stealthiness of RWS vs TWS in F18

[skypickle]

Since The radar "power" (effective emitted energy) is both the same for TWS and RWS, why does the target get different warnings in their RWR?

 

I read this thread

 

but it confused more than explained.

It stated  'For TWS you can lock on and fire on a target with a "soft lock" and the target will be none the wiser '.

I am not talking about STT where the radar focusses on the target with a hard lock.

But why would RWS  alert the enemy (especially using LTWS mode) and TWS not?

[MARLAN_]

If you employ in STT the bandit will receive a track indication (from STT) and then a missile warning once the AMRAAM goes active.

If you employ in TWS the bandit will only have a search indication, and then a missile warning once the AMRAAM goes active.

For the record, "soft/hard lock" isn't a thing, the only lock is STT. In TWS you designate targets (L&S, DT2).

[WobblyFlops]

2 minutes ago, skypickle said:

is both the same for TWS and RWS, why does the target get different warnings in their RWR

To the best of my knowledge this isn't the case and this is also explained in the thread you linked. Designating someone as L&S is not any kind of lock, it doesn't directly do anything to the radar by itself, it's just telling the mission computer that 'hey, this track is important'. The result will be that the designated track will have higher priority, the jet will give steering cues against that target, if you launch a missile it will guide towards that target and so on.

 

The interaction with the radar is that in TWS AUTO and BIAS modes, the radar will work as hard as it can to keep the L&S as long as possible while also maximizing the other trackfiles it can keep. (once it gets implemented fully it will be even more effective) But you're not changing the radar emissions, the amplitude of the beam will still be varying and not constant. There isn't any shift in frequency or anything that's detectable. Once you go STT, sure, the target will pick up that your radar is gimballed directly to his aircraft and the amplitude of the beam will remain constant and won't vary, which is a telltale sign of a 'hard lock'.

 

The Viper is a bit more complicated. If you designate from RWS you'll enter SAM mode. In DCS this won't result in a spike but some people argue that it should. Since the exact capabilities of specific RWRs is a very closely guarded secret, we can't really decide either way, both sides have reasonably good arguments but as it stands now in DCS, SAM mode in the Viper won't result in a spike either.

[skypickle]

thank you for your words but that does not explain why RWS gives an RWR warning and TWS does not.

[Tholozor]

Since when does RWS provide launch warning, and why are we using a search mode for missile attack? The trackfile update rate would be terrible.

Edited December 5, 2021 by Tholozor

[skypickle]

@Tholozor  this comment

suggests RWS gives a warning to the target but TWS does not. It is not a launch warning but I think it refers to the the fact that the target is aware it is being illuminated by the radar. My understanding is that RWS goes directly to the display but TWS goes to a computer that collates data and assigns little HAFU symbols.  

Chuck's guide says " a TWS launch with an AMRAAM will not provide the enemy aircraft with a radar lock and launch indication. As such, the first warning the enemy pilot will likely get is when the active radar seeker of the AIM-120 missile goes active near the target." I infer that an AMRAAM launch in RWS does warn the target.

 

Since radar requires the emission of EM energy, how can a RWR receiver not detect TWS?

 

[Tholozor]

12 minutes ago, skypickle said:

Since radar requires the emission of EM energy, how can a RWR receiver not detect TWS?

That's not a thing. If the radar is emitting, the RWR will see it no matter what mode the radar is operating in. The only way for the RWR to not show the radar at all is for the radar to either be in a silenced, non-emitting mode, or in an RWR blind-spot, which is fairly difficult to achieve (depending on the RWR).

If the radar goes STT, the RWR will send an alert it's being locked. If the contact is only designated as L&S eithout being in STT, it will not send an alert, but the RWR will still show the radar is there. It makes no difference if it's RWS or TWS.

[WobblyFlops]

14 minutes ago, skypickle said:

suggests RWS gives a warning to the target but TWS does not.

RWS cannot support missiles. You either fire from STT or TWS.

 

15 minutes ago, skypickle said:

It is not a launch warning but I think it refers to the the fact that the target is aware it is being illuminated by the radar.

Every radar mode shows up on every RWR in DCS. To get around that, you'd need LPI radars, which are classified and way too new to be modelled. So TWS, RWS, VS or any other search mode will show up on the RWR regardless. But it's not going to show neither a radar lock nor a missile warning, unless you transition to STT.

 

17 minutes ago, skypickle said:

My understanding is that RWS goes directly to the display but TWS goes to a computer that collates data and assigns little HAFU symbols.  

As far as I'm aware, in DCS there is no RWR contribution to trackfiles. You can have the detected radars show up on your MSI displays, the RWR scope, the HUD or the JHMCS. 

 

18 minutes ago, skypickle said:

I infer that an AMRAAM launch in RWS does warn the target.

Chuck's guide also notes on page 198 that you cannot launch missiles from RWS. 

[Bunny Clark]

For any aircraft in DCS there are three levels of RWR alert:

A Search Warning alerts the pilot that their aircraft is being illuminated periodically by a radar in a search or scan mode. This could be any air radar in RWS or TWS mode, or any ground based search, surveillance, or early warning radar, or an airborne search radar like an AWACS. In western aircraft this is generally noted by a symbol on the RWR that is not highlighted or called out in any way. 

A Track Warning (or Spike) alerts the pilot that their aircraft is being illuminated continuously by a tracking or fire control radar. This could be an air radar in STT, or the guidance radar of a SAM battery. It indicates that the aircraft is being targeted, and is generally the precursor to a weapon launch. The RWR will show this by highlighting the aircraft or surface system than is tracking you.

A Launch Warning alerts the pilot that a radar is supporting missile guidance on their aircraft. This could be a semi-active missile like a Sparrow or R-27, in which case the warning will come from the launching aircraft. Most SAMs are also semi-active and will highlight the system that is launching. Or it could be an active radar missile like an AMRAAM or R-77, in which case the warning will come from the missile itself. 

Of note, both RWS and TWS themselves provide the exact same warning to the target. The "sneaky" aspect to a TWS launch when using an active missile like an AMRAAM is that the target will only see a Search Warning from the launching aircraft, then suddenly get a Launch Warning from the AMRAAM when it goes active. You essentially skip a step in the warning escalation, and the Launch Warning itself will never identify the launching aircraft. The actual tactical advantage of this I feel is pretty overrated, any decent pilot is going to recognize when an enemy aircraft is attacking them, and when they're within launch range for an active radar missile defend themselves appropriately. 

[Ahmed]

Launch warning is triggered by a discernable mode switch (change of PRF, detection of CW/PD illuminator, detection of command uplink...). Thus, an AIM-7 launch for example can "easily" be detected. An AIM-120 launch, regardless of being launched in STT or TWS, should likely not produce any launch warning on the target prior to the missile going active, for the same reasons above (STT would however still produce a lock warning). I think that most of this is actually correctly modeled in DCS.

[skypickle]

thank you all, especially Bunny. 

[Hulkbust44]

you cannot launch missiles from RWS. 

Are you sure? That makes no sense as RWS in the Hornet is basically just TWS without limitations. The trackfiles are always being generated and as I understand it TWS HAFU and RWS TUC are exactly the same when L+S. The difference is scan centering and refresh rate.

Of course, MSI is *supposed* to create a trackfile regardless of radar contribution. A missile launch would command AUTO scan centering anyway.

Mobius708