CN104199012A - Real-time difference light beam image movement laser radar beacon height calibration method - Google Patents

Abstract

The invention discloses a method for real-time calibration of the height of a differential light column image moving laser radar beacon. Firstly, the height of the laser beacon and the laser imaging are calibrated in real time by using the gating function of the detector and the sharp edge of the laser beacon imaging at the initial detection height of the radar. position relationship; then count the distance between the imaging position of the laser beam at other heights on the focal plane and the sharp edge of the laser imaging at the initial detection height, and use the object-image relationship to calculate the corresponding height of the laser beam at other heights according to the imaging distance. The invention can calibrate the corresponding altitude of the laser beacon in real time, the calibration process does not require cloudy weather and can effectively overcome the influence of instrument shaking on the beacon height calibration.

Description

A kind of method of real-time calibration difference light beam picture motion laser radar beacon height

Technical field

The present invention relates to optical calibrating method field, specifically a kind of method of real-time calibration difference light beam picture motion laser radar beacon height.

Background technology

Difference light beam picture motion radar, with the inclination focal plane laser beam continuous imaging to larger altitude range simultaneously, is measured atmospheric coherence length profile by the laser beam of statistics differing heights in the differential flutter size of detector image-forming.Because the laser beam of differing heights is at focal plane continuous imaging, therefore need to know the height of laser beam and the laser beam image space corresponding relation at detector.How accurately the laser beam height in definite detection altitude range and the relation of image space are key links of difference light beam picture motion lidar measurement atmospheric coherence length profile.The mode of the difference light beam picture motion Radar Calibration beacon height of existing report is, utilizes the height of cloud layer to demarcate the initial elevation angle of receiving telescope under the weather condition that has cloud, then reduces the laser beam of telescope measurement of elevation Beneath Clouds; This scaling method real-time is poor, be limited to weather condition (need to demarcate the telescopical initial elevation angle in the weather condition that has cloud), and require the angle of Emission Lasers bundle and receiving telescope axis relatively stable, be easily subject to instrument to shake the particularly interference of receiving telescope shake.The advantage of difference light beam picture motion radar is to measure in real time turbulent flow profile; Be subject to that external force (mechanical vibration, wind-force etc.) is disturbed and when shake needs to determine in real time the respective heights of laser beam image at instrument.

Summary of the invention

The object of this invention is to provide a kind of method of real-time calibration difference light beam picture motion laser radar beacon height, utilize laser beam to start size time delay of direct impulse laser at the imaging features of focal plane and detector at the object-image relation of focal plane imaging, laser beam, radar system has realized the height of the laser beacon of real-time calibration certain altitude scope, and can effectively overcome instrument and shake the impact on Calibration of Laser beacon height.

In order to achieve the above object, the technical solution adopted in the present invention is:

A method for real-time calibration difference light beam picture motion laser radar beacon height, is characterized in that: comprise the following steps:

(1), utilize the gate control function of detector to determine the initial detection height of radar, carry out the position relationship of real-time calibration beacon height and beacon imaging at the sharpened edge of focal plane imaging in conjunction with initial detection height laser bundle: the height that utilizes the gate control function real-time calibration laser beam of detector, and make the imaging clear-cut margin of laser beam at detector, then utilize the sharpened edge of detector image-forming to determine the beginning image space of laser beam in inclination focal plane, realize initial height and the real-time calibration of corresponding image space surveyed of laser beam;

(2), utilize the relative position of differing heights laser beam at focal plane imaging, determine laser beam respective heights more than initial detection height according to object-image relation: have fixing position coordinates relation according to the laser beam of object-image relation differing heights in the imaging of focal plane, taking starting altitude laser beam at the sharpened edge of detector image-forming as reference point, utilize the distance size of other image spaces and reference point, and be calculated to be the coordinate of image position in conjunction with detector inclination established angle, utilize the coordinate of image space to obtain the beacon respective heights in this position imaging in conjunction with object-image relation, and then obtain the respective heights of atmospheric coherence length.

Advantage of the present invention is:

(1), utilize the gate control function of detector and the sharpened edge of the initial detection height laser of radar beacon imaging to carry out the relation of real-time calibration laser beacon height and laser imaging position; This innovative point can effectively overcome the impact that instrument shake is demarcated beacon height, and calibration process is without the need for the weather of cloud layer.

(2), add up the spacing of other height laser bundles at image space and the initial detection height laser imaging sharpened edge of focal plane, utilize object-image relation to calculate the respective heights of other height laser bundles; This innovative point can real-time calibration laser beacon respective heights.

Brief description of the drawings

Fig. 1 is difference light beam picture motion radar beacon height scaling method schematic diagram.

Fig. 2 is for utilizing object-image relation to demarcate beacon high-level schematic.

Embodiment

A method for real-time calibration difference light beam picture motion laser radar beacon height, comprises the following steps:

(1), utilize the gate control function of detector to determine the initial detection height of radar, carry out the position relationship of real-time calibration beacon height and beacon imaging at the sharpened edge of focal plane imaging in conjunction with initial detection height laser bundle: the height that utilizes the gate control function real-time calibration laser beam of detector, and make the imaging clear-cut margin of laser beam at detector, then utilize the sharpened edge of detector image-forming to determine the beginning image space of laser beam in inclination focal plane, realize initial height and the real-time calibration of corresponding image space surveyed of laser beam;

(2), utilize the relative position of differing heights laser beam at focal plane imaging, determine laser beam respective heights more than initial detection height according to object-image relation: have fixing position coordinates relation according to the laser beam of object-image relation differing heights in the imaging of focal plane, taking starting altitude laser beam at the sharpened edge of detector image-forming as reference point, utilize the distance size of other image spaces and reference point, and be calculated to be the coordinate of image position in conjunction with detector inclination established angle, utilize the coordinate of image space to obtain the beacon respective heights in this position imaging in conjunction with object-image relation, and then obtain the respective heights of atmospheric coherence length.

The schematic diagram of difference light beam picture motion radar real-time calibration beacon height method as shown in Figure 1.Taking laser beam direction straight up as Z axis positive dirction, taking the horizontal line direction of laser transmitting system 1 and receiving system 2 as X-axis positive dirction.The received system 2 of laser that laser transmitting system 1 produces receives, and the laser beam 3 of certain altitude scope is tilt detection face 4 continuous imagings at detector as beacon, and the laser beam height that different image spaces is corresponding is different.The initial detection height 5 of radar system utilizes time delay and the light velocity to calculate by the gate control function of detector; The scaling method that other of radar system are surveyed height 6 is, the gate control function of detector makes laser beacon have sharp keen edge 7 in the imaging of tilt detection face 4, imaging edge 7 is used for determining that laser beam is in the reference position of tilt detection surface imaging, this position and initial 5 position relationships that are used for real-time calibration beacon height and beacon imaging of surveying highly.At real-time calibration after the relation of laser beacon starting altitude 5 and corresponding image space 7, utilize the laser of other height 6 on laser beacon 3 to carry out laser beam the respective heights more than initial detection height of real-time calibration at the image space 8 of inclination focal plane according to object-image relation with the spacing 9 at imaging edge 7.

Utilize the above laser beam of the initial detection height of object-image relation real-time calibration radar respective heights schematic diagram as shown in Figure 2.Laser beam is from height z _{b, 2}start as beacon the inclination focal plane imaging at difference light beam picture motion radar.According to similar triangle theory, certain altitude Z _bbeacon at focal plane imaging position coordinates (x _i, z _i) with the pass of systematic parameter be:

$\frac{\mathrm{\Δ}}{x_I}=\frac{u}{v}---\left(1\right)$

Wherein Δ is emitting-receiving system center distance, x _ifor focal plane imaging position is at the coordinate of X-axis; for object distance, relevant with system spacing with beacon height; for image distance relevant with beacon height with system equivalent focal length.Bring the expression formula of object distance u image distance ν into relational expression (1) and obtain beacon height z _bwith the X-axis coordinate x of beacon at focal plane imaging _irelation:

$x_I=\frac{z_{B}f}{z_B-f}\frac{\mathrm{\Δ}}{\sqrt{z_B^2+{\mathrm{\Δ}}^2}}---\left(2\right)$

In like manner can obtain beacon height z _bwith the Z axis coordinate z of beacon at focal plane imaging _irelation:

$z_I=\frac{z_{B}f}{z_B-f}\frac{z_B}{\sqrt{z_B^2+{\mathrm{\Δ}}^2}}---\left(3\right)$

Therefore, known system parameters f, Δ and beacon are at the position coordinates x of focal plane imaging _ior z _i, can directly calculate the beacon height corresponding with this image space according to relational expression (2) or (3).

The system that transmits and receives in actual radar system has certain spacing (general several meters of spacing), because the mechanical shaking of receiving system causes the beacon of sustained height unfixing in focal plane imaging position.Shake for elimination instrument the image space causing and change the deviation of bringing demarcating beacon height, the present invention utilizes differing heights beacon to determine the height of beacon at the relative position of focal plane imaging.That is: utilize the gate control function of camera to determine the initial detection height z of beacon _{b, 2}, utilize the initial beacon of height of surveying at the sharpened edge p of focal plane imaging ₂coordinate (x _{i, 2}, z _{i, 2}) be reference point, this reference point is used for the image space of real-time calibration certain altitude beacon in focal plane; Utilize other image spaces of focal plane (to claim p ₁point) and this sharpened edge p ₂the spacing d of point _{p1, p2}inclination established angle in conjunction with detector calculates p ₁the position coordinates of point.Circular is:

x _I,1＝x _I,2-d _p1,p2cos(θ) (4)

z _I,1＝z _I,2+d _p1,p2sin(θ) (5)

Wherein d _{p1, p2}for p ₁, p ₂the spacing of point, obtains in conjunction with pixel dimension by the pixel count of 2 image spaces.θ is the inclination established angle of detector, can calculate by systematic parameter, and concrete account form is:

$\mathrm{\θ}={\tan }^{-1}\left[\frac{f}{\mathrm{\Δ}}\right]---\left(6\right)$

Therefore first utilize the pulse delay time to calculate initial detection height z by the gate control function of detector _{b, 2}, then calculate the initial imager coordinate x of height in focal plane that survey according to relational expression (2), (3) _{i, 1}, z _{i, 1}; Calculate other image spaces p of laser beam according to pixel count ₁with reference point p ₂the pel spacing d of point _{p1, p2}, utilize the inclination established angle of relational expression (6) calculating detector, by parameters fully utilize relational expression (4), (5) can calculate the laser beacon height that other image spaces of laser beam are corresponding.This scaling method not only can real-time calibration beacon height and has effectively been overcome instrument shake to directly utilizing object-image relation to calculate the deficiency of beacon height.

Claims (1)

1. A method for real-time calibration of differential beam image motion laser radar beacon height, characterized in that: comprise the following steps: (1) Using the gating function of the detector to determine the initial detection height of the radar, combined with the sharp edge of the initial detection height laser beam imaging on the focal plane to calibrate the positional relationship between the height of the beacon and the imaging of the beacon in real time: use the detector The gating function calibrates the height of the laser beam in real time, uses the sharp edge of the detector to determine the starting imaging position of the laser beam on the inclined focal plane, and realizes the real-time calibration of the starting detection height of the laser beam and the corresponding imaging position; (2) Count the relative positions of the laser beams at different heights on the focal plane, and determine the corresponding height of the laser beam above the initial detection height according to the relationship between the object and the image: according to the relationship between the object and the image, the imaging of the laser beam at different heights on the focal plane has a fixed The positional coordinate relationship of the laser beam at the initial height of the detector is taken as the reference point, and the coordinates of the imaging position are calculated by using the distance between other imaging positions and the reference point, and combining the tilted installation angle of the detector; using the imaging position The coordinates of the coordinates combined with the relationship between the object and the image can be used to obtain the corresponding height of the beacon imaged at this position, and then the corresponding height of the atmospheric coherence length can be obtained.