model to obtain echo accurate representation under high-speed platform, finally through iterative noise variance estimation, utilize weighted least square criterion derivation adaptive iterative estimation method, obtain front view super-resolution imaging result.The method of the application solves the problem of front view azimuth-elevation super-resolution performance decline caused by high-speed motion, compared with prior art, can realize front view three-dimensional super-resolution imaging under high-speed condition, while effectively reducing echo dimension, improve front view three-dimensional super-resolution imaging algorithm efficiency.