JPH07311106A - Water pressure detection device - Google Patents

Abstract

PURPOSE:To provide a water pressure detection device in which malfunction is not caused by waves. CONSTITUTION:The device is provided with a water pressure sensor 1 which detects water pressure fluctuation signal under water, a characteristic detection means 2 which detects parameters such as cycle, wave height value, etc., of the fluctuation signal detected by the water pressure sensor 1 at a specified timing period, a reference value calculation means 3 which calculates reference value based an the detected parameter, and, a means 4 which compares the reference value with the characteristic value of the water pressure fluctuation signal and discriminates the presence of a moving object.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water pressure detecting device for detecting the presence or absence of a moving object such as a ship underway in water.

[0002]

2. Description of the Related Art Conventionally, there are some which use a water pressure sensor for detecting a variation in water pressure in order to detect a ship or the like underway from underwater. In this water pressure detection device, a water pressure sensor constantly detects a fluctuation in water pressure, while the water pressure signal of the ship is an SCF (single, cycle, frequency) signal, and the duration (cycle) and signal level of the detection signal are the same as those of the ship. It was judged that the ship had arrived when the water pressure signal was at about the same level.

[0003]

In the above-mentioned conventional water pressure detecting device, the cycle and level reference values for discriminating whether or not the water pressure signal is a ship are fixed. If it changes, it will be difficult to discriminate between the wave water pressure signal and the ship water pressure signal, and it is judged that the ship has arrived due to the occurrence of a wave of a water pressure signal similar to the ship water pressure signal, even though the ship has not arrived, There was a problem of malfunction.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a water pressure detecting device in which malfunction does not occur due to waves.

[0005]

The water pressure detecting device of the present invention includes a water pressure sensor 1 for detecting a water pressure fluctuation signal in water, as shown in FIG. 1, and the water pressure sensor for detecting a predetermined timing period. The characteristic detecting means 2 for detecting the characteristic identification parameter of the fluctuation signal, the reference value calculating means 3 for calculating the reference value based on the detected parameter, and the reference value and the characteristic value of the water pressure fluctuation signal are compared. And means 4 for determining the presence or absence of a moving object.

[0006] In this water pressure detecting device, for the water pressure fluctuation detected by the water pressure sensor, a parameter such as a cycle or a peak value is detected for each predetermined timing period, and a reference value is calculated based on this detection parameter. It Therefore, this reference value is a value that changes depending on the wave condition. The reference value that changes depending on the wave condition is compared with the detection characteristic of the water pressure fluctuation signal, for example, the period or the crest value, and the presence or absence of a moving object is determined according to the comparison result.

[0007]

The present invention will be described in more detail with reference to the following examples. FIG. 2 is a block diagram of a water pressure detecting device according to an embodiment of the present invention. This water pressure detection device is installed in water and has a water pressure sensor 11 for detecting only a variation in water pressure,
A signal receiving circuit 12 that receives the transmission of the fluctuation signal from the water pressure sensor 11 and the fluctuation signal are taken in to discriminate whether the fluctuation signal is a wave signal or a ship water pressure signal,
The discrimination circuit 13 which outputs the determination result is provided.
As the discrimination circuit 13, for example, a CPU having an A / D conversion function is used.

Generally, when the ship water pressure signal is superimposed, the ship water pressure signal has a longer cycle and a higher level than the case of only waves. Further, since the ship water pressure signal is negative, it can be distinguished from the wave water pressure signal. Therefore, in this embodiment, first, the processing for identifying the wave characteristics is always performed at a constant cycle, the average of the cycle and the peak value of the fixed wave characteristics is obtained, and the average of these cycles and the peak values is obtained. The value is calculated. This processing is executed by the discrimination circuit 3. As shown in FIG. 3, this wave characteristic identification process is performed by
Hourly, for 6 minutes.

In the apparatus of this embodiment, in addition to the wave characteristic identification, the water pressure sensor 1 detected by performing data sampling at a cycle of 500 ms for 100 ms.
Is compared with the reference value to determine whether or not it is a water pressure signal for a ship (see FIG. 3). The reference value is calculated based on the average value of the period and the peak value obtained by the wave characteristic identification processing. This processing is also executed by the discrimination circuit 13.

Next, the details of the wave characteristic identification processing will be described with reference to the flow chart shown in FIG. In the embodiment apparatus,
When the timing of the wave characteristic identification processing is entered, first, the output of the water pressure sensor 1 is sampled and captured (step ST
1) The value at the time of sampling and the value at the time of the previous sampling are compared to determine whether positive / negative inversion, that is, a cross point at which a new fluctuation signal is generated (step ST
2) If the positive or negative level is the same, the counter is counted up (step ST3), but in the case of positive / negative inversion, that is, at the 0 cross point, the count value up to that point is stored and the counter is reset (step ST3). S
T4).

Next, in step ST5, it is determined whether or not the polarity has been reversed, that is, whether or not the vibration waveform having an increasing tendency has decreased, and conversely, the oscillation waveform having the decreasing tendency has an increasing tendency. If it changes from increase to decrease or decrease to increase, the value at the time of the change is stored as a peak value (step ST6). Next, it is determined whether or not sampling by the set number is completed, that is, whether or not the sampling number in the identification processing period 6 minutes in FIG. 2 is completed (step ST7). However, if the set number of samplings have been completed in step ST7, the count value from each 0 cross to 0 cross, that is, the half cycle count value is averaged and The average of the peak values is calculated (step ST8). Assume that the average count value and the average peak value are the identification values of the wave characteristics, and finally, the determination level for discrimination = m × peak average value, determination time = n × count average value are calculated (step ST9), the judgment level and the judgment time are calculated. Then, the operation ends. The determination level and the determination time obtained as described above are used as the determination level and the determination time for the next data sampling discrimination process.

Next, with reference to the flow chart shown in FIG. 5, a process of determining whether or not the water pressure signal is a ship will be described.
This processing is executed every arrival of the sampling period of 500 ms shown in the figure. First, when this process starts, it is determined whether the output of the water pressure sensor 1 is negative pressure (step 11). In the case of the ship water pressure signal, since the pressure is negative, the determination is YES in this case, the counter is counted up (step ST13), and it is determined whether or not the level of the obtained signal is equal to or higher than the water pressure determination level ( In step ST14), if the result of the determination is equal to or more than the determination, the look is turned on. The look-on indicates that the water pressure determination level is equal to or higher than the reference value. If the water pressure determination level is equal to or lower than the water pressure determination level, step ST15 is skipped. Next step ST
At 16, it is determined whether or not there is a look, and if there is no look (OFF) up to that point, the operation is terminated as it is, in preparation for the arrival of the next sampling cycle. If the look is present (ON), it means that the water pressure determination level is equal to or higher than the reference value. Therefore, it is further determined whether or not the count value is equal to or longer than the determination time. Indicates that the cycle is larger than the reference value (step S
T17), in this case, since the level and the cycle are both larger than the reference value, the discrimination circuit 3 outputs that the ship water pressure signal has arrived. In step ST17, when the value of the detected counter is equal to or less than the determination time, it is determined that a normal wave signal has arrived, and the operation is terminated to prepare for the next sampling time. Further, in step ST11, when it is not negative pressure, it can be estimated that this is not the ship water pressure signal. Therefore, the counter is reset here and the look is also reset (step ST12), and similarly, the sampling time of the next timing cycle comes. Prepare for

[0013]

According to the present invention, characteristic parameters such as a cycle and a peak value are detected for a fluctuation signal output from a water pressure sensor at a predetermined cycle at all times, and a reference value is calculated based on this parameter. , The calculated reference value is compared with the output signal of the water pressure sensor, and when it is larger than the reference value, it is determined that there is a moving object, so the reference value is changed according to the wave condition. It is possible to obtain a water pressure detection device that has a high detection probability and little malfunction even if the wave condition changes.

Further, since the intermittent operation can be performed, there is an effect that it can contribute to reduction of power consumption.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of the present invention.

FIG. 2 is a block diagram showing a configuration of a water pressure detecting device according to an embodiment of the present invention.

FIG. 3 is a time chart for explaining a wave characteristic identification process and a data sampling discrimination process of the water pressure detection device according to the embodiment.

FIG. 4 is a flowchart for explaining a wave characteristic identification process in the water pressure detection device according to the embodiment.

FIG. 5 is a flowchart for explaining the data sampling discrimination processing in the apparatus of the embodiment.

[Explanation of symbols]

 1 Water Pressure Sensor 2 Characteristic Detection Means 3 Reference Value Calculation Means 4 Moving Object Discrimination Means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takehisa Nagayama 1 Nishinokyo Kuwahara-cho, Nakagyo-ku, Kyoto Shimadzu Corporation Sanjo Factory (72) Inventor Takatoshi Hotta 1 Nishinokyo Kuwabara-cho, Nakakyo-ku, Kyoto Shimadzu Corporation Sanjo factory

Claims (1)

[Claims] 1. A water pressure sensor for detecting a water pressure fluctuation signal in water, a characteristic detecting means for detecting a characteristic identification parameter of a fluctuation signal detected by the water pressure sensor in a predetermined timing period, and a characteristic detecting means based on the detected parameter. A water pressure detecting device, comprising: a reference value calculating means for calculating a reference value according to the present invention; and a means for comparing the reference value with a characteristic value of the water pressure fluctuation signal to determine the presence or absence of a moving object.