JP2003207580A - Laser type snow depth meter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable multi-point measurement by one laser module. <P>SOLUTION: In this laser type snow depth meter, a laser beam is irradiated from a laser beam irradiation means toward a depth measuring point on the snow surface, and a part of the laser beam irregularly reflected by the depth measuring point is received by a laser beam receiving means, and the phase difference between the laser beam irradiated toward the depth measuring point and the laser beam irregularly reflected by the depth measuring point and received is measured, and the snow depth value based on a distance signal from the laser irradiation means to the snow surface is outputted. The depth meter is equipped with the laser irradiation means arranged fixedly inside a laser module casing, and an optical means for inputting the laser beam from the laser irradiation means and changing the optical axis of the laser beam irradiated from a window part formed on the casing. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to improvement of a snow depth meter using laser light.

[0002]

2. Description of the Related Art A mounting example of a conventional laser snow depth gauge will be described with reference to FIG. The measurement principle of the snow depth meter using laser light is disclosed in detail in Japanese Patent Laid-Open No. 2000-131460, and therefore its outline will be described here.

Reference numerals 1a, 1b and 2c are laser modules having three laser light irradiation means installed in parallel, and an irradiation beam is applied to the ground 2 at the top of a pillar 3 which is vertically installed on the ground 2. And is inclined and fixed to form a predetermined angle θ. Reference numeral 4 is snow cover, and 5 is a house in which the data processing device 6 is installed. A cable (not shown) connects each laser module to the data processing device 6.
E is an output of the data processing device 6 and is transmitted to a remote utilization facility.

Laser light is irradiated from the laser irradiation means of each laser module toward the depth measurement points Pa, Pb, Pc on the surface of snow, and a part of the laser light diffusely reflected at the depth measurement points is partially received by the laser light receiving means in the module. Received by,
Measures the phase difference between the laser light emitted toward each depth measurement point and the laser light diffusely reflected at the depth measurement point and outputs the snow depth value based on the distance signal from the laser irradiation means to the snow surface . Assuming that the distance from the laser irradiation means to the snow accumulation surface is L and the height from the ground to the laser irradiation means is h, the snow depth d at the depth measurement point Pa represented by the laser module 1a is d = h−L × Calculated as cos θ. The snow depths at points Pb and Pc are calculated in the same way.

[0005]

In the laser snow depth meter, the diameter of the laser beam applied to the snow surface is 6 mm.
It is a degree. In fact, the 6 mm beam is scattered by the snowflake and thus spreads over a range of 5 cm to 10 cm.

However, this range is narrow,
Since it is affected by the unevenness of the snow surface, it is not representative as snow depth data at the measurement point. Therefore, as shown in FIG. 3, the snow depth data of three neighboring points Pa, Pb, and Pc by three laser modules are averaged to obtain representative data. Therefore, the cost of the laser module has been a factor of increasing the system cost.

An object of the present invention is to solve the above problems and provide a snow depth meter capable of multipoint measurement as in the conventional case by using one laser module.

[0008]

In order to achieve the above object, in the present invention, as a first means, laser light is irradiated from a laser light irradiation means toward a depth measuring point on the surface of snow and the depth is measured. Part of the laser light diffusely reflected at the point is received by the laser light receiving means, and the phase difference between the laser light irradiated toward the depth measurement point and the laser light diffusely reflected at the depth measurement point and received is measured, In a laser type snow depth meter that outputs a snow depth value based on a distance signal from the laser irradiation means to the snow surface, the laser irradiation means fixedly arranged inside the laser module housing, and the laser light from the laser irradiation means. An optical means for inputting and changing the optical axis of the laser light emitted from the window provided in the housing is adopted.

As a second means, the optical means is
A configuration including a plurality of reflection mirror means and an operation means for changing the reflection angles of these reflection mirror means in steps is adopted.

As a third means, the optical means employs a structure including a plurality of reflection mirror means and a motor means for continuously and periodically changing the reflection angles of the reflection mirror means.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, referring to FIG. 1 and FIG.
An embodiment of a laser snow depth meter according to the present invention will be described.

In FIG. 1, 1 is a laser module casing, 7 is a laser beam irradiation means fixedly arranged inside the casing, and 8 is a glass window for irradiating and receiving laser beam formed on the side of the casing. It is a department. A block 9 indicated by a dotted line is an optical unit fixedly arranged in the laser module housing 1.
The laser beam B from the laser beam irradiating means 7 is input, and the optical axes of the laser beam radiated from the window 8 provided in the casing are B1, B
Switch to 3 axes as shown in 2, B3 and change. The optical means 9 is composed of a plurality of reflection mirror means and an operation means for changing the reflection angles of these reflection mirror means stepwise.

In the optical means 9, 10 is a first mirror, which is rotatably supported around a fulcrum 10a.
A spring 11 is coupled to one end of this mirror and is restricted to an initial position shown by a solid line by a stopper 12. A drive shaft of a solenoid 13 which is an operating means is coupled to the other end of the mirror, and when the solenoid is turned on, the mirror end is pulled in the Q direction against the spring 11, and a predetermined angle is reached until a dotted line rotational position 10 '. Rotate.

Similarly, in the optical means 9, 14 is a second
It is a mirror and is rotatably supported around the fulcrum 14a. A spring 15 is coupled to one end of this mirror and is restricted to an initial position shown by a solid line by a stopper 16. The drive shaft of the solenoid 17 is coupled to the other end of the mirror, and when the solenoid is on, the mirror end is pulled in the R direction against the spring 15 and rotated by a predetermined angle to a rotation position 14 'indicated by a dotted line.

Reference numeral 18 denotes a solenoid drive circuit built in the laser module casing 1. When both the solenoids 13 and 17 are off, the first mirror 10 and the second mirror 14 are in the initial positions indicated by the solid lines, and the laser light B from the laser light irradiation means 7 reflects on the first mirror 10 and the second mirror 14. Then, the laser light of the optical axis B1 is output.

When the solenoid 13 is off and the solenoid 17 is on, the first mirror 10 rotates to the initial position and the second mirror 14 rotates to the dotted rotation position 14 '. Due to this rotation, the reflection angle of the second mirror is shifted, and the laser beam B from the laser beam irradiating means 7 outputs a laser beam of the optical axis B2 which is shifted by a predetermined angle from B1.

When the solenoid 13 is on and the solenoid 17 is off, the second mirror 14 is rotated to the initial position and the first mirror 10 is rotated to the dotted rotation position 10 '. Due to this rotation, the reflection angle of the first mirror is shifted, and the laser beam B from the laser beam irradiation means 7 outputs the laser beam of the optical axis B3 which is shifted to the opposite side of the predetermined angle B2 from B1.

As described above, the laser light can be switched to the three axes at a predetermined cycle by the rotation operation of the mirror by the on / off control of the solenoid at the predetermined cycle, and the snow depth data of three points can be acquired by one laser module. It becomes possible.

FIG. 2 is a block diagram showing another embodiment of the present invention. The same components as those in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. The feature of the optical means 9 in this embodiment is that the first mirror 10 is fixedly arranged and the second mirror 14 is
Is connected to the rotating shaft of the motor 19 and rotates at a predetermined speed. 20 is a motor drive circuit.

The reflecting surface of the second mirror 14 and the axial direction of the motor 19 are coupled to each other with a predetermined angle offset from the right angle, and the rotation causes the mirror 14 to periodically swing to the position 14 'shown by the dotted line. The optical axis B1 of the reflected laser light from is eccentric by a predetermined angle α from the virtual center axis, and at the measurement point P on the snow surface, the laser spot is irradiated so as to periodically draw a circle of a predetermined size.

Therefore, if the measurement data is taken in at an appropriate sample timing during the period of one cycle of the rotation of the second mirror 14, it is possible to collect the data of three or more points as in FIG. Is.

In the verification of the embodiment of FIGS. 1 and 2,
By selecting the deflection angle of the optical axis of the laser light to be 10 ° and the multipoint spot distance to be 50 cm, it is possible to obtain representative data of the snow depth of the area by averaging the snow depth data of three points 50 cm apart. did it.

In the embodiment described above, the first and second
The mirror can be replaced with a prism. Figure 1
The structure of the optical means is that the rotation operation of each mirror is performed in multiple stages by the motor and the cam mechanism. Although the mechanism is complicated, it is possible to switch and change three or more axes.
The motor 19 shown in FIG. 2 can be realized by a motor that rotates at a constant speed such as a step motor or a synchro motor.

[0024]

As described above, according to the present invention,
With one laser module, it is possible to acquire snow depth data at multiple points that are separated by a specified distance, and solve the problems related to the representativeness peculiar to laser snow depth gauges with a configuration that suppresses system cost increase. be able to.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a laser snow depth gauge according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a laser snow depth gauge according to another embodiment of the present invention.

FIG. 3 is a configuration diagram showing a mounting example of a conventional laser snow depth gauge.

[Explanation of symbols]

1 Laser module housing 7 Laser light irradiation means 8 windows 9 Optical means 10 First mirror 13 solenoid 14 Second mirror 17 Solenoid 18 Solenoid drive circuit

Claims (3)

[Claims] 1. A laser beam is irradiated from a laser beam irradiation unit toward a depth measurement point on the surface of snow, and a part of the laser beam diffusely reflected at the depth measurement point is received by the laser beam receiving unit, and the depth measurement point is measured. A laser formula for measuring the phase difference between the laser light radiated toward and the laser light received by being diffusely reflected at the depth measurement point, and outputting a snow depth value based on a distance signal from the laser irradiation means to the snow surface. In the snow depth meter, a laser irradiation unit fixedly arranged inside the laser module casing and a laser beam from the laser irradiation unit are input, and an optical axis of the laser beam emitted from a window provided in the casing is set. A laser type snow depth meter comprising: an optical means for changing; 2. The laser snow depth gauge according to claim 1, wherein the optical means comprises a plurality of reflecting mirror means and an operating means for changing the reflection angles of the reflecting mirror means in a stepwise manner. 3. The laser snow depth gauge according to claim 1, wherein the optical means comprises a plurality of reflection mirror means and a motor means for continuously and periodically changing the reflection angles of the reflection mirror means.