India's AESA radar development

[dbc]

The swedes and maybe EADS are banking on a mechanical device known as "swashplate" ( which can be very crudely described as a plate moving in all three planes ) on which to put their TR ( transmitter reciever ) modules ( the heart of aesa )

This rotating aesa radar can scan a total angle of 200 degrees out of 360 while normal aesa ( fighter version) can only scan upto 120. I guess this is what dbc meant by advantage of rotating aesa. As to whether it will work as promised, that remains to be seen!

check following links if you want to know more.

swashplate



swedish aesa

The trade off of mounting the antenna on a gimbal or swashplate is compromised LO or increased RCS. One of the biggest RCS contributors is the radar antenna, the amount of scattering caused by the antenna can be reduced by canting the antenna outward by 15 degrees.

The idea is to scatter the incident electromagnetic waves away from probing radars. If the AESA is mounted on a gimbal and mechanically steered as shown in the video below then the antenna will present a 90 degree angle to enemy radars.

Contrast the above image of the Zhuk-AE AESA with the below video of the IRBIS E Radar mounted on a gimbal to understand the difference.

RCS of an Antenna
For the case of an antenna the total RCS can be divided into two separate components as Structural Mode RCS and Antenna Mode RCS. The two components of the RCS relates to the two scattering phenomena that takes place at the antenna. When an electromagnetic signal falls on an antenna surface, some part of the electromagnetic energy is scattered back to the space. This is called structural mode scattering. The remaining part of the energy is absorbed due to the antenna effect. Some part of the absorbed energy is again scattered back into the space due to the impedance mismatches, called antenna mode scattering.

 

[ganimi kawa]

The trade off of mounting the antenna on a gimbal or swashplate is compromised LO or increased RCS. One of the biggest RCS contributors is the radar antenna, the amount of scattering caused by the antenna can be reduced by canting the antenna outward by 15 degrees.

This is correct for gimbal mounted antenna like the irbis ( but it's the flankers, who cares about RCS? )

But the advantage of canting the antenna is retained by swashplate mount. In fact 40 degree cant angle is said to be optimum for swashplate .

So theorotically you get a radar with better performance and equal if not less rcs as compared to non moving aesa!

The swashplate mechanism

Swashplate mounted aesa concept.

 

[Devianz]

The swedes and maybe EADS are banking on a mechanical device known as "swashplate" ( which can be very crudely described as a plate moving in all three planes ) on which to put their TR ( transmitter reciever ) modules ( the heart of aesa )

I know about swashplate AESA.. Its not similar to a fully 360 degree rotating AESA radar for AWACS.

 

[Dark Angel]

These are the first steps in indigenisation so kurdos to all the hard work

JAI HO

 

[Break the Silence]

Well, a silly qus. from my side! Can anybody tell me the difference bw AESA and Pesa???

 

[ganimi kawa]

I know about swashplate AESA.. Its not similar to a fully 360 degree rotating AESA radar for AWACS.

Well that is pretty obvious, my friend ! I have never said anything like that. Anyway , will you please explain why you are so interested in fully 360 degree rotating AESA? What significant advantage will it have over a traingular arrangement like the phalcon?
regards

 

[sudhir007]

is it possible that we can use Swordfish radar which DRDO developing for BDM on any plane and use it. what kind of this radar is it AESA or PESA. I dnt know much more about radar.

Swordfish Long Range Tracking Radar - Wikipedia, the free encyclopedia

 

[Devianz]

Well that is pretty obvious, my friend ! I have never said anything like that. Anyway , will you please explain why you are so interested in fully 360 degree rotating AESA? What significant advantage will it have over a traingular arrangement like the phalcon?
regards

Just curious to know about the different types available.
As far as advantages of rotating AESA... I don't know. Maybe they can be more powerful as the antenna size can be much larger than that of a triangular configuration. DBC can answer that question.

 

[Devianz]

is it possible that we can use Swordfish radar which DRDO developing for BDM on any plane and use it. what kind of this radar is it AESA or PESA. I dnt know much more about radar.

No, it cannot be used on any aircraft. It's a ground based radar.
Swordfish is a derivative of Israeli EL/M-2080 Green Pine AESA radar.

 

[ganimi kawa]

Just curious to know about the different types available.
As far as advantages of rotating AESA... I don't know. Maybe they can be more powerful as the antenna size can be much larger than that of a triangular configuration. DBC can answer that question.

AFAIK , that is not the case .

As dbc has already told E 2d is the only platform with rotating AESA . Apart form that most of the future awacs designs are using triangular arrangement.

E 2d designers may have opted for this configuration to reduce cooling requirement ( achilles heel of any aesa), as the aircraft is small.

Also, each side of the triangle scans a 120 degree area with max accuracy beyond which the range and accuracy diminishes. Mechanically reorienting the antenna may reduce this problem. Though, I am not sure whether this is a valid advantage given the advances in this field

 

[anathema]

is it possible that we can use Swordfish radar which DRDO developing for BDM on any plane and use it. what kind of this radar is it AESA or PESA. I dnt know much more about radar.

Swordfish Long Range Tracking Radar - Wikipedia, the free encyclopedia

We cannot. Size would be a problem - green pine on which swordfish is based is said to be 30ft wide and 10ft high ! Further powering requirements would be a problem also. However the knowledge that we got based on the development (read customize) the green pine radar will no doubt be useful in creating our own AESA components for AWECS.

 

[chauism]

Ohh, my mistake... so are there any AWACS radome that rotates?

E-2, E-3, Tu-126, and A-50.

The reason for those early radome to rotate is because it uses mechanically scanned radar, thus need to rotate to achieve 360 degree coverage. For modern phase array radars, it is not a problem. Some with 3 or 4 fixed panels of PAR, it can cover 360 degree without any moving parts.

 

[anathema]

For those interested in Swordfish radar -- video of Green pine radar below.

 

[ganimi kawa]

We cannot. Size would be a problem - green pine on which swordfish is based is said to be 30ft wide and 10ft high ! Further powering requirements would be a problem also. However the knowledge that we got based on the development (read customize) the green pine radar will no doubt be useful in creating our own AESA components for AWECS.

Power, cooling requirements and size make this concept non feasible.

About the highlighted part ; the green pine is a L band radar.An interesting fact is there were two types of TR modules proposed for indian aesa for awacs; a L band version and a S band version. Out of these two the S band version has been selected and not the L band one.

So, while there is no doubt that we learned many things about aesa from the green pine; there is a fair bit of home grown effort!

 

[dbc]

AFAIK , that is not the case .

As dbc has already told E 2d is the only platform with rotating AESA . Apart form that most of the future awacs designs are using triangular arrangement.

E 2d designers may have opted for this configuration to reduce cooling requirement ( achilles heel of any aesa), as the aircraft is small.

The E2 D design decision was influenced by the need to maintain commonality with older E2 C's enabling an upgrade to AESA if desired.