45results about "Wave based measurement systems" patented technology

The invention relates to a correction method for updating a DEM (digital elevation model) by the aid of ground based SAR (synthetic aperture radar). The correction method includes computing an amplitude image of the SAR according to received complex-domain echo data of the ground based SAR; extracting corner reflector points of the ground based SAR image; registering the ground based SAR image and an optical image; acquiring ground based SAR image data received by two antenna sensors; respectively correcting phases of the two images; computing coherence of interference patterns of two antennas; unwrapping the phases; computing path difference of corrected slope distance signals and reducing inaccurate measurement errors of base line components B<h> and B<v> of the sensors; completing final elevation calibration work by the aid of ground elevation control points; three-dimensionally superimposing and displaying the ground based SAR image, the optical image and the updated DEM. The correction method has the advantages that approximation is omitted in processing procedures, the optical image and the ground based SAR image can be registered, the DEM can be updated in correction procedures, accordingly, the multi-source data can be precisely corrected, and excellent three-dimensional processing result displaying effects can be realized.

In one embodiment, an ultrasonic diagnostic apparatus includes an image creating unit, an image-creation control unit and a display control unit. The image creating unit creates an ultrasound image from data created by adding a reflected wave signal of an ultrasound wave transmitted to an imaging target portion of a subject by using a reception delay time calculated from a set sound velocity set as a sound velocity in the imaging target portion. The image-creation control unit switches a set sound velocity set at a present moment in a variable range, and controls the image creating unit so as to create a plurality of ultrasound images each using a reception delay time corresponding to each of the set sound velocities to be switched. The display control unit controls display such that the ultrasound images created are displayed on a certain display unit.

The invention discloses a truth value-based roadside sensing system evaluation method, which comprises the steps of establishing a truth value sensing equipment group, and synchronously performing roadside sensing data acquisition with sensing equipment of a roadside sensing system RSS to be tested in a selected test time interval; processing the original data returned by the truth value sensing equipment group, completing target type identification and target track identification, and completing sensing data annotation; generating a truth value based on the labeled data, wherein the truth value data comprises the traffic participant target type, the position, the speed, the acceleration and the track; and in the selected test time interval, comparing the structured sensing data output by the RSS to be tested with the truth value data, and outputting a statistical evaluation result of the sensing performance. The invention also provides a truth value system for the evaluation of the roadside sensing system.

The invention relates to a multibeam depth measuring sonar multi-subarray wave beam sharpening method. The method comprises the following steps: carrying out orthogonal transformation on original signals received by a transducer array to obtain needed parsing signals; by use of a subarray divider, carrying out subarray division on the obtained parsing signals to divide the signals into four subarrays overlapped in space and divide the subarrays into two sub wave beam groups; carrying out routine wave beam formation on each subarray, and respectively carrying out first-order sharpening wave beam formation on a sub wave beam group A formed by the first subarray and the fourth subarray and a sub wave beam group B formed by the second subarray and the third subarray; and taking output generated after sharpening wave beam formation of the sub wave beam group A and the sub wave beam group B as input of next-order sharpening wave beam formation, carrying out a second-order sharpening wave beam formation, and taking output after the second-order sharpening wave beam formation as sharpening multibeam output. According to the invention, a tunnel effect can be inhibited under the condition of a quite small computation amount.

The invention provides a pulse interference signal detection and suppression method. The method comprises the steps of: firstly judging whether there is pulse interference, calculating an interferencesuppression threshold if there is interference, and performing suppression processing on interference with the amplitudes of time domain sampling signals exceeding the threshold. Thus, the method cansuppress interference, reduce the influence of artificial or unintentional pulse interference signals on received signals and provide early warning for relevant apparatuses and products being used inan environment.

The invention discloses a secondary radar digital display system designing device comprising a PC machine and a control panel, wherein a left end of the PC machine is connected with a liquid crystal display screen and a radar data feedback device, the PC machine comprises a receiver, an input end of the receiver is connected with a receiving antenna which is fixed on an output end of a transmitter via a fixed electric cable, a signal processing plate is mounted in the transmitter, multi-stage filter circuits are welded on the signal processing plate, a radio frequency filter is arranged at a primary stage, an output end of the radio frequency filter is connected with a radar power source group, an output end of the radar power source group is connected with a triggering circuit, an output end of the triggering circuit is connected with the receiver, an FPGA controller and an embedded processor are mounted in the control panel, and a communication data port of the FPGA controller is connected with the embedded processor via an RS232 bus; the embedded processor is connected with a data storage device, a data collection card and a serial port communication module.

The invention is a processing method for an m-sequential code pulse modulation ultra wide band radar echo, relating to m-sequential code ultra wide band radar technology, comprising a signal emission scheme which combines an m-sequential code ultra-wide-band radar and a post-processing method; and an m-sequential code ultra wide band radar echo processing method. The method of the invention can effectively improve the problem that a side lobe is relatively high after m-sequential code signal pulse compression, effectively introduce Fast Hadamard Transformation at the same time, and raise an echo processing speed.

The present invention provides a radar antenna protection channel generation method. The method comprises the following steps: Step 1: determining an initialization parameter (wherein the protection channel parameter matrix is an NxM-dimensional matrix equal to the dimension of the antenna array element), and setting the initial value of the parameter matrix; Step 2: determining the objective optimization function according to the characteristics of the radar antenna protection channel; Step 3: using the pattern search algorithm to perform single optimization through the objective optimizationfunction; Step 4: repeating the step 3 operation for M times to obtain a set of M times optimization results; and Step 5: in the set of M times optimization results, finding out an optimization result that can minimize the objective optimization function to generate an antenna protection channel. The protection channel generation parameters obtained by using the method provided by the present invention have correctness, effectiveness and reliability; and the protection channel generated according to the parameters can effectively suppress the side antenna interference and various strong clutter echoes.

The invention discloses an intelligent generation method of range gate pull-off interference, belongs to the technical field of electronic countermeasures and aims to solve the problem that a traditional range gate pull-off interference method ignores information interconnection among multiple frames and is not flexible. The method comprises the following steps of: analyzing a range gate pull-off interference process and establishing a range gate pull-off interference multi-frame optimization model; in order to measure the effect of range gate pull-off interference, selecting an average gate offset distance as a target function; aiming at the challenges that the intermediate state of the target function is unknown and noise is involved, fitting the target function by utilizing a Monte Carlo method; and finally, providing a range gate pull-off interference optimization method based on an improved particle swarm algorithm. The algorithm provided by the invention can dynamically adjust the pull-off distance of different frames, maximizes the range gate pull-off interference effect, and is superior to a traditional method in the aspects of pull-off success rate and pull-off distance.

The invention discloses a radar receiving channel calibration method based on a monopole crossed loop antenna. Aiming at a radar system which takes a monopole crossed loop antenna as a receiving sensor, the rapid calibration of the amplitude and phase response of each receiving channel is completed under the conditions that the hardware structure and the installation mode of the system are not changed and an external signal source is not used. The basic idea of the method is that a closed loop is formed by using a transmitting antenna, a receiving antenna and a radar receiver which are fixed in position, frequency difference simulation delay between transmitting and receiving local oscillator signals is set, and the amplitude-phase response of each receiving channel is calculated through equivalent matched filtering processing; the included angle between the receiving antenna and the transmitting antenna is changed by rotating the receiving antenna, an amplitude-phase response result within the range of 360 degrees is obtained and compared with an ideal value, and finally the inherent amplitude-phase difference of each receiving channel is obtained. The method does not depend on an external auxiliary signal source, does not need to change a radar system, can eliminate the influence of the external environment of the antenna on a measurement result, and is an effective means for detecting the characteristic difference of radar receiving channels.

A method for evaluating a sensor array includes providing software having the sensor array topology, relating array elements to hardware components. Data from the array elements is collected and evaluated to determine operative components. Displays of the determinations are generated allowing a user to diagnose sensor array failures. Other aspects of the invention provide for automatic array failure diagnosis and improvement of sensor array directivity. An additional aspect provides a system for evaluating a sensor array incorporating a computer with a database and a display.

The invention discloses an adaptive compensation device for horizontal imaging field pitch angle of laser radar. The adaptive compensation device comprises: a metal frame; a turntable fixed to the metal frame; a spindle having one end fixed to the turntable through a fixing point and configured to be capable of rotating around the fixing point, wherein the upper portion of the other end of the spindle is configured to hold a laser, and the spindle is used for rotating to adjust imaging field pitch angle of the laser; a thermal expansion rod having the upper end fixed to the metal frame and thelower end abutted to the spindle, wherein a thermal expansion coefficient of the thermal expansion rod is greater than that of the metal frame; a spring having two ends fixed between the lower portion of the other end of the spindle and the metal frame. The metal frame and the thermal expansion rod have a great thermal expansion coefficient difference; upon a temperature change, deformation of the thermal expansion rod may push the spindle so as to drive a laser beam emitted by the laser on the spindle to rotate opposite to a displacement of the pitch angle, and thermo-optic drift due to temperature gradient is adaptively compensated.

The invention discloses a laser radar calibration method and apparatus, an electronic device and a storage medium. The method comprises the steps of obtaining point cloud data of a reference laser radar and a to-be-calibrated laser radar for the same scene; matching the point cloud data acquired by the reference laser radar and the to-be-calibrated laser radar to obtain coordinates of the reference laser radar in a to-be-calibrated laser radar coordinate system; according to the coordinate of the reference laser radar in the coordinate system of the to-be-calibrated laser radar, the absolute coordinate of the reference laser radar in the world coordinate system, the initial installation parameter of the to-be-calibrated laser radar relative to the inertial measurement unit, and the pose of the inertial measurement unit in the world coordinate system when the to-be-calibrated laser radar obtains scene point cloud data; solving optimized installation parameters of the to-be-calibrated laser radar relative to the inertial measurement unit; and calibrating the to-be-calibrated laser radar. According to the method, the rapid calibration of the dynamic laser radar platform is realized under the condition of not depending on manual preset environment feature marks.

The invention relates to the technical field of radars, and in particular relates to a radar turntable north calibration control system with a north calibration function. According to the radar turntable north calibration control system of the invention, an external clock module continuously inputs clock frequency signals to a position counter, a north calibration module, a data communication module, a data storage module and an azimuth pulse output module; the position counter module records an encoder signal input by the encoder according to the clock frequency signal, converts the encoder signal into a position signal and stores the position signal into the data storage module; the azimuth pulse output module outputs a pulse signal according to the position signal recorded by the position counter; and the north calibration module is associated with the data storage module, acquires the current position signal, compares the current position signal with the originally stored positionsignal, and performs north calibration. The radar turntable north-correcting control system is integrated with an existing command system, so that the command system has a north calibration function,the north calibration system does not need to be separately and independently designed, and the delay effect is greatly reduced on the basis of FPGA work.

The invention discloses an m-bit optical delayer and a light-operated phased array multi-beam receiving network, belongs to the technical field of phased arrays, and solves the problems of delay errors and limitation of equal wavelength intervals caused by non-uniformity of optical fiber dispersion coefficients in a dispersion delay mode of a dispersion optical fiber. Time-delay control over multi-wavelength optical carriers is achieved through a cascade optical switch and a multi-wavelength wavelength division multiplexing and demultiplexing technology, and the problems of time-delay errors and limitation of equal-wavelength intervals caused by non-uniformity of optical fiber dispersion coefficients in a dispersion time-delay mode based on dispersion optical fibers are solved. And the delayer has an important application value in a multi-beam light-operated phased array receiving network.

The invention discloses a 4D millimeter wave automobile radar dynamic testing device, and particularly relates to the technical field of automobile radars, the 4D millimeter wave automobile radar dynamic testing device comprises a testing device box, a damping bottom plate is movably arranged at the lower part in the testing device box, and a positioning clamping seat is fixedly arranged at the center position of the bottom of the damping bottom plate; a set of damping springs are fixedly connected to the bottom of the damping bottom plate, a rotary table is fixed to the front end of the top of the damping bottom plate, an arc-shaped support is arranged outside the rotary table, and a mounting frame is fixedly mounted at the front end of the arc-shaped support. A damping spring is arranged at the bottom of a damping bottom plate to achieve good damping performance, when devices in the testing device box need to be adjusted, a threaded rod works and rotates to drive a sliding block to move upwards outside the threaded rod, and a balance sliding rod slides in a balance sliding groove to achieve a balance limiting effect; therefore, the damping bottom plate can be ejected out through the top frame, internal working devices can be conveniently adjusted, and use is convenient.

The invention discloses a rapid scanning microwave detector and a detection method, and the microwave detector employs the same microwave source to transmit signals and carries out the down-conversion of the transmitted signals twice, greatly reduces the phase noise, is simple in structure, does not need a lengthy delay line, does not need the length matching of the delay line and a radio frequency line, and improves the detection efficiency, and rapid detection of different physical quantities such as distance, speed, density and the like can be realized in a specific measurement environment.

The invention discloses a programmable laser scanning track device. The scanning track of a laser radar can be programmed. The device comprises three front surface reflectors, three reflector supports, two integrated stepping motors, two motor fixing supports and a base. The device is characterized in that by utilizing the characteristics of a wide coverage range and ultrahigh reflection efficiency of a reflection wave band of the front reflector and strong stability and high accuracy of rotation of the stepping motor, light beams are deflected in different directions at two positions of 1 and 2; and position points obtained according to a Bresenham algorithm are converted into corresponding pulse signals through an STM32 to control stepping motors at the position 1 and the position 2 respectively, and a laser scanning track is programmed. Different scanning tracks, scanning angles and laser point densities can be selected according to different requirements, the applicable laser wave band is wide, and the scanning precision is high. The scanning device is stable in operation, good in heat dissipation effect and capable of keeping high-precision scanning work for a long time.

The invention provides a method and a device for determining an isolation distance between a 5 GHz-band RLAN station and a radar system, and the method comprises the steps: building a network topology structure of the RLAN station and the radar system according to a real deployment condition, so as to simulate signal interference in a real scene. On the basis of deterministic analysis and Monte Carlo simulation calculation, under the conditions of a preset isolation distance, a preset frequency interval, set RLAN station parameters and radar system parameters, simulation operation is carried out, the interference state of an RLAN station to a radar system is judged, and a proper isolation distance is screened out. Simulation is carried out based on various parameters in real conditions, a simulation result meeting the actual conditions can be obtained, construction and deployment of the RLAN station and the radar system are accurately and efficiently guided, the construction efficiency is improved, and the construction cost is saved.

The invention provides a false color laser radar system. The false color laser radar system comprises a wide-spectrum light receiving and transmitting device, a color separation prism combination, a data acquisition system and a control system which are connected in sequence, wherein a control unit is used for controlling the wide-spectrum light receiving and transmitting device to emit radar beams to a target object for illumination; the wide-spectrum light receiving and transmitting device transmits an echo light signal reflected by the target object to the color separation prism combination; the color separation prism combination divides the echo light signal into a plurality of spectrum channels according to wavelengths; and the control unit further processes and synthesizes the light beams of the plurality of spectrum channels acquired by the data acquisition unit to obtain false color point cloud data. According to the false color laser radar system, the echo light signal is divided into the plurality of spectrum channels according to the wavelength by using the color separation prism combination, the structure is simple, and compared with a hyperspectral light splitting mode with the channel width of 10 nm, the selection channel width of the color separation optical filter is not less than 100 nm, higher light pulse energy in the channel can be received, and the technical advantage of long-distance detection is achieved.