The way to resolve the ambiguity in the measurement of the film thickness of the oil spilled on the water surface

 

The invention relates to remote passive ways of measuring the film thickness of the oil, including crude oil itself, and can be used to resolve ambiguities in the measurement of film thickness in the millimeter wavelength range. The invention consists in the fact that the same frequency is measured vertically polarized components of the electric field in noise unpolarized radiation of the sky at two angles of measure1 and2, which set the direction to the Zenith, and the angle values are set with the condition1<2, each of the angles is not equal to the Brewster angle for the measured oil, then sent serially measuring angles1 and2, are installed from the normal to the film surface in the direction of the film, and is measured alternately at every angle sum of coherent waves mirror and respectively penetrates vertical polarization components, taking into account the phase difference caused by the difference in behavior of these components to the input of the meter is proportional to twice the film thickness of the oil, Didelot for a given algorithm based on comparing the values of d1 and d2. Technical result: resolving the ambiguity in distance measurement of the thickness of the oil. 1 Il.

The invention relates to remote passive ways of measuring the film thickness of the oil, including crude oil itself, and can be used to resolve ambiguities in the measurement of film thickness in the millimeter wavelength range.

It is known that when determined by radiometric measuring the thickness of a film of oil spilled on the water surface, may be the ambiguity of the obtained measurement result, due to the periodic dependence of the total radiation received film of oil on its thickness [1]. There is described a method of removing a specified ambiguity, which consists of making measurements at several frequencies with subsequent processing of the measurement results according to a given program.

However, the application of the known method is not always possible to solve the ambiguity problem, since the measuring receivers have different sensitivity at different frequencies. In addition, atmospheric attenuation unstable in the frequency range, and the presence in the atmosphere of water vapor is the Oia. Such a device has a large weight and size characteristics compared to single-channel (single frequency) meter.

The task of the invention is to solve the problem of disambiguation for remote measurement of the film thickness of the oil, including the oil spilled on the water surface.

This technical result is achieved that the way to resolve the ambiguity in the measurement by passive radiometric measuring the thickness of a film of oil spilled on the water surface, based on the reception of radiation of the reflected noise unpolarized sky radiation from the film of oil on one frequency measure vertically polarized components of the electric field in noise unpolarized radiation of the sky at two angles of measure1 and2, which set the direction to the Zenith, and the angle values are set with the condition1<2, each of the angles is not equal to the Brewster angle for the measured oil, then sent serially measuring angles1 and2, ustanavlivaetsya waves mirror and respectively penetrates vertical polarization components, taking into account the phase difference, due to the difference in behavior of these components to the input of the meter is proportional to twice the thickness of the film of oil, for each angle calculate the film thickness d1 and d2, respectively, and the actual film thickness of the oil is determined according to a predetermined algorithm on the basis of comparison of the obtained values d1 and d2.

The inventive method is illustrated in the drawing, which shows:- the measured value of the vertical component of the electric field noise radiation from the sky at angles of measurement1 and2, respectively, are installed on the direction to the Zenith;- components refracted at the boundary between media air film of oil;- components refracted at the boundary between media film of the oil - water;- mirrored components;components, paratragedy from border media film of the oil - water;components, paratragedy from border media film of the oil - air;- measured values of total f">2, respectively, are installed from the normal to the surface film of oil; d is the film thickness of the product; And - radiometric probe.

The method is as follows.

First, measure vertically polarized component of the electric field in noise polarised radiation from the sky, setting the meter first angle1from the direction to the Zenith, then angle2. Thus corners1and2choose not equal to the Brewster angle for the material being measured. According vertically polarized components of the electric field E01and E02respectively calculated by the Fresnel equations mirrored from the flat boundary of a homogeneous isotropic medium air film of oil and penetrazione from the bottom edge of the oil film at the boundary between media film of the oil - water surface at a known refractive indices of media: air - n1water - ninand the real part of the dielectric constant of the oil -nincluding crude oil itself, considering the angles perenia1and2[2].

Then the probe is directed to a film of petroleum products angles1and2installed from the normal to the film surface of the oil in the direction of the film, and is measured at each angle1and2the amount of coherent waves mirror and respectively paratragedy vertical polarization components, taking into account the phase difference caused by the difference in behavior of these components to the input of the meter is proportional to twice the film thickness of the oil [3]. The amount of coherent waves can be represented as:
E2ISM= E2Zer+E2lane+2EZerElanecos,
where EISM- measured amounts of coherent waves at the respective corners of measurement1and2;
EZerand Elaneis calculated by the Fresnel mirror and penetrazione vertical components the WMD radiation of the sky.

On the measured values of Edim1and EISMcalculate for each angle measurement1and2/
cos= [E2ISM-(E2Zer+E2lane)]/2EZerElane
how to determine the phase shift in degrees for each angle measurement:
= arccos[E2ISM-(E2Zer+E2lane)]/2EZerElane
then the phase shift in radians
= ()/180
On the other hand (see drawing) the phase shift in radians for the structures of environments can be defined for each angle measurement1and2and the corresponding angles of refraction1and= 2f0tenvironments-2f0twho,
where tenvironments- time shift in the medium of oil, defined by the expression

twho- time shift in the air for the time penetrating signal from the oil in the air environment, defined by the expression
twho=AR/s=(2dsinsin)/scos
where C= 3108m/s - velocity of propagation of radio waves in free space.

The phase shift in radians between the mirror and pretraining components for each angle measurement1and2and corresponding angles of refraction1and2on the border environments is expressed by the formula:

where0- average cleared.

When=limit the unambiguous value of the measured film thickness of the oil at every angle measurement1and2according to the formula:

If the phase shift>receive an ambiguity in determining the film thickness. The criterion for the transition to the ambiguity of the thickness determination is the differences of the measured values of the film thickness at the corners1and2, that is, d1d2.

In this case, if d2>d1then the value of the phase shift lies within 360o. For this case, specify for each angle, the phase shiftaccording to the formula

and the actual value of the film thickness is determined as follows:

If d1>d2then the value of the phase shift exceeds 360oand dealing with ambiguity is conducted according to the following formulas:
)]/180,

The achievement of the task, i.e., eliminate ambiguity, judged by coincidence with a given beforehand accuracy, for example 3%, the obtained values of the film thickness d'FAQand d'FAQand dFAQand dFAQrespectively.

If for the case when d1>d2when calculating according to the relevant formula does not match the received values of dFAQand dFAQit defines the limit of the range of the measured thickness in the frequency range of the radiometric measuring device.

LITERATURE
1. R. Goodman, H. Brown, J. Bitner. The measurement of the thickness of oil on water. Proceedings of the fourth international conference Remote sensing for marine and coastal environments", v.1, 17-19 march 1997, Orlando, Florida, USA, pp.1-31-1-40 (prototype).

2. Kaliteevsky N. And. Wave optics. High school, M., 1978.

3. Landsberg, C. Optics. Publishing House "Science". The main edition of physico-mathematical literature. M., 1975.


Claims

The way to resolve the ambiguity in the measurement of film thickness Nefteprodukt radiation reflected noise unpolarized sky radiation from the film of oil, characterized in that on one frequency measure vertically polarized components of the electric field in noise unpolarized radiation of the sky at two angles of measure1 and2, which set the direction to the Zenith, and the angle values are set with the condition1<2, each of the angles is not equal to the Brewster angle for the measured oil, then sent serially measuring angles1 and2, are installed from the normal to the film surface in the direction of the film, and is measured alternately at every angle sum of coherent waves mirror and respectively penetrates vertical polarization components, taking into account the phase difference caused by the difference in behavior of these components to the input of the meter is proportional to twice the thickness of the film of oil, for each angle calculate the film thickness d1 and d2, respectively, and the actual film thickness of the oil is determined according to a predetermined algorithm on the basis of comparison of the obtained values d1 and d2.

 

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