JPS61160077A - Device for measuring altitude of cloud base - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is based on the concept shown in claim 1,
This invention relates to a device for measuring cloud base height.

[Prior art]

Devices of this type include CH-PS 623, 119 and D
E-PS 2,924,490 and is well known. These known devices are designed to indicate a high value as the cloud base height, which corresponds to the maximum stored signal value. They are therefore only satisfactory in the absence of rainfall. When it rains or snows, the transmitter sends pulses of light that are reflected not only from clouds but also from raindrops and snowflakes. Therefore,
The signal value corresponding to this will be larger than the signal value corresponding to only clouds. After all, conventional devices may not be able to accurately indicate the height of clouds when it is raining.

[Object of the present invention]

The purpose of the invention is to overcome the above-mentioned difficulties and to distinguish between clouds and rain. This object is solved by the structure described in claim 1.

According to the configuration of claim 4, the fact that it is raining is additionally displayed.

[Means to solve the purpose]

The device presented here basically complies with CH-PS 628.139 and DE-PS 2,9
It operates on the same measurement principle as the device disclosed in US Pat. No. 24,490. Therefore, if any component or function related to measurement of this device described below is the same as that of the conventional device, the description will be simplified. Furthermore, the description of the embodiments also serves as a description of means for achieving the object.

[Explanation of Examples]

The device of the invention includes a transmitter 1 consisting of a laser diode.
, which emits regular, short, high rise rate light impulses 8 controlled by a control device. Although not shown, a thermostat is placed on the laser diode to monitor the operating temperature of the laser diode to keep it constant. The control device 2 monitors the optical output of the semiconductor laser using the optical sensor 4, and monitors the pulse current for driving the semiconductor laser so that the optical output becomes constant. In this case, the light output is set to such an extent that there is no danger even if a person looks into the transmitted laser light. The light pulse 5 reflected from the cloud is received by a receiver 6 equipped with a light sensor and transmitted to an integrator 9 via an amplifier 7 and an analog switch 8. The analog switch 8 together with its control device constitutes a gating device, which passes the output signal of the amplifier 7 only during a segmented time. The optical impulses are transmitted in time segments that are shifted by a time interval. The integrator 9 integrates a predetermined number of time segments having the same time offset with respect to the transmission of the light impulses 8. The integrated signal is converted into a digital signal value by an A/D converter 11 and transmitted via an interface 12 to a microprocessor 14 having a data storage device 13. Each time a predetermined number of time intervals are integrated, microprocessor 14 stores the integrated signal value in data storage 18 and integrator 9
Return to initial state.

The microprocessor 14 also has a gate device 8.10.
with respect to the transmission of the optical impulse, so that the time lag of the segment times is slightly larger, and subsequently the next segment time is integrated by a predetermined number. In this way, the integrated signal values are stored in the microprocessor 14 in sequence according to the height HK given by the time offset of the time segments (this height with respect to the signal values is windows 20, 21, through which the light impulses 3.5 are transmitted and received, the heating disk 22
Equipped with A blower 23 is also provided, and is arranged so that the airflow horizontally traces the two windows 20, 21. Heating disk 22 is switched on when temperature sensor 28 senses sub-zero temperatures. The blower 23 is switched on when the microprocessor 14 evaluates the measurement results to determine whether there is rain, as will be explained below. The heating disk 22 and the blower 23 prevent raindrops or snowflakes from interfering with the light impulses being transmitted through the window 20.21. Therefore, blower 2
3 is not operated continuously but is switched on only when it rains, so it consumes little power and has a long service life. In order to confirm that the windows 20, 21 are dirty and obstructing transmission and reception, a light sensor 25 is arranged, which detects light impulses that also reflect from the windows 20. The signal detected by the optical sensor 25 is transmitted to the window 20
When the output signal of the optical sensor exceeds a predetermined tolerance value, the microprocessor 14
input/use, - to the display device 27 via the control device 26,
Transmits a command to display the message "Wipe the windows." ′
The command to display the message "Wipe the windows" is blocked while the microprocessor 14 detects rain.

This is because in such a case, the signal detected by the optical sensor 25 may be caused by raindrops or snowflakes adhering to the window 20. Such raindrops and snowflakes are automatically removed by the blower 28 and heating disk 22.

The transmitting/receiving optical system 28, 29 (Fig. 1) is connected to the transmitter 3.
The luminous flux 3 emitted from the cloud and the luminous flux 5 received by the receiver 6 are arranged next to each other, taking note that as the altitude of the cloud increases, their mutual superposition becomes stronger. In the measurement area at low altitude, the transmitted light impulse 3
Only the results of multiple diffuse reflections (scattering) are detected by the receiver 6.
Just go back to . However, in a measurement area with a low altitude, the value of the received signal is small. As the height of the cloud increases, the overlap between the light beams 3 and 5 also increases, so the amount of light that returns or is reflected increases. However, as the altitude increases, the attenuation decreases in proportion to the square of the distance. In order to smooth out such an imbalance, the number of time segments integrated by the integrator 9 can be changed using the microprocessor 14 depending on the height of the cloud.
It is possible to change the difference in the division time when sending out the signal so that the magnitude of the integrated signal value is constant over the entire range of measurement altitudes as long as the situation is constant.

In the device described above, the microprocessor 14 constitutes an evaluation device. The operating program of the microprocessor 14 related to this evaluation will be explained below using the simple flowchart (diagram) shown in FIG. This invention is based on the following findings. If the integrated signal values organized according to the data storage device are used according to the altitude, for example, the graph Fl(I( )of,
In the absence of rain, the graph shown in Figure 5a is obtained. Graph Fl(H) shows that the upheaval occurs due to clouds or rain, and in this case, it is not clear whether the sharp value (highest value) of the upheaval is due to the cloud or the rain.9 In the present invention, Cloud bulges are distinguished by their steep rise and fall. This means that the density of raindrops in clouds is greater than in rainfall.
There's probably a physical explanation. For this reason, the evaluation method in the present invention smoothes the graph Fl(H),
The basic method is to differentiate a smoothed graph and determine the highest and lowest values of the differentiated graph.

A pair of adjacent maximum and minimum values is a cloud if its maximum and minimum values exceed above or below certain predetermined, empirically determined limits C1, C2. means. In order to confirm that the pair of highest and lowest values is not the result of unexpected integration due to strong noise, the height of the pair of highest and lowest values in graph F1 (H) obtained by the original measurement is determined by noise. It can be tested to see if it sufficiently outperforms the case of

The operating program of the evaluation device in the microprocessor 14 begins with the output 30 of the integral signal, which is stored in the data storage 13 in accordance with the altitude H, according to the diagram in FIG. This integral signal is, for example,
The graph Fl (H) shown in FIG. 4a is provided.

In the second program step 31, the graph Fl (
H) is smoothed and the smoothed graph is shown in Figure 4b.
2 (H). This smooth graph F2
(H) is differentiated with respect to height in the next step 32,
A differential graph F3 (H) shown in FIG. 4c is obtained. The next program step 33 determines the three maximum values, namely the three highest positive amplitudes Famaxi and the three highest negative amplitudes F3mini in the differential graph F8 (H). (Determining the number of cloud layers to be four or more is practically meaningless). Subsequently, in a logic step 34, it is determined whether the three highest values F8rnax4 are greater than a certain empirically predetermined limit value C1, and the three lowest values F8m ini are smaller than the limit value C3. Determine whether or not. The above maximum value F3maxi, minimum value F3mi
If J is greater than, still less than, the limit values C1, C2, they are sent to a qualification step 84 to further determine whether they are sequentially highest/lowest/highest in terms of altitude. In this case, it is first determined whether the value belonging to the lowest altitude is the highest value or the lowest value. If it is the lowest, the value is cleared.

If it is the highest, it is determined whether the value belonging to the next altitude is the highest or lowest. If the value obtained later is the highest, the highest value obtained earlier is erased.

If the value belonging to this second altitude is the lowest, then this highest/
The height range of the lowest value pair F3 max/F8 min is stored. If the lowest value is followed by another lowest value, the subsequent one is erased. If the highest value continues, it is determined whether the highest value is followed by the lowest value. And if so, this second highest/lowest value pair F
8max/F3min is stored. As a result, in the certification step 34, it is checked whether there are -, or a plurality of consecutive maximum/minimum value pairs F3max/F3min with respect to altitude that exceed the limit values C1 and C2. Ru.

The altitude to which this pair belongs is then stored.

The certification step 34 will be explained in more detail using the example shown in FIG. In this example, the three highest values F8maxl, F3max2F3max that are larger than the limit value C1
x3 and the lowest value F8min1, F, which is smaller than the limit value C2.
9m1n2, F8min3 are used, and the limit values C1, C
2 is chosen to be very small (in practice, this limit value is chosen to be large so that only the values F3max2 and F8min1 indicated by the substantial cloud exceed the limit value). The six highest and lowest values arranged in order are determined as follows. The first value F3max1 is the highest value in this case, but since the next value F3max2 is the highest value, it is deleted. The highest value F8max2 followed by the value 1
7'3171111 comes, which is the lowest value. Therefore, the area of height to which the pair F3max2/F3min1 belongs is stored. Following the above pair comes another maximum/minimum value pair F8 max5/F3 rn in2, the height range of which is stored as well.

The lowest value F8 min2 is followed by the lowest value F3 min3, which is erased.

If, in the qualification step 34, no pair of highest and lowest values is detected, that is, no clouds are recognized. In this case, following the determination of "none" in program step 84, an integration with respect to the height is performed on the smoothed graph F2 (H), and the second qualification step 3
6, it is determined whether the integral value F5 is larger than an empirically determined limit value C3. If it is larger than the limit value, a strong reflection of the transmitted light impulse 3 will be received by the receiver 6 even though there are no clouds, which means that it is raining. On the other hand, the microprocessor 14 issues a display command 37 to the display device 27 via the E/A control device 26. The display is ``Unable to identify clouds...Rain''. It still issues a switch-on command 38 to the blower 23. Value F5 is limit value C3
If it is smaller and there is no rain, use blower 2.
3, a switch-off command 39 is issued, and a display command to display on the display device 27 the message "No clouds detected" is issued.

In the qualification step 34, one or more pairs of maximum and minimum values F3 max/F3 are determined as shown in FIG. 4c.
When min is confirmed, it can be inferred that there is a cloud at the highest value or at the altitude of each highest value. The next program - steps 41 to 49 determine whether there is rain or not, and whether there is a signal value of the graph Fl (H) that is sufficiently thicker than that due to noise at the altitude where the highest value is present. and reveals the existence of clouds. In step 41, the graph F4(H) corresponding to the smooth graph F2(H) is
is formed. However, in this case, graph F2 (H)
The operation interval, which is the altitude range indicated by the maximum and minimum values F3max/F8min, is a linear operation division.

Curve F4 (H) is the highest in curve F2 (H).
Omitting the curved part (bulge) of the curve F2(H) in the height region defined by the minimum value pair F3max/F3min,
Curve F2 (H
) is different from

To confirm that there is rain, graph F4 (H)
is integrated over the entire height region in the next program step 42 to obtain the integral value F5 at the maximum height of the measurement region.
(Hmax) is compared with an empirically determined constant value C3 in the next qualification step 43. Graph F2 (H
) is a straight-line operating section in graph F4 (H), so the integral value F5 (H) is
This is mainly due to the reflection or return of the optical impulse 3 due to rainfall. Integral value F5 (I-i) is limit value C
If the value is greater than 3, a display command 44 "Rainfall" and a switch fire command 45 to the blower 23 are issued. If it is less than the limit value, a switch-off command 46 is issued to the blower 23. For example, in FIG. 4, the integral value F5
It will be clear that (H) is very large and exceeds the limit value C3, so that "rain" is displayed. The original measured value graph Fl (
It can be seen that the magnitude of the integral value F5 (H) is due to the first bump in the graph Fl (H) or F2 (H). Since the gradual decline of these graphs does not have a lowest point in the differential graph FB (H) shown in FIG. 4C, the rise in graph F4 (H) is not like a combination of straight lines to form a curved section.

A noise graph R(H) is then formed. For this purpose, a graph Fl at each altitude, indicated by symbol 47
The absolute value of the difference between (H) and graph F2 (H) is calculated and multiplied by a constant factor value C4, such as in example 9B3. Furthermore, in step 48, the graph F4 (H)
and the noise graph R(H), a sum graph F6 (H) is formed, and in the next qualification step 49, the difference between the graphs Fl (H) and F6 (H) is determined as the pair of highest and lowest values F3max/
In the height region defined by F8min, it is determined whether the height is greater than a predetermined fixed limit value C5.

If it is not large, display command 40 "Do not recognize clouds"
is emitted. That is, in this case, the pair of maximum and minimum values F8max/F8min detected in step 33 is caused by a protrusion caused by noise, although this is inconvenient. If the difference is greater, a command 50 is issued to display the cloud low altitude. Then, the altitude H where the highest value of the highest and lowest values F8max/F8min is located
is displayed, and in that height region, the difference between the graphs Fl (H) and F6 (H) is greater than the limit value C5.

(The limit value C5 can also be set to 0 if the constant factor value is sufficiently large).

For example, in Figure 4e, the graphs Fl (H) and F6 (H
) is greater than the limit value C5 only at the raised part of the first maximum/minimum value pair F8max2/F'1m1n1 in FIG. 4C. 20. In the raised part of the highest and lowest values of F8max5/F8min2
l (H) is smaller than F6 (H), such a second pair should be due to noise rather than clouds. Therefore, in this case, the maximum cloud height F
The altitude H=4200 feet at which 3max2 exists is displayed.

Figures 5a and 5b include graphs Fl (H), F2
(H) and F3 (H) are shown, which are at altitude 39
There was a layer of clouds at 00 feet, indicating no rain. In this case, in the certification step 34, the pair of maximum and minimum values F8max1 /F8min 1 is confirmed, in the certification step 43 it is determined that the integral value F5 (Hmax) is smaller than the limit value C3, and finally in the certification step 4
9, maximum/minimum value pair F8max1 /F8min1
The value of graph Fl(H) in the height region of graph F6
(H) (greater than the limit value C5), and as a result, the cloud base altitude is displayed as the position of the highest value F8max1.

It is obvious that the operating program of the microprocessor 14 constituting the evaluation device can be configured other than that shown in FIG. In the simplest case, program steps 80 to 84 would be sufficient, in which case only one layer of highly reflective clouds would be considered (although
Compared to the operating program in Figure 3, it is possible to see more clouds with slight reflections.)
. In other words, when the largest maximum value p3max exceeds the limit value C1 and the following minimum value F3min exceeds the limit value C2, the altitude to which the largest maximum value F3max belongs is displayed as the cloud base altitude in the differential graph. do. Even in such an operating program, in order to easily check the detected cloud base height, in the next qualification step, for example, the integrated signal value F1 ( Hwolke
) exceeds a preset noise waveform. Of course, it is possible to include sub-programs corresponding to special environmental conditions such as fog, for example, in the operating program of FIG.

In order to prevent the semiconductor laser 1 located at the focal point of the transmitting optical system from being damaged by heat due to the incidence of strong sunlight,
A sunlight intensity measuring device (not shown) consisting of an optical sensor and a cover plate (shutter, not shown) that reflects sunlight may be provided. This shutter is
When the output signal of the optical sensor in the optical path between the semiconductor laser 1 and the transmitting optical system 28 exceeds a preset limit value, it is automatically activated by an electrical/mechanical device. In this case, the transmitter control device 2 is switched off.

Further, in order to protect the receiving device 6, a similar cover may be provided.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a device for measuring cloud base height, together with the path of light impulses between the device and the cloud. FIG. 2 is a block diagram of the device. Figure 3 is a flowchart of the operating program in the evaluation device (
Diagram). Figures 4a to 4e are graphs Fl, F2. FB, F4. F5. Indicates F6. Figures 5a and 5b are graphs Fl and F2 when clouds without rainfall are detected. This shows what corresponds to F8.

Claims (1)

[Claims] 1. A device for measuring cloud base height, which uses optical impulses (
3) a transmitter (1) which emits a signal, a receiver (6) which receives a light impulse (5) which is reflected from the cloud, during a segment time;
A gate device (
8, 10), regarding the transmission of the optical impulse (3), an integrator (9) that integrates a constant time consisting of a plurality of segmented times with the same time lag, and an integrator (9) that integrates a certain time period consisting of a plurality of segmented times with the same time lag, and an altitude related to the time shift of the segmented times. It is equipped with a storage device (13) that stores the signal value (F1) after integration, and a graph (F2) that smoothes the signal value related to height (H).
, differentiate the smoothed graph (F2) with respect to height, and calculate the highest value (F
An evaluation device (1
4) A device characterized by having the following. 2. The device according to claim 1, wherein the evaluation device (14) determines from the differential graph (F3) the maximum value, which is larger than and smaller than the predetermined limit values (C1, C2). Minimum value (F3max_iF3max_i
), and the highest value (F3max_i) is the altitude (H)
Select by following the lowest value (F3min_i) on the higher side of , and display the altitude to which the selected highest value (F3max_i) belongs, or display this altitude assuming it to be the cloud base altitude. The signal value (F1) after integration related to these is the limit value (C
5+F6). 3. The device according to claim 2, wherein the evaluation device (14) calculates the highest value (F3) in a graph (F3) obtained by differentiating the smoothed graph (F2).
3max_i) and the minimum value (F3min_i), the height interval between the selected maximum value (F3max_i) and the following minimum value (F3min_i) is replaced by a straight line segment and smoothed by the straight line segment. A constant or altitude-dependent noise level (R) is added to the selected graph (F4), and the selected maximum value (F4) is added to the selected graph (F4).
3max_i) is assumed to be the cloud base altitude, and the signal value integrated over the height region between the selected maximum value (F3max_i) and the following minimum value (F3min) is displayed at this height. The area is characterized by being larger than the value of the graph (F6) obtained by adding the noise level (R), or larger than a certain value (C5). 4. The device according to any one of claims 1 to 3, wherein the evaluation device (14) calculates the smoothed graph (F2) or the selected maximum value (F3max_i
) and the following minimum value (F3min_i) A smoothed graph (F4) using the altitude (H) as a straight line segment
is integrated over the altitude measurement area, and the integral value (F5) is
If is larger than the predetermined limit value (C3), then
It is characterized by emitting a signal (37, 44) indicating that there is rain. 5. A device according to claim 4, characterized in that the optical impulses (3, 5) of the device act on the optical surfaces (20, 21) in and out, and the evaluation device (14) , a blower (23) which is controlled (38, 39, 45, 46) to be switched on only when there is a signal (37, 44) indicating the presence of rain.
). 6. A device according to any one of claims 1 to 5, characterized in that the second optical sensor (25) is configured to remove dirt from the optical output surface (20) of the device. The evaluation device (14) is arranged to detect the reflected light impulses (3) and, if the output signal of the second light sensor (25) exceeds a predetermined limit value, the evaluation device (14) determines that it is dirty or , a display device (27) indicates that cleaning is required. 7. In the apparatus according to any one of claims 4 and 6, the instruction to display that the apparatus is dirty or that cleaning is required is performed when the evaluation apparatus (14) It is characterized by being ignored when the signal (37, 44) is emitted.