It’s been several months since I read Ingrid Burrington’s Atlantic article on Keith Kjoller and Peter Lumsdaine’s attempt to destroy GPS satellites because the system was “military in its origins, military in its goals, military in its development.” My immediate response was that GPS had actually had less to do with military operations – especially targeting – than many other contemporary systems, and that Kjoller and Lumsdaine targeted GPS not because it was a military but because it was civilian enough to be well-known.
I still can’t help wondering, what percentage of the navigation and targeting in the first Gulf War was actually connected to GPS? What other systems were in use then, and were they anywhere near as intertwined between civilian and military uses as GPS was?
I started my search with the TERCOM terrain-following technique used by the non-GPS-guided cruise missiles fired during the war, and quickly discovered that this was a far more complicated topic than I had though. It’s going to take me a while to chew through all the material, but in the meantime it put me on to an interesting story that shows that the fuzzy boundary between military and civilian systems has always been controversial.
In this case the story starts with an interesting article by historian William Rankin, published in Technology and Culture a few years ago. “The Geography of Radionavigation and the Politics of Intangible Artifacts” argues, among other things, that radionavigation was offering a globe-spanning positioning system long before GPS came into service. A profusion of systems, developed by both Axis and Allies during World War II, meant that by the 1960s positioning via radionavigation – though not as as precise or as consistent as via GPS – was available over most inhabited parts of the world.
The Rise of Radionavigation
The most successful long-range radionavigation systems at the end of the war used the same basic principle that would be applied with GPS. By measuring the difference in the arrival time of radio signals from two synchronized stations with known positions, you could locate yourself along a single “line of positioning.” These lines are hyperbolas, which gives such systems the name “hyperbolic navigation.” Taking measurements from two pairs of stations gives two lines, which should overlap in only one or two locations. Taking measurements from three pairs means should lead to a single position.
The US system, called Loran (short for Long Range Navigation), had a reliable range of about 1,500 km and an absolute accuracy of 1,800 meters, but an improved system with better range and accuracy, Loran-C, was in military service by 1957. Using a lower frequency and more precise time delay measurements, Loran-C gave its users a reliable range of about 1,850 kilometers and an absolute accuracy of 460 meters or less, which was pretty impressive for the time.
NATO soon adopted Loran as its standard long-range navigational aid, and the US lost no time in spreading chains of Loran stations across the world to offer precision navigation wherever possible. Unsurprisingly, there was a focus on the seas surrounding Europe and the Soviet Union, since Loran would be both a valuable wartime aid and a way for US ballistic missile submarines – tied at the time to waters close to the USSR because of the 1,900 km range of the first Polaris missiles – to update their inertial navigation systems (INS). (International navigation systems have a tendency to “drift,” so an occasional reset based on an external fix is necessary to keep them accurate.) Unsurprisingly, circa 1962, there was good coverage of the Mediterranean from a chain with stations in Italy, Turkey, Libya, and Spain and of the Norwegian Sea from a chain with stations in mainland Norway, Jan Mayen Island, Iceland, and the Faroes.
That’s where Rankin’s article concludes, with a net of navigational signals – not just Loran-A and -C, but also several competing European systems – that spread across most of the earth. Despite being a military service that wouldn’t be made available to civilian users until 1974, the spread of Loran-C didn’t attract much adverse attention. Not least that was because the US didn’t necessarily tell partner nations about the specific connection between the system and the SLBM fleet. (That was something that would cause trouble in Norway later on.) Loran’s semi-successor, the truly global Omega radionavigation system, did not avoid the limelight.
Forward to Part Two