1049 results about "Frequency offset" patented technology

A wireless transmit / receive unit (WTRU) may receive subband non-overlapping full duplex (SBFD) configuration information. The SBFD configuration information may be associated with subbands for uplink transmission and subbands for downlink reception. The WTRU may receive scheduling information associated with physical uplink shared channel (PUSCH) transmissions. The scheduling information may comprise a first frequency domain resource allocation (FDRA). The WTRU may transmit a first PUSCH transmission using a first frequency resource. The WTRU may determine that at least a second PUSCH transmission is to be sent using at least one OFDM symbol. The WTRU may determine that the first frequency resource overlaps. The WTRU may receive one or more of a second FDRA or a frequency offset for the second PUSCH transmission. The WTRU may determine a second frequency resource for transmitting the second PUSCH transmission. The WTRU may transmit the second PUSCH transmission using the second frequency resource.

The invention relates to the technical field of wireless charging, and provides a foreign matter detection method and system for a wireless charging system and a storage medium. The method comprises the following steps: firstly, calibrating at multiple temperature points and establishing a temperature-parameter comparison table under the condition of no foreign matters; in a no-load standby state, the inversion module sends out detection drive and collects voltage, current and temperature; calculating a real-time quality factor and resonant frequency according to sampling, obtaining a compensation reference according to a temperature look-up table, and solving the variation of the quality factor and the resonant frequency; and performing fusion judgment by adopting dual-condition locking or weighted scoring, and triggering fault protection when a foreign matter is confirmed. Due to the fact that equivalent inductance and resistance changes are caused by metal foreign matters, quality factors are remarkably reduced along with resonant frequency deviation, temperature excursion and foreign matter effects are distinguished through temperature compensation, and dual-condition locking or weighted scoring fusion judgment is combined, the interference immunity and accuracy of detection are improved, false alarms and missing alarms are remarkably reduced, and the detection accuracy is improved. The method is suitable for high-power wireless charging scenes.

The invention relates to the technical field of ecological system service function evaluation. The invention relates to a frequency offset correction algorithm in HPLC (High Performance Liquid Chromatography) + HRF (High Radio Frequency) dual-mode communication. The method comprises the following steps: S1, collecting phase sequence data from an HPLC communication link, collecting frequency offset estimation data and corresponding confidence data from an HRF communication link, and adaptively adjusting a preset detection threshold value of the phase sequence data according to the confidence data; s2, performing pulse abnormal sample point detection and elimination on the phase sequence data according to the adjusted preset detection threshold value; according to the method, the detection threshold is dynamically adjusted through the confidence data, so that the anomaly detection process can be matched with the current interference environment in real time, the integrity of the phase sequence data is maintained, and the problem of insufficient adaptability of a fixed detection threshold in an electromagnetic interference dynamic change scene is solved; and a more reliable phase data basis is provided for subsequent interpolation compensation and frequency offset estimation, so that the frequency offset correction precision of the dual-mode communication system is improved.

The embodiment of the invention provides a time-space synchronization method and device, electronic equipment and a medium, which are used for solving the problem of inaccuracy of a local clock in related technologies. In the embodiment of the invention, the electronic equipment combines the average deviation pseudo-range, the RTT jitter and the target frequency offset into the multi-dimensional observation vector, so that the error source of clock synchronization is fully covered. The time deviation and the frequency deviation of the clock are accurately and effectively determined through a Kalman filtering algorithm, recursive processing of observation vectors and dynamic estimation of the time deviation and the frequency deviation of the clock, and high-precision synchronization of the local clock in a complex environment is achieved in combination with the optimization capability of the Kalman filtering algorithm. And the time of the local clock is the time determined according to the time of the multiple clocks, so that the clocks are more accurate.

The invention discloses a wind turbine generator blade damage judgment method and detection system based on voiceprint detection, and belongs to the technical field of wind turbine generator blade detection. The damage judgment method comprises the following steps: acquiring environmental parameters of a wind power plant, and establishing a sound velocity correction model based on the environmental parameters; acquiring a blade resonance sound signal, and correcting the blade resonance sound signal based on the sound velocity correction model to obtain a blade resonance sound signal with a high signal-to-noise ratio; performing FFT spectrum analysis on the blade resonance sound signal with the high signal-to-noise ratio, identifying the peak position of the first three-order natural resonance frequency of the blade, and performing analysis to obtain the current modal frequency, damping ratio and sub-band energy distribution entropy value of the blade; historical baselines of the modal frequency, the damping ratio and the sub-band energy distribution entropy of the blade in the healthy state are obtained, and the modal frequency offset, the damping ratio change rate and the acoustic impedance spectrum entropy of the blade are obtained; and wind turbine generator blade damage determination is carried out by using a high-precision time difference detection technology.

The invention discloses a construction method and a modulation method of a three-port multi-frequency MMC topology based on bridge arm multiplexing, and relates to the technical field of power electronics. The construction method comprises the steps that sub-modules of a traditional double-bridge-arm MMC are integrated and optimized into a three-bridge-arm structure through a current conversion branch, independent energy interaction of three ports is achieved through an auxiliary bridge arm, multi-frequency operation modes of power frequency, frequency division, direct current and the like are supported at the same time, and therefore the utilization rate of the bridge arm sub-modules is increased, and the energy utilization rate of the MMC is increased. And the overall size and the manufacturing cost of the converter are reduced. Based on three-port multi-frequency coordination control and power balance requirements, a modulation method of the topological structure is provided, a multi-frequency coordination modulation strategy is adopted, frequency offset is performed through an auxiliary bridge arm to reduce cross interference of port frequency, and output waveform quality is improved through multi-objective optimized capacitor voltage balance control. And meanwhile, direct-current side faults are effectively eliminated by means of the auxiliary bridge arm.

The embodiment of the invention provides a downlink signal sending method and a downlink signal processing method, which are characterized in that a downlink signal is obtained on the satellite side based on a supplementary synchronization sequence, and then time-frequency synchronization is carried out on the terminal equipment side by using the downlink signal from the satellite. In the application, the terminal device can realize time-frequency offset tracking compensation without acquiring satellite ephemeris information and using GNSS (Global Navigation Satellite System) equipment, so that the influence of ephemeris errors and GNSS errors on time-frequency synchronization performance after the terminal device is shut down for a long time is eliminated, and the problem that the time-frequency synchronization performance of the terminal device is influenced in the related technology is solved. The problem of low precision of time-frequency offset tracking compensation in the satellite-ground communication process is solved, and the time-frequency synchronization success rate of satellite-ground communication under the conditions of inaccurate ephemeris and high speed is improved.

The invention relates to the technical field of data compression, in particular to a ZSTD compression algorithm optimization method based on joint coding and ternary decomposition, and the method comprises the following steps: S1, building a joint frequency table based on the joint distribution of the literal length and the matching length of a previous section, setting a frequency deviation criterion, and dynamically adjusting a low-frequency combination proportion; s2, decomposing the offset value structure into a leading segment, a trailing segment and a middle segment, performing bit width-entropy ratio analysis on the middle segment, and selecting a symbol index or bit stream coding; and S3, entropy discriminant coding is performed on the joint symbol and the offset symbol respectively, and a structure position is mapped synchronously to generate a structured compressed output stream. According to the method, collaborative optimization of frequency self-adaption, redundancy minimization and structured mapping is realized through joint symbol dynamic modeling and offset ternary structure entropy discriminant coding, so that the ZSTD compression efficiency and the coding stability are remarkably improved.

The invention provides a multi-antenna MIMO architecture synchronization method and device, a program product and a storage medium, and relates to the technical field of wireless communication. Receiving sampling signals through a plurality of receiving channels; performing down-sampling on each sampling signal to obtain a down-sampling signal; determining a plurality of cache regions to store each downsampling signal, and performing cross-correlation operation on each downsampling signal and a local synchronous time domain signal; when any receiving channel detects an effective peak value, determining the position of the effective peak value as a preliminary synchronization position; determining a corresponding search window range, and performing weighted stacking on the target cross-correlation results to obtain an overall correlation peak value; searching a maximum value in all the total correlation peak values, and determining a position corresponding to the maximum value as a final synchronization position; and calculating a frequency offset estimation value of each receiving channel according to each pilot signal, and carrying out weighted average on each frequency offset estimation value to obtain a final frequency offset estimation value. By adopting the method, the wireless frame synchronization precision can be improved.

The invention belongs to the technical field of signal processing, and particularly relates to a coherent light high-speed transmission signal processing method based on deep joint compensation, which comprises the following steps of: performing fine frequency offset and inter-carrier interference joint preprocessing on a coherent light receiving sampling sequence; obtaining a pre-processing output sequence and at least one estimation parameter derived from fine frequency offset and inter-carrier interference combined pre-processing; inputting the preprocessing output sequence into a diffusion type score guide joint compensation network module to obtain a deep joint compensation sequence; performing online judgment and decoding on the deep joint compensation sequence, and adaptively updating internal parameters of the diffusion type score guide joint compensation network module when a preset adaptive updating condition is met; according to the invention, the symbol residual error can be obviously reduced, the forward error correction gain can be improved, and the stability and robustness of the system under high-order modulation, high symbol rate and long-distance link scenes can be enhanced.

The invention relates to the technical field of signal reconstruction, in particular to a complex electromagnetic environment-oriented millimeter wave signal blind source separation and reconstruction system, which comprises a frequency spectrum trend division module, a path fading construction module, an initial cluster label generation module, a multi-solution path screening module and a fusion reconstruction execution module. According to the method, power spectral density sequence processing is carried out on millimeter wave frequency domain data, a multi-dimensional feature group is formed according to a path loss factor, an angle of arrival and the like, and an initial feature cluster is screened through an Euclidean distance, so that the accuracy of signal source classification is effectively improved; after the frequency domain response and the phase contour are continuously subjected to point comparison, path screening is completed by integrating a mean square error residual value, the path misjudgment probability is reduced, time domain resampling and phase frequency offset standardization are executed in fusion reconstruction, the consistency and fidelity of signal reconstruction are enhanced, and the reconstruction precision is improved. The whole process improves the separation accuracy and reconstruction precision of mixed signals in a complex electromagnetic environment.

The invention relates to a low-orbit satellite short burst signal high-precision capturing method and device, equipment and a medium. The method comprises the following steps: sequentially carrying out digital down-conversion and L-time signal pseudo code rate down-sampling on a low earth orbit satellite short burst signal sequence sampled by an ADC (Analog to Digital Converter) to obtain a down-sampled signal sequence; performing pre-accumulation processing on the down-sampling signals of every adjacent L points in the down-sampling signal sequence, and performing coarse capture on the pre-accumulated signal sequence by adopting a PMF-FFT algorithm to obtain a coarse pseudo code phase and a coarse frequency offset value; and performing serial code phase search on the down-sampling signal sequence based on the coarse pseudo code phase and the coarse frequency offset value, optimizing to obtain a fine pseudo code phase, and optimizing the estimation precision of the coarse frequency offset value according to the fine pseudo code phase and a frequency offset estimation algorithm based on a phase relation to obtain a fine frequency offset value. By adopting the method, the acquisition precision and speed of the short burst signal of the low-orbit satellite can be improved.

The invention provides a distributed coherent communication system synchronization method, and the distributed coherent communication system enables dispersed nodes in a space to cooperate with each other through the construction of a virtual antenna array, so as to form a directional wave beam, thereby achieving the control and enhancement of a signal direction. A distributed Kalman filtering framework is introduced, a frequency and phase joint state space model is constructed, local observation data of nodes and neighbor state information are optimally fused, and dynamic estimation and compensation of frequency offset and phase errors are achieved. An updating strategy is designed in combination with an event triggering mechanism, local Kalman filtering prediction is executed in conventional iteration to suppress random noise and control the communication burden and calculation complexity of a system, meanwhile, the standard deviation of a residual phase error is effectively reduced by one order of magnitude, and the synchronization performance is improved.

The invention discloses a carrier tracking method suitable for a multi-bit spread spectrum signal, and relates to the technical field of multi-bit spread spectrum, the carrier tracking method comprises the steps of coarse frequency offset correction, multi-bit spread spectrum, average phase estimation and delay phase correction.The carrier tracking method comprises the steps that firstly, a sliding DFT algorithm is adopted to estimate frequency offset, and a coarse frequency offset available correction signal is obtained; secondly, adaptively selecting the number of available windows according to historical data corresponding to the current signal-to-noise ratio; the method comprises the following steps: firstly obtaining a window intermediate point spread spectrum period, then extracting a carrier phase estimation value of the window intermediate point spread spectrum period, finally delaying a correlation value by the spread spectrum period to realize time sequence alignment and eliminate phase deviation, and finally obtaining information bits corresponding to each spread spectrum period by extracting and correcting a real part of the correlation value, matching a local sequence number and mapping. According to the method, the phase estimation precision under the low signal-to-noise ratio can be improved, parameter self-adaption to high and low dynamic scenes of a satellite is realized, the coherent judgment performance is improved, and the hardware complexity is reduced.

Disclosed are an auxiliary pilot adaptive optimization method, apparatus and device, and a medium, which relate to the technical field of wireless communications, and solve the problems of static configuration, resource waste and single function of the existing auxiliary pilot. An auxiliary pilot frequency sequence is designed into a synchronous prefix and an estimation core section, and the synchronous prefix adopts a pseudo-random sequence with high autocorrelation and is used for timing synchronization (positioning through a sequence autocorrelation peak value) and frequency synchronization (calculating frequency offset through a phase difference) in a demodulation process; the estimation core section adopts an orthogonal sequence with a low peak-to-average ratio and is used for accurate channel estimation; the double-segment sequence is connected through a preset code pattern, and it is ensured that a demodulation end can perform synchronous analysis. By sensing the channel state in real time, parameters of the auxiliary pilot frequency are dynamically adjusted, and a synchronization function is fused, so that the demodulation performance and the resource utilization rate are improved.

The invention provides a low earth orbit satellite communication initial time frequency offset estimation method, and belongs to the technical field of satellite communication. When satellite communication initial time-frequency offset estimation is carried out, initial time-frequency offset coarse estimation is firstly completed based on a first auxiliary synchronization signal, time-frequency offset coarse compensation is carried out on a received signal by using an estimation result, then initial time-frequency offset fine estimation is further completed based on a second synchronization signal, and the compensated signal is sent to a demodulation module for demodulation. The two-step time-frequency offset estimation method provided by the invention combines the advantages of the symmetric Chirp reference signal and the pseudo code sequence for time-frequency offset estimation, can realize rapid and accurate time-frequency offset estimation in a large-frequency offset scene, and improves the performance of a low-orbit satellite communication system.

The invention discloses a village island micro-grid virtual synchronous machine parameter optimization and cooperative control method oriented to frequency support, and relates to the technical field of electrical automation, and the method comprises the steps: obtaining village power distribution network parameters and load side parameters, and basic technical parameters of each virtual synchronous machine unit; constructing a standard dynamic model of the virtual synchronous machine based on the obtained parameters; introducing uncertainty integrated design on the basis of the standard dynamic model of the virtual synchronous machine, and performing equivalent aggregation on all the virtual synchronous machines to obtain a virtual synchronous machine uncertainty model; based on the uncertainty model of the virtual synchronous machine, establishing a cooperative control model by taking system frequency fluctuation minimization as a target; and solving the cooperative control model by using a commercial solver, and solving the power of each device. According to the invention, by constructing an optimization and cooperative control mechanism oriented to frequency support, the problem of over-limit of frequency deviation and frequency change rate is effectively suppressed, and the dynamic response capability of the island micro-grid under the condition of sudden load change is improved.

The invention discloses a Doppler frequency offset estimation method and electronic equipment, and relates to the technical field of communication, and the method comprises the step that the electronic equipment communicates with a low-orbit satellite in a discontinuous reception (DRX) mode. Wherein in a discontinuous reception (DRX) mode, the electronic equipment enters a wake-up period when the wake-up moment arrives, the electronic equipment communicates with a low-orbit satellite in the wake-up period, the electronic equipment enters a sleep period when the sleep moment arrives, and the electronic equipment stops communicating with the low-orbit satellite in the sleep period. When the wake-up moment arrives, the electronic device obtains at least one historical Doppler frequency offset value; and the electronic equipment determines a Doppler frequency offset value corresponding to the wake-up moment based on the historical Doppler frequency offset value. In the scheme, the Doppler frequency offset value at the wake-up moment is estimated through the historical Doppler frequency offset value, and the electronic equipment can calculate the Doppler frequency offset value at the current wake-up moment, so that frequency offset compensation can be carried out in time at the current wake-up moment, and the performance of frequency offset compensation is optimized.

The invention relates to the technical field of audio equipment testing, and discloses a parallel burning and Bluetooth testing frequency calibration method of a special chip for audio equipment. The method comprises the following steps of: establishing an independent serial communication channel with a plurality of chip chips through a computer control unit, and synchronously transmitting a firmware data packet to each chip storage unit; the high-precision radio frequency detection device is started to scan Bluetooth signal frequency offset values of all chips, and detection data is fed back to the computer control unit in real time; screening unqualified chips according to a preset frequency offset threshold, starting a dynamic frequency calibration program for the unqualified chips, and modifying internal capacitance parameters of the chips through a serial communication channel; repeatedly executing the frequency offset detection and capacitance parameter adjustment step until the frequency offset values of all the chips reach a standard range; and after completing the frequency offset calibration, executing a multi-channel Bluetooth performance test and outputting a test result report. According to the method, the chip firmware burning and Bluetooth test frequency calibration efficiency can be improved, the chip performance is guaranteed, and the method is adaptive to the batch production requirement.

The invention discloses an unmanned aerial vehicle wireless signal automatic extraction and amplitude comparison direction finding method based on spectrum data, and relates to the technical field of wireless communication and direction finding, an 8-channel uniform circular array receiving system is adopted, a specific frequency band is scanned, after spectrum data is preprocessed, a time-frequency graph is generated based on short-time Fourier transform, a spectrum peak is extracted through an Otsu algorithm, and the spectrum peak is extracted through an amplitude comparison algorithm; after unmanned aerial vehicle signals are recognized and parameters such as power and frequency deviation are calculated in combination with dynamic time warping and a deep learning classifier, a power ratio matrix is constructed, an azimuth angle is calculated according to a uniform circular array directional diagram function and optimized and calibrated, a track is smoothed through Kalman filtering, and the system has adaptive interference suppression and can adjust receiving bandwidth in real time and start a notch filter. According to the method, through full-process technical innovation, the wireless signal extraction precision and direction finding reliability of the unmanned aerial vehicle in a complex environment are remarkably improved, missing detection and false detection are reduced, and the method has good environment adaptability and anti-interference capability.

The invention belongs to the technical field of clock synchronization. The invention provides an unmanned aerial vehicle communication clock synchronization compensation device and method based on GPS / Beidou second pulse. According to the embodiment of the invention, a second pulse signal and a UTC timestamp are obtained; after several rounds of counting and sliding filtering are carried out on the second pulse signal interval time, the actual frequency and nominal value deviation of the crystal oscillator is calculated; the actual frequency and nominal value deviation of the crystal oscillator are stored, and the crystal oscillator drift model is updated; and dynamically adjusting the output clock frequency according to the nominal value deviation, and compensating the crystal oscillator error to obtain a compensated clock signal. And the second pulse loss duration is monitored, and the crystal oscillator drift model is updated according to the nominal value deviation in the storage module so as to predict the future clock deviation. And within the period of validity of the pulse per second, the clock synchronization error is reduced to improve the synchronization precision. And under the condition of GPS / Beidou, the synchronization precision can be maintained longer than that of a single GPS / Beidou method. And frequency offset automatic compensation along with temperature change can be realized.

The invention relates to the technical field of NV color centers, and discloses an NV color center magnetic field and current measurement method and system. The method comprises the following steps: performing decomposition and noise reduction on the two to generate target three-dimensional data, and constructing a joint response equation by combining the resonant frequency offset and the fluorescence intensity change value of the target three-dimensional data; and finally, decoupling the equation to obtain a global magnetic field estimation value, and determining a current density distribution diagram according to the value and the vacuum magnetic conductivity. According to the method, the initial signal quality is improved through the quantum coherence enhanced pulse sequence, the influence of interference such as environmental thermal noise on the magnetic field signal is effectively weakened through decomposition noise reduction and joint response equation decoupling, and the magnetic field characteristics are accurately extracted, so that high-precision data support is provided for subsequent magnetic field analysis and current density distribution determination. The technical problem that in the prior art, interference such as environmental thermal noise exists generally, so that initially-collected magnetic field signals are mixed with a large amount of noise, and follow-up magnetic field and current analysis is seriously affected is solved.

The invention provides a crimping quality online detection method and system based on acoustic emission signal analysis, relates to the technical field of industrial detection, and solves the technical problems that an existing detection method is not sensitive to early defects and is insufficient in adaptability under complex working conditions. The method comprises the following steps: applying mechanical excitation to the crimping structure, exciting the crimping structure to generate vibration response, and synchronously collecting a vibration response signal and an acoustic emission signal; wherein the mechanical excitation represents sweep frequency excitation or pulse excitation generated by a piezoelectric vibration exciter or an impact hammer so as to excite a plurality of co-frequency offset vibration modes of the crimping structure; calculating the resonant frequency of the crimping structure based on the vibration response signal; calculating frequency offset characteristic parameters according to the resonant frequency based on an inversion method of a physical model; calculating acoustic emission signal characteristic parameters based on the acoustic emission signals; and identifying the type and severity of the crimping defect by utilizing a D-S evidence theory and combining the frequency offset characteristic parameters and the acoustic emission signal characteristic parameters.

The embodiment of the invention provides a signal demodulation method and device, a satellite communication ground receiver and a storage medium, and relates to the field of satellite communication. According to the method, accurate timing capture is realized by performing coarse synchronization on an original received signal, and then the problem of carrier lock loss caused by large-amplitude Doppler frequency shift caused by high-speed motion and the change rate of the large-amplitude Doppler frequency shift is effectively solved by adopting a mode of combining frequency offset correction and dynamic frequency offset compensation; furthermore, a full-field phase compensation sequence is constructed, point-by-point phase correction is implemented, and phase deviation changing along with time is accurately recovered by utilizing an unwrapping and interpolation technology, so that interference of phase ambiguity on demodulation is avoided; and finally, symbol judgment and data demodulation are carried out on the basis of completing frequency and phase double fine correction, so that the error rate is greatly reduced, the robustness and reliability of a satellite communication system under an extreme channel condition are enhanced, and stable and efficient signal recovery under a large-frequency-offset, high-dynamic and low-signal-to-noise-ratio scene is realized.

The invention provides a programmable frequency control array radar waveform generation system and method based on an FPGA, and belongs to the technical field of radar systems and digital signal processing. In order to solve the technical problems of complex hardware system, inflexible parameter adjustment and poor multi-channel synchronism of the traditional frequency control array radar, the invention provides an integrated high-performance solution. The system adopts an FPGA (Field Programmable Gate Array) architecture of an integrated processing system (PS) and programmable logic (PL). The method comprises the following steps: a PS end receives waveform control parameters of an upper computer through a communication interface and transmits the waveform control parameters to a PL end; and a plurality of parallel direct digital frequency synthesizer (DDS) modules in the PL end synchronously generate multi-channel digital baseband signals with programmable frequency offset at high precision according to the parameters under the unified driving of the FPGA global clock network. And the digital signal is subjected to digital-to-analog conversion and radio frequency front-end processing to finally form a transmitting wave beam. According to the invention, flexible programmability of parameters is realized by utilizing a PS-PL collaborative architecture, the synchronization precision of multi-channel signals is remarkably improved through a global clock network and a parallel DDS module generated in the FPGA, and meanwhile, the system has the advantages of high integration level and low complexity.

Certain aspects of the present disclosure provide techniques for generating and processing a frequency multiplexed continuous wave (FMCW) based synchronization signal (SS). According to certain aspects, a method for wireless communication at a wireless node, comprising obtaining a synchronization signal comprising a first frequency modulated continuous waveform signal associated with a frequency that increases in time for a duration according to a first slope and a second FMCW signal that overlaps with the first FMCW signal, wherein the second FMCW signal is associated with a frequency that decreases in time for the duration according to a second slope that corresponds to a negative of the first slope; and performing frequency offset estimation based on the first and second FMCW signals.

A high-frequency power supply system according to the present disclosure includes a first power supply, a second power supply, a first matcher, and a second matcher. The second power supply performs pulse modulation of repeating an ON operation of outputting a second forward wave voltage and an OFF operation of not outputting the second forward wave voltage. The first power supply performs frequency modulation control in a second power supply ON period, and performs frequency offset control of outputting a forward wave voltage VF3 having a fundamental frequency obtained by adding an offset frequency to a fundamental frequency in a second power supply OFF period. The second matcher generates a phase reset signal having a frequency lower than a fundamental frequency based on detection information of a forward wave voltage, and supplies the phase reset signal to the first power supply.

The invention discloses a frequency offset estimation method and device, electronic equipment and a storage medium, and relates to the technical field of communication. The method comprises the following steps: receiving a baseband spread spectrum signal from a low earth orbit satellite to obtain a received signal; performing segmented sweep frequency compensation on the received signal to obtain a compensated measured signal; despreading and descrambling the compensated measured signal by using prior information determined from the received signal, and completing coarse frequency offset estimation on the measured signal despread and descrambled for the first time; and de-spreading and descrambling the signal data after the coarse frequency offset estimation again, and finishing fine frequency offset estimation on the signal data after the second time of de-spreading and descrambling. According to the invention, prior information is introduced to directly lock and track a specified target beam signal, so that the directionality and efficiency of measurement are remarkably improved; by designing a low-complexity signal processing flow, the algorithm burden can be remarkably reduced, it is ensured that adjacent satellite beam frequency offset estimation is rapidly completed in service proceeding, and the real-time requirement of seamless switching is met.

The invention discloses a GNSS (Global Navigation Satellite System) signal sparse compression capture method for a low-correlation measurement matrix, which comprises the following steps of: firstly, constructing a code phase matrix and a frequency offset matrix, and carrying out sparse transformation on a downsampled GNSS signal to obtain a correlation matrix; the method comprises the following steps of: firstly, carrying out iterative optimization on a measurement matrix by taking a Gramb matrix as a matrix, then taking a Frobenius norm of a difference between the Gramb matrix and an equiangular tight frame matrix as a target function, alternately using singular value decomposition (SVD) and a shrinkage operator to carry out iterative optimization on the measurement matrix, and carrying out compression measurement on a correlation matrix through the optimized measurement matrix. Secondly, a correlation matrix of compression measurement is quickly and accurately reconstructed by using a least square operator and an orthogonal matching pursuit algorithm; and finally, when the peak value ratio of the primary peak to the secondary peak of the reconstructed correlation matrix is greater than a threshold value, outputting code phase time delay and Doppler frequency offset corresponding to the primary peak. And if the ratio of the primary peak value to the secondary peak value of the reconstructed correlation matrix is smaller than the threshold value, capturing the GNSS signal again. According to the method, the maximum correlation coefficient and the average correlation coefficient of the measurement matrix can be reduced, the GNSS signal capturing sensitivity is improved, and hardware resources in the signal capturing process in a GNSS receiver can be reduced.

The invention discloses an electrical complete equipment state monitoring and early warning system based on multi-parameter intelligent sensing, belongs to the technical field of electrical equipment state monitoring, and can clearly point out a specific fault mode (such as contact resistance increasing overheating) and a possible position (such as an A-phase bus connection point). Through multi-parameter time sequence feature fusion and an intelligent diagnosis model, deep mining of a fault source is realized, the operation and maintenance efficiency is greatly improved, and the maintenance work is turned from blind troubleshooting to accurate disposal. Weak precursor signals of early and slow faults can be captured by extracting depth time sequence characteristics (such as temperature rise rate and dominant frequency offset rate) strongly related to a fault evolution mechanism. The AI model is utilized to learn complex modes of these precursor, and early warning can be given out before the equipment performance is obviously degraded, so that predictive maintenance of'nipping in advance 'is realized, and unplanned shutdown and major accidents are effectively avoided.