The electronic warfare threat to phone networks: GPS jamming

Warfare in the 2020s is quite an eye opener, as it really shows how far we've come with using technology to kill each other in new and innovative ways. From first-person view drones taking out armoured columns and troops, to unmanned sea vessels sinking Russian warships, and more, conflicts have become increasingly machine driven with devastating effect on the humans in the battlefield.

Electronic countermeasures are now common, and that includes jamming and interfering with the satellite-based Global Positioning System (GPS) that's used for location finding and navigation worldwide - and other, not so obvious uses that are equally sensitive and important. Read on.

First, note that very large areas can be affected by GPS jamming. If you look at GPSjam.org, the map shows widespread signal interference in Eastern Europe, and the Middle East.

Source: gpsjam.org

A suspected GPS jammer operates from the Russian exclave Kaliningrad/Königsberg since the invasion of Ukraine, disrupting thousands of flights and navigation in general.

The Baltic GPS Jammer is in Kaliningrad.

Fourth proof, refined dataset, second method.

Jammer seems to be stationary or atleast always on land.

Animated over time: radio horizons of the positions where planes first encounter the jammer.

Kaliningrad, Russia outlined. https://t.co/Zt99kkyOIO pic.twitter.com/jP6rfmkG5m

— Markus Jonsson (@auonsson) April 2, 2024

If you think about it, GPS jamming is a pretty cost-effective offensive attack method to cause disruption and inconvenience for the opposition.

However, interfering with GPS can be for defensive purposes as well. Israel is jamming GPS signals currently, supposedly in anticipation of an expected revenge missile attack by Iran, although this is not confirmed officially. 

Because we're so dependent on GPS these days, the threat of jamming should be taken seriously. It affects way more things than is apparent at first.

"We all know how important GPS is today. Our smartphones use location services for maps, for apps, for tracking our food orders, even serving us location specific ads," Telco2 consulting engineer Jonathan Brewer explained to interest.co.nz.

"The 1997 Bond movie Tomorrow Never Dies opens with the bad guys sending a British frigate into Chinese waters using a stolen GPS encoder," Brewer said.

"What took an international criminal gang to accomplish 27 years ago can be done today by any diehard techie with a credit card. Software Defined Radios like HackRF are available everywhere, from reputable international suppliers to small Chinese sellers on AliExpress to homegrown solutions like KiwiSDR. These devices are key to generating noise that can act as a denial of service attack and signals which can trick GPS receivers into receiving and interpreting false data," he said.

The Maritime Administration of the United States Department of Transportation issued a warning on GPS interference for shipping last year, saying "lost or inaccurate GPS signals affecting bridge navigation, GPS-based timing, and communications equipment (including satellite communications equipment)".

Apart from confusing and hampering location finding and navigation, there are some less than obvious consequences from jamming GPS signals, Brewer said.

"What we often don't think about is what else GPS is used for. Almost every cell tower in New Zealand relies on GPS signals to synchronise their transmissions. When that GPS signal is corrupted or goes away, equipment clocks get out of sync. Eventually some 4G and 5G services shut themselves off. Depending on the network, a shutdown could happen within minutes or hours of a GPS disruption."

Having mobile phone cellular service degraded or even taken out by GPS jamming would indeed be suboptimal.

The problem has been known for some time now, and countermeasures such as Blind Interference Signal Suppression (BLISS) have been developed to mitigate it. New Zealand frequency and timing control specialist Rakon has published some suggestions on how to address the GPS vulnerabilities for 4G/5G base stations.

GPS jamming is a reminder of how complex modern warfare is, and the huge amount of less-than-obvious attack surfaces out there.