Best Altitudes For Best Ground Radar Mapping ?

[Avio]

Are there any prescribed altitudes that are best for radar ground mapping at various distances from objectives?

I understand there is an optimal "grazing angle" for the radar to best map out the terrain below ahead.

 

[MagicSlave]

Quote from "Be Afraid of the Dark" pdf included in the docs folder: "The best patch maps result from mapping at between 2° and 10° grazing angles, as these provide a good mix of horizontal and vertical target returns."

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[SloppyDog]

NotSo, the Razbam SME, gave these out in the Razbam's Discord:

 

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[Avio]

Thanks for the helpful info, folks.

Based on the table, at 12nm and 900 ft, the graze angle is only 0.7 degree. Isn't that too low to produce any useful image? Also for low altitude ingress one would actually have flown a lot lower, like below 500ft.

From the table, at 15nm and extrapolate to 15,000 ft would give about 10 degrees angle, at the edge of the 2 to 10 degrees recommended. Most initial/final radar mapping probably useful when further off, before dropping to ingress at low altitude to target.

Would be great if someone could furnish some figures one may use, like at what minimum distance should one drop to low altitude ingress to target for the eventual pop-up attack.

 

[MagicSlave]

Thanks for the helpful info, folks.
Based on the table, at 12nm and 900 ft, the graze angle is only 0.7 degree. Isn't that too low to produce any useful image? Also for low altitude ingress one would actually have flown a lot lower, like below 500ft.
From the table, at 15nm and extrapolate to 15,000 ft would give about 10 degrees angle, at the edge of the 2 to 10 degrees recommended. Most initial/final radar mapping probably useful when further off, before dropping to ingress at low altitude to target.
Would be great if someone could furnish some figures one may use, like at what minimum distance should one drop to low altitude ingress to target for the eventual pop-up attack.
 

Well, "Be Afraid of the Dark" is not official documentation, so there may be mistakes or simplifications. I would place my trust on the materials provided by an SME (Notso).

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[SloppyDog]

14 hours ago, Avio said:

Thanks for the helpful info, folks.

Based on the table, at 12nm and 900 ft, the graze angle is only 0.7 degree. Isn't that too low to produce any useful image? Also for low altitude ingress one would actually have flown a lot lower, like below 500ft.

From the table, at 15nm and extrapolate to 15,000 ft would give about 10 degrees angle, at the edge of the 2 to 10 degrees recommended. Most initial/final radar mapping probably useful when further off, before dropping to ingress at low altitude to target

 

It is lost on the mists of Discord, but NotSo said that they usually do pop-ups along the route to make maps. They do one usually at 10 nm from the target, then go down low, the radar is given to the pilot (A/A) and then on the WSO is looking through the TPOD. My speculation is that these pop-ups would be made in some points that the enemy would have low radar coverage, or little to none time to react. 

Of course, NotSo always says that "good target study and planning are a integral part of the life of a Strike Eagle crew". What I interpret from that is when done in real life, they have many information that they take in account when planning a strike. It is not like we DCS pilots who jump in an Instant Action mission and try to do the best we can.

14 hours ago, Avio said:

Would be great if someone could furnish some figures one may use, like at what minimum distance should one drop to low altitude ingress to target for the eventual pop-up attack.

 

I know it may sound like I'm some kind of NotSo's fanboy, but the fact he is the real deal, being a real life WSO. He is very active in Rambam's Discord and his videos in Razbam's YouTube have been very helpful.

Also, he posts in his own channel lots of great stuff, sometimes answering people's questions or showing procedures for attack runs, like this one:

 

Edited August 23, 2023 by SloppyDog

[Avio]

The table shows various altitudes that are quite high, when most low ingressing probably should be like a couple of hundreds feet to be effective. Also, at very low grazing angles I'm not sure how effective is the radar mapping given that there probably would be quite some tall radar shadows getting in the way.

Normally I try to get a good radar patch out from about 15 nm and beyond, and at 15000 ft or higher, and then dive down to low ingress of 200 ft or so. Larger ground objects can be easily mapped from much further away, but with precision satellite pinpointing coordinates for targets, the radar becomes less needed. In any case, pop-up technique seems more useful when dealing with shorter range and/or potential unknown threats, as longer range threats would mean trying to patch map from higher altitudes when only 15 nm or so away wouldn't be quite as possible.

Any other helpful advice to this?

 

[Mav87th]

From 10pct's great interviews with fx. "Junior" the tactics for a low level ingress is described as a hard braketurn to 45deg off target at between 20 and 10nm to target THEN you would climb to an altitude that gives you the right graze angle. You take the Map image - freeze the image and get down low again and turn towards the target. Cue the TPOD to the designated target and then use the TPOD for the rest of the targeting. WSO was then not on the A-G radar anymore from that point.

 

That was my understanding of Juniors explanation, that maybe wrong, but it does make sense. There might also be other (more likely then not) methods for utilizing the A-G radars HRM.

[Avio]

Yet I also read somewhere that it may be a series of pop-ups, with the earlier ones to build up the general big picture, and the final for refined targeting.

Sure is busy time on the final ingress, especially with only one pilot and no WSO.

 

[SloppyDog]

10 hours ago, Avio said:

The table shows various altitudes that are quite high, when most low ingressing probably should be like a couple of hundreds feet to be effective. Also, at very low grazing angles I'm not sure how effective is the radar mapping given that there probably would be quite some tall radar shadows getting in the way.

Normally I try to get a good radar patch out from about 15 nm and beyond, and at 15000 ft or higher, and then dive down to low ingress of 200 ft or so. Larger ground objects can be easily mapped from much further away, but with precision satellite pinpointing coordinates for targets, the radar becomes less needed. In any case, pop-up technique seems more useful when dealing with shorter range and/or potential unknown threats, as longer range threats would mean trying to patch map from higher altitudes when only 15 nm or so away wouldn't be quite as possible.

Any other helpful advice to this?

 

I don't believe you should take the grazing angle table as a rule "written in stone". From interviews in various YouTube channels the former WSOs say they took maps from 40nm out to the target. Of course, they've already knew what they were going to hit, and taking maps was a way to refine the targeting solution. I haven't tested it in DCS, but in the good ole Jane's F-15 you could take a map from 40 nm at 5,000 feet AGL. Then go EMIS (Emission Silent), meaning no radar, no ECM, no radio transmissions, getting low, closer to the target another map, low again, and as @Mav87th said, the WSO would hand off the radar to the pilot and would Target using the TPOD from that point on. Of course, what I'm describing here is a contested airspace case like in the first Cold War and the opening days of Desert Storm. In these scenarios I would never be at 15,000 ft prior to the target, unless leaving a tanker track on the way to Fence In. From that point one it would be low and fast, pop-up, low/fast, pop-up, attack, low/fast, get out.

Showing below is an attack profile of an F-111 using a GBU-15. It is interesting to note the last navigation update before IP, the attack run with terminal guidance by TPOD, loft, egress.