14 results about "Channel complex" patented technology

The invention provides an SAR target screening method based on binary super-dimensional calculation, and relates to the technical field of real-time target detection. The method comprises the following steps: directly carrying out real and virtual part solution and sign function quantization on I / Q dual-channel complex data of an original echo of a synthetic aperture radar (SAR) to obtain a binary fusion matrix; constructing an abnormal profile based on a preset background statistical model, and adaptively dividing the quantized data into multiple segments according to the abnormal profile; performing super-dimensional mapping on each segment through an independent random binary projection matrix, generating segmented super-vectors, and splicing the segmented super-vectors into a complete sample super-vector; and finally, target discrimination is realized by calculating the Hamming distance between the target and a pre-stored background / target prototype super vector. The quantization logic can be dynamically switched according to the target size, and the problem that a single quantization strategy is poor in adaptability is effectively solved. And through an adaptive segmentation mechanism of energy perception, the weak target characterization capability is effectively enhanced, and the screening accuracy under a strong clutter background is improved.

The invention provides a radar rainfall measurement method and device based on an oblique 45-degree depolarization ratio, and the method comprises the steps: collecting single-transmitting double-receiving two-channel complex voltage data through employing a radar which achieves the oblique 45-degree polarization through the reconstruction, and calculating an oblique linear depolarization ratio and a reflectivity factor Z; a melting layer is observed and recognized according to a vertical pointing section collected by the radar in a vertical pointing mode, and the upper boundary and the lower boundary of the melting layer are applied to a nearly horizontal scanning mode to achieve liquid rainfall recognition; and carrying out rain attenuation correction on the sum Z, and according to the sum Z after the rain attenuation correction, inverting rainfall parameters such as rainfall intensity, mass weighted average diameter, normalized intercept, number concentration, water content and the like through a lookup table or a neural network. According to the invention, the precision and robustness of rainfall measurement are improved.

The invention discloses a vertical measurement ionogram O / X wave separation method based on polarization matched filtering, and the method comprises the steps: obtaining a dual-channel complex signal, and carrying out the incoherent accumulation to obtain echo intensity; using an OS-CFAR detector and morphological processing to generate a mask; calculating a phase difference based on the mask, and fitting through a double-Gaussian mixture model to obtain O-wave and X-wave characteristic phases; estimating a complex polarization ratio; constructing a polarization matched filter weight vector, multiplying the polarization matched filter weight vector with the dual-channel signal, and separating to obtain an O / X wave complex signal matrix; a separated ionogram is generated through amplitude calculation and detection. The method does not depend on circular polarization hypothesis, actual polarization parameters can be directly estimated, high-precision separation is achieved through polarization matched filtering, and robustness and accuracy are improved.

The invention discloses a phase noise measurement method and system based on vector network analyzer hardware, and relates to the technical field of communication measurement instruments and meters, and the method comprises the steps: receiving dual-channel ADC data, preprocessing the dual-channel ADC data to obtain preprocessed baseband complex IQ data, carrying out the phase analysis of the preprocessed baseband complex IQ data to obtain phase data, and calculating the phase noise of the baseband complex IQ data according to the phase data. Performing cross-correlation operation and amplitude analysis on the phase data to obtain phase noise data; carrying out amplitude analysis on the preprocessed baseband complex IQ data to obtain amplitude data, carrying out dual-channel complex cumulative average operation on the amplitude data to obtain amplitude modulation noise data, and processing to obtain a phase noise spectrum result and an amplitude modulation noise spectrum result; and performing peak detection and stray judgment on the phase noise spectrum result and the amplitude modulation noise spectrum result to obtain a stray identification result, and performing stray elimination on the stray identification result to obtain a final phase noise measurement value and an amplitude modulation noise measurement value.

The invention provides an antenna test method and system for a 4D millimeter wave radar, and the method comprises the steps: generating a simulation target with a preset distance and a preset non-zero speed through a radar echo simulator, collecting the point cloud data of a to-be-tested radar at a plurality of rotation angles, and carrying out the screening of the data in two dimensions, namely the distance and the speed, so as to achieve the test of the antenna of the to-be-tested radar. The simulation target point is accurately identified from static environment clutters, complex frequency spectrum data of each channel corresponding to the target point are extracted, and the gain and phase characteristics of the antenna are determined according to the change of the complex frequency spectrum data along with the rotation angle. A traditional microwave darkroom is not needed, environmental clutter interference is effectively restrained through a signal processing means, and therefore the cost and the space requirement of a calibration system are remarkably reduced, portability and test flexibility are improved, and meanwhile the accuracy of a calibration result is guaranteed.

The invention discloses a channel estimation method for an orthogonal time-frequency space modulation system. Aiming at the time-varying channel estimation problem in high dynamic scenes such as satellite communication and the like, the method comprises the following steps: firstly, inserting a single pilot symbol into a time delay-Doppler grid of a system transmission signal, and setting a protection symbol area; at a receiving end, traversing pilot frequency receiving signals according to time delay coordinates, detecting effective paths by setting a threshold value, performing correlation operation by using a Doppler domain basis function, and preliminarily estimating Doppler frequency offset and channel complex gain of each path; and gradually optimizing multi-path parameter estimation by adopting an iterative fitting mode and calculating and updating residual pilot response until a stopping criterion is met. According to the method, the calculation complexity is remarkably reduced while the estimation precision similar to that of a traditional method is kept, the method is particularly suitable for a multi-path sparse channel with fractional Doppler, and an efficient and reliable channel estimation solution is provided for an OTFS communication system with limited resources.

The invention relates to a multi-channel voice signal noise reduction method and device. The method comprises the following steps: acquiring a multi-channel vibration signal and a pure noise signal acquired by a distributed optical fiber acoustic sensing system; performing framing processing on the multi-channel vibration signal to obtain a frequency domain complex spectrum of each frame of each channel; determining a spectral entropy and a low-frequency signal-to-noise ratio according to the pure noise signal, and performing adaptive adjustment on an over-reduction coefficient according to the spectral entropy and the low-frequency signal-to-noise ratio to obtain a target over-reduction coefficient; performing spectral subtraction operation on the first amplitude spectrum according to a target over-reduction coefficient, and performing phase correction on the first phase spectrum based on the time delay of each channel to obtain a single-channel complex spectrum of each frame, thereby effectively suppressing non-stationary noise interference and keeping signal phase consistency through self-adaptive adjustment of the over-reduction coefficient and combination of multi-channel phase correction; and performing phase optimization and superposition reduction on the single-channel complex spectrum to obtain a time domain signal after noise reduction and reconstruction, thereby improving the feature fidelity of the vibration signal through phase optimization and superposition reduction.

The application provides an AGV communication channel modeling method and system based on an ellipsoid geometry random model, and belongs to the technical field of wireless communication channel modeling; the method comprises the following steps: a three-dimensional digital scene covering multiple frequency bands, AGV speeds and container densities is constructed, and a multi-dimensional channel data set is constructed based on ray tracing; a dynamic ellipsoid geometry model with a fixed base station and an AGV as the focus is constructed, and a time-varying characteristic is introduced by updating the AGV position in real time; the communication channel is divided into three parts, namely, a line-of-sight part, a ground reflection part and a non-line-of-sight part, the channel complex gains of the three parts are respectively modeled, and are superimposed to synthesize the channel impulse response under the FR3 frequency band. Through the introduction of the speed-dependent Doppler effect and the density-dependent metal scattering mechanism, the time-varying non-stationary characteristics of the AGV channel in the metal dense scene of the port can be accurately described, and efficient and accurate theoretical model support is provided for the intelligent port AGV communication design.

This invention discloses a DOA estimation method based on a dual-channel complex convolutional neural network. The method first formulates the DOA estimation problem as a multi-label classification task, using the complex covariance matrix of the array received signal as input. This input is fed into the first channel, composed of standard convolutional layers, and the second channel, composed of dilated convolutional layers and pooling layers. The dilated convolutional layers increase the receptive field of the feature map without losing angular information. The features extracted from the two channels are fused and then output through a fully connected layer and a sigmoid function to achieve angular classification results, thus realizing DOA estimation under multi-source input. This invention further improves the accuracy of DOA estimation. Simulation results show that the dual-channel complex neural network feature fusion method has a better convergence speed, and under conditions of low signal-to-noise ratio and few snapshots, this method has higher estimation accuracy.

This invention discloses a decoupling whitening fast convergence method suitable for active road noise control systems. The steps include: (1) hardware configuration in an ARNC system based on a feedforward strategy; (2) decomposing the secondary path into a minimum-phase part and an all-pass part based on internal and external integral solutions, then filtering the output of the control filter through the minimum-phase part and filtering the error signal through the all-pass part; (3) decomposing the spectral density matrix of the reference signal to obtain the spectral factor function; (4) using the filtered error signal and the whitened reference signal, combined with the minimum mean square algorithm for frequency domain filtering error, updating the control filter, and outputting the control signal to drive the cancelling speaker to emit sound, which propagates through the secondary path and coherently superimposes with the road noise signal near the ear. This invention can be used in ARNC systems in multi-channel complex scenarios, accelerating the convergence speed of the FeLMS algorithm through secondary path decoupling and reference signal whitening operations.

This invention relates to the field of physical layer secure communication technology, and provides a method and apparatus for synchronously generating group keys and paired keys. The method includes: a central node acquiring the azimuth angles and corresponding channel complex gains of each edge node, designing the switching array parameters of a time modulation array based on the azimuth angles of each edge node, calculating the average radiation pattern coefficients of all edge nodes, and transmitting them collectively; the central node generating a group key and modulating it into a modulated signal using the time modulation array and transmitting it; the central node generating corresponding paired keys for each edge node and encrypting them to obtain paired key ciphertext, which is then sent to the corresponding edge node; each edge node receiving the modulated signal performs coherent demodulation to obtain demodulated symbols, performs hard decision on the demodulated symbols, and obtains the group key; each edge node decrypts the paired key ciphertext using the average radiation pattern coefficients and the demodulated symbols to obtain the paired key.

The invention provides an antenna rotating speed control method and system and a readable storage medium, and relates to the technical field of radar system control, and the method comprises the steps: receiving a radar echo signal, carrying out the pulse compression processing, and obtaining a difference channel complex signal and a sum channel complex signal; calculating an echo ratio amplitude value based on the difference channel complex signal and the sum channel complex signal, and multiplying the echo ratio amplitude value by a scaling coefficient to obtain a scaling ratio amplitude value; obtaining a current frame antenna rotating speed instruction according to the arc tangent value of the scaling ratio amplitude value and the maximum rotating speed of the antenna; determining antenna steering according to the ratio phase of the difference channel complex signal to the sum channel complex signal; wherein the rotating speed and the rotating direction of the antenna are independently calculated according to each frame of data, and continuous tracking of the target is achieved. The system comprises an echo receiving module, a pulse compression module, an arc tangent control module, a steering judgment module and a driving module. According to the invention, when the radar tracks the target, the rotating speed and the rotating direction of the antenna are controlled, the overshoot and lag probability is effectively reduced, and the target loss probability is further reduced.

The invention relates to the technical field of industrial equipment fault diagnosis, and discloses a paper machine fault diagnosis method based on multichannel grouping, which comprises the following steps: firstly, preprocessing and re-sampling signals of different physical types, and grouping according to a vibration group, a pressure and current group and a temperature group; inputting each group of time sequence windows into a multi-scale time-frequency dynamic attention module to extract time-frequency attention features, obtaining gently changed time sequence representation through slow feature layer constraint, reconstructing by an intra-group long and short term memory auto-encoder, and calculating a time sequence point reconstruction error and a window aggregation error; and finally, completing fault judgment by combining the static threshold value and a self-adaptive dynamic threshold value based on normal window sliding statistics. The method realizes high-precision modeling and adaptive anomaly detection of multi-channel complex time sequence signals, has the advantages of high diagnosis precision, low false alarm rate, small detection delay and the like, and is suitable for online monitoring and intelligent operation and maintenance of the paper machine.

The application relates to the technical field of semiconductor testing and noise characterization, and discloses a low-error semiconductor low-frequency noise voltage spectral density measurement method, which comprises the following steps: establishing a static working point of a measured semiconductor device through a bias supply unit, generating a pseudo-random pilot signal through a pilot injection unit and injecting the pilot signal into an input end as a path characterization reference, capturing a mixed signal after superposition of essential noise and the pilot through a double-channel amplification unit in parallel, synchronously acquiring digital sequences of each channel, performing cross-power spectrum estimation on the sequences and an original pilot reference sequence through a digital processing unit, extracting an instantaneous transfer function reflecting channel complex gain characteristics, performing real-time drift compensation according to the instantaneous transfer function and constructing an environmental coherence factor, stripping environmental correlation noise from compensated data by using the factor, and deducting a pilot self-energy item in combination with the instantaneous transfer function. The application eliminates the influence of system drift and environmental interference, and improves the accuracy of low-frequency noise characterization.