23 results about "Frequency code" patented technology

The application provides a waveform design and receiving method in orthogonal time-frequency code domain. The method comprises the following steps: allocating orthogonal spread spectrum combination to each waveform in a waveform group by using an orthogonal spread spectrum sequence pool; each waveform carries transmission data in the orthogonal time-frequency code domain according to the allocated orthogonal spread spectrum combination; after receiving each waveform, a receiver estimates the multipath time delay, multipath fading and multipath Doppler experienced by multiple waveforms according to the orthogonal spread spectrum combination of each waveform; the receiver detects the transmission data carried by each waveform by using the estimated multipath time delay, multipath fading and multipath Doppler of each waveform, using the MMSE criterion and the orthogonal spread spectrum combination structure. The method of the application designs unique orthogonal spread spectrum combination for different waveforms in the same waveform group, realizes the orthogonal transmission of multiple waveforms under the same DD domain resource, and provides an alternative scheme for multi-user data transmission under high-speed mobile conditions.

The invention discloses a method for distinguishing and quantifying an unconventional oil reservoir CO2 huff and puff recovery ratio improving mechanism, and relates to the technical field of petroleum and natural gas extraction. According to the method, a saturated oil core T2 spectrum and a one-dimensional frequency code are measured on the basis of a nuclear magnetic resonance (NMR) experiment, and the CO2 huff and puff recovery ratio and the CO2 effective action distance are calculated by analyzing the saturated oil core T2 spectrum and the one-dimensional frequency code; a component model is established and calibrated based on experimental data so as to fit the recovery ratio and the CO2 effective action distance in the experiment, and then EOR mechanisms of different CO2 huff and puff stages are distinguished and quantified. According to the method, the yield increasing mechanism in the CO2 huff and puff process can be accurately divided into oil expansion, oil molecule diffusion, elastic energy release and dissolved gas drive, the main control mechanism of CO2 huff and puff yield increasing can be effectively judged, and a basis is provided for optimization of field operation.

The invention discloses a lumbar vertebra scanning processing method and device, a storage medium and electronic equipment, and the method comprises the steps: obtaining a sagittal three-dimensional image of a lumbar vertebra, carrying out the three-dimensional segmentation of the lumbar vertebra and an intervertebral disc in the sagittal three-dimensional image, and obtaining a lumbar vertebra segmentation result and an intervertebral disc segmentation result; inputting the lumbar vertebra segmentation result and the intervertebral disc segmentation result into a preset anatomical key point detection network for anatomical key point identification to obtain an anatomical key point set, and constructing a local vector space based on the anatomical key point set, according to a preset magnetic resonance lumbar vertebra scanning constraint rule, target scanning positioning parameters corresponding to multiple target scanning orientations are matched in the local vector space, and the target scanning positioning parameters at least comprise a phase coding direction, a frequency coding direction, a slice selection direction and a slice center position; and controlling magnetic resonance equipment to execute lumbar vertebra scanning based on the target scanning positioning parameter. The lumbar vertebra scanning parameter planning can be automatically completed.

The application discloses a kind of viewgraph generation methods of cross-modal fusion and multi-frequency coding under ultra-low orbit scene, solve the ultra-low orbit scene of aircraft target, based on the generation of view condition and single picture three-dimensional reconstruction method of priori diffusion, because of insufficient condition information fusion ability, radiation or illumination representation is limited and cross-view geometric constraint is insufficient, it is difficult to obtain the problem that visual coherence and geometric consistency of new view image with texture details under large range of view and scale change simultaneously;The application effectively captures the multi-order angle information of direction distribution to the perception coding of light direction vector, then encodes the position of light starting coordinate, finally encodes the pose of camera pose parameter, can depict the influence of relative attitude on depth perception and perspective distortion in image generation process;The above three encoding results are used in the decoding stage of latent diffusion model, effectively improve the geometric consistency of detail recovery under new view.

The application belongs to the technical field of ground penetrating radar, and provides a ground penetrating radar control method, device, equipment and storage medium, wherein the method comprises: generating a frequency sequence group matrix meeting preset requirements of a ground penetrating radar by using a chaotic mapping, optimizing the frequency sequence group matrix according to a preset genetic algorithm, obtaining an orthogonal discrete frequency coding transmission waveform set, based on the orthogonal discrete frequency coding transmission waveform set, calling a double-channel narrowband, wideband transceiver and a heterogeneous system-level chip of the ground penetrating radar to transmit a waveform to the ground and receive a reflected waveform, analyzing and processing the reflected waveform, obtaining a ground penetrating result, so as to improve work efficiency, meet high-speed operation detection requirements, improve detection accuracy of the radar, have a unique advantage for spectrum analysis and interference suppression, realize a balance between detection depth and resolution, and do not need complex signal processing technology.

The application discloses a long-baseline transceiver-displaced multi-radar signal space-frequency code cooperative anti-jamming method, which comprises the following steps: firstly, according to the identification mechanism of the jammer to the intercepted signal and the interference generation mechanism, the space-frequency code domain cooperative anti-jamming strategy is researched; according to the anti-jamming strategy, the narrow-band detection signal model, the wide-band cover signal model and the optimization problem model are established; the optimized signal is obtained by solving the optimization problem; each station transmits the optimized signal; finally, the receiving station utilizes the matched filter to process the radar receiving echo signal. The method considers the dual functions of cover and decoy, that is, even if the interference energy is large, the jammer generates the parameter error interference signal through the deception of the decoy signal, the interference energy received by the detection signal is greatly reduced, the signal form is more complex, the signal recognition of the countermeasure jammer is more difficult, and the anti-jamming performance of the radar system is improved.

The invention provides an ocean flow field reconstruction method based on multi-modal hybrid filtering and latent code modulation, and relates to the technical field of ocean dynamics analysis, and the method comprises the steps: carrying out the data preprocessing, constructing a space-time sample index, and obtaining a space sampling point coordinate; carrying out context embedding, carrying out mixed frequency coding, then carrying out multiplicative interaction and hierarchical condition modulation to form frequency selective feature representation, and carrying out deep residual stabilization to obtain implicit features of a current residual layer; the operation of the multiple residual layers is repeated until final implicit features are obtained; and generating a reconstructed flow field through coordinate-by-coordinate linear projection based on the final implicit features. According to the invention, tunable multi-scale spectrum expression is formed through mixed frequency coding. And large-scale flow state characteristics and environment background information are represented through hierarchical condition modulation based on context embedding. A multiplicative conditional modulation mechanism is constructed to strengthen high-frequency response, and layer normalization, learnable layer scaling and a random depth regularization mechanism are introduced in a deep feature propagation stage to carry out deep residual stabilization.

The invention discloses a target detection feature enhancement method based on space-frequency cooperative coding, and belongs to the field of computer vision. Firstly, an image to be detected is sent to a target detection network, a spatial domain feature map is extracted, preliminary feature extraction is performed through a convolutional layer, and the feature map is projected to two parallel space-frequency coding branches A and B through channel division; then, modeling and reconstruction of a wavelet frequency domain are carried out on the branch A, and wavelet enhancement path output is obtained; carrying out Fourier frequency domain modeling and reconstruction on the branch B to obtain Fourier enhancement path output; and finally, performing weighted fusion on the feature map, wavelet enhancement path output and Fourier enhancement path output to obtain an enhanced feature Z, inputting the enhanced feature Z into a subsequent detection head of the target detection network, and completing end-to-end training. According to the method, combined modeling of target structure details and semantic contexts is realized by fusing spatial domain and frequency domain information, so that the detection performance and robustness of the model in a complex degradation scene are remarkably improved.

The application provides a binary array space-time-frequency code communication anti-interference method based on intelligent sensing decision, adopts a spectrum sensing technology to listen to and distinguish enemy interference signals, obtains relevant attribute parameters, and intelligently decides a communication mode of a self side according to different interference signal differentiation characteristics, and adopts a binary array space-time-frequency code joint anti-interference technology to improve communication anti-interference capability in various interference scenes including a full-band ultra-wideband interference. The application improves survival capability of a communication system in a complex electromagnetic interference environment. A control strategy of interference sensing and intelligent decision is introduced, a space-time-frequency-code joint anti-interference method is used according to interference signal differentiation characteristics, the system is more intelligent and robust in signal receiving and processing, and reliability of the system is enhanced.

The embodiment of the present disclosure provides a GLONASS system pseudo-range observation calibration method, device, receiver and storage medium, the GLONASS system pseudo-range observation calibration method comprises: obtaining the frequency point and channel number of the original pseudo-range observation; determine the inter-frequency code bias corresponding to the frequency point and channel number of the original pseudo-range observation; according to the inter-frequency code bias determined, the original pseudo-range observation is calibrated, and the calibrated pseudo-range observation is output.The present disclosure can make the GLONASS inter-frequency code bias of all receivers in a reference station network consistent, and also make the GLONASS inter-frequency code bias of receivers of any brand consistent, thereby improving the positioning accuracy of network RTK or PPP service.

The invention discloses a carbonate rock gas reservoir water invasion simulation evaluation method and device. The water invasion simulation evaluation method comprises the steps that after the two ends of a rock core are plugged, nuclear magnetic testing is carried out under the preset temperature and pressure conditions, and a T2 spectrogram and a one-dimensional frequency coding signal in the initial state are obtained; removing the plugs at the two ends of the rock core, and carrying out nuclear magnetic test under the conditions of preset temperature and pressure to obtain a T2 spectrogram and a one-dimensional frequency coding signal measured in a saturated gas state; setting return pressure as the set core pressure, displacing displacement fluid in a high-pressure container to the core, and performing nuclear magnetic test according to a preset sampling interval to obtain T2 spectrograms and one-dimensional frequency coding signals measured at different water invasion moments until the outlet does not produce gas any more; and determining the intruding water quantity and water invasion proportion of pores with different sizes in the initial saturated gas state and different water invasion moments, the water invasion degrees in the initial saturated gas state and different water invasion moments, and the intruding water quantity and water invasion proportion of different rock core positions.

The invention discloses an EEG signal feature extraction method, system and device based on a frequency band-to-attention mapping mechanism, and relates to the field of EEG signal processing, the method comprises the steps that a Transform model is constructed, and the method comprises the steps that a frequency embedding generation module carries out multi-frequency-band decomposition and linear transformation on input data to obtain multiple embedded frequency band features; the frequency coding module introduces a frequency band to attention mapping mechanism, inputs each embedded frequency band feature into different attention heads correspondingly, calculates attention weights, and then fuses and outputs full-frequency band features; training a Transform model by adopting the training sample set so as to obtain an EEG signal feature extraction model; and taking a to-be-analyzed multi-channel EEG signal segment as input data, and sending the input data to the EEG signal feature extraction model to obtain a corresponding risk cognition level. According to the method, the EEG recognition precision can be improved while the calculation efficiency is kept.

This terahertz information metasurface with full-space spatial-frequency cross-domain coding solves the problem of how to effectively utilize electromagnetic resources throughout space to achieve ultrafast real-time switching between transmission and reflection states, belonging to the field of electromagnetic metamaterials. This application includes arrayed metasurface sub-units, which, from top to bottom, consist of a first frequency coding layer, a second dielectric layer, a third metal layer, a fourth dielectric layer, and a fifth transmission-reflection control layer. Real-time switching between reflection and transmission modes is achieved by controlling the conductivity state of photosensitive silicon in the fifth transmission-reflection control layer through wireless optical pumping. In reflection mode, the metasurface sub-units achieve frequency domain coding by regulating the excitation distribution of photosensitive silicon material in the first frequency coding layer; in transmission mode, the metasurface sub-units achieve spatial domain coding by regulating the excitation distribution of photosensitive silicon material in both the first and fifth transmission-reflection control layers, truly realizing cross-domain collaborative modulation at the full-space level.

The invention discloses a method and a system for quickly and accurately controlling the angular position of a multi-radiation source target. The system comprises a target simulator, an array feed unit and a main control unit, a device control code mapping table is pre-stored in the main control unit; the main control unit performs cooperative control on the target simulator and the array feed unit, and the target simulator generates a multi-radiation source target signal, a pulse synchronization signal, a frequency code and a target code; the array feed unit is triggered by a rising edge of a pulse synchronization signal, calls a device control code from a device control code mapping table according to a target code and a frequency code, performs triple branch channel distribution and amplitude-phase modulation on a multi-radiation source target signal, and radiates to a tested device by a spherical array antenna; according to the invention, rapid and accurate simulation of the multi-radiation source target angular position along with pulse synchronization is realized.

The application relates to an ultrathin flexible frequency coding metasurface and a design method thereof, and relates to the field of artificial electromagnetic metamaterials.The frequency coding metasurface designed by the application is composed of optimized reflection type frequency coding supercell structures, the units have different phase-frequency sensitivities, and the coding sequence is designed by utilizing the difference in the phase-frequency sensitivities of the units, so that the continuous regulation of electromagnetic waves is realized.By using a 1-bit coding mode, a two-way beam splitter and a four-way beam splitter can be realized, and by using a 2-bit coding mode, the regulation of a single beam in different directions can be realized.The application has the characteristics of simple structure, easy design, ultrathinness, flexibility, high symmetry, passivity and low cost, and has great application potential and good engineering application prospect in the fields of wireless communication, radar, imaging and signal processing.

A system and method for time / frequency coding with code-division multiple access (CDMA) for interference reduction of vehicle sensors are presented. This system comprises the generation and transmission of a first chirp signal by a first sensor in a first channel and a second chirp signal by a second sensor in a second channel from a vehicle. Both the first and second channels contain a time channel component, a frequency channel component, and a code dimension. A first sensor receives a first reflection signal, and a second sensor receives a second reflection signal, each from one or more objects.Furthermore, the second channel contains one or more different time channels, different frequency channels, or different code dimensions compared to the first channel, and the code dimensions of the first channel and the code dimensions of the second channel are determined from a set of code dimensions based on an estimate of the minimum noise.

The invention provides a GNSS receiver end inter-frequency code deviation estimation method, and relates to the technical field of satellite time service, and the method comprises the steps: obtaining a reference air signal and a to-be-measured air signal correspondingly received by a reference GNSS receiver and a to-be-measured GNSS receiver; smoothing the reference air signal and the to-be-measured air signal corresponding to the current frequency point pair to correspondingly obtain reference pseudo-range information and to-be-measured pseudo-range information; respectively carrying out frequency-to-frequency difference processing on the reference pseudo-range information and the to-be-measured pseudo-range information to correspondingly obtain a reference frequency-to-frequency difference result and a to-be-measured frequency-to-frequency difference result; at the same moment, inter-station difference processing is carried out according to corresponding satellites based on the reference inter-frequency difference result and the to-be-measured inter-frequency difference result, and an inter-frequency code deviation estimation value corresponding to the current frequency point pair is obtained; and executing the operation on all the current frequency point pairs to obtain an inter-frequency code deviation estimation value corresponding to each current frequency point pair of the GNSS receiver to be tested. In this way, the practicability and reliability of the method are improved.

Method for operating a magnetic resonance tomograph for spatially resolved spin resonance measurement of an object, in particular a living object, which is arranged in a static magnetic field B0, whereby an alignment of the object's spins and a longitudinal net magnetization Mz along the direction Z of the static magnetic field results, and wherein a transverse magnetization component Mxy is generated or changed, in particular by generating a spin flip from the Z direction by a desired flip angle, in particular by 90 degrees, by means of at least one high-frequency excitation pulse (1) in spin resonance, wherein spin echo signals from at least one desired volume element of the object are measured using a sequence of high-frequency pulses (4, 5, 7) and switched gradient magnetic fields (2, 3, 6).wherein the at least one volume element is determined by several gradient magnetic fields superimposed at least temporarily on the homogeneous magnetic field B0, wherein the sequence of high-frequency pulses comprises a first (4) and a second high-frequency rephasing pulse (5), in particular a first (4) and second high-frequency rephasing pulse (5) directly after the generation of a transverse magnetization component by means of a high-frequency excitation pulse (1), wherein from the second high-frequency rephasing pulse (5) onwards both a spin echo and a stimulated echo are generated, wherein in addition to a gradient magnetic field (6) in the frequency coding direction, which is switched on during the measurement acquisition to acquire a line of the raw data space, an additional gradient magnetic field (8) in the frequency coding direction is switched on, which generates echo signals or echo signal components newly generated by the high-frequency rephasing pulses (5, 7),in particular, those not attributable to a refocusing of the original spin echo after the first radio frequency rephasing pulse (4) and / or of the original stimulated echo after the second radio frequency rephasing pulse (5), are shifted out of the raw data space or raw data line acquired in a subsequent measurement, characterized in that, during an evolution time (Tau) between the first (4) and second radio frequency rephasing pulse (5), T2*-induced relaxation processes act on a transverse magnetization component present after the first radio frequency rephasing pulse (4), and a magnetization component present in the longitudinal direction after the first radio frequency rephasing pulse (4) remains unaffected, wherein the absolute time between the first (4) and second radio frequency rephasing pulse (5) is extended by the evolution time beyond the duration of an echo interval,which is present between subsequent equidistant high-frequency rephasing pulses (5, 7).

This invention relates to the field of signal playback technology, providing a high-speed broadband signal playback method and device based on variable sampling rate. The method includes: configuring parameters, including interpolation multiples, filter parameters, and frequency codes; interpolating the original signal according to the interpolation multiples; performing serial-to-parallel conversion on the interpolated data to obtain multiple alternating parallel intermediate frequency (IF) data streams; inputting each IF data stream into a multi-function filter, which filters the IF data according to the configured filter parameters; performing digital up-conversion on the filtered IF data according to the configured frequency code; and converting each digitally up-converted data stream through parallel-to-serial conversion to a playback radio frequency (RF) signal. This invention, by converting the variable sampling rate operation of a single high-sampling-rate data stream into a parallel processing design for multiple low-rate data streams, combined with multi-function filter technology, enables stable variable sampling rate operation within an FPGA, adapting to the playback needs of data at different sampling rates.

The invention relates to the technical field of unmanned aerial vehicles, and discloses a crossing machine detection countering method and system, and the method comprises the steps: determining a target frequency hopping sequence based on a LoRa signal transmitted by a crossing machine in real time; determining a frequency matching code of the traversing machine based on the target frequency hopping sequence; according to the technical scheme of countering the traversing machine based on the frequency code, the target frequency hopping sequence and the traversing machine, the traversing machine can be countered in a targeted manner based on the frequency code of the traversing machine instead of the interference of the whole frequency band, so that the targeted countering of the traversing machine is realized, no interference is caused to other communication equipment, and the communication efficiency is improved. And the influence of countering of the traversing machine on peripheral equipment is reduced to the minimum.

The invention discloses a phased-array antenna beam pointing precision correction method, equipment, a medium and a product, and relates to the field of microwave and millimeter wave products. The method comprises the following steps: acquiring input parameters of an antenna beam, wherein the input parameters comprise a target off-axis angle, a target rotation angle and a frequency code; and calling a preset simple pointing precision correction algorithm to carry out correction calculation on the input parameter, and outputting a corrected off-axis angle. Wherein the simple pointing precision correction algorithm is a calculation model generated by fitting based on an actual pointing deviation rule of an antenna; the rule is specifically shown as follows: an actual pointing position in a polar coordinate system presents an elliptical trajectory, and the off-axis angle deviation approaches 90 degrees or 270 degrees along with a target rotation angle and increases along with the increase of frequency. According to the method, a simple algebraic fitting formula is used for replacing a traditional two-dimensional linear interpolation look-up table method, the number of test sampling points of the microwave anechoic chamber is greatly reduced, the test time of the microwave anechoic chamber is greatly shortened, engineering implementation is simplified, and the system cost is reduced.

The application discloses a method, system, device and medium for identifying MIMO-OFDM space-frequency coding mode under alpha stable distribution noise, which comprises the following steps: firstly, performing space-time-frequency coding inter-class identification based on fractional low-order correlation on a received signal; then, extracting a cyclic correlation entropy spectrum feature map of the received signal; and finally, inputting the extracted feature map into a trained deep forest network to identify the space-frequency coding mode; the system and device are based on space-time-frequency coding inter-class identification based on fractional low-order time lag correlation, inter-class identification of unknown signals is realized, and whether space-frequency coding is used is confirmed; the application extracts a cyclic correlation entropy spectrum feature map of a received signal, combines a deep forest network, and converts a coding identification problem into an image identification problem; the application can effectively identify MIMO-OFDM space-frequency coding mode under alpha stable distribution noise, solves the problem that a traditional method is limited in function in non-cooperative communication, and is also applicable to a Gaussian noise environment.

The invention provides a multi-parameter modulation sonar waveform design method based on pulse width Costas coding, a sonar detection system and a computer readable storage medium, and relates to the technical field of underwater sound signal processing and waveform design, and the method comprises the steps: carrying out the system initialization and global parameter configuration; constructing a non-uniform time structure and pulse width coding, and outputting the pulse width of the sub-pulse and the absolute starting moment of the sub-pulse on a time axis; generating a frequency coding sequence, a phase coding sequence and a slope coding sequence, and constructing a multi-dimensional orthogonal modulation parameter space; outputting a complex baseband waveform of the sub-pulse based on the global parameter, the pulse width of the sub-pulse and a multi-dimensional quadrature modulation parameter space in combination with an adaptive slope adjustment strategy; and performing time domain waveform synthesis based on the absolute starting time of the sub-pulse on the time axis and the complex baseband waveform of the sub-pulse to obtain a multi-parameter modulation sonar waveform based on pulse width Costas coding. According to the invention, a non-uniform time structure is constructed, and a periodic high grating lobe is converted into low-level background noise.