Questions about FCR Radars in DCS

[VTJS17_Fire]

Hi,

 

I currently read eBooks and articles about Radar technology, scan and antenna types. While reading here and there, I wondered which scan (and antenna) types are modelled in DCS?

 

In reality, modern 4th generation fighter are usually equipped with a pulse Radar and a parabolic dish or AESA antenna. For instance, the F-15C, F/A-18C and M-2000C.

 

The MiG-21bis with its RP-22 radar, in contrast, uses conical scanning and a

twist-cassagrain antenna. Because of that, the look-down, shoot-down capabilities are limited. I didn't understand why exactly yet, but it's a fact.

 

I also read, there are older fighters with continuous wave Radars and Monopulse antennas. But I can't find any sources, which fighters/ Radars use(d) such technologies and antennas. And I read, some of this older Radars were immune to some (or most) jamming techniques (IIRC, it was the continuous wave), as well.

 

Is anybody fit in this topic and can help me a little bit to understand it? Thanks in advance.

 

 

Kind regards,

Fire

[Bushmanni]

Most modern radars use slotted array antenna, not parabolic dish. Here's a F-16 radar antenna for example.

 

 

There's single transceiver module powering the antenna and the radar energy is routed to each individual hole through wave guide tubes. In essence slotted array uses interference patterns like AESA or PESA to shape the beam but there's no phase control for each slot so the beam shape and direction is fixed. In PESA each slot has phase controller that can alter the phase of the signal emitted or received from that individual slot to direct the beam but the antenna is still powered by single transceiver. In AESA each slot has it's own transceiver module that can alter both phase and amplitude of the single slot. AESA transceiver module can alter the phase much faster and hence can steer the beam faster and this is simply due to the physical properties of the materials used in AESA modules and PESA phase controllers. Individual slot amplitude control also allows more sophisticated methods for beam shaping that have lower sidelobes and hence less clutter and thus better detection sensitivity.

 

Look down/Shoot down capability is tied to Doppler processing. Without it you can't distinguish static ground clutter from moving targets.

[VTJS17_Fire]

In reality, modern 4th generation fighter are usually equipped with a pulse Radar and a parabolic dish or AESA antenna. For instance, the F-15C, F/A-18C and M-2000C.

 

 

Most modern radars use slotted array antenna, not parabolic dish. Here's a F-16 radar antenna for example.

As you can see, I already wrote that. But thanks for the detailed explanation. But the radar signal technology - in general - is the same: It sends a radio wave, wait a death time and gets the echo.

 

 

Look down/Shoot down capability is tied to Doppler processing. Without it you can't distinguish static ground clutter from moving targets.

Ok, thanks. I read that a few minutes before.

 

But: Has the (DCS) MiG-21bis does not also have an clutter filter (Declutter switch) to hide ground/ cloud clutter?

[drPhibes]

As you can see, I already wrote that. But thanks for the detailed explanation.

 

Nope. You wrote AESA antenna, whish isn't the same thing as a slotted wavegudie antenna.

[VTJS17_Fire]

Nope. You wrote AESA antenna, whish isn't the same thing as a slotted wavegudie antenna.

Yep, you're right. Sorry. I checked the picture from Bushmanni again and saw the difference between these two. Thanks for the hint.

[LuSi_6]

for the Mig21: reason for no shoot down/ look down is not the antenna, it's because it's not a doppler radar

[SkateZilla]

AESA = Advanced Electronically Scanned Array.

Which are only Found in Gen 4.0 Upgraded, 4.5+ and 5th Gen Fighters

 

Consisting of:

F/A-18E (Lot 28 or Later),

F/A-18F (Lot 28 or Later),

E/A-18G,

F-16E/F (Block 60)

F-16V (Block 20 Upgrade)

B-1B

F-22A

F-35A

F-35B

F-35C

E-2D

Boeing 737 AEW/C

MQ-4C

F-15C w/ AN/APG-63V3

F-15SG

F-15E (Later Blocks)

B-2

Raytheon Sentinel

JAS-39E,

Eurofighter

MQ-9

Mitsubishi F-2

Mitsubishi SH-60

T-50 Prototypes

And J10/11/15/16 with Updated Blocks

And Likely other aircraft that are getting M.L.U.s

 

No Aircraft in DCS Actually Model the AESA Radar afaik, at least not to the extent of Professional System Modelling of DCS Aircraft.

E-2D Uses AN/APS-138 (instead of the AN/APY-9), And Even the AI DCS:F-15E uses the AN/APG-63 Sensor.

 

Which is Scripted as:

["AN/APG-63"] =
       {
           type = RADAR_AS,
           scan_volume =
           {
               azimuth = {-60.0, 60.0},
               elevation = {-30.0, 30.0}
           },
           centered_scan_volume =
           {
               azimuth_sector = 30.0,
               elevation_sector = 30.0
           },
           max_measuring_distance = 265000.0,
           detection_distance =
           {
               [HEMISPHERE_UPPER] =
               {
                   [ASPECT_HEAD_ON] = 88400.0,
                   [ASPECT_TAIL_ON] = 44000.0
               },
               [HEMISPHERE_LOWER] =
               {
                   [ASPECT_HEAD_ON] = 88400.0,
                   [ASPECT_TAIL_ON] = 44200.0
               }
           },
           lock_on_distance_coeff = 0.85,
           velocity_limits =
           {
               radial_velocity_min = 100.0 / 3.6,
               relative_radial_velocity_min = 100.0 / 3.6,
           },
           scan_period = 5.0,

       },

Edited September 15, 2016 by SkateZilla

[VTJS17_Fire]

Are such scripts used in SSM (AI/ flyable) only or in ASM as well? For instance, in the M-2000C.

[GGTharos]

Hi,

 

I currently read eBooks and articles about Radar technology, scan and antenna types. While reading here and there, I wondered which scan (and antenna) types are modelled in DCS?

 

Explicitly, none. You can kind of model them by changing detection and lock ranges and time to lock, tracking stability, resistance to ECM/EMI etc.

 

In reality, modern 4th generation fighter are usually equipped with a pulse Radar and a parabolic dish or AESA antenna. For instance, the F-15C, F/A-18C and M-2000C.

 

Nope. Parabolic is old news. It's parabolic (MiG-21, F-5, F-4), cassegrain (may or may not be parabolic - used by MiG-29/Su-27), and slotted array planar (what the F-15C, F-18, etc use)

 

The MiG-21bis with its RP-22 radar, in contrast, uses conical scanning and a

twist-cassagrain antenna. Because of that, the look-down, shoot-down capabilities are limited. I didn't understand why exactly yet, but it's a fact.

 

Because it doesn't use PD discrimination. It has little to nothing to do with the other things.

 

I also read, there are older fighters with continuous wave Radars and Monopulse antennas. But I can't find any sources, which fighters/ Radars use(d) such technologies and antennas. And I read, some of this older Radars were immune to some (or most) jamming techniques (IIRC, it was the continuous wave), as well.

 

Is anybody fit in this topic and can help me a little bit to understand it? Thanks in advance.

 

 

Monopulse allows you to find the target location with a single pulse instead of scanning around it to detect where exactly in the lobe the target is positioned (con-scan).

Pretty much everything built in the late 70's and after has some form of monopulse antenna.

[VTJS17_Fire]

Ok, thanks. But are there aircraft (Radars) in DCS which are more difficult to jam? Or is jamming generic?

 

In the past, we had only (steady) noise jamming for all aircraft. The A-10C is limited to its lock breaker and can't jam continously as far as I remember. Then came the M-2000C with deception jamming (false target generator). Sadly, its simulated by the Radar of the M-2000C, not by the ECM of the target. So, only the M-2000C see false targets, while all other aircraft with Radar see strobes.

 

And IIRC, the DCS F-117 is harder to detect, so stealth is also modelled to a certain point. Right?

[GGTharos]

Ok, thanks. But are there aircraft (Radars) in DCS which are more difficult to jam? Or is jamming generic?

 

It's all pretty generic - all jammers are generally represented as range jammers, ie. generating false targets along their azimuth line. There are no emitter limits in terms of AZ/EL etc.

 

In the past, we had only (steady) noise jamming for all aircraft. The A-10C is limited to its lock breaker and can't jam continously as far as I remember. Then came the M-2000C with deception jamming (false target generator). Sadly, its simulated by the Radar of the M-2000C, not by the ECM of the target. So, only the M-2000C see false targets, while all other aircraft with Radar see strobes.

 

The range jammer is also generating false targets. Combine it with an AZ (sidelobe) jammer and you get a blanked out scope probably :D

 

And IIRC, the DCS F-117 is harder to detect, so stealth is also modelled to a certain point. Right?

 

I think most elements of the basic radar equation are simulated. The F-117 has a low RCS in game. You'll notice large aircraft have a large RCS.

[Eihort]

I'll just leave this here because it has lots of good info.

 

http://www.ausairpower.net/APA-Flanker-Radars.html#mozTocId612676

[sobek]

AESA = Advanced Electronically Scanned Array.

 

AESA stands for Active Electronically Scanned Array, as opposed to PESA, which stands for Passive Electronically Scanned Array.

 

I'll just leave this here because it has lots of good info.

 

Carlo Kopp is a fear mongerer. You have to take everything on that page with large amounts of salt.

Edited September 16, 2016 by sobek

[lmp]

The MiG-21bis with its RP-22 radar, in contrast, uses conical scanning and a twist-cassagrain antenna.

 

AFAIK the RP-22 is a monopulse radar, as opposed to the RP-21 utilized by the earlier versions of the MiG-21 which was a connical scanning radar.

[SkateZilla]

AESA stands for Active Electronically Scanned Array, as opposed to PESA, which stands for Passive Electronically Scanned Array.

 

I Blame Auto Correct..

[red_coreSix]

AFAIK the RP-22 is a monopulse radar, as opposed to the RP-21 utilized by the earlier versions of the MiG-21 which was a connical scanning radar.

 

Yes, it's a monopulse without doppler. It has an MTI filter against ground and cloud clutter though. It still shouldn't be able to track targets close to the ground at all.

 

I also read, there are older fighters with continuous wave Radars and Monopulse antennas. But I can't find any sources, which fighters/ Radars use(d) such technologies and antennas. And I read, some of this older Radars were immune to some (or most) jamming techniques (IIRC, it was the continuous wave), as well.

 

Having a CW radar in an aircraft doesn't make much sense as it doesn't give target range. Some radars are capable of using sub-modes that employ CW for missile guidance.

Continuous wave isn't immune to jamming, in fact it's probably the easiest to jam. All you need is a jammer that injects a false doppler shift into the return and velocity readings will be off.

A FMCW (Frequency modulated continuous wave) radar is much harder to jam as they hop frequency to get target range as well as velocity (e.g. Clam Shell).

[VTJS17_Fire]

Ok, thanks.

[Eihort]

Carlo Kopp is a fear mongerer. You have to take everything on that page with large amounts of salt.

 

Based on what?

[GGTharos]

Based on how he misrepresents things to drive his agenda. That doesn't mean everything is like that - as long as you ignore his 'vs' stuff and realize he always misrepresents missile topics you're good.

[Bacab]

Based on how he misrepresents things to drive his agenda. That doesn't mean everything is like that - as long as you ignore his 'vs' stuff and realize he always misrepresents missile topics you're good.

+1

 

Which technic is used by the MTI of the RP-22 ?

[red_coreSix]

Which technic is used by the MTI of the RP-22 ?

 

Older radars often stored received returns, phase shifted them 180° and integrated them into the returns of the next antenna sweep. Destructive interference will then cancel out stationary targets. I don't know if this is the technique used by the RP-22, but it's very likely.

[Bacab]

Older radars often stored received returns, phase shifted them 180° and integrated them into the returns of the next antenna sweep. Destructive interference will then cancel out stationary targets. I don't know if this is the technique used by the RP-22, but it's very likely.

I know but this is the only other trick I know to do that so I was wondering if an other one existed I didn't know about.

Can something based on contrast could have been used ?

[GGTharos]

What contrast? :)

 

Are you talking about spectral highlighting/analysis? You probably can't really do that with older radars.

[red_coreSix]

I know but this is the only other trick I know to do that so I was wondering if an other one existed I didn't know about.

Can something based on contrast could have been used ?

 

Next thing I can think of would be pulse-pair-processing where the radar will look at changes in the return phase. Moving targets will have alternating phases, stationary won't and will thus be filtered out. But this will only work with newer radar types and probably isn't implemented in the RP-22.

[Bacab]

What contrast? :)

 

Are you talking about spectral highlighting/analysis? You probably can't really do that with older radars.

This is pure speculation as I know nothing about how old radar signal processing was done.

Should the length of the pulse be short enough the target of interest would generate an echo distinct from the ground return. Then it might be possible to keep only the part of the signal containing the first rise in power. As soon as the power decrease again your stop listening and therefore get rid of the ground.