The impact on GPS itself is negligible -the system's observation/ephemeris system adjusts for this sort of thing (ie: the change in Earth's rotation speed). One possible problem with a quake shifting land masses around is simply that your electronic or paper map has just become obsolete. The coordinates from the magic box are still correct, but that trail you're attempting to follow has moved.
GPS satellites are constantly monitored from ground observation stations (Navstar's land segment). These observations are used to create and later update the ephemeris information. Your GPS receiver uses its most recent ephemeris to convert ranges to the satellites into a geodetic coordinate (lat/lon).
Really, GPS should be able to deal with a minor change in rotation speed without any glitch. The land-based observations are used to adjust the ephemeris for the sat's actual position relative to ground control -this is typical. This information is then sent to the receivers from the satellites.
What we will see is that datums that people have been equating with their GPS obervations (ie: the WGS 84 ellipsoid) may become obsolete more quickly. Software developers are going to have to make the jump to a more correct GPS datum (ITRF?).
Of course, for the geosychonous satellites (of which, GPS is not) there may be issues.
/geodesy geek
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The impact on GPS itself is negligible -the system's observation/ephemeris system adjusts for this sort of thing (ie: the change in Earth's rotation speed).
One possible problem with a quake shifting land masses around is simply that your electronic or paper map has just become obsolete. The coordinates from the magic box are still correct, but that trail you're attempting to follow has moved.
GPS satellites are constantly monitored from ground observation stations (Navstar's land segment). These observations are used to create and later update the ephemeris information. Your GPS receiver uses its most recent ephemeris to convert ranges to the satellites into a geodetic coordinate (lat/lon).
/geodesy geek
Really, GPS should be able to deal with a minor change in rotation speed without any glitch. The land-based observations are used to adjust the ephemeris for the sat's actual position relative to ground control -this is typical. This information is then sent to the receivers from the satellites.
What we will see is that datums that people have been equating with their GPS obervations (ie: the WGS 84 ellipsoid) may become obsolete more quickly. Software developers are going to have to make the jump to a more correct GPS datum (ITRF?).
Of course, for the geosychonous satellites (of which, GPS is not) there may be issues.