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The electronic warfare threat to phone networks: GPS jamming

Technology / news
The electronic warfare threat to phone networks: GPS jamming
HackRF One
HackRF One. Source: Great Scott Gadgets

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.

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 (BLISShave 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.

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14 Comments

Why are cell towers relying on GPS signals?    They have optical backhaul and could easily sync to a ntp server some where on the providers network.  Not like the cell tower is much use if its lost its connection back to the network.

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s/ntp/ptp

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It's time right? The GPS signal isn't just location but also a very very accurate measure of time. I'm guessing if you need to keep the cell towers in sync a highly accurate broadcast of the time at a particular location is an easy way to do it. Seiko make a watch that gets it's time via the GPS network.

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Pragmatist was saying the cell towers are connected to the telco's network via fibre, which would provide a faster connection to an NTP (network time protocol) server than a satellite connection would.
 

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Outside  of major conurbations I doubt the availability of Fibre ot cell towers.

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It's just a cost issue. GPS is the easiest and cheapest way. i.e. listen for 3+ satellite pings and discard the 'bad' one(s).

Were GPS to become unreliable, then other existing techniques can be used to ensure times are accurate enough for ICT networks and core towers will have these enabled. Note that 5G extends these options.

Bit like guided missiles. Most guidance systems don't use just one guidance technology but multiple. Exactly which ones are used, and how many are used, and which take precedence over the others, is kept secret but pretty much every guidance system employed by the majority of advanced countries would continue to function if GPS was blocked or degraded (or 'fake' GPS signals were detected).

The key point of the article is just how ubiquitous GPS has become and how we underestimate the impacts should we lose it. In industries where lives and property are at stake, e.g. shipping, secondary navigation techniques are always employed just in case GPS has gone screwy (or the operators have shut it down for public use and are only sending encrypted pings).

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Yes, that is so. Rideshare and food deliveries in parts of Israel are apparently hopeless. In one part of the country there's a hill or mountaintop where the GPS signal isn't jammed, so drivers head up there to sort out the navigation...

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GPS is owned by the USA government and can be shut off at any time  - and if they needed to they would.  Worldwide.

There will be a procedure in place and you can sure they even rehearse it.

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I think there's at least 3 (maybe more) independant GPS satellite networks. One of which is owned by China, most likely existing for the very reason you mentioned above.

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Europe and Russia have their own too.  Galileo and Glonass

https://en.wikipedia.org/wiki/Satellite_navigation#Classification

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So the question is - will my phone shift to another system?  Or is it fixed to the USA GPS.  If my phone is capable of using other systems, and if so how do I do it.  

What about all the miriad other bits who use GPS.  Are they adaptable, or are we stuck.

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If you look up your phone's specifications, it should tell you which GNSS apart from GPS that is supported. 

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They wouldn't shut it off per se.

They would change the broadcasts to be encrypted and without the decryption key(s) the signals would be useless. (Not sure if that's still how they'd do it though. There are other techniques that can be used.)

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