So, defense nuts recently nicked pics of a new variant (same but different) of Uttam Active Phased Array Radar. The tender was unusually information-rich (for a critical piece of technology slated to equip a combat aircraft). In case, that wasn't enough, LRDE proceeded to publish a screenshot of an MFD displaying tracking information. In the screenshots, Uttam appears to be keeping a 'FOX3-worthy' lock at a Tejas well beyond 140 kilometers and that's really something. Tejas easily has the lowest radar signature (for a non-stealth combat aircraft) in its class. Air-to-Air mode is where Uttam has exceeded expectations. It also has advanced NCTR and imaging capabilities.
Another thing, there is a misconception that Uttam's operating power is 3.6KW,_ okay, no, it's not. It's actually the heat dissipated during the operation or in other words - its liquid circulation has to remove 3.6 KW of heat out of the array. The actual radiating power is several times the heat dissipated. There are roughly 736 TRMs on the radar. To be accurate, it's actually the overall heat dissipation by the AAAU, the Receiver Exciter Processor (REP), and LRU. However, it appears to have been replaced by a more efficient cooling system as LRDE has been able to increase the number of TRMs to 992. For comparison, APG-80 that equips F-16B60 has ~1020 TRMs. Mind you though, the AAAU of Uttam is smaller than its PESA predecessor, the hybrid MMR (~600mm compared to 650mm of the PESA <MMR). An increased number of TRMs also means that it would be able to track a greater number of targets, it can already track 94 targets simultaneously.
Uttam uses good ol' dipoles as radiating elements, Not exactly what you expect from a radar designed in the late 2010s. Most of the contemporary radars are using Tapered Slot Antenna (TSA), e.g. RBE-2A on Rafale, ES-05 on Gripen-NG. That might prove to be a bottleneck in the radar performance, and it shows up as relatively narrow bandwidth - just 1 GHz. It's still a step up from N-011M BARS' 600 MHz but quite dismal compared to ~3 GHz bandwidth displayed by some of its contemporaries (APG-79, RBE-2A, etc). It's not like LRDE doesn't have the capability to developed UWB arrays. We have already seen VAAAU-16/32 in EW systems with over 4 GHz of operational bandwidth. Uttam's AAAU will need replacing if it is to keep up with the ever-evolving ECM environment.
Back to LRDE's habit of oversharing- They literally published almost every spec of their S-band TRM used in Arudhra 4D radar. I mean, guys, we know you made the radar. Take it easy. We just want better pics of the radars, not their specs or a blow-by-blow account of how you developed "something" in a journal.
While we are at other radars- there is something people confuse about- the L-STAR radar of Netra- There were two L-STAR radars, one from CABS and the other from LRDE. The range figure that is thrown around in the public domain is of the LRDE variant which is not what Netra currently has. LRDE lost to CABS design. In any case, CABS L-STAR is slightly larger than Saab's Erieye in terms of physical dimensions (8.2m vs 8m in length, Global Eye has a larger antenna). In test flights, Netra was able to track targets at 475km distance when operating in the extended-range mode. The tracks are likely to be airliners, even so, unlocking the true potential of the radar is one of the perks of having an indigenous design. The same goes for Uttam, looking forward to seeing what those "proprietary radar modes" developed by LRDE can do.
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| Netra long-range tracking capability |
Nice
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