IDN TAKE: POUNDING THE ENEMY

[Zarvan]

Bharat Electronics Limited's SWATHI Weapon Location Radar

It was the Kargil war that exposed a chink in the armour of the Indian armed forces — the lack of a weapon locating radar. The Pakistani forces, armed with AN/TPQ-36 Firefinder Weapon Locating System, were able to accurately pin down and destroy the Indian artillery batteries and shell-firing guns. It was during this time that the Army struck upon the idea of using a derivative of the Rajendra radar in the artillery locating role. During the tests for a missile system at Chandipur, DRDO scientists noticed that the Rajendra Radar was able to detect and track artillery shells being test fired at a nearby range. This led to the development of the indigenous Weapon Locating Radar.

Lead Developer
Bharat Electronics Limited (BEL) is a pioneer in India in the field of radars and has, in collaboration with DRDO labs, been designing and manufacturing land-based, airborne and ship borne radars for defence and civilian applications since 1964.

Some of the important radar projects executed by BEL over the years are 2D Low-Level Surveillance Radar (INDRA II), 2D Surveillance Radar Element (SRE), Flycatcher Radar, Battle Field Surveillance Radar Short Range (BFSR-SR), Battle Field Surveillance Radar Medium Range (BFSRMR), 3D Surveillance Radar (Rohini), 3-D Tactical Control Radar, Flight Level Radar and Troop Level Radar for Akash Missile System and Doppler Weather Radar Mk–II for ISRO and the MET department. New generation 3D and 4D Radars with AESA technology are in the pipeline.

BEL has added another feather to its cap with the development and successful trials of Weapon Locating Radar (WLR), which is a field artillery radar system capable of locating enemy artillery batteries or shell-firing guns, mortars and rocket launchers with great precision and guiding own artillery fire to neutralise the enemy targets. The radar system is configured on two TATRA vehicles: Radar Vehicle and Power Source-cum-Band Interrupt Tactical Emitter (BITE) Vehicle. The system has been developed jointly by the Military Radar Strategic Business Unit of BEL’s Bangalore Complex and Electronics & Radar Development Establishment (LRDE), a DRDO laboratory based out of Bangalore.

BEL, along with technical support from LRDE, initiated the indigenous development of WLR in May 2002 and completed realisation of the engineered model in 2010, incorporating new technologies/techniques like flexible waveforms through Digital Pulse Compression, improving the average power of transmitter for higher (5%) duty cycle, software improvements for better clutter handling and incorporation of Power PC-based Programmable Signal Processing Unit (PSPU) and weight reduction. The system has cleared all the five phases of trials, viz., actual firing trials in the forward ranges of Pokhran and high altitudes of Sikkim.

How It Works?

The weapon locating radar (WLR) is a coherent, electronically scanned, C band, pulse Doppler, passive phased array radar designed to detect and track automatically incoming artillery rounds, mortar and rockets, and locate the hostile launchers. It can also track and observe the fall of short from friendly rounds, to provide fire corrections to counter the enemy fire. The radar can detect mortars, artillery guns and unguided rockets at various distance. Complex design of the radar array and algorithms permits the WLR to operate effectively even under severe clutter and high density fire environment. It can track several targets simultaneously.

The technological challenge in the design of WLR lied in achieving high probability of location for all calibers of projectiles having very low radar cross-section (RCS) both for high and low angle fire. Energy-time management has been optimised to address the challenges to meet the stringent location accuracies in absolute grid coordinates. An adaptive radar resource scheduling feature has enhanced the efficiency and reliability of the radar.

The radar can scan hostile targets in one quadrant. The array can electronically scan from its referenced mean bearing. The whole array can be rotated on either side by 135deg to achieve 360deg coverage from a given position within 30 s, to quickly change the scanning sector in response to potential threats.

On detecting an incoming hostile round, the radar automatically acquires and classifies the threat and
initiates a track sequence while it continues to search for new targets. Algorithms for trajectory computations use environmental factors, along with trajectory and track data, for estimating both launch and impact points to the desired accuracy. The fence concept of beam positioning, and grazing the radar air space, makes it impregnable for hostile projectiles without detection.

The computed launch point can be reported by the radar operator to the friendly artillery to direct counter-battery fire towards enemy artillery. Tracking of the target is achieved with mono-pulse signals and the in built pulse compression features improve the radar’s low probability of interception (LPI). Its processors perform real-time signal processing on the acquired data. An adaptive algorithm based on modified version of the Runge-Kutta method and incorporation of constant false alarm rate (CFAR) techniques aid in the accuracy of target detection. An operator can select the suitable CFAR technique for maximising accuracy of track/information. The data is processed on the state-of-the-art programmable digital signal processor using modified extended Kalman filters (one with size six states and another with seven states). Moving target indication (MTI) aids to improve the clutter rejection performance of the radar.

Target information is presented as a high resolution multi-mode colour display on the ruggedised power PCs in real time and can be overlaid on a digital map. The WLR can store a large size digital map for display purposes. Other artillery modes of displays include plan position indicator (PPI), RHI, etc. Up to 99 weapon locations can be tracked and stored at any time. The data can be automatically transmitted to a command centre and can be communicated with higher echelons. The radar data can also be displayed at a convenient remote screen to protect operators from any targeted attacks on the radar. Many radars can be networked together to operate in tandem to provide more information with enhanced accuracy.

WLR is configured into two vehicles named as, radar vehicle and power source-cum-BITE vehicle. The radar vehicle contains electronic and antenna shelter. The power source-cum-BITE vehicle contains two diesel generator sets and radar target simulator.

Delivery

BEL signed a contract for supplying of 30 WLR systems: 10 systems configured with high altitude kit for TATRA vehicles to the Indian Army on 30 December 2015. The First off Production Model (FoPM) of WLR came out in January 2016. Qualification Tests for improved subsystems and acceptance tests of all sub systems were completed, and firing trials successfully completed in mid-April 2016. The high altitude version of WLR and other versions for the plains have been manufactured and are under different stages of inspection and evaluation, production of the entire quantity of WLRs is undertaken and supplied as per the terms laid out by the Army.

The WLR was commissioned recently and put into operation along the volatile Pakistan border with devastating effect. Given a hand free by the government to pound enemy positions, the WLR has emerged as a significant weapon to silence the enemy guns.

Our Bureau

http://www.indiandefensenews.in/2017/08/idn-take-pounding-enemy-black-blue.html

 

[fsayed]