Physics · Ch 10 — Communication Systems
GLOBAL POSITIONING SYSTEM
GLOBAL POSITIONING SYSTEM
GPS stands for Global Positioning System -- a global navigation satellite system that provides geolocation (a precise position) and accurate time information to a GPS receiver anywhere on or near the surface of the Earth. The system works with the assistance of a whole network of orbiting satellites: each satellite continuously broadcasts a precise signal, very much like an ordinary radio signal, and these location-carrying signals are picked up by a low-cost receiving aerial, which then passes them on to be translated by the GPS software. That software is able to recognise which satellites it is receiving, work out where each one is, and calculate the time each satellite's signal took to arrive; by processing this data from several satellites at once, the software can estimate the receiver's own precise location. GPS is widely useful across many fields: in fleet vehicle management, for tracking the position of cars, trucks and buses; in wildlife management, …
What this figure shows. A diagram of the Earth at the centre, surrounded by multiple orbital paths on which a number of GPS satellites are shown positioned at different points, spread out so that from almost any point on or near the Earth's surface several satellites are simultaneously visible above the horizon at once. The figure conveys the essential engineering idea behind GPS: it is not one single satellite broadcasting a signal, but a whole constellation deliberately arranged so that a receiver anywhere on Earth can typically pick up signals from several satellites at the same time, which is exactly what the GPS software needs in order to tria …