SU1364873A1 - Measuring head of hydrostatic geodetic level - Google Patents

Abstract

The invention relates to geodetic instrumentation and allowed Hydrostatic, 1976, to increase the sensitivity of the device. A diffraction grating 3 is placed between the beam forming unit 2 and the measuring vessel 4 filled with the working fluid. Fourier energy spectrum, the lattice defining structure. On the screen of the indicator 9, the electrical signal converted by the photoreceiver 7 forms the value of the working fluid level. An expression is given to determine the distance between the diaphragm 6 and the photodetector 7. I il. (L

Description

5 6 7 & 9

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The invention relates to a geodetic instrument making, in particular to devices for hydrostatic leveling.

The purpose of the invention is to increase the sensitivity of the device.

The drawing shows a diagram of the device.

The device consists of a light source I, a light beam forming unit 2, a diffraction grating 3, a measuring vessel 4, a lens 5, a diaphragm 6, a photodetector 7, a gain and conversion unit 8, and an indicator 9. The device operates as follows.

Narrow beam of coherent light

Noah with a flat front is determined by

t4 f d f (x).

As an analyzer of the optical signal in the device, it is proposed to use a circular diaphragm 6 that plays the role of a spatial filter and cuts off all the spatial frequencies of the Fourier energy spectrum, except the fundamental frequency (x), which determines the lattice structure. Directly near the diaphragm

there is a photodetector 7, which converts the luminous flux into an proportional electric signal, which is amplified and converted (for example, into digital form) in the block

from the source I enters the block 2 of the form-20 8 amplification and conversion of the signal, the peace of the light beam, is complete and is fed to the input of the indicatra 9,

for example, in the form of a collimator, necessary for the formation of a beam of monochromatic waves with a plane front. Formed wave front, passage through the diffraction grating

3, translucent measuring vessel

4, filled with the working fluid, the level of which must be measured.

the screen of which forms the value of the measured non-value of the level of the working fluid. In carrying out the measurement, the property of diffraction grating 3 is used to diffract into the first (or some other) order the amount of light energy proportional to the number of open (above the level of

The coherent wave front of the diffraction is 30 liquid) lattice elements.

em on the elements of the diffraction grating the formula of the invention

4 and assembled by lens 5 to form

in the plane conjugated to the source. The measuring head of a hydrostatic level, containing successively located a source of communication, a light beam forming unit, a measuring vessel, an objective lens, a photoreceiver, a signal amplification and conversion unit, and an indicator that sensitivity, it is equipped with a diffraction grating located between the beam forming unit and the vessel, the source of light. It is coherent, and the diaphragm is set in front of the photodetector at a distance ti from the optical axis defined by the expression

radiation distribution, described by the Fourier transform

+ / (P

EU t

Akf, J

-L / i

-i (xlx S. X e dx,

Cx)

40

)

de E - illumination on the reference

lattice; L is the coherent wavelength

radiation;

f. —focal distance of the Fourier lens;

And - the size of the input window; f (x) - spatial frequency

lattice f where d (x)

lattice period;

S (x) is the density distribution function along the X coordinate axis of the lattice.

Coordinate of the first spectral maximum for cases of volvniipi lighting Order 6578/32 Circulation 680

What up to that? ta sera

50

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the screen of which forms the value of the measured non-value of the level of the working fluid. In carrying out the measurement, the property of the diffraction grating 3 is used to diffract into the first (or some other) order the amount of light energy proportional to the number of open (above the level of

The measuring head of a hydrostatic level, containing successively located a light source, a light beam forming unit, a measuring vessel, an objective lens, a photodetector, a signal amplification and conversion unit, and an indicator that, in order to increase sensitivity, it is equipped with a diffraction grating located between the beam-forming unit and the vessel, the light source is coherent, and the diaphragm is set in front of the photoreceiver at a distance ti from the optical axis, which is expressed by eat

1 - f (x) - f,

A - spectral characteristic

light source; f d - focal length of the lens;

f (x) is the spatial frequency of the lattice.

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Claims (1)

Claim The hydrostatic measuring head is 35 e dx, a level containing a sequentially located light source, a light beam forming unit, a measuring vessel, a lens, a photodetector, an amplification unit and a pre-eminence Е _о on the reference ^f A + A / 2 ^Е (хГ Akf \ ^S 6d ^x - illumination of the grill; - wavelength of coherent radiation; - focal length of the Fourier lens; - size of the input window; signal generation and an indicator, about m- _40, characterized in that, in order to increase sensitivity, it is equipped with a diffraction grating located between the forming unit χ f (x) is the spatial frequency of the grating f * = j, where d (x) is the grating period; S (x) is the density distribution function along the coordinate axis X of the lattice. The coordinate of the first spectral maximum for the case of illumination of the beam wave and the vessel, the source of light ₄₅ is made coherent, and the diaphragm is installed in front of the photodetector at a distance η_ from the optical axis, defined by the expression 1 - A 'f (x) · f ^, where A is the spectral characteristic of the light source; f d - the focal length of the lens; f (x) is the spatial frequency of the lattice. VNIIIPI Order 6578/32 Circulation 680 Subscription Custom polygr. ave, city of Uzhhorod, st. Project, 4