‘A massive solar storm, one like the Carrington Event of 1859, could bring down the entire GPS satellite network’
Satellite navigation keeps our world running in ways many people barely realise, but it is also increasingly vulnerable. What could we use instead?
When satellite navigation was jammed at Israel’s Ben Gurion airport last year, only the skill of the air traffic controllers prevented serious accidents. The jamming was apparently accidental, originating with Russian forces fighting in Syria, but it highlighted just how dangerous interruptions to the global positioning system – better known as GPS – can be.
“There is a growing recognition of the need to protect, toughen, and augment GPS,” says Todd Humphreys, a communications engineer at the University of Texas, Austin. GPS now underpins a surprising amount of our everyday lives. In its simplest form it tells us where on Earth at any time a GPS receiver is.
We have them in our mobile phones and cars. They enable boats to navigate their way through difficult channels and reefs, like a modern-day lighthouse. Emergency services now rely upon GPS to locate those in distress.
Less obviously, ports would cease to operate, as their cranes need GPS to find the right container to move, and they play a crucial role in logistics operations, allowing car manufacturers and supermarkets to take advantage of just-in-time delivery systems. Without it, our supermarket shelves would be emptier and prices would be higher.
The construction industry uses GPS when surveying and fishermen use it to comply with strict regulations, But GPS is not only about identifying locations, it is also about time.
The constellation of 30 satellites held in orbit around the Earth all use multiple, extremely precise atomic clocks to synchronise their signals. They allow users to determine the time to within 100 billionths of a second. Mobile phone networks all use GPS time to synchronise their base stations, while financial and banking institutions rely upon it to ensure trades and transfers occur correctly
We really would be lost without satellite navigation. But is there anything out there that could replace it? And how might we cope without this ubiquitous system?
A loss of satellite navigation for five days would cost the UK alone more than £5.1bn ($6.5bn) , according to an assessment by the London School of Economics for the British Government. A failure of the GPS system would also cost the US economy an estimated $1bn (£760m) a day, and up to $1.5bn (£1.1bn) a day if it occurred during planting season for farmers in April and May.
But GPS outages are surprisingly common – the military regularly jams it in certain areas while testing equipment or during military exercises. The US Government also regularly performs tests and exercises that lead to disruption of the satellite signal, but also some technical problems lead to worldwide issues.
There are, of course, other global navigation satellite systems available – the Russian Glonass, Europe’s Galileo and China’s BeiDou all work on a similar basis to GPS. But increasingly, interference or deliberate jamming can also lead to interruptions in the signals from satellite positioning systems.