465 results about "Doppler frequency" patented technology

The invention relates to the technical field of communication, and discloses a network communication chip signal interference suppression processing method. The method comprises the following steps: acquiring a local oscillator phase jitter sequence in real time through an on-chip phase noise monitoring unit; estimating Doppler frequency shift and channel coherence time based on the sequence; dynamically adjusting the closed-loop bandwidth of the phase-locked loop; and generating a phase compensation signal, and performing time-varying channel minimum mean square error equalization in combination with a received baseband signal to eliminate inter-symbol interference. The system integrates a phase noise monitoring function module, a channel parameter estimation function module, a phase-locked loop bandwidth regulation function module, a phase compensation generation function module and an interference joint elimination function module. By means of dynamic bandwidth reconstruction and high-precision phase compensation, the bit error rate under high-speed movement is remarkably reduced, the 5G millimeter wave communication standard requirement is met, and the method has the advantages of being achieved on a whole chip, low in delay and high in robustness.

The invention discloses a communication-detection integrated sonar signal design method and device based on multi-pulse composite modulation, and the method comprises the steps: dividing a total frame period into a detection sub-frame and a communication sub-frame, enabling the detection sub-frame to achieve the high-resolution distance measurement through employing a bidirectional linear frequency modulation (BILFM) signal, a communication sub-frame adopts a multi-frequency multi-phase composite modulation (MTPM) signal to realize high-bit-rate data transmission; after band filtering, orthogonal demodulation, low-pass filtering and down-sampling preprocessing are carried out on detection sub-frame echoes, distance and speed information is extracted by adopting fast-time low-sampling two-dimensional fast Fourier transform (2D-FFT), unambiguous Doppler frequency is recovered by utilizing the Chinese remainder theorem (CRT), and accurate speed measurement of long-distance and high-speed targets is realized; a communication subframe receiving signal is subjected to IQ demodulation after down-conversion, Costas loop carrier synchronization and matched filtering, and multi-frequency multi-phase coded data are extracted. According to the method, the time-frequency collaborative design of detection and communication is realized, the distance resolution and the speed measurement range are considered, and the signal bandwidth utilization rate and the underwater information transmission reliability are remarkably improved while the system complexity is kept low. The device comprises a processor and a memory, and an executable program for implementing the method is stored in the memory. The technology can be widely applied to the fields of unmanned underwater vehicles, ocean monitoring, underwater sensing networks and the like.

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.

A measurement and control simulation device based on a measurement and control data transmission integrated system comprises an upper computer display control test module, a PC host module, a signal processing master controller module, an isolation DC / DC module, a down-conversion module, a filtering module, an isolator module and an outer end face interface module. The system has the characteristics of multiple modulation systems, a spread spectrum function, controllable output power, Doppler frequency change and the like, can be used for simulating a star chain control system link test in a ground test system, and fully improves the index assessment performance during system docking; meanwhile, the design of a down-conversion link meets the requirements for the strength and sensitivity of the received signal, the stability and accuracy of the radio-frequency signal after frequency conversion in a low-power injection state are remarkably improved, and a new scheme is provided for a high-frequency conversion mode. Besides, the display control module of the equipment has the functions of multiplexing, reconstruction, multi-data interaction and the like, so that multifunctional and multi-task full-system test coverage can be realized, the cost investment of test systems such as spacecrafts and the like is greatly reduced, and the multifunctional index test coverage efficiency is improved.

The present application relates to the field of wireless communications. Provided are a Doppler frequency shift compensation method and apparatus, and a device and a storage medium. The method comprises: acquiring ephemeris information of a satellite; on the basis of the ephemeris information and a first frequency shift value which is estimated using a beam position center, compensating for a synchronization signal block (SSB) within a beam position, and sending a pre-compensated SSB to a terminal; and then, on the basis of a second frequency shift value, which has been updated via interpolation, compensating for an uplink signal and a downlink signal within the beam position, and sending a pre-compensated downlink signal to the terminal. A terminal can perform Doppler frequency shift compensation without relying on GNSS location information, thereby reducing the cost and usage power consumption of the terminal, decreasing the number of times that the terminal performs frequency sweeping in an initial access stage, and shortening the latency for the terminal to access a cell.

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.

A method and apparatus for separating transmission channels of a DDMA-MIMO radar, a device, and a storage medium. The method comprises: dividing a Doppler frequency domain into N transmission channels according to the number M of transmitters comprised in a DDMA-MIMO radar (S110); establishing an initial correspondence between the M transmitters and any M transmission channels (S120); determining measured range-Doppler amplitude information and reference range-Doppler amplitude information corresponding to the N transmission channels (S130); determining correlation information between the measured range-Doppler amplitude information and the reference range-Doppler amplitude information (S140); and determining a target correspondence between each transmitter and transmission channel on the basis of the correlation information and the initial correspondence (S150).

The invention relates to an IRNSS navigation signal simulation generation method and system based on parameter compensation, and the method comprises the steps: receiving original signal data outputted by an IRNSS navigation receiver, and receiving a target machine position coordinate and a velocity vector; analyzing the navigation message to extract ephemeris parameters, and calculating the real-time position and velocity vector of the satellite; calculating a Doppler frequency compensation value and a pseudo code time delay compensation value; according to the pseudo code time delay compensation value and a preset target simulation coordinate, modifying a signal emission time field in the navigation message, generating a simulation navigation message frame, carrying out forward error correction coding processing, generating a coding symbol sequence, and carrying out modulo-two addition operation on the coding symbol sequence and a pre-generated PRN pseudo code sequence to obtain a baseband spread spectrum signal; generating an intermediate frequency carrier signal according to the Doppler frequency compensation value and the carrier phase; and modulating the baseband spread spectrum signal to the intermediate frequency carrier signal, and outputting an intermediate frequency analog signal. According to the invention, the concealment of signal simulation and the success rate of capturing the analog signal by the target receiver can be improved.

A single-station positioning method based on Doppler frequency shifts and time difference information, and a system and an electronic device. The method comprises: acquiring an actual period of a pilot signal sent by an unmanned aerial vehicle (S1); on the basis of the actual period of the pilot signal sent by the unmanned aerial vehicle, determining two adjacent target signals sent by the unmanned aerial vehicle in a target area, and acquiring actual center frequencies of target signal information, an actual time difference of arrival between the two target signals at a receiving base station, actual angles of arrival, and actual Doppler frequency shifts of the unmanned aerial vehicle (S2); importing an actual range of the target area, the actual period of the pilot signal, the actual center frequencies of the target signals, the actual time difference and the actual angles of arrival into variables in a preset theoretical Doppler frequency shift model, so as to obtain a theoretical Doppler frequency shift value table, wherein the table comprises different theoretical Doppler frequency shift values corresponding to different distances from the unmanned aerial vehicle to the receiving base station (S3); performing error metric calculation processing on the actual Doppler frequency shifts and each theoretical Doppler frequency shift value, so as to obtain a theoretical Doppler frequency shift value corresponding to the minimum error metric (S4); and on the basis of the theoretical Doppler frequency shift value corresponding to the minimum error metric, determining the positions at which the unmanned aerial vehicle sends the target signals (S5). The method can ensure the accuracy of single-station positioning in a complex scenario.

The invention discloses a time-frequency offset tracking method in a Tiantong satellite monitoring low-orbit satellite system, which belongs to the field of satellite communication, and comprises the following steps: acquiring satellite orbit information, satellite ephemeris information and positioning information of a low-orbit satellite, and resolving current Doppler frequency offset information; performing frequency pre-compensation according to the Doppler frequency offset information, and performing compensation by using the frequency offset captured by the FCCH; the satellite-borne terminal receiver carries out carrier frequency estimation by using a downlink channel, so that the carrier residual frequency difference of a received signal is estimated, and frequency correction is carried out; starting downlink timing tracking; uplink frequency offset compensation is started, so that the frequency of a signal from the low-orbit satellite to the Tiantong satellite is the expected carrier frequency of the Tiantong satellite; and carrying out transmission timing correction by adopting the spaceborne terminal timing drift rate, and carrying out uplink timing adjustment. According to the method, normal access and stable data transmission of the satellite-borne terminal can be realized.

The invention relates to the technical field of precision measurement and instrument testing, in particular to a test error analysis method based on a high-precision acoustic phased array Doppler log, and aims to solve the problems that a traditional Doppler log mostly adopts a black box model driven by pure data, explicit modeling of a sound wave propagation and array receiving physical mechanism is lacked, and the test error analysis accuracy is poor. The problems that the generalization ability is weak under errors such as channel amplitude-phase mismatch and emission nonlinearity, real Doppler frequency shift is difficult to accurately extract, and the credibility of speed estimation cannot be quantified, so that output in a complex underwater environment is unreliable are solved. Physical priori such as an acoustic wave equation, a Doppler effect and array manifold is embedded into a neural network, physical consistent modeling and efficient reasoning of multi-channel echoes are achieved, an uncertainty quantification mechanism based on the evidence theory is further introduced, and the reliability and the likelihood of velocity estimation are dynamically evaluated, so that the reliability and the reliability of velocity estimation are improved. And the robustness and interpretability of the system in a complex underwater environment are effectively improved.

The invention discloses a satellite Internet of Things uplink signal detection method and a satellite Internet of Things uplink signal detection system, which integrate traditional signal processing and advanced spiking neural network technologies, realize high-precision frame synchronization by performing two-dimensional cross-correlation matching in a time-frequency domain, and perform low-power-consumption and high-robustness symbol judgment by using an event-driven spiking neural network. Compared with a traditional method based on FFT or matched filtering, the method has higher adaptability and detection performance in a satellite Internet of Things scene with large Doppler frequency shift, low signal-to-noise ratio and dense users.

The invention discloses a Doppler frequency shift compensation method, a Doppler frequency shift compensation device and electronic equipment. The method comprises: a user equipment receiving a first message issued by a satellite, the first message carrying a first compensation value corresponding to a Doppler frequency shift between the satellite and the user equipment, and the first compensation value being used for pre-compensating a downlink signal sent by the satellite; in response to the first message, determining the distance between the user equipment and the beam center position of the satellite; and under the condition that the distance is greater than a preset threshold value, performing post-compensation on the frequency deviation of the received downlink signal according to the first compensation value. According to the invention, the technical problem that the accuracy of satellite compensation and the power consumption of terminal compensation cannot be effectively balanced in a Doppler frequency offset compensation scheme adopted by the related technology by adopting a sending end compensation or receiving end compensation mode is solved.

The application provides a user positioning method and device for low-orbit satellite communication and satellite network equipment, relates to the technical field of satellite communication, and the device comprises a receiving unit configured to receive a transmission delay and a Doppler frequency shift reported by a terminal device; a first processing unit configured to control the satellite network equipment to perform the following first operation: calculating a first included angle from the terminal device to a subsatellite point via a satellite according to the transmission delay and an orbital height of the satellite; calculating a second included angle from the subsatellite point to the terminal device in a satellite moving direction via the subsatellite point from a satellite overhead angle according to the first included angle, the Doppler frequency shift, a carrier frequency and a satellite moving speed; and determining position information of the terminal device according to the first included angle and the second included angle. The application can automatically estimate the position information of the terminal device without the terminal device reporting the position information, ensure the service continuity of a communication architecture depending on the terminal device information, and protect the user privacy and safety.

The invention relates to the technical field of satellite communication, and discloses a low-orbit satellite communication Doppler frequency offset processing method, system and device and a medium, and the method comprises the steps: separating a pilot signal from a received signal; taking the Doppler frequency as a first system state, taking the received signal as first observation data, and performing Doppler frequency offset estimation on the pilot signal by adopting a frequency offset estimation algorithm to obtain a frequency offset estimation value; taking the Doppler frequency as a second system state, taking the frequency offset estimation value as second observation data, and adopting a frequency offset tracking algorithm to perform Doppler frequency offset tracking on the pilot signal to obtain a frequency offset tracking value; and performing frequency offset compensation on the received signal according to the frequency offset tracking value to obtain the received signal after frequency offset compensation. According to the method, the Doppler frequency offset is subjected to streaming processing through Bayesian filtering in the estimation and tracking stages, the complexity of data storage and calculation is effectively reduced, the data updating rate is increased, and therefore the accuracy of low-orbit satellite data is effectively improved.

The invention relates to the technical field of intelligent sensors, in particular to an unmanned aerial vehicle track intelligent tracking method based on a millimeter-wave radar, which comprises the following steps: receiving echo signals collected by the front end of the millimeter-wave radar, carrying out constant false alarm rate detection and Doppler frequency shift extraction on the echo signals, generating an unmanned aerial vehicle target space coordinate set, and carrying out target tracking on the unmanned aerial vehicle. And mapping the target space coordinate set of the unmanned aerial vehicle to a three-dimensional Euclidean space. According to the method, a non-convex optimization objective function containing beam switching time cost and precision constraint is constructed, and mathematical optimal solution of radar beam resources is realized. The generated adaptive scheduling instruction is used for adjusting the pulse repetition frequency and the beam residence time, it is ensured that radar front-end parameters dynamically evolve along with the target state, overall centroid tracking is emphasized for rigid body formation so as to save resources, independent high-frequency refreshing is emphasized for discrete targets so as to ensure the precision, and the accuracy is improved. And the continuity and robustness of trajectory tracking of the unmanned aerial vehicle in a complex electromagnetic environment are improved.

The invention discloses an encryption burst communication receiving method based on an FPGA, and belongs to the technical field of burst communication. According to the invention, the problems of poor synchronization performance and poor anti-interference capability at the receiving end in the existing method are solved. According to the method, the carrier synchronization range is expanded by introducing the pilot frequency to enable the synchronization heads to be '1', the limitation that a conventional frequency offset estimation algorithm can only work under the condition that the Doppler frequency shift is smaller than 0.5 times of the symbol rate is broken through, and the capacity of the system for adapting to the high-dynamic environment is improved. A spreading code continuous tracking working mode is designed, coarse estimation and synchronization are carried out in a frame header part, spreading codes are still adopted in an information part, and continuous tracking is carried out, so that the system can adjust the phase of the spreading codes in real time in the whole frame to solve the problem of phase error accumulation caused by adopting a low-precision clock; the problems that when one frame of data at the sending end is long, the synchronization performance is reduced when a low-precision clock is adopted, and even effective synchronization cannot be achieved are solved. The method can be applied to the field of burst communication.

The application discloses a kind of mobile communication base station and communication method, communication method includes: communication base station sends pilot configuration instruction to user, carries out estimation to Doppler frequency offset, obtains phase-compensated received pilot signal, and is converted into vectorization received signal;Linear regression model is constructed, adaptive sparse channel estimation is carried out based on variational bayes inference, and output downlink frequency domain channel matrix, angle domain channel matrix;Angle domain channel matrix is quantized using Lloyd-Max non-uniform quantizer, and the global channel matrix of base station end is obtained;Output optimal analog precoding matrix and digital precoding matrix;Communication base station generates radio frequency signal based on precoding after transmission signal vector, and sends to user.Communication base station includes distributed antenna unit, baseband processing unit, radio frequency link and central control unit.The technical scheme of the application covers the whole process signal processing link of mobile communication base station, and the calculation complexity is low, and can be directly adapted to existing 3GPP standard and hardware platform.

Provided are a communication method and a communication device, relating to the technical field of communications, the method being applied to a first communication device, the method comprising: the first communication device obtaining an estimated value of Doppler frequency offset between the first communication device and a second communication device; obtaining the distance between the first communication equipment and the second communication equipment according to the estimated value of the Doppler frequency offset; and calculating a timing advance according to the distance, wherein the timing advance is used for synchronization between the first communication equipment and the second communication equipment. According to the method, the distance between the satellite and the user equipment and the timing advance can be calculated under the condition that the user equipment cannot obtain the position information of the satellite and the position information of the user equipment.

The invention provides a signal-to-noise ratio estimation method and device suitable for PSK (Phase Shift Keying) modulation. The method comprises the following steps: calculating the average power of an input signal sequence; estimating the average power of the pilot frequency sequence; and calculating a signal-to-noise ratio. According to the method, the influence degree of noise on the distance between the PSK modulation signal and the original point in the constellation diagram is estimated, a traditional method for calculating the signal-to-noise ratio by estimating the deviation degree of the actual signal from the ideal signal due to the influence of noise is replaced, high accuracy can still be kept when the signal is influenced by Doppler frequency deviation and sampling deviation, the method is more suitable for an actual communication system, and compared with the prior art, the method has the advantages of simple operation and low cost. In an actual communication system, signal-to-noise ratio estimation is usually carried out after signal timing synchronization and carrier synchronization processing, however, the signal-to-noise ratio calculation method provided by the invention can be used for estimating the signal-to-noise ratio after synchronization before synchronization according to PSK modulation characteristics, and has certain application advantages in scenes such as switching modulation waveforms according to the signal-to-noise ratio.

The invention discloses a TDM-MIMO radar Doppler phase offset compensation method based on iteration, and the method comprises the steps: carrying out the equivalent conversion of a TDM-MIMO radar model into a one-transmitting-multiple-receiving virtual array model, building a signal receiving model of a virtual array, and obtaining a beat signal; constructing a target echo space-time joint matrix; constructing an airspace signal vector based on the target initial Doppler frequency; and performing iterative estimation on target angle estimation and Doppler frequency, and estimating the angle by using a phase offset compensation result. According to the method, the Doppler frequency is scanned more meticulously by constructing the Doppler frequency scanning manifold matrix, the Doppler frequency dimension and the angle dimension are decoupled, the space-time combined two-dimensional estimation is converted into two one-dimensional estimation, and the accurate Doppler frequency and angle are obtained after few times of iteration.

The present application relates to the technical field of frequency adaptive switching, and discloses a frequency adaptive switching method in a distributed wireless network, comprising: setting a target time period, a switching trigger holding time and an upper limit of false trigger probability, combining the center frequencies of a service frequency band and an adjacent frequency band, obtaining and calculating a cross-frequency band signal quality difference sequence and an intra-band standard deviation; then, according to the terminal position change and the average moving speed in the target time period, selecting a dominant frequency and calculating an effective Doppler frequency, establishing a monotonic relationship between the effective Doppler frequency and the intra-band standard deviation; finally, combining the holding time and the false trigger probability constraint, solving a dynamic hysteresis threshold to realize adaptive frequency switching. The method can flexibly adjust the switching parameters according to the dynamic changes of the user moving speed and the wireless environment, effectively reduce the risk of excessive switching and ping-pong switching, ensure that the false switching probability is within a controllable range, and thus significantly improve the accuracy, stability and resource utilization efficiency of network switching.

This invention provides a fast Doppler localization method based on opportunistic signals. The method includes: establishing instantaneous Doppler frequency shift measurements for each satellite based on the receiver's initial position and velocity information, the wavelength of the opportunistic signal, and the position and velocity information of each satellite; establishing an instantaneous Doppler localization equation based on the relationship between the instantaneous Doppler frequency shift measurements for each satellite and the receiver's position information; determining regularization parameters using the variance expansion factor method; obtaining constraint parameters based on the regularization parameters and the stable functional; and solving the instantaneous Doppler localization equation under the condition of minimizing the constraint parameters to obtain the instantaneous Doppler localization result based on the opportunistic signal. The localization result includes the receiver's final position information, final velocity information, and frequency offset.

A self-calibration atomic wavemeter, including a saturated absorption spectrum optical path based on saturated absorption spectrum to lock the probe laser frequency on cesium atomic energy level transition line; a double-peak spectrum optical path scans the coupling laser frequency after the probe laser frequency is locked by the saturated absorption spectrum, when the probe laser and the coupling laser jointly act on the alkali metal atom and resonantly excite, the electromagnetic induced transparency effect is generated; and when the probe laser is detuned, the probe laser and the coupling laser jointly act on the alkali metal atom to produce non-resonant excitation, and the double-peak EIT spectrum with Doppler frequency shift is generated, based on the linear relationship between the double-peak spectrum interval and the probe laser detuning amount, the wavelength measurement of the current probe laser can be completed, in addition, the double-peak spectrum interval and the atomic energy level transition frequency are compared, and the difference between the two is taken as an error signal feedback to the control end of the probe laser, and the frequency of the probe laser is tuned to the reference frequency benchmark, so that the calibration of the wavemeter can be realized.

This invention discloses a method for correcting positioning errors of missile-borne SAR, specifically relating to the field of satellite positioning technology. It is used to solve the problem of unstable positioning error correction caused by the non-rigid deformation between the antenna phase center and the inertial navigation unit not entering the continuous solution chain during high-dynamic flight. By synchronously acquiring satellite positioning observation residuals and raw acceleration data, an acceleration gradient sequence is generated. In the first update cycle, the reference non-rigid deformation vector is extracted and a model degradation command is generated. In the second update cycle, the dynamic spatial offset of the antenna phase center is extrapolated, and then a Doppler frequency shift compensation sequence is generated by projecting along the instantaneous line-of-sight direction of the synthetic aperture radar and fed forward into the radar processor.

The invention discloses a target micro-Doppler extraction method based on vernier ranging, which belongs to the technical field of radar signal processing, and comprises the following steps: obtaining radar vernier ranging data through first-order and second-order difference; the de-noising effect is verified according to the statistical standard deviation; performing modal decomposition by adopting a CEEMDAN algorithm to obtain an intrinsic mode function matrix and a residual matrix; and Fourier transform is performed on each component, and the frequency corresponding to the maximum amplitude value is extracted as a micro-Doppler frequency value. According to the target micro-Doppler extraction method based on vernier ranging, the high-precision characteristic of vernier ranging and the CEEMDAN anti-aliasing capability are combined, random errors are effectively reduced, the micro-Doppler extraction precision is improved, and the method is adaptive to nonlinear and non-stationary radar signals and is suitable for radar target fine recognition scenes.

The invention provides a method for acquiring timing advance (TA) and a related device, the method is applied to a terminal, the terminal communicates with a satellite in a first channel, and the method comprises the following steps: acquiring Doppler frequency offset of the first channel, acquiring a first elevation angle corresponding to the Doppler frequency offset of the first channel based on a pre-configured corresponding relationship between the Doppler frequency offset and the elevation angle of the satellite, and sending the first elevation angle to the terminal; the distance between the terminal and the satellite is calculated through the first elevation angle, TA is obtained based on the distance, and the TA is used for compensating for service link time delay between the terminal and the satellite. According to the technical scheme, the elevation angle is obtained based on the pre-configured corresponding relation between the Doppler frequency offset and the elevation angle of the satellite, position information of the terminal does not need to be used, and therefore even if the terminal cannot use a positioning mode such as GNSS positioning, the TA for compensating the service link time delay between the terminal and the satellite can be obtained, and the TA for network communication is obtained.

The embodiment of the invention provides an interference source positioning method based on an unmanned aerial vehicle and related equipment, and belongs to the technical field of communication. The method comprises the following steps: controlling the unmanned aerial vehicle to perform first motion according to a first linear path, and collecting a first data set in the first motion process; the unmanned aerial vehicle is controlled to perform second motion according to a second linear path, a second data set in the second motion process is collected, the first data set and the second data set both comprise the signal frequency, the motion speed and the unmanned aerial vehicle position of each time node, and the first linear path and the second linear path are not parallel; based on the Doppler frequency shift principle, calculating a first included angle between the interference source incoming wave direction and the first motion direction according to the first data set, and calculating a second included angle between the interference source incoming wave direction and the second motion direction according to the second data set; determining the interference source position according to the first angle and the second angle. The interference source positioning efficiency and positioning precision can be improved.

This application relates to the fields of SAR signal processing and marine remote sensing applications, and provides a method and apparatus for sea surface current field inversion based on electromagnetic vortex wave radar data. The method determines the Doppler spectrum using electromagnetic vortex wave radar image data, obtains the measured frequency position of the trough feature point in the Doppler spectrum, and determines the theoretical frequency position using the position and angle of the two main lobes and the angle of the trough feature point in the radar antenna pattern. Then, the difference between the measured frequency position and the theoretical frequency position is used to obtain the anomalous frequency offset. Next, the Doppler frequency offset caused by wind and wave motion is removed from this anomalous frequency offset to obtain the target Doppler frequency offset. Finally, the radial velocity of the sea surface is calculated using the Doppler frequency offset, thus realizing sea surface current field inversion. This effectively expands the applicability of the Doppler frequency shift-based ocean current inversion method and improves the application potential of electromagnetic vortex wave radar in sea surface current field detection.

The application provides a kind of based on multimodal sensing of bad grain conveying state monitoring method and system. Wherein, by arranging the multi-axis laser speed probe with dust cover on both sides of the conveying belt, eliminate the interference of dust on light path. Synchronous acquisition of surface layer particle laser doppler frequency shift signal and deep layer particle echo intensity data, establish layered control body model. Use echo intensity to compensate scattering signal, generate flow velocity distribution profile by autocorrelation processing. Further adopt optical flow method to construct particle motion vector field, calculate collision energy value through vector field energy distribution. When the energy value exceeds the preset threshold, generate positioning early warning signal, realize real-time monitoring and accurate positioning of particle collision anomaly. The technical scheme provided by the application can realize full-dimensional monitoring of particle motion state in the process of bad grain conveying in high dust environment, effectively identify collision anomaly and accurately locate the fault area, and ensure the quality of bad grain conveying.