F-14 Manual PD-STT Clarification

[Hovis]

Hi, slightly confusing part in the manual which I would very much like a little light on.

 

In the section regarding Pulse doppler single target track there a paragraph which reads:

 

"Unlike in pulse STT however the AN/AWG-9 can send missile guidance commands in pulse doppler STT enabling launch of AIM-7 and AIM-54 in pulse doppler mode. This is the mode with the greatest launch ranges for those missiles with the disadvantage, in the case of the AIM-54, of only being able to engage one target at a time."

 

At first glance my RIO and I both interpreted this to mean that AIM-7 and AIM-54 missiles can only be launched in pulse doppler mode as pulse does not supply missile guidance commands.

 

I know this is not the case in sim as we've tested splashing 29s with both sparrows and phoenixes firing from just P-STT and PD-STT and then switching to P-STT post launch... all missiles hit

 

Is the correct interpretation that PD-STT is capable of sending missile guidance "updates" to more accurately guide the missile and therefore increasing the missile's range?[/font]

[Naquaii]

Yes, in pulse the sparrow will use CW and have lesser range while the AIM-54 will just fly out along the radar line of sight until it find a target with its own seeker. The range of the AIM-54 in that mode is much less compared to in PD where it is also guided semi-actively.

[diditopgun]

Hi !

 

About Sparrow:

 

What's exactly the difference between CW guidance and PD STT guidance commands ?

 

If I use Pulse STT but MSL OPTIONS is set to SP PD what will happened ?

Same question with Pulse Doppler STT but MSL OPTIONS set to NORM ?

 

I don't well understand links between all those modes of guidance/buttons/switch, the manual is not clear enough.

[Naquaii]

If you're in P STT and set it to SP PD it will still use CW as it's not a PD mode.

If you're in PD STT and set NORM it will use CW.

[diditopgun]

OK thank you, that's clear now. :)

 

And about the differences between the two type of guidance?

[Naquaii]

Currently not really implemented but expect CW to have less range when we implement it fully. The PD guidance was developed to allow for greater range.

[diditopgun]

That's interesting, thank you very much for your explanation.

I hope all of this will be explain clearly as you do in future versions of the manual. I think it will be very helpful for people to understand.

[MRaza]

That's interesting, thank you very much for your explanation.

I hope all of this will be explain clearly as you do in future versions of the manual. I think it will be very helpful for people to understand.

 

Agreed, some aspects of the manual are either not fully explained or ambiguous.

[blkspade]

Honestly, the AIM-54 seemed not to be guiding in PD STT at all on initial release. This might have changed in a recent patch, but when my crew needs a one to reliably guide with STT we choose pulse. Its best used as a fail-over option for a fading TWS contact inside of 40nm that you've already launched on anyway, as you'd be pretty hard pressed to get a max range STT kill on anything with a RWR and any degree of intelligence.

 

The difference in range is probably even less relevant with the AIM-7 since its in-game effective range is pretty bad anyhow. I've seen the sparrow quoted as having 22nm max range with CW from an F-4, where as the missile should kinetically reach out to 38nm. The parameters for those shots are an especially rare occurrence though in DCS. CW range is almost never going to be your limiting factor.

[riboyster]

Think about it in terms of evasion as well. Chaff will be less effective in PD guidance, but notching will be effective.

[MRaza]

Yes, in pulse the sparrow will use CW and have lesser range while the AIM-54 will just fly out along the radar line of sight until it find a target with its own seeker. The range of the AIM-54 in that mode is much less compared to in PD where it is also guided semi-actively.

 

And what if SP PD is selected, but mid guidance I switch from PD-STT TO P-STT? Will the radar switch to CW guidance?

[Naquaii]

And what if SP PD is selected, but mid guidance I switch from PD-STT TO P-STT? Will the radar switch to CW guidance?

 

Depends on when and if we can model this, but IRL it seems the missile would be lost as it uses what is set at launch and switching to P-STT removes guidance. Not that this is not modelled currently.

[MRaza]

Depends on when and if we can model this, but IRL it seems the missile would be lost as it uses what is set at launch and switching to P-STT removes guidance. Not that this is not modelled currently.

 

ok cool and if set to NORM at launch, switching between PD-STT and P-STT wouldn't matter?

[jojo]

Usually, Fox 1 missiles are tuned to radar parameters before firing.

IRL I don’t think it would be a good idea to switch guidance mode with missile in flight.

 

This kind of advanced setting wasn’t used previously on any plane in DCS World, so maybe there is no consequence yet.

 

The Tomcat entered service with AIM-7E2, hence the pulse guidance. Then it got better AIM-7 with Pulse Doppler guidance.

 

From wiki:

 

With time, the early versions of all the missiles were replaced by more advanced versions, especially with the move to full solid-state electronics that allowed better reliability, better ECCM and more space for the rocket engine. So the early arrangement of the AIM-54A Phoenix active-radar air-to-air missile, the AIM-7E-2 Sparrow semi-active radar homing air-to-air missile, and the AIM-9J Sidewinder heat-seeking air-to-air missile was replaced in the 1980s with the:

- B (1983) and C (1986) version of the Phoenix,

- the F (1977), M (1982), P (1987 or later) for Sparrows

- with the Sidewinder, L (1979) and M (1982).

Within these versions, there are several improved batches (for example, Phoenix AIM-54C++).

[MRaza]

So I guess since it's not good to switch radar modes while guiding the missile, it's better to start with P-STT so you can't be notched

[Banzaiib]

Yes, in pulse the sparrow will use CW and have lesser range while the AIM-54 will just fly out along the radar line of sight until it find a target with its own seeker. The range of the AIM-54 in that mode is much less compared to in PD where it is also guided semi-actively.

 

You say that pulse reduces range, but in my MP experience, the AIM-54 rips 45 degrees AOA when it goes active, bleeds all of its energy, then never hits anything... so I'm just going to fire them all in pulse STT when possible to avoid this...

 

I know you guys (HB) have little if any control over missile guidance in MP... and I know there was just an update to it (4/1/2019), so I'll test it more...

[MRaza]

You say that pulse reduces range, but in my MP experience, the AIM-54 rips 45 degrees AOA when it goes active, bleeds all of its energy, then never hits anything... so I'm just going to fire them all in pulse STT when possible to avoid this...

 

I know you guys (HB) have little if any control over missile guidance in MP... and I know there was just an update to it (4/1/2019), so I'll test it more...

 

you cant use an aim54 in pulse stt, its gonna go active off the rail. AIM54 can only be guided in PD-STT and TWS

[MRaza]

Currently not really implemented but expect CW to have less range when we implement it fully. The PD guidance was developed to allow for greater range.

 

How much of a greater range?

[diditopgun]

29nm-->38nm

 

[Dudikoff]

Usually, Fox 1 missiles are tuned to radar parameters before firing.

 

The Tomcat entered service with AIM-7E2, hence the pulse guidance. Then it got better AIM-7 with Pulse Doppler guidance.

 

Technically, it's not pulse guidance, but CW as the radar is not doing the illumination as there's a separate antenna which paints the target and the missile's seeker is guiding towards the reflections. In this mode the missile's seeker has to be tuned to the CW frequency prior to the launch.

 

I guess the 7E models used conical scan seekers (only supports CW illumination), while the 7F introduced the monopulse seeker which supports both CW and PD illumination.

 

For the PD mode, I'd presume the seeker head is not really tuned per se, but WCS just sends one of the predetermined PD illumination channels (as set on the carrier aircraft by the ground crew) to the missile (as the 7F had digital electronics).

Edited April 2, 2019 by Dudikoff

[MRaza]

Depends on when and if we can model this, but IRL it seems the missile would be lost as it uses what is set at launch and switching to P-STT removes guidance. Not that this is not modelled currently.

 

Another question: is there a reason that PD guidance is not automatically used when in PD-STT? It seems like it'd make more sense if the designers made it this way, don't see any reason to have someone locked in PD-STT and want to use CW guidance over PD

[Karon]

Radar noob here; how does the CW behaves compared to PD when the target defends itself by means of nothing and other manoeuvres? When is better to use PD instead of CW then?

[blkspade]

Radar noob here; how does the CW behaves compared to PD when the target defends itself by means of nothing and other manoeuvres? When is better to use PD instead of CW then?

 

PD is better solely for range, which is largely irrelevant against anything likely to maneuver (fighters with RWR). In terms of sparrow employment, max range of around 38nm won't hit most targets unless they are stupid. P-STT which results in CW, being notch resistant, makes it the better choice at any range you could realistically expect to get a kill against a fighter.

[MRaza]

PD is better solely for range, which is largely irrelevant against anything likely to maneuver (fighters with RWR). In terms of sparrow employment, max range of around 38nm won't hit most targets unless they are stupid. P-STT which results in CW, being notch resistant, makes it the better choice at any range you could realistically expect to get a kill against a fighter.

 

And since you have a chance of being notched in PD, I would personally always use CW so there's no chance of that

[Karon]

Good points, thanks folks.