GPS Spoofing

[Chiefy]

http://www.theregister.co.uk/2013/07/29/texas_students_hijack_superyacht_with_gpsspoofing_luggage/

[HarmlessWeasel]

I wonder if the crew were warned and if not, how long it took them to figure it out (assuming they did)

[CharlieDelta]

This sort of thing should be easy to pick up by comparing your DR position to what the GPS is giving you, unless they've found a way to interfere with the gyro and log as well. If you're using ECDIS, your ground course and speed information would become suspect. This would prompt you to get the sextant out and see what's what.

[bobofinga]

Any half decent OOW should notice this pretty quickly... especially if Near Coastal.

[HarmlessWeasel]

Isn't COG calculated from the GPS signal?

Yeah the video said they started it 30 miles from shore so no landmarks

[CharlieDelta]

Isn't COG calculated from the GPS signal?

COG/SOG are calculated from position fix to position fix. GPS will give instantaneous COG/SOG by virtue of its continuous fixing. If someone interferes with your GPS, your COG/SOG will change to match the new series of position fixes.

When they diverge from your gyro heading/log speed by a significant amount then you can pick things up. There's usually some variance due to the effects of leeway/tide/currents, but alarm bells should start ringing if you're not expecting it to change/the change doesn't tally with the conditions.

[HarmlessWeasel]

COG/SOG are calculated from position fix to position fix. GPS will give instantaneous COG/SOG by virtue of its continuous fixing.

sorry badly worded question. I understand that's how it's calculated, but if the GPS is being spoofed then won't the readout for COG match whatever the spoofing is doing and so the COG will look relatively normal?

[chris]

eLoran to the rescue then

[CharlieDelta]

sorry badly worded question. I understand that's how it's calculated, but if the GPS is being spoofed then won't the readout for COG match whatever the spoofing is doing and so the COG will look relatively normal?

Oops sorry, got that after posting, have edited my post.

[HarmlessWeasel]

Ah ok, gotcha. Thanks

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[GuinnessMan]

Sounds like the way they lured the ship in that James Bond film...

[HarmlessWeasel]

Sounds like the way they lured the ship in that James Bond film...

I'll be in my secret evil oil tanker lair...

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[Clanky]

In the case of the White Rose of Drachs hijacking, there's also little need for concern. The ship carries a crew of 18 and no captain relies solely on GPS. Any significant course deviation would most likely be noticed by those on watch during regular position checks.

Yeah, right!

[YoungMariner]

Well hold on, on all electronic navigation systems I've sailed on where the autopilot can navigate the trackline/COG there is an alarm when the Gyro and COG deviate by the pre-set limits....
If the vessel was sailing on a gyro heading, then of course any false GPS input wouldn't directly affect the course of the vessel.

[CharlieDelta]

Exactly. It really would be a long shot to see the likes of big cruise ships being fooled into running aground/colliding. You would need an extraordinarily long "error chain" that, on top of the spoofing, included gross negligence, system failures and so on. They seem to discount the functionality of the systems we already have and the knowledge of the ship's officers. And while having continuous, instantaneous position information available is great, it's not really necessary.