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France's aircraft carrier located in real time by Le Monde through fitness app

lemonde.fr

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Re: France's aircraft carrier located in real time by Le Monde through fitness app

#201

Post by kjkjadksj »

cwillu wrote: post #166
vntok wrote: post #136

Earlier quoted context omitted.

Track not the ship itself but the planes that take off and land on it. Many sites will expose their paths, you'll see the planes circling in a pattern around "some void" - that's the ship.

If de Gaulle is turning off AIS, it stands to reason that it's also turning off the transponders in the air wing.

Maybe, maybe not. When the US did their venezuela maduro operation they turned on adsb on f15e for whatever reason. And only turned it on for like a portion of the mission so maybe that wasn’t intentional.

Re: France's aircraft carrier located in real time by Le Monde through fitness app

#202

Post by Sanzig »

throwaway894345 wrote: post #177
Sanzig wrote: post #134

Earlier quoted context omitted.

Eh, not really. Synthetic Aperture Radar satellites used for marine ship detection have extremely wide sensor swath widths, and ships show up as very bright radar targets against the ocean. Detecting a large ship, even in a very large search area, is almost trivial. Identifying a ship is harder, but not insurmountable. In particular, large ships like aircraft carriers tend to have very identifiable radar signatures i…

How do these work? I would think radar would have a very difficult time seeing a ship against the backdrop of the ocean from so high above. Is the satellite bouncing radar waves off the side of the ship as the satellite is near the horizon? Even if you can detect a ship, I'm having a hard time imagining a sufficiently high radar resolution for such a wide sensor swath width at such an extreme range. Is the idea that…

SAR operates in side-looking slant geometry.

Consider shooting a ray at the ocean at an oblique angle from a satellite: it bounces off and scatters away from you. Hardly any of the energy scatters back towards you.

Now, put a ship there. The ray bounces off the surface of the ocean and scatters up into the side of the ship, and from geometry, it's going to bounce off the ship and come straight back towards its original source. You get tons of energy coming back at you.

A ship on the ocean is basically a dihedral corner reflector, which is a very good target for a radar.

> I'm having a hard time imagining a sufficiently high radar resolution for such a wide sensor swath width at such an extreme range. Is the idea that you locate it with the wide sensor swath and then get a detailed radar signature from a more precise sensor?

That's one approach, there are so-called "tip and cue" concepts that do exactly this: a lead satellite will operate in a wide swath mode to detect targets, and then feed them back to a chase satellite which is operating in a high resolution spotlight mode to collect detailed radar images of the target for classification and identification.

However, aircraft carriers are big, so I don't think you'd even need to do the followup spotlight mode for identification. As an example, RADARSAT-2 does 35 meter resolution at a 450 km swath for its ship detection mode. That's plenty to be able to detect and identify an aircraft carrier, and that's a 20 year old civilian mission with public documentation, not a cutting edge military surveillance system. There are concepts for multi-aperture systems that can hit resolutions of less than ten meters at 500 km swath width using digital beamforming, like Germany's HRWS concept.

tl;dr: Radar works very well for this.

Re: France's aircraft carrier located in real time by Le Monde through fitness app

#203

Post by mytailorisrich »

deepsun wrote: post #89
elif wrote: post #77

I seriously doubt there is a country on earth which lacks the capability to detect an aircraft carrier's presence in the Mediterranean sea. We are not talking about stealth vehicles.

Mediterranean maybe (although I'm not sure), but it's actually very hard to find a ship, even as large as an aircraft carrier, in the ocean. The empty space is just too big. Satellites have hard time taking pictures of every square mile of a sea to find any ship, yet alone the one you need.

Satellites only have to track, not find.

Aircraft carriers sail from home ports and are frequently visible to all. The Charles de Gaulle was previously in Denmark for instance, then obviously everyone can also see you crossing the English Channel and Straight of Gibraltar.

So from there it is only a matter of keeping an eye on it for anyone with satellites. So obviously all the "big guys" know where the other guys' capital ships are.

Re: France's aircraft carrier located in real time by Le Monde through fitness app

#204

Post by CGMthrowaway »

elif wrote: post #88

An aircraft carrier can be seen with the naked eye from 10 meters above the shore for about 28 miles. So the entire Spanish coast, Moroccan coast, Algerian coast, mallorca, sardegna, Sicily, tunesia, the Greek isles, and who knows how many cruise ships, fishing vessels, and commercial aircraft all saw this ship.

Are you aware of a policy that allows Strava when within sight of shore, but bans it when under more sensitive operation?

Or is this article perhaps better interpreted as an example of a dangerous behavior that could be happening also during those sensitive times (in which case, it is unlikely that French media would be even running a story with a map of the sensitive location)?

Re: France's aircraft carrier located in real time by Le Monde through fitness app

#205

Post by PeterStuer »

philipwhiuk wrote: post #191
PeterStuer wrote: post #185

Many questions: I can assume Strava is GDPR compliant and would not publish this information without the sailors concent? Does the French military not stress in their training the dangers of these data disclosures? Why does the carriers network not have adequate measures against this sort of data exfiltration? Why is Le Monde tracking a french sailors location data?

> I can assume Strava is GDPR compliant and would not publish this information without the sailors concent? Historically there was a problem where user's data was aggregated into a global view. But these days you'd have to follow the user on Strava to get this sort of track. I suspect that a journalist at Le Monde has a naval buddy on Strava and posted the story.

So how did the carriers network not block Strava? I doubt the sailors watch was direct to satellite.

And why would a Le Monde 'journalist' dox his 'buddy' and expose and thus endanger the ship? Anything for a click?

Re: France's aircraft carrier located in real time by Le Monde through fitness app

#206

Post by torginus »

jcalx wrote: post #85
paxys wrote: post #2

Is an aircraft carrier's location supposed to be secret? Pretty hard to hide from a satellite I'd imagine.

I would have thought so too but Naval Gazing has a short series [0] on why it's not as dire as one might think. An aircraft carrier's location being "secret" in this case is just one layer of the survivability onion [1] anyhow. (Caveat that as someone who takes a casual interest in this, I can't vouch for accurate this is at all.) [0] https://www.navalgazing.net/Carrier-Doom-Part-1 [1] https://www.goonhammer.com/star…

Well everything's impossible, until its not.

Re: France's aircraft carrier located in real time by Le Monde through fitness app

#207

Post by thisisnotmyname »

elif wrote: post #77

I seriously doubt there is a country on earth which lacks the capability to detect an aircraft carrier's presence in the Mediterranean sea. We are not talking about stealth vehicles.

Isn’t the point that if you can identify one naval vessel by this means you can probably identify many?

Re: France's aircraft carrier located in real time by Le Monde through fitness app

#208

Post by garyfirestorm »

elif wrote: post #77

I seriously doubt there is a country on earth which lacks the capability to detect an aircraft carrier's presence in the Mediterranean sea. We are not talking about stealth vehicles.

We couldn’t find a commercial jet (MH370). Both, while it was still flying in the air and after it was presumably lost in the ocean. They couldn’t track it in the air nor can they still find its remains after looking for it for so long. This problem is not trivial.

Re: France's aircraft carrier located in real time by Le Monde through fitness app

#209

Post by bigyabai »

maxerickson wrote: post #178
fxtentacle wrote: post #131

Earlier quoted context omitted.

You can rent access to nearly real-time custom satellite targeting for <$3k per image. That means while you're correct that not all countries can afford it, most can.

So you task the satellite to where you know the ship is?

To get a naval fix, you usually define an "area of uncertainty" around the last confirmed location of the ship. The area is usually a circle with the radius being the maximum distance the ship/group could travel at full speed.

So, you don't exactly "know" where the ship is, but you can draw a hypothetical geofence around where it's likely to be, and scan that area.

Re: France's aircraft carrier located in real time by Le Monde through fitness app

#210

Post by OneDeuxTriSeiGo »

throwaway894345 wrote: post #177
Sanzig wrote: post #134

Earlier quoted context omitted.

Eh, not really. Synthetic Aperture Radar satellites used for marine ship detection have extremely wide sensor swath widths, and ships show up as very bright radar targets against the ocean. Detecting a large ship, even in a very large search area, is almost trivial. Identifying a ship is harder, but not insurmountable. In particular, large ships like aircraft carriers tend to have very identifiable radar signatures i…

How do these work? I would think radar would have a very difficult time seeing a ship against the backdrop of the ocean from so high above. Is the satellite bouncing radar waves off the side of the ship as the satellite is near the horizon? Even if you can detect a ship, I'm having a hard time imagining a sufficiently high radar resolution for such a wide sensor swath width at such an extreme range. Is the idea that…

Even with an extremely low resolution radar hit they are very identifiable.

Most naval vessels move in groups/squadrons. Carriers basically always travel with a "carrier strike group"/CSG of a dozen other ships and destroyers often travel in "destroyer squadrons"/DESRONs. So any time you see a cluster of hits, just by the relative responses of each hit you can narrow down and guess the entire CSG/DESRON in one go and then work out which responses map to which ship in the CSG/DESRON once you have a good idea of which group you are looking at.

This is especially true because ships even within the same class have varying ages, different block numbers, and differing retrofits. So each one has a unique signature to it.

But also if you aren't completely certain you can always come back with a second high resolution pass and then it's trivial to identify each ship just visually.

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