Question about AG radar scan limit in elevation

[Akiazusa]

I've just picked up the Hornet recently and I'm really enjoying it.

But I noticed that when the radar is in AG scan mode. It can still mapping ground normally while the aircraft is in a 80+° vertical climb ,and it can still get returns normally from up to 160+nm when you are flying at tree level and pointing the antenna all the way down(if there is no mountain ahead of course).

Are these normal for the Hornet's radar?

Just curious. Thanks for any help in advance.

Edited June 1, 2022 by Akiazusa

[Hulkbust44]

I've just picked up the Hornet recently and I'm really enjoying it.
But I noticed that when the radar is in AG scan mode. It can still mapping ground normally while the aircraft is in a 80+° vertical climb ,and it can still get returns normally from up to 160+nm when you are flying at tree level and pointing the antenna all the way down(if there is no mountain ahead of course).
Are these normal for the Hornet's radar?
Just curious. Thanks for any help in advance.

Yes, because (@BIGNEWY correct me if I'm wrong) DCS dosen't actually model the radar, it's just a filtered version of what the map would look like with azimuth limits for the display.

Of course you would have those LOS limits IRL. Now in at 80° the radar can still face down enough to map at a distance, but I've seen it track the ground below me in a pure vertical climb.

[Akiazusa]

41 minutes ago, Hulkbust44 said:

 

 

Yes, because (@BIGNEWY correct me if I'm wrong) DCS dosen't actually model the radar, it's just a filtered version of what the map would look like with azimuth limits for the display.

Of course you would have those LOS limits IRL. Now in at 80° the radar can still face down enough to map at a distance, but I've seen it track the ground below me in a pure vertical climb.

Thanks,if that's not actually modeled, then at least it makes a lot more sense to me.

As I also play the Mirage, I think this limit it's modeled correctly on that aircraft.  Anyway I guess let's just hope it will become better as time goes by.

[NineLine]

2 hours ago, Hulkbust44 said:

 

 

Yes, because (@BIGNEWY correct me if I'm wrong) DCS dosen't actually model the radar, it's just a filtered version of what the map would look like with azimuth limits for the display.

Of course you would have those LOS limits IRL. Now in at 80° the radar can still face down enough to map at a distance, but I've seen it track the ground below me in a pure vertical climb.

 

Sorry, this is not correct, the issue is the current DCS terrain is not a true round earth.

[Akiazusa]

Sorry,but I'm still a little confused.

I drew some pictures to better explain my concern.

[Akiazusa]

I did some further testing,and it seems that the problem is that in AG mode,every scan covers the whole -60° to 60° (or something approximate) in elevation around where antenna is pointing ,instead of covering just a few degrees in elevation like in AA mode.

 

And also it seems that the radar physical limitation is always based on a level flying aircraft so the radar antenna will always points to where Radar Elevation Control is commanding it to without checking aircraft attitude first.

(In a vertical climb,the radar can map the terrain direct below the aircraft.)

Probably this is the reason?

 

Edited June 9, 2022 by Akiazusa

[SeaBass80]

As ED is always really focused on getting the subsystem modeling as correct as can be based on public data, I was also wondering about the roadmap for the ground mapping (GM) radar modes. We have essentially the same problem in the F-16.

Based on public data and physical intuition, the real-beam-mode "RBM" ground scan use a standard radar beam emitting from the radar dish antenna that (for the F-16) has a cone angles of ~4°. This angle defines the azimuth resolution of the radar image (in F-16 improved to ~1° by software magic "EDM" enhanced mode). In the vertical plane, the 4° defines the scannable patch of ground, while the resolution in this direction comes from measuring pulse echo delays and is thus much higher.

As the OP noticed, there are a few deficiencies in the depiction of GM radar modes at the moment, both in the F-18 and the F-16:

• The vertical plane beam size after a single scan (1-bar) for the radar dish extends from right below the aircraft to the horizon... this is impossible. It should be 4° in the vertical plane. This is a severe limitation in real life when flying at large altitudes: the radar will still map the +-60° in azimuth, buth only a tiny slice of the terrain ahead (vertical scan plane or distance direction on the radar map).
• The antenna height orientation is not referenced to the airplane. A plane going vertically up cannot map the ground with a front-facing radar.

Both of these issues should be straightforward to correct as they don't require recoding of the actual radar-mapping code. The "only" thing to do is to correctly implement the real-world pointing and scanning limitations. This is independent of how the actual radar map is calculated (ray tracing or some logic based on the 2D map).

There is another limitation that I haven't seen being discussed anywhere:

• There are no radar returns whatsoever from above the horizon line. I found references for the F-16 of pilots being instructed to use the narrowest sideways scan pattern with the antenna pointed into the sky straight ahead of the aircraft in order to check for weather conditions ahead. Seeing rain on the radar would be the next step in realism.

This last thing might indeed require more work on the radar code, though.

Everyone focuses on the A-A radar implementation for obvious reasons, but I would love to see ED getting back to improving the realism on this fundamental part of technology. I would say these are lower hanging fruits than dealing with dropped radar lock issues and any of the hundreds of posts complaining about radar lock range and stuff.

Edited June 10, 2022 by SeaBass80

[DummyCatz]

@BIGNEWY Hi, could you possibly take a look at the above comments. Basically two bugs:

1. 1-bar scan beam size not realistic

2. radar beam exceeding antenna tilt limit

The simulation of a true round earth is not related.