JPH1031083A - System and method of automatic correction for computer built-in watch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically correct a watch built in a personal computer, on the basis of the time data of signals sent from the global positioning system satellite. SOLUTION: A host computer 103 compares a time available from signals sent from a GPS satellite 101 with a time available from a built-in watch. The host computer 103 automatically corrects an error, if any, and synchronizes the built-in watch thereof with the time of the watch of the GPS by a second unit. Furthermore, a plurality of personal computers 107 connected to a network are capable of automatically correcting the built-in watches thereof through synchronization with the watch of the host computer 103 via a communication line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a system for automatically correcting a clock built in a computer. More specifically, the present invention relates to a system for automatically correcting a clock built in a computer by using time data included in a signal from a GPS satellite.

[0002]

2. Description of the Related Art With the development of microprocessor technology in recent years, personal computers (hereinafter, simply referred to as personal computers) have become widespread, and individuals have purchased hardware having processing capacity comparable to that of mainframes a while ago. And can be used. However, on the other hand, the development of microprocessors is rapid, and the shipment cycle of products is fast, so that maintenance of peripheral devices tends to be delayed, which has caused problems. As one example, a clock built into a personal computer, which should be accurate in nature, does not operate properly in some cases, and an accurate timekeeping is not performed.

In order to correct a computer built-in clock that is ahead or behind, for example, conventionally, a time signal service by telephone or the like is used, and a time signal from NTT is directly heard through a handset or the like while listening to the ear. Generally, the time is corrected by operating a personal computer.

[0004]

However, in the conventional correction of the clock using the time signal by telephone, the user of the personal computer must perform the operation individually, which is troublesome and manual operation. Is not always easy to secure. At present, the use of personal computer communication and the Internet has become widespread, and it is very common to use a personal computer, not as a stand-alone device, but as a part of a network configured through a telephone line or the like.
In such a situation, instead of the user manually adjusting the clock via a keyboard or the like while listening to the time signal of the phone with his ear as in the past, it is built into each personal computer terminal using a network. It would be useful to be able to collectively correct the clocks you have.

[0005] The present invention utilizes a network constituted by a large number of personal computers, and furthermore, a base for correcting time data contained in a signal from a GPS satellite used in a car navigation system or the like. The purpose of the present invention is to automatically correct a clock built in a personal computer by using it as reference data.

[0006]

For example, in a car navigation system using GPS, signals from a plurality of satellites are received, and a three-dimensional vehicle of a current vehicle is received based on a difference between arrival times of the signals. Determine the position. In the system according to the present invention, only the time component in the signal from the GPS satellite is used and used as a global time reference.

Therefore, it is not necessary to consider the difference between the arrival times of signals from a plurality of satellites, and it is sufficient to be able to receive signals from only one satellite. The receiving device may be installed, for example, near a window of a building where a host computer is installed. It is assumed that commercially available equipment is used for extracting signals from GPS satellites.
The computer receives a GPS satellite signal from a receiving device via a terminal of a general RS232C standard. The host computer does not need to be a special computer, but an ordinary personal computer is sufficient.

[0008] The host computer extracts data giving the Greenwich Mean Time from the received signal, and converts this data to Japan Standard Time by software installed in the host computer. Since the signal from the GPS satellite is sent every second, the time given by the signal is compared with the time by the clock built in the host computer at this timing, and if an error occurs, it is automatically corrected immediately. I do. Thus, the clock built in the host computer is always synchronized with the clock on the GPS satellite in seconds.

According to the present invention, a plurality of personal computers connected to the network can automatically correct the built-in clock by synchronizing with the clock of the host computer via the communication line.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The system of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram showing an outline of an automatic correction system for a computer built-in clock according to the present invention. The host computer 103, which functions as the center of the network for the system of the present invention, has a GPS
A signal from the satellite 101 is transmitted from the GPS receiver 102 to
It is received via the RS232C standard line. The host computer 103 uses its own built-in clock
Correct based on time data from satellites. A plurality of modems are connected to the host computer 103, and wait for an incoming call from a personal computer terminal (hereinafter, simply referred to as a terminal) 107 whose internal clock is to be corrected. The modems 104 and 106 to be used automatically correct an error caused by noise generated on a communication line, and are called an MNP modem or the like depending on a protocol to be followed.

A personal computer terminal 107 connected to a network including a host computer 103 is connected to a modem 10.
6 and communicates with the host computer 103 via the public telephone line 105 to synchronize the internal clock with the internal clock of the host computer 103. The communication line used may be not only a general telephone line but also a dedicated line,
ISDN may be used. Of course, in the case of ISDN, an appropriate communication device such as a terminal adapter is used instead of a modem.

FIG. 2 is a flowchart showing a clock correction process in the host computer 103. In step 200, the correction process starts, and in step 201, reception of a signal from a GPS satellite is confirmed. If it has been received, the process proceeds to step 202, where the host computer 1
The time of the clock built in the device 03 is compared with the time indicated by the GPS signal to check for an error.
If there is an error, the built-in clock is automatically corrected. As a result, the clock of the host computer 103 synchronizes with the atomic clock of the GPS satellite and performs accurate timekeeping. The time obtained in this manner is a reference for time correction by the system of the present invention.

In the personal computer terminal 107, when the user of the system according to the present invention corrects the built-in clock,
Various operating systems (DOS, WINDO)
WS3.1 or 95) is started. This software is the modem 1 built in or connected to the terminal 107.
06, requesting transmission to the host computer 103 via the public telephone line 105. When the host computer 103 confirms the incoming call from the terminal 107,
Automatically go off-hook. After the off-hook, the modem 104 on the host computer 103 executes authentication (negotiation) of connection with the other party's modem 106, and establishes a connection with the modem 106 on the terminal side in a mode for automatically correcting an error. Run. When the connection is complete,
The terminal software is transmitted to the host 103 from the terminal 10.
7 is transmitted. In the first message, a software management number and the like are set, and it is determined whether or not the connection is made by unauthorized use. In the case of unauthorized use, the line is immediately disconnected and on-hook is executed. For legitimate use, the host
The computer 103 sends a message message. After transmitting the message message, the host computer 103
After confirming the elapse of one second, a telegram in which the time is set is transmitted at one-second intervals. After receiving the message message, the terminal 107 corrects the built-in clock using the time message received at one-second intervals. Normally, the internal clock of the terminal is corrected by the first message, but for security, the host computer 107 transmits a plurality of messages. When the correction of the built-in clock is completed, a message message is displayed on the display of the personal computer terminal 107. Then, the line is disconnected, and the operation of the software ends.

FIG. 3 is a flowchart showing a communication process between the host computer 103 and the personal computer terminal 107. In step 300, the user of the terminal 107 starts a clock correction process. The terminal-side modem 106
In step 301, an incoming call is confirmed. Then,
Check the timeout and the reception of the station start in step 3
After performing steps 02 and 304, it is checked in step 305 whether there is an abnormality in the opening message. If there is no abnormality in the opening message, the answer is transmitted normally. After the communication between the host computer 103 and the personal computer terminal 107 is thus established, the clock of the host computer 103 and the personal computer terminal 107 are synchronized. In step 308, it is confirmed whether or not the time message is normally transmitted up to sequence 9, and if it has been transmitted, the line is hooked on (step 303). If it has not been transmitted, the line connection is confirmed in step 309, and if it has not been disconnected, it is confirmed in step 310 whether or not the line has been divided into seconds. Send a time message.

The telegram exchanged between the personal computer terminal 107 and the host computer 103 has a variable length and includes a control unit and an information unit. The control unit consists of 6 bytes. The first byte is fixed at 01h.
The next two bytes are assigned to the serial number of the message. The next two bytes have a length including the control part and the information part of the message. One subsequent byte is used as a message section.

FIG. 4 shows a clock correction process in the personal computer terminal 107. After the process starts in step 400, a call is made to the communication line in step 401. After confirming in step 402 and step 403 that the connection has been established without timeout, respectively, the station transmission is performed (step 404). In this case, the message from the personal computer terminal 107 to the host computer 103 is as follows:
The control sequence number is 1, the message segment is 00h,
The information section is up to 63 bytes. Further, it is confirmed that no timeout has occurred and that there is no abnormal response (steps 405 and 406), and a message is received. At this time, the host computer 103 sends the personal computer terminal 107
The control unit sequence number of the electronic message is 1. The message classification is 03h in the case of an abnormality such as an incorrect information section of the channel opening request from the personal computer terminal 107, and 02h in the case of normal. Thereafter, the message is within 4096 bytes. In step 406, it is checked whether the reception is normal, and after transmitting the abnormality of the start response, after 3 seconds, the host computer 103 transmits
The line is disconnected (step 411). Further, timeout and time reception are confirmed (steps 408 and 40).
After 9), the clock is corrected (step 41).
0). In the time message, the information part sequence number starts with 2 and ends with 9, and the message segment is 20h. After that,
This is a 14-byte time message. For example, if the time is 12:34:56 on June 20, 1996, 19960620
Expressed as a sequence of 123456 numbers.

[0017] Even after the first time message is transmitted, the time message is continuously transmitted every second in order to ensure clock correction. After transmitting the time telegram having the sequence number 9, the line is disconnected after waiting three seconds. If the disconnection of the line with the partner is detected during transmission of the time message, the line is also disconnected on the host side.

As described above, the clock built in the personal computer terminal 107 is automatically corrected by synchronizing with the atomic clock installed in the GPS satellite 101.

[0019]

According to the present invention, unlike the case where clock correction is manually performed based on a time signal from a telephone company as in the prior art, communication with the host computer 103 via a network using a public telephone line is performed. By sending and receiving signals,
The internal clock of the personal computer terminal 107 is automatically corrected based on the signal from the GPS satellite.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an outline of an automatic correction system for a computer built-in clock according to the present invention.

FIG. 2 is a flowchart showing a clock correction process in a host computer.

FIG. 3 shows a host computer 103 and a personal computer terminal 1
13 is a flowchart showing a communication process with the communication device 07.

FIG. 4 shows a clock correction process in the personal computer terminal 107.

Claims (2)

[Claims] 1. A system for automatically correcting a clock built in a computer terminal connected to a host computer via a network, wherein the system is connected to the host computer and receives a signal from a GPS satellite. Means for correcting a clock built in the host computer according to time data included in a signal from the GPS satellite, a clock built in the host computer, and a clock built in the computer terminal. Means for automatically correcting the built-in clock of the computer terminal by performing communication over the network and synchronizing the clock. 2. A method for automatically correcting a clock built in a computer terminal connected to a host computer via a network, comprising the steps of: receiving a signal from a GPS satellite; Correcting the clock built in the host computer according to the included time data; and synchronizing the clock built in the host computer and the clock built in the computer terminal by performing communication via the network. Automatically correcting the built-in clock of the computer terminal.