30 results about "Laser doppler velocimeter" patented technology

The invention discloses a non-intrusive experimental device used for researching underwater bubble plumes. The non-intrusive experimental device comprises a power system, an experimental system and adata collection system; the power system comprises an air compressor and a gas buffer tank which are connected with each other; the experimental system comprises a wave maker, a background plate, a water tank and a steel pipeline arranged at the interior of the water tank; the gas buffer tank is connected with the inlet of the steel pipeline through a gas transportation soft tube, the outlet of the steel pipeline is connected to a gas outlet soft tube and stretches out of the water tank and a leakage hole is formed in the steel pipeline; and the data collection system comprises a high-speed camera and a compact type laser doppler velocimeter. The experimental device can measure upward floating time of the gas, bubble plume dimension and horizontal migration distance, flow and pressure of the gas before after the leakage hole and speed of the gas at any measuring point of the flow field; and the parameters provide verification path for a numerical simulation method and perfect underwater bubble plume theory.

A motion member (1) urged by an application spring (4) is made to collide with a surface of a sheet material supported by a support member (14) so as to be deflectable and deformable. The velocity of the motion member (1) during the collision process is detected every second by a measuring portion (17) of a laser Doppler velocimeter. A control circuit (121) measures the velocity of the motion member (1) immediately before the collision of the motion member (1) with the sheet material, the time period of deflection deformation until the sheet material collides with an opposing member (15), and the time period of compression deformation after the collision of the sheet material with the opposing member (15), and outputs a result thereof as sheet material information to a control portion (120). The timing at which the sheet material collides with the opposing member (15) is detected by an output of a piezoelectric element (16) connected to the opposing member (15).

A double-optical path laser Doppler velocimeter includes a laser source, a light source beam splitter, a photoelectric receive and electronic process system and a focusing system, among which, the laser source, the beam splitter, the photoelectric receive and electronic process display system, a mobile lens and a fixed lens in the focusing system are set on the optical axis of the propagating direction of the laser source beam orderly from left to right to compose a measurement system. The moving direction of the object and the axis of the test system are vertical to the optical axis of the laser ranger, a step motor controller drives the step motor to drive the ballscrew based on the distance of the tested moving object to regulate the distance between the mobile and the fixed lenses to let the laser beam focus drop on the tested moving object accurately.

The invention discloses a LDV / INS (Laser Doppler Velocimeter / Inertial Navigation System) combination-based vehicle-mounted height measurer and a method thereof. The vehicle-mounted height measurer comprises an inertial navigation system, a laser Doppler velocimeter, a signal solving unit and a height information display unit, wherein the inertial navigation system and the laser Doppler velocimeterare arranged on a vehicle; the inertial navigation system is used for measuring a real-time pitch angle of the vehicle in the driving process and transmitting the measured real-time pitch angle information to the signal solving unit; the laser Doppler velocimeter is used for measuring a real-time speed in the vehicle driving process and transmitting the measured real-time speed information to thesignal solving unit; the signal solving unit is used for solving to obtain an elevation height increment of the vehicle in a set unit time interval according to the speed information and the pitch angle information, accumulating all height increments from an initial point to a to-be-measured point, and finally solving the elevation of the to-be-measured point. The vehicle-mounted height measurerdisclosed by the invention has the characteristics of being capable of avoiding influence of meteorological changes, small in influence of atmospheric refraction, high in working efficiency, high in measurement accuracy and the like.

The invention discloses a simulation method of 'wave current-structure-seabed' dynamic coupling experiment. The method utilizes a simulated experimental water tank, sinks the simulated structure on the simulated seabed in the simulated experimental tank, and controls the structure through a sensor. The dynamic load on the object, the dynamic response of key parts, and its dynamic displacement change are detected, and the wave height meter, PIV particle image velocimeter, and Doppler laser velocimeter are set up to measure the wave height and the velocity of the flow field around the structure. The dynamic response of the soil is detected through the pore water pressure sensor and the earth pressure cell, and finally the detection data is collected and processed synchronously through the multi-channel data acquisition system to truly reproduce the actual stress status of the structure . The invention also discloses a simulated experiment water tank. A seabed simulated tank is arranged at the bottom of the simulated experiment tank, and the simulated tank is filled with simulated seabed soil. This method can truly reproduce the actual stress state of the structure.

The invention discloses a tight combination method for calculating a pseudo range / pseudo range rate by using a Doppler velocimeter. The method comprises: step 1, installing a strapdown inertial navigation system, a laser Doppler velocimeter, and a Beidou satellite navigation system at a moving carrier, and electrifying the combined navigation system for starting up; step two, carrying out initial position parameter binding; step three, keeping the moving carrier to be still for five minutes, carrying out initial alignment to obtain an initial attitude angle; step four, starting a tight combination mode and starting the moving carrier; and step five, carrying out calculation to obtain a pseudo range value and a pseudo range rate value, and carrying out tight combination navigation by using differences between the pseudo range value and pseudo range rate value and pseudo range and pseudo range rate values outputted by a Beidou satellite navigation system as observation values of the combined navigation system. According to the invention, tight combination with the Beidou satellite navigation system is carried out by using the pseudo range value and pseudo range rate value calcualtd by the laser Doppler velocimeter and function complementation is realized; and the pseudo range value and pseudo range rate value of the moving carrier are deduced based on the location of the moving carrier and the Beidou satellite, so that high-precision navigation is realized.

The present application relates to an initial alignment method of an inertial navigation system based on a laser Doppler velocimeter. The method includes: in the earth-centered inertial coordinate system and the local navigation coordinate system, based on the speed measurement value of the laser Doppler velocimeter, the specific force equation and the estimation of the cosine matrix of the attitude direction, the alignment process of the strapdown inertial navigation system is established. Process models and measurement models. Construct the state vector with the attitude error of the inertial navigation equipment, the gyroscope zero offset drift, the accelerometer zero offset drift, and the installation angle error and scale coefficient error of the laser Doppler velocimeter as components, and establish a robust square root unscented quaternion estimation device, and get the predicted value of the state vector to carry out the initial alignment of the strapdown inertial navigation system during travel. The process model and measurement model of the above method utilizes the high-precision velocity output of the laser Doppler velocimeter, considers the inertial measurement unit error in the initial alignment, and the installation inclination and scale coefficient of the laser Doppler velocimeter, which can improve the attitude estimation precision.

The invention provides a calibration device and method for a laser Doppler velocimeter based on a lithium niobate modulator. The calibration device and method mainly solve the problem that in the prior art, detection and calibration of the laser Doppler velocimeter in a high speed measurement range are difficult to meet. The calibration device comprises a lithium niobate modulator, a radio frequency signal amplifier, a signal source, an optical fiber isolator, a first optical fiber coupler, a second optical fiber coupler, a third optical fiber coupler and an optical fiber beam expander. According to the device and the method, the standard speed is generated through a Doppler signal simulation method, the measurement precision can be obtained according to the standard speed and the measurement speed, the detected laser Doppler velocimeter is calibrated, and the highest standard speed which can be simulated theoretically exceeds 10km / s.

The invention relates to a motion starting point automatic positioning method applied to a laser Doppler velocimeter. The motion starting point automatic positioning method solves the two defects of atraditional laser Doppler velocimeter: 1, the speed measurement precision in the initial motion stage is low; 2, and a relationship between an absolute moment and a movement speed of a measured object cannot be obtained. The motion starting point automatic positioning method comprises the following steps of (1) data acquisition and (2) calculation of a moment t1 when a measured object starts to move from a static state. The motion starting point automatic positioning method can automatically position to the absolute moment when the measured object starts to move from the static state, is convenient to obtain the relation between the absolute moment and the object movement speed, and improves the speed measurement precision in the initial movement stage.

The invention discloses a particle velocity measurement system of the impact surface and the free surface of a light-transmitting material, which includes a launch device, an impact object, a target plate, a target frame, and an all-fiber laser Doppler velocimeter, and the impact object is controlled by the launch device. The target plate is made of light-transmitting material, the impact surface of the target plate is coated with a total reflection film, the free surface of the target plate is coated with a semi-reflective film, the target plate is fixed on the target frame, and is facing the impact object, so The laser lens of the all-fiber laser Doppler velocimeter is directly arranged on the side of the target plate coated with a semi-reflective film, and is at a certain distance from the semi-reflective film. connected to the main body of the instrument. The invention solves the problem that the existing flat plate impact experiment device cannot accurately measure the particle velocity of the free surface of the target plate, and cannot simultaneously measure the particle velocity of the impact surface of the target plate, and has the advantages of accurate measurement results, high precision, and less susceptible to environmental interference The advantages.

The invention relates to an eye movement tracking device (20) comprising: a camera (2) configured to take an image of an eye (10) at a first scan rate; a laser velocimeter (3) configured to capture an eye velocity of the movement of the eye (10) at a second scanning rate by means of a laser Doppler velocimeter; and a control device (4) configured to determine an absolute eye position based on the image and to track a gaze direction of the eye (10) based on the absolute eye position and the eye speed.

A vehicle laser Doppler velocimeter based on a scanning galvanometer comprises a reference beam type laser Doppler velocity measurement probe, a coaxial cable, a signal processing unit and a display screen, and a scanning galvanometer is arranged on a laser path before a laser of the reference beam type laser Doppler velocity measurement probe is incident to the ground. The scanning galvanometer is provided with a first working position and a second working position. When the scanning galvanometer is located at the first working position, the laser of the reference beam type laser Doppler velocity measurement probe is directly incident to the ground; and when the scanning galvanometer is located at the second working position, the laser of the reference beam type laser Doppler velocity measurement probe is incident onto the scanning galvanometer, the laser reflected by the scanning galvanometer is incident to the ground. According to two Doppler frequencies measured when the scanning galvanometer is rotated to the first working position and the second working position, the variation of the emission inclination angle can be calculated to obtain the motion speed of the vehicle and eliminate the influence of the emission inclination angle variation on the velocity measurement precision when the vehicle is bumped.