View source for Swathi Weapon Locating Radar

{{Short description|Counter-battery radar}}
{{Use dmy dates|date=December 2020}}
{{Use Indian English|date=February 2016}}
{{Infobox Radar
| name              = Swathi Weapon Locating Radar
| image             = Weapon Locating Radar (Swathi) passes through the Rajpath during the full dress rehearsal for the Republic Day Parade-2018, in New Delhi on January 23, 2018.jpg
| caption           = Swathi Weapon Locating Radar at [[Republic Day (India)|Republic Day]] 2018
| country           = [[India]] 
| designer = [[Electronics and Radar Development Establishment]] ([[DRDO]])
| manufacturer      = [[Bharat Electronics Limited|Bharat Electronics]] 
| introdate         =   
| number            = 52 
| type              = Artillery Locating Radar
| frequency         = [[C band (IEEE)|C band]]<ref name="DRDO Brochure" />
| range= Artillery  → 2-30 km <br />Rockets → 4-80 km <ref name="The Indian Express">{{Cite web|url=https://indianexpress.com/article/cities/bangalore/bel-receives-order-army-procure-mountain-variant-of-weapon-locating-radar-7985127/|title=BEL receives order from Army to procure mountain variant of Weapon Locating Radar|publisher=The Indian Express|date=23 June 2022}}</ref><br />Mortars → 2-20 km<ref name="DRDO Brochure 2" />
| altitude          = <!--{{m to ft|X|addr=yes}}-->
| diameter          = <!--{{m to ft|X|addr=yes}}-->
| azimuth           = +/- 45° Electronic scan (Slewable Array)<ref name="DRDO Brochure" />
| elevation         = -5 to 75°<ref name="DRDO Brochure" />
| precision         = <!--±{{m to ft|X|addr=yes}}-->
| power             = 40 kW
| other names       = Swathi 
}}

The '''Swathi''' (''Very Beneficent'')<ref>{{cite web |url=http://www.sanskrit-lexicon.uni-koeln.de/scans/BURScan/2013/web/webtc1/index.php |title = BUR List}}</ref> [[weapon locating radar]] is a mobile [[artillery]]-locating, [[phased array radar]] developed by India.<ref>{{Cite web |url=http://pib.nic.in/newsite/erelease.aspx?relid=(Release%20ID%20:158803) |title=DRDO Hands Over its Developed Products to Indian Army |date=2 March 2017 |publisher=Press Information Bureau |access-date=2017-03-07 |archive-url=https://web.archive.org/web/20170308044833/http://pib.nic.in/newsite/erelease.aspx?relid=(Release%20ID%20:158803) |archive-date=8 March 2017 |url-status=live |id=Release ID :158803}}</ref> This [[counter-battery radar]] is designed to detect and track incoming artillery and rocket fire to determine the point of origin for [[counter-battery fire]].

The WLR has been jointly developed by the [[Electronics and Radar Development Establishment]] (LRDE), a lab of the [[Defence Research and Development Organisation]] (DRDO) and [[Bharat Electronics Limited]] (BEL). The sub-systems have been fabricated by BEL based on the DRDO designs and delivered to LRDE for integration.<ref>{{usurped|1=[https://web.archive.org/web/20080623214637/http://www.drdo.org/Electronics/wlr.html WLR Page]}} on DRDO website.</ref>

== Development ==

=== Background ===
The Indian army projected a requirement for fire-finding radars in the 1980s.<ref name="Freshnews">{{cite news | title = India acquires 12 contracted Weapon Locating Radars | url = http://www.freshnews.in/india-acquires-12-contracted-weapon-locating-radars-5721 | agency = Indo-Asian News Service | date = 2 May 2007 | access-date = 2008-07-25 | archive-url = https://web.archive.org/web/20170305042549/http://www.freshnews.in/india-acquires-12-contracted-weapon-locating-radars-5721 | archive-date = 5 March 2017 | url-status = live }}</ref> As early as 1989, the Indian Army evaluated the American [[AN/TPQ-36]] and [[AN/TPQ-37 Firefinder radar]]s. However, these radars were not allowed to be sold, and the procurement process was stopped by the [[Government of India|Indian Government]].<ref name="Luthra" /> In February 1995, a [[Request for Proposal]] (RFP) was issued to five companies for procurement of 4 WLRs. Only Hughes (now [[Raytheon]]) responded to the RFP. After trials, the radar was found to not meet the General Staff Quality Requirements (GSQRs) of the Indian Army, which were found to be too stringent, and the GSQRs were then relaxed. At the same time, it was decided to consider development of an indigenous WLR by India's primary defence contractor, [[DRDO]].<ref name="PSCoD-99" />

In September 1998, an RFP was issued for the urgent purchase of WLRs - AN/TPQ-36/37 from Hughes (USA), [[Thomson CSF]] (France) and ISKARA of ([[Ukraine]]). However, the American and French radars were withheld when sanctions were imposed after India's [[Pokhran-II]] nuclear weapon tests, and negotiations with the Ukrainian manufacturers came to no conclusion.<ref name="Samanta">{{cite news | author = Pranab Dhal Samanta | title = India can now procure weapon-locating radars |url=http://www.hinduonnet.com/2001/09/29/stories/02290005.htm | work = [[The Hindu]] | date = 29 September 2001 | access-date = 2008-07-25 | archive-url = https://web.archive.org/web/20041117012349/http://www.hinduonnet.com/2001/09/29/stories/02290005.htm | archive-date = 17 November 2004 | url-status = usurped }}</ref> Additionally, DRDO was not authorised to begin development of a WLR. These lacklustre efforts to obtain a WLR system were severely criticised by the Parliamentary Standing Committee on Defence.<ref name="PSCoD-99">[http://164.100.24.208/ls/committeeR/Defence/3.pdf Third Report of the Parliamentary Standing Committee on Defence] {{Webarchive|url=https://web.archive.org/web/20051130022909/http://164.100.24.208/ls/committeeR/Defence/3.pdf |date=30 November 2005 }} of the 13th [[Lok Sabha]] for the year 1999-2000 (PDF). pp 18-19. The Committee commented, ''"The Committee is seriously concerned by the degree of seeming casualness shown by the Defence Ministry in this regard. The Committee desires that the Government should take immediate steps to equip the Army with this Radar."''</ref>

Efforts to acquire such a system intensified after the [[Kargil War]] in 1999 where the [[Indian Army]] was severely disadvantaged by its lack of radar that could detect artillery fire. While the Pakistani forces were equipped with American AN/TPQ-36 Firefinder radars, India only had British [[Cymbeline (radar)|Cymbeline mortar detecting radars]], which were not suitable.<ref>{{cite news | author = Girja Shankar Kaura |title=Weapon-locating radars for India soon | url = http://www.tribuneindia.com/2002/20020219/main3.htm#2 | work = The Tribune |date=18 February 2002 |access-date = 2008-07-25 |archive-url=https://web.archive.org/web/20061211112624/http://www.tribuneindia.com/2002/20020219/main3.htm#2 | archive-date = 11 December 2006 | url-status = live }}</ref> Almost 80% of Indian casualties during the war resulted from enemy artillery fire, making such a radar critical.<ref name="Luthra" /><ref name="Samanta" />

=== Development ===
In 2002, the [[Ministry of Defence (India)|Ministry of Defence]] issued an RFP to five manufacturers. With the lifting of sanctions in late 2001, the US Government offered to sell the AN/TPQ-37 radar to India under their [[Foreign Military Sales]] (FMS) programme for {{Indian Rupee}}. 680&nbsp;million each.<ref name="PSCoD-02">[http://164.100.24.208/ls/committeeR/Defence/16.pdf Sixteenth Report of the Parliamentary Standing Committee on Defence] {{Webarchive|url=https://web.archive.org/web/20110518095137/http://164.100.24.208/ls/committeeR/Defence/16.pdf |date=18 May 2011 }} of the 13th [[Lok Sabha]] for the year 2002-03 (PDF). pp 23-24. The Committee commented, ''"The Committee are not satisfied with the reply of the Ministry of Defence that acquisition of Weapon Locating Radar(WLR) will take three years. Three years is a long period. In view of the grave security threat emanating from across the borders, immediate steps should be taken to procure WLR."''</ref> In July 2002, India placed a {{USD}} 200 million order for 12 AN/TPQ-37 Firefinder radars.<ref name="MoD 3 Jul">{{cite press release | title = Weapon Locating Radar | publisher = Press Information Bureau, [[Government of India|GoI]] | date = 30 July 2003 | url = http://pib.nic.in/archieve/lreleng/lyr2003/rjul2003/30072003/r3007200336.html | access-date = 2008-07-25 | archive-url = https://web.archive.org/web/20110605163058/http://pib.nic.in/archieve/lreleng/lyr2003/rjul2003/30072003/r3007200336.html | archive-date = 5 June 2011 | url-status = live }}</ref><ref>{{cite news | author-link = Raytheon | author = Raytheon Press Release | title = India Signs Agreement to Buy Firefinder Weapon Locating Radar | url = http://www.prnewswire.com/cgi-bin/micro_stories.pl?ACCT=683194&TICK=RTN4&STORY=/www/story/04-19-2002/0001710071&EDATE=Apr+19,+200  | agency = PR Newswire| date = 19 April 2002 | access-date = 2008-07-25 }}</ref> Initially, only 8 were ordered for {{USD}}140 million, but the order was later increased to 12.<ref name="Freshnews" /> The radars were integrated on [[BEML Limited]] manufactured [[Tatra (company)|Tatra truck]] platforms.<ref name="Luthra" /> Delivery of all 12 radars was completed in May 2007.<ref name="Freshnews" /> Concept design work on the WLR also accelerated in the aftermath of the Kargil War.

The WLR project was officially sanctioned in April 2002, with a sanctioned amount of {{Indian Rupee}} 200&nbsp;million and an estimated completion time of 40 months.<ref>{{cite news | title = Manufacturing of Weapon Locating Radar | url = http://mod.nic.in/samachar/june15-02/html/ch8.htm | work = Sainik Samachar | publisher = [[Ministry of Defence (India)]] | date = 15 June 2002 | access-date = 2008-07-25 | archive-url = https://web.archive.org/web/20090410193513/http://mod.nic.in/Samachar/june15-02/html/ch8.htm | archive-date = 10 April 2009 | url-status = live }}.</ref> The first working prototype was to be ready by April 2004. The final project cost was {{USD}} 49 million.{{Citation needed|date=July 2008}} In January 2003, an intent for procurement of 28 WLRs was placed with BEL.<ref name="MoD 3 Jul" />

A basic prototype of the WLR was first unveiled at [[Aero India]]-2003.<ref name="ACIG AI-03">{{usurped|1=[https://web.archive.org/web/20141010180852/http://www.acig.org/artman/publish/article_227.shtml Picture of the WLR]}} from [[Aero India]]-2003.</ref> The WLR was showcased at the Republic Day Parade in 2007.<ref>{{cite press release |title=Republic Day 2007 - A curtain raiser |date=25 January 2007 |publisher=Press Information Bureau, [[Government of India|GoI]] |url=http://pib.nic.in/release/rel_print_page1.asp?relid=24362 |access-date=2008-07-25 |url-status=live |archive-url=https://web.archive.org/web/20110605163201/http://pib.nic.in/release/rel_print_page1.asp?relid=24362 |archive-date=5 June 2011}}</ref> User trials of the WLR began in 2005. The Army also used WLRs to further their "[[shoot-and-scoot]]" doctrine using self-propelled guns and artillery to loosen up defence before an offensive onslaught into hostile territory.<ref name="What is India" /> By mid-2006, the WLR was in advanced user acceptance trials and the radar was stated to be ready for production.<ref>{{cite news |date=20 December 2005 |title=India developing weapon locating radar |publisher=BBC Monitoring South Asia |agency=PTI |quote="It (weapon locating radar) is in the final stage of evaluation. Once evaluation is complete, we will deliver it to armed forces," chairman and managing director of BEL, Y Gopala Rao, told reporters.}}</ref><ref>{{cite news |date=21 December 2005 |title=Weapon locating radar in final evaluation stage |url=http://www.hindu.com/2005/12/21/stories/2005122125480400.htm |url-status=dead |archive-url=https://web.archive.org/web/20090210164521/http://hindu.com/2005/12/21/stories/2005122125480400.htm |archive-date=10 February 2009 |access-date=2008-07-25 |work=[[The Hindu]] |quote=Electronics and Radar Development Establishment (LRDE) and Bharat Electronics Limited are in the process of developing a weapon-locating radar, similar to the phased array Rajendra radar system, customised for airborne and ground defence systems.}}</ref>

After user trials by the Indian Army in severe electronic clutter and "high density fire environment", in June 2008, the WLR was accepted by the [[Indian Army]].<ref name="Luthra" /> 28 units are on order, and are being manufactured by BEL. A large number of components will be sourced from the private sector, including some [[commercial off-the-shelf]] (COTS) components from the international market.<ref name="Luthra" /> The WLR will eventually service the Army's requirement for 40-50 systems.<ref>{{cite news |date=15 January 2004 |title=India to test long-range Agni missile next year |url=http://www.indianembassy.org/i_digest/2004/jan_15/agni.htm |url-status=dead |archive-url=https://web.archive.org/web/20041215204829/http://www.indianembassy.org/i_digest/2004/jan_15/agni.htm |archive-date=15 December 2004 |access-date=2008-01-23 |work=India Digest |publisher=[[Embassy of India in Washington]] |quote=DRDO's weapon-locating radar would be in competition to fill the Indian Army's need for 40-50 such systems.}}</ref> Further improved versions of the WLR are being planned and designed,<ref name="Luthra" /> including longer range versions, as well as more compact variants for better operation and navigation over mountainous terrains.

==Design==
The WLR is similar to the [[AN/TPQ-37 Firefinder radar|AN/TPQ-37 radar]] in design and performance<ref>{{cite news|title=India develops weapon-locating radar |url=http://news.indiamart.com/news-analysis/india-develops-weapo-8437.html |publisher=PIB Press Release |date=13 December 2004 |access-date=2008-07-25 |quote=India has developed a weapon-locating radar (WLR) similar to the AN/TPQ-37 of the US at a cost of {{Indian Rupee}}.260 million ($49 million), Defence Minister Pranab Mukherjee told the Lok Sabha 9 Dec. |url-status=dead |archive-url=https://web.archive.org/web/20061029115250/http://news.indiamart.com/news-analysis/india-develops-weapo-8437.html |archive-date=29 October 2006}}</ref> but is reportedly more user friendly.<ref>[http://www.forceindia.net/interview3.asp "Once we Partner with World Class Companies, we May have to Upgrade our Capabilities"] {{Webarchive|url=https://web.archive.org/web/20080803165545/http://www.forceindia.net/interview3.asp |date=3 August 2008 }}, An Interview with H.S. Bhadoria, Director, Bangalore Complex, Bharat Electronics Ltd., ''Force Magazine''. Retrieved 28 July 2008</ref> It is a [[passive electronically scanned array]] radar, derived from the [[Rajendra Radar]] (which is the fire control radar for the [[Akash missile]] system).<ref name="DRDO Brochure" /> During tests of the [[Akash missile]] at Chandipur, engineers noticed the Rajendra radar was able to detect and track [[artillery]] shells being test fired at a nearby range.<ref name="Luthra">{{cite news | first = Gulshan | last = Luthra | title = Indian Army acquiring 28 indigenous Weapon Locating Radars | url = http://www.indiastrategic.in/topstories130.htm | work = India Strategic Magazine | location = [[New Delhi]] | date = July 2008 | access-date = 2008-07-28 | archive-url = https://web.archive.org/web/20110721162415/http://www.indiastrategic.in/topstories130.htm | archive-date = 21 July 2011 | url-status = live }}</ref><ref name="What is India">{{cite news | title = BEL Weapon Locating Radars | url = http://www.whatisindia.com/stories/2006/12/wis_ds_20061214_bel_weapon_locating_radars.html | publisher = What Is India News Service | date = December 2006 | access-date = 2008-07-25 | quote = The new radar is based on the Rajendra-phased radar system that is already deployed in the Indian armed forces after engineers accidentally noticed during an anti-missile Akash missile test, that the Rajendra system could detect and track artillery shells. | archive-url = https://web.archive.org/web/20080904222036/http://www.whatisindia.com/stories/2006/12/wis_ds_20061214_bel_weapon_locating_radars.html | archive-date = 4 September 2008 | url-status = live }}</ref> Based on this observation, LRDE scientists were able to adapt the Rajendra Array into the WLR.

The WLR Array is an electronically steered radar, meaning the radar antenna does not move while in operation. The radar can electronically scan a +/-45° range of [[azimuth]]s for incoming rocket, artillery and mortar fire. The radar antenna is slewable up to +/-135° within 30 seconds, which gives the WLR the ability to quickly change its scanning sector, and provides it 360° scan capability. The coherent [[travelling-wave tube]] (TWT) based transmitter of the WLR emits 40&nbsp; kilowatts of power.<ref name="DRDO Brochure" />

Tracking of the target is done with [[monopulse]] signals with [[pulse compression]], which improves the radar's range accuracy. The radar processors conduct [[Real-time computing|real-time signal processing]] of the received signals. The weapon locating algorithm is an [[adaptive algorithm]] based on a modified version of the [[Runge-Kutta method]], and uses [[constant false alarm rate]] (CFAR) techniques to detect the target accurately. The operator can choose the CFAR technique to be used to maximise the accuracy of information. The data is processed on a programmable [[digital signal processor]] using a modified extended [[Kalman filter]], with two filters - one with 6 states, and another with 7 states. Clutter rejection is achieved through a [[moving target indicator]] (MTI), Airborne MTI (AMTI) and [[fast Fourier transform|Fast Fourier Transform]] (FFT).<ref name="DRDO Brochure" />

Information is displayed on [[Rugged computer|ruggedised]] power PCs on a high resolution multi-mode colour display. The data is displayed in real-time and can be overlaid on a 3D digital map. The WLR can store a 100&nbsp;km x 100&nbsp;km size digital map for display at any time. Other modes include [[plan position indicator]] (PPI) display, RHI displays, etc.<ref name="DRDO Brochure 2" /> Up to 99&nbsp;weapon locations can be stored and tracked at any time and can be transmitted to the command centre.<ref name="DRDO Brochure" />

==Operation==
The WLR is designed to detect and track incoming artillery rounds, mortar and rockets and locate their launchers. In its secondary role, it can also track and observe the fall of shot from friendly guns and provide fire corrections to counter-battery fire.<ref name="DRDO Brochure">[http://media.bharat-rakshak.com/AeroIndia2007/Brochures/WLR.jpg.html WLR Infoboard] {{Webarchive|url=https://web.archive.org/web/20090106034947/http://media.bharat-rakshak.com/AeroIndia2007/Brochures/WLR.jpg.html |date=6 January 2009 }} from DRDO, at [[Aero India]]-2007. Picture from [[Bharat Rakshak]].</ref>

The detection range for large caliber artillery rounds is up to 30&nbsp;km, and increases to 40&nbsp;km for unguided rockets. The robust design of the radar array and algorithms allows the WLR to effectively operate even in a high density fire environment, in severe [[radar clutter]] and interference (jamming) conditions. Up to 7 targets can be tracked simultaneously. The radar can track rounds fired at both low and high angles, and at all aspect angles - from behind or towards the radar, or at an oblique angle to the array. The WLR features adaptive radar resource scheduling to increase efficiency and reliability.<ref name="DRDO Brochure" />

At a given position, the radar can scan for targets in one quadrant, encompassing a 90° sector. The array can electronically scan up to +/-45° from its mean bearing. Additionally, for 360° coverage from a given position, the whole array can be rotated by 135°  on either side within 30 seconds to quickly change the scanning sector in response to threats.<ref name="DRDO Brochure" />

Upon detecting an incoming round, the automatically acquires and classifies the threat and initiates a track sequence, while continuing to search for new targets. The incoming round's trajectory is tracked, and a computer program analyses the track data and then extrapolates the round's point of origin. This calculated point of origin is then reported to the radar operator and can be stored up to 99 target locations with broad digital map displays thus allowing friendly artillery to direct counter-battery fire towards the enemy artillery.<ref name="DRDO Brochure" /><ref>{{Cite web |last=Strakes |first=Jason E. |title=Armenia's New Swathi Radar and Defense Imports from India: Eurasian Geostrategy or Technology Interface? - PONARS Eurasia |url=https://www.ponarseurasia.org/armenias-new-swathi-radar-and-defense-imports-from-india-eurasian-geostrategy-or-technology-interface/ |access-date=2022-03-15 |website=ponarseurasia.org |language=en-US}}</ref>

The WLR also allows for remote operation, and data-linking for better situational awareness at higher echelons of the command hierarchy. The data can be automatically transmitted to a command center, and can communicate with higher echelons. The radar data can also be displayed on a remote screen to protect operators from any targeted attacks on the radar. The operators can also remotely change the scanning sector.<ref name="DRDO Brochure" /> Many radars can be networked together to work in tandem and increase the accuracy and provide more information.

The Radar is designed to operate in harsh environments ranging from -20 to +55&nbsp;°C, in hot and humid conditions, and can be safely stored from -40 to +70&nbsp;°C. It can operate at high altitudes up to {{convert|16000|ft|m}}.<ref name="DRDO Brochure" /><ref name="DRDO Brochure 2">[http://media.bharat-rakshak.com/AeroIndia2007/Brochures/WLR_second_broc.jpg.html WLR Infoboard #2] {{Webarchive|url=https://web.archive.org/web/20090106024543/http://media.bharat-rakshak.com/AeroIndia2007/Brochures/WLR_second_broc.jpg.html |date=6 January 2009 }} from DRDO, at [[Aero India]]-2007. Picture from [[Bharat Rakshak]].</ref> Shock and vibration performance and resistance to [[electromagnetic interference]] (EMI)/[[electromagnetic compatibility]] (EMC) are according to international military standards. The WLR is designed for quick deployment and decamp, and can be ready for action within 30 minutes. In case of any incoming threats, the radar can be quickly moved out of the threat area.<ref name="DRDO Brochure" />

===Platform===
The WLR is configured on a wheeled [[Tatra (company)|Tatra]] truck platform. The trucks are manufactured by [[BEML]] in India under license.<ref name="Luthra" /> The WLR is designed to operate in a high-density fire environment and has all weather capability, high mobility and quick reaction time.<ref name="ACIG AI-03" /> The system is a two vehicle configuration, with the primary sensor, processors, displays and control unit on a single vehicle, and a separate power vehicle to power the radar. The radar data can also be displayed remotely.<ref name="DRDO Brochure" />

== Variants ==

* Swathi Mk1 (Plains) - based on [[Tatra (company)|Tatra]] [[Eight-wheel drive|8x8]] truck platform.
* Swathi Mk2 (Mountains) - based on [[Tatra (company)|Tatra]] [[Six-wheel drive|6x6]] truck platform.<ref name=":0" /> To be used in mountainous terrains with ease of mobility.<ref name=":1">{{Cite web |date=2022-06-23 |title=BEL receives order from Army to procure mountain variant of Weapon Locating Radar |url=https://indianexpress.com/article/cities/bangalore/bel-receives-order-army-procure-mountain-variant-of-weapon-locating-radar-7985127/ |url-status=live |archive-url=https://web.archive.org/web/20250122064718/https://indianexpress.com/article/cities/bangalore/bel-receives-order-army-procure-mountain-variant-of-weapon-locating-radar-7985127/ |archive-date=2025-01-22 |access-date=2025-01-22 |website=The Indian Express |language=en}}</ref>

==Orders==

* On 29 March 2015, the Defence Acquisition Council (DAC) cleared the procurement of 30 Swathi WLRs. The contract to [[Bharat Electronics]] was worth {{INRConvert|1605|c|lk=on|year=2015}}.<ref>{{Cite news |last=Pandit |first=Rajat |date=2015-03-29 |title=India to build two next-generation AWACS for Rs 5,113 crore |url=https://economictimes.indiatimes.com/news/politics-and-nation/india-to-build-two-next-generation-awacs-for-rs-5113-crore/articleshow/46731662.cms?from=mdr |access-date=2025-01-21 |work=The Economic Times |issn=0013-0389}}</ref> The [[Defence Research and Development Organisation]] (DRDO) officially handed over the WLR Swathi to the [[Indian Army]] on 2 March 2017 for service induction.<ref>{{cite news | title = DRDO radar handed over to Army; to bring down LoC artillery fire: Parrikar | url = http://www.oneindia.com/india/drdo-radar-handed-over-to-army-to-bring-down-loc-artillery-2363200.html | publisher = One India | date = 2 March 2017 | access-date = 2017-03-02 | archive-url = https://web.archive.org/web/20190210055048/https://www.oneindia.com/india/drdo-radar-handed-over-to-army-to-bring-down-loc-artillery-2363200.html | archive-date = 10 February 2019 | url-status = live }}</ref> All units delivered by 2022 and deployed along [[Line of Control]].<ref name=":1" />
* Armenia had conducted trials of similar systems offered by Russia and Poland, but they gave the final nod to the Indian system. The deal is for supplying four SWATHI weapon locating radars manufactured by [[Bharat Electronics Limited]] (BEL) at a cost of $40 million to Armenia. As per the agreement, India will supply four SWATHI weapon locating radars.<ref>{{cite web |title=India is stepping up as a security partner in the Caucasus |url=https://asia.nikkei.com/Opinion/India-is-stepping-up-as-a-security-partner-in-the-Caucasus}}</ref><ref>{{Cite web |title=India pips Russia, Poland to secure $40 million defence deal with Armenia |url=https://www.businesstoday.in/current/economy-politics/india-pips-russia-poland-to-secure--40-million-defence-deal-to-armenia/story/397235.html |website=businesstoday.in |date=March 2020 |access-date=2020-05-29}}</ref> In February 2023, it was reported that Armenia recently arrested an army Captain who was providing sensitive information about the radar to undisclosed foreign agencies for money.<ref>{{cite web | url=https://news.am/eng/news/742160.html | title=Armenia National Security Service exposes new case of high treason }}</ref><ref>{{cite web | url=https://theprint.in/world/armenia-arrests-army-captain-for-passing-on-info-to-foreign-agency-about-indias-radars/1348012/ | title=Armenia arrests Army captain for passing on info to foreign agency about India's radars | website=[[ThePrint]] | date=February 2023 }}</ref>
* In December 2021, six Swathi Mountain variants were ordered all of which were delivered by March 2023.<ref name=":0" /><ref name=":1" />
* On 30 March 2023, MoD signed a contract for WLR Swathi (Plains) with Bharat Electronic Limited (BEL) at a cost of over {{INRConvert|990|c|lk=on|year=2023}}. Induction was planned to be completed in 24 months.<ref>{{Cite web |title=Aatmanirbhar Bharat: MoD inks over Rs 9,100 crore contracts for improved Akash Weapon System & 12 Weapon Locating Radars Swathi (Plains) for Indian Army |url=https://www.pib.gov.in/www.pib.gov.in/Pressreleaseshare.aspx?PRID=1912309 |access-date=2023-03-31 |website=www.pib.gov.in}}</ref> Proposal for the contract was initiated in May 2022.<ref>{{Cite news |date=2022-05-12 |title=Indian Army to buy 12 more Made-in-India 'Swathi' weapon-locating radars for China border |url=https://economictimes.indiatimes.com/news/defence/indian-army-to-buy-12-more-made-in-india-swathi-weapon-locating-radars-for-china-border/articleshow/91517989.cms?from=mdr |access-date=2025-01-22 |work=The Economic Times |issn=0013-0389}}</ref> Last of the radar was delivered on 5 March 2025.<ref name=":2">{{Cite web |last= |first= |date=2025-03-04 |title=BEL delivers weapon locating radar to Indian Army ahead of schedule |url=https://psuwatch.com/defencewatch/bel-delivers-weapon-locating-radar-to-indian-army-ahead-of-schedule |access-date=2025-03-05 |website=PSU Watch |language=en}}</ref><ref>{{Cite web |last= |first= |date=2025-03-05 |title=BEL delivers 49th WLR-Plains SWATHI radar to Indian Army ahead of schedule |url=https://www.defencewatch.in/defence-news/latest-defence-news/bel-delivers-49th-wlr-plains-swathi-radar-to-indian-army-ahead-of-schedule |access-date=2025-03-05 |website=Defence Watch |language=en}}</ref>

== Operators ==<!--READ FIRST: This section is for cited entries only. Please do not add entries into this list without a citation from a reliable source. All entries without a citation will be removed. Thank you.-->
[[File:Swathi weapon location radar operators.png|thumb|300px|Map of Swathi WLR operators in blue]]

;{{IND}}
*[[Indian Army]] :
**Plains variant: 43 in service<ref>{{Cite web |date=30 March 2023 |title=Aatmanirbhar Bharat: MoD inks over Rs 9,100 crore contracts for improved Akash Weapon System & 12 Weapon Locating Radars Swathi (Plains) for Indian Army |url=https://pib.gov.in/PressReleasePage.aspx?PRID=1912309 |publisher=PIB India}}</ref><ref>{{Cite web |last=Negi |first=Manjeet |date=12 May 2022 |title=Indian Army to buy 12 more Made-in-India 'Swathi' weapon-locating radars for China border |url=https://www.indiatoday.in/defence/story/indian-army-made-in-india-swathi-weapon-locating-radars-china-1948718-2022-05-12 |access-date=2023-12-20 |website=India Today |language=en}}</ref><ref name=":2" />
**Mountains variant: 6 Mk2 in service.<ref name=":0">{{Cite web |last=Majumdar |first=Oishee |date=11 August 2023 |title=Indian Army inducts Swathi WLR mountain variant |url=https://www.janes.com/defence-news/news-detail/indian-army-inducts-swathi-wlr-mountain-variant |access-date=2023-12-20 |website=Janes.com |language=en}}</ref>
;{{ARM}}
*[[Armenian Ground Forces]] : 4 in service<ref>{{Cite web|url=https://www.businesstoday.in/current/economy-politics/india-pips-russia-poland-to-secure--40-million-defence-deal-to-armenia/story/397235.html|title=India pips Russia, Poland to secure $40 million defence deal to Armenia|website=businesstoday.in|date=March 2020 |access-date=2020-03-01}}</ref><ref>{{Cite web|url=https://aninews.in/news/national/general-news/india-beats-russia-poland-to-bag-40-million-defence-deal-in-europe20200301162402/|title=India beats Russia, Poland to bag $40 million defence deal in Europe|website=aninews.in|language=en|access-date=2020-03-01}}</ref>

== Specifications ==
<ref name="DRDO Brochure" /><ref name="DRDO Brochure 2" />

=== Performance === 
*'''Range:'''
**'''> 81&nbsp;mm mortars:'''     2–20&nbsp;km
**'''> 105&nbsp;mm guns:'''       2–30&nbsp;km
**'''Unguided rockets:'''   4–48&nbsp;km <ref name="The Indian Express">{{Cite web|url=https://indianexpress.com/article/cities/bangalore/bel-receives-order-army-procure-mountain-variant-of-weapon-locating-radar-7985127/|title=BEL receives order from Army to procure mountain variant of Weapon Locating Radar|publisher=The Indian Express|date=23 June 2022}}</ref>
*'''Elevation coverage:'''  −5 to 75°
*'''Azimuth coverage:'''    ±45° mean settable bearing
*'''Slewability:'''         ±135° within 30 seconds.
*'''Targets tracking:'''    7 simultaneously (maximum)
*'''Firing angles:'''       Both High & Low
*'''Aspect angles:'''       0–180°

=== Technical specifications ===
*'''Instrumented range:'''  50&nbsp;km
*'''Frequency band:'''      [[C band (IEEE)|C band]]
*'''Probability of:'''
**'''Detection:'''          0.9
**'''False alarm:'''        10<sup>−6</sup>
*'''Weapon locations:'''    99 stored (maximum)
*'''Digital map storage:''' 100 × 100&nbsp;km

=== Environmental specifications ===
*'''[[Operating temperature]]:''' –20 to +55&nbsp;°C
*'''Storage temperature:'''   –40 to +70&nbsp;°C
*'''Damp heat:'''             95% [[Relative humidity|RH]] at 40&nbsp;°C
*'''Operational altitude:'''  Up to {{convert|16000|ft|m}}

==See also==
*[[Counter-battery radar]]
*[[AN/TPQ-36 Firefinder radar]]
*[[AN/TPQ-37 Firefinder radar]]
*[[ARTHUR (military)]]
*[[Penicillin (counter-artillery system)]]
*[[Red Color]]
*[[SLC-2 Radar]]

==References==
{{reflist}}

==External links==
*{{usurped|1=[https://archive.today/20080131205848/http://www.drdo.org/Electronics/wlr.html Weapon Locating Radar]}} on DRDO website.
*[http://media.bharat-rakshak.com/aero/AeroIndia2007/Brochures/WLR.jpg.html WLR Poster from DRDO]
*{{usurped|1=[https://web.archive.org/web/20040120053425/http://www.acig.org/artman/publish/article_227.shtml Picture of the WLR]}} from [[Aero India]]-2003.
*{{cite news |author= Bharat Verma |title= How DRDO failed India's military |url= http://in.rediff.com/news/2008/jan/15guest.htm |publisher= Rediff News India |date= 15 January 2008 |access-date= 2008-01-23 |quote= DRDO scuttled a contract that was on the verge of being signed by India in 1997 for the import of a Weapon Locating Radar as the latter promised to produce it indigenously within two years.}}

{{Defence Research and Development Organisation (DRDO)}}

[[Category:Weapon locating radar]]
[[Category:Military radars of India]]
[[Category:Defence Research and Development Organisation]]
[[Category:Post–Cold War military equipment of India]]
[[Category:Military vehicles introduced in the 2000s]]