BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 15 Jul 2016, 16:08
by spazsinbad
BAE Systems Inches Out In Public On Electronic Warfare
15 Jul 2016 Colin Clark

"FARNBOROUGH: For much of the last few years when one thought of electronic warfare, one tended to think of Raytheon. After all, they’re building the Next Generation Jammer, right?

BAE Systems would like to change that and is beginning to take a guarded but more public stance. For years, Air Force officials have declined to discuss the electronic warfare and cyber capabilities of the F-35 Joint Strike Fighter for example, which BAE Systems builds.

Then the head of Air Combat Command, Gen. Hawk Carlisle, began to publicly mention these capabilities at the Royal International Air Tattoo at RAF Fairford last week. He said the F-35’s EW capabilities are “an order of magnitude better than anything we’ve had in the past.” That, I can tell you, put a smile on the face of at least two BAE employees.

Until now, we’ve had little independent insight from the military on the actual performance of the F-35’s EW and cyber capabilities. I know from speaking with a range of Air Force and industry officials over the last two years that a key part of the F-35’s effectiveness derives from the fact it was designed from the get-go to launch both cyber and EW attacks on enemy air defenses, especially the most advanced Russian missile systems such as the S-400. Anything that emits, such as radios, radar and other sources, can be attacked.

Here are two marketing statements about the systems by, respectively, Lockheed Martin and BAE:
“Advanced electronic warfare capabilities enable the F-35 to locate and track enemy forces, jam radio frequencies and disrupt attacks with unparalleled precision. All three variants of the F-35 carry active, electronically scanned array (AESA) radars with sophisticated electronic attack capabilities, including false targets, network attack, advanced jamming and algorithm-packed data streams. This system allows the F-35 to reach well-defended targets and suppress enemy radars that threaten the F-35. In addition, the ASQ-239 system provides fully integrated radar warning, targeting support, and self-protection, to detect and defeat surface and airborne threats.

“While F-35 is capable of stand-off jamming for other aircraft — providing 10 times the effective radiated power of any legacy fighter — F-35s can also operate in closer proximity to the threat (‘stand-in’) to provide jamming power many multiples that of any legacy fighter.”

From BAE: “Always active, AN/ASQ-239 provides all-aspect, broadband protection, allowing the F-35 to reach well-defended targets and suppress enemy radars. The system stands alone in its ability to operate in signal-dense environments, providing the aircraft with radio-frequency and infrared countermeasures, and rapid response capabilities.”


But as you can see from the graphic above, first-ranked EW is not something new for BAE Systems. The F-22 and B-2 both rely on BAE capabilities. What you will hear very little about is the convergence of EW and cyber in the F-35 thanks to the Northrop Grumman-built AESA radar and the plane’s huge quantities of software, much of which is written by BAE Systems employees. In addition to the EW capabilities, BAE writes software for the fuel management system and other unspecified operating systems.

We look forward to hearing more details from BAE." [Yeah Right]

Graphic/PHOTO: http://breakingdefense.com/wp-content/u ... 24x576.jpg

Source: http://breakingdefense.com/2016/07/bae- ... c-warfare/

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 26 Jul 2016, 09:39
by citanon
Now out with a video:



The YF-23 lives!!!

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 16 Oct 2016, 02:18
by spazsinbad
Electronic warfare for the F-35
Published on Sep 15, 2016 baesystemsinc

"BAE Systems’ AN/ASQ 239 electronic warfare system for the F-35 is a fully integrated digital solution that provides offensive and defensive EW, radar warning, targeting support, and self-protection."


Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 00:36
by neptune
Question:
....if the ASQ-239 system; "All three variants of the F-35 carry active, electronically scanned array (AESA) radars with sophisticated electronic attack capabilities, including false targets, network attack, advanced jamming and algorithm-packed data streams. This system allows the F-35 to reach well-defended targets and suppress enemy radars that threaten the F-35. In addition, the ASQ-239 system provides fully integrated radar warning, targeting support, and self-protection, to detect and defeat surface and airborne threats."
...then the system would appear to be becoming complete for 3F (having met the scope of design)..

..that assumed, then the upgrading of the two-seater legacy a/c F-15/16/18 are adding AESA radars, that "could" be coupled to a new ASQ-239/ mission system for the GIB (backseater) to manage without bothering the GIF (pilot) with the new systems capabilities...(plane can still fly but with more SA!)...
...sensors (receivers) could be added with little concern for the LO issue with the F-35s and suddenly a fleet of EA/EW a/c using an established system could be fielded with only engineering and parts costs (with little software development)...

... not to discourage the development of the NGJ but.....maybe it (or the algorithms) can integrated into the legacy a/c via ASQ-239???....lot of sensing in an AESA and a lot of mission specific jamming power for a single a/c....IMHO
..and then there is that MADL/ comm. thingee and these missile/ bomb mules can become extended networking "eyes and ears"
:wink:

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 00:44
by SpudmanWP
You need a VLO airframe in order for the -239 to be effective enough to do the job. Remember that the radar (ie the only jammer element) only covers the front aspect.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 01:46
by wrightwing
SpudmanWP wrote:You need a VLO airframe in order for the -239 to be effective enough to do the job. Remember that the radar (ie the only jammer element) only covers the front aspect.

It sounds like the system is a broadband jammer, while the APG-81 focuses on X band fire control radars.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 01:53
by quicksilver
SpudmanWP wrote:You need a VLO airframe in order for the -239 to be effective enough to do the job.


Hmmm...this statement (from the quotes above) would appear to contradict that idea.

“...F-35 is capable of stand-off jamming for other aircraft — providing 10 times the effective radiated power of any legacy fighter — F-35s can also operate in closer proximity to the threat (‘stand-in’) to provide jamming power many multiples that of any legacy fighter.”

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 02:07
by SpudmanWP
The radar can provide stanoff x-band jamming using the APG-81 as the radiating element. However, it's only in the aspect that is covered by the AESA antenna. It can achieve this 10x efficiency through two methods, large radiating power (ie large antenna) and being able to focus the radiated power over long distances (ie AESA antenna).

Both of those are limited to the forward sector of the F-35 and no, the -239 does not radiate any other kind of jamming signal other than the APG-81 based signals.

In case I was not clear enough, I was trying to say that an F-16 with an APG-81 & a -239 could not penetrate & survive in the same missions that the F-35 can. The VLO airframe is too central to its survival.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 03:02
by popcorn
SpudmanWP wrote:Both of those are limited to the forward sector of the F-35 and no, the -239 does not radiate any other kind of jamming signal other than the APG-81 based signals.


I'm nitpicking and assume that the ALE 70 has jamming capability but limited to defending it's host F-35.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 03:22
by garrya
SpudmanWP wrote:Both of those are limited to the forward sector of the F-35 and no, the -239 does not radiate any other kind of jamming signal other than the APG-81 based signals..

AFAIK , ASQ-239 can jam adversary without using APG-81 aperture , and F-35 carry towed decoy too
Image

SpudmanWP wrote:In case I was not clear enough, I was trying to say that an F-16 with an APG-81 & a -239 could not penetrate & survive in the same missions that the F-35 can. The VLO airframe is too central to its survival.

This i agree , the synergy between jamming and low radar cross section is unquestionable.
Image

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 05:09
by SpudmanWP
On the "Simultaneous jamming without interfering with radar"... it's because of the radar's AESA functionality that it can quickly switch back and forth without loosing capability.

Where did that pic come from, brochure or article?


-----------Upon further investigation-------

It looks like the USN did put a contract out in April 2014 that has caused some confusion.

BAE Systems Electronic Solutions, Nashua, N.H., is being awarded a $47,352,248 indefinite-delivery/indefinite-quantity delivery order contract for the manufacture of the transmitter countermeasures T-1687A/ALE-70 (V) in support of the Joint Strike Fighter program. Work will be performed at Nashua, N.H., and work is expected to be completed by April 2017. Fiscal 2014 procurement of ammunition Navy and Marine Corps, and fiscal 2012 Air Force aircraft funding in the amount of $14,314,816 will be obligated at the time of award. The Air Force funds in the amount of $6,308,224 will expire at the end of the current fiscal year. This contract was not competitively procured in accordance with 10 U.S.C. 2304 (c)(l). The NAVSUP Weapon Systems Support, Mechanicsburg, Pa., is the contracting activity (N00104-14-D-K054).

http://archive.defense.gov/Contracts/Co ... actID=5255

These two Budget docs provide a lot of clues... still digging

http://www.dtic.mil/procurement/Y2017/N ... B_2017.pdf
http://www.dtic.mil/procurement/Y2017/A ... B_2017.pdf

I was wrong about the ALE-70.... the program is buying 318 of them in FY2017 and has been buying them for yeays (search the budget docs for "ALE-70" and you will see them going back to 2014.

DESCRIPTION:
The ALE-70 Towed Decoy is a countermeasures dispenser system designed to fit into the F-35 Joint Strike Fighter (JSF) aircraft. The ALE-70 provides aircraft self-protection against radar guided missiles.
Funds procure all system components: decoys, canisters, and explosive cartridges to deploy the decoys.


F-35 COUNTERMEASURES: Includes all unique countermeasures that provide self-protection for the Joint Strike Fighter (JSF) aircraft, specifically ALE-70, MJU-68, MJU-69 and CCU-168. In addition to F-35
unique countermeasures, MJU-61 and MJU-64 are also used for F-35 self-protection.


ALE-70 = Towed Decoy ($50k each)
MJU-68/69 = Flares http://www.chemring.co.uk/~/media/Files ... ct2014.pdf
CCU-168 = Impulse cartridge for the flares https://govtribe.com/project/13-pn-8385 ... e/activity
MJU-61/64 = also flares (4 differenc kinds?)

Absence of chaff info is odd....

This tidbit from the FY2017 budget (looks like the ALE-70 is in Block 2B/3i already:
(14) ALE-70 FY 2015 quantities increased from PB 2016 to accommodate F-35B IOC. FY 2017 quantity change from PB 2016 due to revised F-35B delivery schedule.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 07:54
by garrya
SpudmanWP wrote:On the "Simultaneous jamming without interfering with radar"... it's because of the radar's AESA functionality that it can quickly switch back and forth without loosing capability.

Technically speaking if you do that , there will be lost on capabilities namely fewer pulse used for detection purpose so shorter detection range. Moreover, i just dont see why ASQ-239 doesn't have their own transmitting aperture, afterall APG-81 is not produced by MBDA but by Northrop Grumman , so i would think they would rather rely on their own electronic parts

SpudmanWP wrote:Where did that pic come from, brochure or article?

Brochure , just search ASQ-239 and you will see
SpudmanWP wrote:ALE-70 = Towed Decoy ($50k each)

This about twice as expensive as ALE-50 but half as expensive as ALE-55 ? odd

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 08:03
by SpudmanWP
There was a pic of a magazine interview with a BAE rep that I saw a few years back (but is saved on a PC that died). It stated that the aperture bays have room for active components "should the customer request their development".

The -239 uses the APG-81 because it's freaking huge compared to traditional self-protection jammers. It's ability to put EW energy on target will only be surpassed by NGJ, and even then not the same power but it will have a later FOV and more bands that are covered.

btw, Now that we know it has the ALE... where is it deployed from? Given its length and that all the F-35's doors that can open in flight are easy to ID.... Where the heck is it?

We know that the flares are from the rear, right so I thought maybe rear-left... till I realised that area was taken up by the IPP exhaust for the F-35B which we know has the ALE.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 08:29
by garrya
SpudmanWP wrote:The -239 uses the APG-81 because it's freaking huge compared to traditional self-protection jammers. It's ability to put EW energy on target will only be surpassed by NGJ, and even then not the same power but it will have a later FOV and more bands that are covered.

I know , but i mean i can use APG-81 for frontal aspect while still have separate aperture for side and tail aspect, moreover a separate aperture will likely have wider bandwidth
SpudmanWP wrote:btw, Now that we know it has the ALE... where is it deployed from? Given its length and that all the F-35's doors that can open in flight are easy to ID.... Where the heck is it?

May be from the top door , behind the refuel door ?
Image

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 08:45
by SpudmanWP
That's the SatComm antenna

Image

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 08:54
by garrya
SpudmanWP wrote:That's the SatComm antenna

Image

wow where do you get those image from ? can i have the source ? :)
Btw , how about the underbelly bay that hold the hook ? , A and C version doesnt have hook so may be they can have the decoy there
Image

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 09:09
by mrigdon
garrya wrote:wow where do you get those image from ? can i have the source ? :)
Btw , how about the underbelly bay that hold the hook ? , A and C version doesnt have hook so may be they can have the decoy there


The A version has a hook. They've been testing it recently.

https://theaviationist.com/2016/05/20/t ... wards-afb/

And the C version better have a hook or else it's a one way trip off the carrier. :shock:

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 14:26
by hornetfinn
AFAIK, pretty much all self-protection jamming systems cover only front and rear sectors and have rather limited bandwidth for jamming. Also towed decoys have been found to be more effective than aircraft mounted jammers for protecting rear sector of fighter as they can also act as fake target if required and also because they have wider coverage due to being so far away from aircraft itself. I think F-35 will have roughly equal offensive EW coverage as best current operational systems and superior performance as individual systems. Together with VLO stealth and sensor fusion and networking, it probably has orders of magnitude better total performance.

With VLO stealth, a single F-35 can probably use only small number of T/R modules of AN/APG-81 for jamming purposes and radar performance will not be much affected.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 15:14
by popcorn
Nothing much on ALE-70 but should be similar to ALE-55.

http://www.militaryaerospace.com/articl ... decoy.html

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 16:22
by eloise
Since lower RCS reduces jamming power requirements, i reckon that it can make terrain bounce jamming useful even at high altitude ? what do you guys think?
Image

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 16:48
by SpudmanWP
garrya wrote:wow where do you get those image from ? can i have the source ? :)

That was in a PDF from Harris.com that I found a few years ago but I can't find it now (that's why I have imgur :) )

However, I do think I figured it out. The door that I had previously associated with the flares is likely the ALE door. My reasoning it two-fold, flare eject direction and interface size.

1st, let's look at the door in question from this pic.

Image

Note a few things. A: It ejects horizontally, B: It looks like it mounts 4 items across. Since we know the flares are 1 inch square, it seems like something much bigger goes here.

Here is the area in question with the dispencer removed

Image

2nd, assuming that the above is the ALE dispenser, where is the flare dispenser? Simple, right behind it. Lets take a close look at the area behind the ALE dispenser.

Image

A = ALE dispenser door
F (x2) = Flare doors

Note the "Beware of blast" warnings on both areas and that the weapons bay is right up against the flare doors. This means that they would eject perpendicular to the F-35 whereas the ALE is pointing aft in the traditional manner.

Here is a shot of the F-35 ejecting flares and you will note that

Image

If you zoom in, you will see the doors open. The position of the flares and the distance from the F-35 supports a perpendicular launch from the area in question.

Yes, I have a job, this isn't it, and yes, I have too much free time :)

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 17:04
by spazsinbad
From 1st 'SWP' photo above of an F-35 Rear End is zoom with ALE door open & from 2nd photo F-35B ALE door removed.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 17:18
by SpudmanWP
thanks for the zoom...

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 17:41
by cantaz
With regards to all aspect jamming, the F-35 does have a system that can selectively radiate in all directions, that being the MADL. For the same reason that the APG-81 might be able to jam outside of its optimal bands, there might be some future growth (classified capability) of the MADL as a defensive jammer, especially if they have/get GaN T/R modules.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 18:23
by SpudmanWP
Trigger warning... pure speculation ahead ;)

Zooming in on the PDF (attached) of the ASQ-239 reveals interesting aspects of the -239 apetures. They appear to have the traditional hill & valley layout of AESA T&R antenna apertures (ie, Tapered Slot Antenna aka Vivaldi antenna). One of the benefits of a Vivaldi antenna is that it is inherently a broadband antenna. Kind of makes you wonder about not only the -239's jamming capability, but also why the APG-81 uses a Vivaldi antenna instead of a tile-based AESA layout.

Do receive antennas also use the hill & valley layout as maybe needed for angular direction finding?

Image

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 18:53
by garrya
SpudmanWP wrote:2nd, assuming that the above is the ALE dispenser, where is the flare dispenser? Simple, right behind it. Lets take a close look at the area behind the ALE dispenser.

Image

A = ALE dispenser door
F (x2) = Flare doors

Note the "Beware of blast" warnings on both areas and that the weapons bay is right up against the flare doors. This means that they would eject perpendicular to the F-35 whereas the ALE is pointing aft in the traditional manner.
Here is a shot of the F-35 ejecting flares and you will note that
Image

You seem to be correct , btw, here is a gif of F-35 releasing flare , very big picture so we can clearly see the 2 small bay door open
https://gfycat.com/FormalCheapApatosaur

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 18:58
by SpudmanWP
nice gif... Google/YouTube did not come up with the source vid... likely buried in an "annual update" vid.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 19:00
by garrya
Here are some clearer pictures of F-35 Flares bay open
Image
Image
Image
Image
ALE-70 bay open
Image
viewtopic.php?f=22&t=27294&start=15

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 19:05
by garrya
SpudmanWP wrote:Do receive antennas also use the hill & valley layout as maybe needed for angular direction finding?

Image

hill , valley layout isnot needed for angular direction finding ,interferometry can be done with 2 antennas.
IMHO , the reason for the hill, valley layout is so that the jamming beam could be steered electronically.
SpudmanWP wrote:nice gif... Google/YouTube did not come up with the source vid... likely buried in an "annual update" vid.

I found that Gif purely by chance when looking for some Gif for my blog a while ago

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 19:16
by SpudmanWP
It's looking more and more like the ASQ-239 is active jamming capabilities outside of the APG-81.

Other things that it might be.. part of the IFF system or a way of sending midcourse updates to weapons that are not within the forward arc (ie update-able by the APG-81).

The plot thickens....

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 22:02
by SpudmanWP
The ALE-70(V) has a 400 Flight Hour limit
https://doni.documentservices.dla.mil/S ... 000.16.pdf

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 22:27
by neptune
SpudmanWP wrote:You need a VLO airframe in order for the -239 to be effective enough to do the job. Remember that the radar (ie the only jammer element) only covers the front aspect.


Spud, sorry for the misunderstanding,
... these a/c are getting the AESA to improve costs (time/ materials).

.... as this AESA upgrade is implemented, it appeared that these same a/c could replace their existing EW systems with a mature system (-239) that could be upgraded as the F-35/-239 is upgraded. This is not an alternate to the F-35/-239 but an improvement in their legacy SA and possibly another sensor node for an available F-35. Adding passive receiving sensors would not be an issue, as they are not LO.

IMHO
:)

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 22:29
by SpudmanWP
That makes more sense :)

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 23:38
by popcorn
SpudmanWP wrote:It's looking more and more like the ASQ-239 is active jamming capabilities outside of the APG-81.

Other things that it might be.. part of the IFF system or a way of sending midcourse updates to weapons that are not within the forward arc (ie update-able by the APG-81).

The plot thickens....

Could be the CNI shares the same emitters?

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 17 Oct 2016, 23:45
by SpudmanWP
Anything is possible...

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 18 Oct 2016, 00:02
by popcorn
SpudmanWP wrote:The ALE-70(V) has a 400 Flight Hour limit
https://doni.documentservices.dla.mil/S ... 000.16.pdf



Need to swap batteries? :D

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 18 Oct 2016, 00:17
by les_paul59
unfortunately we don't have all the specs on a system like the f-35's ew suite, but I think that the reason the U.S. is so confident in this jet is that the ew suite is a cut above everything else when combined with the vlo airframe and the radar.

The devil is always in the details

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 18 Oct 2016, 00:32
by SpudmanWP
popcorn wrote:
SpudmanWP wrote:The ALE-70(V) has a 400 Flight Hour limit
https://doni.documentservices.dla.mil/S ... 000.16.pdf



Need to swap batteries? :D


Likely heat & vibration

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 18 Oct 2016, 02:01
by wrightwing
The article says that the ASQ-239 has broadband self-protection jamming capabilities, among its other capabilities. The APG-81 isn't mentioned.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 18 Oct 2016, 04:14
by SpudmanWP
There is plenty of documentation talking about the interaction of the APG-81 and the ASQ-239 in the active jamming role.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 18 Oct 2016, 07:16
by garrya
eloise wrote:Since lower RCS reduces jamming power requirements, i reckon that it can make terrain bounce jamming useful even at high altitude ? what do you guys think?

Technically speaking , terrain bounce jamming can be thought about as standoff jamming , the case of normal fighter using direct jamming vs stealth fighter using terrain bounce jamming can be represented as follow ( the image get resize so please open in new tab to see full size) :
Image
Any math genius ? :mrgreen:

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 18 Oct 2016, 07:24
by garrya
Now that we know F-35 can carry ALE-70 , this beg a new question to speculate , how many of those can it carry ?

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 18 Oct 2016, 09:34
by hornetfinn
garrya wrote:Now that we know F-35 can carry ALE-70 , this beg a new question to speculate , how many of those can it carry ?


I would say not many as towed decoys are fairly large and take up quite a lot of space. I think usually these systems have two decoys to be used and I doubt there is space for more inside F-35. Besides, I don't think many would be needed in any event as it would be pretty hairy situation where you would need more than that.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 18 Oct 2016, 10:02
by garrya
hornetfinn wrote:I would say not many as towed decoys are fairly large and take up quite a lot of space. I think usually these systems have two decoys to be used and I doubt there is space for more inside F-35. Besides, I don't think many would be needed in any event as it would be pretty hairy situation where you would need more than that.

I think it can probably carry 4 decoys if we look at this photo
Image

Typhoon arrangement look like this , and it can have 2 decoy at wing tip
Image

F-16 have 4 towed decoy with this arrangement
Image
Image

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 18 Oct 2016, 10:31
by garrya
Because of eloisa question , i looked at some jamming vs radar problem , not sure if that just me or effect of jamming seem too good to be true ?
:shock:
weak jammer , high RCS and range burn through still extremely short ??????
Image

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 18 Oct 2016, 12:04
by XanderCrews
les_paul59 wrote:unfortunately we don't have all the specs on a system like the f-35's ew suite, but I think that the reason the U.S. is so confident in this jet is that the ew suite is a cut above everything else when combined with the vlo airframe and the radar.

The devil is always in the details




According to Marine general Amos a few years back F-35 is 85 percent as effective as an EA-6B...

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 18 Oct 2016, 13:17
by garrya
XanderCrews wrote:According to Marine general Amos a few years back F-35 is 85 percent as effective as an EA-6B...

In support jamming roles
in self protection jamming , f-35 will be much better.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 18 Oct 2016, 13:17
by hornetfinn
garrya wrote:hill , valley layout isnot needed for angular direction finding ,interferometry can be done with 2 antennas.
IMHO , the reason for the hill, valley layout is so that the jamming beam could be steered electronically.


That configuration could also be phased array antenna with receive only capability, with basically T/R modules without the "T". Phased array antenna would allow several high gain receive beams which would be limited with only number of receivers. Electronic steering works also in receive path. This means it'd be more sensitive than traditional antennas and could handle higher number of simultaneous signals. Restricting the system for receive only sounds a bit strange though as having full T/R modules would not be that much more complicated and would not lower the system performance as ESM system like it would've with other antenna systems. Maybe if there are space, heating or power restrictions that allows receive only system.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 18 Oct 2016, 13:33
by hornetfinn
garrya wrote:Because of eloisa question , i looked at some jamming vs radar problem , not sure if that just me or effect of jamming seem too good to be true ?
:shock:
weak jammer , high RCS and range burn through still extremely short ??????
Image


That's because the equation gives the maximum theoretical effectiveness for the jammer. The jammer is exactly at the same frequency as the radar and can concentrate the power directly against radar. Basically it's how the most basic radar systems would work against jammers. 100W of jamming power directly in band is actually a lot of jamming power. Real world radars have methods to give them much better chances against jamming like frequency hopping over wide bandwidth along with complex waveforms to increase required J/S ratio etc. Also radar antennas usually have higher gain than 30 dBi.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 18 Oct 2016, 13:55
by garrya
hornetfinn wrote:
That's because the equation gives the maximum theoretical effectiveness for the jammer. The jammer is exactly at the same frequency as the radar and can concentrate the power directly against radar. Basically it's how the most basic radar systems would work against jammers. 100W of jamming power directly in band is actually a lot of jamming power. Real world radars have methods to give them much better chances against jamming like frequency hopping over wide bandwidth along with complex waveforms to increase required J/S ratio etc. Also radar antennas usually have higher gain than 30 dBi.

That seem fair enough but aren't airborne radar limited in X band mostly (8-12 Ghz) the bandwidth is only 4 Ghz, i dont think spreading energy over a bandwidth of 4 Ghz would reduce jamming energy that much.
then there are many jammers with power > 100W too

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 18 Oct 2016, 22:07
by wrightwing
SpudmanWP wrote:There is plenty of documentation talking about the interaction of the APG-81 and the ASQ-239 in the active jamming role.

I realize that, but this article is suggesting that the ASQ-239 has jamming capabilities too, which wasn't necessarily acknowledged before.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 18 Oct 2016, 22:17
by SpudmanWP
wrightwing wrote:
SpudmanWP wrote:There is plenty of documentation talking about the interaction of the APG-81 and the ASQ-239 in the active jamming role.

I realize that, but this article is suggesting that the ASQ-239 has jamming capabilities too, which wasn't necessarily acknowledged before.


Which could simply be the towed decoy too.

The only thing that is known is what is unknown.... :roll:

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 19 Oct 2016, 05:51
by eloise
SpudmanWP wrote:Which could simply be the towed decoy too.

but that wouldn't make lots of sense
towed decoy cant jam frontal aspects and APG-81 would be limited in frequency (X band), I think it totally makes sense for ASQ-239 to have jamming capability

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 19 Oct 2016, 06:13
by popcorn
eloise wrote:
SpudmanWP wrote:Which could simply be the towed decoy too.

but that wouldn't make lots of sense
towed decoy cant jam frontal aspects and APG-81 would be limited in frequency (X band), I think it totally makes sense for ASQ-239 to have jamming capability

There's no silver bullet. Individual pieces of kit contribute to achieve the desired effect.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 19 Oct 2016, 08:58
by wrightwing
My takeaway is this- the title suggests that BAE is saying the ASQ-239 is more capable than previously admitted, and actually has broadband jamming capabilities, in addition to the X band jamming of the APG-81, and decoy functions.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 19 Oct 2016, 10:25
by eloise
garrya wrote:That seem fair enough but aren't airborne radar limited in X band mostly (8-12 Ghz) the bandwidth is only 4 Ghz, i dont think spreading energy over a bandwidth of 4 Ghz would reduce jamming energy that much.
then there are many jammers with power > 100W too

Let say the transmitting power of jammer is 1kW , instantaneous bandwidth of radar pulse is 40 Hz ,radar only operate in X band so maximum bandwidth of radar is 4Ghz , the jammer has to spread its power over 4000/40= 100 times compared to radar, so when they are overlap in frequency , jamming power in band is 1kW/100 = 10W.
Secondly, because jammer doesn't know exactly when radar transmit , it will have bigger duty cycle which will reduce peak power more

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 19 Oct 2016, 10:41
by eloise
Many fighter radar can actually operate outside X-band
EX :Apg-66v1
Image

Btw why APG-66v2 has such a narrow bandwidth compared to v1 version?

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 19 Oct 2016, 11:10
by hornetfinn
garrya wrote:
hornetfinn wrote:
That's because the equation gives the maximum theoretical effectiveness for the jammer. The jammer is exactly at the same frequency as the radar and can concentrate the power directly against radar. Basically it's how the most basic radar systems would work against jammers. 100W of jamming power directly in band is actually a lot of jamming power. Real world radars have methods to give them much better chances against jamming like frequency hopping over wide bandwidth along with complex waveforms to increase required J/S ratio etc. Also radar antennas usually have higher gain than 30 dBi.

That seem fair enough but aren't airborne radar limited in X band mostly (8-12 Ghz) the bandwidth is only 4 Ghz, i dont think spreading energy over a bandwidth of 4 Ghz would reduce jamming energy that much.
then there are many jammers with power > 100W too


4 GHz is actually a huge swath of bandwidth to jam. If we have 100 watts jammer, it would have only 0.025 Watts per MHz. That means the jammer ERP would actually be only 17 dBi instead of 53 dBi. That change would directly mean that burn through range would become about 16 km instead. Another thing is that required J/S is only 2 dB for jamming to be effective. With modern radars the processing gain of complex coded waveforms is much higher and can easily be 30-40 dB (or even higher). Since usually detection requires about 13 dB SNR, the required J/S would be 17 to 27 dB in this case. That would further increase the range to well over 100 km. 40 dB processing gain would bring this to 355 km or so. These calculations do not take into account many things like system losses in radar and jammer etc, but they give the general idea.

Sure there are higher powered self protection jammers, but not by that much. Usually we are talking about less than 1 kW of power. Radars also have higher antenna gain than 30 dBi. A typical fighter radar has antenna gain of 30-40 dBi and larger surveillance and ground based fire control radars can have even higher antenna gain.

The equation clearly shows the importance of low RCS and directional antennas for effective jamming against modern radars. No wonder VLO stealth along with GaN phased array antennas for both radars and jammers are sought after.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 19 Oct 2016, 11:49
by garrya
eloise wrote:Let say the transmitting power of jammer is 1kW , instantaneous bandwidth of radar pulse is 40 Hz ,radar only operate in X band so maximum bandwidth of radar is 4Ghz , the jammer has to spread its power over 4000/40= 100 times compared to radar, so when they are overlap in frequency , jamming power in band is 1kW/100 = 10W

Necessary jamming power reduce at the same rate as RCS , the target in earlier example has 10 sqm RCS , if we was to consider target with RCS = 1 sqm then suddenly 10W is more than enough.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 19 Oct 2016, 12:05
by garrya
hornetfinn wrote:4 GHz is actually a huge swath of bandwidth to jam. If we have 100 watts jammer, it would have only 0.025 Watts per MHz.

But frequency range ( bandwidth) of a complex pulse would be much wider than 1 MHz though , is it not ?

hornetfinn wrote: That means the jammer ERP would actually be only 17 dBi instead of 53 dBi. That change would directly mean that burn through range would become about 16 km instead.

TBH iam not so good with number so can you elaborate a bit more ?
anyway, 16 km burn through range still seem extremely short for target with RCS = 10 m2 , that is well within range of IR sensor
hornetfinn wrote:Another thing is that required J/S is only 2 dB for jamming to be effective. With modern radars the processing gain of complex coded waveforms is much higher and can easily be 30-40 dB (or even higher).

That a fair point but as far as i know , while angle jamming technique require very high J/S ratio to be effective , range jamming technique doesnt seem to need J/S ratio that high
Image

hornetfinn wrote:Since usually detection requires about 13 dB SNR, the required J/S would be 17 to 27 dB in this case. That would further increase the range to well over 100 km. 40 dB processing gain would bring this to 355 km or so.

I dont really get this part , can you elaborate ?


hornetfinn wrote: Radars also have higher antenna gain than 30 dBi. A typical fighter radar has antenna gain of 30-40 dBi and larger surveillance and ground based fire control radars can have even higher antenna gain.

I know that ground radar can have very high gain ( their size is practically unlimited after all ) , but i dont think average fighter radar ( aka APG-81 ) has higher gain than 30 dB given their size and operating frequency

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 19 Oct 2016, 12:09
by popcorn
See hornetfinn's thread re potential of AESA tech in a jamming role. Hard to believe that this would not have been exploited in the years since the patent was filed.

viewtopic.php?f=38&t=26802

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 19 Oct 2016, 12:11
by garrya
There was another example regard standoff jamming problem , the jammer was 30km from radar , target RCS is 10 sqm , and burn through range is merely 2 km ( this jammer seem to have very good gain and transmitting power though)
Image

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 20 Oct 2016, 00:37
by eloise
garrya wrote:But frequency range ( bandwidth) of a complex pulse would be much wider than 1 MHz though , is it not ?

Compressed pulse aside , bandwidth of a square pulse if a good range resolution is needed , actually pretty narrow ,around 1 MHz for 150 meters range resolution.
Image

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 20 Oct 2016, 10:58
by garrya
^That seem reasonable enough , but also kind of weird, because then a short pulse with very high peak power would be harder to jam compared to a long compressed pulse with low peak power.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 20 Oct 2016, 12:12
by hornetfinn
garrya wrote:
hornetfinn wrote:4 GHz is actually a huge swath of bandwidth to jam. If we have 100 watts jammer, it would have only 0.025 Watts per MHz.

But frequency range ( bandwidth) of a complex pulse would be much wider than 1 MHz though , is it not ?


Not that much wider as eloise said and besides all modern military (and almost all commercial) radars (since 1950s) employ pulse compression (PC) technique which makes a huge difference in ECM resistance. Your example was using a very basic pulse radar with no PC at all.

garrya wrote:
hornetfinn wrote: That means the jammer ERP would actually be only 17 dBi instead of 53 dBi. That change would directly mean that burn through range would become about 16 km instead.

TBH iam not so good with number so can you elaborate a bit more ?
anyway, 16 km burn through range still seem extremely short for target with RCS = 10 m2 , that is well within range of IR sensor


100 Watts is 50 dBm and along with3 dBi Antenna that becomes 53 dBm. MHz is the basic unit used in these calculations and 100 Watts divided by 4000 (4 GHz) becomes 0.025 Watts which is how much jamming energy there is per MHz. That's equal to 14 dBm. With the 3 dBi antenna, that becomes 17 dBm to be used in these calculations.

Yes, 16 km BT range is very short, but that's only accounting for the jamming energy which is spread over such a large bandwidth. When you take into account pulse compression, doppler processing and other such methods, the whole thing changes drastically as radar gets huge performance improvements due to processing gain.

garrya wrote:
hornetfinn wrote:Another thing is that required J/S is only 2 dB for jamming to be effective. With modern radars the processing gain of complex coded waveforms is much higher and can easily be 30-40 dB (or even higher).

That a fair point but as far as i know , while angle jamming technique require very high J/S ratio to be effective , range jamming technique doesnt seem to need J/S ratio that high
Image


You may notice that range jamming techniques are only under Pulsed radar type. That means basic pulse radar without any of the techniques I mentioned. Pretty much all modern radars use monopulse technique which makes them very hard to jam with techniques that worked well against pulsed radars.

garrya wrote:
hornetfinn wrote:Since usually detection requires about 13 dB SNR, the required J/S would be 17 to 27 dB in this case. That would further increase the range to well over 100 km. 40 dB processing gain would bring this to 355 km or so.

I dont really get this part , can you elaborate ?


I meant processing gain of 30 to 40 dB where we subtract the required SNR for detection (13 dB is used often as rule of thumb for automatic detectors) which makes the required J/S 17 to 27 dB.

garrya wrote:
hornetfinn wrote: Radars also have higher antenna gain than 30 dBi. A typical fighter radar has antenna gain of 30-40 dBi and larger surveillance and ground based fire control radars can have even higher antenna gain.

I know that ground radar can have very high gain ( their size is practically unlimited after all ) , but i dont think average fighter radar ( aka APG-81 ) has higher gain than 30 dB given their size and operating frequency


You can easily calculate radar antenna gains with these formulas:
http://www.phys.hawaii.edu/~anita/new/p ... tennas.pdf

With 50 percent efficiency a 60 cm antenna of F-16 AN/APG-68 has gain of 32.55 dB in middle of X-band. For 91.4 cm dish for F-14 and F-15 we get antenna gain of 36.2 dB. I've seen figures of about 37 dB for F-14 antenna, which would suggest antenna efficiency of about 60 percent which is possible for planar array radar. AESA antennas can have efficiency of 70 to 80 percent and that would result in 1-2 dB higher antenna gain. With higher frequency gain increases and lower frequency gain decreases.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 20 Oct 2016, 13:13
by garrya
hornetfinn wrote:100 Watts is 50 dBm and along with3 dBi Antenna that becomes 53 dBm. MHz is the basic unit used in these calculations and 100 Watts divided by 4000 (4 GHz) becomes 0.025 Watts which is how much jamming energy there is per MHz. That's equal to 14 dBm. With the 3 dBi antenna, that becomes 17 dBm to be used in these calculations.
Yes, 16 km BT range is very short

If the jamming power is 1 kW but J/S is 20 dB
what would be the Range burn through for our calculation ?

hornetfinn wrote:You may notice that range jamming techniques are only under Pulsed radar type. That means basic pulse radar without any of the techniques I mentioned. Pretty much all modern radars use monopulse technique which makes them very hard to jam with techniques that worked well against pulsed radars. .

AFAIK , monopulse technique is only for better angle tracking capabilities , range tracking should be unaffected , and even monopulse seem to be rather vulnerable to blinking jamming
Image

hornetfinn wrote:SinI meant processing gain of 30 to 40 dB where we subtract the required SNR for detection (13 dB is used often as rule of thumb for automatic detectors) which makes the required J/S 17 to 27 dB..

So basically , for example : if APG-81 detect a target at 100 km , the SNR has to be at least 13dB ? shouldn't more sensitive receiver and better processing power require smaller SNR ?

hornetfinn wrote:You can easily calculate radar antenna gains with these formulas:
http://www.phys.hawaii.edu/~anita/new/p ... tennas.pdf
With 50 percent efficiency a 60 cm antenna of F-16 AN/APG-68 has gain of 32.55 dB in middle of X-band. For 91.4 cm dish for F-14 and F-15 we get antenna gain of 36.2 dB. I've seen figures of about 37 dB for F-14 antenna, which would suggest antenna efficiency of about 60 percent which is possible for planar array radar. AESA antennas can have efficiency of 70 to 80 percent and that would result in 1-2 dB higher antenna gain. With higher frequency gain increases and lower frequency gain decreases.

Doesnt seem to be very significant to be fair

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 20 Oct 2016, 14:05
by castlebravo
garrya wrote:
hornetfinn wrote:100 Watts is 50 dBm and along with3 dBi Antenna that becomes 53 dBm. MHz is the basic unit used in these calculations and 100 Watts divided by 4000 (4 GHz) becomes 0.025 Watts which is how much jamming energy there is per MHz. That's equal to 14 dBm. With the 3 dBi antenna, that becomes 17 dBm to be used in these calculations.
Yes, 16 km BT range is very short

If the jamming power is 1 kW but J/S is 20 dB
what would be the Range burn through for our calculation ?

hornetfinn wrote:You may notice that range jamming techniques are only under Pulsed radar type. That means basic pulse radar without any of the techniques I mentioned. Pretty much all modern radars use monopulse technique which makes them very hard to jam with techniques that worked well against pulsed radars. .

AFAIK , monopulse technique is only for better angle tracking capabilities , range tracking should be unaffected , and even monopulse seem to be rather vulnerable to blinking jamming
Image

hornetfinn wrote:SinI meant processing gain of 30 to 40 dB where we subtract the required SNR for detection (13 dB is used often as rule of thumb for automatic detectors) which makes the required J/S 17 to 27 dB..

So basically , for example : if APG-81 detect a target at 100 km , the SNR has to be at least 13dB ? shouldn't more sensitive receiver and better processing power require smaller SNR ?

hornetfinn wrote:You can easily calculate radar antenna gains with these formulas:
http://www.phys.hawaii.edu/~anita/new/p ... tennas.pdf
With 50 percent efficiency a 60 cm antenna of F-16 AN/APG-68 has gain of 32.55 dB in middle of X-band. For 91.4 cm dish for F-14 and F-15 we get antenna gain of 36.2 dB. I've seen figures of about 37 dB for F-14 antenna, which would suggest antenna efficiency of about 60 percent which is possible for planar array radar. AESA antennas can have efficiency of 70 to 80 percent and that would result in 1-2 dB higher antenna gain. With higher frequency gain increases and lower frequency gain decreases.

Doesnt seem to be very significant to be fair


A 6 dBi improvement in antenna gain would give you something like double the range since you are improving total system gain by 12 dBi (+6 dBi on both transmit and receive).

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 20 Oct 2016, 17:25
by garrya
castlebravo wrote:A 6 dBi improvement in antenna gain would give you something like double the range since you are improving total system gain by 12 dBi (+6 dBi on both transmit and receive).

Gain on receiving phase here can probably be ignored because radar will receive jamming signals too

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 20 Oct 2016, 20:23
by eloise
There is one easier way to settle this debate, we should as gums if F-16 using ALQ-184 or any other jamming pod can get into the merge with F-15 without being engaged from BVR, then go from there

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 21 Oct 2016, 09:01
by garrya
eloise wrote:There is one easier way to settle this debate, we should as gums if F-16 using ALQ-184 or any other jamming pod can get into the merge with F-15 without being engaged from BVR, then go from there

35AoA and spazsinbad are also pilot AFAIK, maybe they can contribute their opinion

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 21 Oct 2016, 09:17
by hornetfinn
garrya wrote:
hornetfinn wrote:100 Watts is 50 dBm and along with3 dBi Antenna that becomes 53 dBm. MHz is the basic unit used in these calculations and 100 Watts divided by 4000 (4 GHz) becomes 0.025 Watts which is how much jamming energy there is per MHz. That's equal to 14 dBm. With the 3 dBi antenna, that becomes 17 dBm to be used in these calculations.
Yes, 16 km BT range is very short

If the jamming power is 1 kW but J/S is 20 dB
what would be the Range burn through for our calculation ?


In that case the 20Log Rbt = 120 - 24 -71 + 10 + 2 = 37

Rbt = Antilog (37 / 20) = Antilog (1.85) = 70.8 km.

That's assuming the jammer jams the whole 4 GHz X-Band with 1 kW of power. If the jammer is exactly at the same frequency and bandwidth as the radar the range would be slightly less than 800 meters or about 1000 times shorter.

garrya wrote:
hornetfinn wrote:You may notice that range jamming techniques are only under Pulsed radar type. That means basic pulse radar without any of the techniques I mentioned. Pretty much all modern radars use monopulse technique which makes them very hard to jam with techniques that worked well against pulsed radars. .

AFAIK , monopulse technique is only for better angle tracking capabilities , range tracking should be unaffected , and even monopulse seem to be rather vulnerable to blinking jamming
Image


Range gate jamming techniques can be pretty easily be dealt with using variable PRF (jittering), monitoring the received signal strength, using leading edge tracking and very importantly using pulse to pulse frequency hopping. Range gate jamming techniques require that radar signal is replicated with high precision and very fast and that is very difficult with modern radars which incidentally also use all of the techniques mentioned. DRFM techniques can make ange gate jamming techniques effective but it's by no means any magic bullet. It might be able to break the radar track but modern AESAs can regain tracking very quickly, so the usefulness is somewhat questionable. Also if radar uses leading-edge tracking, even DRFM range gate jamming is not effective. Monopulse technique was developed for better angle tracking but it also protects against range gate jamming as the radar has more signal information to detect such jamming. It makes the jammer needing to be far more precise and subtle in operation to work.

Blinking jamming is formation jamming that requires two or more aircraft synchronously doing jamming at certain distance between each other and radar being certain simple type of mechanical tracking radar. It tries to overwhelm the angle tracking servo of the antenna as the radar moves the antenna from one jamming source to another. With modern systems it's basically only radar guided missiles that might be affected and even then it requires that missile seeker was designed without this in mind. Also if missile gets updates from outside, this method would have no effect.

garrya wrote:
hornetfinn wrote:SinI meant processing gain of 30 to 40 dB where we subtract the required SNR for detection (13 dB is used often as rule of thumb for automatic detectors) which makes the required J/S 17 to 27 dB..

So basically , for example : if APG-81 detect a target at 100 km , the SNR has to be at least 13dB ? shouldn't more sensitive receiver and better processing power require smaller SNR ?


That's just a rule of thumb and exact details depend on system. However, the SNR is a function of probability of detection and false alarm rate and these are universal. More sensitive receiver lowers the SNR degradation in the radar system but does not affect the required SNR itself. Better processing can affect the required SNR especially with multiple detections. 13 dB is a rule of thumb for a single pulse detection. Things can get pretty complicated with real world radar systems as they pretty much all employ pulse integration which can improve required SNR significantly.

garrya wrote:
hornetfinn wrote:You can easily calculate radar antenna gains with these formulas:
http://www.phys.hawaii.edu/~anita/new/p ... tennas.pdf
With 50 percent efficiency a 60 cm antenna of F-16 AN/APG-68 has gain of 32.55 dB in middle of X-band. For 91.4 cm dish for F-14 and F-15 we get antenna gain of 36.2 dB. I've seen figures of about 37 dB for F-14 antenna, which would suggest antenna efficiency of about 60 percent which is possible for planar array radar. AESA antennas can have efficiency of 70 to 80 percent and that would result in 1-2 dB higher antenna gain. With higher frequency gain increases and lower frequency gain decreases.

Doesnt seem to be very significant to be fair


Do you mean AESA antenna gain over MSA antenna? That's just one improvement and the difference alone means 15 to 30 percent increase in effective range. It doesn't mean that much for main lobe jamming resistance alone, but due to much lower sidelobes makes sidelobe jamming and detectability of radar much harder. Of course electronic scanning also makes the job of jammer much harder as there is no way of predicting when the main lobe will be directed towards it. Jammers can predict the time when they can do their work against MSA radars, but that's not possible with phased array radars unless they are really badly designed. Of course the difference also means that AESA radar will have 15 to 30 percent range advantage against MSA or PESA radars. And that's just with having better antenna gain. Then we have higher average power, lower losses, much wider total bandwidth, waveform agility and other such AESA advantages and suddenly all add up to huge advantages and threre is a lot of room for development in each of these areas still.

Going from 30 to say 36 dB antenna gain means that the BT range is doubled. Doesn't mean much if BT range is the original 251 meters, but is huge when BT is say 100 km for 30 dB antenna and 200 km for 36 dB antenna.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 21 Oct 2016, 11:01
by garrya
hornetfinn wrote:In that case the 20Log Rbt = 120 - 24 -71 + 10 + 2 = 37

Rbt = Antilog (37 / 20) = Antilog (1.85) = 70.8 km.

That's assuming the jammer jams the whole 4 GHz X-Band with 1 kW of power. If the jammer is exactly at the same frequency and bandwidth as the radar the range would be slightly less than 800 meters or about 1000 times shorter.

burn through range square is proportional to RCS , so if the burn through distance against target with RCS = 10 m2 is 70.8 km , then the burn through distance against target with RCS =1 m2 is 20 km , hmm seem very short , that near visual range already
Image

hornetfinn wrote:Range gate jamming techniques can be pretty easily be dealt with using variable PRF (jittering), monitoring the received signal strength, using leading edge tracking and very importantly using pulse to pulse frequency hopping

Iam under the impression that PRF jittering and frequency hopping can be dealt with by spread out jamming power for the whole spectrum (barrage noise) ?

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 21 Oct 2016, 13:11
by hornetfinn
garrya wrote:
hornetfinn wrote:In that case the 20Log Rbt = 120 - 24 -71 + 10 + 2 = 37

Rbt = Antilog (37 / 20) = Antilog (1.85) = 70.8 km.

That's assuming the jammer jams the whole 4 GHz X-Band with 1 kW of power. If the jammer is exactly at the same frequency and bandwidth as the radar the range would be slightly less than 800 meters or about 1000 times shorter.

burn through range square is proportional to RCS , so if the burn through distance against target with RCS = 10 m2 is 70.8 km , then the burn through distance against target with RCS =1 m2 is 20 km , hmm seem very short , that near visual range already
Image


That just shows how important RCS reduction is for reducing detectability and how it works with jamming. Of course that's still pretty far from realistic modern radar and jammer system. The example is just a very basic one. In real world radars have much bigger processing and antenna gains. Jammers on the other hand will try to use narrower bandwidths and combination of jamming techniques to counter that. Generally no realistic jammer is going to have that huge advantage against realistic radar system. Some WW2 radar types with one fixed frequency might be that easily jammed, but not more modern ones.

garrya wrote:
hornetfinn wrote:Range gate jamming techniques can be pretty easily be dealt with using variable PRF (jittering), monitoring the received signal strength, using leading edge tracking and very importantly using pulse to pulse frequency hopping

Iam under the impression that PRF jittering and frequency hopping can be dealt with by spread out jamming power for the whole spectrum (barrage noise) ?


Barrage noise jamming is pretty sure way of jamming everything if you have enough power. Problem however is that it requires a huge power advantage to really work against modern radars. That can be achieved by having huge amount of RF power which is bad because you become a very bright radar beacon for everybody. Besides, even a 1 square meter RCS fighter would require a huge amount of power (like Megawatts) to really be able to be effective at realistic ranges and that kind of power would be impossible to fit inside fighter aircraft. Even dedicated jammer aircraft can generate kilowatts of power.

Another way is to have highly directional jamming antennas which is good if you can direct the beam to right direction but bad if you can't (no effect if radar is not inside the jamming beam). Another good way is to have very smart jamming methods which lowers the power requirements and allows better response to radars. A really good way is to reduce your own RCS as that doesn't have any drawbacks for effectiveness like other methods. Having 100 times lower RCS is a really good thing without jamming and with jamming it's really great. You might notice that F-35 (and F-22 I'm sure) employ all of these methods and latest 4th gen fighters are trying to do their best in all areas. Of course 4th gen fighters can't beat the 30-50 dB RCS advantage F-35 and F-22 have due to their VLO stealth. That'd require having 100-10,000 times more jamming power or smarter jamming systems. Of course either is highly doubtful.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 21 Oct 2016, 15:03
by garrya
hornetfinn wrote:In that case the 20Log Rbt = 120 - 24 -71 + 10 + 2 = 37
Rbt = Antilog (37 / 20) = Antilog (1.85) = 70.8 km.

That's assuming the jammer jams the whole 4 GHz X-Band with 1 kW of power. If the jammer is exactly at the same frequency and bandwidth as the radar the range would be slightly less than 800 meters or about 1000 times shorter.
That just shows how important RCS reduction is for reducing detectability and how it works with jamming. Of course that's still pretty far from realistic modern radar and jammer system. The example is just a very basic one. In real world radars have much bigger processing and antenna gains. Jammers on the other hand will try to use narrower bandwidths and combination of jamming techniques to counter that. Generally no realistic jammer is going to have that huge advantage against realistic radar system. Some WW2 radar types with one fixed frequency might be that easily jammed, but not more modern ones.
Barrage noise jamming is pretty sure way of jamming everything if you have enough power. Problem however is that it requires a huge power advantage to really work against modern radars. Besides, even a 1 square meter RCS fighter would require a huge amount of power (like Megawatts) to really be able to be effective at realistic ranges and that kind of power would be impossible to fit inside fighter aircraft. Even dedicated jammer aircraft can generate kilowatts of power.

Based on our original example , if we modify the number a tiny bit :
if the jammer power is 1 kW
jammer gain is 3dBi
radar power is 10 kW
radar gain = 30dBi
J/S ratio required is 20 dB
operating band width of radar is between 8-12 Ghz
assuming the kind of jamming used is barrage noise so factors like PRF jittering and frequency hopping , pulse compression can be ignored
the burn through distance would be 70 km if target RCS is 10 m2 , about 20 km if target RCS is 1 m2 and so on , i dont think much more power will be required because 20 km burn through distance seem good enough.
Then one thing iam not so clear about the original function ,when they give number for the jammer and radar effective radiated power , are those average power or peak ? , 10 kW average power for airborne fighter radar seem overly high , i would think about 2-3 kW top.
Moreover, iam thinking , since we know AESA radar can be used in jamming role , what if the legacy fighter just use its radar for jamming ( since obviously it wont be able to detect stealth aircraft by its radar anyway) ? then we have jammer gain and effective radiated power equal to radar ?????


hornetfinn wrote:That can be achieved by having huge amount of RF power which is bad because you become a very bright radar beacon for everybody.

to be fair though , the same thing can be said when aircraft using their radar , even though to lesser extent. I know that there are LPI radar and what not , but still , if the small GPS antenna in mobiles phone , JDAM can detect GPS signal from satellite hundred thounsand miles aways then i think modern RWR should do well again radar at distance 200 km or less.
hornetfinn wrote: Another good way is to have very smart jamming methods which lowers the power requirements and allows better response to radars. A really good way is to reduce your own RCS as that doesn't have any drawbacks for effectiveness like other methods. Having 100 times lower RCS is a really good thing without jamming and with jamming it's really great. You might notice that F-35 (and F-22 I'm sure) employ all of these methods and latest 4th gen fighters are trying to do their best in all areas. Of course 4th gen fighters can't beat the 30-50 dB RCS advantage F-35 and F-22 have due to their VLO stealth. That'd require having 100-10,000 times more jamming power or smarter jamming systems. Of course either is highly doubtful.

This is undeniable , ofcourse low RCS can bring unparalleled jamming advantages , i agree that legacy aircraft wont be able to compete with fifth gen in SEAD , the gap is too enormous. However, in air to air role , i am thinking that a 4 gen fighter , with powerful enough jammer can reduce fighter radar burn through distance down to near visual range ( since fighter radar isnt really that powerful after all ).While the jammer on stealth aircraft would still be alot more effective , it is irrelevance in this case because if the jammer on legacy aircraft can bring burn through distance down to let say 20-25 km , then even if the jammer on VLO platform can bring burn through distance down to 2 km , it still doesnt matter , because at those distance electro optic sensors should work quite well.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 22 Oct 2016, 10:02
by eloise
To me that is key: it is not only stealth; it is the combination of the EOS and the radar to be able to build a comprehensive picture. In that engagement I talked about at Nellis, in Red Flag, the ability to be in a cockpit with a God’s-eye view of what is going on in the world was such an advantage over a fourth-generation fighter – and arguably one of the best fourth-generation fighters in existence, the F15. But even with a DRFM jamming pipe, we still had no chance in those particular engagements.

https://theaviationist.com/2013/06/19/f ... by-rafale/
If we were to believe the word of F-15 pilot who join exercise vs F-22 then jamming pod still doesnt help him get into visual range.
And GaN modules are said to have much wider bandwidth compare to GaAs modules so that will improve radar jamming resistance significantly in future.APG-81 will have GaN sooner or later but stealth cant be retrofitted to legacy aircraft .

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 22 Oct 2016, 17:23
by eloise
garrya wrote:assuming the kind of jamming used is barrage noise so factors like PRF jittering and frequency hopping , pulse compression can be ignored

Actually, pulse compression will reduce J/S by 30dB
Pulse compression
Image

Frequency hoping
Image
Image

PRF jittering
Image
https://books.google.co.uk/books?id=foY ... &q&f=false

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 23 Oct 2016, 00:20
by eloise
garrya wrote:for example : if APG-81 detect a target at 100 km , the SNR has to be at least 13dB ?

The require SNR ratio for detection actually depending on the probability of detection (Pd) and probably of false alarm (Pfa) ,Western standard for radar detection is 90 Pd and 10^-6 Pfa , so that measured to about 13 dB SNR
Image

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 23 Oct 2016, 15:06
by garrya
That very informative post, i didnt realize pulse compression reduce J/S ratio that much , but wouldnt pulse compression and frequency agility counter the other ? since radar practically spreading out its energy over a while bandwidth in pulse compression instead concentrated in a narrow frequency ( longer the pulse the wider the bandwidth)

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 24 Oct 2016, 14:04
by hornetfinn
garrya wrote:That very informative post, i didnt realize pulse compression reduce J/S ratio that much , but wouldnt pulse compression and frequency agility counter the other ? since radar practically spreading out its energy over a while bandwidth in pulse compression instead concentrated in a narrow frequency ( longer the pulse the wider the bandwidth)


Yes, pulse compression is a huge thing for radar performance in many ways. Pulse compression and frequency agility do not counter or affect negatively to each other at all and actually are almost always used together. There are many pulse compression techniques used, but they all have some things in common. They transmit a relatively long (in time) pulses which are divided into smaller parts which can be though as subpulses where pulse length is much shorter. The frequency or phase is usually changed between these so called subpulses to get more information from the target to improve radar resolution and resistance to jamming. Basically the pulse compression system transmits long pulses to have a lot of average power in the pulse. While receiving, it handles the smaller parts (subpulses) on their own and can thus get very high range resolution as that is inveresely proportional to pulse length. Then the pulse frequency can be changed when the next long pulse is sent. Quite often modern systems use phase coding within pulses (frequency stays the same) or frequency is changed within a narrow bandwidth between subpulses and make bigger change in frequency between long pulses. Another advantage with pulse compression is that radar can use very powerful pulses that are not easily detectable for outsider who does not know how the radar signal is coded. In modern digital pulse compression systems the frequency and/or phase modulation is pseudorandom. This way powerful long pulses do not show up for outsider as the power is distributed in phase and frequency. Without knowing the code, pulses don't show up from background noise. Modern jammers and ESM systems try to use some form of partially matched filtering (educated guess about coding scheme) to detect such radars. Radar itself knows what it transmits and can use fully matched filtering and gets a big processing gain compared to EW/ESM systems.

Actually the wide bandwidth can be had with short pulses as there can be a lot of them. A long pulse can also have wide bandwidth with chirping where frequency is changed within pulse.

And thank you eloise for those very good posts about the issue.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 24 Oct 2016, 14:17
by hornetfinn
garrya wrote:
hornetfinn wrote:That can be achieved by having huge amount of RF power which is bad because you become a very bright radar beacon for everybody.

to be fair though , the same thing can be said when aircraft using their radar , even though to lesser extent. I know that there are LPI radar and what not , but still , if the small GPS antenna in mobiles phone , JDAM can detect GPS signal from satellite hundred thounsand miles aways then i think modern RWR should do well again radar at distance 200 km or less.


The detectability difference between jammer and radar is huge. Radar transmits very narrow and short lived beams which makes detecting them very hard. Another thing is the modern pulse compression techniques can make it very hard to detect the radar signals from background noise even if the radar is transmitting with a lot of power. This is because the signal is spread in both frequency and phase as I noted in previous message. Without knowing how this is done, it can be very difficult to detect the radar signals.

Jammer on the other hand must transmit much wider beams to do effective jamming and most jammer systems transmit very wide beams. Jammers also must use waveforms that maximize the jamming effect on enemy radars and this can only be achieved with easily detectable signals. Same as GPS signal can be easily detectable as the signal was designed to be just that. F-35 for example will have nice advantage as it has very low RCS and thus power required for effective jamming is very low also. Besides using high gain antenna of the radar for jamming will also make it harder for most sensitive enemy systems (dedicated ESM platforms) to detect the jamming signals.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 25 Oct 2016, 13:44
by hornetfinn
I've been wondering about this: http://www.codeonemagazine.com/f35_arti ... tem_id=182

“This jet isn’t just about the weapons — it’s a game-changing capability. The Tornado GR.4 can't just stroll into a double digit SAM MEZ [Missile Engagement Zone]. In the F-35 I can generate a wormhole in the airspace and lead everyone through it. There isn’t another platform around that can do that. This isn’t all about height and supercruise speed — it’s the ability to not be seen,” added Beck.


I think this means F-35 will just get close with SAM systems or other engagement radar systems and do powerful and precisely targeted stand-in jamming from close range and makes the system unable to engage even unstealthy aircraft. As can be seen with stand-off jamming burn-through equation garrya posted in previous page, the range where jamming is done makes a huge difference. If F-35 can sit at say 50 km away and legacy stand-off jammer has to sit 200 km away, F-35 requires 16 times less power to achieve the same jamming effectiveness to protect the other aircraft if all else remains unaffected.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 25 Oct 2016, 14:22
by popcorn
I guess the jamming is part of the story. Also being able to detect and exploit holes in the IADS.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 26 Oct 2016, 02:17
by garrya
hornetfinn wrote:Yes, pulse compression is a huge thing for radar performance in many ways. Pulse compression and frequency agility do not counter or affect negatively to each other at all and actually are almost always used together. There are many pulse compression techniques used, but they all have some things in common. They transmit a relatively long (in time) pulses which are divided into smaller parts which can be though as subpulses where pulse length is much shorter. The frequency or phase is usually changed between these so called subpulses to get more information from the target to improve radar resolution and resistance to jamming. Basically the pulse compression system transmits long pulses to have a lot of average power in the pulse. While receiving, it handles the smaller parts (subpulses) on their own and can thus get very high range resolution as that is inveresely proportional to pulse length. Then the pulse frequency can be changed when the next long pulse is sent. Quite often modern systems use phase coding within pulses (frequency stays the same) or frequency is changed within a narrow bandwidth between subpulses and make bigger change in frequency between long pulses.
.
I mean if the compressed pulse consist of different frequency , shouldn't the matched filter allow signal/energy from much wider frequency range get into receiver ? the compressed chirp pulse seem to have very wide band width too
Image
Image
Image
Image

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 26 Oct 2016, 02:20
by garrya
hornetfinn wrote:Quite often modern systems use phase coding within pulses (frequency stays the same) .

Wouldn't number of possible phase combination is much more limited compared to frequency ?

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 26 Oct 2016, 11:54
by hornetfinn
garrya wrote:
hornetfinn wrote:Quite often modern systems use phase coding within pulses (frequency stays the same) .

Wouldn't number of possible phase combination is much more limited compared to frequency ?


Yes, phase combinations are very limited. In binary phase codes it's as name suggest binary with two states. Polyphase codes can have more states, but it's still limited to fairly small number of states. Anyway, in phase coding a long pulse is divided to extremely short subpulses which are coded by varying the phase. Bandwidth of such binary phase coded signal is B=1/τ where τ is the code subpulse length. So the shorter the subpulse length, the wider the bandwidth of the signal. Resolution is also similarly affected and short subpulses mean higher resolution. It's basically like binary data with 0 and 1 being used to code information and stringing more of them together means more data can be transmitted.

Using phase modulation system it's possible to transmit more information than using frequency modulation as it allows more efficient use of signal bandwidth to transmit information. It's rather complicated and very math-intensive area and very difficult to describe. Of course both phase and frequency can be modulated at the same time or frequency can be hopped with each pulse but pulse compression done with phase coding (pulse frequency stays the same). Together these will give radar very significant processing gain advantage against jammer and thus increase J/S ratio for successful jamming significantly. Of course there are jamming methods to reverse that and DRFM is the name of the game in modern jammers. However even DRFM and such methods will benefit from low RCS just as much as basic noise jammer. Also having high gain jamming antenna does the same. F-35 has both which makes it really great jamming platform.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 26 Oct 2016, 13:10
by eloise
Forms of pulse compression :
Image

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 26 Oct 2016, 13:39
by hornetfinn
garrya wrote: I mean if the compressed pulse consist of different frequency , shouldn't the matched filter allow signal/energy from much wider frequency range get into receiver ? the compressed chirp pulse seem to have very wide band width too


That's true in chirp type radar, although the effect of increased processing gain and the need for jammer to use wider bandwidth to counter this far outweight the negative effect.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 26 Oct 2016, 13:41
by hornetfinn
Thanks eloise, very nice table!

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 27 Oct 2016, 00:08
by garrya
hornetfinn wrote:That's true in chirp type radar, although the effect of increased processing gain and the need for jammer to use wider bandwidth to counter this far outweight the negative effect.

Iam not sure if processing gain can really counter the negative effect of spreading signal over wide frequency range though.For example : if radar can operate between 8-12 Ghz ,it operating frequency jumping randomly 4 Ghz total bandwidth , unable to predict pattern , jammer has to distribute energy over the whole frequency range, for a normal pulse with bandwidth of only 1 Mhz ,then only 0.025% of jamming power will get into radar receiver. For a compressed pulse with 1 Ghz bandwidth ,about 25% of jamming power will get into radar receiver. That quite a big different of around 30dB
hornetfinn wrote:Yes, phase combinations are very limited. In binary phase codes it's as name suggest binary with two states. Polyphase codes can have more states, but it's still limited to fairly small number of states. Anyway, in phase coding a long pulse is divided to extremely short subpulses which are coded by varying the phase.Using phase modulation system it's possible to transmit more information than using frequency modulation as it allows more efficient use of signal bandwidth to transmit information

According to this http://www.radartutorial.eu/08.transmit ... on.en.html phase coded pulse compression seem to have very low compression ratio ,maximum value is only 13 ( or is that only for Baker code ? )

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 27 Oct 2016, 02:46
by garrya
eloise wrote:Forms of pulse compression :
Image

What is a passive phase coded compression ?

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 27 Oct 2016, 13:26
by hornetfinn
garrya wrote:
hornetfinn wrote:That's true in chirp type radar, although the effect of increased processing gain and the need for jammer to use wider bandwidth to counter this far outweight the negative effect.

Iam not sure if processing gain can really counter the negative effect of spreading signal over wide frequency range though.For example : if radar can operate between 8-12 Ghz ,it operating frequency jumping randomly 4 Ghz total bandwidth , unable to predict pattern , jammer has to distribute energy over the whole frequency range, for a normal pulse with bandwidth of only 1 Mhz ,then only 0.025% of jamming power will get into radar receiver. For a compressed pulse with 1 Ghz bandwidth ,about 25% of jamming power will get into radar receiver. That quite a big different of around 30dB


This is handled with the matched filter or pulse compressor which basically amplifies the received radar signal while noise level isn't amplified that much as it doesn't match the filter. Certainly barrage noise jamming will have some effect on pulse compression radars, but far less so than on radars without it. How much exactly depends on how the pulse compression is done and other properties of radar. Usually modern jammers will do jamming against far narrower bandwidths at any one time to get enough jamming power through. Still modern radars can burn through such jamming at pretty significant distances away against regular RCS targets. This is why more elaborate jamming methods are used, although noise jamming certainly has its place.

garrya wrote:
hornetfinn wrote:Yes, phase combinations are very limited. In binary phase codes it's as name suggest binary with two states. Polyphase codes can have more states, but it's still limited to fairly small number of states. Anyway, in phase coding a long pulse is divided to extremely short subpulses which are coded by varying the phase.Using phase modulation system it's possible to transmit more information than using frequency modulation as it allows more efficient use of signal bandwidth to transmit information

According to this http://www.radartutorial.eu/08.transmit ... on.en.html phase coded pulse compression seem to have very low compression ratio ,maximum value is only 13 ( or is that only for Baker code ? )


That's true only for Barker codes and I'm pretty sure no modern military radar uses these codes only. Being at best being 13 bits long and having only handful of codes makes the Barker code predictable and susceptible to jamming. Barker codes are so called optimum codes (not all of them are, but still) as they provide low sidelobes which are all equal in magnitude. There is nothing preventing using longer codes with slightly reduced sidelobe performance.

Please read this, it's the best article I could quickly find: http://dspace.mit.edu/bitstream/handle/ ... sequence=2

Another good read: http://www.acfr.usyd.edu.au/pdfs/traini ... lution.pdf

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 28 Oct 2016, 11:20
by hornetfinn
popcorn wrote:I guess the jamming is part of the story. Also being able to detect and exploit holes in the IADS.


That too, definitely. IMO it's like this:

1. F-35 is far more capable of detecting and precisely locating threat systems than any fighter before it
2. With this knowledge it can position and orient itself for maximum effect
3. With very high gain and high power antenna of the AN/APG-81 it can put highly effective jamming against engagment and fire control radars. Even using very small part of the APG-81 for jamming purposes will beat legacy self-protection jammers easily. Using large part of APG-81 for jamming will mean jamming capability almost equal to dedicated legacy jamming platforms (in higher frequencies at least).
4. VLO stealth allows it to get much closer to threat systems to put even more effective jamming against them to protect following 4th gen aircraft

Combination of all this is make F-35 pretty much unparalleled EW system ever. Even if some dedicated jammer aircraft might have even more powerful EW systems, they will have to stay much further away from threat systems as they themselves can easily be detected and targeted because even the most powerful EW systems can't overpower radar systems if RCS is high. Another huge advantage is that they can work as one coherent force and there will be a lot of F-35s around. I don't think many people understand how big effect all this will have on combat performance, especially when 4th gen aircraft are used alongside F-35s.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 28 Oct 2016, 14:25
by garrya
thanks alot for those informative links hornet, i will look at it and added useful info to my blog :mrgreen:

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 04 Nov 2016, 16:29
by spazsinbad
DARPA Ups Funding For Autonomous Electronic Warfare Work
03 Nov 2016 Colin Clark

"WASHINGTON: DARPA is taking another step toward building autonomous electronic warfare systems with a small contract award to BAE Systems.

Artificial intelligence and autonomy loom large in the Pentagon these days. And electronic warfare, much more quietly, dominates a great deal of thinking across the services these days after we’ve watched how the Russians operate against Ukraine and in Syria. So DARPA’s additional $13.3 million award announced today is worth noting.

Why does all this matter? One of the biggest challenges facing the F-35 program, for example, is the creation of a huge digital threat library (known as mission data files) for the airplane. It includes electronic spectrum information for a wide array of emitters — radar, radio and other sources....

...Bear in mind that much of EW work and related funding is highly classified, so what we see in public is just the tip of the electromagnetic iceberg." [BEST READ IT ALL AT THE URL]

GRAPHIC: "Conceptual graphic of DARPA Adaptive Radar Countermeasures (ARC) by BAE" http://breakingdefense.com/wp-content/u ... by-BAE.jpg


Source: http://breakingdefense.com/2016/11/darp ... fare-work/

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 09 Jan 2018, 11:58
by spazsinbad
HASC EW Expert Bacon: US ‘Not Prepared’ For Electronic Warfare Vs. Russia, China
08 Jan 2018 Sydney J. Freedberg Jr.

"...Russia & China
The high-end fight, of course, will be even harder. Traditional “stand-off” jammers aren’t stealth aircraft, so they rely on keeping their distance from anti-aircraft threats. That keeps getting harder and more dangerous as Russian-made surface-to-air missiles grow in range, with the latest round for the S-400 Triumpf system claiming a reach of 250 miles. The old Air Force Compass Call and the new EC-X, the old Navy Prowler and the new Growler, are all at risk. (So are other support planes such as AWACS).

That’s why the US needs “penetrating” jammers, Bacon [Rep. Don Bacon, a retired one-star general] said: stealth aircraft that are harder – though hardly impossible – to target and which can slip into enemy airspace to conduct electronic warfare at shorter ranges.

Would that mean the F-35 Joint Strike Fighter, which has much-touted but publicly unknown EW capabilities? Perhaps, Bacon told me, emphasizing he had to keep far away from any classified materiel. In the near-term, though, he is most interested in the F-35’s potential as “a giant sensor package,” stealthily conducting reconnaissance ahead of the main force.

No one aircraft will solve the problem, he emphasized: The US needs a “balanced force” of both manned EW aircraft and drones, both stealthy and non-stealthy. “Stealth is not the silver bullet by itself; stealth has to be surrounded with EW support,” Bacon said. (Stealth reduces radar signature but can’t eliminate it). “Before you get a B-2 or B-21 over the target, it’s going to take some EW support as well, in the high-end fight.”..."

Source: https://breakingdefense.com/2018/01/has ... sia-china/

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 09 Jan 2018, 21:12
by alloycowboy
Electronic Warfare: The Part Of The F-35 Fighter Story You Haven't Heard

https://www.forbes.com/sites/lorenthomp ... 2c049068cc

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 09 Jan 2018, 21:38
by steve2267
alloycowboy wrote:Electronic Warfare: The Part Of The F-35 Fighter Story You Haven't Heard

https://www.forbes.com/sites/lorenthomp ... 2c049068cc


Article is very positive / complimentary of the F-35's EW capabilities and provides good, generalized descriptions of those capabilities in terms the average layman can grasp.

I did like this part in particular:

Three distinctly different variants of the plane will supply each service with performance features tailored to their unique requirements, [i]in an exceptionally agile and versatile aircraft designed to be far more survivable than those that came before.[/i]


Some are now starting to publicly recognize and describe the aircraft as agile. Hurrah!

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 09 Jan 2018, 21:44
by spazsinbad
Some quotes I like from article above by LOREN THOMPSON (LORD OF THE EVIL F-35 PUBLIC RELATIONS EMPIRE!) :devil: :doh:
"...The F-35's electronic-warfare system is built by BAE Systems, Inc., the U.S. subsidiary of Britain's biggest defense contractor. Like F-35 prime contractor Lockheed Martin, BAE Systems is a longtime contributor to my think tank and consulting client. But the company is so reserved in discussing features of the system that I didn't bother to solicit comments for this story. Fortunately, there are a few other sources one can turn to for a general grasp of how efectively F-35 maneuvers in the electromagnetic realm.

Unlike legacy tactical aircraft that had "federated" electronic-warfare systems, the F-35 architecture is highly integrated. Radio-frequency and electro-optical receivers are embedded around the edge of the airframe to provide continuous sensing of hostile emitters in every direction, with collections from all sensors fused through a central computer before being displayed on the visor of the pilot's helmet. The system also merges information from of-board sensors to provide a comprehensive picture of the local electronic environment.

F-35 is the first fighter that integrates threat data from across the relevant segments of the spectrum before displaying it to the pilot. That reduces the time required to respond to dangers while also easing pressure on the pilot. In fact, if the pilot is preoccupied with other facets of the mission, the EW system will automatically generate the optimum solution to a threat, whether that means jamming a radar, releasing chaff to confuse it, or launching false targets (usually hightech flares) to draw away heat-seeking missiles....

...Because the F-35's EW architecture is fully digitized, it weighs less, needs less space, and requires less power than legacy technology. However, the F-35 provides much greater electrical power for electronic applications than last-generation aircraft, enabling it to collect information and generate efects over larger areas. The radar is designed to generate highly directional signals for jamming so that emitters in specific locations can be disrupted without causing collateral efects elsewhere in the battlespace...."

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 21 Jan 2018, 01:25
by michaelemouse
About VLO jammers: I get that having VLO would be useful to sneak into a stand-in jammer position but once you're emitting the jamming signal, are you're likely to give away at least your direction to that jammed radar?

One of the ways LPI radar stays undetected is by having very low power signal and AESA can be excellent at focusing power in a pencil beam to have high effective radiated power but if you're jamming an enemy radar, there still has to be a significant amount of power that reaches the victim radar from your position.

Hasn't there been a trend for stand-in jammers to overwhelmingly be drones or munitions?

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 21 Jan 2018, 02:11
by jetblast16
The radar is designed to generate highly directional signals for jamming so that emitters in specific locations can be disrupted without causing collateral efects elsewhere in the battlespace....


Directed Energy 8)

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 21 Jan 2018, 02:58
by sferrin
spazsinbad wrote:Some quotes I like from article above by LOREN THOMPSON (LORD OF THE EVIL F-35 PUBLIC RELATIONS EMPIRE!) :devil: :doh:


This is the same guy launching all kinds of baseless innuendo against SpaceX with regards to the Zuma launch. (SpaceX is in the process of leaving ULA in the dust.) I've come to the conclusion he pretty much says what they pay him to say. (Boeing and LM -ULA partners- both contribute to his think tank.)

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 31 Oct 2018, 15:47
by white_lightning35
I didn't know where to put this so I chose here.

https://www.forbes.com/sites/lorenthomp ... 047b0a3ec8

Thoughts?

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 31 Oct 2018, 16:14
by SpudmanWP
Sorry, but no.

His reasoning for not re-competing the ESM was weak. Given the source, my first thought was "Is BAE sponsoring him now"?

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 31 Oct 2018, 16:31
by steve2267
All of Loren Thompson's arguments would seem to apply to DAS as well, yet LM is switching DAS to Raytheon.

I don't think I buy Thompson's arguments at their face, but these sorts of decisions do represent risk. LM has developed a great aircraft in the F-35; I hope they don't muck it up now.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 31 Oct 2018, 16:58
by SpudmanWP
Worst-Case they go back to BAE

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 31 Oct 2018, 20:04
by marsavian
Yes, competition is good even if they only get a price cut out of it. A fact I was not aware of ...

the F-35′s electronic-warfare system is so capable that it reportedly has been selected for use on the Air Force’s next-generation B-21 bomber, a strike aircraft that is designed to penetrate the most densely defended airspace in the world. So we know the system must work pretty darned well.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 31 Oct 2018, 20:18
by lamoey
SpudmanWP wrote:Sorry, but no.

His reasoning for not re-competing the ESM was weak. Given the source, my first thought was "Is BAE sponsoring him now"?


From the article quoted by Spaz above:
Like F-35 prime contractor Lockheed Martin, BAE Systems is a longtime contributor to my think tank and consulting client

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 28 Nov 2018, 01:10
by spazsinbad
Commercial Advances Are Reshaping Electronic Warfare
27 Nov 2018 Graham Warwick

Lockheed Martin F-35
"BAE Systems’ ASQ-239 digital offensive and defensive EW system on the F-35 Joint Strike Fighter provides integrated all-aspect, broadband radar warning and geolocation, targeting support and radiofrequency and infrared countermeasures. According to Lockheed Martin, the system has “10 times the effective radiated power of any legacy fighter” for standoff and stand-in jamming and is designed to operate without interfering with the RWR or the Northrop Grumman APG-81 AESA radar that has electronic attack capabilities, including generating false targets, high-power jamming and network attack."

Source: http://aviationweek.com/electronic-warf ... ic-warfare

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 28 Nov 2018, 01:22
by popcorn
Let them compete.

Re: BAE Systems Inches Out In Public On Electronic Warfare

Unread postPosted: 02 Feb 2019, 02:00
by operaaperta
New EW system from Lot 11. Have there been any details?

“Sustaining multiple configurations of fielded aircraft (i.e., Block 2B, Block 3F, and the new electronic warfare (EW) system in Lot 11 and later aircraft) while managing a....”

Source- DOT&E Report p26