Navigation satellites act as artificial points of light in a modern analogue of celestial navigation. A receiver uses signals from several orbiting references to narrow its possible position, with additional well-placed signals improving the fix. Modern equipment may draw on GPS and Galileo rather than one constellation alone to increase the number of usable bearings. Precision matters both for efficient great-circle routing and for staying safely clear of hazards before an emergency avoidance manoeuvre is needed.
Notable Point · 40:12-45:09
Satellite navigation as artificial stars
Satellite constellations extend the logic of celestial fixes by providing many dependable points of bearing.