Base site and method for GPS-based regional time synchronization
First Claim
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1. A method for GPS-based regional time synchronization comprising:
- receiving, at a master site, information from a GPS satellite that indicates a position of the satellite and a satellite time-of-day;
determining, using the position of the satellite and a pre-determined position of the master site, a time-of-day error value that represents a difference between the satellite time-of-day, adjusted for a transit time of the information, and a corresponding master site time-of-day as reported by a master site, nanosecond-accurate clock; and
broadcasting to at least one slave site an indication of the time-of-day error value and the corresponding master site time-of-day.
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Abstract
To address the need for an apparatus and method of economically synchronizing base sites (110-113) in wireless communication systems, the present invention provides a GPS-based solution for synchronizing slave sites (111-113) to a regional master site (110). In general, the master site reports to the slave sites information indicating the timing variance of GPS satellites (101-105). The slave sites then use this information in combination with information they collect from the same satellites to periodically resynchronize their clocks to the master clock.
25 Citations
18 Claims
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1. A method for GPS-based regional time synchronization comprising:
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receiving, at a master site, information from a GPS satellite that indicates a position of the satellite and a satellite time-of-day;
determining, using the position of the satellite and a pre-determined position of the master site, a time-of-day error value that represents a difference between the satellite time-of-day, adjusted for a transit time of the information, and a corresponding master site time-of-day as reported by a master site, nanosecond-accurate clock; and
broadcasting to at least one slave site an indication of the time-of-day error value and the corresponding master site time-of-day. - View Dependent Claims (2, 3, 4, 5)
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6. A method for GPS-based regional time synchronization comprising:
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receiving, at a slave site and at a time indicated by a slave site clock, information from a GPS satellite that indicates a position of the satellite and a first satellite time-of-day;
storing information that indicates the time indicated by the slave site clock and how the time indicated by the slave site clock differs from the satellite time-of-day;
receiving, at the slave site, an indication of a time-of-day error value and a corresponding master site time-of-day, as reported by a master site, nanosecond-accurate clock, wherein the time-of-day error value represents a difference between a second satellite time-of-day, adjusted for a transit time to the master site, and the corresponding master site time-of-day;
determining a clock correction value for the slave site using the stored information, the time-of-day error value, and the corresponding master site time-of-day; and
synchronizing a slave site clock with the master site using the clock correction value. - View Dependent Claims (7, 8, 9, 10, 11)
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12. A base site comprising:
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a GPS receiver arranged to receive information from a GPS satellite that indicates a position of the satellite and a first satellite time-of-day;
a clock coupled to the GPS receiver that indicates a time at which the GPS receiver received the information;
a clock controller, coupled to the GPS receiver and the clock, arranged to store information that indicates the time indicated by the clock and how the time indicated by the clock differs from the first satellite time-of-day, further arranged to receive an indication of a time-of-day error value and a corresponding master site time-of-day, as reported by a master site, nanosecond-accurate clock, wherein the time-of-day error value represents a difference between a second satellite time-of-day, adjusted for a transit time to the master site, and the corresponding master site time-of-day, further arranged to determine a clock correction value using the stored information, the time-of-day error value, and the corresponding master site time-of-day, and further arranged to synchronize the clock with the master site, nanosecond-accurate clock using the clock correction value. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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Specification