WO2015141935A1 - Digital snowfall measuring device - Google Patents

Abstract

Provided are a snowfall measuring method and a snowfall measuring device that use a single laser distance measurer. The snowfall measuring device of the present invention comprises: a step motor including a rotating shaft; a laser distance measurer connected to the rotating shaft of the step motor at a predetermined angle with respect to a vertical plane; and a control unit controlling the step motor and rotating the laser distance measurer, and controlling the laser distance measurer and measuring the distances to multiple target points. According to the present invention, because the laser distance measurer is attached to the shaft of the step motor at a slight angle to rotate, snowfall that is scattered along a circle on a surface of snow can be measured at multiple points.

Description

Multipoint Snowfall Measuring Device

The present invention relates to an apparatus for measuring snowfall, and more particularly, to an apparatus for more practically and reliably measuring the depth (snowfall) of snow accumulated on the ground.

With the development of the Internet and communication networks, weather-related data measurements are being automated using computers, communication equipment and sensors.

Snowfall measurement is one of the areas of high interest in the field of automatic measurement due to the importance and necessity of automation, especially when the location of the target point is far from the weather center or residential area.

Because of this, many manufacturers have been developing snow measurement equipment based on a variety of techniques, including laser distance meter, ultrasonic measurement, visual signal (image signal) processing, and mechanical measurement methods.

Snowfall measurement equipment based on the currently launched or proposed laser distance measurement technology uses one or two lasers and a receiver connected thereto (for example, Republic of Korea Patent No. 348574). This raises complaints about inconsistent measurement results and vulnerabilities to various environments in the actual measurement site. For example, if a target point of a laser transmitter is obscured or obstructed by foreign matter such as fallen leaves, dust or flying snowflakes, the measurement results may not show the desired information about the snowfall at that point. Also, if you measure only one or two points in an area of 1 meter x 1 meter, the measured value cannot represent the total area.

Models based on ultrasonic signals are widely used, but these models have weaknesses in terms of measurement accuracy due to the characteristics of the ultrasonic signal itself and variations due to temperature changes.

Some models based on image processing use various signal / image processing techniques to recognize the location of the point representing the depth of the eye. One of the problems with these models arises from unclear or blurred images due to snow or ice formed at target points, such as scaled bars, and multiple light sources on a straight line. Another problem is that if it is too dark, it should be lit properly. (E.g. U.S. Patent Publication No. 2011/0219868)

Methods based on mechanical measurements present a potential big problem of mechanical malfunction due to cold weather, strong winds, and ice formation. In addition, there is a possibility that the measurement result is remarkably changed depending on the type of eye. For example, if the eye is soft, mechanical devices in contact with the eye may press the eye and affect the measurement data.

Using a container to measure the amount of snow with an equivalent amount of water (e.g., U.S. Patent No. 6,044,699), or a method using a GPS signal over a large area (e.g. U.S. Patent No. 5,761,095) There are several studies relating to these methods, but these methods relate to applications other than those to which the solution provided by the present invention is applied.

In order to solve these problems while maintaining the required accuracy and consistency, one may try a laser range finder based on a structure with multiple laser transmitters and receivers. As expected, this method will be more expensive, especially when it is necessary to measure many points to meet the requirements for real life applications.

SUMMARY OF THE INVENTION The present invention has been made in view of the above, and it is to provide a snow quantity measuring apparatus which is less affected by the surrounding environment and has high reliability of the measurement result while using a single laser range finder.

The present invention proposes an apparatus for solving the conventional problems by performing a multi-point measurement of the amount of snow using a single laser rangefinder combined with a step motor. The laser rangefinder is tilted at an angle to the step motor so that the laser signals from the laser rangefinder at different points in time (or at different angles of rotation) point to different points on the eye surface or in a circle on the ground. Is attached. This method makes it possible to measure snowfall on a number of points scattered along a circle on the snow surface. The size of the circle (ellipse) may vary depending on the distance between the laser rangefinder and the eye surface, and the angle between the direction indicated by the laser rangefinder and the direction indicated by the axis of the step motor.

According to another aspect of the present invention, the present invention uses a stopper mechanism for preventing cutting or breakage of a cable connecting the controller unit and the rotating laser range finder.

According to another aspect of the present invention, the present invention uses an infrared or visible light emitting device and a phototransistor based position control mechanism.

The invention also provides a method of calibrating the device of the invention. Boxes or jigs are used that allow the target area to be raised by a predetermined height to allow the calibration procedure to calculate the angle of arrival at each point of the circle on the ground or snow surface.

According to another aspect of the invention, the proposed method calculates the average depth of the area defined by this circle. By filtering and further processing the measurement data acquired along the path, the abnormal measurements are discarded and averaged only with meaningful measurement data to produce the final result.

According to another aspect of the present invention, transmission and reception of data and transmission of power between the control unit and the laser range finder are performed wirelessly.

According to the present invention, since the laser range finder for emitting the laser beam is attached to the axis of the step motor slightly inclined, snow quantity measurement on a plurality of points scattered along a circle on the eye surface becomes possible. It is also possible to detect erroneous measurement data over time and isolate the affected point (s) until the erroneous action is corrected. Also, because more samples can be obtained for the ellipsoid on the eye surface, the average snowfall measured may be closer to the actual snowfall value compared to other methods based on one or less samples. In addition, the present invention can easily change the position of the measuring point when finding a point showing an abnormal result. According to the invention it is possible to change the measurement sensitivity. In addition, according to the present invention, since only a low-cost device including one laser range finder and a step motor is used, it can be made in a relatively smaller housing with high cost efficiency and lower complexity.

1 is a conceptual diagram showing the configuration of the snow amount measuring apparatus of the present invention.

2 is an explanatory diagram for explaining a laser beam sending operation of the snowfall measuring apparatus of the present invention.

3 is a view for explaining the snowfall measurement principle of the snowfall measuring apparatus of the present invention.

4 is a view for explaining the operation of the snow amount measurement device of the present invention to measure the snow amount along the circle on the eye surface.

5 is an example of a measurement data graph having protrusion values and depression values.

6 is a diagram illustrating a method of performing the calibration of the present invention using a tool having a height Lref for a measurement performed at a given time t.

7 is a flowchart illustrating a calibration process according to an embodiment of the present invention.

8 is a view showing a multi-point snowfall measuring device accommodated in a protective housing.

9 shows a stopper mechanism for preventing the disconnection of the cable connecting the laser range finder and the step motor.

10 shows the stopper mechanism as seen from another time point.

11 shows an optical sensor method for the repositioning method of the present invention.

12 is a flowchart for explaining a motor repositioning process.

13 is a diagram showing how the resetting algorithm uses the circular positions when the step motor rotates once.

14 is a block diagram illustrating a configuration of an embodiment for wirelessly transmitting power and data between a controller and a laser range finder.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the following description, "depth" of the eye refers to the height of the eye from the ground surface, and "circle", "circle", "ellipse" means the projection of the laser light from the laser range finder attached to the step motor at an angle ( It is used interchangeably to represent a circular pattern formed on the eye surface by projection. In this document, when referring to a projected laser signal pointing to a specific point or on the eye surface, it also includes a reflected signal that is reflected off the eye surface and returns to the laser range finder along the exact same path, repeated description of the return signal. Is omitted.

The snowfall measurement system according to an embodiment of the present invention shown in FIG. 1 includes three modules: a laser range finder 10, a step motor 11, and a controller 12.

As shown in FIG. 1, the laser beam 16 projected by the laser range finder 10 attached to the step motor 11 is tilted at an angle to the step motor 11. Since it is attached in the form, as the laser rangefinder 10 rotates by the step motor 11, it generates a trajectory of elliptical (or circular) 14 on the eye surface 15. For snow cover measurement, the laser range finder 10 sends a laser signal to a target point on the eye surface, receives a signal reflected on the eye surface, and calculates a distance to a point on the eye surface 15 indicated by the laser beam. . The distance data is transmitted to the control unit 12 and / or the central server, where the control unit 12 processes and stores the data.

2 shows how the laser range finder 10 is tilted and attached to the motor shaft 13 to change the direction of the laser signal from the laser range finder 10 as the step motor 11 rotates. . As can be seen in FIG. 2, the laser range finder 10 is slightly inclined with respect to the direction of the motor axis 13 by an angle θ. As the step motor 11 rotates about the axis 13, the laser beam 16 from the laser range finder 10 forms a circular shape. The radius of the circle is determined by the distance and angle θ between the eye surface (or ground) and the laser range finder 10.

3 shows a single laser beam projected from the laser rangefinder 10 at a given time t and reflected back to the laser rangefinder 10 by the eye surface. As shown in FIG. 3, if the measurement distance from the laser rangefinder 10 to the surface of the eye is Ls ( t ) at any measurement time t and the distance from the laser rangefinder 10 to the ground surface is Lg ( t ) , The eye depth d ( t ) at time t can be obtained by the following equation. Where ( t ) is the angle at which the laser beam meets the ground surface at time t .

d ( t ) = (( Lg ( t ) -Ls ( t )) x sin θ ( t )

For the measurement of the next point on the circle 14 on the eye surface shown in FIG. 4, the controller 12 rotates the step motor by an angle Φ. And, in order to complete the measurement for all points on the circle, the measuring system of the present invention is t = 0 to t = n-1 until the total angle rotated by the step motor 11 is the desired angle close to 360 degrees. Repeat the same steps until, or complete the intended number of measurements for one round of measurements. Φ which represents the rotational amount between adjacent points by an angle becomes φ = 330 / n or φ × n = 330 if the total rotation of one round is 330 degrees, for example. FIG. 4 shows how measurements are made for tf in all points from t = 0 to t = n−1, rotation angle.

The depth of snow d ( t ) at each time t (rotation angle tφ) can be obtained as follows.

d ( t ) = (( Lg ( t ) -Ls ( t )) x sin θ ( t ),

( t = 0 to n-1, n = number of samples measured along a circle on the target surface area above the eye)

Lg ( t ) is measured at each time point from time t = 0 to t = n-1 (rotation angle tφ = 0 degrees to (n-1) φ degrees), and the value of θ ( t ) is measured by the calibration process. procedure), which will be described later.

When the measurement of one rotation is completed, the control unit 12 may store all the measurement data in a local storage or transmit it to an external server for further analysis.

The control unit 12 and / or the external server analyze the data by averaging the measured raw data. At this time, it is desirable to remove an abnormally high or low value from the measurement data compared with the statistical value or the reference value. Examples of reference values are the mean of data measured at neighboring points or the effective mean of snowfall previously measured at the same point. An exemplary graph measured for 24 points along a circle is shown in FIG. 5. In this example, spikes 18 and 19 and dip 20 can be removed when calculating the final result. Meaningful data can be obtained by removing significant abnormalities and then averaging the remaining values.

Before the measurement system of the present invention is first installed in the field and the measurement is performed, the following procedure should be performed. 6 is a diagram illustrating a calibration method of the present invention for a specific time t . For calibration a box or raised plane jig 21 can be used to provide a predetermined eye depth (height) as shown in FIG. 6.

7 is a flow chart showing a typical calibration procedure. Let Lg ( t ) be the distance from the laser range finder 10 to the ground surface at time t and Lr ( t ) be the distance to the jig surface. The first step in the calibration process is to measure the distance from the laser range finder 10 to the ground surface.

After initializing t = 0, i.e. after setting the step motor 11 to the initial position (step S70), the surface is cleared (S71), Lg ( t ) is measured and the step motor 11 is rotated by φ t Is increased by one (step S72). It is repeated until the step S72 to t = n (Step S73) and t = 0 measured Lg (t) at t = n-1, and to record.

Next, the jig 21 of height Lref is placed on the ground surface (the target plane is raised by Lref) (step S74) and the same procedure is repeated (steps S75, 76). In other words, measure and record the Lr (t) at t = 0 to t = n-1 φ while rotated by a step motor (11).

Lref / (Lg (t) corresponding to Lg (t) and Lr for after measuring the (t) from t = 0 to t = n-1 sin θ (t) at each time t - Lr (t) ) Is obtained and recorded (step S77). The coefficients thus calculated (sin θ ( t ) from t = 0 to t = n-1) are used to calculate snowfall d ( t ) using the measured Ls ( t ). The larger the Lref (the closer the plane 21 is to the laser range finder), the smaller the error, so the coefficient value is also closer to the actual value.

The above two steps may be performed in succession, but may be performed separately at different times as necessary.

8 shows a measuring device according to an embodiment of the invention surrounded by a protective housing 22. In front of the laser range finder of the protective housing 22 may be provided with a hood for preventing diffuse reflection of light into the laser range finder 10. In addition, the protective housing 22 may be fixed to the pillar or structure in order not to shake or move by strong winds or other external force. The controller 12 may be connected to an external communication module for communicating with a server of a remote location where additional data processing is performed.

Since the laser range finder 10 has a circuit portion, a power supply device is required for operation. Therefore, the connecting means 28 in any form is required between the controller 12 and the laser range finder 10 as shown in FIG. 9. Rotating connectors may be used to maintain the connection while the step motor 11 rotates the laser range finder 10. Rotating connectors take up considerable space and increase the overall cost of the system. It may also not be a reliable way to provide long-term signal and power in extreme weather conditions.

In the present invention, as shown in Figure 9, a high-stretch cable is used as the connecting means 28 for connecting the control unit 12 and the laser range finder 10. If the cable is used to connect the laser range finder 10 and the control unit 12, if the step motor 11 rotates in only one direction, the cable is twisted and damaged, which will eventually stop the operation. In a preferred embodiment, the step motor 11 rotates in only one direction and reverses direction before reaching the end of a 360 degree circle. For example, if you measure at 30-degree intervals, measure up to 330 degrees and reverse the direction. Thus, even if measured to 330 degrees corresponds to the measurement of 360 degrees. If you measure at 50-degree intervals, measure up to 350 degrees and reverse the direction.

If this works, you will be able to operate without causing damage to the cables or malfunctioning of the system. However, there are abnormal situations such as restarting the system. Depending on the time the system is reset, the current position of the step motor 11 may not be the position that this approach assumes when starting a round of measurements. Therefore, there is always a possibility of malfunction that can cause cable damage.

In order to prevent this type of problem, the present invention uses mechanical stoppers 25 and 26 to stop the step motor 11 from suddenly rotating beyond the limit. 9 and 10, when the step motor 11 rotates the laser range finder 10 by a predetermined angle or more, the mechanical structure 25 is blocked by another structure 26 attached to the motor bracket. You lose. 9 and 10 show the mechanical structure of the stoppers attached to the laser range finder 10, the bracket 24, the step motor 11, and the controller 12 from different viewpoints.

This stopper mechanism can be used to reposition the step motor 11. However, due to the inconstant repulsion that occurs when the stepper motor 11 hits the stopper, it is not always possible to predict the exact position of the stepper motor 11 when the two stoppers hit. Also, sometimes the step motor 11 can lose its current position data for various reasons. In particular, when the system is restarted, the probability of resetting the step motor 11 to the exact same position becomes low.

In order to obtain the accuracy and sensitivity intended by the present invention, the system of the present invention measures the distance to the target points while rotating the laser rangefinder only in one direction (for example, direction A of FIG. 10).

In order to more precisely reposition the step motor 11 and the laser range finder 10, an embodiment of the present invention uses a pair of IR detectors and a light detector such as a phototransistor. Position detection of the laser range finder 10 using an infrared generator / phototransistor pair may be implemented in various ways. For example, the plastic switch or the piece of plastic or metal passing through the photo switch may be used when the photo switch is attached to the laser range finder 10 and rotates to reach a specific position. Alternatively, the phototransistor / detector may be installed on the side or bottom, and the light reflected from the label attached to the laser range finder 10 may be detected.

In one embodiment of the present invention, a positioning mechanism based on the infrared or visible light emitting element 29 and the infrared / phototransistor 31 is used. In this embodiment, the infrared or visible light signal 32 passes through the motor bracket 24 and the hole 30 on the motor housing as shown in FIG.

11 shows an implementation of an optical sensing mechanism according to one embodiment of the present invention that allows a new round of measurement to be started at exactly the same location. While the step motor 11 rotates the laser range finder 10, the infrared (or visible) light emitting element 29 emits an infrared (visible) signal, and the infrared (visible) phototransistor 31 The strength of the signal 31 received through the drive 30 is checked. The bracket 24 rotates together with the rotation of the step motor 11, and when the direction of the infrared signal emitted from the light emitting element 29 is perfectly aligned with the hole 30 formed in the bracket 24, the received signal is received. Is the maximum intensity. In this embodiment, as shown in Fig. 11, a long and elongated hole is used so that the signal arrives only when the infrared (visible light) signal is perfectly aligned with the direction of the hole. Meanwhile, although the step motor 11 is shown in FIG. 11 and the hole is formed in the step motor 11, the step motor 11 is small so as to deviate from the light path. It is also possible to configure the diameter and to form the bracket 24 in FIG. 11 so that the cross section is a c-shape to form a long narrow hole only in the bracket 24.

12 is a flow diagram illustrating a preferred embodiment of implementing a reposition method for resetting (repositioning) a stepper motor before starting a new measurement round. FIG. 13 shows how the reposition algorithm uses positions following a single rotation of the step motor 11.

Suppose direction A is a positive direction. And when the stopper hits when rotating in the opposite direction is assumed to be the zero point (33). Every measurement round starts at the starting point 34 and ends at an end point 35 close to the 360 degree circle just before hitting the stopper again. In one embodiment, the measurement round uses only about 90% of the 360 degree circles.

The relocation process begins with completing one measurement round. As shown in FIG. 12, assuming that the step motor 11 is at the end point 35 after the last measurement round, it is necessary to make sure that the stepper must hit the stopper (close to the 36 position in FIG. 13) or is sufficient for the stopper when the process starts. Step motor 11 is further advanced to approach (S120). First, the step motor 11 is rotated near the start point 33 to its original position (S121), and then the step motor 11 is rotated so as to be located at the scan start point 37 of the shadow area between 37 and 38 ( S122). Then, the step motor 11 is moved by one step (or by a certain number of microsteps) while scanning the shaded area between 37 and 38, and reading the received infrared signal to record the position of the maximum value (S123). . This process is repeated for 2N points (S124), and when a point 39 having the maximum signal strength of the received infrared signal is determined, this point is set as a hole point (S125). Then, the motor moves backward by the predetermined number of points from this point 39 to reset the step motor 11 to the desired actual starting point 34 (S126).

When the system is restarted or powered up, the step motor 11 may not be at the end point 35 that the algorithm assumes, and if this happens the algorithm described above will find the position with the strongest signal from the beginning. It may not be. In this case, move the step motor 11 further back and forward to point 37 so that the step motor 11 firmly collides with the stopper (33 points) to start scanning the maximum light intensity point 39 as described above. do.

If the maximum point 39 is not found by either method, the stopper mechanism is used to reset the step motor 11. Basically, by stepping the stepper motor 11 against the stopper, the motor position is surely at the zero point 33. Then, after stepping on the stopper, the step motor 11 is moved as fast as several microsteps to the estimated starting point 34. Due to the bouncing back of the stepper motor 11 after hitting the stopper, this mechanism can generate an offset and produce a slightly erroneous output. If the positioning mode is changed, it will need to be recalibrated for precise measurements.

On the other hand, in the present invention, the shape of the circle is not important and may be a perfect circle or an ellipse depending on where the device is installed and the angle at which the laser signal is projected.

In the above description, the embodiment in which the control unit 12 and the laser range finder 10 are connected by using a cable has been described, but it may be replaced by a wireless device. That is, instead of using a cable connecting the laser range finder and the control unit, the wireless power transmitter is provided in the controller 12 and the wireless power receiver is provided in the laser range finder 10 so that the laser range finder ( 10) may be configured to transmit power wirelessly, and to provide wireless data communication units in the control unit 12 and the laser range finder 10 to transmit and receive data wirelessly.

An example of this is shown in FIG. 14. That is, as shown in FIG. 14, the power transmission coil 41 connected to the general power transmission circuit 42 through the cable 45 and driven by the power transmission circuit 42 is disposed adjacent to the power transmission coil 41. Power is supplied wirelessly to the laser range finder 10 by electromagnetic induction with the power receiving coil 40 connected to the power receiving circuit 44.

In addition, data communication between the laser range finder 10 and the control unit 12 may be implemented to wirelessly transmit and receive data by providing short-range wireless data communication units 43 and 44 such as Zigbee or a Bluetooth module on both sides. The power transmission circuit 42 and the power reception circuit 44 may be implemented using a general wireless power transmission and reception circuit. For example, the power transmission circuit 42 may be composed of an oscillating circuit and a driving circuit, and the power receiving circuit 44 may be composed of a receiving circuit and a rectifying and constant voltage circuit.

By wirelessly configuring the controller 12 and the laser range finder 10 in this way, a complicated mechanism due to the use of a cable can be avoided, and the rotation direction of the laser range finder 10 continues to rotate in one direction without a complicated configuration. It can be configured to scan the entire circumference of the rotating circumference to maximize the number of measuring points and reduce the possibility of malfunction due to wear of the cable.

The short-range wireless data communication unit 43 and 44 may be configured to include a digital / analog port by itself so that necessary control signals may be directly transmitted to both sides, or by adding a separate processor, data communication and necessary control between the two sides in the processor may be performed. It can also be configured to perform

As mentioned above, although the present invention has been described with some examples, the present invention is not necessarily limited to these embodiments, although all components constituting the embodiments of the present invention have been described as being combined or operating in combination. In other words, within the scope of the present invention, all of the components may be selectively operated in combination with one or more. In addition, although all of the components may be implemented in one independent hardware, each or all of the components may be selectively combined to perform some or all functions combined in one or a plurality of hardware. It may be implemented as a computer program having a. Codes and code segments constituting the computer program may be easily inferred by those skilled in the art. Such a computer program may be stored in a computer readable storage medium and read and executed by a computer, thereby implementing embodiments of the present invention.

The terms "comprise", "comprise" or "have" described above mean that the corresponding component may be included unless specifically stated otherwise, and thus, other components are not excluded. It should be construed that it may further include other components.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

The present invention can be applied to a snow amount measuring device.

Claims (15)

1. A step motor including a rotating shaft,

   A laser rangefinder connected at an angle with respect to a plane perpendicular to the rotation axis of the step motor,

   Control unit for controlling the laser range finder while controlling the step motor to control the laser range finder to measure the distance from a plurality of target points

   Snow quantity measuring device having a.
2. The method of claim 1,

   The control unit measures the distance by controlling the laser range finder, rotates the step motor by a predetermined rotation angle φ and repeats the process of measuring the distance until the laser range finder substantially one rotation, A snow amount measuring apparatus, characterized in that the snow amount is calculated from the measured distance data.
3. The method of claim 2,

   When the measurement distance t from the mirror to the surface of the eye at an arbitrary measurement point t is Ls ( t ), the distance from the mirror to the ground surface is Lg ( t ), and the angle where the laser beam meets the surface is θ ( t ). , The snow quantity d ( t ) at the measurement sequence t is

   d ( t ) = (( Lg ( t ) -Ls ( t )) x sin θ ( t )

   The snow quantity measuring apparatus characterized by the above-mentioned.
4. The method of claim 3,

   The control unit calculates an average snow amount using only the remaining measured value after removing a value higher or lower than a reference ratio by a certain ratio.

   And said reference value is a final average value of snow quantity measured during at least one rotation immediately preceding.
5. The method according to any one of claims 1 to 4,

   The snow quantity measuring device is accommodated in a protective housing for device protection,

   A snow quantity measuring device, characterized in that a hood is installed in front of the laser range finder of the protective housing.
6. The method according to any one of claims 1 to 4,

   The laser range finder is connected by a power supply and a highly flexible cable,

   And the controller rotates the step motor in one direction and reverses the direction before reaching the end of a 360 degree circle.
7. The method of claim 6,

   Snowfall measuring apparatus further comprises a mechanical stopper for stopping the step motor to rotate more than the limit.
8. The method of claim 7, wherein

   With light sensor,

   A marker placed in a position that allows the light detector to detect or block light when the laser rangefinder reaches a specific position as it rotates

   Snowfall measuring apparatus further comprising.
9. The method of claim 8,

   The label is snowfall measuring apparatus, characterized in that the light generator.
10. The method of claim 9,

    Located between the light detector and the light generator further includes a bracket that rotates together in accordance with the rotation of the step motor,

    A hole is formed in the bracket, and the hole is formed in a position such that the direction of the optical signal emitted from the light generator is perfectly aligned with the hole when the step motor is in a predetermined position. Measuring device.
11. The method of claim 10,

    And the hole has an elongated shape.
12. The method of claim 8,

    The light detector is a photo switch,

    The marker is attached to the laser range finder, when the rotation reaches a specific position while passing through the photo switch to cut off the light between the light generator and the light sensor of the photo switch, characterized in that the snow.
13. The method of claim 7, wherein

    The control unit rotates the stepper motor to be located at the scan start point after the previous measurement round, and reads the received infrared signal while moving the stepper motor one step to determine the position of the maximum value, and from this point a predetermined number of points The amount of snow measurement device, characterized in that for reversing the number of steps to reset the position of the step motor.
14. The method of claim 13,

    And the control unit rotates the step motor to be positioned at the scan start point after further moving the step motor so as to hit the stopper after the last measurement round.
15. The method according to any one of claims 1 to 4,

    The control unit includes a wireless power transmitter for wirelessly transmitting power, a data wireless communication unit for wirelessly transmitting and receiving data, and the laser range finder includes a wireless power receiver for wirelessly receiving power, and wirelessly transmits data. Snowfall measuring apparatus is provided with a data wireless communication unit for transmitting and receiving.

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