The following is the IAF's S-125 upgrade program. Maybe you find this interesting.
A much welcome spinoff from the DRDO’s two-decade long R & D activities for the Akash-1 MR-SAM programme has now resulted in the development of an indigenous upgrade package for the Indian Air Force (IAF) remaining S-125 Pechora SAM systems that will extend their service-lives by another 12 years.
Restricted tenders worth US$272 million to upgrade 16 of the original 30 squadrons of the IAF’s S-125 Pechora SAM systems under the ‘Make in India’ programme were floated in May 2016 and were sent to TATA Power SED, Larsen & Toubro, Reliance Defence, Offset India Solutions, Amertec Systems Pvt Ltd, Bharat Dynamics Ltd (BDL), Bharat Electronics Ltd (BEL) and ECIL. While the V-601 missiles will be refurbished by BDL with the help of Russia’s OJSC Concern Almaz-Antey, the existing analogue fire-contol systems will be fully digitised by Indian OEMs, following which they will be integrated by BEL with the IAF’s IACCCS network.
BEL will also deliver the Rohini S-band 3-D CARs and related motorized command-and-control posts that will replace the older P-19 early-warning radars. Amertec Systems Pvt Ltd will supply the digitised LRUs and related ATEs for the upgraded SNR-125 pulse-Doppler tracking, fire-control and guidance radars. Deliveries will begin 42 months after contract signature.
However, this upgrade contract does not in any way postpone or stall the IAF’s plans for procuring 18 squadrons of Barak-8 MR-SAMs and LR-SAMs.
The Indian Air Force’s S-125 Neva (export name Pechora) uses the V-601 (or 5V27) missile has a length of 6.09 metres, a wingspan of 2.2 metres and a body diameter of 0.375 metres. This missile weighs 953kg at launch, and has a 70kg warhead containing 33kg of HE and 4,500 fragments. The minimum range is 3.5km, and the maximum is 25km. The intercept altitudes are between 100 metres and 18km. Radars used for the original S-125 included the following:
P-15M(2) TROPA 1RL13 C-band target acquisition radar, which comprised a single antenna on a tethered latticework mast. It was employed to improve low altitude coverage, but also to permit use of the radar in heavily forested terrain where the height of the foliage canopy exceeded the height of the antenna phase centre in the P-15. The P-19 DANUBE 1RL134 was the improved 2-D UHF follow-on to the P-15 with a range of improvements.
SNR-125 I/D-band tracking, fire-control and guidance radar, which uses a pair of fixed scanned trough antennas to generate flapping fan shaped beams, but the design is inherently SORO with a separate transmit antenna mounted between the characteristic chevron arrangement of trough antennas. Optical adjunct tracking using the 9Sh33A Karat 2 television telescope has been installed on later variants, initially the SNR-125M1. The antenna at the top of the turret is used for the low power missile FMCW uplink channels. The antennae functions are, respectively:
* UV-10: Transmit for target and missile tracking, Transmit/Receive for rangefinding, Transmit/Receive for initial target acquisition, Receive for clutter cancelling channel. The boom mounts a cluster of feed horns, including a rotating scanning feed, each producing unique mainlobes. The scanned acquisition beam mainlobe is 1° wide and swept through a 15° arc in elevation at 25 Hz, the mainlobe for target tracking, transmit and rangefinding receive is 10° wide.