TAPAS/Rustom-II: India’s High-End Miltary Drone

DRDO. Udit Tripathi, UAV, ACAV, IAF, ISR

Aerial warfare has come a long way from bows and arrows to fighter jets to military drones. As per former U.S. Army General, Stanley McChryshtal, the military drones are an ‘all seeing eye’ permanently on call which can give reliable, real-time intelligence and apparently riskless, pinpoint accurate strike capability. The recent Azerbaijan-Armenia war and the ongoing Ukraine-Russia war have also highlighted the importance of military drones in modern-day warfare. India is not far behind in drone technology, where various concurrent projects on different types of drone development is going on. One such project which is set to begin its user trials soon is TAPAS BH-201 or Rustom-II.

(TAPAS BH-201, Image credit: Unknown)

Rustom-II/Tapas BH-201 (Tactical Advanced Platform for Aerial Surveillance Beyond Horizon-201) is a Medium Altitude Long Endurance (MALE) drone being developed by Aeronautical Development Establishment (ADE), Defence Research & Development Organisation (DRDO).

Evolution of TAPAS BH-201:

It all started with the development of manned, twin-seater Light Canard Research Aircraft (LCRA) by the National Aerospace Laboratories (NAL) team headed by Prof. Rustom Damania. The design of Rustom-I, a MALE drone developed by ADE, was derived from LCRA. In Rustom-I, necessary sensors and avionics were integrated and tested with the required aerodynamic configuration which later proved as a test bed for the development of Rustom-II. But it had its limitations of payload, endurance & altitude. To improve these limitations, Rustom-H was developed with a completely new and improved design. It featured a larger airframe, higher payloads, an increase in composite materials in the airframe, increased Lift to Drag ratio, higher redundancy (to enable safe operation in case of failure of the hydraulic systems), and stronger data link (for better communication with the ground stations) and better propulsion systems. Rustom-II or TAPAS BH-201 is the improved version of Rustom-H in user configuration to meet the specified Qualitative Requirements.

Timelines & Updates

  • The first maiden flight of Rustom-II was carried out on 16 November 2016 Aeronautical Test Range (ATR) in Chitradurga, Karnataka.
  • As per then DRDO Chief, S. Christopher, 9 prototypes would be built, advanced from the initial aircraft for testing purposes before the process of certification.
  • The first flight of Rustom-II/TAPAS BH-201 in user configuration with the higher capacity engine was carried out at Chitradurga, on 25 Feb 2018.
  • The sixth Rustom-2 prototype AF-6 crashed on 17 September 2019 due to link loss with the ground station and rough turbulence beyond the capacity of the control law.
  • The first take-off using GPS-SBAS (Satellite Based Augmentation System) based auto mode was successfully carried out on 7 November 2020. GPS Aided Geo-Augmented Navigation (GAGAN) was utilised for augmenting the accuracy of the GPS. 
  • The indigenous retractable landing gear was handed over by Combat Vehicle Research & Development Establishment (CVRDE) to ADE on 10 January 2021.
  • Automatic Take-off and Landing (ATOL) was carried out successfully using the GAGAN satellite communication (SATCOM) system on 13 November 2021.
    The official Twitter handle of DRDO shared the video  update of the same:
  • The first external pilot-assisted night landing on Tapas was successfully performed in the month of April 2022.
  • The project started at the cost of Rs 1,540.74 crores but was later revised to Rs 1,786 crores as of 2022.
  • TAPAS BH-201/Rustom-II is undergoing certification by the Centre for Military Airworthiness and Certification (CEMILAC) and the Directorate General of Aeronautical Quality Assurance (DGAQA). It will be the first ever indigenous R&D prototype UAV to get certified by CEMILAC and DGAQA.
  • Hindustan Aeronautics Limited (HAL) will produce the first five airframes for limited production between September 2022 and April 2023 in a staggered manner. It will be handed over for user trials before actual orders are placed for the aircraft by the user. Bharat Electronics Limited (BEL) will be the primary partner to produce onboard avionics and electronic systems. The flight control systems, avionics, and data-link systems for the first five aircraft have already been procured.
  • 76 TAPAS BH-201/Rustom-II drones are planned to be inducted as of now, 60 by the Indian Army, 12 by Indian Air Force, and 4 by the Indian Navy.

Key Features of Tapas BH-201:

  • Altitude & Endurance: It has a service ceiling of 30000 feet altitude and an endurance of 18 hours currently. As per former ADE Director, Dr. S. Venugopal, ADE has an ‘alternate plan’ to meet the requirements of 24-hour endurance.
  • Range: It has a range of 250+ km Line of Sight (LoS) from the data link (uses C Band frequency) developed by Defence Electronics Application Laboratory (DEAL) by DRDO. Also, it has a 1000+ km range from SATCOM (uses Kᵤ Band frequency) using the GAGAN system.

Sensors: Various sensors are used in the aircraft to communicate it with ground stations, other aircraft and satellites. Some key sensors are:

(TAPAS BH-201 sensors, Image credit: Amit Raj Kashyap @Amitraaz, Twitter)

i. Airborne Integrated Payload Processing Unit (AIPPU) & Ground Integrated Payload Processing Unit (GIPPU): It uses 3 wide bands and 4 narrow band channels. The role of these sensors is to compress, encrypt the video input and send it to ground stations or satellite as it is both LoS & SATCOM compatible.
Airborne Spread Spectrum Modem (ASSM): It processes the spectrum of radiation the aircraft operates; does data level encryption and counter the jammers.
ii. Radio Finger Printing System (RFPS): It stabilizes a wide band of frequencies through a particular channel and also helps in the cancellation of noises.
iii. Solid State Power Amplifier (SSPA): It supports wide band operation, perform the thermal management of the system, manages heat dissipation, generates 20W output power and helps in open circuit protection.
iv. Traffic Collision Avoidance System (TCAS): It is an aircraft collision avoidance system designed to reduce the incidence of a mid-air collision between aircraft.
v. Radar Warning Receiver (RWR):  It detects the radio emissions of radar systems and issues a warning when a radar signal might be a threat. This warning can then be used, manually or automatically, to evade the detected threat.
vi. Identification, friend or foe (IFF): It is a system used to differentiate between friendly aircraft (within the same armed force) and adversary aircraft. Currently, IFF Mk XII is used as a common sensor for most operating aircraft of the Indian armed forces. 
vii. COMINT: It is a high-performance airborne solution allowing to search, detection, listen and localize all types of civil and military communication signals (fixed frequency, frequency hoppers, burst).
viii. ELINT:  ELINT usually means the evaluation of ‘non-communication’ signals (signals from radars, missiles and guidance systems, aircraft etc.). The intercepted signals are then further analyzed to information like the angle of arrival, frequency of electromagnetic radiation by the emitter, pulse width, pulse repetition period, beam width of the emitter’s antenna, etc. This information is then used to identify the type of emitter, its travel path and its location.

  • Radar: It features Synthetic Aperture Radar (SAR) made by Electronics and Radar Development Establishment (LRDE), DRDO. It is a mechanically steerable radar, capable of performing functions such as map generation, 3D mapping, patrol missions etc. It works in 3 modes:
    i. Strip mode: Scans a large area in the form of a strip (Resolution: 3-6m).
    ii. Spotlight mode: Scans a particular immovable target (Resolution: 0.6-1m).
    iii. Ground Moving Target Indication (GMTI) mode: Scans a moving target on the ground (Resolution: 25m).
  • Propulsion: Currently the aircraft features Austro E4 engines with a power of 168 HP. The engines will be replaced by indigenous higher-powered 220 HP diesel engines from CVRDE. ADE floated a tender for the same earlier in 2022. Currently, the aircraft features Austro E4 engines of with a power of 168 HP. The current engines are said to be replaced by higher capacity engines from Combat Vehicles Research & Development Establishment (CVRDE), DRDO in near future.
  • Payload: It has a total payload capacity up to 350kgs. The payload consists of various devices and sensors such as Medium Range/ Long Range Electro Optic (MREO/LREO), Electronic Intelligence (ELINT), Communication Intelligence (COMINT), Synthetic Aperture Radar (SAR), Maritime Patrol Airborne Radar (MPAR); Situational Awareness Payloads such as Identify Friend or Foe (IFF), Traffic Collision Avoidance System (TCAS), UAV Communication Repeater/Relay (UCR).
  • Stealth aspect: Kevlar as Radar Absorbent Material (RAM) along with Carbon Fibre Composites (CFC) are sandwiched into a layer of 3mm thickness. This layer on the airframe is responsible for minimal radar deflections, thus improving the stealth characteristics of the aircraft.
  • Combat capability: As per Y Dilip, Director ADE, though the primary role of Tapas is ISR (Intelligence, Surveillance and Reconnaissance), it is pre-designed to carry certain weapons and can be converted into an armed platform as and when required by the user.
  • Indigenous Content: The aircraft currently has 75% indigenous content with most of the critical subsystems developed indigenously. The indigenous content will rise further when the indigenous engine from CVRDE is integrated in near future.

Importance of TAPAS/Rustom-II

India is a multi-billion dollar market for military drones which currently have very useful applications such as monitoring of LoC & LAC, striking terrorist hubs, monitoring of sea lanes, longer duration missions etc. Tapas will be a significant step in the military drone market for India as with its development many important, critical technologies, components and subsystems have been developed indigenously and mastered. Tapas can prove to be a great template for the upcoming drones similar to the Tejas project where experience gained in the consolidation of the mastered technologies has contributed to the development of bigger and more capable platforms like Tejas Mk2, TEDBF etc. It will also provide a window of opportunity for private industry involved in the manufacturing of various Line Replacing Units (LRUs) for HAL under a modular approach.

Tapas/Rustom-II project is a significant development in the Indian drone industry and even has the potential of becoming an ‘industry coming off age’ for the development of military drones in India similar to the Tejas project. It’s high time the user, i.e. Indian armed forces order it in good numbers than rely on foreign silver bullets for a similar role. This will move India a step closer to self-reliance or ‘Atmanirbhar Bharat’ and will also place India in the list of a few nations that manufacture high-end military drones.

About the Author: Udit Tripathi, @i_udit_t, Twitter. The views expressed are the author’s own.

Header Picture Source: DRDO


#HamaraHeroes-3 | DRDO’s go-to man Dr S Venugopal shares insights into Tapas, LRLACM, SWiFT & more, https://www.youtube.com/watch?v=Dgd1UceGh24

Published by Anil Chopra

I am the founder of Air Power Asia and a retired Air Marshal from the Indian Air Force.

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