THIS MONTH MARKS the 25th anniversary of the launch of the first of the modern fleet of GPS satellites.
GPS and predecessor systems have existed since the 1940s. That timing is significant, because in many ways the history of satellite navigation is the history of the Cold War.
The launch of Sputnik in 1957, the first salvo of the Space Race, itself a product of the Cold War, started to get scientists wondering, "If it can beep... what else can it do?" They theorised that the Doppler Effect of the signals as they moved closer and further away from their earthbound receivers could hold the key to something interesting.
Fast forward to the '80s, and although a GPS system had been inaugurated in 1973 it was highly secretive and strictly the preserve of the US military. This new NAVSTAR GPS network was the result of a pledge by Ronald Reagan who, during his presidency, agreed to open the system to civilian use following the downing of a Korean Airlines flight by the Russian military in 1983 after the pilot mistakenly strayed into Russian airspace, with the loss of 269 lives.
That tragedy was simultaneously both one of the biggest stories of the Cold War and also the start of a revolution in the way we navigate. At a stroke, even those with no discernable sense of direction could find their way. Less than a decade later, the completed GPS system got its first field test, as the Bush administration used it extensively in military operations during the first Gulf War.
The next big milestone came in 2000, when Bill Clinton made the decision to switch off the "blurring" feature that prevented civilians from using GPS precisely, and so rather than being limited to 100m accuracy, the GPS system could tell your location within five metres.
This was a brave move and a symbol of the thaw in international relations. Of course, civil liberties groups had opposed more accurate position location, but this more precise positioning was essential for GPS to live up to its full potential and began the widespread adoption of GPS technology.
Satnav units for vehicles became affordable within five years, while mobile phones became portable tracking devices enabling a range of new functionalities, much of which are integral to what smartphones make possible.
Our societal dependence on the GPS system has, some say, changed our brains - but it has also changed our relationships. No longer do couples drive around completely lost, blaming each other for their lack of map reading skills. The electronic satnav passenger has that covered now.
Or at least usually. With road systems changing all the time, there are stories of people who drove into rivers trying to find bridges that didn't exist because, although the GPS system has been gifted to the world, satnav systems are commercial and in most cases, if you want accuracy, it will cost you.
There are exceptions of course. It would be daft not to mention Google Maps, but perhaps more memorable was Apple's embarrasing replacement that labeled an entire city as a hospital, had huge swathes of missing colour, and in one case marked a town 43 miles off course in the middle of the Australian outback.
Add to that some 'interesting' topography that M.C. Esher would have been proud of, and you have one of the more colourful stories in the recent history of GPS. When Apple executive Scott Forstall refused to sign a public apology for the Apple Maps debacle, he was summarily dismissed.
So, as we reach the end of the first quarter century of the GPS system, what does the future hold? Later this year, the first GPS Block IIIA satellite will be launched as part of a rolling programme to upgrade the system, some of whose satellites are now 22 years old, which is a long time for a satellite.
Given that the failure of the system would render millions of devices useless, not to mention dangerous, this isn't a vanity project for the US, but rather a huge responsibility.
At the same time, there are a number of rival systems being established. GLONASS, the Russian equivalent of GPS was completed in 2004, and the European Galileo system is due to roll out this year to go into full operation by 2019. The Chinese COMPASS system will be with us by 2020, while several other countries are working on their own regional system.
At a time when international relations are somewhat better than they were at the launch of the original NAVSTAR service, it seems odd that so many of these rival services are considered necessary, and it serves as a reminder that however nice it is to tag your Instagram photos with locations, the real uses of GPS are for military operations and surveillance, both overseas and, at least potentially, domestically. µ