Upcoming RDI Radar changes

[Zeus67]

The TWS bug is an antenna recovery bug. The antenna recovers normally when the elevation is above the aircraft's plane. If it is below the aircraft's plane it takes its sweet time returning. The bug is worse when you do a roll.

 

If you do a hard roll the antenna suddenly finds itself below the aircraft's plane and out of position and loses the target due to the long recovery time. In fact tests shows that it does at least two full sweeps before it returns to its position. It manages to keep the target inside the search cone if you do slow and gentle rolls, but then if you are in a combat situation that is not going to happen very often.

 

Since this bug affects basic antenna movements I cannot fix it. ED has to do that. I'll drop a reminder.

 

This bug affects both RWS and TWS. It does not affect STT because it uses a different system to keep a target in sight.

[GGTharos]

Just a curious question here Zeus:

 

Are you completely dependent on ED's code for this, or can you program a time-out feature into your TWS display such that a temporary loss of lock doesn't even register on the display.

 

A longer loss would cause your track to blink and alter the display on the HUD as well. The track would not be dropped until you go through the complete set of (configurable) timeouts for it.

 

The TWS bug is an antenna recovery bug. The antenna recovers normally when the elevation is above the aircraft's plane. If it is below the aircraft's plane it takes its sweet time returning. The bug is worse when you do a roll.

 

If you do a hard roll the antenna suddenly finds itself below the aircraft's plane and out of position and loses the target due to the long recovery time. In fact tests shows that it does at least two full sweeps before it returns to its position. It manages to keep the target inside the search cone if you do slow and gentle rolls, but then if you are in a combat situation that is not going to happen very often.

 

Since this bug affects basic antenna movements I cannot fix it. ED has to do that. I'll drop a reminder.

 

This bug affects both RWS and TWS. It does not affect STT because it uses a different system to keep a target in sight.

[Zeus67]

Just a curious question here Zeus:

 

Are you completely dependent on ED's code for this, or can you program a time-out feature into your TWS display such that a temporary loss of lock doesn't even register on the display.

 

A longer loss would cause your track to blink and alter the display on the HUD as well. The track would not be dropped until you go through the complete set of (configurable) timeouts for it.

 

I'm totally dependent on ED on this. All I do is ask the radar if the target is still there. If it isn't then it is cleared from the target list.

 

I'll see about the time-out, but I need to finish other stuff before i deal with this.

[GGTharos]

I understand.

 

The solution is to build a track memory system on top of this. Up to you how you want to handle it obviously, but from your description it is possible on your end ... just not necessarily simple. :)

[Zeus67]

I understand.

 

The solution is to build a track memory system on top of this. Up to you how you want to handle it obviously, but from your description it is possible on your end ... just not necessarily simple. :)

 

The RDO button in the PCA does this:

 

 

The lost track becomes yellow and it remains for a few seconds more. Since I don't know how long I can use the F-15C standard: 8 seconds. Hopefully the radar will reacquire by that time and turn it back to green.

 

But as you said this will be a bit complex to code, and I have another difficulty to deal with: the VTB is very near the system limit of elements it can show.

[GGTharos]

Hi Zeus,

 

I can give you reasonably deep description of what the F-15 does, and this is late 80's to early 90's stuff so you may be able to apply the ideas if not the numbers.

 

Here goes:

 

For STT:

 

If the lock is lost, there is an immediate track recovery attempt for 1.5 sec (I think, I'll get you accurate numbers later). Up to the end of this 1.5 sec the pilot doesn't know anything about this - it's completely automated and the loss of lock could be due to antenna movement because of heavy maneuvering or turbulence or something. Who knows :)

Usually the recovery here is a 3x3 mini-raster.

 

If the lock is not recovered after 1.5s, then:

 

The radar goes into 'Memory Mode', running a possibly expanding mini-raster along the predicted track movement.

 

The amount of time it takes for this depends on a couple of things:

If you are in an AACQ mode, IIRC it's 3-4 seconds.

 

If you are in RWS or other BVR mode, the recovery attempt time depends on your VSD distance scale (or target range when lock was lost, don't quote me on this one, I have to re-read the docs for accurate answer :) ). The further away, the longer the attempt.

 

For TWS:

 

In all cases IIRC, a fully instantiated track is lost during a sweep, then:

 

In the F-15 the frame store is basically the number of sweeps - so if you set the frame store to 3, that would be 6 seconds timeout from the last sweep. At this point the track starts timing out for a configurable amount of time IIRC. The total is around 12-13 seconds.

 

The timed-out track is indicated by making that track blink until it is detected again or dropped.

 

Regarding the symbols in the VTB - do you mean RL limitation or coding limitation?

 

The lost track becomes yellow and it remains for a few seconds more. Since I don't know how long I can use the F-15C standard: 8 seconds. Hopefully the radar will reacquire by that time and turn it back to green.

 

But as you said this will be a bit complex to code, and I have another difficulty to deal with: the VTB is very near the system limit of elements it can show.

[Zeus67]

Regarding the symbols in the VTB - do you mean RL limitation or coding limitation?

RL limitation as in it won't accept more elements. I feel like balancing on a tightrope whenever I am working on it. :smartass:

[GGTharos]

Ahh I see :)

 

I have seen some tricks on RWRs and other radar displays to get around this limitation:

 

Compositing symbols (ie. small symbols are places on larger symbols to augment them)

Brightness changes and dashed line. Neither counts as a different symbol in terms of storing the shape.

[microvax]

Is the RDO one implemented or lemme ask like this, any of the switches on the VTB except the toggle reference waypoint ?

 

Also is the radar memory switch on the radar panel or doppler filter setting planned to be implemented or is DCS radar model simply not accurate enough to implement it in a sensible way.

[Frostie]

No, Zeus just confirmed that TWS still has a bug that causes you to drop targets shortly after you bug them, especially if you maneuver or roll. He said it's a bug that ED has to fix.

 

Losing scanning track happens to all radars in DCS when the aircraft is abrubtly moved, this could well be a feature.

 

TWS is not a direct display to what the radar sees, it is a predicted track file that uses history and prediction to show contacts. This is rightly modelled by DCS as a scanning profile rather than a hard lock profile. If it was the same as STT then it wouldn't be TWS it would be an unrealistic STTWS.

What Rbs Model is lacking is the history to keep a lock when tracking is lost, it seems the F15 has this feature.

[VTJS17_Fire]

Question: Does the Mirages Radar has a receive-only mode?

 

In the emission mode, the impulse Radar of the Mirage sends (active) Radar impulses and measures the Radar return (distance, Speed of the target and so on). So it uses its active operation mode, which can also used for HOJ shots with the Super 530D.

 

Real life: In the receive-only mode, it should also be able to see active signals from other emitters, like jammers. So, AFAIK, the Mirage should be able to see strobes (ECM signals) wihtout sending own Radar signals. It uses only the returnbreak-feature (German: Empfangszeit/ Tastpause) of its Radar. This would mean, I could shot HOJ with the Radar in standby mode.

 

Is the (DCS) Mirage capable of this or is this feature planned?

 

 

Thanks in advance,

Fire

[jojo]

I never heard of this feature. It doesn't mean it doesn't exist, but ECCM modes are highly classified. So nothing available yet to support this request.

 

However, the priority is to know when you reach burn through range to shoot your Fox 1 Super 530D, and you wouldn't know in receive only mode.

Edited October 27, 2016 by jojo

[Dusty [CPC]]

Question: Does the Mirages Radar has a receive-only mode?

 

In the emission mode, the impulse Radar of the Mirage sends (active) Radar impulses and measures the Radar return (distance, Speed of the target and so on). So it uses its active operation mode, which can also used for HOJ shots with the Super 530D.

 

Real life: In the receive-only mode, it should also be able to see active signals from other emitters, like jammers. So, AFAIK, the Mirage should be able to see strobes (ECM signals) wihtout sending own Radar signals. It uses only the returnbreak-feature (German: Empfangszeit/ Tastpause) of its Radar. This would mean, I could shot HOJ with the Radar in standby mode.

 

Is the (DCS) Mirage capable of this or is this feature planned?

 

 

Thanks in advance,

Fire

Afaik, this is not possible on a pulse doppler radar such as the RDI.

You'd need an AESA radar for this sort of jamming processing.

 

Tactically speaking, as JoJo said, there's be little point shooting 530s HOJ with no idea of range to target (burnthrough, GCI, ...)

Edited October 28, 2016 by Dusty

[VTJS17_Fire]

Afaik, this is not possible on a pulse doppler radar such as the RDI.

You'd need an AESA radar for this sort of jamming processing.

Negative. That's the Basic principle of a pulse (doppler) Radar. It sends short, high energy pulses and waits for the return (short version). You can read about this technique at www.radartutorial.eu.

 

Tactically speaking, I had some kills with HOJ shots using the AIM-7. This is in DCS possible, because some pilots switch their music on and fly straight on. The FC 3 planes can stay with ECM on, all the time. Yeah, it's luck to one side, using the inexperience of new Players of the other side.

 

On the other Hand, possbile HOJ shots can prevent the enemy from using their jammers.

 

So, HOJ shots and tactics have their right to exist.

[red_coreSix]

It wouldn't work like that in RL. HOJ is only really possible in DCS because we have very poor jammers modeled. They are pretty much non-directive noise jammers in barrage mode. They jam all the time not really directed against any specific target. A realistically modeled jammer would stop jamming once the emitter it's trying to jam (the RDI in this case) ceases to emit. A receive only mode isn't really feasible with a SPJ in RL, they never jam offensively, only in reaction to a threat.

[GGTharos]

It's quite possible - the F-15 does this with its SNIFF mode since the 80's at least. It's up to the manufacturer to implement such things though.

 

Afaik, this is not possible on a pulse doppler radar such as the RDI.

You'd need an AESA radar for this sort of jamming processing.

 

Tactically speaking, as JoJo said, there's be little point shooting 530s HOJ with no idea of range to target (burnthrough, GCI, ...)

[VTJS17_Fire]

they never jam offensively, only in reaction to a threat.

Except dedicated jammer aircraft, such as the EA-6B "Prowler" which is also used as a broadband jammer, to prevent any clear Radar Pictures at all.

 

They fly on station and jamm all the way, when the real (attack) mission is underway. Good example is operation El Dorado in the late 1980s. I know, there is at least top cover with CAPs, but HOJ shots at These aircraft are very likely, if your own air force is able to take-off and get in rough range.

[red_coreSix]

Except dedicated jammer aircraft, such as the EA-6B "Prowler" which is also used as a broadband jammer, to prevent any clear Radar Pictures at all.

 

They fly on station and jamm all the way, when the real (attack) mission is underway. Good example is operation El Dorado in the late 1980s. I know, there is at least top cover with CAPs, but HOJ shots at These aircraft are very likely, if your own air force is able to take-off and get in rough range.

 

That's why I said SPJ (self protection jammer) :smilewink:

But still, even a dedicated EW aircraft doesn't have to use noise jamming, in fact it's pretty unlikely that they would against MSA antennas like the RDI. HOJ wouldn't work against deceptive ECM, at least not when it's done right.

Edited October 28, 2016 by red_coreSix

[GGTharos]

You can expect SoJs to use even more fun track-breaking methods for self-defense than SPJs.

 

HoJ is seriously misunderstood - again, it's a fallback launch mode, and if you are lucky there's a jammer out there that you can actually home in on - but that's somewhat unlikely given that it is likely to be sweeping through frequencies that your missile seeker can't even respond to.

 

Except dedicated jammer aircraft, such as the EA-6B "Prowler" which is also used as a broadband jammer, to prevent any clear Radar Pictures at all.

 

They fly on station and jamm all the way, when the real (attack) mission is underway. Good example is operation El Dorado in the late 1980s. I know, there is at least top cover with CAPs, but HOJ shots at These aircraft are very likely, if your own air force is able to take-off and get in rough range.

[Dusty [CPC]]

Negative. That's the Basic principle of a pulse (doppler) Radar. It sends short, high energy pulses and waits for the return (short version). You can read about this technique at www.radartutorial.eu.

 

Tactically speaking, I had some kills with HOJ shots using the AIM-7. This is in DCS possible, because some pilots switch their music on and fly straight on. The FC 3 planes can stay with ECM on, all the time. Yeah, it's luck to one side, using the inexperience of new Players of the other side.

 

On the other Hand, possbile HOJ shots can prevent the enemy from using their jammers.

 

So, HOJ shots and tactics have their right to exist.

I'm not talking about the DCS world where jamming is a single button broadband noise.

A pulse doppler radar is not processing any returned frequency out there, it's tailored to process (and filter!) it's own frequency modulo a doppler shift.

So besides an adaptative (defense mode for capable fighters) or broadband (only a few a/c capable) jamming, I'm genuinely curious on how and to what purpose the SNIFF mode is used (GG?)

 

Tactically, I'll stick to my guns and repeat that HOJ with no other way to determine distance to target is ridiculous. HOJ is most used when your missile is being jammed in-flight, or you already knew you were in the firing envelope pre-launch. Didn't say the tactics didn't exist.

[GGTharos]

I don't know what tactics would be used with SNIFF. This mode will simply display signals picked up by the radar within its frequency capability. Doppler isn't processed since you don't have an input signal from your own radar.

 

As for HoJ, I think you pretty much got it right.

 

So besides an adaptative (defense mode for capable fighters) or broadband (only a few a/c capable) jamming, I'm genuinely curious on how and to what purpose the SNIFF mode is used (GG?)

 

Tactically, I'll stick to my guns and repeat that HOJ with no other way to determine distance to target is ridiculous. HOJ is most used when your missile is being jammed in-flight, or you already knew you were in the firing envelope pre-launch. Didn't say the tactics didn't exist.

 

 

 

Sent from my P01MA using Tapatalk

[Azrayen]

So SNIFF = RWR (basically)?

[Bacab]

So SNIFF = RWR (basically)?

If I understood correctly what GG said it's different because it shows everything in the bandwidth of the radar receiver while the RWR filters to only show potential radar emissions. So jamming won't be seen on the RWR but will be seen in SNIFF.

[GGTharos]

As Bacab said, it's a little more than that, but I suppose very similar. SNIFF is described in detail in a secret -34 supplement, so I don't know what it does exactly - ie. symbols etc.

 

So SNIFF = RWR (basically)?

[Azrayen]

Why would the RWR not be able to scan (= display) the same freq as the radar?

 

Wouldn't the jammer jams this frequency range?