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Czech Passive Radar Detecting B-2 at 150 miles (2015)

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Re: Czech Passive Radar Detecting B-2 at 150 miles (2015)

#51

Post by jdironman »

JDulin wrote: post #47
ChuckMcM wrote: post #26

Hmm, not your typical RADAR. This is basically using the RF emissions of the plane, and their detection at multiple RF detection stations with synchronized clocks, to determine the difference in arrival time. The radio emissions all travel at the same speed through the air, the difference in arrival time can be used with some simple trig to figure out where the RF emitter is. There are a number of Time Difference of…

More to the point, detecting a stealth aircraft is very different from shooting at a stealth aircraft. This radar would likely not have the location accuracy of where exactly the B-2 was to accurately engage it with a missile. Your accuracy would be limited by the rate of RF pings the B-2 is putting off, and then the margin-of-error of these RF waves and receiver. This is one difference between the B-2 and stealth fi…

And also, searching the top speed of a B-2 at 628mph, if detected at 150 miles out only gives them 14 minutes. Which is both a lot, or a little. Depending on how prepared for action someone is.

Re: Czech Passive Radar Detecting B-2 at 150 miles (2015)

#52

Post by enigmabridge »

You don't necessarily need the aircraft to emit any signals, you may be able to detect changes in the background RF emissions reflected or distorted by the aircraft. It would have to be enormously CPU expensive but if you can correlate changes in tens or hundreds of frequencies, I can imagine it could be done.

Re: Czech Passive Radar Detecting B-2 at 150 miles (2015)

#53

Post by thedance »

What's the mission and purpose of the B-2 these days? It's a penetrating strategic bomber. The justification for it was that it could strike mobile Soviet ICBM launchers. It was never going to be any good for that. What's it for now? Has it ever been used against a sophisticated enemy (i.e. not people who are literally living in caves)?

Re: Czech Passive Radar Detecting B-2 at 150 miles (2015)

#54

Post by greglindahl »

ChuckMcM wrote: post #26

Hmm, not your typical RADAR. This is basically using the RF emissions of the plane, and their detection at multiple RF detection stations with synchronized clocks, to determine the difference in arrival time. The radio emissions all travel at the same speed through the air, the difference in arrival time can be used with some simple trig to figure out where the RF emitter is. There are a number of Time Difference of…

> That said, they are "easy" to jam in the sense that when you have two radio signals on the same frequency,

Not at all. Check out the VLBI technique from radio astronomy, it's not hard to tell that there are two discrete signals.

But that's not really the point: you can see stealth aircraft already with lower frequency radars, just not well enough to shoot them down. It's hard to imagine this passive technique being good enough to shoot them down, either.

https://en.wikipedia.org/wiki/Stealth_technology#Low-frequen...

Re: Czech Passive Radar Detecting B-2 at 150 miles (2015)

#55

Post by m4rtink »

nradov wrote: post #42

Many people fail to understand that there's a huge difference between detecting the presence of an aircraft and actually targeting it. Anti-aircraft weapons must be precisely targeted to have any chance of hitting. So a passive radar can be useful in limited circumstances for cueing other sensors but it can't accomplish much by itself.

Could the adversary still just send cannon equipped fighters to the general that would locate the stealth bomber visually and shoot it to pieces ?

Sure, could be rather hard to do in the night but once a stealth bomber is sighted visually, it is toast - B2 simply has no self defence weapons available at all.

A stealth fighter could be better off if it can defend itself while still avoiding others getting a weapon lock, effectively forcing them to use visually sighted cannon while it can use sensor guided gun and missiles normally.

Re: Czech Passive Radar Detecting B-2 at 150 miles (2015)

#56

Post by coretx »

fest wrote: post #41
catalogia wrote: post #36

Earlier quoted context omitted.

> multiple RF detection stations with synchronized clocks, to determine the difference in arrival time. The radio emissions all travel at the same speed through the air, the difference in arrival time can be used with some simple trig to figure out where the RF emitter is. That's a fancy way to say 'triangulation'.

I believe it's technically trilateration, not triangulation.

Contemporary passive radar arrays are phase sensitive so it ain't that simple either.

Re: Czech Passive Radar Detecting B-2 at 150 miles (2015)

#57

Post by imtringued »

nradov wrote: post #42

Many people fail to understand that there's a huge difference between detecting the presence of an aircraft and actually targeting it. Anti-aircraft weapons must be precisely targeted to have any chance of hitting. So a passive radar can be useful in limited circumstances for cueing other sensors but it can't accomplish much by itself.

Stealth bombers aren't going to dodge missiles. They need to reach their target before they are noticed at all. Otherwise the enemy will mount a response and intercept the bomber.

Re: Czech Passive Radar Detecting B-2 at 150 miles (2015)

#58

Post by sfifs »

JDulin wrote: post #47
ChuckMcM wrote: post #26

Hmm, not your typical RADAR. This is basically using the RF emissions of the plane, and their detection at multiple RF detection stations with synchronized clocks, to determine the difference in arrival time. The radio emissions all travel at the same speed through the air, the difference in arrival time can be used with some simple trig to figure out where the RF emitter is. There are a number of Time Difference of…

More to the point, detecting a stealth aircraft is very different from shooting at a stealth aircraft. This radar would likely not have the location accuracy of where exactly the B-2 was to accurately engage it with a missile. Your accuracy would be limited by the rate of RF pings the B-2 is putting off, and then the margin-of-error of these RF waves and receiver. This is one difference between the B-2 and stealth fi…

If you can localize down to the range of a km? Can't you just shoot down optically? A giant dark plane blotting out the stars...

Re: Czech Passive Radar Detecting B-2 at 150 miles (2015)

#59

Post by ISL »

jdironman wrote: post #51
JDulin wrote: post #47

Earlier quoted context omitted.

More to the point, detecting a stealth aircraft is very different from shooting at a stealth aircraft. This radar would likely not have the location accuracy of where exactly the B-2 was to accurately engage it with a missile. Your accuracy would be limited by the rate of RF pings the B-2 is putting off, and then the margin-of-error of these RF waves and receiver. This is one difference between the B-2 and stealth fi…

And also, searching the top speed of a B-2 at 628mph, if detected at 150 miles out only gives them 14 minutes. Which is both a lot, or a little. Depending on how prepared for action someone is.

Or a lot less than that, if the B-2 isn't using gravity munitions.

Re: Czech Passive Radar Detecting B-2 at 150 miles (2015)

#60

Post by ta999999171 »

nradov wrote: post #38
chmod775 wrote: post #27

Earlier quoted context omitted.

> Drop them on a military base If you can get close enough to drop a bunch of slow drones, you can get close enough to just drop a bomb on the whole thing instead. Much more bang for your buck. Let's also not forget that small drones might become 'banned' much like chemical weapons did, if they ever became viable.

Small drones will never be banned by international treaty. There is zero chance of that.

Why?
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