JPH11211846A - Snow depth meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure density of snow in simple constitution by transmitting an ultrasonic wave toward the surface of fallen snow, measuring the degree of attenuation of echo wave, and comparing it with previously housed correlation data. SOLUTION: A transducer 3 provided on the position of known distance L from the surface of fallen snow transmits an ultrasonic wave toward the surface 4 of the snow, and receives echo wave from the surface 4. An echo wave signal is A/D-converted through an amplifier 5 and a rectifier circuit 6 to be input to a level computing part 8, and the depth of snow is computed. A density computing part 9 computes the density of the snow 1 from the converted signal of the A/D converter 7. A data memory means 91 houses correlation data showing the changing degree of attenuation of echo wave by the distance L between the transducer 3 and the fallen snow surface. A density computing means 93 compares the degree of attenuation of the echo wave measured by a measuring means 92 with the correlation data stored in the data memory means 91, and density of the snow is computed from the comparison result.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for providing an ultrasonic snow depth gauge with a function of measuring snow density.

[0002]

2. Description of the Related Art In general, powdered snow has a small amount of moisture and is dry and has a low density. On the other hand, wet snow contains a lot of moisture and has a high density. When snow accumulates on the road, the amount of snow removal varies depending on the type of snow, so a certain judgment is required. That is, it is determined that the amount of snow removal is small when powdered snow is accumulated, and is large when wet snow is accumulated. For this reason, the density of snow is an important point in determining the amount of snow removal. For example, when it is determined whether a snowplow is to be dispatched when snow is piled up on the road surface, the density of the piled snow is a factor of the determination.

[0003] Conventionally, ultrasonic waves are transmitted from a transmitter / receiver toward a snow surface piled up on a snow-covered surface, echo waves reflected on the snow surface are received by a transmitter / receiver, and ultrasonic waves are transmitted. There is a so-called ultrasonic snow depth gauge that detects the depth of the snow based on the time required for the echo wave to return from the snow.
However, the conventional ultrasonic snow depth meter did not have the function of detecting the density of snow. Therefore, the snow density was measured as follows. FIG. 3 is an explanatory diagram showing how to measure the density of snow. In FIG. 3, snow S is piled on the snow surface G. The snow S is cut into a rectangular parallelepiped of length a, width b, and height h, and the weight of the cut snow is measured. Let M be the measured weight. The snow density σ is obtained from the following equation. σ = M / a × b × h

However, the above-mentioned conventional measuring method has the following problems. In fresh snow, the height h is small, so it is difficult to collect snow. The work is troublesome because the snow is manually cut and measured. It is not suitable for measuring the density of falling snow in real time.

[0005] For these reasons, there has been a demand for measuring the snow density with a simple configuration without adding a special device to the snow depth gauge.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the degree of attenuation of an echo wave when an ultrasonic wave is applied to snow is related to the density of snow. By performing density measurement using
An object of the present invention is to realize a snow depth gauge capable of measuring the density of snow simply by adding a simple configuration.

[0006]

SUMMARY OF THE INVENTION The present invention is a snow densitometer having the following configuration.

(1) An ultrasonic wave is transmitted from a transmitter / receiver toward a surface of snow piled on a snow surface, an echo wave reflected on the surface of the snow is received by the transmitter / receiver, and an ultrasonic wave is transmitted. In a snow depth meter that detects the depth of the snow based on the time required until the echo wave returns from the sensor, how the degree of attenuation of the echo wave changes depending on the distance between the transducer and the snow surface The correlation data is stored, and the correlation data is a data storage unit that prepares only a plurality of types with the snow density as a parameter, and the transducer is installed at a position at a known distance from the snow surface, Measuring means for measuring the degree of attenuation of the echo wave, and density calculating means for comparing the measurement data of the measuring means with the correlation data stored in the data storage means and calculating the snow density from the comparison result. Characterized by snowfall Total.

(2) The snow depth meter according to (1), wherein the density calculating means calculates the snow density by performing an interpolation operation on the measured data and the correlation data.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration diagram showing one embodiment of the present invention. In FIG. 1, a snow 1 to be detected is piled on a snow surface 2. The transducer 3 is installed at a position at a known distance L from the snow-covered surface 2, transmits ultrasonic waves toward the snow surface 4, and receives echo waves reflected by the surface 4. The transducer 3 outputs the received echo wave signal. This output signal is used as an echo signal. The amplifier 5 amplifies the echo signal. The rectifier circuit 6 synchronously integrates the amplified signal of the amplifier 5 and extracts a signal component from the echo signal. The A / D converter 7 converts the synchronous integration signal from analog to digital.

The level calculator 8 calculates the depth of the snow 1 based on the converted signal of the A / D converter 7. The above-described configuration constitutes an ultrasonic snow depth gauge. In the present invention, a function of detecting the density of snow is added by adding the following constituent means.

The density calculator 9 calculates the density of the snow 1 from the converted signal of the A / D converter 7. In the density calculation unit 9, the data storage unit 91 stores correlation data indicating how the degree of attenuation of the echo wave changes depending on the distance L between the transmitter / receiver 3 and the snow-covered surface. Only a plurality of types are prepared using density as a parameter. The correlation data is data obtained in advance by actual measurement. The measuring means 92
The degree of attenuation of the echo wave is measured with the transmitter / receiver 3 installed at a position at a known distance L. Density calculating means 93
Compares the measurement data of the measurement means 92 with the correlation data stored in the data storage means 91, and calculates the snow density from the comparison result. If necessary, the density calculation means 93 calculates the density of snow by performing an interpolation operation on the measurement data and the correlation data.

The operation of the apparatus shown in FIG. 1 will be described. FIG. 2 is a diagram showing an example of the correlation data stored in the data storage means 91. This correlation data is in the form of a graph.
Note that the correlation data is not limited to the graph format but may be a table format.

In the graph of FIG. 2, the horizontal axis represents the distance L,
The vertical axis indicates the decibel (dB) value of (level of the echo wave) / (level of the transmitted wave). In FIG. 2, seven types of graphs g1 to g7 are prepared using the density of snow as a parameter. Graph g1, g2, g3, g4, g5, g
6, g7 have densities of 0.5, 0.4, 0.3,
It is a graph at the time of 0.2, 0.1, 0.07, 0.05 [g / cubic centimeter]. In measuring the density, the graphs g1 to g7 are prepared in the data storage unit 91 in advance.

In the measurement, the transducer 3 is set at a position of a known distance L. The measuring means 92 measures the degree of attenuation of the echo wave. The measured data is compared with the graph shown in FIG. 2, and a graph having a value close to the measured data is selected, and the parameter of the selected graph is defined as the density of snow. The coordinates of the measured data on the graph are given from the known distance L and the degree of attenuation of the echo wave obtained by the measuring means 92.

If there is no graph having a value close to the measured data, the density of snow is calculated by interpolation. For example, the measurement data becomes X1 in FIG. 2, and the distances d1 and d2 are d1
1: Let d2 = 4: 1. At this time, the density is calculated by performing the interpolation operation of the following equation. (0.2 × 4 + 0.3 × 1) / (1 + 4) = 0.22
[G / cubic centimeter] In this way, the density of snow is measured.

The density calculation may be corrected according to the temperature of the outside air, the humidity of the outside air, and the like.

[0017]

According to the present invention, the following effects can be obtained.

According to the first aspect, only a plurality of types of correlation data indicating how the degree of attenuation of the echo wave varies depending on the distance between the transducer and the snow-covered surface are prepared using the snow density as a parameter. The density of snow is detected using the correlation data. This makes it possible to add a function of detecting the density of snow by simply adding a simple component to the conventional snow depth gauge.

According to the second aspect, since the density is detected by performing the interpolation operation, the snow density can be detected even if the number of types of the correlation data prepared in the data storage means is small. .

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention.

FIG. 2 is a diagram showing an example of correlation data used in the present invention.

FIG. 3 is an explanatory diagram showing a conventional method of measuring snow density.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Snow 2 Snow-covered surface 3 Transceiver 4 Surface 8 Level operation part 9 Density operation part 91 Data storage means 92 Measurement means 93 Density calculation means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshinori Ishii 1-5-13 Shinkawa, Chuo-ku, Tokyo Inside Yokogawa Wezak Corporation

Claims (2)

[Claims] An ultrasonic wave is transmitted from a transmitter / receiver toward a snow surface piled up on a snow surface, an echo wave reflected on the snow surface is received by the transmitter / receiver, and the ultrasonic wave is transmitted. In a snow depth meter that detects the depth of snow based on the time required for the echo wave to return, how the degree of attenuation of the echo wave changes depending on the distance between the transducer and the snow surface. The correlation data shown is stored, and the correlation data is stored in a plurality of types using the snow density as a parameter, and when the transducer is installed at a position at a known distance from the snow-covered surface, Measuring means for measuring the degree of wave attenuation, and density calculating means for comparing the measurement data of the measuring means with the correlation data stored in the data storage means, and calculating the snow density from the comparison result. Snow depth gauge. 2. The snow depth gauge according to claim 1, wherein said density calculating means calculates the snow density by performing an interpolation operation on said measurement data and correlation data.