JP4007888B2 - Optical rainfall measuring device and method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is an optical system in which an optical fiber sensor for detecting a fall of a fall trap is attached to the fall rain type rain gauge, and real-time rainfall observation at a plurality of points can be performed at a remote place with a single device. The present invention relates to a rainfall measuring device and method .
[0002]
[Prior art]
In general, rainfall observations are performed by installing mechanical self-recording and electrical (data logger) observers, etc., which are certified by the Japan Meteorological Agency and sold by meteorological observator manufacturers. It was the target. However, these cannot be used where there is no power supply, and a supervisor who reads and communicates data is also required. In addition, there are many problems such as a case where the device is damaged due to a lightning surge or the like and cannot be used.
[0003]
In addition, solar cells are used in places where there is no commercial power supply, and data is transmitted wirelessly. In this case, the frequency of data transmission is once every 30 minutes from the viewpoint of power capacity and system cost. Or it is restricted to about once every 10 minutes at the earliest, and real-time data collection is not possible.
[0004]
Thus, as a method for solving these problems, various optical rain gauges have already been developed and are partly put into practical use. For example, the one proposed by the present applicant uses a Wiegand element that generates a voltage by the action of a magnetic force, uses the electromotive force of the element to emit light, and counts the number of times of light emission.
[0005]
Another method is to output direct current light from the monitoring device to the optical fiber of the rain gauge. When the rainfall reaches a certain level, the rain gauge operates to shut off the light. There is something to ask for.
[0006]
[Problems to be solved by the invention]
Since conventional optical rain gauges observe the presence or absence of light transmission conditions, they can be applied only when the distance from the observation point to the monitoring point where data is collected and processed is relatively short. Alternatively, data collection using a single-core optical fiber has a problem that a plurality of points cannot be monitored by a single device unless the wavelength from each observation point is changed using a duplexer or the like.
[0007]
The present invention provides an optical rainfall measuring apparatus and method that is relatively simple in structure that eliminates these problems.
[0008]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, in the present invention, there is a predetermined play between the overturning rain gauge , the optical fiber sensor using the FBG element, and the optical fiber sensor , and the overturning of a tensioning unit applying tensile strain to the optical fiber sensor in a fall, and a reflection wavelength measuring device for measuring the reflection wavelength of the optical fiber sensor of this prior Symbol reflection wavelength measuring apparatus having the reflection wavelength changes measured by Provided is an optical rainfall measuring device that counts the number of times to measure rainfall.
[0009]
In this rainfall measuring device, it is preferable that the regular shape of the optical fiber sensor be an ellipse or a ring approximated thereto.
[0010]
In addition, the balance weight immediately below the center of the overturned rod is used as a tension applying part to enter the ring of the optical fiber sensor, and the strain of the optical fiber sensor is subjected to tensile strain using the displacement of the balance weight caused by the overturn of the overhang. Or providing a guide member for holding the force receiving portion of the optical fiber sensor in the position of engagement with the tension applying portion, or applying a tensile strain to the optical fiber sensor only at the time of overturning to one side of the overturning rod. It is also preferable to do so.
[0011]
Furthermore, the rainfall measurement using the device of the present invention always monitors the reflection wavelength of the FBG element measured by the reflection wavelength measurement device, and obtains the difference between the current measurement wavelength and the past measurement wavelength close to the current time. It is preferable to perform the method by determining that the toppling has fallen and counting the number of falls, and obtaining the measured rainfall from the number of counts per hour.
[0012]
[Action]
The apparatus of the present invention causes a tensile strain in the optical fiber sensor by utilizing the overturning action of the overturning rod. The tensile strain that can be applied to the optical fiber by this method is not so large, but since an FBG (fiber Bragg grating) element known as a high-sensitivity element is used, even if the distance from the observation point to the monitoring point increases. The fall detection of a fall trap can be performed.
[0013]
When a tensile strain is generated in the FBG element, the reflection wavelength of light changes. If the wavelength change is monitored with a wavelength meter, it is possible to simultaneously detect the presence or absence of a tip over at a plurality of observation points using a single core optical fiber, and simultaneous observation in multiple points is possible.
[0014]
In addition, if the optical fiber sensor using the FBG element is kept in contact with the tension applying portion without play, the fall of the overturning rod to one side is delayed by the rigidity of the optical fiber, and the timing of the overturning of the left and right eyelids is delayed. However, the optical fiber sensor is formed in a ring shape that approximates the shape when a tensile force is applied in advance, and between the force receiving portion and the tension applying portion of the sensor. In the case where play is added, the pulling force is applied from the tension applying portion to the force receiving portion at the time when the kite finishes toppling, so that the above-described problems do not occur.
[0015]
Moreover, the thing using the balance weight for the fall timing adjustment provided in the overturning type rain gauge as a tension | tensile_strength provision part has the advantage that the present rain gauge can be utilized without special remodeling.
[0016]
In addition, the provision of a guide for preventing the force receiving portion of the optical fiber from coming off from the tension applying portion prevents malfunction.
[0017]
In addition, the fall detection of the eyelids can also detect the fall of the left and right eyelids respectively. In this case, it is necessary to provide two sets of FBG elements having different wavelengths in order to distinguish which of the eyelashes has fallen. Multi-point observation using a single-core optical fiber is not preferable because the total number of observation points that can be connected to one monitoring device decreases due to an increase in the number of elements. On the other hand, only one set of FBG elements can be used for one rain gauge, and the number of observation points that can be monitored simultaneously using a single-core optical fiber is increased. Can be.
[0018]
In addition, when the initial value is fixed in the measurement of the wavelength change of the FBG element and the current wavelength change is obtained by comparison with the initial value, there is a possibility that the wavelength change due to the temperature change may be mistaken for the wavelength change due to the fall of the kite. Arise. This is because the tension that can be applied to the optical fiber by the overturning force of the kite is limited, and a large wavelength change cannot be obtained. According to the measurement method of the present invention described later, the misperception can be prevented and the reliability of the system is improved.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows the overall configuration of an observation system using the rainfall measuring device of the present invention.
[0020]
In the figure, 1 is an optical rain gauge installed at each observation point, 2 is a supervisory control device installed at a remote monitoring station, etc., 3 is an optical switch provided as necessary, 4 is a reflection wavelength (distortion) of the FBG element ) Is a wavelength meter 5 for measuring the optical fiber. Two optical fibers 5 are provided in the figure, and a large number of optical rain gauges 1 are connected to each optical fiber 5 in series.
[0021]
In the method of measuring the wavelength of the FBG element, the processing speed by the wavelength meter is relatively fast, and depending on the processing method, measurement can be performed at a cycle of 50 Hz. Therefore, it is possible to monitor a larger number of rain gauges with one monitoring control device 2 by switching the connection state of each optical fiber using the optical switch 3. FIG. 1 shows an example.
[0022]
The internal structure of the optical rain gauge is shown in FIG. This optical rain gage 1 includes a tumble gutter type rain gauge provided with a tumble gutter 12, a funnel 13 for alternately injecting rain water into left and right gutters and two drain tubes 14 in a cylinder 11, and a gutter tumble. It comprises an optical fiber sensor 6 for detecting the above and an auxiliary element described later. The overturning rain gauge can be a commercial product.
[0023]
3 and 4 show details of the main part of the rain gauge 1. Here, two types of guides 7 and 8 and a stopper 9 are provided as accessory elements. Moreover, the optical fiber sensor 6 is a sensor having an FBG element, and is installed in a ring close to an ellipse. The optical fiber sensor 6 is connected to the optical fiber 5 in series.
[0024]
In the falling dredge type rain gauge, a balance weight 15 is suspended just below the center of the kite, and this weight is used as a tension applying portion, as shown in FIG. 4, the force receiving portion 6a of the optical fiber sensor 6 is played around the outer periphery thereof. Wound with G. Further, the other end of the optical fiber sensor 6 in the major axis direction is wrapped around the outer periphery of the cylinder by using one drainage cylinder 14 as a support, and is fitted with a stopper 9 via a cushioning material such as rubber so as not to come off. It is fixed.
[0025]
The optical fiber sensor 6 is preferably fixed to the drain tube 14 with a bending radius of 35 mm or more so as not to generate a loss due to winding as much as possible. It is preferable to determine the bending radius so that the force receiving portion 6a also generates as little tension as possible by bending. Further, if the force receiving portion 6a is detached from the balance weight 15 or the fit position with respect to the balance weight varies, the overturn detection of the heel becomes unstable or cannot be detected. It is preferable to provide a guide 7 that stops from coming off 15 and engages with a balance weight at a fixed position, a guide 8 that supports the middle of the optical fiber ring, and the like. The guide 7 shown in the figure is preferably shortened in length so as to prevent the balance weight 15 from being out of balance, and if the guide 8 is present, the length of protrusion of the guide 7 does not have to be so long.
[0026]
Further, if the optical fiber is caught by a surrounding object, there is a risk of disconnection or the like. Therefore, it is preferable to provide a protective cover 10 for preventing this, and the pedestal plate 16 that supports the rotation center of the existing overturn valve. It is preferable to have a role for this because an extra accessory is not required.
[0027]
The guide may be as shown in FIG. The guide 7A in FIG. 6 is for storing and holding the optical fiber in the U-slot, so that the radius of curvature and the displacement of the optical fiber 6 do not easily occur when the tensile force of the force receiving portion 6a is applied.
[0028]
In the optical rain gauge 1 configured in this way, when rainwater is injected into the kite and the overturning rod 12 falls over to one side, the balance weight 15 is displaced, and the play G with the force receiving portion 6a is reduced. Then, the play G disappears before the kite finishes overturning (see FIG. 5), and tension is applied to the optical fiber sensor 6 by further overturning of the overturned kite.
[0029]
At this time, if the force receiving portion 6a is pulled as shown in FIG. 5 and the bending radius of the force receiving portion 6a becomes too small, bending and stretching of the force receiving portion 6a is repeated, which is not preferable in terms of durability. When the wavelength change necessary for detection can be generated only by pulling by the balance weight 15, it is better not to make the change in the bending radius of the force receiving portion 6a too large.
[0030]
When the overturning rod 12 returns to the neutral position or falls over to the opposite side, the tension applied to the force receiving portion 6a is lost. Therefore, by counting the number of repeated reflection wavelength changes depending on the presence or absence of tensile strain, the rainfall can be measured in a certain unit, for example, 0.5 mm unit or 1 mm unit.
[0031]
FIG. 7 is an example of measurement of the reflected wavelength. A plurality of FBG elements with different center wavelengths are inserted in a single-core optical fiber, and the deviation from the center wavelength of the reflected wave from each element is measured. Count the number of operations. And the amount of rainfall is calculated from the number of counts per hour. FIG. 7 shows how the wavelength shifts due to the operation of the toppling whilst it has been changing at a certain wavelength until the toppling operates. Since the reflection wavelength of the FBG element also changes depending on the temperature as shown in FIG. 7B, there is a possibility that the wavelength change due to the temperature change is mistaken for the wavelength change due to the operation of the tipping over the fixed initial value. . In order to eliminate the misidentification, it is determined that the fallover has fallen when a wavelength shift of a predetermined value or more relative to the previous value is observed.
[0032]
Specific examples of the determination method are listed below.
[0033]
Method 1: As indicated by (1) in FIG. 8 (a), the difference between two consecutive sampling values is taken, and when the difference exceeds a certain value, it is determined that there is a change.
[0034]
Method 2: If there is a change in (1), as shown in (2) in Fig. 8 (a), the data immediately before that time (a) is compared with the data after the change several times, It is determined that there is a change when the evaluation continues and the change continues for a predetermined number of times.
[0035]
Method 3: As shown by (3) in FIG. 8 (b), when the difference between two points at intervals shorter than the assumed change cycle is taken and the difference exceeds a certain value Judge that there is a change.
[0036]
Method 4: As shown by (4) in FIG. 8 (c), a difference is taken with respect to the average value of several times before and after two points at intervals shorter than the assumed change cycle, and there is a difference. It is judged that there is a change when it changes more than a certain value.
[0037]
Method 5: As shown by (5) in FIG. 8 (b), the difference between the two data with an interval shorter than the assumed change cycle is taken, the difference exceeds a certain value, and When the state continues for a predetermined number of times or more, it is determined that there is a change.
[0038]
Among these methods, Method 2 and Method 5 in which continuity is evaluated and a determination is made can prevent erroneous determination due to noise and help to further improve the reliability of the system.
[0039]
If the determination function according to any one of the above methods 1 to 5 is added to the monitoring control device 2 in FIG. 1, automatic rainfall can be observed.
[0040]
【The invention's effect】
As described above, the rainfall measuring device of the present invention causes a tensile strain to occur in the optical fiber sensor having the FBG element by the overturning operation of the overturning trap using the overturning rain gauge, and the change in the reflection wavelength due to the strain is caused. Since the rainfall is obtained by counting the number of times, it is possible to eliminate the drawbacks of the conventional rainfall measuring device using an optical rain gauge. In other words, the distance from the observation point to the monitoring point can be increased, and the number of corresponding observation points can be increased with a single-core optical fiber, so that a system capable of observing a wide area in real time can be constructed. This device is inexpensive and highly reliable because it makes use of the features of an optical rain gauge.
[0041]
Note that the method for checking the overturning action of the overturning rod by the method of the present invention prevents erroneous determination and improves the measurement accuracy.
[Brief description of the drawings]
FIG. 1 is a diagram showing an overall configuration of an observation system using a rainfall measuring device according to the present invention. FIG. 2 is a diagram showing an overall configuration of an optical rain gauge. FIG. 3 is a detailed view of essential parts of the optical rain gauge. Front view [Fig. 4] Plan view of the main part of the above. [Fig. 5] Plan view showing the situation when the bag falls over. [Fig. 6] (a) Plan view showing another example of the guide (b) X- Cross-sectional view of the X-ray part [Fig. 7] (a) A diagram showing an example of measurement of the reflected wavelength (b) A diagram showing a wavelength change due to a temperature change [Fig. 8] An explanatory diagram of a judgment method for preventing misjudgment Explanation】
DESCRIPTION OF SYMBOLS 1 Optical rain gauge 2 Monitoring and control apparatus 3 Optical switch 4 Wavelength meter 5 Optical fiber 6 Optical fiber sensor 6a which has an FBG element Power receiving part 7, 7A, 8 Guide 9 Stopper 10 Protective cover 11 Cylindrical 12 Falling rod 13 Funnel 14 Drain tube 15 Balance weight 16 Base plate G Play

Claims (6)

Tumble over type rain gauge ,
An optical fiber sensor using the F BG element,
A tension applying unit that has a predetermined play between the optical fiber sensor and applies tensile strain to the optical fiber sensor when the overturning tumbles;
And a reflection wavelength measuring device for measuring the reflection wavelength of the optical fiber sensor of this,
Before Symbol reflection wavelength measuring device counts the number of times of reflection wavelength change measured by the light type rainfall measuring device to perform the rainfall measurement. The optical rainfall measuring device according to claim 1 , wherein the normal shape of the optical fiber sensor is an ellipse or an approximate ring . The balance weight directly below the center of the tipping bucket was in the tension applying portion entering into the circle of the optical fiber sensor, and to provide a tensile strain on the optical fiber sensor by utilizing the displacement of the balance weight by falling boxes according Item 3. The optical rainfall measuring device according to Item 2. Light type rainfall measuring apparatus according to any one of claims 1 to 3 provided with a guide member for holding the optical fiber sensor in the engagement position with the tensioning portion.   The optical rainfall measuring device according to any one of claims 1 to 4, wherein the tensile strain is imparted to the optical fiber sensor only when the tip of the overturning tumbles to one side.   A rainfall measurement method using the rainfall measurement device according to any one of claims 1 to 5, wherein the reflection wavelength of the FBG element measured by the reflection wavelength measurement device is constantly monitored, and the current measurement wavelength and the current measurement wavelength A rain measurement method that obtains a measured rainfall from the number of counts per hour by obtaining a difference between measured wavelengths in the near past, determining that the fall over has fallen only when the difference exceeds a predetermined value, and counting the number of falls.

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