JP3621531B2 - Strong seismometer with automatic time calibration internal clock - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a digital strong motion seismometer installed in a remote unmanned area, and more particularly to a strong motion seismometer equipped with an automatic time calibration type internal clock.
[0002]
[Prior art]
Conventionally, seismometers mainly intended to obtain seismic response records of structure ground during strong earthquakes are called strong seismometers. This strong seismometer is activated when an earthquake of a predetermined size or larger is detected, and a servo accelerometer is used as a sensor. As shown in FIG. 4, the strong motion seismometer has a ground sensor 1 incorporating three servo type accelerometers for detecting vibrations in three directions of X, Y, and Z, and an earthquake digital signal transmitted from the ground sensor 1. It has a data processing unit 2 to receive. The data processing unit 2 includes a data recording unit, a control unit, and a data transmission unit, and further includes a microcomputer 9 that controls the internal operation of the strong motion meter.
[0003]
In the data processing unit 2, the absolute time is recorded by the internal clock 4 calibrated by the automatic calibration device 4 a (attached to the clock) based on the time signal of the radio 3, and the seismic waveform is stored in the IC card 5 for post-processing. This makes it easy to perform computer analysis. Reference numeral 3a denotes an antenna.
[0004]
The earthquake data recorded on the IC card can be called from a remote place via the telephone line 7.
And the uninterruptible power supply 20 is provided in order to operate the above strong motion meters.
[0005]
[Problems to be solved by the invention]
As described above, in the conventional strong motion seismometer, the internal clock 4 is calibrated by the time signal of the radio (terrestrial receiver) 3.
That is, on the broadcast wave of NHK, as shown in FIG. 5, 57 seconds: 440 Hz, 58 seconds: 440 Hz, 59 seconds: 440 Hz, 60 seconds (0 seconds): 880 Hz from 3 minutes before 0 / hour. A time signal consisting of each signal is transmitted.
[0006]
On the other hand, in the strong motion seismometer, the radio 3 receives this signal and calibrates the internal clock 4 by an automatic calibration device attached to the internal clock 4.
However, the time calibration using the NHK time signal cannot be performed in places where NHK radio waves are difficult to reach, and the NHK time signal is 0 minutes per hour, that is, every 60 minutes. There is a problem that the internal clock cannot be calibrated because there are few and the broadcast is interrupted at midnight.
[0007]
The present invention is intended to solve such a problem. A calibration signal that is the same as the NHK time signal is generated using a GPS signal transmitted from an artificial satellite, and this calibration signal is attached to an internal clock. An object of the present invention is to provide a strong motion seismometer equipped with an automatic time calibrating type internal clock which is transmitted to the automatic calibration apparatus and calibrated.
[0008]
[Means for Solving the Problems]
The present invention includes a ground sensor, a data processing unit capable of receiving seismic signals from the ground sensor, a microcomputer built in the data processing unit for controlling the internal operation of the strong motion meter, and the data processing unit. In the strong motion seismometer, which transmits an absolute time signal to an internal clock and is automatically calibrated by a time signal transmitted on the ground wave, the automatic calibration of the internal clock is formed based on a GPS signal. It is configured so that it can be performed by the same calibration signal as the time signal, and is used as a means for solving the problem.
[0009]
In the strong motion seismometer, an automatic calibration device is incorporated in the internal clock, while a receiver for the GPS signal is provided, which is the same as the time signal transmitted on the ground wave based on the GPS signal received by the receiver. A calibration signal generator capable of forming a calibration signal is provided, and the calibration signal generated by the calibration signal generator is transmitted to the automatic calibration device so that the internal clock can be automatically calibrated. As a means of solving problems.
[0010]
Further, in the strong motion seismometer, when the calibration signal generator receives a time signal for reporting 57 to 59 seconds of the GPS signal, a 440 Hz sound wave is formed in synchronization with the pulse signal at each time. When a time signal for notifying 60 seconds of the GPS signal is received, it is constituted by an electronic circuit that forms an 880 Hz sound wave in synchronization with the pulse signal at that time, and serves as a means for solving the problem.
[0011]
In the present invention, since the internal clock of the strong motion meter can be automatically calibrated by using the same calibration signal as the time signal signal (transmitted by terrestrial) generated based on the GPS signal, reception of terrestrial radio waves is possible. It is possible to automatically calibrate the internal clock even in an impossible area or time.
[0012]
The internal clock of the strong motion seismometer is originally configured to be automatically calibrated by a time signal transmitted by terrestrial waves, so a simple improvement of adding a GPS receiver and a calibration signal generator can Automatic calibration is possible.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
1 is a system diagram of the strong motion seismometer, FIG. 2 is a circuit diagram of the calibration signal generator, and FIG. 3 is the flowchart. In FIG. 1, the same reference numerals as those in FIG. 4 indicate substantially the same members.
[0014]
In FIG. 1, reference numeral 10 indicates a calibration signal generator for generating a signal for automatically calibrating the internal clock 4 (the same signal as the NHK time signal; hereinafter referred to as “calibration signal”). A GPS antenna 10a is connected to the signal generator 10 so that GPS signals are input.
[0015]
As shown in FIG. 2, the calibration signal generator 10 includes a GPS signal receiver 11, a CPU 12, a ROM 13, an input side interface 14, an output side interface 15, and a TTL (Transistor Transistor Logic circuit) 16. Calculations according to the flowchart of FIG. 3 are performed.
[0016]
That is, a signal (GPS signal) that is accurately transmitted every second from the artificial satellite is received, a signal (time signal) that indicates the time in the GPS signal is read, and this is a signal that indicates “57 seconds”. It is determined whether or not there is (step A1).
[0017]
When the time signal in the GPS signal is “57 seconds”, a 440 Hz signal (digital signal) is read from the ROM 13 in synchronization with the pulse signal at that time through the YES route (step A2).
[0018]
When the next GPS signal (after 1 second), that is, the time signal of “58 seconds” is received, the YES route is passed (step A3), and at the same time, the pulse signal at the time is received, and at the same time, the ROM 13 reads 440 Hz. Read the signal (digital signal). When a GPS signal including the next time signal of “59 seconds” is received, a 440 Hz signal (digital signal) is read from the ROM 13 in the same manner as described above.
[0019]
When the next GPS signal, that is, a GPS signal including a time signal of “60 seconds (0 seconds)” is received, an 880 Hz signal (digital signal) is read from the ROM 13 in the same manner as described above (step A4).
[0020]
Each digital signal of 440 Hz to 880 Hz read at the time of reception of each signal of 57 seconds to 60 seconds is converted into a sound wave (analog signal) of 440 Hz or 880 Hz by the TTL 16, and this is similar to the NHK time signal. The time signal, i.e., the calibration signal is formed, and this calibration signal is transmitted to the automatic calibration device 4 a attached to the internal timepiece 4.
[0021]
In the automatic calibration device 4a, the same processing as when the NHK time signal is received is performed, and the internal clock 4 is automatically calibrated.
Since an accurate second signal is transmitted every second from the artificial satellite, the GPS signal is used as the calibration signal of the internal clock, so that the time data of the internal clock can be kept highly accurate.
[0022]
In addition, since the internal clock of the strong motion meter can be automatically calibrated using the calibration signal formed based on the GPS signal, the internal clock can be automatically calibrated even in areas or times where terrestrial radio waves cannot be received. It becomes.
[0023]
Furthermore, the internal clock of the strong motion seismometer is configured to be automatically calibrated by the time signal transmitted from the ground wave, so a simple improvement of adding a GPS receiver and calibration signal generator automatically Configuration is possible.
In the above example, the calibration of the internal clock is performed every 60 seconds, but the program of the CPU 12 can be changed so that the calibration is performed, for example, every 60 minutes.
[0024]
【The invention's effect】
As described in detail above, according to the strong motion seismometer equipped with the automatic time calibration type internal clock of the present invention, the following effects or advantages can be obtained.
(1) Since the internal clock of the strong motion meter can be automatically calibrated using the same signal as the time signal transmitted on the ground wave formed based on the GPS signal, that is, a calibration signal, it is impossible to receive ground wave radio waves. It is possible to automatically calibrate the internal clock even in any region or time.
(2) The internal clock of the strong motion seismometer has a configuration that can be automatically calibrated by a time signal transmitted from the ground wave, so a simple improvement of adding a GPS receiver and a calibration signal generator, Automatic configuration is possible.
(3) Since an accurate second signal is transmitted every second from the artificial satellite, the GPS signal is used as the calibration signal of the internal clock, so that the time data of the internal clock can be kept highly accurate.
[Brief description of the drawings]
FIG. 1 is a system diagram of a strong motion seismometer equipped with an automatic time calibration type internal clock as one embodiment of the present invention.
FIG. 2 is a circuit diagram of the calibration signal generator.
FIG. 3 is an operational flowchart of the calibration signal generator.
FIG. 4 is a system diagram of a conventional strong motion seismometer.
FIG. 5 is an analysis diagram of a time signal in a normal terrestrial wave.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ground sensor 2 Data processing part 3 Radio 4 Internal clock 4a Automatic calibration apparatus 5 IC card 7 Telephone line 9 Microcomputer 10 Calibration signal generator 10a GPS signal receiving antenna 11 GPS signal receiver 12 CPU
13 ROM
14, 15 interface 16 TTL

Claims (3)

In a strong motion seismometer, a ground sensor, a data processing unit capable of receiving seismic signals from the ground sensor, a microcomputer built in the data processing unit for controlling the internal operation of the strong motion meter, and the data processing unit And an internal clock that is automatically calibrated by a time signal transmitted by terrestrial, the automatic calibration of the internal clock is the same as the time signal formed on the basis of the GPS signal. A strong seismometer equipped with an automatic time calibrating type internal clock, characterized in that it can be operated by a calibration signal. While the internal clock is equipped with an automatic calibration device, a receiver for the GPS signal is provided, and the same calibration signal as the time signal transmitted on the ground wave based on the GPS signal received by the receiver is provided. A calibration signal generator that can be formed is provided, and the calibration signal formed by the calibration signal generator is transmitted to the automatic calibration device so that the internal clock can be automatically calibrated. A strong seismometer comprising the automatic time calibration type internal clock according to claim 1, When the calibration signal generator receives a time signal that announces 57 to 59 seconds of the GPS signal, it generates a 440 Hz sound wave in synchronization with each pulse signal at that time and notifies the GPS signal of 60 seconds 3. A strong motion seismometer equipped with an automatic time calibrating internal clock according to claim 2, further comprising an electronic circuit that generates a sound wave of 880 Hz in synchronization with a pulse signal at the time when the signal is received.

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