449 results about "Main lobe" patented technology

The invention relates to the technical field of signal analysis, in particular to a GNSS (Global Navigation Satellite System) detection method and system based on machine learning, and the method comprises the steps: receiving a navigation radio-frequency signal containing reality and deception, and carrying out the down-conversion of an RF (Radio Frequency) front end to obtain intermediate-frequency data; gNSS signal capture is completed by searching correlation peaks in frequency and code phases based on intermediate frequency data; in the capturing stage, a motion state, a correlation peak number, a noise value, capturing parameters and peak + / -1 chip sampling features are extracted and input into a machine learning classification model to judge whether cheating exists or not; if so, separating the deception signal from the real signal, and respectively sending the deception signal and the real signal into independent tracking channels; measuring an array element carrier relative phase by an array antenna, establishing a phase center model, and correcting to obtain an effective phase center and a differential baseline; according to the method, a deception azimuth angle and a pitch angle are obtained, a beam weight is calculated, a deception direction is subjected to null setting, a real direction is subjected to main lobe protection, and a weight value is fed back in real time to improve a signal carrier-to-noise ratio and locking stability. According to the invention, the problem that the existing commercial GNSS signal is low in power and easy to be interfered by deception is solved.

The invention discloses a phased array weather radar calibration method based on a generalized metal ball calibration theory. Comprising the following steps: in a microwave anechoic chamber, collecting two-dimensional antenna pattern data of a phased array weather radar in at least one working mode and pointing to a plurality of different beams; performing numerical integration on the two-dimensional antenna pattern data, calculating a combined beam main lobe solid angle of the transmitting antenna and the receiving antenna, and calculating an equivalent beam width product; calculating a calibration theoretical reflectivity factor of the metal ball based on the product of the theoretical radar scattering sectional area and the equivalent beam width of the metal ball; actual detection echo data of the phased array radar on the metal ball under different working modes and beam pointing is acquired, and an actual reflectivity factor is calculated; and comparing the actual reflectivity factor with the calibration theoretical reflectivity factor to complete calibration of the phased array weather radar. Aiming at the non-Gaussian working mode of the phased array weather radar, the reflectivity factor of the phased array weather radar can be quantitatively evaluated, and the radar detection performance is improved.

The invention discloses a high-precision spectral interference signal demodulation method for micro distance measurement. The method comprises the steps of S1, interference spectrum shaping; measuring an interference spectrum and a reference spectrum; selecting a six-item combined cosine window as a primary function of an interference signal to obtain a shaped interference spectrum; s2, performing non-uniform Fourier transform to obtain a frequency spectrum of the target signal; s3, on the basis of a multi-spectral-line interpolation algorithm, interpolation is carried out on the window function to solve a fitting function, and a center frequency k is obtained; and S4, outputting a result. And solving and outputting an optical path difference d. According to the method, a six-item cosine combination window is selected as a primary function of an interference signal, and the problem that the accuracy of signal extraction is influenced by mutual superposition of side lobes and even main lobes of a direct current item and a solved frequency item is solved; an interference spectrum is processed by using a fast non-uniform Fourier transform algorithm, accuracy can still be kept under the conditions that the distance to be measured is increased and sampling is gradually sparse, and the problem of resampling deviation caused by a traditional interpolation method can be solved.

The invention relates to the technical field of radar waveform optimization, in particular to a synthetic broadband waveform optimization method based on reinforcement learning. According to the method, a deep reinforcement learning framework is adopted, and end-to-end optimization is carried out on the center frequency and amplitude parameters of multiple sub-pulses. The method comprises the following steps: constructing a synthetic broadband waveform signal model, and parameterizing sub-waveforms to determine a search space of an optimization problem; converting a waveform optimization problem into a reinforcement learning form, and defining a state space, an action space, a reward function and a state transition mechanism; based on a deterministic soft action value iteration strategy algorithm, point spread function features are extracted in combination with a Transform encoder, and sub-pulse parameters are dynamically adjusted. Through the method, the main lobe resolution can be effectively suppressed and improved, the target detection performance of a radar system is improved, and the method has good global optimization capability and environmental adaptability and is suitable for cognitive radar and adaptive waveform design scenes.

The invention provides a passive antenna array beam forming test method and system, and relates to the technical field of beam forming test. According to the method, channel baseline parameters are established in a silencing environment, frequency hopping and channel switching are combined to realize multi-frequency-point synchronous sampling, a reference source and self-polling data are utilized to calculate a mutual coupling correction matrix and a feeder line consistency factor, and weight projection and equivalent aperture field generation are completed without changing physical wiring conditions; further extracting a main lobe direction, a beam width, a side lobe level and a scanning consistency index through far field transformation, and unwrapping and smoothing a frequency-point-crossing phase result; and meanwhile, generating a unique traceability identifier, establishing full-link association between a test condition and a result, and outputting a criterion conclusion. According to the method, the accuracy, efficiency and traceability of passive array beam testing are improved.

The invention discloses a harmonic and inter-harmonic parameter detection method and device based on a self-multiplication convolution window algorithm, and belongs to the field of signal detection, and the method comprises the steps: obtaining a discrete time domain signal, and carrying out the windowing and mapping of the time domain signal based on the self-multiplication convolution window algorithm, and obtaining a frequency domain signal; calling a quantum particle swarm algorithm to estimate the frequency domain signal to obtain an estimation parameter matched with a preset frequency spectrum; and performing nonlinear error compensation on the estimation parameter by using a preset space-time attention residual network to obtain harmonic and inter-harmonic parameters. According to the method, signal leakage can be suppressed by windowing the signal, the energy of the main lobe of the frequency spectrum is more concentrated, the frequency domain signal is estimated by using the quantum particle swarm algorithm, the evaluated frequency spectrum meeting the actual demand can be quickly screened, and finally, the frequency spectrum is compensated, so that the error can be further reduced, and the detection precision can be further improved.

The invention relates to the technical field of communication, and discloses an anti-interference communication sensing integrated beam forming method and system. The method comprises the following steps: generating an integrated waveform based on an orthogonal signaling base and a random data symbol; the sensing ranging performance is evaluated through periodic and non-periodic autocorrelation functions, time-frequency resource allocation of the waveform is optimized based on the performance, and an optimized waveform is generated; obtaining channel state information, carrying out interference source identification, and calculating a beam forming weight according to an identification result; mapping the optimized waveform to a time-frequency resource lattice of a frame according to orthogonal frequency division multiplexing to generate a frame structure signal; inputting the frame structure signal into a multi-antenna array, and regulating and controlling the phase and amplitude of each antenna unit through a beam forming weight to form a directional beam with a main lobe aligned with a target and a null aligned with interference; the target and interference changes are monitored in real time, the beam forming weight and waveform time-frequency resource allocation are dynamically updated, the anti-interference capability is improved, and the communication perception integration performance is enhanced.

The invention relates to a time domain broadband adaptive beam forming method and system based on Chebyshev weighting, and belongs to the field of array signal processing. Aiming at the technical problems of poor real-time performance and high sidelobe of the existing broadband beam forming, the method comprises the following steps of: dividing a received broadband signal into a plurality of sub-bands, obtaining an optimal weight vector for each sub-band by adopting a minimum linear constraint iterative algorithm after down-conversion, constructing an expected response of an FIR filter according to each weight, obtaining a filter coefficient through L2 norm convex optimization, and finally obtaining a high sidelobe beam according to the expected response of the FIR filter. And performing time domain weighting on each array element signal by using a filter bank, and outputting a directional beam. According to the method, the calculated amount is low, a main lobe and interference null can be formed in real time in a broadband, and a certain side lobe height is kept.

The invention discloses a non-line-of-sight moving target three-dimensional reconstruction method based on an MIMO millimeter wave radar, and is applied to the technical field of radar target detection in a complex urban environment. Aiming at the problem of difficulty in realizing three-dimensional reconstruction of a non-line-of-sight moving target in the existing radar target detection technology, the method comprises the following steps: firstly, establishing a non-line-of-sight multipath propagation model, and exporting a multipath signal model of an MIMO millimeter wave radar; the invention further provides a multipath signal departure angle (DoD) / arrival angle (DoA) unambiguous estimation algorithm, and solves the problem that a main lobe and a grating lobe are difficult to distinguish in the DoD / DoA estimation process of an existing commercial MIMO radar. And finally, proposing a path-oriented non-line-of-sight target three-dimensional positioning algorithm, respectively positioning the non-line-of-sight target by using different paths, and fusing different path positioning results to form a three-dimensional point cloud. According to the method, three-dimensional reconstruction of a plurality of non-line-of-sight moving targets can be realized, and the correlation problem between paths does not need to be considered.

The invention discloses a Shack-Hartmann wavefront detector centroid calculation method and related equipment, and relates to the field of optical measurement, and the method comprises the steps: obtaining a light spot array grayscale image, detecting the local maximum value of each light spot, and dividing sub-aperture image regions corresponding to micro lenses one by one according to the local maximum value; extracting a gray matrix of each sub-aperture image region, respectively determining one-dimensional regions of a light spot main lobe in row and column directions, and intersecting to obtain a main lobe region; a main lobe area is deducted from the sub-aperture image area to form a threshold calculation area, and the maximum gray value of the threshold calculation area is selected as a threshold; and performing threshold reduction on pixels in the sub-aperture image area, setting a negative value to zero, and calculating the position of the mass center of the light spot based on the processed image. According to the method, sub-aperture adaptive threshold and local background removal are realized, weak light spot information loss caused by a unified threshold is avoided, and the precision of centroid calculation and wavefront restoration is improved.

The application discloses a method for simultaneously resisting suppressing interference forward-looking imaging of a missile-borne forward-looking array radar, adopts an array antenna in a cut-off track direction to receive echoes of a forward-looking area, and samples to obtain distance-pulse-array three-dimensional echo data; pulse compression in the distance direction is performed on the three-dimensional echo data, a pulse compression reference function and a migration correction factor are multiplied in the frequency domain, and high resolution in the distance direction is realized; multi-channel receiving data of each distance-pulse unit is selected, and is sequentially arranged to form a corresponding space snapshot of the unit; a covariance matrix of interference and noise is established, and the maximum likelihood estimation value of the target angle and amplitude in the interference environment is approximately solved by using an adaptive single-pulse algorithm on the space snapshot signal of each distance-pulse unit after distance pulse compression; and the angle measurement result is projected to the distance-azimuth domain, and through space coordinate conversion, a two-dimensional forward-looking imaging diagram is obtained. The application realizes high-resolution imaging of a forward-looking target while effectively suppressing main lobe suppressing interference.

The invention relates to the technical field of information, and discloses a self-adaptive radio frequency energy capture method and system, and the method comprises the steps: collecting radio frequency signals in an environment, separating independent components of each frequency band signal from the radio frequency signals, determining the power density distribution and main lobe direction of each frequency band signal, and determining the deviation main direction of each frequency band signal; the antenna element spacing and the reference value of phase adjustment are determined by combining the expected gain requirement of the current environment, so that the antenna array configuration data are determined, the antenna array is controlled to scan the uncovered range of each frequency band signal, and then the full / directional capture mode is dynamically switched. The energy collection efficiency data in the current capture mode is evaluated to determine the target frequency band with sidelobe interference, the reference value of the target frequency band is adjusted, and the signal focusing effect is determined through the adjusted reference value to determine the capture priority of each frequency band signal, so that the radio frequency energy collection efficiency in the complex electromagnetic environment is effectively improved; and efficient capture and utilization of multi-band weak radio frequency signals are realized.

The invention relates to the technical field of laser radar detection, in particular to a frequency-modulated continuous wave laser radar high-precision distance measurement method, which comprises the following steps of: 1, firstly, performing noise suppression by using an improved FTRLS (Fast Transverse Recursive Least Squares) adaptive filtering algorithm aiming at a low signal-to-noise ratio signal; 2, adjusting the added limitation and filter parameters, iterating the optimal parameters, and applying the optimal effect to subsequent spectrum correction; 3, windowing the denoised signal, and carrying out FFT (Fast Fourier Transform) to obtain a frequency spectrum of the signal; and 4, smoothing the signal by using a Butterworth filter, suppressing a side lobe of a frequency spectrum due to the characteristics of the filter, and highlighting the energy of a main lobe of the signal and the position of a spectrum peak. According to the method, a redundancy feedback-dynamic restart mechanism is applied to an adaptive filtering algorithm RLS, the FTRLS algorithm which is added with a transverse filter and leads to reduction of denoising precision is greatly improved, numerical divergence of the FTRLS algorithm is inhibited by using a regularization factor, and the signal-to-noise ratio is improved.

The invention relates to the technical field of radar information, in particular to a ground clutter suppression method for a ground reconnaissance radar, which comprises the following steps of: firstly, establishing a clutter profile map by using echo data, judging information inside and outside a clutter according to the clutter profile map, and selecting different signal processing flows, namely, adopting a detection channel 1 outside the clutter, adopting a detection channel 2 and a detection channel 3 inside the clutter and adopting a detection channel 2 and a detection channel 3 outside the clutter; after the detection channel 1 passes through the MTD filter, clutter suppression processing is not carried out, and a detection result is output; the detection channel 2 is a coherent processing channel, firstly performs mean filtering processing, then performs coherent processing, performs clutter suppression processing through phasor mean filtering, and outputs a detection result; and the detection channel 3 is a zero Doppler processing channel and is used for detecting a low-speed target in a clutter area, compared with the prior art, the method can reduce Doppler sidelobes as much as possible on the premise of ensuring that the ground clutter height is suppressed, and has the minimum main lobe width and the minimum signal-to-noise ratio loss.

The invention provides a non-uniform sampling rotation MIMO super-resolution imaging method, system and product, and the method comprises the steps: synthesizing a virtual aperture based on collected radar data, and building a coordinate system based on the virtual aperture; calculating position information of the radar antennas in the coordinate system, and screening all the radar antennas based on a preset step length to obtain effective virtual antennas; acquiring target distance information based on the acquired radar echo signal; constructing a rotating super-resolution dictionary based on the target distance information and the position information of the effective virtual antenna, and generating a local super-resolution image based on the rotating super-resolution dictionary; and performing coordinate transformation and data splicing on each local super-resolution image to generate a global super-resolution image. Compared with a traditional angle estimation algorithm, the method provided by the invention can greatly improve the angle resolution capability, enables the main lobe of the radar to face the target at any time through the rotatable characteristic of the platform, enables the monitoring area of the radar to be enlarged, improves the target detection capability, and meanwhile, the radar has the advantage of flexible deployment.

The invention relates to a radar target recognition method and device under main lobe jamming based on prior information assistance, and the method comprises the steps: constructing a point distribution function under jamming capable of depicting jamming characteristics and an HRRP distortion rule, effectively extracting jamming prior information, and combining a multi-scale feature extraction network layer and a cross attention fusion mechanism to recognize a radar target under main lobe jamming. Deep fusion of HRRP features and interference prior information is realized, so that the target recognition accuracy and robustness of the model under typical interference conditions such as intermittent sampling and forwarding are remarkably improved. Therefore, the problems that in the prior art, under the typical interference condition, the radar target high-resolution range profile recognition robustness is poor, and the recognition accuracy is reduced are solved.

The invention provides a bistatic synthetic aperture radar track planning method and system based on structure driving, and relates to the technical field of radar track planning, and the method comprises the steps: building a BiSAR echo model based on a target scattering model; analyzing the imaging characteristics of the target under different configurations, and revealing the constraint relationship between the target structure representation and the configuration; constructing a structure-driven multi-stage trajectory planning model based on the constraint relationship between the target structure representation and the configuration; the trajectory optimization is modeled as a multi-objective optimization problem; through a non-dominated sorting genetic algorithm based on target scattering characteristic driving, a multi-target optimization problem is solved so as to plan a platform track in each stage. According to the method, the limitation of a point target model in an existing trajectory planning method can be broken through, all main lobe observation configurations capable of presenting target structure information are optimized, the retention degree of the target structure information in a BiSAR imaging result is effectively improved, and the interpretability of the image is remarkably enhanced.

The invention discloses a main lobe gain maximization method for an analog-digital hybrid array of a radar communication system. According to the method, the ratio of the maximum minimum main lobe level to the peak side lobe level is used as a target function, and under the main lobe ripple constraint, the simulation weight constant modulus constraint and the digital weight power constraint, the ADMM (Alternating Direction of Multiplexing) is used for carrying out joint design on the simulation weight and the digital weight. In the ADMM framework, a Riemann conjugate gradient method is adopted to solve a simulation weight subproblem with constant modulus constraint; and solving a digital weight by adopting a Lagrange multiplier method. A numerical result shows that the method can generate better main lobe ripples and lower peak side lobe level, and has good beam directional diagram accurate control performance.

The invention discloses a radar measurement method, device and equipment, a medium and a product, and relates to the technical field of radar signal processing. According to the method, a space angle is divided into a main lobe area and a side lobe area; determining a phase modulation strategy of twice observation of the radar; the phase modulation strategy comprises the steps that phases of a main lobe area are kept consistent in two observations, and the phase difference of a side lobe area is 180 degrees; according to a phase modulation strategy, determining a directional diagram of expected radiation of the array antenna in two times of observation, and optimizing a unit excitation weighting vector in two times of observation to obtain an optimized value of the unit excitation weighting vector; according to the optimization value, performing phase modulation on a transmitting signal of the array antenna; and coherent superposition is carried out on echo signals reflected by the target and received by the radar in two times of observation. On the premise that the array size is not changed, the anti-interference capability and the spatial resolution of the radar are remarkably improved, and the monitoring precision of the radar on parameters such as distance, speed, deformation and angle is effectively improved.

The invention provides an anti-noise interference frequency parameter estimation method for high-precision optical coherence ranging, which comprises the following steps: acquiring a spectral interference signal of an optical low-coherence interference system and a reference light spectral signal output only by a reference arm, and converting the spectral interference signal into interference signals with wave number space arranged at equal intervals, carrying out spectral density amplitude normalization to obtain a standard interference signal so as to eliminate interference of light source spectrum fluctuation and non-uniform sampling on frequency estimation; hanning window modulation is applied to a standard interference signal, spectrum leakage is suppressed, spectrum analysis is performed on the modulated signal, a peak value and an adjacent secondary peak value of a spectrum main lobe are extracted, a frequency correction amount is calculated based on a peak value and secondary peak value amplitude ratio relation derived by a Hanning window spectrum mode function, and an accurate frequency of the interference signal is obtained; and calculating the displacement of the object to be measured according to the product of the accurate frequency and the spectral resolution of the optical low-coherence interference system in combination with the refractive index of the light in the measurement medium.

Systems and methods are described for generating and implementing pulse-shaping filters for efficient utilization of limited spectral resources in wireless communication systems. Wireless communication systems operating at high spectral efficiency conventionally use pulse shaping filters that rely on Nyquist waveforms for good main lobe performance with low inter-symbol interference (ISI) power. Conventional uses of non-Nyquist waveforms typically involve an orthogonalization process to convert those non-Nyquist waveforms to Nyquist waveforms for ISI free performance. Embodiments of pulse shaping filters described herein generate a non-Nyquist partial response (NNPR) transmit filter and / or matched receive filter based on applying a tunable second-weighted orthogonalization to a tunable first-weighted non-Nyquist waveform to obtain a pulse-shaping waveform with parametric control over throughput and power penalty.

A system and method for distinguishing targets of interest from main lobe clutter and sidelobe clutter includes an ESA or AESA divided into subarrays. A sum beam power profile is produced via one or more scans of the subarrays, and a difference beam power profile is produced via calculations involving the subarrays. A comparison of the sum beam power profile and the difference beam power profile accentuates signal power disparities between targets of interest and clutter. A threshold is then applied to isolate targets of interest. Different difference beam power profiles may be used for elevation comparisons and azimuth comparisons. Alternatively, subarrays may be selected such that the same difference beam power profile may be used for both elevation and azimuth. Scans may be time multiplexed such that data from different scans may be used to produce the sum beam power profile, the difference beam power profile, or both.

According to the SAR anti-interference method based on the multiple orthogonal frequency modulation waveform design disclosed by the invention, the waveform agility number and orthogonality can be improved while the low sidelobe imaging performance is ensured; in addition, according to the method, a segmented high-degree-of-freedom frequency modulation coding structure is adopted, and the long-distance imaging requirement of a satellite-borne SAR system under the condition of a large time bandwidth product can be met. The method comprises the following steps: S1, constructing a multi-target signal optimization model for minimizing a peak sidelobe ratio and cross-correlation peak energy; s2, designing an improved adaptive genetic algorithm for solving a non-convex complex waveform optimization problem; s3, an MOFM waveform with accurate spectrum control capability is obtained through algorithm optimization; s4, effective suppression of main lobe active interference is realized by using the designed waveform; compared with a traditional linear frequency modulation waveform, the method has the advantages that the low sidelobe characteristic is kept, meanwhile, the orthogonal agility number is remarkably increased, and the method is suitable for the anti-interference imaging requirement of a modern spaceborne SAR system.

A quad-polarized antenna system according to the present invention comprises a plurality of RF chains, and an antenna array in which rows of first dual-polarized antenna units and rows of second dual-polarized antenna units are alternately arranged in a horizontal direction. The first dual-polarized antenna unit and the second dual-polarized antenna unit have different dual polarization characteristics from each other. The rows of first dual-polarized antenna units are used to form at least one first beam and at least one second beam which have + / −45° polarizations, and the rows of second dual-polarized antenna units are used to form at least one third beam and at least one fourth beam which have 0° / 90° polarizations. The first beam, the second beam, the third beam, and the fourth beam are formed towards different spatial directions, and the first and third beams correspond to main lobes, and the second and fourth beams correspond to grating lobes.

The invention discloses a microphone array layout optimization method based on IGSA, and belongs to the field of sound source localization. The method comprises the following steps: firstly, constructing a topological structure of a microphone array as a rectangular array; then, the directivity and the directional diagram of the microphone array are adopted to express the performance of the microphone array; constructing a fitness function through the width of a main lobe, the level of a side lobe and the number of microphones; then, on the basis of a genetic algorithm, improving crossover and mutation steps, adopting a hierarchical crossover strategy and a similarity regulation and control mutation strategy, and simultaneously optimizing an array structure by a simulated annealing operator in an interspersed manner; and finally, outputting the optimal microphone array arrangement to meet the requirements of low sidelobe performance and high resolution. The IGSA algorithm is adopted to optimize the microphone array layout, so that more accurate global optimization, faster convergence speed and better multi-target balance are realized, and particularly, the number of microphones and the hardware cost are remarkably reduced while the sound source localization performance is ensured.

The invention relates to the technical field of radars, in particular to a weather radar distance resolution calibration method and system. The method comprises the following steps: collecting oversampling original baseband I / Q data of a point target in a plurality of continuous pulse periods; determining a pulse signal-to-noise ratio, and screening out effective pulses according to a threshold value; carrying out sub-sampling stage time alignment on the effective pulses based on cross-correlation analysis, and carrying out incoherent averaging on power module values of all the aligned pulses to generate an average pulse power envelope; converting the average pulse power envelope to a logarithm domain, and selecting discrete data points in a main lobe region; according to the discrete data points, a nonlinear least square method is adopted to carry out iterative fitting on the generalized Gaussian mathematical model, and a continuous analytic function describing the pulse envelope is obtained; according to the continuous analytic function, determining a pulse time width when the power is reduced to a peak value of-6dB; and determining the real distance resolution according to the pulse time width. The measurement robustness is improved, and sub-meter calibration precision is achieved.

The invention discloses an archive room full life cycle management system based on a radio frequency identification technology, and relates to the field of archive management, the optimal weight vector of each reader-writer antenna array is obtained through a minimum mean square error algorithm, the transmitting phase and amplitude of each node signal are accurately adjusted according to the optimal weight vector, and in the spatial dimension, the optimal weight vector of each reader-writer antenna array is obtained. Through cooperative control and spatial filtering of beams transmitted by a plurality of distributed reader-writer nodes, beam main lobe energy is converged to a target passive RFID electronic tag, a radiation zero point is formed in the direction of a metal file cabinet, meanwhile, spatial power superposition and directional interference suppression are realized, multipath reflection interference in a metal environment is reduced, and the reliability of the metal file cabinet is improved. The signal-to-noise ratio of the label is fundamentally improved, the response rate of the label is ensured to be improved to 98% or above through a dynamic frequency modulation mechanism, and the problem of signal multipath reflection caused by a metal file cabinet is effectively solved.

The invention discloses a method for realizing elliptic cone scanning by a communication-in-moving antenna. The method comprises the following steps: determining the value of a scanning position point number parameter N; determining the value of the maximum scanning offset angle delta A in the azimuth angle direction and the value of the maximum scanning offset angle delta E in the pitch angle direction; determining values of an expected azimuth angle alpha 0 and an expected pitch angle beta 0 of the current antenna; setting a scanning counter i; when i is less than 4N, calculating a parameter theta i, calculating a scanning offset angle delta i, calculating a scanning track beta i of a pitch angle, and calculating a scanning track alpha i of an azimuth angle; the pitch angle of the antenna is controlled to rotate to a new position beta i, and the azimuth angle of the antenna is controlled to rotate to a new position alpha i; and updating the scanning counter i, i = mod (i + 1, 4N), and returning to execute. The method not only can realize elliptic cone scanning, but also can realize cone scanning, and can effectively solve the problem that the average receiving level is reduced when the communication-in-moving antenna of which the cross section of the beam main lobe is elliptic performs cone scanning.

A method for estimating a time of arrival of a signal transmitted over a wireless channel, includes receiving the signal by a receiving device to produce a received signal; filtering by a filter either the received signal or a code sequence, wherein the filter is designed to produce a correlation output that is near causal; correlating the received signal with the code sequence to create the correlation output that is near causal; wherein near causal means that early side lobes and an early part of a main lobe of the correlation output are sufficiently suppressed in order to substantially reduce an impact of delayed multipath onto a first path component in the received signal, wherein the first path is in an operating region; identifying in the correlation output, an observation window associated with a main lobe in the correlation output; processing the observation window to determine a time of arrival of the first path component in the received signal.

The invention relates to the technical field of seismic exploration, in particular to a method for determining structural parameters and sweep frequency signals of a controllable impact seismic source, which is used for carrying out an indoor physical test of a controllable impact seismic source model machine and ensuring the effectiveness of a design scheme of the controllable impact seismic source. Constructing and verifying a multi-body dynamics numerical model of single impact, performing single variable sensitivity analysis on key structure parameters, and determining an optimal structure parameter combination by taking a frequency domain of output seismic waves as an evaluation index; constructing a multi-impact model, performing a simulation test on the sweep frequency control parameter, and determining an optimal sweep frequency signal parameter based on the main lobe amplitude and the main lobe-side lobe amplitude ratio of the output signal autocorrelation function; through forward modeling and cross-correlation-scattered wave inversion imaging processing, an application method of a controllable impact seismic source is established, and validity is verified. The technical problems that a traditional trial and error method is low in efficiency, main lobe energy of seismic source output signals is dispersed due to an unknown parameter influence mechanism, side lobe interference is large, and the signal-to-noise ratio is low are solved.