Ground Mapping Radar

[KlarSnow]

Thats incorrect, if its GMTI is using doppler it can detect moving targets no matter the size (assuming not smaller than a vehicle) at just about any range, if it has doppler shift and a return it should show up, just like an air target.

 

Think it removes the doppler notch filter completely or drops it down to ~2 knots and then caps it at around 100, anything showing a velocity between 2 and 100 knots should show up as a target if its using doppler as a discriminator. Should look somewhat like a clean air to air display.

 

Detecting a target using doppler is separate from the radars resolution using SAR or DBS, and is not limited by the resolution of the radar, only by the size of the doppler return and the RCS of the target. You won't be able to take a SAR image of the mover or do anything other than (like an air target) have a track file that your radar is updating.

[Santi871]

Thats incorrect, if its GMTI is using doppler it can detect moving targets no matter the size (assuming not smaller than a vehicle) at just about any range, if it has doppler shift and a return it should show up, just like an air target.

 

Think it removes the doppler notch filter completely or drops it down to ~2 knots and then caps it at around 100, anything showing a velocity between 2 and 100 knots should show up as a target if its using doppler as a discriminator. Should look somewhat like a clean air to air display.

 

Detecting a target using doppler is separate from the radars resolution using SAR or DBS, and is not limited by the resolution of the radar, only by the size of the doppler return and the RCS of the target. You won't be able to take a SAR image of the mover or do anything other than (like an air target) have a track file that your radar is updating.

 

Yeah, it's possible that limitation is only for fixed target track. I will have a read again later.

 

I assume if GMTI uses doppler many vehicles moving close together at the same speed could show up as one target though, much like several aircraft in formation in RWS.

Edited June 30, 2019 by Santi871

[backspace340]

Thats incorrect, if its GMTI is using doppler it can detect moving targets no matter the size (assuming not smaller than a vehicle) at just about any range, if it has doppler shift and a return it should show up, just like an air target.

 

Think it removes the doppler notch filter completely or drops it down to ~2 knots and then caps it at around 100, anything showing a velocity between 2 and 100 knots should show up as a target if its using doppler as a discriminator. Should look somewhat like a clean air to air display.

 

Detecting a target using doppler is separate from the radars resolution using SAR or DBS, and is not limited by the resolution of the radar, only by the size of the doppler return and the RCS of the target. You won't be able to take a SAR image of the mover or do anything other than (like an air target) have a track file that your radar is updating.

 

Is there normally a maximum number of GMT tracks that can be displayed? Just wondering what would happen if you used it near a busy highway - would you get thousands of hits being displayed?

[Fri13]

Thats incorrect, if its GMTI is using doppler it can detect moving targets no matter the size (assuming not smaller than a vehicle) at just about any range, if it has doppler shift and a return it should show up, just like an air target.

 

Think it removes the doppler notch filter completely or drops it down to ~2 knots and then caps it at around 100, anything showing a velocity between 2 and 100 knots should show up as a target if its using doppler as a discriminator. Should look somewhat like a clean air to air display.

 

Detecting a target using doppler is separate from the radars resolution using SAR or DBS, and is not limited by the resolution of the radar, only by the size of the doppler return and the RCS of the target. You won't be able to take a SAR image of the mover or do anything other than (like an air target) have a track file that your radar is updating.

 

That I heard from former hornet pilot in the end of 90's.

 

And similarity is from the wiki:

 

Moving target indication (MTI) is a mode of operation of a radar to discriminate a target against the clutter.[1] It describes a variety of techniques used to find moving objects, like an aircraft, and filter out unmoving ones, like hills or trees. It contrasts with the modern stationary target indication (STI) technique, which uses details of the signal to directly determine the mechanical properties of the reflecting objects and thereby find targets whether they are moving or not.

 

Early MTI systems generally used an acoustic delay line to store a single pulse of the received signal for exactly the time between broadcasts (the pulse repetition frequency). This stored pulse will be sent to the display along with the next received pulse. The result was that the signal from any objects that did not move mixed with the stored signal and became muted out. Only signals that changed, because they moved, remained on the display. These were subject to a wide variety of noise effects that made them useful only for strong signals, generally for aircraft or ship detection.

 

https://en.m.wikipedia.org/wiki/Moving_target_indication

 

So in simple terms, scan the ground and memorize the signal. Compare the new scan to previous and what is changed means there is a moving Target.

 

Not so that scanning finds a moving Target by its speed.

 

The most modern systems can do such thing, but shouldn't be our hornet (as the one I refer).

 

And doesn't that sound similar as well to one comment little above from ex pilots telling it was useful mainly for anti ship missions?

https://forums.eagle.ru/showpost.php?p=3965006&postcount=18

[backspace340]

KlarSnow is probably the only person in this thread so far who's actually used GMTI in a real aircraft (he's a Strike Eagle WSO IIRC).

[Beamscanner]

That I heard from former hornet pilot in the end of 90's.

 

And similarity is from the wiki:

 

 

 

https://en.m.wikipedia.org/wiki/Moving_target_indication

 

So in simple terms, scan the ground and memorize the signal. Compare the new scan to previous and what is changed means there is a moving Target.

 

Not so that scanning finds a moving Target by its speed.

 

The most modern systems can do such thing, but shouldn't be our hornet (as the one I refer).

 

 

You're wrong on all accounts.

 

The F/A-18C can do very fine doppler processing. Including in GMTI, GMTT, SEA, DBS, SAR, PVU, etc..

 

Legacy MTI like you referenced in none doppler radars used the beat frequency of a targets consistent phase shift to distinguish moving from none moving targets. Older Pulse only radars like the MIG-23's Highlark use this technique. However, at no time can old school "MTI" resolve the actual doppler shift (velocity) of any target. All it knows is that something is moving relative to its transmitted signal.

 

Most air to air modes, DBS, SAR, Scan RAID, etc need to resolve the exact doppler of a target.

 

So yes, the Hornet does doppler processing (real Doppler, not old school MTI) in almost all modes. RBGM being one that it probably doesn't.

 

And doesn't that sound similar as well to one comment little above from ex pilots telling it was useful mainly for anti ship missions?

https://forums.eagle.ru/showpost.php?p=3965006&postcount=18

 

Thats a nice telephone game there. But to that point, just because something isnt often used doesn't mean it doesn't work.

Edited June 30, 2019 by Beamscanner

[Fri13]

KlarSnow is probably the only person in this thread so far who's actually used GMTI in a real aircraft (he's a Strike Eagle WSO IIRC).

 

I am only telling what the F-18C pilot told me, flying the exact same one that we have in DCS.

[toilet2000]

I am only telling what the F-18C pilot told me, flying the exact same one that we have in DCS.

 

When your targets are insurgents hiding in villages with a high collateral damage chance, for sure you’re not gonna rely on radar imagery. Same for CAS, where the JTAC is basically guiding you in. In those cases, an AG radar seems useless.

 

Given that’s the battlefield conditions the exact same Hornet we fly flew in, for sure pilots accounts will describe the AG radar as almost never used.

 

But in a all-out war with night/adverse weather strikes and such, having an AG radar is a must, just like it was in Desert Storm.

[QuiGon]

Exactly. It's useless for asymetric COIN operations in environments like Afghanistan, but it is very usefull in symetric and high intensity conflicts, especially in desert environments, to locate stuff like tanks and SAM sites.

It is absolutly necessary for naval warfare to detect ships on the ocean.

[sk000tch]

Exactly. It's useless for asymetric COIN operations in environments like Afghanistan, but it is very usefull in symetric and high intensity conflicts, especially in desert environments, to locate stuff like tanks and SAM sites.

It is absolutly necessary for naval warfare to detect ships on the ocean.

 

Not being critical of you specifically but what real pilots do is of no real consequence. DCS is a different tactical environment, we either fly SP with scripted ai wingmen, or online with limited coordination, no mission planning, no intelligence or surveillance. For real-time we basically get awacs, no ATARS for ground targets (our aegis don’t even contribute).

 

No RL Hornet driver is going to fly solo, build a SAR image of a target area, ID targets of opportunity and salvo off eight stand off weapons. We necessarily are more self sufficient in locating, identifying, and firing on targets. So while ground moving may not be useful in a real theater loaded with civilians, for us, a tpod slaved to GMT might be pretty damn useful.

 

Terrain avoidance is another good example. The low altitude flight we routinely do is completely unrealistic, so where TA may never be used irl it might be useful for the missions we fly.

[QuiGon]

Not being critical of you specifically but what real pilots do is of no real consequence. DCS is a different tactical environment, we either fly SP with scripted ai wingmen, or online with limited coordination, no mission planning, no intelligence or surveillance. For real-time we basically get awacs, no ATARS for ground targets (our aegis don’t even contribute).

 

No RL Hornet driver is going to fly solo, build a SAR image of a target area, ID targets of opportunity and salvo off eight stand off weapons. We necessarily are more self sufficient in locating, identifying, and firing on targets. So while ground moving may not be useful in a real theater loaded with civilians, for us, a tpod slaved to GMT might be pretty damn useful.

 

Terrain avoidance is another good example. The low altitude flight we routinely do is completely unrealistic, so where TA may never be used irl it might be useful for the missions we fly.

Well, seems like you do completely different flying in DCS than I do.

[Preendog]

When the F10 map and labels are not available, gotta find the vehicle icons somehow. AG radar and tpod sounds exciting.

 

Someday we will be able to orbit in the middle of the map and just toss sows and poons at blips in all directions. The smackdown will be so epic the Bug will be renamed the Sharknado.

[Fri13]

When your targets are insurgents hiding in villages with a high collateral damage chance, for sure you’re not gonna rely on radar imagery. Same for CAS, where the JTAC is basically guiding you in. In those cases, an AG radar seems useless.

 

There are two kinds of environments that I compare things about and they are:

 

1. European (north) landscape, lots of forests, tall trees, narrow roads through forests, lakes, fields with little to none altitude changes etc.
    
   
2. Middle-East landscape, deserts, lots of open areas and rocky landscape. Mountains and lots of small canyons etc.
   

 

You can use almost any radar to spot a vehicle on the desert as long your radar can identify a flat reflection. But if you dig that vehicle to sand and you cover with with nets, you can have some concealment but still a advanced radar can see through the net.

 

In the european terrain, you are not having just nets, you have all the foliage covering the vehicles. You have lots of trees and bushes etc. Even the advanced A-G radars that can see through foliage and even couple meters under surface has difficulties to detect a correctly concealed vehicle because all its shapes are broken with trees etc. Even your FLIR can't see or detect a such vehicle in war condition unless it has been running for hours and crew has failed its concealment (those are checked by the FLIR in the platoons that vehicles are undetectable by FLIR, you don't even have a single soldier there to lit a cigarette or work without a masked uniform and faces, you will even see a rabbit or squirrel before you can see in FLIR a correctly concealed infantry, even less visually or by the radars).

 

 

Given that’s the battlefield conditions the exact same Hornet we fly flew in, for sure pilots accounts will describe the AG radar as almost never used.

 

But in a all-out war with night/adverse weather strikes and such, having an AG radar is a must, just like it was in Desert Storm.

 

In a All-Out war you use every method you can have, and A-G is not a tool that just makes you to see where enemy is in most situations. It depends that against who you are fighting for, not that you are fighting for.

 

As the opposite side can be there flying with that exact same Hornet, with at exact A-G features, with knowledge how to hide from it. With all the experience and methods to check their own troops that the enemy who is using the same equipment or based to those (new generation etc), can't use those methods against you to find them.

 

We (DCS) lacks all ground military branches. We can simulate a AWACS or Air Tanker etc, even make a believable carrier fleet, but not the ground branches or their strategies and tactics. Hopefully that changes in the upcoming RTS elements and everything they can add is just huge improvement.