The AAD missile of Indian BMD uses a Ka-band seeker. The development of the seeker was a major challenge, as unlike other seekers developed so far a BMD interceptor's RF seeker requires very high update rates. A multi-agency task force comripising of Sameer, ECIL, DRDO, BARC, was formed to develope this unique seeker .
It is a three channel mono pulse airborne radar with a waveguide slotted planar antenna . Range and angle information are updated every 50-100 ms .
The seeker has a detection range of 20 km for a 0.1 sq m RCS target .
This seeker is an engineering marvel by itself.
The initial variant of Swordfish LRTR had a 600 km detection range as illustrated in this slide. The seeker brings down the designation error from 600 metre of the initial target tracking data passed on by the radar to just 20 metres thus enabling an almost direct hit .
ANew updated variant of this seeker with greater ranges has already been developed and is in active service.
This is the newer enhanced AAD ver 2. It's longer than the original AAD which debuted way back in the earlier decade and also sports canards just behind the nose radome for improved controllability. The AAD can be termed as an almost hit to kill interceptor . The miss distance if any is just a few metre.