JP3008196B2 - Time control system - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a time control system for controlling a plurality of devices installed in a distributed manner in synchronization with each other, and more particularly to a time control system of a dependent synchronization system.

(Prior art) In the ground control equipment of a rocket launch site, a plurality of devices such as a control station, a launch pad, and a tracking device are dispersedly arranged. Control is being performed. For this purpose, the synchronization systems between the time signal generators in each device can be roughly classified into three types: an independent synchronization system, a dependent synchronization system, and a mutual synchronization system.

The independent synchronization system is a system in which each device operates completely independently and does not have any special means for synchronizing with each other. For this reason, a time generator having a high-precision atomic oscillator such as cesium or rubidium must be installed in each device, and there is a disadvantage that the whole system becomes very expensive.

On the other hand, the mutual synchronization method is a method of synchronizing by mutually sending and adjusting the time signals generated by the respective devices, so that even if the accuracy of the time generation device of each device is low, the overall system is high. Accurate time information can be obtained. However, there is a drawback that the operation is complicated, and that when one time generating device fails, the influence is exerted on the entire system.

On the other hand, the slave synchronization method establishes a master-slave relationship between the devices, and the slave time device extracts a time signal from the master time device and drives the time generation device of the own station in synchronization with the time signal. Therefore, a high-accuracy atomic oscillator is required for the master station time apparatus serving as a core, but a relatively low-accuracy inexpensive oscillator may be used for the slave station time apparatus. It is advantageous in terms of aspect. In the event of a failure of the working time signal, the owner is switched, and if the time signal is completely interrupted, the transmitter of that station is self-running and independent of other areas, minimizing the effects of failure. .

Therefore, from the above two advantages, the synchronization method generally uses the dependent synchronization method.

FIG. 3 is a configuration diagram of a time control system according to a conventional slave synchronization system. In the figure, reference numeral A denotes a master station time device, and a high-precision time signal generated by the master station time device A is transmitted to a plurality of slave station time devices B1 to Bn via a transmission line 9, and the slave station time devices B1 to Bn. In Bn, the generated time signal is synchronized with the time signal from the master station time device A to obtain a highly accurate time signal equivalent to that of the master station time device.

Here, the master station time apparatus A generally has two time generators 1 and 14, and adopts a high-precision atomic oscillator such as cesium or rubidium as a transmitter built in the time generators 1 and 14. I have. Each of the time generators 1, 14 is a switch 4
Connected to the modem 15.

On the other hand, the subordinate time device B1 generally has one time generating device 5, and a relatively low-precision oscillator such as a crystal oscillator is used as the oscillator incorporated in the time generating device 5. The time generator 5 is connected to the modem 16, and the other time generators B2 to Bn have the same configuration and connection.

This system operates as follows. That is, one of the time generating devices 1 and 14 of the master station time device A does not stop operating, and even if one stops operating due to maintenance, inspection, or failure, the other always operates. The time generator 1 or 14
Generates a time signal, and switches the changeover switch 4 to the side of the operating time generating device, whereby the time signal generated by the time generating device 1 or 14 is modulated by the modem 15, and transmitted to the modem via the transmission line 9. Enter 16 The time signal is demodulated by the modem 16, and the time generator 5 generates a time signal in synchronization with the time signal.

However, the conventional time control system described above has the following disadvantages.

That is, in the slave synchronization system, the slave station time devices B1 to Bn extract the time signal from the master station time device A and generate their own time signal in synchronization with the time signal. Requires an operation mode with almost no operation suspension, and the main station needs a spare time generation device in preparation for a failure of the main station time apparatus A or maintenance and inspection of the main station. For this reason, there is a problem that the equipment cost is high, and a floor space and power consumption are increased.

When the master station time device A is operated again after the operation is stopped,
The correct time cannot be generated by simply turning on the power, and the time must be reset. That is, a correct time is generated only after the time is calibrated using an external standard signal as a reference signal. Here, JJY or NTT time signal is used as a standard signal, but JJY is a simple clock and does not include time information. NTT time signal has an accuracy of several milliseconds and it is difficult to obtain an accurate time.

(Object of the Invention) The present invention has been made in order to solve the problems of the conventional time control system as described above, and freely stops operation of the master station time device without impairing the reliability of the entire time control system. It is an object of the present invention to provide a time control system that enables re-operation and reduces the equipment cost of a main station time device, floor space, and power consumption.

(Summary of the Invention) In order to achieve this object, the present invention has the following configuration.

That is, in the time control system of the slave synchronization method, if necessary, some or all of the time signals generated by the master station time device in the slave station time device are monitored, and a likely time is determined based on the time signal. By using the time information, the time signal generated by the master station time device can be easily corrected without referring to an external standard time, or the time signal of the master station time device can be synchronized with the time signal of the slave station time device. Configure to set.

(Example) Hereinafter, the present invention will be described in detail based on an illustrated example.

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

In the figure, reference numeral A denotes a master station time device, which transmits a high-precision time signal of the master station time device A to a plurality of slave station time devices B1 to Bn via a transmission line 9, and outputs the slave station time devices B1 to Bn.
Bn uses the time signal generated by the
By synchronizing with a signal from the master station, a highly accurate time signal equivalent to that of the master station time device A is obtained.

Here, the time device A includes one time generating device 1 and employs a high-precision atomic transmitter such as cesium or rubidium as a transmitter built in the time generating device 1.
The time generator 1 is connected to a modem 2 and a comparator 3.
Model 2 comprises a modulator and a demodulator, each of which is connected to a changeover switch 4.

On the other hand, each of the slave station time devices B1 to Bn comprises a time generating device 5, a modem 6, a comparator 7, and a changeover switch 8 like the master station. The modem 2 of the master station time unit A and the modem 6 of the slave station time unit B1 are connected via changeover switches 4, 8 and a transmission line 9. Similarly, slave station time device B2
Through Bn are connected to the master station time device A.

This system operates as follows. That is, the time signal generated by the time generating device 1 of the master station time device A is modulated by the modem 2 and transmitted to the modem 6 of the slave station time devices B1 to Bn via the changeover switch 4 and the transmission line 9.

The slave station time devices B1 to Bn compare the time signal demodulated by the modem 6 with the time signal generated by the time generator 5 by the comparator 7, and synchronize the time generator 5 with the time generator 1 of the master station. Drive.

Further, the master station time device A is occasionally replaced by the slave station time devices B1 to Bn.
And the time signal generated by the time generator 5 is received, the time signal is compared with the time signal generated by the time generator 1 by the comparator 3, and the time generated by the slave station time devices B1 to Bn is calculated. Monitor for accuracy.

On the other hand, when the operation of the master station time device A is stopped for maintenance and inspection, the switch 4 of the master station time device A is switched to the receiving side so as to avoid sending an erroneous time signal to the slave station devices B1 to Bn. I do.

During this time, the slave station time device runs on its own and is synchronized independently with other slave station time devices. The accuracy of the time generated by the time generator of the slave station time device is two digits lower than the time generated by the master station time device, but is reliable for a short period. That is, since the time required to shift by one clock is approximately one day, a sufficiently accurate time signal is generated for about half a day.

Next, when the master station time device A is re-operated, the master station time device A is switched to the slave station time device at the same time as the power supply of the master station time device A is turned on.
Command signals are sequentially sent to B1 to Bn, the time code of the slave time unit is demodulated by the modem 2, and the time signal of the slave time units B1 to Bn is majority-compared by the comparator 3 to determine a probable time. The time generator 1 is driven.

In this way, by using this method, it becomes possible to freely stop and restart the master station time device without impairing the reliability of the entire time control system. That is, accurate time calibration can be easily performed without the need for a spare time generating device or an external standard signal, which are conventionally required when the master station time device is operated again.

Further, since only one time generating device is required for the master station time device, the equipment cost of the master station time device can be reduced, floor space can be reduced, and power consumption can be reduced.

 The present invention may be modified as follows.

That is, in the above embodiment, the master station time device and the slave station time device have the same functional configuration except for the comparator, and the function of the comparator of the slave station time device is changed to the function of the comparator of the master station time device. The master station time device and the slave station time device have the same functional configuration. By making some of the slave time units have the same functional configuration as the master time unit, a plurality of master time units are provided, but the function of the comparator can be easily changed only by changing the software. Therefore, the reliability of the system can be further improved without increasing the equipment cost, floor space, and power consumption.

 The present invention may also be modified as follows.

That is, wireless may be used instead of connecting the master station time device and the slave station time device via a transmission line.

FIG. 2 is a block diagram of a modified embodiment of the present invention in which signals are transmitted and received between a master station and a slave station by radio.
In this example, a transceiver is provided instead of a modem, and an antenna is provided instead of a transmission line, and the operation is the same as that of the above-described embodiment.

(Effects of the Invention) As described above, the time control system according to the present invention is a time control system of the slave synchronization system, in which some or all of the time signals generated in the slave time device by the master time device as necessary. Monitor, determine a likely time based on the time signal, and easily correct the time signal generated by the master station time device without referring to an external standard time by using the time information, or Since the time signal of the master station time device is set in synchronization with the time signal of the slave station time device, the master station time device can be freely stopped and restarted without deteriorating the reliability of the entire system. In addition, since only one time generating device is required for the master station time device, the equipment cost of the master station time device is reduced, and floor space and power consumption are significantly reduced. effective.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing a modified embodiment of the present invention, and FIG. 3 is a block diagram of a conventional time control system of a dependent synchronization system. A: master station time unit, B1, B2,... Bn: slave station time unit, 1,
5… Time generator, 2,6… Modem, 3,7… Comparator,
4,8 ... changeover switch, 9 ... transmission line, 10,11 ...
… Transceiver, 12,13 …… Antenna

Claims (1)

(57) [Claims] 1. A time control system of a slave synchronization system for transmitting a time signal from a master station time device to a plurality of slave time devices, and generating a time in synchronization with the time signal from the master station time device. In the above, if necessary, the master station time device monitors some or all of the time signals generated by the slave station time device, and determines the time to be accurate by majority comparison of the time signals. A time control system, wherein the time signal generated by the master station time device is corrected using the time information, or the time signal of the master station time device is set in synchronization with the time signal of the slave station time device. .