Global navigation satellite systems

node

The collective name for the satellite constellations that broadcast position and time: the American GPS, the Russian GLONASS, the European Galileo and the Chinese BeiDou, together with regional augmentations such as Japan's QZSS and India's NavIC. Each works the same way — a receiver measures the arrival time of signals from four or more satellites carrying atomic clocks, and solves simultaneously for three position coordinates and its own clock error. Economically it is the strangest large business in space, because it is not a business. The constellations are built, launched and operated by states at public expense and the civil signal is free at the point of use, with no metering, no subscription and no contract between the operator and the user. All measured revenue is therefore downstream: receiver chipsets, devices, augmentation services and applications. On the industry's own accounting that downstream figure runs to hundreds of billions of euros a year, which makes GNSS simultaneously the most economically consequential space system in existence and one that appears on no operator's income statement. Not a place — the constellations occupy medium Earth orbit.

A node is not a place. Drawing it on a map would assert something about the world that no stored fact supports.