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Comment by kortilla | Hacker News Reader

They suffer a minor inconvenience as precision is lost. The US military frequently does selective jamming near bases and other ‘special’ areas.

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The tricky bit here is that this is a civilian airport. Jamming GPS could reasonably be expected to cause significant difficulties for civilian planes and pilots. And thus passengers.

The airport was already disrupted because of the drones, disrupted to the point of shut down. thus the article.

As has been mentioned earlier, there are 5 airports in London.

There aren't five airports in London. There are quite a few airports with "London" in the name, but they aren't particularly close to London. London Luton Airport, for instance, is ~45km north of London, and London Gatwick is ~50km south of London. There's ~100km distance between Luton and the airport that was affected by the drones.

How do you think those planes get to those airports? There are planes flying all over the south east going to if from numerous airports. Then there’s the impact on GPS in cars, trucks, phones, police vehicles, ambulances, all sorts of emergency services. We’d have to be extremely careful about potential impact before considering such a drastic step that has a very small chance of actually being effective.

I think you might have misread my comment. What I said was that there aren't five airports in London. You seem to have understood that to mean something very different.

All flights were grounded anyway

Not really, whatever you are jamming you can just make sure it doesn't make it 10 km up in the air where most of the planes are (especially given the GPS patch antenna pointing up from the plane), and I don't believe they need GPS signal on takeoff/landing, they use older tech for that.

10km up? What about all the planes landing at the other airports of London?

Most of which are geographically distant enough to not be affected by localised jamming.

Never mind that Aircraft will be under ATC in UK airspace, and ATC uses Radar + transponder to localise aircraft.

GPS is a navigational aid, not the primary navigation tool.

> (...) I don't believe they need GPS signal on takeoff/landing, they use older tech for that.

Much older. The basic "stack" uses radio beacons, not greatly different from early XX century tech. The more advanced Instrument Landing System is quite a bit more complex, but in very basic terms is a set of radio beacons that define a glide path. It is local, and requires no GPS.

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