India's Air Defense System: Radar Airspace Monitoring Systems
Over the course of a month, Military Review published several articles dedicated to the Indian air defense system and combat aviationAfter reading them, I felt the urge to write a review on this topic, as these articles give a distorted or incomplete picture of the system. Defense India
This review series, beginning with a section on airspace radar surveillance, will not discuss Indian "elephants," "dances," or "cuts." I'll leave that to the regular contributors, who are far more knowledgeable on these matters than I am.
This publication, based on publicly available information, will briefly describe story The development of radio-technical troops examined the radar systems available in the Indian Air Force and Air Defense Forces, the locations of permanent radar posts and command posts, and the command structure.
Indian airspace radar systems in the 1950s–1970s
After India's independence in the 1950s, approximately two dozen Type 11, Type 13, AN/TPS-1E and AN/MPS-16 radars were purchased from the UK and the US.
American-made AN/TPS-1E radar
In the early 1960s, the border areas with Pakistan and China were controlled by six fixed radar posts equipped with outdated American and British radars that were unable to reliably track low-altitude air targets or support the operations of their own aircraft, which played a negative role during the Sino-Indian War of 1962.
Radar antennas AN/FPS-89 and AN/FRS-100
In the early 1960s, the United States acquired six AN/FRS-100 standby radars, which were modern at the time and operated in tandem with AN/FPS-89 altimeters, and the USSR acquired twelve P-30 radars with PRV-10 altimeters.
Following the Indo-Pakistani War of 1965 and the cessation of military-technical cooperation with the United States, the Indian Air Force faced a critical gap in radar control of border airspace, finding itself with aging radars and unreliable warning networks. Under these circumstances, an emergency procurement of radar equipment, communications, combat control systems, and anti-aircraft systems began. missile systems and fighter jets. Contracts were signed with the USSR for the supply of P-12 and P-35 radars, MiG-21 fighters, and SA-75MK Dvina anti-aircraft missile systems.
Radar P-30
In the late 1960s, a plan was adopted to create a continuous radar field over the entire country, and the Indian military initially considered acquiring Soviet P-14 meter-wave radars, which provided extensive coverage at medium and high altitudes. However, the government in New Delhi, having had negative experiences with sophisticated American military equipment left without spare parts and service after Washington imposed an embargo, decided not to "put all its eggs in one basket" and to diversify its procurement.
Indian airspace radar surveillance systems currently in use
In the early 1970s, negotiations with France for the acquisition of powerful Thomson-CSF THD-1955 fixed-wing three-dimensional radars were successfully concluded. Initially, India purchased one complete radar system, as well as components for two systems, which were assembled domestically by Bharat Electronics Limited.
Stationary radar THD-1955
These decimeter-wave radars had excellent jamming resistance for their time. They provided long-range detection, covering India's northern borders with a range of over 420 km and a ceiling of 30 km. A total of 12 THD-1955 radars, manufactured in India by BEL Ghaziabad, were deployed. The first of these radars, assembled under French license, was commissioned in 1976, marking a significant milestone in the development of India's air defense system. Some of the modernized and overhauled THD-1955 radars remain operational. In 2024, a program to modernize the remaining THD-1955 stations was completed, converting them to digital mode, which should extend their service life by 15 years.
Simultaneously with the deployment of fixed radars, the coordinates of which were known to a potential adversary, Thomson-CSF and Bharat Electronics Limited began jointly developing the PSM-33 three-dimensional radar, which could be relocated if necessary.
PSM-33 radar antenna post
Indian sources report that the first PSM-33 radar was commissioned in 1983. The deployment of these stations, with an instrumented range of up to 260 km, allowed the gradual phase-out of the outdated Soviet P-30 two-dimensional radars, which had been in intensive use for over 20 years.
Due to its modular design and the relatively light weight of its individual components, PSM-33 radar antenna posts were sometimes placed on the roofs of buildings, which increased tactical flexibility and the likelihood of detecting low-altitude targets.
In 1986, a modernized version, the PSM-33 Mk.2, also known as the TRS 2215, was introduced.
TRS 2215 radar antenna post
The station, operating in the 2,9–3,1 GHz frequency range, has a pulse power of 700 kW. Its instrumented range reaches 480 km.
In the mid-1980s, the production of mobile two-coordinate radars Indra I (GRL 600) began, mainly intended for timely target designation of anti-aircraft artillery and short-range missile systems.
The station, operating in the 1 to 1,5 GHz range, is mounted on two all-terrain trucks. Power is supplied by a standalone diesel generator or from a centralized grid. With a pulse power of 45 kW, the detection range of low-altitude targets reached 60 km. An improved version is the Indra II (GRL 610), with a pulse power of 100 kW and a range of 90 km.
Although the Indra family of mobile radars were inferior in performance to similar radars purchased from the USSR, their development and production allowed the Indian electronics industry to rise in level.
In the 1970s and 1980s, more than a hundred mobile P-15, P-18, P-19, and P-40 radars were delivered alongside the S-125M Pechora-M and Kvadrat air defense missile systems, followed by ST-68 standby radars in the late 1980s. Currently, all hopelessly outdated and extremely worn-out P-12, P-15, P-35, and P-40 radars have been decommissioned. However, it appears that P-18 meter-wave radars are still in use in India.
The P-18 radar is a further development of the widely used P-12 radar, featuring updated components, improved performance, and a more comfortable operating environment for operators. The main components of the radar are mounted on two Ural-375 vehicles. One contains a van with electronic equipment and operator workstations, while the other contains an antenna mast. Detection range is highly dependent on the altitude of the aerial target. For example, at an altitude of 20 km, a fighter-type target in the absence of jamming can be detected at a distance of 260 km, and at an altitude of 0,5 km, the range can be 60 km.
The P-19 low-altitude, decimeter-wave radar, also still in service with the Indian Armed Forces, is capable of detecting aerial targets at ranges of up to 160 km. Its ceiling is 6000 m.
The station's components are based on two ZIL-131 vehicles. One chassis houses the antenna post, while the other contains the control room containing the radar equipment, interface equipment for other radars, a radar interrogator, data acquisition and transmission units, and a suite of measuring and communications equipment.
Since the P-18 and P-19 stations are two-coordinate, for full measurement of the spatial coordinates of an air target they were interfaced with the PRV-13 and PRV-16 altimeters.
PRV-16
The PRV-16B altimeter, mounted on a KrAZ-255B chassis, operates in the centimeter waveband and is protected from active and passive interference, meteorological phenomena, and extended local objects. Its maximum range is 300 km.
The first mobile three-dimensional radar in Indian radio-technical units was the ST-68U (19Zh6), produced since 1980 at the Iskra radio plant in Zaporizhzhia. In total, India received approximately three dozen ST-68U radars; currently, fewer than ten of these radars remain operational. All of them are deployed in the northern and central parts of the country. Due to their high level of wear, they are not on permanent duty and are intended to provide target designation for the S-125M air defense missile systems deployed near airbases.
At the time of its development, the ST-68U was one of the best radars of its class, surpassing most foreign counterparts. This station features an antenna post with a rotary device and a control cabin mounted on a single semitrailer.
The ST-68U radar, operating in the 2850–3200 MHz frequency range, offers excellent mobility and high jamming immunity. Furthermore, it does not require a radio altimeter for precise coordinate determination. This system is capable of effectively engaging low-altitude targets, including complex ones such as cruise missiles, in active and passive jamming environments, with intense ground reflections, and in adverse weather conditions, and simultaneously tracking up to 30 targets. It can detect targets with an RCS of 0,1 m² flying at an altitude of 100 m at a range of 46 km, and at medium and high altitudes at a range of 160 km.
In the mid-1990s, a contract was signed with the Polish company PIT-RADWAR to create a radar that could be transported by rail or in the cargo compartment of an Il-76 military transport aircraft without dismantling some of its components.
The first Polish-made radar, designated CAR-1100, operating in the 2–4 GHz frequency range, was delivered to the customer in 2001. Its air target detection range reached 240 km, with a ceiling of 30 km. The main components of the radar were mounted on two Tatra 815 trucks. Following trial operation of several radars of this type, the Rohini mobile phased array radar was developed in India.
Rohini radar antenna post
All the main components of the Rohini radar are housed on three truck chassis. The three-axle truck houses the antenna post and radar equipment. A sealed van houses the communications, display, and data processing systems, as well as workstations for three operators. Another truck carries a diesel-electric generator, providing independent power.
The instrumented range is 200 km, with a ceiling of up to 18 km. It can track 150 targets. Deployment is accomplished in less than 20 minutes. These radars are attached to Akash air defense missile systems and are used independently as part of mobile radar posts. As of 2024, the military had approximately 40 Rohini-type mobile radars.
Ten years ago, India signed a contract with the international industrial group Thales, headquartered near Paris, for the supply of 19 GS-100 LLTR mobile radar systems. Of these, 13 were assembled at the Bharat Electronics facility in Ghaziabad.
GS-100 LLTR radar antenna post
The S-band radar is capable of detecting fighter-class targets at a range of 180 km. The Indian Air Force and Air Defense Forces' requirement for such radars is estimated at 70 units. A domestic version, based on the GS-100 LLTR radar and designated Ashwini, is currently being produced.
A number of sources claim that India has purchased several Israeli ELM-2084 AESA radars to control the fire of its anti-aircraft missile systems.
ELM-2084 radar
The radar, produced by ELTA, a subsidiary of Israel Aerospace Industries, is capable of detecting both air and ballistic targets and providing fire control for the interception of short-range ballistic missiles.
The Arudhra phased electronically scanned array radar is another new addition to the Indian Air Defense Forces' inventory. It was first unveiled at the Aero India 2011 aerospace exhibition in Bangalore. Later, the truck-mounted antenna post of this radar was displayed during military parades. Currently, 16 radars of this type are in active service.
The Indian military makes no secret of the fact that the Arudhra S-band radar, designed for the early detection of cruise and ballistic missiles, is based on the Israeli ELM-2084. It claims to have a detection range of 300 km for targets with an RCS of 2 m², while targets with an RCS of 0,2 m² can be detected at a distance of 160 km. The instrumented range is up to 400 km.
The Indian company Alpha Design Technologies, in collaboration with the Belarusian Design Bureau Radar, developed the Surya three-dimensional meter-wave radar based on the Vostok-3D radar. It is capable of effectively detecting stealthy aircraft. The Surya radar consists of three main components: an antenna and equipment vehicle, a remote automated workstation, and an autonomous diesel power plant.
Surya radar antenna post
During international aerospace exhibitions, it was announced that an aerial target with an RCS of 1 m², flying at an altitude of 5 to 10 km, can be detected at a range of 280 km. The maximum instrumented range for large targets at medium altitudes reaches 500 km. The ceiling is 18 km. It can automatically track at least 250 aerial targets. If the enemy is jamming, the equipment can automatically track the source's bearing. A total of six such stations have been ordered, and the first will be delivered to the troops in early 2025.
About 20 years ago, two Israeli-made ELM-2080 Green Pine active phased array (AESA) radar stations were commissioned near the city of Kolar in the Indian state of Karnataka, in the southern part of the country and on the coast of the Bay of Bengal, not far from the missile range located on Abdul Kalam Island.
ELM-2080 Green Pine radar antenna post
The station, manufactured by Elta Systems, is typically deployed in a well-prepared position and operates at frequencies of 500–2000 MHz. It is designed to detect ballistic targets and provide target designation information to anti-missile systems. The target detection range under favorable conditions can reach 900 km.
Google Earth satellite image: EL/M-2080 radar north of Kolar
At the first stage, the antenna arrays were placed in the open, but about 10 years ago they were protected from the effects of adverse meteorological factors by radio-transparent domes.
Google Earth satellite image of the EL/M-2080 radar deployed on the coast of the Bay of Bengal near the Abdul Kalam missile range.
After a detailed study and accumulation of operating experience of the Israeli EL/M-2080 anti-missile radars, in 2009 the Indian electronics company Bharat Electronics Limited, with the participation of Astra Microwave and Cape Electronics, created the Swordfish (LRTR-I) station, designed to support the functioning of the national missile defense program.
In 2011, the improved Super Swordfish AESA L-band missile defense radar (LRTR-II) became operational, capable of tracking objects in low Earth orbit with an area of 0,25 m² at a distance of 1000 km and 0,09 m² at a distance of 800 km.
Military observers write that the new Indian stations are designed to provide defense against medium-range ballistic missiles in the capital area. According to publicly available satellite imagery, the LRTR-I and LRTR-II radars are located on a mountain ridge 12 kilometers west of Udaipur in Rajasthan. However, Indian officials have not commented on this.
Google Earth satellite image of a Swordfish and Super Swordfish radar in the highlands of Rajasthan.
Satellite images show that the radio-transparent domes have different diameters, which indicates that the active antenna arrays of the Swordfish and Super Swordfish radars have different geometric dimensions.
To detect low-altitude airborne targets, the Indian Air Force uses six aerostat-based radar systems with Israeli-made EL/M-2083 Airstar radars.
The radar, capable of monitoring airspace over an area of up to 2600 km², is lifted to an altitude of 4,5 km by an American-made TCOM 71M tethered aerostat with a lifting capacity of 1,6 tons. Data is transmitted from the aerostat to the ground via fiber optic cable.
Google Earth satellite image of a balloon-borne radar post near Barnala in Punjab.
Five known sites for Indian aerostat systems are located along the border with Pakistan. Apparently, another Airstar system is in reserve.
Mobile Reporter radars, operating in the 8-10 GHz frequency range, are intended for use in military air defense.
All components of this type of station are mounted on a truck chassis. The mobile Reporter radar, with a range of up to 40 km, is capable of detecting airborne targets at altitudes of 15 to 4000 meters and providing target designation for anti-aircraft artillery and short-range air defense systems.
Along with the S-400 air defense missile system, India received several 91N6E and 48Ya6 K1 "Podlet" radars.
RLK 91N6E
The 91N6E phased array radar system, designed to detect air targets across the entire altitude range, operates at frequencies of 2,9–3,3 GHz and has an instrumental range of over 550 km.
The 48Ya6 K1 "Podlet" radar system with a phased array antenna operating in the S-band is used to detect air attack weapons at low and extremely low altitudes.
RLK 48Ya6 K1 "Podlet"
However, this system can also be used to track conventional targets. In a simple jamming environment, at an altitude of 8-10 km, the range is 300 km. The number of targets simultaneously tracked is up to 200. The system's deployment and dismantling time is 20 minutes.
As of today, more than 40 radar posts have been deployed in India, of which approximately two-thirds are operational permanently, providing a continuous radar field at medium and high altitudes over the northern and central parts of the country.
Map of the location of radar posts in India as of 2020
The diagram shows that most of the radars are deployed in the northern regions, monitoring directions from Pakistan and China, as well as on the west coast.
Communications and command structure of the Indian Air Force and Air Defence
The 1962 India-China conflict revealed the unreliability and poor resistance to interference of combat command and control systems, which relied primarily on civilian-standard landline telephone and telegraph lines and relatively low-power VHF radios. Following the defeat in the conflict with China, appropriate conclusions were drawn.
The central and regional command posts were connected to fixed radars via underground cables, backed up by radio relay channels. Radiotechnical units capable of changing their locations were equipped with medium-power Soviet and Western-made radio sets mounted on vehicle chassis, as well as tropospheric communication stations.
Significant investment of material and intellectual resources, as well as the use of advanced foreign expertise, enabled the gradual creation of a highly sophisticated and robust combat control system for fighter aircraft and the ground-based air defense component, as well as the implementation of a jam-resistant Mk-X standard identification friend or foe system. In the 1990s, the transition to multi-channel digital communications and automated control systems began.
To improve its air traffic management capabilities and ensure airspace control in both peacetime and wartime, the Indian Air Force has initiated a $1,3 billion, multi-phase programme to create a modern, joint civil-military network-centric system that uses common procedures, decision-making and data-sharing protocols.
Air traffic control and flight management services at Indian Air Force bases have also been modernized. The expected result of these technical and organizational measures is a significantly expanded aircraft identification zone and real-time air situation display. The air traffic control and management system, based on modern radars integrated with communications and control equipment, should ensure airspace monitoring for several hundred kilometers from India's territorial borders and the timely deployment of interception capabilities. Ballistic missiles should be detected at a range that allows for the timely deployment of missile defense systems to reliably protect strategically important facilities.
By 2012, the Integrated Air Command, Control, and Communications System (IACCS) was complete, after which its individual components were further improved and updated. Along with radio relay and tropospheric communications, fiber-optic lines began to be widely used, enabling real-time transmission of radar images from fixed radars, high-speed information exchange between multi-level structures, and rapid target designation for air defense missile systems and fighter-interceptors.
Over the past decade, the Indian Armed Forces have placed significant emphasis on the development of mobile satellite communications, which provide high levels of interference immunity, secrecy, and multi-channel capabilities.
The Indian Air Force currently deploys a layered airspace control system, comprising five air defense regions, each comprising ten sectors. Command and control of these subordinate forces and assets is exercised from the Air Force Air Defense Operations Center in New Delhi.
The first echelon is formed by the Ajes radar network, designed for long-range detection and tracking of high-altitude air targets and fighter aircraft guidance. Deployed along the country's western and northeastern borders, it consists of border mobile visual observation and warning posts, followed by a line of individual radar posts. This network connects to the operational centers of the Western and Southwestern Air Defense Regions, the command center of the Southern Air Defense Region, and ten command and warning centers of the air defense sectors.
The second echelon is formed by the Badz area-location network. It is tasked with ensuring control and protection of airspace in the areas surrounding airbases and important government and military installations. It is divided into air defense sectors, each with a single command and control center, separate radar stations, and weapons.
India is divided into five commands, each with its own area of responsibility. The Central Air Command is headquartered in Prayagraj, Uttar Pradesh; the Eastern Command is headquartered in Shillong, Meglaya; the Southern Command is headquartered in Thiruvananthapuram, Kerala, in the southeast; the Southwestern Command is headquartered in Gandhinagar, Gujarat; and the Western Command is headquartered in the capital, New Delhi.
According to information published in open sources, the Main Air Defense and Air Traffic Control Center is located at Basant Nagar Air Base (415th Base). The Indian Air Force's central communications hub is located in New Delhi. It directly oversees six major communications hubs located across the country.
Regional air defence command posts, air traffic control centres and main communication hubs are located at military airfields and bases: Adampur, Agra, Ambala, Bagdogra, Bareilly, Bhatinda, Bhuj, Bidar, Chabua, Chandigarh, Gorakhpur, Gwalior, Halwar, Hashimara, Hindon, Jaisalmer, Jamnagar, Jodhpur, Jorhat, Kalaikunda, Nal, Naliya, Pathankot, Pune, Sirsa, Suratgarh, Tezpur, Uttarlai, Yelahanka and Zopuitlang.
Map of the locations of the main and regional air defense and air force command posts in India
The presented layout of the Air Force and Air Defense command posts leaves no doubt as to which areas the Indian military and political leadership considers the most important for defense. It's worth noting that adjacent to these same command posts, protected from air strikes by anti-aircraft systems, are permanently operational radar posts.
The Indian Air Force's airborne early warning aircraft can also be considered airspace surveillance radar assets. However, due to space limitations, these will be discussed in a future publication.
To be continued ...
Information