554 results about "Radar measurement" patented technology

The invention provides an early warning method for preventing vehicle collision and a device. The method includes steps of acquiring video image information of the front of a vehicle, and obtaining first characteristic information of an obstacle target of the front of the vehicle according to the video image information; acquiring radar measurement information of the front of the vehicle, and determining second characteristic information of the obstacle target of the front of the vehicle according to the radar measurement information; fusing characteristics of the first characteristic information and the second characteristic information so as to determine final characteristic information of the obstacle target of the front of the vehicle; estimating collision risks to the obstacle target according to the final characteristic information, and realizing early warning for a driver according to a collision risk estimation result. The obstacle target of the front of the vehicle and state information of the obstacle target are identified by means of fusing information, which are acquired by double cameras and a radar device, of the front of the vehicle, target identification precision is improved, and a collision preventive alarm function of the vehicle can be well realized.

The invention discloses a laser radar road reconstruction and expansion exploratory survey design method. The method comprises the steps of A designing a result coordinate benchmark, measuring basic control and measuring pavement control points; B determining parameters including the data density, acquisition route and the like, and acquiring vehicle laser radar data along a main road and a ramp; C determining parameters including the data density, flight design and the like, and acquiring airborne laser radar data according to a designed flight strip; D realizing laser radar data fusion by refining laser point cloud plane coordinates and elevation coordinates and refining track line data; E acquiring characteristics of road traffic lane lines by using point cloud intensity information, and realizing extraction of characteristic lines of road pavements, protection and the like by adopting a method of projecting three-dimensional point clouds to a two-dimensional plane; F recovering planar elements and longitudinal surface elements of an existing road; G producing a DEM (digital elevation model), a DOM (digital orthophoto map) and a DLG (digital line graphic); H collaboratively designing laser radar measurement and road reconstruction and expansion CAD (computer-aided design), designing flat, longitudinal and transverse cross sections of a road, comparing and selecting schemes, and outputting final design drawings and charts.

An integrated rainfall calculation method using X-band dual-polarimetric radar measurement data includes a precipitation classification step of classifying hydrometeors into four types of snow, rain / snow, rain and non-meteorological target through a fuzzy logic technique using a correlation coefficient (cross correlation coefficient, ρhv), features of a measured differential propagation phase (Ψdp(r)) or differential propagation phase (φdp) and a signal-to-noise ratio (SNR) as input variables (input feature vector); a specific differential phase calculation step of separately calculating a specific differential phase by applying a specific differential phase using a total difference of differential phase and signal-attenuation corrected reflectivity for the rain among the classified hydrometeors and applying a specific differential phase calculated using a filtering method for the other hydrometeors; and a rainfall calculation step of calculating rainfall by using a relation between the specific differential phase and the rainfall and using the separately calculated specific differential phase.

The invention belongs to the technical field of multi-radar networking plot fusion, and particularly relates to a multi-radar plot fusion method. The method comprises the following steps of 1, receiving multiple pieces of radar measurement data, conducting space alignment and setting a uniform measurement coordinate system; 2, judging whether the radar measurement data all contains target Doppler velocity information or not, if yes, executing the step 3, and otherwise, executing the step 6; 3, conducting time alignment; 4, conducting plot association and plot fusion to obtain fused plot information; 5, conducting track association with a formed track and filtering updating by utilizing the fused plot information, and executing the step 7; 6, sorting the data by time, and conducting track association with the formed track and filtering updating in sequence by utilizing the sorted data; 7, conducting track initiation by utilizing the radar data which does not participate in track association; 8, outputting a track result. The multi-radar plot fusion method is beneficial to prolonging the target detection distance and improving the tracking precision and the maneuvering target tracking performance.

The invention provides a rapid extraction and reconstruction method for a data power line of an airborne LIDAR. The method comprises the following steps of: acquiring a large amount of laser point cloud data by using an airborne laser radar measurement system, and filtering the laser point cloud data by properly setting an elevation threshold value to reject point cloud data not formed by a power line; after the filtration of the point cloud data is finished, rejecting a pylon according to the variation characteristics of point cloud density on the two sides of the pylon; counting the point number of each layer of power line in the point cloud data of the power line by adopting a histogram counting analysis method, layering the power line, and fitting the power line in the same layer, thereby separating point cloud data on a single power line; and fitting the power lines by utilizing a catenary equation, estimating a catenary equation parameter, and finally realizing the vectorization of the power line. By the method, automatic power line extraction and pylon extraction between a plurality of spans can be rapidly realized, and extraction efficiency is high; and the method can be used for the transmission line safety inspection of a power sector, and transmission line inspection efficiency is greatly improved.

The invention provides a three-dimensional visual processing method of an extra high voltage transmission line, which comprises the following steps: synchronously acquiring laser point cloud data and digital image data along a transmission line corridor through an airborne laser radar measurement system, and carrying out three-dimensional visual processing and professional analysis in combination of line design parameters and operating parameters after data processing and three-dimensional modeling so as to provide an efficient means for the maintenance and the management of the transmission line of an electric power enterprise. The invention further provides a three-dimensional visual processing system for the extra high voltage transmission line, which comprises a three-dimensional data generation module and a three-dimensional data visual operation module, wherein the three-dimensional data generation module is used for receiving digital image data and laser point cloud data obtained by the laser radar measurement system and generating the three-dimensional scene of the transmission line corridor; and the three-dimensional data visual operation module is used for carrying out three-dimensional visual operation on the three-dimensional data of the transmission line corridor.

The invention discloses a power channel corridor routing-inspection method based on a tilt photography three-dimensional reconstruction technology, wherein the method includes the steps: A, combining a laser radar data measurement technology and a tilt photography technology, and rapidly constructing power transmission line channel high-precision three-dimensional base map data by using the laser radar measurement technology; B, acquiring three-dimensional real scene data of a channel corridor by using the tilt photography measurement technology; and C, carrying out fused analysis of the three-dimensional real scene information and a laser radar channel base map, effectively identifying and extracting trees and obstacles in the channel corridor, and then generating a tree barrier assessment report. By using the method, qualitative analysis of the tree barrier can be effectively turned into quantitative analysis, the position of a to-be-felled tree in the channel can be calculated, the felling area is statistical, and thus the safe operation of the line corridor is ensured.

A method and a system for radar-based gauging of a filling level of a filling material is disclosed, wherein the tank has at least one interfering structure. The method comprises: transmitting at a first time moment a microwave signal towards the surface of the filling material; receiving microwave signals as reflected against the surface of the filling material and as reflected against said at least one interfering structure; calculating based on propagation times of the transmitted and reflected microwave signals at least two distances to reflective surfaces in the tank; and repeating at a second time moment the transmitting, the detecting and the calculating, wherein said first time moment is timely separated from said second time moment. Based on the several repeated measurements, the distance to the surface of the filling material is determiend as the calculated distance that exhibits the greatest change between said first and second time moments. Based on this time difference analysis, it is possible to discinguish moving surfaces very easy and acurate. The method is specifically advantageous in overfill or high level alarm systems.

The invention discloses a method for calibrating external parameters based on a camera and a three-dimensional laser radar, which comprises the following steps: according to a covariance of measurement errors in the perpendicular line direction from a three-dimensional laser radar coordinate system origin to different position target planes and a covariance of measurement errors in a conversion relationship from a three-dimensional laser radar coordinate system to a camera coordinate system in the perpendicular line direction, acquiring an equation of a quadratic sum of the variance including the variance of the camera measurement noise and the variance of the three-dimensional laser radar measurement noise in the covariance of the measurement errors in the conversion relationship; and calibrating a rotation matrix with maximum likelihood estimate by using the reciprocal of the quadratic sum of the variances of all obtained measurement noise as a weighting coefficient. The invention also discloses a system for calibrating the external parameters based on the camera and the three-dimensional laser radar at the same time. The effect of the measurement errors on the rotation matrix to be calibrated is taken into consideration during calibrating, and the algorithm of the maximum likelihood estimate is adopted for the measurement errors in the calibrated result of the rotation matrix, so the calibrating result is more accurate.

Radar apparatus and methods of use thereof for imaging and / or spectrometric analysis. The invention employs pulsed radar signals for magnifying, imaging, scale measuring, identifying and / or typecasting the composition of substances by radargrammetric imaging and / or statistical analysis of energy / frequency spectrums. The invention may be used to locate and / or distinguish a substance from other substances, to image a substance / feature and to monitor the movement of an imaged substance / feature. The systems and methods can be adapted for a variety of applications at a wide range of scales and distances, from large scale, long range applications such as geophysical imaging / analysis, to the small scale such as material typecasting applications and small scale (including microscopic) imaging / analysis, including biological and medical imaging and diagnostic applications. The invention includes novel antenna assemblies and novel data processing techniques.

An object measurement method and system including an arrangement of individual signal transceivers connected together as a flexible unit. The arrangement of individual signal transceivers measures a characteristic of an object situated within a subject.

The invention discloses a target movement situation information data association strategy-based target tracking method. The method includes the following steps that: step 1, the track of a target to be selected is created; step 2, tracking processing is carried out on the track of the target to be selected, a reasonable track of a formal target is established according to a target starting condition; and step 3, a Kalman filtering model is used to carry out filtering estimation processing on the tracks of a tracked target and the formal target, so that a track state estimation value can be obtained, the time to closest point of approach (TCPA) of the tracked target and the formal target is calculated according to a ship collision avoidance radar measurement model and a TCPA value is compared with a target separation time threshold, a target approach time threshold and a target overlap time threshold, so that the movement state information of the targets can be obtained; and step 4, and the association strategy and associated algorithm of the trace points and tracks of the tracked target are determined according to the movement state information of the targets, and the association relation of the tracked target and the trace points can be obtained.

A method of measuring the speed of a vehicle wherein the speed and the distance of the vehicle from a radar system and / or the measuring angle of the vehicle relative to the radar axis is determined by means of a radar measurement so as to characterize or determine the vehicle lane of the vehicle by means of the distance and / or the measuring angle. Knowledge of the vehicle lane makes it possible to unequivocally identify the detected vehicle in a group of vehicles unequivocally.

The invention provides a method and system for laser-IMU external parameter calibration. The method comprises steps of acquiring IMU measurement data and laser radar measurement data; carrying out IMUpre-integration of the obtained IMU measurement data, carrying out calculation to obtain an IMU pose transformation estimated value of the IMU relative to the IMU initial pose at the next moment, andaccording to the estimated value and an actual measurement value of the IMU at the next moment, obtaining an associated residual error associated with the data; processing measurement data of the laser radar, utilizing IMU pre-integration to obtain projection coordinates of reprojecting a plurality of laser radar points to a world coordinate system, and calculating a reprojection error from eachlaser radar point to a calibration target map; adopting a nonlinear least square method to iteratively optimize laser radar-IMU external parameter calibration so that the external parameter calibration result can be obtained. The method is advantaged in problems that in laser-IMU external parameter calibration, mechanical external parameters are not easy to obtain, manual measurement errors are large, and measurement is troublesome are solved, defects of the laser radar and the IMU are mutually overcome to a certain extent, and pose solving precision and the speed of the SLAM method can be improved.

The invention provides a dam slope deformation monitoring system and method. According to the monitoring system, an unmanned aerial vehicle photogrammetry system is utilized to monitor dams in the whole reservoir area, and an encrypted monitoring area with large deformation quantity and large digital elevation difference (a steep slope) is determined; in the encrypted monitoring area, a ground-based interferometric radar measurement system is utilized to determine a first level key area with larger deformation quantity; in the first level key area, a ground-based three-dimensional laser radarsystem is adopted to select a second level key area with larger deformation quantity, a global navigation satellite system (GNSS) is adopted in the second level key area to determine a key monitoringparticle with high deformation speed, and a micro core pile is utilized to monitor and forewarn the collapse process of the key monitoring particle area. According to the dam slope deformation monitoring system and method, precise positioning of the collapse position of the dams in the whole reservoir area and integrated monitoring and early warning of space, air and ground are achieved through time seamless monitoring from slow to fast to the instant of collapse and full coverage monitoring from large area to small area to particle and from two-dimensional to three-dimensional space variation.

A MIMO FMCW radar sensor and a MIMO time multiplexing method for localizing a radar target, in which an FMCW radar measurement is performed with a transmitted signal whose modulation pattern encompasses, for different transmission switching states that differ in terms of the selection of antenna elements used for transmission, mutually temporally interleaved sequences of ramps; ambiguous values for the relative velocity of the radar target are determined from a position of a peak in a two-dimensional spectrum; phase relationships between spectral values of spectra are checked for agreement with phase relationships expected for several of the determined values of the relative velocity; on the basis thereof, an estimated value for the relative velocity of the radar target is selected from the determined periodic values of the relative velocity; and the angle of the radar target is determined on the basis of amplitudes and / or phase relationships between obtained baseband signals.

The invention discloses a target track prediction method based on the cycle neural network, belongs to the radar target tracking field and mainly solves problems of simple model, low complexity, pooruniversality and learning incapability existing in a track prediction method in the prior art. The method comprises steps that firstly, the same type of radar measurement traces and tracking track data in various scenarios are collected, cooperative target track is collected through employing cooperative target information receiving equipment, and the data is eliminated and corrected to form an original track data set; secondly, the target track prediction cycle neural network is constructed, a training sample characteristic vector is set, and a track training set is generated; and lastly, based on a cooperative track training set and a radar track training set, the target track prediction cycle neural network is trained and optimized, and a target track prediction method matched with a radar is generated. The method is advantaged in that the prediction algorithm is generated through automatic training, the application scope is wide, adaptation scenes are a lot, and the practical effect is good.

A synchronous range / velocity measurement system based on a non-scanning laser radar and a CCD camera is disclosed. The invention relates to the field of laser radar measurement and solves the problem that the current non-scanning laser radar can only obtain range information of an object, but is incapable of obtaining motion information. The non-scanning laser radar in the inventive system is composed of two parts including transmission and reception, the transmission part comprises a pulse laser and a transmission optical shaping system, and the reception system comprises an ICCD imager and a reception optical system; in the inventive system, the CCD camera is also combined and shares the reception optical system with the non-scanning laser radar, and a band elimination filter is added in front of the CCD camera so as to receive light signals; on condition that the increased complexity of the system structure is avoided as much as possible, the range information and the motion information of motion objects are synchronously obtained in a very short exposure time; the system is mainly applied to the measurement of the motion objects.

The invention provides a view-variable three-dimensional reconstruction device based on laser radar swinging. The view-variable three-dimensional reconstruction device comprises a laser radar swinging mechanism, a mechanism movement control module and a three-dimensional point cloud reconstruction module, wherein the laser radar swinging mechanism comprises a single-line laser radar, a laser radar center fixing mechanism and a laser radar swinging control mechanism, the single-line laser radar is three-dimensional point cloud data collecting equipment, the laser radar center fixing mechanism bears the weight of the laser radar and fixes the center of the laser radar, and the laser radar swinging control mechanism achieves regulation of the view range of the laser radar and drives the laser radar to swing in an omni-directional manner; the mechanism movement control module controls the movements of the laser radar swinging mechanism and measures the pose of the laser radar in real time; the three-dimensional point cloud reconstruction module splice multiple frames of laser radar measuring data to reconstruct spatial three-dimensional point cloud. The view-variable three-dimensional reconstruction device has the advantages that measuring and reconstruction of a three-dimensional environment can be completed, the view range and point cloud distribution can be regulated according to needs so as to emphasized measuring of the space information of different positions, and the device is high in precision, high in reliability and good in adaptability.

The invention relates to a plant leaf area index measurement method based on the laser radar point cloud technology. Compared with the prior art, the defects that the leaf area index measurement efficiency is low, and the environment requirement is high are overcome. The method comprises the following steps of obtaining three-dimensional laser point cloud data of a plant canopy, cutting the point cloud data, conducting point cloud picture classification inside the plant edge contour, calculating the half side plant volume Vhalf of each plant, counting the number of hit points, counting the proportion of breaking points, and utilizing inversion for working out leaf area indexes. According to the plant leaf area index measurement method, by means of the three-dimensional point cloud data generated through a ground laser radar measurement system, with the combination of the computer graphics technology, the leaf area indexes are obtained from point cloud pictures for calculating needed relevant parameters and conducting multiple linear regression treatment, and therefore the leaf area indexes are calculated.

The invention relates to a measuring device for accurate correction by FMCW radar distance measurement and a compensation correction method, which belong to the technical field of FMCW radar measurement. The measuring device is characterized by comprising an echo signal processing module (1), a peak value extracting module (2), a high-precision phase difference compensation module (3), a frequencydistance conversion module (4) and a display module (5), wherein the echo signal processing module (1) is used for receiving high-frequency echo signals; high-frequency transmission signals are processed by mixing frequency to obtain intermediate frequency signals of 0 kHz to 200 kHz; a threshold valve curve is set for removing disturbance and filtering other signals; frequency domain peak valuesignals are locked; a signal processing unit of a DSP is used for recording all data and storing the data in a data storage unit; the DSP is used for extracting recording signals; the improved high-precision phase difference compensation of the data is carried out and frequency is converted into distance and displayed on the modules (4) and (5). The invention reserves the advantage of a traditional phase difference method and enhances the computing precision of frequency spectrum on the premise of averagely adding 25% of computing quantity.

The invention discloses an automatic calibration method and device of laser radar parameters and a laser radar. The method comprises the steps of (10) setting a first marker with a first marking point in a calibration field, using the laser radar to carry out laser scanning on the calibration field and obtaining scanning data, (20) fitting the scanning data of a position where the first marker is located, and obtaining the fitting space coordinate of the first marking point, and (30) calculating the laser radar parameters by using an error between the fitting space coordinate and the measurement space coordinate of the first marking point, and carrying out the automatic calibration by using the calculated laser radar parameters. According to the method, device and the laser radar, the fully automatic high precision calibration of the laser radar is realized, the density requirement of a laser point is low, the integrity requirement of marker scanning is low, and the automatic precision inspection and evaluation of calibrated laser radar measurement precision can be carried out.

The invention relates to a passive cooperative localization method for a radiation source target at sea according to observed values of double-station radars under the condition of the beyond visual range base line. Aiming at the problem that as under the influence from the earth curvature under the condition of the beyond visual range base line, the base line between the double-station radars is lengthened and angle measurement errors are introduced, the localization precision is poor, the passive cooperative localization method applicable to the beyond visual range base line is adopted to amend the radar measurement errors introduced by the earth curvature to achieve localization. The method comprises the specific steps that (1), coordinates of radar stations 1 and 2 are converted; (2), the detection range of a virtual target is generated initially; (3), the position offset of the virtual target relative to the station 1 is calculated; (4), the coordinates of the virtual target are calculated; (5), the observed value of the virtual target by the station 2 is calculated; (6), the measurement errors are judged; (7), the detection range of the virtual target is updated; (8), a localization result is output. By means of the method, the radar measurement errors introduced by the earth curvature can be amended, and the precision of the radar beyond visual range base line passive cooperative localization is improved effectively.

The invention discloses a method for measuring a target azimuth by single-beam mechanical scanning radar, which relates to the technical field of radar and communication and solves the problems of low angle measurement precision and large operation amount of the conventional single-beam mechanical scanning radar. The method comprises the following steps of: acquiring echo signals by using the single-beam mechanical scanning radar, then performing phase coherence accumulation on the acquired echo signals to acquire a higher signal detection signal-to-noise ratio, taking an azimuth interval of any two echo pulses of a main lobe width of a radar antenna as two beams required for measuring an angle by the single-pulse technology after target information is detected, then calculating two-dimensional images, sum signal intensity and difference signal intensity of a target on two azimuths, and further calculating a sum-to-difference ratio k so as to acquire a target error deflection angle delta theta, wherein the target azimuth theta T is equal to theta i + theta k + delta theta. The method is suitable for radar angle measurement.

The invention relates to the field of communication. The embodiment of the invention discloses a fuzzy processing method of a high-precision ranging radar based on a modulation pulse sequence. The method comprises a resolution determining method of a frequency conversion probe sequence with variable impulse width, a fuzzy problem processing method in a radar impulse sequence, a multipath interference eliminating method in a ranging radar receiver, a non-fuzzy high-precision positioning process of an adjustable variable pulse sequence and a superheterodyne receiving system with high-precision fuzzy eliminating. Non-fuzzy high-precision positioning with long distance can be completed by adjusting the detecting sequence of radar signal and upgrading a signal processing software of the radar receiver according to the method of the invention, the signal processing software of the prior system is easy to be updated, the expansibility is better, and the cost is relatively low. The invention can solve the contradiction of fuzzy distance measured by the radar and target detection resolution, and provides the complete implementation process for measuring the adjustable variable pulse sequence at the same time.

In one embodiment, the disclosure relates to a method for estimating and predicting a target emitter's kinematics, the method including the steps of: (a) passively sampling, at a first sampling rate, an emitter signal to obtain at least one passively measured signal attribute for estimating the target kinematics; (b) inputting the passively measured signal attribute to an estimator at a first sampling rate; (c) determining a radar duty cycle for active radar measurements as a multiple of the first sampling rate, the multiple defining a duration between radar transmissions; (d) directing a radar system to make active target measurements at the determined duty cycle; (e) inputting to the estimator the active target measurements at the determined duty cycle, while continuously inputting the passively measured signal attributes.

The invention discloses a target tracking method based on measurement conversion Kalman filtering state fusion, which belongs to the field of radar target tracking, and particularly relates to a statistical property calculation method utilizing Doppler radar measurement conversion errors. The state fusion target tracking method comprises the steps of: calculating statistical properties of converted measurement errors based on a predicted value measurement conversion method, regarding a position predicted value in a rectangular coordinate system as a condition to obtain a mean value and a covariance of the converted measurement errors, and eliminating correlation between the covariance of the converted measurement errors and measurement errors; and then performing state estimation on a position and Doppler measurement, and finally using a least mean square error criterion to fuse estimation results of the position and Doppler measurement, so as to obtain a final state estimation. The tracking method can be further extended to CV and CA motion models of a 3D radar.

The invention relates to a MIMO-FMCW radar sensor and to a MIMO-time-division multiplexing method for locating a radar target (18), wherein a FMCW radar measurement is carried out using a transmission signal, of which the modulation patterns for different transmission switching states (m), which differ in the selection of antenna elements (12) used for transmitting, comprise time-interleaved sequences (22; 26; 32; 36) of ramps (24; 28; 34; 38); ambiguous values for the relative speed (v) of the radar target (18) are determined from a position (k, l) of a peak in a two-dimensional spectrum (56); phase relationships between spectral values of spectra (X) are checked for conformity with the phase relationships (a (v,m)) expected for a plurality of the determined values of the relative speed (v); based on said phase relationships, from the determined periodic values of the relative speed (v), an estimated value for the relative speed (v) of the radar target (18) is selected; and based on amplitudes and / or phase relationships between obtained base band signals (b), the angle of the radar target (18) is determined.

The present invention relates to the radar measurement technology field, especially to a remote scanning laser radar measurement error correction method. The method comprises: the step S1, establishing a measurement model, and obtaining the position relation of a tested point and an origin of coordinates; the step S2, obtaining the real position relation of the tested point and the laser radar, and establishing the error model of three error sources; the step S3, performing the fractal parameter measurement experiment of the laser radar, and obtaining large sample data of the three error sources; the step S4, employing the statistical method to analyze the probability density distribution of the three error sources, and obtaining the error correction samples of the three error sources in the three-dimensional coordinate system; the step S5, obtaining the three-dimensional coordinate sample according to the error correction samples of the three error sources and the measurement model in the step S1; and the step S6, performing real-time correction of the three-dimensional coordinate measurement point according to the measurement point position corresponding to different objects, the error correction samples of the three error sources and the measured three-dimensional coordinate samples.