[Answered] Air defense problems

[edsw]

Hello everyone, I have a question about air defense systems. In a recent update, the so-called "Doppler shift" was introduced, a rulelessly correct and necessary innovation, but it seems to me that it touched some air defense systems as well, making them essentially useless, enemy planes just start flying at 90 degrees and missiles air defense lose their goal. Below I provided a screenshot for a better understanding of the problem, here the S-300 shoots at the F-16 and simply spends rockets in the empty.

P.S. I ask for my English, I write through a translator.

[Dimitris]

Hi,

I see what you mean, but what would you consider a "solution" ?

Is doppler notching a valid real-life tactic or not ?

What are we modelling wrong ?

[edsw]

ORIGINAL: Dimitris

Hi,

I see what you mean, but what would you consider a "solution" ?

Is doppler notching a valid real-life tactic or not ?

What are we modelling wrong ?

I’m not a great specialist, but I’m not sure that the air defense systems radar work according to the Doppler principle (it is initially needed so that the aircraft radars see targets against the background of the earth), but in any case it seems to me that it’s too easy to evade air defense systems , no jamming systems or dipole reflectors are needed, just keep a 90 degree angle and not a single air defense system will reach you). I don't know if this is right or wrong, but it seems a little implausible.

[VIF2NE]

Obviously, the S-300 radar will have a radial target speed N1. The direction finder of the guided missile has a radial target speed N2. Therefore, modern SAMs are so tough.

And of course there are other ways to track the target at a small radial speed.
This flaw was fixed a very long time ago. Soviet SAM successfully fired on balloons.

[Sardaukar]

I agree that 90deg beaming should be adjusted a bit, based maybe on generation of the missile.

[Dimitris]

There are already a number of factors at play, it's not nearly as simple as "turn perpendicular and you go poof".

At the technical level, what notching does is to merely reduce the apparent RCS of the detection target - sometimes substantially so, other times less so, depending on a few things. Thus, as a tactic, it is vulnerable to all the remedies against low RCS: Decrease distance, increase power, detect from multiple sides etc. It is also very sensitive to crew skill (an ace pilot will have a much stronger effect than a novice).

[Sardaukar]

So far, I am fine with this. Need to play more to get more grievances [:D]

[edsw]

ORIGINAL: Dimitris

There are already a number of factors at play, it's not nearly as simple as "turn perpendicular and you go poof".

At the technical level, what notching does is to merely reduce the apparent RCS of the detection target - sometimes substantially so, other times less so, depending on a few things. Thus, as a tactic, it is vulnerable to all the remedies against low RCS: Decrease distance, increase power, detect from multiple sides etc. It is also very sensitive to crew skill (an ace pilot will have a much stronger effect than a novice).

Thank you very much for the explanation, I thought it was a bug.

[thewood1]

My understanding of notching is it only drops the lock. Because notching is flying perpendicular to the radar, not just the plane, unless you are flying a curve that follows the arc of the radar cone, notching is only a short term thing. The plane has to reaqcuire the enemy plane to "unnotch" the enemy plane.

That is just my interpretation of what I have seen around.

[Blast33]

ORIGINAL: Dimitris

There are already a number of factors at play, it's not nearly as simple as "turn perpendicular and you go poof".

At the technical level, what notching does is to merely reduce the apparent RCS of the detection target - sometimes substantially so, other times less so, depending on a few things. Thus, as a tactic, it is vulnerable to all the remedies against low RCS: Decrease distance, increase power, detect from multiple sides etc. It is also very sensitive to crew skill (an ace pilot will have a much stronger effect than a novice).

Unfortunately the RCS is at it's best at the front and worst at 90 degrees. So notching will not do that trick unfortunately.
For some radars notching brings the target under the minimum (pulse-doppler) speed threshold, so it will discard the the contact / lock. For fighters it is typically below 50-60 kts approaching speed.
This is done to filter out ground clutter and fast moving cars on highways etc. There are stories that in Germany they increased the doppler filter to 110 kts because of the fast moving Porsches on the autobahn. (don't know if it is true of a beer story ).
This was used to good effect on SA-6 sites in Iraq and the Kosovo war.

Track Via Missile systems (S-300 family / Patriot etc) don't have this problem. Because they have the missile data and the radar data and combine this to track the target.
Active missiles from aircraft can get target updates from the fire control radar. Or when it's active it has a different angle than the radar of the aircraft and will hit you.
What makes it more complicated is that airborne radars can move from left to right and are not totally fixed. So you have to be 80-100 degrees of the radar of the enemies aircraft and not of the flightpath...[X(]
How to program that???

There are probably more systems who can defeat this but who can tell more?

[thewood1]

Wings of Fury by Robert K Wilcox, Chapter 18, about tangling with two Mig-25s that "beamed" them.

"Suddenly, the Foxbats turned ninety degrees and executed a “beam” maneuver, heading west and perpendicular to the Eagles’ line of flight. As it was supposed to, the tactic banished the Foxbats from the four Eagle radars and broke Tollini’s lock."

They ended up killing them WVR as they were detected visually within 5 miles.

I know this is almost 30 years ago. But looking through some Osprey books on air combat in Yugoslavia, in the MidEast, in Iraq, and in training, beaming/notching was an expected tactic. In fact in the above book, the pilots weren't surprised by the beaming tactic and expected it.

I reached out to my old Marine pilot friend and he said in both the Harrier and Hornet, they were trained to immediately beam if they were at any disadvantage in a H2H approach. He said if the pilot is experienced, he can find the "slot". That's what he called it. He also said its not just about dropping lock. He said you have to also maneuver out of the cone of the radar or else the enemy will pick you back up fairly quickly. In older physical scan radars, it could take up to 30 seconds to reacquire. That gives you enough time to get out and gain advantage.

One of final comments was that beaming is hard to do. It requires knowing your environment and extensive training. I mentioned the Mig-25 story above and he said that the 25 got the best of the best Iraqi pilots. He would expect they could beam easily, especially if they had ever fought Iranian F-14s.

His last comment was that beaming modern radars, aircraft or SAM, is not easy, but can be done under the right circumstances. He didn't mention his definition of modern. He reiterated training and overall environment is critical to whether beaming can be done effectively. He said in a multi-flight engagement, beaming isn't the first maneuver he would choose. If the enemy flights are separated enough, you could be beaming into a worse situation.