AN/APG-77 detection range

ferry265 · by **ferry265** » 29 Mar 2016, 21:12

Hello. I did read sometimes that Raptor´s radar AN/APG-77 can detect 1m2 on 400km away. Is that true ?
Thanks for answer. :wink:

str · by **str** » 29 Mar 2016, 21:54

Sure, in search or look-down modes. But there's also the look-through mode, which peers through the center of the earth to tell you what's flying around on the opposite side of the planet.

/s

mixelflick · by **mixelflick** » 30 Mar 2016, 12:34

ferry265 wrote:Hello. I did read sometimes that Raptor´s radar AN/APG-77 can detect 1m2 on 400km away. Is that true ?
Thanks for answer.

Make that 407km away.

Revised and updated DOD specs, for PAK FA program management to shoot for...

ferry265 · by **ferry265** » 30 Mar 2016, 14:10

Thank you very much to both :wink:

And can F-22 detect enemy stealth jets on longer distance with AN/ALR-94 ? Teach me

Thanks!

charlielima223 · by **charlielima223** » 30 Mar 2016, 20:58

ferry265 wrote:Thank you very much to both
And can F-22 detect enemy stealth jets on longer distance with AN/ALR-94 ? Teach me
Thanks!

First off welcome the board. Also there has been plenty of discussion about topics you are inquiring. You can browse around or use the search function to find your answers. With some you wont get a definitive yes/no.

ferry265 · by **ferry265** » 30 Mar 2016, 21:21

Ok. Thanks for tips

eloise · by **eloise** » 30 Mar 2016, 22:45

ferry265 wrote:Thank you very much to both
And can F-22 detect enemy stealth jets on longer distance with AN/ALR-94 ? Teach me
Thanks!

Have a look at garry blog
viewtopic.php?f=22&t=29022

popcorn · by **popcorn** » 07 Aug 2016, 10:22

Re APG 77 and APG 81 is there any technical reason why you couldn't have a mix of T/R modules to provide a multi-band radar capability ie. not be limited exclusively to X-band. If possible, this could make it a more versatile jamming patform.

SpudmanWP · by **SpudmanWP** » 07 Aug 2016, 18:18

AESA radar modules have to be physically nest to one another in order to be able to steer, There is also a set number of modules needed in order to steer to the to the extremes of the sides.

Given this, you can't simply add a few along the edge. You would need large blocks of each.

The holy grail of AESA radars would be to make the module itself multiband.

popcorn · by **popcorn** » 07 Aug 2016, 23:44

So if I understand it right, they could block off a portion of the array and populate it with T/R modules of a difcerent frequency. Short of achieving the holy grail of a multi-band T/R module, perhaps this could be an acceptable compromise? All speculative...

SpudmanWP · by **SpudmanWP** » 08 Aug 2016, 03:53

While you would get multiple freqs, you would also have a lower range with each freq.

For the best range, you need them all transmitting at the same freq.

popcorn · by **popcorn** » 08 Aug 2016, 04:33

SpudmanWP wrote:While you would get multiple freqs, you would also have a lower range with each freq.

For the best range, you need them all transmitting at the same freq.

I agree. I was thinking there might be a sweet spot where they could achieve an acceptable level of performance in X-Band using a reduced number of T/Rs while having the balance in T/Rs of a different frequency. Give up a bit on max range but gain in oher areas eg. being able to jam in more frequencies.

hornetfinn · by **hornetfinn** » 08 Aug 2016, 07:04

As with all the good ideas these days, somebody has thought about it long time ago. There are ways to do what you describe and there are patents which describe how it can be done.

Some patents:
https://www.google.com/patents/US6891514
https://www.google.com/patents/US6239762
http://www.google.ca/patents/US7830301

Basically, you can stack antenna arrays together and each would work in different frequency. As antenna arrays get thinner and lighter (especially with future GaN technology), it might be very possible to stack antenna arrays in such a way that the whole radar/jammer/EW/comms system covers say UHF band to Ka band or something similar. I'd say we can stop talking about radars (Radio Detection and Ranging) system and make up a new name like "RF system" as these systems are now having capabilities way beyond radar functionality. Another way is what SpudmanWP described, having wideband modules. That has the advantage of having lower volume and weight and simpler design and construction (and thus costs). Having one array with different sized modules would not work very well as that would affect performance in each frequency. IMO, in the future we will see combination of both stacked arrays and multiband modules. Very likely 6th gen fighters in the future will have some insane RF capabilities that take F-35 RF systems to totally another level.

There are definitely a lot of difficult challenges trying to combine different frequencies to one system and this is probably why complete AN/SPY-3 system has two different and separate antenna arrays for X-band and S-band operations. NGJ also seems to have two separate arrays for different bands.

popcorn · by **popcorn** » 08 Aug 2016, 10:46

Thanks hornetfinn, sounds rrasonable.

kapcapkap · by **kapcapkap** » 20 Apr 2017, 22:43

mixelflick wrote:
ferry265 wrote:Hello. I did read sometimes that Raptor´s radar AN/APG-77 can detect 1m2 on 400km away. Is that true ?
Thanks for answer.

Make that 407km away.

Revised and updated DOD specs, for PAK FA program management to shoot for...

Can you please provide a link, or other means of finding this source, for this information; it would be a very useful source to cite. Thank you.