Time synchronization apparatus and a method thereof using a global positioning system of a satellite
First Claim
1. A time synchronization apparatus using a global positioning system of a satellite receiving a 1 pps signal from the satellite, comprising:
- an oscillator for generating an oscillating frequency signal compatible with a global positioning system of a satellite;
a counter for generating an internal 1 pps by counting the oscillating frequency of the oscillator;
a comparator for outputting a phase difference signal by comparing a phase of the 1 pps signal received by the global positioning system and the internal 1 pps outputted from the counter;
a first controller for phase correcting the internal 1 pps outputted from the counter based on said phase difference signal;
a second controller for correcting the phase difference between the output frequency of the first controller and the oscillating frequency signal; and
a microprocessor for providing the phase difference signal outputted from the comparator to the first and second controllers for phase difference corrections, and for outputting a frequency error value to the oscillator for correcting the frequency of the oscillating frequency signal on the basis of the GPS 1 pps signal.
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Abstract
A time synchronization apparatus and a method using a GPS (Global Positioning System) of a satellite. An oscillator oscillates a frequency required for a Global Positioning System of a satellite. A counter generates an internal 1 pps by counting the oscillating frequency of the oscillator. A comparator outputs a phase difference by comparing the phase of the internal 1 pps outputted from the counter and the phase of the 1 pps signal received by the Global Positioning System. A buffer stores the phase difference comparison output of the comparator. A first controller corrects the phase difference of the internal 1 pps outputted from the counter. A second controller corrects an oscillating frequency outputted from the oscillator and the phase difference of the output frequency of the first controller. A microprocessor synchronizes time using the tracing state signals of the Global Positioning System detected from the Global Positioning System and the phase difference comparison output stored in the buffer and for providing the phase difference correction signals to the first controller and the second controller for the correction of the phase difference and for outputting the frequency error value. A digital/analog converter converts the error value outputted from the microprocessor unit into the digital/analog signals and transmits the converted signals to the operating control signals of the oscillator for adjusting the oscillating frequency of the oscillator.
94 Citations
8 Claims
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1. A time synchronization apparatus using a global positioning system of a satellite receiving a 1 pps signal from the satellite, comprising:
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an oscillator for generating an oscillating frequency signal compatible with a global positioning system of a satellite; a counter for generating an internal 1 pps by counting the oscillating frequency of the oscillator; a comparator for outputting a phase difference signal by comparing a phase of the 1 pps signal received by the global positioning system and the internal 1 pps outputted from the counter; a first controller for phase correcting the internal 1 pps outputted from the counter based on said phase difference signal; a second controller for correcting the phase difference between the output frequency of the first controller and the oscillating frequency signal; and a microprocessor for providing the phase difference signal outputted from the comparator to the first and second controllers for phase difference corrections, and for outputting a frequency error value to the oscillator for correcting the frequency of the oscillating frequency signal on the basis of the GPS 1 pps signal. - View Dependent Claims (2, 3, 4, 5)
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6. The time synchronization method using a global positioning system of a satellite, comprising the steps of:
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a first step of detecting whether a global positioning system tracing state exists and for generating a global positioning system 1 pps; a second step of oscillating at a frequency required for the global positioning system and for generating an internal 1 pps from an oscillating frequency; a third step of comparing a phase difference of the internal 1 pps and the global positioning system 1 pps; a fourth step of computing the phase difference value compared at the third step when the first step detects the global positioning system tracing state and for computing an average value of the phase difference; and a fifth step of correcting a phase error using the average value of the phase difference from the fourth step and for adjusting the frequency oscillated from the second step. - View Dependent Claims (7, 8)
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Specification