Method and apparatus for generating a time signal

Abstract

A time signal generation system produces a reference time signal based on the signals transmitted by geostationary satellites, such as the satellites in the Wide Area Augmentation System (WAAS). A receiver in the system includes a directional antenna that is focused on the signals transmitted by the geostationary satellite. The antenna rejects multipath signals, and the receiver thus tracks the satellite signal directly, without having to compensate for multipath distortion. Once the receiver is tracking the code and carrier, the receiver decodes the transmitted data to recover timing information, as well as satellite orbital correction information and an ionospheric model, or table, transmitted by the satellite. The receiver then uses the decoded information and timing pulses provided in synchronism with the transmitted PRN code to produce a corrected timing signal. The timing signal is provided to drive a reference clock that produces a system time signal that is essentially as stable as the Cesium clock signals utilized by the WAAS system.

Dependencies are inferred from the claim text.