Sidelobe clutter in Pulse ?

[Robin_Hood]

Hi everyone, I hope some people can shed some light on this for me. I was wondering why there seems to be no sidelobe clutter (especially altitude returns) in PULSE SEARCH mode. I have searched but couldn't find anyone mentioning sidelobe clutter except in relation to Pulse Doppler.

I understand that in Pulse Doppler, both main lobe clutter and altitude returns are filtered (MLC filter and Zero-Doppler filter respectively), and that the zero-doppler filter cannot be deactivated. However, it occurs to me that in Pulse Mode, the sidelobes should also be a problem, and shouldn't altitude returns also appear, at a distance roughly equal to the aircraft's current height? A sidelobe pointing at the ground in pulse mode would create a return, wouldn't it?

Is there still some Doppler processing anyway with the zero-doppler filter even in Pulse, or some other way of filtering out aititude returns, or is it simply not implemented? Or am I missing something?

Edited May 2 by Robin_Hood

[Robin_Hood]

Browsing again through Heatblur's manual, I came across this picture of the Pulse Search mode (page 222), where altitude returns are indicated and displayed approximately in the manner that I would expect. I am guessing then that sidelobe clutter in Pulse Search should be a thing, but is just not implemented (yet?).

Edited Wednesday at 09:59 PM by Robin_Hood

[Naquaii]

6 minutes ago, Robin_Hood said:

Browsing again through Heatblur's manual, I came across this picture of the Pulse Search mode (page 222), where altitude returns are indicated and displayed approximately in the manner that I would expect. I am guessing then that sidelobe clutter in Pulse Search should be a thing, but is just not implemented (yet?).null

It's a combination of things. One is that that radar model for pulse in the AWG-9 isn't nearly as advanced as the one developed for the APQ-120 in the F-4E. It's only natural that our focus for the AWG-9 was on the pulse-doppler side of things. With time and luck there might be some back port of the tech for the AWG-9 as well as it would be nice to improve where we can. No promises of any sort though.

That said it's also not a straight comparison. The AWG-9 is a different animal all-together and various different factors (especially the antenna design) combine to mean that some factors, like the altitude return and sidelobes weren't as prevalent as they were in the APQ-120. Still factors but not the same as the APQ-120. So even if fully implemented you should not expect it to be the same as the APQ-120.

[Robin_Hood]

Got it, thanks. I wasn't making any comparison with the APQ-120 though, I was only talking about the AWG-9 (and the above image is from the F-14 manual).

Anyway, the AWG-9 is already pretty fun to fiddle around with!

Edited Wednesday at 10:00 PM by Robin_Hood

[Naquaii]

19 minutes ago, Robin_Hood said:

Got it, thanks. I wasn't making any comparison with the APQ-120 though, I was only talking about the AWG-9 (and the above image is from the F-14 manual).

Anyway, the AWG-9 is already pretty fun to fiddle around with!

 

Yeah, no worries. Was kinda an assumption on my part as there's much talk about the APQ-120 going on atm. Just wanted to make sure people aren't expecting the exact same picture on a different radar like the AWG-9.

[draconus]

On 5/15/2024 at 11:51 PM, Naquaii said:

One is that that radar model for pulse in the AWG-9 isn't nearly as advanced as the one developed for the APQ-120 in the F-4E.

Why? The quality standards changed or you have better info or more performance freedom?