The History Of GPS: From Military Communication To Navigation In Your Pocket

GPS has definitely made life easier. Whether we're checking in with friends at our favourite hotspots or heading off on a road trip with no fear of getting lost, satellite signals are responsible for our connected world.

Satellite navigation has come a long way from its humble beginnings in the 1950's. Nowadays we all have it in our pockets, but that's not always been the case.

Sputnik started it

When the USSR launched Sputnik in 1957, they thought they were simply striking a blow against America in the Cold War. Little did they know they were also paving the way for GPS technology. The brains at MIT noticed that the Doppler effect caused Sputnik's satellite frequencies to change as it approached and left.

This gave them an idea: they could track satellites from the ground by measuring the frequencies. More importantly, receivers based on the ground could have their location tracked based on how far they were from the satellite.

The military sat up and took notice

The potential for using GPS technology for military satellite communications was obvious, and over the next few years America's military organisations started to develop their own systems.

The Navy were the first to pioneer GPS technology, and in 1959 launched their TRANSIT system to locate submarines. It was pretty slow going at first. With only six satellites in the sky, it could be hours before any signals reached the submarines.

Four years later The Aerospace Corporation proposed a system of satellites that sent continuous signals. This would be able to track fast moving cars, 'planes, and boats as they sped along. This was the beginning of GPS as we know it, with receivers placed in the vehicles sending spot-on coordinates based on the satellite radio signals.

Eleven years later, the military was ready to launch the first satellite to test their NAVSTAR system. By the mid-80's the system became known simply as "the GPS System". The new satellites were equipped with special features, such as super accurate atomic clocks and sensors that could sense the launch of nuclear weapons.

GPS goes public

Sometimes disaster can be a catalyst for change, and this was the case in 1983 when the Russians shot down a Korean passenger aeroplane after it accidentally wandered into Soviet airspace.

Ronald Reagan was the president at the time and he decided to allow civilian commercial aircraft to use the GPS system for free, to prevent something like this happening again. The government started working with private companies to develop portable GPS receivers for civilian use. By 1989, the first hand-held navigation device hit the market: the Magellan NAV 1000.

GPS becomes less accurate…for 10 years

As more people were able to get their hands on GPS technology, the government got a little bit worried about terrorist attacks. In 1990 they decided to sabotage their own system, making GPS far less accurate for civilian users. This was called Selective Availability.

This lasted for a decade, until the year 2000: when the Defense Department decided to end it. In the blink of an eye, GPS suddenly became ten times more accurate and became a valuable tool for a number of industries. This was also the year that Al Gore's plan to add two additional signals (specifically for civilians) was approved.

Pocket sized devices become more common

As the new millennium dawned, pocket sized GPS devices started hitting the consumer market. In 1999, the first mobile phone with the technology hit the European marketplace: The Benefon Esc! This was followed a couple of years later with small, in-car satellite navigation systems from companies like Tom Tom.

By the mid-noughties most mobile phones had GPS signal, and by using this in combination with the cellular transmissions, it became possible to pinpoint the user's precise location. It wasn't long before burgeoning social media websites started to take advantage of this, with location based networking websites like FourSquare and downloadable sat-nav apps gaining popularity.

What now?

As of 2013, there are 32 operational GPS satellites floating around up there. There are also three spares, which are currently decommissioned but can step in if any of the others fail. At least 24 satellites are available 95% of the time: pretty good compared to the six satellites pioneered by TRANSIT.

The next generation of satellites are set to launch in 2014, adding an extra civilian signal and generally improving current performance: making it easier than ever to share your location with your buddies on Facebook.

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Editor's Note: Catherine is a keen blogger with a huge passion for writing. Catherine works with various organizations producing unique, informative content around technology and lifestyle.