574 results about "Modulated continuous wave" patented technology

The invention relates to the field of heart rate monitoring, and discloses a millimeter wave radar breath and heart rate synchronous monitoring method and system, and the method comprises the steps: transmitting a linear frequency modulation continuous wave signal according to a millimeter wave radar, and collecting original echo data reflected by a target region; baseband signal demodulation and phase information extraction are carried out on the original echo data to obtain original phase time sequence data, and the original phase time sequence data comprise thoracic cavity micro-motion features; and according to a Butterworth band-pass filter, preprocessing the original phase time sequence data through human body physiological signal frequency band characteristics to obtain a breathing frequency band signal and a heart rate frequency band signal. According to the method, the apnea event triggering threshold value and the arrhythmia early warning index are updated in real time through Kalman filtering and extended Kalman filtering, so that the monitoring system can dynamically adjust the health parameters, which means that the monitoring system can be optimized in real time and the abnormal health event can be accurately responded in different physiological states.

The invention provides an underwater sonar target detection system and method. The underwater sonar target detection system comprises an optical fiber hydrophone array module which comprises a plurality of optical fiber hydrophone units, each unit comprises an optical fiber Bragg grating sensor and a sound pressure signal demodulation device, and the optical fiber hydrophone array module is used for collecting underwater sound wave signals in real time and converting the underwater sound wave signals into first electric signals; the sonar transmitting-receiving array module comprises a broadband sonar transmitter, a multi-beam receiver and a signal preprocessing circuit, and is used for actively transmitting a frequency modulation continuous wave signal, receiving a target reflection echo and generating a second electric signal; and the multi-mode signal fusion processing module comprises a high-speed data acquisition card, a self-adaptive noise suppression unit and a time-frequency analysis unit. The underwater sonar target detection system and method provided by the invention have the advantages of relatively high reliability, relatively high detection performance, relatively accurate cross-modal signal fusion and capability of performing intelligent target identification and tracking.

The invention provides a nonlinear amplitude-phase error correction method and device suitable for broadband FMCW radar imaging. The method comprises the following steps: establishing a frequency modulated continuous wave radar difference frequency signal model containing a nonlinear error; correcting the amplitude error by adopting an envelope normalization correction method; estimating the high-order polynomial phase error by adopting a method of combining a phase unwrapping recursive least square method and an OShea optimization strategy to obtain a high-order polynomial phase parameter; estimating the periodic multi-sine phase error by adopting a method of combining a MUSIC algorithm and a trust region algorithm to obtain a periodic multi-sine phase parameter; and based on estimation results of the high-order polynomial phase parameters and the periodic multi-sine phase parameters, phase error correction is carried out by adopting a time domain resampling method. The device comprises a nonvolatile memory in which the executable code is stored and a processor, and is used for implementing the method. According to the technical scheme of the invention, the problem that the existing method is generally insufficient in noise immunity can be solved.

The invention provides a frequency-modulated continuous wave laser ranging device based on frequency shift double optical combs, which integrates frequency-modulated continuous wave and double optical comb technologies and comprises an FMCW light source, a beam splitter, a detection and reference light channel, a beam combiner, a photoelectric detector and a processing module. The FMCW light source outputs linear frequency sweeping laser which is divided into two paths through the beam splitter, and the detection light channel detects a target through the first optical comb generator and the circulator. The frequency fFS of the reference optical channel is increased through a frequency shifter, optical combs with different comb tooth intervals are generated by a second optical comb generator, and the fFS and the repetition frequency difference delta fR are in a non-integer multiple relation, so that interference is effectively avoided. After being combined by the beam combiner, the two paths of signals are converted into beat frequency signals by the photoelectric detector, and then time domain signals are spliced by the processing module by using coherence, so that the distance measurement precision is improved. According to the invention, the frequency shift double-optical comb technology improves the precision and anti-interference performance; an efficient data processing algorithm ensures rapid measurement and a wide range of application.

The invention relates to the technical field of laser radars, in particular to an obstacle detection method and system based on a frequency-modulated continuous wave laser radar, and the method comprises the steps: transmitting a chaotic frequency-modulated continuous wave signal to a detection region, and obtaining a reflection echo signal of a target object; performing decoupling calculation on the difference frequency electric signal to obtain a target time frequency distribution matrix; according to the target time-frequency distribution matrix, predicting the Doppler frequency shift amount of the target object at the next moment; based on the chaos frequency modulation adjustment signal, obtaining a distance measurement deviation compensation amount; the chaos frequency modulation adjustment signal is obtained by dynamically adjusting the chaos frequency modulation slope of the chaos frequency modulation continuous wave signal through the Doppler frequency shift amount; and compensating the difference frequency electric signal frequency value of the target object according to the distance measurement deviation compensation amount and the environmental noise data so as to solve obstacle distance speed detection information. According to the invention, the Doppler frequency shift amount is predicted in real time and the chaotic frequency modulation continuous wave signal parameters are dynamically adjusted, so that the accurate compensation of the distance measurement deviation is realized, and the accuracy of obstacle distance speed detection is improved.

A monitoring system is presented for monitoring vital signs of subject(s). The monitoring system includes a control system configured for signal communication with a frequency modulated continuous wave (FMCW) radar to process measured data which is received from a single-channel front end of receiver of said FMCW radar and which is in the form of data matrix indicative of consecutive beat signals. The control system comprises a data processing utility comprising: a localization module configured and operable to process the measured data indicative of said data matrix and provide support recovery data indicative of the received signals originated at localized one or more subjects; and a vital signs monitoring module configured and operable to analyze the support recovery data and monitor vital signs of said localized one or more subjects.

The invention discloses a non-contact electrocardio detection method which comprises the following steps: transmitting a frequency modulation continuous wave signal to the heart part of a human body by using an MIMO millimeter wave radar so as to obtain an echo signal reflected by the human body and pre-process the echo signal to obtain a discrete three-dimensional radar signal; enhancing the discrete three-dimensional radar signal by using a 2D beam forming technology to obtain a 2D signal; extracting a target area signal from the 2D signal, and performing phase extraction on the extracted target area signal to obtain phase data; the method comprises the following steps: constructing a WaveGRU-Net network comprising an MODWT module, a CNN module and a Bi-GRU module; and training the WaveGRU-Net network by using the phase data so as to output a reconstructed electrocardiogram by using the trained WaveGRU-Net network, thereby realizing non-contact electrocardiogram detection. According to the method, accurate extraction of the electrocardiosignal is realized, and meanwhile, the signal reconstruction precision is improved.

A system for emulating an over-the-air environment for testing a Frequency-modulated Continuous Wave (FMCW) light detection and ranging (LiDAR) unit under test (UUT). The system includes an optical lens system that receives an FMCW laser signal from the LiDAR UUT, and provides the signals to one or more optical fibers. A slope, chirp timing and intensity of the FMCW laser signal is determined using digital signal processing, and a modulation waveform is determined to emulate an over-the-air (OTA) environment based at least in part on the slope, chirp timing, and intensity. An in-phase quadrature phase (IQ) modulator modulates the FMCW laser signal using the modulation waveform and provides the modulated laser signal back through the optical lens system to the LiDAR UUT.

The invention relates to an unmanned aerial vehicle detection method based on a frequency modulated continuous wave radar, and belongs to the field of radar technology and deep learning. The objective of the invention is to solve the problems of low detection accuracy, low robustness and low reliability of an existing unmanned aerial vehicle. The method comprises the following steps: obtaining a trained new feature extractor, a feature fusion unit and an unmanned aerial vehicle detection network; extracting the echo signal of the unmanned aerial vehicle from the echo signal to be detected, and performing micro-Doppler feature extraction to obtain micro-Doppler features; inputting a to-be-detected echo signal into the trained feature extractor, and outputting deep features by the trained feature extractor; based on a trained feature fusion unit, performing feature fusion on the micro-Doppler features and the deep features to obtain dynamically weighted fusion features; and inputting the dynamically weighted fusion features into the trained unmanned aerial vehicle detection network, and outputting a detection result by the trained unmanned aerial vehicle detection network.

The invention discloses a non-contact electrocardiosignal monitoring reconstruction method and system based on time-frequency domain combination, and relates to the technical field of radar signal processing, and the method comprises the following steps: obtaining a chest wall vibration signal S of a to-be-detected person by adopting a frequency-modulated continuous wave radar; separating a heart mechanical motion signal SH from the chest wall vibration signal S; and converting the heart mechanical motion signal SH into an electrocardiosignal ECG through a pre-established ResNet architecture neural network model. Time domain loss and frequency domain loss are used for training a ResNet architecture neural network model, and the error between the calculated heart rate and the real heart rate is quantified through the mean absolute error and the root-mean-square error. According to the method, the neural network capable of being used for ECG signal conversion is designed based on the ResNet architecture, after the neural network is subjected to data training, more detailed signal features can be learned, the fitting accuracy is improved, then the ECG waveform can be accurately predicted, and non-contact electrocardiosignal monitoring and reconstruction are achieved.

An optical frequency domain reflectometer with environmental disturbance resistance and large strain measurement capability belongs to the field of distributed optical fiber sensing and comprises an opposite sweep frequency light frequency modulation continuous wave signal generation module, a light splitting device, a modulation device, a circulator, a polarization controller, an optical coupling device, a photoelectric conversion module and a data acquisition and processing module. An optical signal generated by an opposite sweep frequency light frequency modulation continuous wave signal generation module is divided into probe light and local oscillation light through a light splitting device, the probe light is modulated through a modulation device and sent to an optical fiber through a circulator, and a Rayleigh back scattering light signal generated by the optical fiber and the local oscillation light interfere in an optical coupling device to obtain interference light; the photoelectric conversion module mixes beat frequency signals of interference light, and the data acquisition and processing module analyzes and processes the beat frequency signals. According to the invention, the position information of the Rayleigh backscattering point is marked by using the modulated probe light, the Rayleigh scattering signal at the corresponding position is restored, crosstalk between channels is inhibited, and high-precision measurement in a large dynamic range and resistant to environmental disturbance is realized.

Methods, systems, and devices for wireless communications are described. Generally, the described techniques enable a first wireless device to scramble at least a portion of one or more frequency-modulated continuous wave (FMCW) signals (e.g., hybrid FMCW signals) using a scrambling identifier, which may enable a second wireless device to differentiate between FMCW signals based on identifying the scrambling identifier. For example, the first wireless device may scramble at least a portion of an upchirp signal, a downchirp signal, or both, of an FMCW signal. The second wireless device may identify the scrambling identifier based on attempting to descramble the scrambled portion of the FMCW signal using multiple candidate scrambling identifiers. In some examples, a scrambling pattern (e.g., which portion of the upchirp signal, downchirp signal, or both, is scrambled) of a hybrid FMCW signal may indicate information associated with the first wireless device.

The invention discloses a flood flow early warning method, a controller, a storage medium and a program product, and relates to the field of hydrological monitoring and disaster early warning. By adopting the technical scheme, after an emergency flow meter emits a first frequency modulation continuous wave to the water surface at the current position, the controller receives a first signal reflected by the water surface and analyzes the spectrum characteristic of the first signal; therefore, the stratified flow phenomenon of the water body is effectively identified. After the emergency flow velocity meter emits a second frequency modulation continuous wave to the water surface at the current position, the controller receives a second signal reflected by the water surface, determines the surface flow velocity and the subsurface flow velocity through the first signal, the second signal and a preset flow velocity calculation formula, and calculates the comprehensive flow velocity by combining the water flow layering coefficient; and finally, flow calculation is performed according to the section coefficient and the actually measured water level. According to the multi-level flow velocity measurement and analysis method, the accuracy of flood flow calculation is remarkably improved, when the instantaneous flow exceeds the preset flow threshold value, early warning is given out in time, and important support is provided for flood prevention and flood fighting.

Disclosed are systems and techniques for wireless joint communications and sensing. For example, a network device can receive, from a network entity, at least one configuration signal indicating at least one configuration comprising a resource for a physical uplink control channel (PUCCH) and for sensing. The network device can output, for transmission to the network entity, the PUCCH based on the at least one configuration comprising the resource. The network device can transmit a sensing signal based on the at least one configuration comprising the resource.

The invention discloses a breath and heartbeat detection method and system based on an FMCW (Frequency Modulated Continuous Wave) radar. The method comprises the following steps: acquiring a continuous wave signal sent by an FMCW millimeter wave radar to detect a target object so as to obtain a reflected echo signal; the echo signals are preprocessed; separating a respiration signal from a heartbeat signal of the preprocessed echo signal based on an EPH multi-stage cooperative signal processing algorithm; and carrying out anomaly correction on the separated instantaneous frequency anomaly data based on a local weighted regression algorithm. Therefore, the vital sign detection accuracy of the radar can be improved under the interference conditions of background noise, signal harmonic waves and the like.

The invention provides a blood pressure detection method and device based on a frequency modulated continuous wave radar and electronic equipment, and can be applied to the technical field of signal processing. The method comprises the steps that a radar echo signal is acquired, and the radar echo signal is acquired at a preset height position away from a neck-chest area of a target object; performing beam focusing processing and phase demodulation processing on the radar echo signal to obtain pulse wave signals at different positions and angles in the neck-chest area; pulse wave time features and pulse wave clustering features of the pulse wave signals are extracted, the pulse wave time features represent phase information of pulse waves collected at different positions in the neck-chest area, and the pulse wave clustering features represent the similarity between the pulse waves collected at different angles in the neck-chest area; inputting the pulse wave time features and the pulse wave clustering features into a blood pressure detection network, and outputting a blood pressure detection result of the target object.

The invention provides a frequency modulated continuous wave laser radar-based target identification method and a laser radar system, which can be applied to the technical field of laser radars. The method comprises the following steps: acquiring an interference beat frequency signal after polarization orthogonal demodulation; performing signal demodulation on the electric signal of the interference beat frequency signal to obtain a target detection feature; performing feature matching on the target detection features and a typical target polarization feature library to obtain a feature matching result; and under the condition that the feature matching result represents that the target feature similarity meets a first threshold condition, performing identification processing on the target detection features based on an air intrusion target identification model to obtain a target type identification result.

The embodiment of the invention discloses a nonlinear correction method and system for a frequency-modulated continuous wave laser, and the method comprises the steps: obtaining a phase curve of a to-be-corrected beat frequency signal based on an nth voltage signal, determining the frequency modulation nonlinearity according to the phase curve, carrying out the sampling processing of a plurality of phase points in the phase curve, and obtaining a plurality of target phase points, and finally, an (n + 1) th voltage signal is determined according to the multiple target phase points and the nth voltage signal, the (n + 1) th voltage signal is used for nonlinear correction of a frequency modulation continuous wave laser in the system, and n is an integer greater than 0 in sequence until the frequency modulation nonlinearity is smaller than or equal to a frequency modulation nonlinearity threshold value. Therefore, the nonlinear correction of the frequency-modulated continuous wave laser in the nonlinear correction system of the frequency-modulated continuous wave laser is realized, the distance measurement and speed measurement precision can be prevented from being damaged, and the performance of an FMCW radar is remarkably improved.

The photonic integrated chip comprises a substrate, a demultiplexer and a light guide assembly, and the light guide assembly and the demultiplexer are integrated on the substrate; the light guide assembly comprises a first light splitting coupler, a second light splitting coupler and a frequency mixer, and the first light splitting coupler is in optical communication connection with the output end of a corresponding channel of the demultiplexer so as to allow the demultiplexer to transmit an optical signal to the first light splitting coupler; the first light splitting coupler is used for splitting a received optical signal into local oscillation light and signal light, and the first light splitting coupler is in optical communication connection with the second light splitting coupler and the frequency mixer so as to allow the first light splitting coupler to transmit the local oscillation light to the frequency mixer and transmit the signal light to the second light splitting coupler; the second light splitting coupler is used for transmitting the signal light to a detection object and receiving echo signal light fed back by the detection object, and the second light splitting coupler is in optical communication connection with the frequency mixer so as to allow the second light splitting coupler to transmit the echo signal light to the frequency mixer.

The invention discloses a frequency modulated continuous wave laser radar phase noise compensation method. The frequency modulation continuous optical signal is divided into two paths: a measurement path and an auxiliary path; the frequency modulation continuous optical signal of the measurement path is divided into two paths, one path is used as a reference optical signal, the other path is used as a detection optical signal to be emitted to a target, and beat frequency is carried out on the received target reflection optical signal and the reference optical signal to obtain a beat frequency signal of the measurement path; the frequency modulation continuous optical signal of the auxiliary path passes through a Mach-Zehnder interferometer with a fixed time delay difference and then is subjected to beat frequency to obtain an auxiliary path beat frequency signal; searching and determining the frequency of the beat frequency signal of the measurement path, and extracting the phase noise in the beat frequency signal of the auxiliary path; estimating the phase noise of the measurement path; and finally compensating the phase noise. The invention also discloses a frequency modulated continuous wave laser radar phase noise compensation device. Compared with the prior art, the calculation amount of digital processing can be greatly reduced.

The invention provides a radio altimeter with a pre-biased local oscillator. The radio altimeter comprises a transmitting signal source module used for generating a frequency-modulated continuous wave signal; the pre-bias local oscillation module is used for generating a pre-bias frequency-modulated continuous wave local oscillation signal which is synchronous with the transmitting signal source module but lagged in phase; the radio frequency control module is used for controlling the transmitting signal source module and the pre-bias local oscillator module; the frequency mixer module is used for mixing the pre-bias local oscillator signal with a received ground echo signal to generate an intermediate frequency signal containing a pre-bias frequency; and the calculation circuit module is used for calculating the current height value according to the intermediate frequency signal. The system is simple and easy to implement; the lowest height measurement range of the frequency-modulated continuous wave altimeter can be effectively reduced; the original radio frequency feeder line is shortened or cancelled, the link loss is reduced, and the transmitting power is improved.

The invention is suitable for the technical field of distance measurement, and provides a distance detection method and device for an underwater target, electronic equipment and a program product. The method is applied to a frequency-modulated continuous wave laser detection system, and a signal receiving end of the frequency-modulated continuous wave laser detection system comprises a two-dimensional matrix detector array composed of a plurality of single-photon avalanche photodiodes. The method comprises the following steps: transmitting a plurality of first laser signals with different frequencies to an underwater target through a signal transmitting end of a frequency-modulated continuous wave laser detection system; receiving second laser signals with different frequencies through a plurality of single-photon avalanche photodiodes; performing two-dimensional discrete synthesis processing on the second laser signals with different frequencies to obtain target echo signals; and determining the distance between the underwater target and the frequency-modulated continuous wave laser detection system according to the target echo signal. According to the frequency-modulated continuous wave laser detection system, a plurality of laser signals with different frequencies can be transmitted and received, so that the detection distance and the resolution ratio of an underwater target can be improved.

A mechanism for generating a modulation signal for use in a radar system. The modulation signal includes a sequence of chirps. Each chirp includes an active period, a transition period and an idle period. During the active period, the frequency of the chirp moves from a start frequency to an end frequency. During the transition period, the frequency of the chirp moves towards the start frequency of the next chirp. The rate of change of the frequency, during the transition period, is different for different chirps of the modulation signal.

The invention relates to the technical field of frequency-modulated continuous wave radars, and discloses a nonlinear error correction method, system and device for an FMCW radar and a medium, and the method comprises the steps: obtaining a difference frequency signal containing a nonlinear error, and extracting a first time frequency signal; performing phase fitting on the first time frequency signal to obtain a first time frequency signal error coefficient, and performing error coefficient conversion on the first time frequency signal error coefficient to obtain a difference frequency signal error coefficient; constructing a matching signal according to the difference frequency signal error coefficient, and performing demodulation and low-pass filtering on the difference frequency signal according to the matching signal to obtain a residual signal; judging a signal type, and calculating a residual signal error coefficient by adopting a corresponding optimization algorithm; and combining the difference frequency signal error coefficient and the residual signal error coefficient to obtain a phase error correction factor, and performing nonlinear correction on the resampled difference frequency signal according to the phase error correction factor. The estimation precision of the nonlinear error coefficient can be improved, and the overall performance of a radar system is improved.

In described examples, a frequency modulated continuous wave (FMCW) radar includes a reference clock, a phase locked loop (PLL), a pulse generator, a counter, a chirp ramp control circuit, and a synchronization state machine. The reference clock generates a reference clock signal. The PLL generates a feedback clock signal in response to the reference clock signal, and an output signal in response to the feedback clock signal. The pulse generator outputs a chirp start pulse in response to the reference clock signal. The counter increments a count in response to the feedback clock signal. The synchronization state machine provides a chirp ramp signal to a chirp ramp control circuit in response to the reference clock signal, the feedback clock signal, the chirp start pulse, and the count. The chirp ramp control circuit causes the PLL to ramp a frequency of the output signal in response to the chirp ramp signal.

The invention discloses a machine tool cutter space pose on-machine measurement device and a measurement method thereof, and the device comprises a calibration module which is installed at one side of a cutter handle of a cutter; a frequency-modulated continuous wave laser interference system and a galvanometer are installed on a vibration isolation workbench of the machine tool, light beams emitted by the frequency-modulated continuous wave laser interference system achieve conversion of a set angle through the galvanometer so as to cover the calibration module, and a space positioning algorithm is adopted to fit the plane where the target ball is located. And obtaining a deviation value between the mass center and the normal vector in two measurement results before and after machining, and taking the deviation value as the tool space pose error before and after machining of the machine tool, so that rapid and high-precision direct measurement of the tool space pose error is realized. The method has the advantages of being large in measurement range, high in measurement precision, simple in structure and low in cost, and the defect that in an existing method, the position and pose errors of the tool are indirectly calculated through an error model is overcome.

This application provides a signal transmission method, a communication apparatus, and a communication system, that serve to suppress interference between signals of a plurality of transceivers sharing a same resource. In the method, a first apparatus generates parameter information and sends the parameter information to a second apparatus, such as a transceiver. The parameter information may be determined based on one or more multiplexing modes. The parameter information indicates a value of at least one of a time shift of a time for transmitting a frequency modulated continuous wave (FMCW) signal relative to a reference time, a slope of the FMCW signal, a plus-minus sign of the slope, and a coding parameter used to generate the FMCW signal through phase coding. The second apparatus receives the parameter information and, generates the FMCW signal based on the received parameter information, and sends the FMCW signal.

The embodiment of the invention provides a structural strain and displacement monitoring method and system based on active microwave reflection. Frequency modulated continuous wave microwave signals are simultaneously transmitted to a target object through a plurality of microwave transceivers, and echo signals are received; extracting a target object distance in the sight line direction of each microwave transceiver and corresponding deformation and vibration information from the baseband signal; establishing a vibrating target multi-dimensional deformation and vibration reference coordinate system according to the spacing of the plurality of microwave transceivers and the distance between the microwave transceivers and the target object, obtaining a corresponding geometric length relationship, and calculating the coordinate of the target spatial position on each coordinate axis of the coordinate system; and performing weighted fusion reconstruction according to the projection of the target deformation and vibration on each coordinate axis in the coordinate system and the distance proportion from the target to each microwave transceiver, and recovering the actual multi-dimensional deformation and vibration information of the target object. The problems that in the prior art, dependence on the environment is high, precision is poor, and efficiency is low are solved, and the limitation that a microwave vibration measurement technology can only achieve single-dimensional measurement in the sight line direction is solved.

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 radar device may generate an integrated range-velocity map by combining data from a plurality of range-velocity maps. Each range-velocity map may be associated with a respective radar channel from a plurality of radar channels. The radar device may identify a first peak in the integrated range-velocity map. The first peak may indicate one or more radar targets in the integrated range-velocity map and being identified by a first bin having a first range-velocity bin index. The radar device may determine a first data set by extracting, from each range-velocity map, data that is included in a respective bin associated with the first range-velocity bin index. The radar device may process the first data set to determine a first set of phase imbalances associated with the plurality of radar channels.