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The Satellite Clock | GEOG 862: GPS and GNSS for Geospatial Professionals

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One of the largest errors can be attributed to the satellite clock bias. It can be quite large, especially if the broadcast clock correction is not used by the receiver to bring the time signal acquired from a satellite’s onboard clock in line with GPS time. As time is a critical component in the functioning of GPS, it is important to look closely at the principles behind this bias. The onboard satellite clocks are independent of one another. While GPS time itself is designed to be kept within one microsecond, 1 µsec or one-millionth of a second, of UTC, excepting leap seconds, the satellite clocks can be allowed to drift up to a millisecond, 1 msec or one-thousandth of a second, from GPS time. They are allowed to drift within this tolerance because the Control Segment doesn't want to constantly tweak the clocks, as this would cause the clocks to deteriorate more rapidly. Although the GPS satellites have been robust, I think it's fair to say that the clocks are one of their more fragi

The Satellite Clock Bias, dt Cesium Frequency Standard (Clock) Source: National Air and Space Museum, Smithsonian Institution. One of the largest errors can be attributed to the satellite clock bias. It can be quite large, especially if the broadcast clock correction is not used by the receiver to bring the time signal acquired from a satellite’s onboard clock in line with GPS time. As time is a critical component in the functioning of GPS, it is important to look closely at the principles behind this bias. The onboard satellite clocks are independent of one another. While GPS time itself is d

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