JPS6311673Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an ultrasonic measuring device that can measure the amount of snowfall, etc.

Generally, a method is known for measuring the depth of snow, for example, from the propagation time of ultrasonic waves. However, the speed of sound changes depending on the temperature, and this causes errors in the measured values, so it is necessary to consider a method for correcting the errors.

The object of the present invention is to provide a measuring device that can appropriately correct such errors.

The present invention will be explained below along with one embodiment of the present invention. In FIG. 1, 1 is the ground, and 2 is the snow that has piled up on the ground 1, which is the object of measurement by this device. Reference numerals 3 and 4 are transmitting heads, which emit ultrasonic waves toward the ground 1 (when it is snowing, the surface of the snow 2). A receiving head 5 receives the ultrasonic waves emitted by the transmitting heads 3 and 4 and returned after being reflected from the ground 1 (or snow surface). Reference numeral 6 denotes an arm that holds the transmitting heads 3 and 4 and the receiving head 5 at regular intervals. In this example, the receiving head 5 is installed at the same position as the transmitting head 3, and the transmitting head 4 is installed at a position apart from the transmitting head 3. 7 is a pole and arm 6
be held at a constant height above the ground.

Figure 2 shows the electrical configuration of this device.
1 is a sine wave (e.g. 25KHz) intermittent wave (e.g.
This is a tone burst generator that generates 1 ms continuous, 1 s off), and is controlled by the control unit 16. 12,1
3 is a transmission amplification circuit that amplifies the output of the tone burst generator 11 to a predetermined level and applies it to the transmitting heads 3 and 4; 14 is a transmitting amplifier circuit that amplifies the ultrasonic electrical signal received by the receiving head 5 to a predetermined level; This is a receiving amplifier circuit. 15 is a slice circuit that outputs an output to the control unit 16 when the output of the amplifier circuit 14 exceeds a certain level, and 16 is a control unit that controls the transmission of the tone burst generator 11 and also controls the transmission and reception (slicing). The time until the output of the circuit 15 is output is measured. In this case, the transmitting head is 3,4
Since there are two at separate positions, two waves are received, so the control unit 16 measures two times from wave transmission to wave reception. The control unit 16 also calculates the snow depth from the two measured times. 17 is the control unit 1
6, the snow depth measured and calculated by the control unit 16 is output as a digital quantity.

FIG. 3 shows the operating waveforms of this device, where A indicates the electrical input to the transmitting head 3 and B indicates the electrical input to the transmitting head 4 (corresponding to the transmitting waveform). C is the electrical output (corresponding to the received waveform) of the receiving head 5, and shows how the ultrasonic waves emitted by the transmitting heads 3 and 4 arrive with a time lag.

Next, the operation of this embodiment will be explained. Ultrasonic waves emitted from the transmitting head 4 are reflected by the ground (or snow surface) and received by the receiving head 5. A time T ₁ is measured by the control unit 16 to which this received signal and the output of the tone burst generator 11 are added.
Further, the ultrasonic waves emitted from the transmitting head 3 are similarly received by the receiving head 5, and the time _T2 from the emission to the reception is also measured by the control section 16.
Here, when calculating the snow depth from T ₁ and T ₂ , the sound speed V can be expressed as follows.

V=(H ₂ −H ₁ )/(T ₂ −T ₁ ) It is assumed that H ₂ is the distance from the ground to head 3.5, and H ₁ is the distance from the ground to head 4. The following formula also holds.

2(H ₁ -h)/V=T ₂ Therefore, the snow depth h is as follows.

h=H ₁ −T ₂ (H ₂ −H ₁ )/{2(T ₂ −T ₁ )} Therefore, it is possible to accurately measure snow depth without being affected by changes in sound speed caused by temperature, etc. can.

Further, it is usually convenient to use the same transmitting/receiving head as the transmitting head 3 and the receiving head 5. In addition, although snow accumulation has been described in the embodiment, the present invention can be applied not only to snow accumulation but also to devices that measure water levels and other lengths.

As is clear from the above embodiment, the present invention has a configuration in which two transmitters of different heights and one receiver are provided, so the snow depth can be detected without being affected by temperature. This has the effect of making it simple with just four rules. Furthermore, even if a microcomputer is used in the control section, there is only one input port, so easy control is possible.

[Brief explanation of the drawing]

FIG. 1 is a side view of an ultrasonic measuring device according to an embodiment of the present invention, FIG. 2 is a block diagram of the same, and FIG. 3 is a signal waveform diagram of the main parts. 1...ground, 2...snow, 3...transmission head, 4
...Transmission head, 5...Reception head, 16...Control unit.

Claims (1)

[Claims for Utility Model Registration] A first transmitting head mounted at a first height _H1 so as to transmit toward the ground, and a first transmitting head mounted at a second height _H2 so as to transmit toward the ground. a second transmitting head, a receiving head mounted at the second height _H2 , which receives the waves reflected from the ground by the first and second transmitting heads; High h = H ₁ - _{T 2} (H ₂ - H ₁ )/2 (T ₂ - T ₁ ) (where T ₁ : Reception time by the first transmission head T ₂ : Reception time by the second transmission head) An ultrasonic measuring device comprising a calculating means for calculating.