Satellite navigation is responsible for keeping the modern world working. Many of us do not even know about all – many! – options for its application. At the same time, this system is very vulnerable – and the more vulnerable, the more advanced it is. What happens – what can replace it?
When Ben Gurion Airport in Tel Aviv suddenly began to experience GPS malfunctions last summer, only the skill of air traffic controllers helped prevent serious accidents. The interference that created difficulties for flights for three weeks, according to the Israel Defense Forces, arose due to the work of electronic warfare equipment used by Russia in Syria.
In relation to the Israeli international airport, this, of course, happened unintentionally, but it shows how dangerous such failures in the global positioning system, known to all as GPS, can be.
“We are increasingly realizing that GPS needs to be protected, strengthened and enhanced,” says Todd Humphreys, a satellite communications systems engineer at the University of Texas at Austin, USA.
Many of our daily tasks now depend on GPS.
In its simplest form, the system tells us exactly where on the planet the GPS receiver is located – at any time of the day or night. These receivers are found in our mobile phones and cars. They allow ships to navigate through reefs and difficult canals, acting as a kind of modern lighthouse.
Emergency services rely on GPS (and similar national systems – like Russia’s GLONASS, Europe’s Galileo, or China’s Beidou) to find those in trouble.
And here’s an application that not everyone knows about: ports would not be able to work without satellite navigation, because their cranes need GPS to find the right container.
Satellite navigation systems play a critical role in logistics operations, helping to deliver goods and services accurately and on time. Without these systems, store shelves would quickly empty and prices would be higher.
The construction industry uses GPS to survey construction sites, and fishermen use GPS to comply with strict rules governing fishing.
As you can see, without satellite navigation, our life would simply stop. But is there something that can replace the same GPS? Could we handle it without her?
According to the London School of Economics, commissioned by the British government, just five days without satellite navigation will cost the country more than £ 5.1 billion ($ 6.5 billion).
Due to the failure of the GPS system, the American economy will lose an estimated one billion dollars a day, and if this happens in April and May, when farmers are sowing, then up to one and a half billion a day.
Still, GPS glitches are surprisingly frequent. The military is often the culprit in some parts of the world when testing new equipment or conducting exercises. The US government also regularly conducts tests and exercises leading to the loss of satellite signals. Some technical problems also affect the operation of satellite systems.
Of course, besides GPS, there are other similar systems that we mentioned above – they all work on the same basis as GPS. At the same time, with the development of technology, the likelihood increases that someone will interfere with the operation of these systems and deliberately create interference, or even turn it off.
The military is particularly concerned about this, says Professor Charlie Curry, a researcher at the Royal Institute of Navigation and founder of the British company Chronos Technology, which, among other things, deals with synchronization problems in satellite navigation systems.
The military has a lot to worry about. Satellite navigation was originally developed by the Pentagon and is now used in everything from warships to reconnaissance drones, from smart bombs to infantry. And this system is in danger.
GPS jammers are easy to buy online. Criminals can use them to disable tracking systems for stolen vehicles without caring about who else might be harmed.
But there are more serious dangers.
“There is a distant threat that the entire GPS satellite network could be disabled – as a prelude to war, as an attack on a critical infrastructure element, on the US economy,” says Humphreys.
But the forces of nature can be just as dangerous. The so-called “Carrington event”, the most powerful geomagnetic storm in the history of observation in 1859, could disable the entire current GPS satellite network.
So, if GPS and its satellite sisters suddenly fail – what alternatives do we have? What will help our world to earn again?
One possible backup system is a new version of the LORAN (Long Range Navigation) ground-based radio navigation system, which was developed during World War II to aid the navigation of Allied ships crossing the Atlantic. Instead of satellites, ground-based transmitters with antennas on masts of 200 meters in height were used, transmitting radio navigation signals.
At first, LORAN was accurate to within a few miles, but by the 1970s it was able to provide locations with an accuracy of several hundred meters.
In the 2000s, when GPS made LORAN unnecessary, its transmitters were disassembled in Britain and other countries, but the modern version, known as eLoran, may be as accurate as GPS. It uses advanced transmitters and receivers as well as so-called differential equalization.
This version is said to be capable of locating to an accuracy of 10 meters or more. Unlike GPS, its signals are able to penetrate the walls of buildings and tunnels – primarily because this system uses a lower frequency and higher power than satellite signals.
ELoran’s signals are much more difficult to interfere with and does not rely on vulnerable satellites. The only problem is that someone has to fund its deployment. “eLoran is a great technology that will fill all the navigation gaps,” says Humphreys. “If there are serious intentions to deploy and keep it operational.”
There are other approaches that do not require additional infrastructure. Long before radio was invented, navigators found their way in the ocean through the sun and stars, using a sextant to determine the height of the sun and other objects in space above the horizon to find out their geographic coordinates.
Navigation by the stars is still alive today. Surprisingly, ballistic missiles like the American Trident still use this kind of navigation in flight.
The stars will help establish your place on the planet with an accuracy of one hundred meters. But the American company Draper Laboratory has developed a new-generation stellar navigation system called Skymark, which uses a small automatic telescope to track (in addition to stars) satellites, the ISS and other objects orbiting the Earth.
And since there are an incredible number of such fast moving objects now, Skymark can achieve much higher accuracy than is possible with “slow” stars.
Skymark uses a database of visible Earth satellites – both workers and space debris. The creators claim that the accuracy of the system is 15 meters, which is close to the results of GPS.
Sometimes the accuracy can be even higher, but it depends on how many satellites are visible at the same time and how large they are, emphasizes Benjamin Lane of Draper.
One of the drawbacks of Skymark is that it works in clear skies. Of course, the use of infrared rays, which more easily pass through clouds and fog, helps, but not too much. In some regions of the northern and southern hemispheres, where thick clouds are quite common, the system is not as useful.
Perhaps closer to the beginning of effective use is inertial navigation, which uses accelerometers and gyroscopic devices to determine the exact speed and direction of movement and calculate the position.
Some basic versions of this system are already in use. “When your car is hiding in a tunnel and you lose the GPS signal, it’s inertial navigation that keeps you going,” says Curry.
The problem with this navigation is that it has a “skid” – the calculated position becomes less and less accurate as errors accumulate, so the inertial navigator in your car is useful only for short GPS signal losses.
Quantum sensors, which are thousands of times more sensitive than existing devices, will help overcome the skid problem.
French company iXBlue is using them to create a device that rivals GPS in accuracy, and scientists from Imperial College London, in collaboration with laser specialists at M Squared, showed a prototype of a portable quantum accelerometer in 2018.
Such quantum sensors currently only exist in laboratories, and it will take years before they turn into a finished product.
But the optical navigation system, which uses video cameras to use landmarks on the ground (for example, buildings or road junctions), may well be put into operation soon. The first version, Digital Scene Matching (correlation of the radar display of the terrain with the reference mapping program), was developed for guided (cruise) missiles.
ImageNav, created by Scientific Systems for the US Air Force, is a state-of-the-art optical navigation system for aircraft. To determine the position, it refers to the terrain database and compares it with the information received from the video cameras. ImageNav has been successfully tested on various aircraft, but it may well be suitable, for example, for unmanned vehicles.
Swedish company Everdrone recently carried out the first non-GPS drone delivery. Their system uses a combination of optical navigation (measuring speed by how quickly the landscape on the ground changes) and object identification on the ground, plotting a route from point to point with GPS accuracy.
Of course, this method relies on a complete and accurate base of terrain images, which requires a lot of device memory and frequent updates.
The UK is developing the National Time Center program – the world’s first national service that is designed to back up the GPS system for time synchronization.
When it goes live in 2025, it will use a variety of high-precision atomic clocks located in secure locations across Britain, providing accurate time signals over cable and radio.
The idea is that if the satellite signal is interrupted, then the backup system will not have any single and therefore vulnerable center that can be disabled either accidentally, or due to a technical problem, or through a cyberattack.
By and large, no single system can replace such a powerful navigation system like GPS, and we will most likely use different alternative solutions for different cases – for ships, planes, cars …
The US Department of Transportation has now announced a competition for the best GPS fallback. But the whole question is whether such an alternative can start working quickly enough.
“We know there is a problem, but [to solve it] we are moving at a snail’s pace,” says Curry.
We are becoming more and more dependent on accurate navigation. Self-driving cars, drone-assisted delivery, flying taxis are expected to become a familiar part of the terrestrial and celestial landscape in the coming decade. They will all rely on GPS.
As Curry points out, one person with a powerful satellite signal jammer could disable a GPS system in an area the size of London if applied from the right place.
Until adequate backup systems are developed, it will be possible to stop life in the whole metropolis literally at the click of a button.