correct as is HACQ/LACQ are much harder to lock heli than other ACM modes

[FrostLaufeyson]

Just check the trk files, you can only use the HMD to lock on to helicopters when you are about to crash on them. Not sure if this is normal, but from my understanding HACQ and BST should work similarly.

 

Off topic:

Originally I was exploring the difference between NORM and WIDE in RWS, but I found that the F18's radar, can't detect the helicopter anyway. Hope ED can shed some light on what exactly this NORM/WIDE has changed.

So I decided to test how far the ACM can lock onto the helicopter, so I found this problem.

HACQ lock heli.trk LACQ lock heli.trk Other ways lock heli.trk

[BIGNEWY]

Thanks we have asked the team to check it. 

[Lord Vader]

Hey @FrostLaufeyson

There was a recent change on the radar detection capabilities regarding radial speed to bring it closer to real life characteristics. As such, aircraft within lower radial speeds are supposed to be harder to track while flanking. In your tracks, this is observed, with those helicopters with radial speeds as low as 25kts.

If you attempt to lock head-on or chasing them, you will notice it becomes much easier. I was also able to lock them farther with WACQ mode or even using just the sidewinder seeker uncaged.

[FrostLaufeyson]

2022/12/21 PM6点10分，Lord Vader说：

Hey @FrostLaufeyson

There was a recent change on the radar detection capabilities regarding radial speed to bring it closer to real life characteristics. As such, aircraft within lower radial speeds are supposed to be harder to track while flanking. In your tracks, this is observed, with those helicopters with radial speeds as low as 25kts.

If you attempt to lock head-on or chasing them, you will notice it becomes much easier. I was also able to lock them farther with WACQ mode or even using just the sidewinder seeker uncaged.

I think you may have misunderstood something. This question has nothing to do with hot, flank, or cold. I was able to lock directly to the helicopter at 10 nm using BST with the HMD off (flank does make that distance shorter), but with the HMD on and using HACQ, I have to close to less than 1 nm to be able to lock the helicopter.

My question is, shouldn't the locking distance of HACQ be the same as BST?

[Lord Vader]

I saw pretty much the same limitations in radial speed using the HUD boresight compared to the HMD, to be honest. There should be no difference, both approx. 10 nm.

But, again, I don't think the issue here is distance but aspect, try your tracks again, but attempt to look towards the targets while they're head on or being chased and you can lock them at fairer distances.

[MARLAN_]

36 minutes ago, Lord Vader said:

I saw pretty much the same limitations in radial speed using the HUD boresight compared to the HMD, to be honest. There should be no difference, both approx. 10 nm.

But, again, I don't think the issue here is distance but aspect, try your tracks again, but attempt to look towards the targets while they're head on or being chased and you can lock them at fairer distances.

Should aspect matter here? Should only be closure as far as I know, and in the case of fighters RCS generally increases as aspect angle increases. There are some good public documents I can send to you about the topic if you're interested.

[Lord Vader]

3 hours ago, MARLAN_ said:

Should aspect matter here? Should only be closure as far as I know, and in the case of fighters RCS generally increases as aspect angle increases. There are some good public documents I can send to you about the topic if you're interested.

Lost in translation here, but I think it's the best word to use in what I was saying, as in, locking from the front or the back of the target. And yes, it does affect the closure rate.

If you have documentation, make sure it is public available data and please send to @BIGNEWY, referring this thread. 

Thank you. 

[Hulkbust44]

On 12/22/2022 at 2:41 PM, Lord Vader said:

Lost in translation here, but I think it's the best word to use in what I was saying, as in, locking from the front or the back of the target. And yes, it does affect the closure rate.

If you have documentation, make sure it is public available data and please send to @BIGNEWY, referring this thread. 

Thank you. 

We're also talking about a helicopter here, however correct me if i'm wrong, DCS doesn't model the rotors when it come to RCS. If it did, at these ranges you really couldn't lose the target due to velocity gates. 

Paging @Beamscanner (when it's not Dec 24th...)

[Beamscanner]

• Helos typically fly at speeds inside the main beam clutter notch filter (<~100 knots)
• Helo detection is thus primary achieved via the rotor blades, due to their doppler shift.
• The best reflector on a helo is its tail rotor.
  • its RCS is higher than the main blades when a vertical polarization is used (ie Fighter Radars). The main blades have a higher RCS when a horizontal polarization is used (ie some ground based Radars) (Reference)
  • It also spins faster than the main blades and thus its doppler shift is more likely to sit in the clutter free doppler spectrum (or closer to it where the sidelobe clutter is weak)
  • Thus, the best detection aspect is from behind the helo (clear LOS on tail blade; tail blade has high relative velocity from this aspect, thus good doppler)
    • (simulation of Helo RCS, though the authors unfortunately did not mention the polarization used. Ignore the RCS reduction techniques modeled and look at their default RCS. Keep in mind that this paper is on RCS in general (ie including ground radars) not RCS against a fighter (primary detecting doppler). 
  • From the front aspect, you have no LOS on the tail rotor. 
  • From the side aspect, you have LOS on the tail (thus high vertical pol. RCS), but the doppler shift is not significant bc the relative velocity from this angle is minimal.
• While it may seem as though the blades have a very small RCS (they do), they also scatter their doppler shifted RF across the helo's fuselage which in turn scatters some of this RF back to the radar. (ie multipath effects between the rotors and fuselage significantly increase the RCS of the helo).

Edited December 29, 2022 by Beamscanner

[BIGNEWY]

We are taking another look at this internally. But I have no news to share currently 

thanks