CN101169323A - Method of Measuring Dynamic Angle Measuring Accuracy of TV Theodolite Using Rotating Target Indoor - Google Patents

Abstract

The invention discloses a method for measuring the dynamic angle measurement accuracy of a TV theodolite indoors with a rotating target, belonging to a detection method involved in the technical field of photoelectric measurement. The technical problem to be solved is to provide a method for measuring the dynamic angle measurement accuracy of a TV theodolite with a rotating target indoors. The technical solution is: first, select a rotating target, the rotating target must be equipped with an angle encoder on the rotating shaft of the rotating arm, and the optical system on the rotating arm will form a light cone through rotation, with the apex of the light cone; secondly, the rotating The target is docked with the optical path of the measured TV tracking theodolite to form a measurement system; third, implement the measurement of the dynamic angle measurement accuracy of the TV tracking theodolite; fourth, perform data processing: substitute the value of the target encoder into the coordinate transformation formula to obtain the target Space pointing value, calculate the dynamic angle measurement accuracy of the theodolite according to the Bessel formula. This method solves the detection of the dynamic angle measurement accuracy of the TV theodolite indoors.

Description

Method of Measuring Dynamic Angle Measuring Accuracy of TV Theodolite Using Rotating Target Indoor

1. Technical field

The invention belongs to the technical field of photoelectric measurement and relates to a method for detecting the accuracy of dynamic angle measurement of a TV tracking theodolite indoors with a rotating target.

2. Background technology

TV tracking theodolite is a large-scale photoelectric measuring equipment with automatic tracking and measurement functions using TV measurement technology. It is mainly used for the measurement of the trajectory of aircraft, ships, stars and other moving objects. The dynamic angle measurement accuracy of the TV tracking theodolite refers to the error between the real-time measured target space pointing value and the theoretical value or the true value of the theodolite under the specified angular velocity and angular acceleration motion state, usually expressed by the root mean square error of the space pointing value, applied It is often projected onto the horizontal plane and the vertical plane, which are called the root mean square error of the dynamic azimuth angle and the root mean square error of the dynamic pitch angle, respectively.

The accuracy of dynamic angle measurement is one of the important technical indicators to measure the performance of the TV theodolite. For a long time, the detection of this indicator has been carried out in the field. The data are compared to evaluate the dynamic angle measurement accuracy of the TV tracking theodolite. At present, we haven't found any relevant detection equipment or method that can detect the dynamic angle measurement accuracy of TV tracking theodolite indoors.

3. Contents of the invention

In order to make up for the deficiencies in the prior art, the purpose of the present invention is to establish a method that can detect the dynamic angle measurement accuracy of the TV tracking theodolite indoors, so that the manufacturer of the TV tracking theodolite can monitor the TV indoors before leaving the factory. The dynamic angle measurement accuracy of the tracking theodolite is detected, so that a valuable evaluation can be made on the overall performance of the TV tracking theodolite.

The technical problem to be solved by the invention is to provide a method for measuring the dynamic angle measurement accuracy of a TV theodolite indoors with a rotating target. The technical solution to the technical problem is:

First, choose a suitable rotating target, which must be equipped with an encoder capable of real-time angle measurement on the rotating shaft of the rotating arm, and the optical system on the rotating arm should form a circular light cone through rotation, with a light cone vertex. The structure of the rotating target is shown in Figure 1: it includes a target support frame 1, a motor 2, an encoder 3, a rotating arm 4, a mirror 5, a collimator 6, and a target control cabinet 8. The motor 2 is installed on the target support frame 1, and the shaft of the motor 2 is coaxial with the shaft of the encoder 3 and fixedly connected. Rotating arm 4 is fixed on the rotating shaft of motor 2, and one end of rotating arm 4 is equipped with collimator 6, and the other end is equipped with reflector 5, and the normal line of reflector 5 forms a certain angle with the optical axis of collimator 6. When the motor 2 drives the rotating arm 4 to rotate, the light emitted by the collimator 6 is reflected by the mirror 5 to form a conical space simulation target rotating at a certain angular velocity and angular acceleration;

Secondly, dock the rotating target with the optical path of the measured TV tracking theodolite 7 to form a measurement system, and adjust the intersection point of the TV theodolite’s horizontal axis, vertical axis, and visual axis to coincide with the apex of the target’s rotating light cone. This point is defined as the measurement coordinate Origin O, connect the time system of the target with the time system of the theodolite, so that both have the same absolute time and synchronous sampling signals;

The 3rd, implement the measurement to TV tracking theodolite 7 dynamic angle measuring accuracy: start motor 2, allow motor 2 to drive target rotating arm 4 to rotate, control TV tracking theodolite 7 to automatically track target light cone target, record the azimuth angle, pitch of target in real time Angle and miss amount, and the computer of target control cabinet 8 records the angle value of target encoder 3 simultaneously;

Fourth, data processing: Substituting the recorded value of the target encoder 3 into the formula obtained according to the spherical trigonometry theorem:

E＝arcsin(cosasinb+sinacosbcosθ)

A＝arcsin(sinasintθ/cosE)

In the formula: a is the angle between the target rotation light cone and the rotation axis, b is the angle between the target rotation axis and the horizontal plane, A is the azimuth angle of the theodolite 7, E is the elevation angle of the theodolite 7, and θ is the target encoder 3; (this formula can be found on page 251 of the book "Photoelectric Measurement" published by National Defense Industry Press in October, 2002. This formula is used for the data coordinate transformation between the target and the theodolite. The conversion of the pointing value of the target space, which is the basis for calculating the angle measurement accuracy).

Through the above calculations, the space pointing value of the target is obtained, and this is used as the true value of the space pointing of the target target. The target pointing value measured by the theodolite and the pointing value are aligned with the data based on time, and the dynamic angle measurement of the theodolite is calculated according to the Bessel formula. Accuracy, represented by root mean square error of azimuth angle and root mean square error of pitch angle:

${\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; =</span>\sqrt{\frac{\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}$

${\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; E.</span>}}<span\; class="notranslate">\; =</span>\sqrt{\frac{\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}$

In the formula: σ _A is the azimuth dynamic angle measurement accuracy of the theodolite, σ _E is the theodolite pitch dynamic angle measurement accuracy, n is the total number of data in one cycle, A _i0 is the azimuth pointing value of the target at point i, E _i0 is the target at i The pitch pointing value at the point, A _i ′ is the azimuth angle measured by theodolite at point i, and E _i ′ is the pitch angle measured by theodolite at point i.

Description of working principle: see Figure 2, a is the angle between the target rotating light cone and the rotation axis, b is the angle between the target rotation axis and the horizontal plane, A is the azimuth angle of the theodolite, E is the elevation angle of the theodolite, ω is The rotational angular velocity of the target, t is the time taken for the target to turn from S0 to S1, θ=ωt is the rotational angle of the target encoder, and OR is the rotational axis of the target. According to the spherical trigonometry theorem:

E＝arcsin(cosasinb+sinacosbcosθ)

A＝arcsin(sinasintθ/cosE)

Assuming that the encoder angle of the target at a certain point in space is θ _i , and substituting it into the above formula, the target orientation (A _i0 , E _i0 ) corresponding to the point is obtained. Assuming that the point measured by the theodolite points to (A _i ′, E _i ′), then the dynamic angle measurement accuracy of the theodolite is:

${\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; =</span>\sqrt{\frac{\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}$

${\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; E.</span>}}<span\; class="notranslate">\; =</span>\sqrt{\frac{\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}$

In the formula: σ _A is the azimuth dynamic angle measurement accuracy, σ _E is the pitch dynamic angle measurement accuracy, and n is the total number of data in one cycle.

Positive effects of the present invention: the present invention solves the problem of indoor detection of the dynamic angle measurement accuracy of TV tracking theodolite, and this method is the first in China, and successfully detected the dynamic angle measurement accuracy of multiple TV tracking devices with this method, and the effect is good. It fills a gap in the field of photoelectric measurement and has been recognized by relevant experts.

4. Description of drawings

Figure 1 is a schematic diagram of the connection between the target and the optical path of the TV theodolite.

Figure 2 is a diagram of the transformation relationship between the target and theodolite coordinates.

5. Specific implementation

The present invention is implemented according to the steps proposed in the technical solution. The accuracy of the target encoder can be selected according to the accuracy requirements of the equipment under test. In general, a high-precision 23-bit absolute encoder can be selected; the base of the target should be stable and the rotation arm should be stable, preferably controlled within Within 2″; the target and the device under test should have the same time reference and the same sampling frequency, and a time system terminal can be installed in the target and the device under test respectively, and this problem can be solved through the method of time system synchronization; in order to make the device For stable tracking and high-precision data, the target should have a stable speed control system; the focal length of the collimator of the target can be selected as 1m; the a angle of the target can be selected from 20° to 30°, and the b angle can be selected from 20° to 40°; It should be tested on the same independent ground as the equipment under test.

Claims (1)

1. The method for measuring the dynamic angle measurement accuracy of a TV theodolite with a rotating target indoors is characterized in that at first, a suitable rotating target is selected, and this rotating target must be equipped with an encoder capable of real-time angle measurement on the rotating shaft of the rotating arm , the optical system on the rotating arm is to form a circular light cone with the apex of the light cone through rotation; the structure of the rotating target includes a target support frame (1), a motor (2), an encoder (3), and a rotating arm (4) , reflector (5), collimator (6), target control cabinet (8). The motor (2) is installed on the target support frame (1), and the shaft of the motor (2) is coaxial with the shaft of the encoder (3) and fixedly installed. The rotating arm (4) is fixed on the rotating shaft of the motor (2). One end of the rotating arm (4) is equipped with a collimator (6), and the other end is equipped with a reflector (5). The normal line of the reflector (5) is in line with The optical axes of the collimator (6) form a certain angle. When the motor (2) drives the rotating arm (4) to rotate, the light emitted by the collimator (6) is reflected by the mirror (5) to form a conical space simulation target rotating at a certain angular velocity and angular acceleration; Secondly, the optical path of the rotating target and the measured TV tracking theodolite (7) is docked to form a measurement system, and the intersection point of the horizontal axis, the vertical axis, and the visual axis of the TV theodolite is adjusted to coincide with the apex of the target rotating light cone. This point is defined as Measure the coordinate origin O, connect the time system of the target and the time system of the theodolite, so that the two have the same absolute time and synchronous sampling signals; The 3rd, implement to the measurement of TV tracking theodolite (7) dynamic angle measurement accuracy: start motor (2), allow motor (2) to drive target rotating arm (4) to rotate, control TV tracking theodolite (7) to track target light cone automatically Target, real-time recording of the azimuth angle, pitch angle and miss amount of the target, while the computer of the target control cabinet (8) records the angle value of the target encoder (3); The 4th, carry out data processing: the value of the target encoder (3) of recording is substituted into the formula obtained according to the spherical trigonometry theorem: E＝arcsin(cosasinb+sinacosbcosθ) A＝arcsin(sinasintθ/cosE ) In the formula: a is the angle between the target rotation light cone and the rotation axis, b is the angle between the target rotation axis and the horizontal plane, A is the azimuth angle of the theodolite (7), E is the pitch angle of the theodolite (7), θ Be the angle of target encoder (3); Through the above calculations, the spatial pointing value of the target can be obtained, which is used as the true value of the spatial pointing of the target target, and the target pointing value actually measured by the theodolite and the target pointing value are aligned on the basis of time, and the dynamic angle measurement accuracy of the theodolite is calculated. Expressed by the root mean square error of the azimuth angle and the root mean square error of the pitch angle: ${\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; =</span>\sqrt{\frac{\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}$ ${\mathrm{<span\; class="notranslate">\; \&sigma;</span>}}_{\mathrm{<span\; class="notranslate">\; E.</span>}}<span\; class="notranslate">\; =</span>\sqrt{\frac{\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}^{<span\; class="notranslate">\; \&prime;</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; E.</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; )</span>}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}}$ In the formula: σ _A is the azimuth dynamic angle measurement accuracy of the theodolite, σ _E is the theodolite pitch dynamic angle measurement accuracy, n is the total number of data in one cycle, A _i0 is the azimuth pointing value of the target at point i, E _i0 is the target at i The pitch pointing value at the point, A _i ′ is the azimuth angle measured by theodolite at point i, and E _i ′ is the pitch angle measured by theodolite at point i.

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