The Global Positioning System we know today, which powers all of our marine navigation systems (including charts, tracking apps and fish finders), was birthed out of the cold war. During the launch of Sputnik 1 (the first ever artificial Earth satellite) by the Soviet Union in October 1957, American scientists quickly discovered they were able to track the vehicle through shifts in its radio signal known as the ‘Doppler Effect’.
In 1958, the Advanced Research Projects Agency (ARPA) used this principle to start work on ‘Transit’, the world’s first global satellite navigation system. The initial satellites were launched in 1960 and quickly became capable of providing accurate navigation to the US military, particularly nuclear missile submarines. The programme then transitioned to the US Navy in the mid-1960s, and by 1968 a constellation of 36 satellites were fully operational.
In 1972 the satellite navigation programme was transferred to the US Airforce which started full development of a robust and stable satellite navigation system named ‘Navigation System with Timing and Ranging’ (NAVSTAR Block-I series). The first experimental satellite in this group was launched in 1978, with 23 other dedicated satellites sent up into orbit to make the system fully operational over the following seven years.
The KAL disaster opens up safety
After Korean Air Lines Flight 007 was shot down when it mistakenly entered Soviet airspace, President Ronald Reagan announced that the GPS system would be made available for civilian use in September 1983 to improve global aviation safety. However civilian operation was limited to an average accuracy of 100 metres by use of ‘Selective Availability’ (a deliberate error introduced into the GPS data which military receivers could correct for).
GPS technology advanced quickly, with scientists commencing new Block-II satellite design in 1985, with the first successful series launch in 1989.
Enter the consumer
In 1989, commercial hand-held GPS units became available to the consumer (including the Magellan Corporation’s NAV 1000), but with a hefty price tag of around $15,000 in today’s money.
Due to miniaturisation improvements developed over the following 10 years, GPS technology appeared for the first time in a cellphone and also began to show up in automobiles in the late 1990s.
Improving consumer accuracy and signal availability
Thankfully for the benefit of boaties everywhere, President Bill Clinton signed a policy directive to turn off Selective Availability in May 2000 to provide the same level of accuracy to civilians as the military enjoyed.
Due to the demand for accurate global positioning, the price of a GPS receiver and processing chip quickly dropped from roughly $6,000 to $3. The ten-fold increase in accuracy coupled with the decrease in cost led to a massive increase in GPS usage for in-car navigation, location-based services, personal technology and marine usage in shipping, sailing and other industries.
GPS today
The 30-plus satellites that make up our current GPS system are orbiting the Earth almost 20,000 kilometres above us and travel at roughly 11,000kph, making two complete orbits in less than 24 hours. This extensive coverage allows the ongoing ability to triangulate our exact position with ease (and free of charge).
While we certainly appreciate GPS while we are cruising or sailing on the water, it’s estimated that since the 1980s, GPS satellites have helped generate nearly $3 trillion in global economic benefits.
The next time you are entering a tricky bay surrounded by submerged rocks, spare a thought for the scientists and engineers who worked hard to give us a truly incredible technology we all use almost every time we go out on the sea.
