KR20020093295A - Method for synchronizing time data in transfer system - Google Patents

Abstract

PURPOSE: A method for synchronizing a time data in a transmitting system is provided to create data without an additional time coder and to send an accurate time synchronized data by implementing a data generation device based on a PC and a data synchronized part synchronized with Cs without amending additionally to generate a time data synchronized with a precise Cs atom clock in a sending system among time/frequency synchronized systems. CONSTITUTION: A method for synchronizing a time data in a transmitting system includes the steps of: transmitting a synchronizing output signal through an information communication network in a time code generator to generate a time data synchronized with a precise Cs atom clock; generating a subsequent frame data module of a data generator device(23) by using a synchronized timer in response to the transmitted synchronized output signal; storing by transmitting the data frame generated through the data generator device(23) to a baseband modem(26) with channel coding; inputting a predetermined reference clock to a digital processing phase locked loop(DPPLL) through the Cs atom clock(24) and transmitting the predetermined reference clock to the baseband modem(26) by generating a reference clock precisely synchronized by the inputted reference clock; and generating a synchronous time data which is synchronized by the data frame stored at the baseband modem(26) and the precisely synchronized reference clock.

Description

Method for synchronizing time data in transfer system

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for providing a precise clock using a geostationary satellite, and in particular, a computer for recording a time data synchronization method in a transmission system for synchronizing data with a reference clock in a transmission system and a program for realizing the method. The present invention relates to a recording medium which can be read by.

Currently, there are no known technical data on implementation methods for generating precise time-synchronized data. The Global Positioning System (GPS), which is currently in operation, uses a method in which the ground station corrects the time data synchronized by the atomic clock mounted on the satellite and transmits it as data.

Therefore, in the current technical field, a PC-based data generator and a data synchronization part synchronized with cesium can be generated without modifying a separate existing block to generate visual data synchronized with a precision cesium (Cs) atomic clock. A method for transmitting accurate and time-synchronized data is essential.

The present invention has been proposed to meet the above requirements, and cesium data generated from a PC-based data generator to generate time data synchronized with a precision cesium atomic clock in a transmission system of a time / frequency synchronization system. By implementing a module that transmits the transmission signal synchronized with the atomic clock in software without any hardware modification, the time data synchronization method for generating time data precisely synchronized with the reference clock in the transmission system and a program for realizing the method are recorded. Its purpose is to provide a computer readable recording medium.

1 is a configuration example of a synchronization system for time and frequency synchronization using a satellite to which the present invention is applied.

2 is a diagram illustrating an embodiment of a time data synchronization method in a transmission system according to the present invention.

3 is a process diagram between modules for achieving precise time synchronization in a time data synchronization method in a transmission system according to the present invention;

4 is an exemplary view of implementing a data generator according to the present invention.

* Explanation of symbols for the main parts of the drawings

110: transmitting device 120 ~ 12n: receiving device

130 ~ 13n: Integrity monitoring and correction device

The present invention for achieving the above object, in the time data synchronization method applied to the transmission system, in order to generate time data synchronized with the precision cesium atomic clock, the time code generator transmits a synchronous output signal through the information communication network A first step of making; Synchronizing a timer according to the transmitted synchronous output signal and generating a next frame data module of the data generator by using the same; A third step of channel coding the data frame generated by the data generator and transferring the data frame to a baseband modem for storage; A fourth step of inputting a predetermined reference clock to a digital processing phase locked loop (DPPLL) through the cesium atomic clock, generating a precisely synchronized reference clock using the input reference clock, and transmitting the same to the baseband modem; And a fifth step of generating a time-synchronized data signal using the data frame stored in the baseband modem and the precisely synchronized reference clock.

The present invention also provides a transmission system having a processor, comprising: a first function of transmitting a synchronous output signal through an information communication network in a time code generator to generate time data synchronized with a precision cesium atomic clock; A second function of synchronizing a timer according to the transmitted synchronous output signal and generating a next frame data module of the data generator by using the same; A third function of channel coding a data frame generated by the data generator and transferring the data frame to a baseband modem for storage; A fourth function of inputting a predetermined reference clock into a digital processing phase locked loop (DPPLL) through the cesium atomic clock, generating a precisely synchronized reference clock using the input reference clock, and transmitting the generated reference clock to the baseband modem; And a computer readable recording medium having recorded thereon a program for realizing a fifth function of generating a time synchronized data signal using the data frame stored in the baseband modem and the precisely synchronized reference clock.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is an exemplary configuration diagram of a synchronization system for time and frequency synchronization using a satellite to which the present invention is applied, and includes a transmitter 110, receivers 120-12n, and integrity monitoring and correction apparatus 130. 13 n).

The operation of the time and frequency synchronization system having such a structure is as follows.

First, the transmitter 110 generates high-precision time and frequency synchronization signals using atomic clocks, correction and integrity monitoring information, and satellite orbit information to transmit satellite orbit data, correction data, and time information to geostationary satellites. .

Then, the receivers 120 to 12n receive a signal transmitted through the geostationary satellite from the transmitter 101, which is delayed and distorted on the satellite link, and recovers a clock for high precision time and frequency synchronization, respectively.

In addition, the integrity monitoring and correction device (130 ~ 13n) measures the amount of delayed distortion on the satellite link in real time, and transmits this information back to the transmitter 101 in real time through the integrity monitoring to detect a sudden accident . In this case, the integrity monitoring and correction apparatus may be implemented in one or more numbers.

2 is a diagram illustrating an embodiment of a time data synchronization method in a transmission system according to the present invention.

As shown in FIG. 2, first, a PC clock (synchronous loop) 22 and data every minute through the Internet in a time code generator synchronized with KST generated by the Institute of Standards and Science (KST). The synchronous output signal is transmitted to a PC composed of the generator 23.

One minute, the update period, is virtual, and is affected by the hold over characteristic of the PC clock 22. That is, if the accuracy of the self-oscillator of the PC clock 22 is poor, the update cycle may be made faster, and in the case of good case, the update cycle may be delayed.

In the case of internet network synchronization, the synchronization can be achieved within about several ms although it is influenced by the latency characteristics of the internet network. However, dedicated lines can be used to be more precise and to avoid the effects of network characteristics. Therefore, in the present invention, a PC clock epoch as shown in FIG. 3 can be generated. Therefore, when the PC itself clock is synchronized, the frame data generation module of the data generator 23 is operated by using "WM_TIMER" in the window message.

Basically, since the length of the data frame is 1 second in the currently implemented data module, all the constituting data are implemented to generate data corresponding to the next 1 second. An embodiment of a data generating device generated for the present invention is shown in FIG. 4. As shown in FIG. 4, the current synchronized time is 16:46:27 seconds on March 19, 2001, and the frame to be transmitted is a data frame of 16:46:28 seconds on March 19, 2001, which is one second earlier. The data frame thus generated is channel coded and stored in an internal buffer of the baseband modem 26.

Here, the interface with the baseband is implemented through a universal asynchronous receiver transmitter (UART) port or a universal serial bus (USB) port that can be easily implemented on a PC. The data processing time inside the PC is considerably less than 1 second. Therefore, it is maintained through the delay time as shown in FIG. The cesium atomic clock 24 of the transmission system located in the transmission system now enters the 1 pps (1 second) clock and 10 MHz of the transmission into the Digital Processing Phase Locked Loop (DPPLL) 25. Here, the digital method generates a cesium atomic clock and a precisely synchronized reference system clock within 5 ns.

Since the DPPLL 25 includes a holdover mode operation block therein, the DPPLL 25 maintains its own performance for some time in the absence of the reference clock loop of the cesium atomic clock 24 of the temporary transmission system. Can be. Through this, the present invention synchronizes all functional blocks of the baseband modem 26. Conceptually, the 1pps output signal from the DPPLL 25 becomes an epoch signal indicating the start of transmission of data in the data buffer. In accordance with the 1pps output signal of the DPPLL 25, transmission of the next one-second frame data is started in the data buffer, so that a time-synchronized data signal can be generated. In addition to the data, all the functional blocks inside the baseband modem 26 such as the PN code generator are operated using the system clock output from the DPPLL 25 and a 1pps period.

Between the reference clock of the cesium atomic clock 24 of the transmission system and the Korea Standard Time 21 generated by the Institute of Standards and Science of FIG. 2, there are always various methods such as a time comparison method using a two-way satellite modem or a time comparison method using a GPS simultaneous comparison receiver. The technique is used to synchronize each other within a few ns. Rather than correcting the clock phase offset of the reference clock of the cesium atomic clock 24 of the direct transmission system, data about the clock phase offset can be simultaneously loaded into the frame data to be corrected at the receiver.

3 is a process diagram between modules for achieving precise time synchronization in a time data synchronization method in a transmission system according to the present invention.

As shown in FIG. 3, the KST and the transmission reference clock always obtain information about clock phase offsets from each other through constant monitoring through the above-described bidirectional satellite modem or GPS simultaneous comparison method. This information is obtained and processed by the Institute of Standards and Science or the present transmission system and transmitted to the data generator 23 in real time. This information also forms one of the transmitter data.

Looking only at the clock synchronization side, the data generated by the time code generator synchronized with the KST periodically updates the PC clock 22 inside the data generator periodically. The PC clock 22 generates a timer message every 1 second, and generates frame data of the next 1 second internally. The generated frame data is transmitted to the baseband modem 26 and stored in an internal buffer of the baseband modem 26. The baseband modem 26 sequentially transmits data of the next 1 second by the reference transmission clock. Such operation occurs periodically every second, and continuous data generation and transmission are performed.

The method of the present invention as described above may be implemented as a program and stored in a computer-readable recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.).

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible in the art without departing from the technical spirit of the present invention. It will be apparent to those of ordinary knowledge.

As described above, the present invention implements a PC-based data generator and a data synchronization part synchronized with cesium without modification to generate time data synchronized with a precision cesium atomic clock in a transmission system of the time / frequency synchronization system. As a result, data can be generated without the need for an additional time code, and there is an excellent effect of transmitting precise time-synchronized data.

Claims (6)

In the time data synchronization method applied to the transmission system, A first step of transmitting, by the time code generator, a synchronous output signal through the information communication network to generate time data synchronized with the precision cesium atomic clock; Synchronizing a timer according to the transmitted synchronous output signal and generating a next frame data module of the data generator by using the same; A third step of channel coding the data frame generated by the data generator and transferring the data frame to a baseband modem for storage; A fourth step of inputting a predetermined reference clock to a digital processing phase locked loop (DPPLL) through the cesium atomic clock, generating a precisely synchronized reference clock using the input reference clock, and transmitting the same to the baseband modem; And A fifth step of generating a time-synchronized data signal using the data frame stored in the baseband modem and the precisely synchronized reference clock; Time data synchronization method in the transmission system comprising a. The method of claim 1, The DPPLL is, And a holdover mode operation block therein to maintain performance for a predetermined time in the absence of a temporary reference clock loop. The method of claim 1, The time code generator, A method of synchronizing time data in a transmission system, characterized by periodically updating a PC clock inside a data generator. The method of claim 3, wherein The PC clock is, A timer message is generated every 1 second, and frame data of the next 1 second is generated internally based on this, and the generated frame data is transmitted to the baseband modem to be stored in a buffer inside the baseband modem. Method of synchronizing visual data in a transmission system. The method according to any one of claims 1 to 4, Inside the baseband modem, A method of synchronizing time data in a transmission system, characterized by starting transmission of data of the next 1 second sequentially by a reference transmission clock to generate periodically every second, and to generate continuous data for transmission. In a transmission system equipped with a processor, A first function of transmitting a synchronous output signal from the time code generator through the information communication network to generate time data synchronized with the precision cesium atomic clock; A second function of synchronizing a timer according to the transmitted synchronous output signal and generating a next frame data module of the data generator by using the same; A third function of channel coding a data frame generated by the data generator and transferring the data frame to a baseband modem for storage; A fourth function of inputting a predetermined reference clock into a digital processing phase locked loop (DPPLL) through the cesium atomic clock, generating a precisely synchronized reference clock using the input reference clock, and transmitting the generated reference clock to the baseband modem; And A fifth function of generating a time-synchronized data signal using the data frame stored in the baseband modem and the precisely synchronized reference clock; A computer-readable recording medium having recorded thereon a program for realizing this.