25 years ago: Bill Clinton releases GPS

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With some developments, the effects only become visible at a distance: when the then US President Bill Clinton ordered on 1 May 2000 that the civilian signal of the US Global Positioning System (GPS) satellite navigation system should be just as accurate as the military signal, he initiated a development that has fundamentally revolutionized navigation. 25 years later, the way we find our way to a destination has changed fundamentally as a result. New applications, from geocaching to geotagging, have emerged.

"I am pleased to announce today that the United States will cease the deliberate degradation of Global Positioning System (GPS) signals available to the public beginning at midnight tonight," Clinton said. "This means that civilian GPS users will be able to determine their location up to ten times more accurately than before."

Until then, the US military, as the operator of the system, had deliberately jammed the signal for civilian users so that their position could only be determined with an accuracy of around 100 meters. This was to prevent an enemy from using the system for their own purposes, for navigation or to target guided missiles.

GPS has become commonplace

Since the abolition of this "selective availability", the civilian GPS signal has an accuracy of 10 to 15 meters and has become an integral part of our daily lives. Practically every smartphone on the market is also a receiver for several Global Navigation Satellite Systems (GNSS) – because GPS has long had company.

Thick road atlases, maps or city plans have long been a thing of the past. Nowadays, anyone setting off on a journey and needing to find their way through the countryside or an unfamiliar city enters their destination into a navigation system or smartphone app and is guided electronically to their destination.

The respective system knows the quickest, shortest, most attractive or most energy-efficient way to get there. There is no need to leaf through an atlas or fiddle with hiking maps or unwieldy folding maps.

A device needs contact with four satellites

To do this, the device must receive a signal from at least four of the 30 or so satellites currently available. The signal contains the position of the satellite as well as the transmission time - each GPS satellite has a very precise clock. The receiving device, such as a smartphone, calculates its position from the signal propagation times.

Traffic jams, roadworks and other traffic obstructions are avoided where possible, and this is even more reliable and up-to-date than the traffic news that is broadcast on the radio every half hour – Thanks to GPS: the major map providers such as Google receive movement data from their customers. If a large number of devices on a road send hardly any changes in position, there is a traffic jam. The road is colored red on the digital map.

Companies equip their vehicle fleets with GPS trackers. This allows them to see where each vehicle is at any given time – and find it again if it has been stolen, for example. Above all, it is also possible to predict when a transport or long-distance train will reach its destination.

On the water, GPS makes navigation considerably easier for sailors and motorboat drivers. It is true that paper charts still have to be on board, at least on German waters. However, the standard leisure sailor no longer determines his position using beacons, landmarks or the height of the stars, but electronically. In the meantime, tablets and smartphones are likely to increasingly replace the often very expensive navigation devices known as chart plotters.