Can China jam your GPS?
IN MARCH, WHEN President Donald Trump briefly withheld intelligence support from Ukraine, the shock waves buffeted America’s allies, who worried they could no longer take for granted access to the superpower’s vast space-based resources. This uncertainty extends beyond defence to equally crucial tools, such as the Global Positioning System (GPS).
The navigation system has long been an unshakable pillar of American power, hard and soft. First developed by the Department of Defence, President Bill Clinton fully opened GPS to civilian use in 2000, transforming it into a free global utility that is now deeply embedded across industries, from air transport, shipping and trucking to global finance, where its signals provide the accurate timestamps needed to synchronise banks and exchanges. If these navigation signals were to be cut off for 24 hours, the costs to the British economy alone would come to about £1.4bn ($1.9bn), according to a government report published in 2023.
Worryingly, years of under-investment have left GPS vulnerable. The large-scale jamming (blocking the signal) and spoofing (feeding in false information) of GPS in or near war zones, including Ukraine and the Middle East, have exposed its fragility (see chart). Kevin Pollpeter, the head of research at the China Aerospace Studies Institute, a think-tank, warns that such disruptions will grow more common, as Russia and China invest in technologies capable of jamming GPS on a massive scale.
China’s BeiDou has emerged as a formidable alternative to GPS. The Chinese system is provided by 56 satellites, which is nearly double the number providing GPS, and is supported by 120 ground stations, which command the constellation, versus just 11 for GPS. This resilience is BeiDou’s greatest strength, says Dana Goward, the president of the Resilient Navigation and Timing Foundation, a non-profit. Unlike GPS, which relies solely on satellites in medium-Earth orbit, BeiDou operates across three orbital layers, giving it wider and more stable coverage.
Beyond its satellite network, China has also built nearly 300 ground-based backups, fibre-optic networks to transmit accurate timing information, and an eLoran system, a ground-based alternative to satellite-based navigation. These ensure that if satellite signals are lost, essential navigation and timing services can continue. Unlike satellite signals, which are weak and easily jammed by the time they reach Earth, eLoran uses powerful transmissions that are more difficult to interfere with.
This redundancy could give China a strategic edge. In a conflict over Taiwan, for instance, it could jam or spoof GPS signals across the Taiwan Strait, disabling navigation for American and Taiwanese forces, says Mr Pollpeter. Meanwhile, China’s alternative systems would remain largely unaffected because such powerful signals would be needed to jam eLoran that in doing so America might disrupt its own systems, says Sean Gorman, founder of Zephr, a navigation-resilience firm.
Moreover, China’s ability to spoof GPS signals is growing. Because BeiDou is designed to be compatible with GPS, owing to an interoperability agreement signed in 2017, China can easily mimic its signals. Russia and China are also developing anti-satellite and other space-based devices that can destroy or interfere with Western satellites.
America’s communications regulator said on March 27th that it would explore alternatives to GPS to strengthen resilience. However, efforts to modernise America’s ageing GPS satellites have stalled. An upgrade meant to replace 1990s-era technology offered only modest improvements in accuracy, leaving GPS lagging far behind BeiDou and Galileo, a European alternative. In a damning report in 2024 the Government Accountability Office, a congressional watchdog, noted that America has taken more than 20 years to deploy M-code, a jam-resistant military signal that is still not fully operational.
Frustrated by the shortcomings of GPS, some countries are developing their own navigation systems. Britain briefly flirted with the idea of launching a satellite system after Brexit reduced its access to Galileo, but it soon balked at the cost. Instead it is building a cheaper backup using atomic clocks, fibre-optic cables and eLoran transmitters and is testing quantum sensors. South Korea and Japan are continuing to develop their own solutions. Yet since few countries can afford to create global navigation system, most rely on GPS, BeiDou, Galileo or Russia’s GLONASS.
Of these BeiDou is making great strides. It is being embedded in Chinese-built infrastructure, such as phone networks, power grids, ports and railways built under China’s Belt and Road Initiative. Pakistan and Saudi Arabia are using it to replace GPS in some defence applications. Because some devices are locked into using only BeiDou, that creates new vulnerabilities. “BeiDou gives China an on-off switch for countries that rely on it,” says Mr Goward. “That’s a powerful tool for economic and political coercion.” ■