RU2743888C1 - Method for controlling the depth of optical cable laying - Google Patents

Abstract

FIELD: cable laying.

SUBSTANCE: invention can be used to control the depth of laying an optical cable including a cable without conductive elements. According to the method, a directional acoustic effect is created on the cable and, using a phase-sensitive pulsed optical reflectometer, the characteristics of the backscattering of the optical fiber are measured, while the source of the directed acoustic effect is placed on the surface above the cable and the characteristic of the backscattering of the optical fiber is measured using a phase-sensitive pulsed optical reflectometer, which is used to determine assessment of the level of the acting acoustic signal at the point of exposure e₁, then, keeping the position of the source in the horizontal plane unchanged, raise it above the surface by a known distance H, after which the characteristic of the backscattering of the optical fiber is measured using a phase-sensitive pulsed optical reflectometer, which determines the acoustic signal at the point of impact e₂. The depth of the optical cable is estimated by the distance from the cable to the surface above the cable h which is calculated in accordance with the formula.

EFFECT: control of the depth of laying the optical cable and expansion of the field of application of the method.

1 cl, 1 dwg

Description

The invention relates to measuring equipment and can be used to control the depth of laying an optical cable, including a cable without conductive elements.

Known induction methods for controlling the depth of cable laying [1-8], consisting in the fact that a generator is connected to the wire-ground circuit of the cable line and the parameters of the magnetic field excited by the current flowing through the conductor of this circuit are measured, which determine the depth of the cable ... These methods are not applicable to control the depth of laying an optical cable without conductive elements.

Known methods for determining the location of the pipeline [9, 10], consisting in the fact that a pulse generator is connected to the pipeline, acoustic signals are measured above the pipeline using acoustic sensors, the parameters of which determine the location of the pipeline. These methods are not intended to control the depth of optical cables.

The closest to the claimed one is a method for determining the location of an optical cable [11], which consists in the fact that above the cable longitudinally-transversely relative to the intended cable route, a source of directional acoustic-vibration action is moved, while a separate communication channel controls the movements of a source of directional acoustic-vibration action and the level of acousto-vibration exposure, using a phase-sensitive pulse optical reflectometer, in which the coherence length of the optical radiation source is longer than the duration of the probe pulse, measure the backscattering characteristic of the optical fiber in the absence of vibration exposure, then produce an acousto-vibration effect on the cable from the earth's surface, moving a source of directional vibration action above the proposed path, using a phase-sensitive pulsed optical reflectometer, in which the coherence length of the optical source is exercises longer than the duration of the probe pulse, measure the characteristic of the backscattering of the optical fiber under vibration and determine the location of the cable by the position of the source of directional vibration, in which the difference between the characteristics of the backscatter, measured using a phase-sensitive pulse optical reflectometer before and during vibration at the place of vibration the impact is maximum. However, this method is not intended to control the depth of the optical cable.

The essence of the proposed invention is to expand the scope.

This essence is achieved by the fact that, according to the method for controlling the depth of laying the optical cable, a directed acoustic effect is created on the cable and the characteristics of the backscattering of the optical fiber are measured using a phase-sensitive pulse optical reflectometer, while the source of the directional acoustic effect is previously placed on the surface above the cable and the backscatter characteristic is measured optical fiber using a phase-sensitive pulsed optical reflectometer, which determines the assessment of the level of the acting acoustic signal at the point of exposure e ₁ , then, keeping the position of the source of directional acoustic influence in the horizontal plane unchanged, raise it above the surface by a known distance H, and then measure the characteristic of the inverse scattering of an optical fiber using a phase-sensitive pulse optical reflectometer, which is used to determine the assessment of the level of the influencing about the acoustic signal at the point of impact e ₂ , and the depth of the optical cable is estimated by the distance from the cable to the surface above the cable h, which is calculated by the formula

(1).

(one).

The drawing shows a block diagram of a device for implementing the proposed method.

The device includes an optical cable 2 with optical fiber 3, laid below the earth's surface 1, a phase-sensitive pulse optical reflectometer 4 and a source of directional acoustic action 5.

Optical fiber 3 of an optical cable 2 laid below the earth's surface 1 is connected to the input of a phase-sensitive pulse optical reflectometer 4, and a source of directional acoustic impact is located above the cable on the surface.

The device works as follows. The phase-sensitive pulse optical reflectometer 4 measures the characteristics of the backscattering of the optical fiber 3, which determine the estimates of the signal levels induced in the optical fiber as a result of acoustic exposure at the site of exposure. A preliminary estimate of the signal level is determined when the acoustic source is placed on the surface above the cable e ₁ , and then when the acoustic source is located at the same point at a height H above the surface e ₂ . After that, the depth of the optical cable is estimated by the distance from the cable to the surface h, which is calculated by the formula (1).

In contrast to the known method, which is the prototype, the claimed method includes measuring the parameters of acoustic exposure using an optical fiber as a distributed acoustic sensor for two values of the distance from the source of acoustic exposure to the cable at one point of the cable line, which allows, in contrast to the known method, which is the prototype, to control the depth of the optical cable and thereby expand the scope of the proposed method in comparison with the prototype.

LITERATURE

1. SU 98345

2. SU 569984

3. RU 2315337

4. RU 2326343

5. RU 2635402

6. WO 2017/164765

7. RU 2699379

8.RU 2713104

9.RU 2482515

10. RU 127203

11. RU 2656295.

Claims (2)

A method for controlling the depth of laying an optical cable, which consists in creating a directional acoustic effect on the cable and using a phase-sensitive pulse optical reflectometer measure the characteristics of the backscattering of the optical fiber, characterized in that the source of the directed acoustic effect is preliminarily placed on the surface above the cable and the characteristic of the reverse scattering of an optical fiber using a phase-sensitive pulse optical reflectometer, which determines the assessment of the level of the acting acoustic signal at the point of exposure e ₁ , then, keeping the position of the source of directional acoustic influence in the horizontal plane unchanged, raise it above the surface by a known distance H, after which the characteristic is measured backscattering of an optical fiber using a phase-sensitive pulse optical reflectometer, which determines an estimate of the level of the signal at the point of impact e ₂ , and the depth of the optical cable is estimated by the distance from the cable to the surface above the cable h, which is calculated by the formula

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