JPH01158309A - Remote measuring apparatus of thickness of ice - Google Patents

Abstract

PURPOSE:To measure the thickness of an ice layer without contact, by providing a means, which measures the phase shifting difference between the reflected wave of a microwave from the surface of the ice, and the reflected wave from the surface of the freezing ice or the surface of the melting ice, and providing a laser light projecting means, which melts the ice layer, at the same time. CONSTITUTION:This apparatus is constituted with a laser light projecting apparatus 1 and a microwave system 2 and provided at a high place, e.g., at the side of a road. A transmitting part 21 of the microwave system 2 transmits a microwave to a specified part 4a of an ice layer 5. The microwave, which is reflected from the interface is received with a receiving part 22. The phase shifting difference (phase difference) between the transmitted and received waves is detected with a phase-shift amount detector 23. The phase shift amount is outputted as a value, which is proportional to distances l1 and l2 to the reflecting surface of the microwave. For example, the phase shift amounts between the case (Figure A), where the reflecting surface is an icing surface 5a of the specified part 4a, and the case (Figure B), where the reflecting surface is the interface after the ice layer 5 at the specified part 4a is melted with the laser projecting device 1, are obtained. The changing quantity DELTAl of distance based on the difference between both phase amounts is computed with an operator 24. The value is the thickness of the ice.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an ice thickness remote measuring device, and in particular, to a device for measuring ice thickness on ice-covered surfaces such as roads by using microwaves or moat sensing. The present invention relates to a telemetry device suitable for measuring ice thickness.

[Prior Art] For example, there is a demand for automatically measuring the thickness of ice frozen on a road in a non-contact manner and providing this as road traffic information.

The use of microwaves and moat sensing are envisioned as technologies for non-contact measurement of ice thickness, but the question is whether to use one of the amplitude and one-phase waves, which are elements of wave motion, as information on ice thickness. Become.

[Problems to be solved] ■The dielectric constant of the water to be measured is approximately 3.0 to 3.2.
The asphalt that forms the road has a value of about 4.0, which is close to 1.Therefore, there is no significant difference in the reflectance of the irradiated microwaves depending on whether there is an ice layer on the road or not. It is difficult to determine the ice state based on amplitude information.

■Also, the penetration depth of microwaves into ice (distance until the transmitted microwave power is attenuated to l/e)
In the case of a plane wave with a frequency of 10 GHz, the distance is as large as approximately 3 m, and there is little absorption of microwaves.

Microwaves penetrating through the ice surface are not absorbed sufficiently by the water layer, and after being reflected from the road surface, they return from the ice surface again, and the waves reflected from the ice surface and the waves reflected from the road surface are mixed. , its identification becomes difficult.

[Object of the Invention] The present invention solves the above problems, and its purpose is to provide an ice thickness telemetry device that can measure the thickness of an ice layer in a non-contact manner without using amplitude information. It's about doing.

[Means for Solving Problems] In order to achieve the above object, the ice thickness remote measuring device according to the present invention has the following primary structural requirements.

■There must be a laser irradiation means that irradiates a laser beam to a specific part of the frozen ice layer on the frozen surface to thaw that part.

(2) There is a microwave transmitter/receiver that directs microwaves toward the specific area and receives the reflected waves.

(2) There is a phase shift detection means for detecting the phase shift of the transmitted and received microwaves.

- There is a calculation means that receives the phase shift amount signal and calculates a distance change amount corresponding to the difference from the phase shift amount in the frozen state and the phase shift amount in the thawed state of the specific part.

Here, the term "de-ice state" includes not only a complete de-ice state in which the frozen surface of a specific part is exposed, but also the previous de-icing process and the re-freezing process.

[Function] According to the above configuration, the microwave transmitter/receiver transmits and radiates microwaves toward a specific part of the ice layer and receives the microwaves reflected at the interface, but at the same time, the phase shift detection means detects the transmitted microwave. The amount of phase shift (phase difference) between the wave and the received microwave is detected. The amount of phase shift is output as a value proportional to the distance to the microwave reflecting surface. By this means, the amount of phase shift in the case of the boundary surface after the ice layer at the specific portion has been thawed can be obtained. The distance change amount is calculated by the calculation means based on the difference between the two phase shift amounts. This distance change gives the ice thickness. Furthermore, if the amount of phase shift is detected during laser irradiation, changes in the melting thickness during the ice melting process can be obtained over time.

[Example] Next, embodiments of the present invention will be described based on the accompanying drawings.

FIG. 1 is a block diagram showing an embodiment of an ice thickness remote measuring device according to the present invention.

The embodiment device is roughly composed of a laser beam irradiation device 1 and a microwave system 2, and is installed, for example, at a high place beside a road.

The laser light irradiation bag 211 irradiates laser light toward a specific portion 4a on the road 4 in a predetermined sequence by the control unit 3, and at least removes the frozen portion 5a of the specific portion 4a of the water layer 5 frozen on the road 4. A CO2 laser is used as the laser beam irradiation bag W1t in this embodiment, which is used to melt ice, and transmits high energy efficiently. Due to the coherent nature of the laser beam, the frozen area 5, which is the target area, is
atl - can quickly and reliably thaw ice.

The microwave system 2 includes a microwave transmitter 21. Microwave receiving section 22. Phase shift amount detection section 23. and an arithmetic unit 24.

The microwave transmitter 21 directs the oscillated microwave to a specific part 4a via a transmitting antenna 21a, and the microwave receiver 22 receives the microwave reflected from the specific part 4a via a receiving antenna 22a. In this embodiment, antennas with high directivity characteristics are used as the transmitting antenna 21a and the receiving antenna 22a, and the angle of incidence and the angle of reflection are made to match, but antennas for both transmitting and receiving purposes may be used. The phase shift detecting section 23 receives the transmitted microwave from the transmitting section 21 and the received microwave from the receiving section 22, and detects the shift. It is used to comparatively detect the phase amount. The calculation unit 24 is composed of, for example, a microcomputer, and measures the distance to the reflected wave interface at the specific portion 4a based on the phase shift amount signal. A calculation is performed to calculate the distance #intersection 1 corresponding to the phase shift amount in the frozen state and the distance intersection 2 corresponding to the phase shift amount in the thawed state, and to obtain the amount of change Δ statement.

FIG. 2 is a block diagram showing a specific configuration of the microwave system 2 of the above embodiment.

The microwave transmitter 21 has a microwave frequency of 8.4GH.
a transmitting oscillator 21b such as a magnetron that oscillates z;
It is composed of an isolator 21c and a directional coupler 21d connected to a transmitting antenna 21a. Receiving section 2
2 is composed of a local oscillator 22b, a directional coupler 22C, a mixer 22d, an intermediate frequency amplifier 22e, a down converter 22f, an isolator 22g, a mixer 22h, and a phase locked loop 22i. The phase shift amount detection section 23 includes a delay circuit 23a and a phase comparator 23b.

The oscillating microwave from the oscillator 21b is transmitted to the isolator 21.
The power is fed to the transmitting antenna 21a through the main wave tube of the directional coupler 21d via the power source C. The microwaves radiated from the transmitting antenna 21a are directed toward the specific portion 4a as shown in FIG. 3(A). The incident microwave is reflected by the ice surface, and the reflected microwave is received by the receiving antenna 22a. Some of the transmission waves introduced into the sub-waveguide of the directional coupler 21d are as follows.

Local oscillator 2 synchronized by phase-locked loop 22i
The local oscillation frequency of 2b is mixed with the mixer 22h, converted to an intermediate frequency, and further converted to a down converter 22f.
will be beat down.

On the other hand, the received waves captured by the receiving antenna are sent to the mixer 2.
2d and converted to an intermediate frequency, amplified by an intermediate frequency amplifier 22e, and then beat down by a down converter 22f.

In order to correct the circuit delay difference between the intermediate frequency signals, the - intermediate frequency signal is passed through the delay circuit 23a, and then the intermediate frequency signal is supplied to the phase comparator 23b.
3b, the phase difference (phase shift fit) between both signals is compared and detected, and a phase shift amount DC signal corresponding to the phase shift amount is output.

Generally, a phase-shifted DC signal is obtained by microwave radiation, but the distance to the reflecting surface is fL (the angle of incidence is 9 and the angle of reflection is 0°), and the speed of light is the delay required to receive the C1 received wave. If time is τ, then the relational expression 2 sentences=τC...■ is obtained.

Also, if the wavelength of the microwave is input, the phase shift amount Φ is as follows: φ = Cai / input) 2π = (τC / input) 2π...
■It is given by. Based on the phase shift amount φ, the calculation unit 2
4, the distance @l to the reflecting surface is calculated.

As shown in FIG. 3(A), if the distance to the reflecting surface, that is, the ice surface during the first microwave emission is 1, the phase shift acid φ1 is φ1 = (2fL1 /in)2π
・・・It is given by l■. In the first microwave radiation, some of the waves that have penetrated into the frozen part 5a and reflected on the road surface are also received, but the measurement of the amount of phase shift is information according to the distance change part, and the road surface Since the amount of phase shift of the reflected wave from the distance is always constant, it does not interfere with distance change information.

Next, under the control of the control unit 3, the laser beam from the laser beam irradiation device 1 is directed toward the specific location 4a and irradiates the ice layer portion 5a, and the ice layer portion 5a is irradiated within a short time as shown in FIG. 3(B). Thaw the ice. This exposes the surface of the road 4. Note that the laser beam irradiation is performed after the distance sit to the ice surface is calculated.

Next, a second microwave irradiation is performed. The microwave radiated from the transmitting antenna 21a is transmitted to a specific location 4a.
reflected from the road surface, and the reflected wave is transmitted to the receiving antenna 22a.
received at As a result, as in the case of the first distance measurement, a phase shift amount φ2 proportional to the distance l1lli2 to the road surface is output.

That is, φ2 = (2J12 /λ)2π...
・Given by t.

Next, the calculation unit 24 calculates the difference Δφ=φ, 2−φl, based on the first phase shift amount φl and the second phase shift amount φ2, that is, Δφ=4π(Ai2−Tachi1) /in ...(shi) is obtained, and from this (9 equation), the distance change amount Δ sentence = 12 - m, i.e., Δ sentence = input ΔΦ / 4π ... ■ is obtained. This distance change amount Δ is This is the displacement of the reflecting surface, which corresponds to the thickness of the ice layer 5 after it has melted.

By the way, in this example, the microwave frequency is 9.
At 4 GHz, when the phase shift amount ΔΦ is 10°, it is possible to measure the ice thickness Δ 0.31. For example, if the microwave frequency is 24 GHz and the phase shift amount Δφ is 10
”, it is possible to measure 0.17 am.

In the above embodiment, the amount of phase shift is measured by the second microwave radiation after the frozen portion 5a of the ice layer 5 is completely thawed.
and the microwave system 2 can be controlled at various timings. For example, continuous measurement of the amount of phase shift may be carried out during ice melting, and in such a case, when the amount of phase shift stops changing, Completion of thawing can be detected. By considering the length of the ice melting time, it is possible to obtain a correlation between the ice thickness. Alternatively, the amount of phase shift may be measured after the ice has been thawed and refrozen.

[Effects of the Invention] As explained above, the ice thickness remote measuring device according to the present invention uses microwaves to detect waves reflected from the ice surface and waves reflected from the frozen surface or the ice surface during melting. Since it is characterized in that it has both a means for measuring the amount of phase shift between the ice layer and a laser beam irradiation means for melting the ice layer, it has a first-order effect.

■Detection of phase shift amount in frozen state and its frozen state! By actively changing the microwave reflecting surface by melting the ice and detecting the amount of phase shift, the amount of displacement is captured as the ice thickness and measured, making it easy to measure the ice thickness. Moreover, it becomes highly accurate.

-■ In particular, since a laser beam irradiation means is adopted as the ice-breaking means, instantaneous ice-breaking can be achieved without contact, and measurement can be carried out in a short period of time. Further, since the laser beam irradiation means and the microwave transmitter/receiver can be remotely controlled, an unmanned measurement and centralized monitoring system can be realized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an ice thickness telemetry device according to the present invention. FIG. 2 is a block diagram showing a specific configuration of the microwave system in the same embodiment. FIGS. 3(A), 3(B), and 3(C) are schematic diagrams showing the measurement mode according to the same example. [Explanation of main symbols] l...Laser light irradiation device, 2...Microwave system, 2
1... Transmission unit, 21 &... Transmission antenna, 22...
- Receiving unit, 22a...Receiving antenna, 23...Phase shift amount detection unit, 24...Calculating unit, 4...Road, 4a...
・Specific part, 5...Ice layer, 5a...Ice layer part. Applicant: New Japan Radio Co., Ltd. Figure 3/A-no.
(B) (C)

Claims (1)

[Claims] Laser light irradiation means that irradiates a laser beam to a specific part of an ice layer frozen on a frozen surface to de-ice that part; and a microwave that directs the microwave to the specific part and receives the reflected wave. a transmitter/receiver, a phase shift amount detection means for detecting the amount of phase shift of the transmitted/received microwave, and receiving the phase shift amount signal and detecting the difference between the phase shift amount in the frozen state and the phase shift amount in the thawing state of the specific part. An ice thickness remote measuring device comprising: calculation means for calculating a distance change amount corresponding to the distance change amount.