DRDO August 2007 Newsletter-Techfocus Special on Dhanush

DRDO August 2007 Newsletter-Techfocus Special on Dhanush


Missiles are a must for any modern military outfit. They act as a force multiplier as is evident from the recently fought wars in the South Asia and the Gulf. Most of the missiles technologies come under the purview of sanctions imposed by the developed countries.

To provide thrust and to promote self-reliance in the areas of missile systems, an Integrated Guided Missile Development Programme was launched by the DRDO in 1983 to develop a family of strategic and tactical guided missiles.

Since then DRDO has achieved a unique degree of success leading to the development of a number of missile systems like Prithvi (a short-range ballistic missile), Agni (medium-range missile), Akash and Trishul (short-range surface-to-air missiles), and Nag (third-generation antitank guided missile). Prithvi has now been inducted into the Services, while the serial production of Agni has started.


IGMDP programme sanctioned in 1983 provided for a major thrust in the design and development of indigenous technologies and capabilities in the field of missiles. It was both a learning curve and a challenge.

The technologies, expertise and capabilities built have provided a platform enabling the country to take a quantum leap into development of futuristic world-class missiles. Agni and its variants have been successfully inducted and handed over to the Army. Today Prithvi and its variants find a place of pride in the inventory of Indian Army, Indian Air Force, and Indian Navy.

Project Dhanush, a Naval variant of Prithvi missile on ship, and its deployment from a moving platform, was a major technological challenge both in terms of hardware and software. It enabled demonstration of the indigenous capability for the stabilisation of the missile launcher and first vertical launch of Prithvi variant missile from an OPV class of ship.

Successful enhancement of range, development of GPS INS-based close-loop guidance system and conduct of ‘Acceptance Test Firing’ independently by the naval teams have boosted the users confidence in the indigenous systems/technologies.

Successful trials of the BrahMos missile, both naval and land version, and their induction into Indian Navy and Indian Army has been another landmark in the development and demonstration of the indigenous capability.

The successes achieved in these fields are attributable to the synergy developed between the DRDO, Services, and academic institutions; PSUs like Bharat Dynamics Limited, Hindustan Aeronautics Limited; and private industry. {PPP-Public-Private Partnership}

Today the country has a demonstrated capability for design, development and manufacture of all types of missiles.

I am glad to note that DESIDOC is bringing out a Special Issue of Technology Focus to highlight the success achieved by Project Dhanush. This should motivate one and all to come together, overcome the technological challenges and reduce the dependence on imported systems/technologies.
Dr VK Saraswat
Distinguished Scientist &
Chief Controller R&D (MSS)

After successfully developing these missiles, DRDO has also developed indigenously Dhanush missile (a naval variant of Prithvi) and a supersonic
cruise missile, BrahMos, in collaboration with Russian entity Mashinostroyeniye.Both the missiles are ready for induction into the Services after successful trials at sea. This issue of Technology Focus is highlighting the salient features and achievements of Project Dhanush.

Project Dhanush was sanctioned by the Indian Navy to integrate and demonstrate the feasibility of launching variant of Prithvi from a ship.

The translation from the technology demonstrator to weaponisation configuration , and induction of the Dhanush weapon system has been completed with the successful 'Acceptance Test Firing' conducted by the user, and after achieving all the planned mission objectives.

The salient features and achievements of Project Dhanush required development and realiasation of a number of systems. Some of these are given below:

Realisation of Ship-based Systems

Following ship-based systems have been developed:

Launcher Stabilisation System (LSS) including electronics and hydraulics for stabilisation of a five-ton weight class Prithvi missile within 90±1” , in disturbance of ±10” of roll, and ±5” in pitch (sea state 4) on board ship, and deployment of a vertically stabilised Prithvi variant from ship.

Ship Motion Simulator with capability to generate roll of ±30 and pitch of ±15 for testing/evaluation of the LSS on shore. This was subsequently upgraded and converted into a LSS for the second ship.

Transporter Erector Trolley (TET) for transfer of Prithvi variant from the safe storage (SS) container and its integration on the LSS.

Object Transfer Trolley for handling of SS container (14 ton with the missile) on board the ship.

SS Container for safe storage of the Dhanush during transportation to and fro from the depot and for stowing on board ship.

Integrated Electronics System consisting of
*Power supply and distribution units to ensure availability of clean and regulated power supply at all the times for all the elements of the Dhanush weapon system.
*State-of-the-art Dhanush fire control system based on real-time operating virtual machine environment (VME)-based open architecture system for the auto launch of Dhanush with provision for future upgradation.
*Object handling system for semi-automatic, safe and fast integration of the Dhanush with the LSS.
*LSS controller for stabilisation of the LSS to the required accuracy in sea state 4 conditions. This has enabled deployment of the Dhanush missile in sea state up to 3.

Modification of the Ships
Naval ships have been modified for integration of the Dhanush weapon system and safe operation of the ship-based systems (weight approximately 40 ton).

Following design, development and modification in the software were carried out for:-

Transfer alignment based on Kalman filter technique for alignment of inertial measurement unit (IMU) with the master inertial navigation system (INS) SIGMA 40 to define the azimuth for the missile trajectory and control and guidance.

Global positioning system (GPS)-INS fused navigation to reduce the cross-range error/cross-range error probability (CEP) at the impact point. The technology has completely eliminated the proportional dependence of CEP to range.

Launch point prediction software for prediction of the launch point on a moving platform.

Existing Cacoon software has been modified to enable deployment of missiles from any latitude and longitude.

Command control software to prevent unauthorised launch.

Integration of thrust vector control (TVC) backup in the analog-to-digital conversion (ADC) phase to augment the control effectiveness for extended range missiles based on 'dynamic sharing logic'.

Mission software.

Modification of the Airframe Sections

Modification of the airframe sections has been done to increase the range of Dhanush beyond 250 km by increasing the tank length and effective surface area of the control surfaces, and by augmenting and strengthening the control scheme/algorithm using the latest control techniques.

Secure C3 Network
A command, control, communication network has been implemented for reliable, assured and safe communication among all authorities.

Ground Systems
Fourteen types of ground systems have been realised for utilisation during preparation of Dhanush missile at depot. These include three special ground systems—MOSAIC D, missile carrier vehicle, and 40 T crane—especially developed for Dhanush missile system.

Composite Helo Deck
With the integration of the Dhanush weapon system, the flexibility of the Dhanush-capable ship to operate the helicopters was compromised. To restore this capability, DRDO took on the task of realising and integrating a helo deck made from lightweight composite materials.

DRDO has now developed a helo deck made of vinyl ester and E glass fabric on board such ships. With this, the Naval Commanders have the flexibility to operate the Dhanush class off-shore patrol vessles (OPV) in either Dhanush or helo role.

The successful translation of the technology demonstrator project to the final goal of weaponisation demonstrates the unique synergy created between the Indian Navy, DRDO, PSUs (BDL, HAL, etc.), and private industries (M/s L&T Mumbai, SEC Industries Private Ltd., VEM Technologies, etc.) to realise the mission objective for design, development and induction of indigenous technologies for the Defence forces.

Dhanush weapon system has continuously evolved with technology upgrades during the translation from technology demon-strator to the inducted weapon system held in the inventory of the users.

The range of the Dhanush has been increased beyond 250 km, the Flight Control System has been changed/upgraded from 80286 MB II technology to open architecture VME-based real-time operating system, and user's feedback and inputs have been incorporated to simplify the ship-based operations in the area of man-machine interface and graphic user interface.

The following technologies have been realised/developed in-house during the execution of this project:
a. Realisation of extended-range class of ship-launched Dhanush missile.
b. Stabilisation system for stabilisation of missiles/radar/ guns/rockets weighing up to 5 ton.
c. Vx works-based VME operating system for Fire Control Systems of missiles/guns/rockets.
d. Linear motion rail technology for safe and reliable operations and handling of very heavy systems/objects in the presence of constant and unpredictable disturbances (roll and pitch motions).
e. Secure command control communication network.

Portable Carbogen Breathing Apparatus For Protection Against Noise-Induced Hearing Loss

Exposure to noise is well known to cause damage to the auditory system.Today, noise-induced hearing loss (NIHL) is a major and increasing problem in the industrialised countries, stemming both from the workplace and from leisure activities. The degree of hearing impairment depends on the intensity of the noise and the duration of exposure.

Experiments to study the mechanism of action of noise have established that exposure to noise initially causes temporary loss of hearing sensitivity, commonly known as temporary threshold shift (TTS).

If this loss is not recovered during rest pauses, it slowly turns into permanent hearing impairment referred to as noise-induced permanent threshold shift (NIPTS). Intense acoustic stimulation has been reported to produce discernible change in blood supply and oxygen tension of hair cells.

Thus, TTS produced by exposure to noise may be due to increased oxygen
consumption by hair cells coupled with depletion of blood supply caused due to vasoconstriction.

Therefore, any system that could counteract these effects is considered suitable to mitigate the degree of hearing loss. Carbogen, a gas mixture of 95 per cent Oxygen and 5 per cent Carbon dioxide, is a well-known powerful vasodilator of the cerebral capillary beds.

Its potential has been utilised by DRDO to counteract the vasoconstrictive effect of noise. During the laboratory studies, it was observed that administration of Carbogen even for short duration of 5 min before and after exposure to occupational noise provided dual benefit by reducing the magnitude of TTS development and accelerating the recovery process for normalisation of hearing status.

The equipment used earlier to administer Carbogen was bulky and cumbersome to handle and use. DRDO has designed a mobile Carbogen Breathing Assembly to deliver Carbogen for a period of 5 min before and after exposure to occupational noise in order to minimise and mitigate the adverse effects of noise on the auditory system of a human being.

The assembly is trolley-mounted for easy manoeuverability and comprises a gas cylinder, regulator, and humidifier and breathing masks in an aesthetically appealing module.

This mobile apparatus provides facilities for normal breathing in sitting and standing positions. The system finds application as a protective device for the conservation of hearing in workers occupationally exposed to intense noise for prolonged period such as the engine room of ships, naval dockyards, Indian Air Force, Ordinance Factories, traffic police personnel, and industries, etc.

The integrated system is portable, compact, and simple to use. The functional aspects of the prototype has been successfully evaluated in the laboratory set up as well as at Defence establishments (Indian Navy, Air Force and Army Workshops) where the personnel have to operate in an intense noise environment.

The system has been hailed as being effective, safe and user-friendly and one that supports the application of Carbogen as an effective prophylactic against NIHL.

The basic design of the system incorporates the carbogen cylinder coupled with flow control valve and timer. A nebuliser, housed in the body of the equipment, humidifies the gas before inspiration.

The system design has catered for reduced floor space requirement, weight and cost considerations. Design for fabrication of commercial prototypes of Carbogen Delivery System has been awarded to two vendors (M/s Vijay Sabre Safety Ltd, Mumbai, and M/s S.B. Equipment, New Delhi, and are likely to be available in the market soon.

A multi-user Kiosk workstation has also been developed to facilitate the administration of Carbogen to 10 individuals at a time.

Following the successful trials conducted by the Indian Navy on the efficacy of breathing Carbogen in ameliorating NIHL, the Indian Navy has communicated its desire to acquire 12 Carbogen breathing assemblies towards the first phase of induction in the Navy. DGAFMS has approved the installment of the system in nine medical units under different Commands.

Salient Features
*A strudy, user-friendly and ergonomically designed system.
*Easy-to-operate system that does not require the use of a skilled operator.
*Switch to start/stop the flow of Carbogen gas with light indicators for indicating the start and flow of the gas along with a timer for indicating the termination of 5 min of Carbogen inhalation.
*Adjustment for control of pressure and flow of Carbogen gas @ 10 liters per minute.
*Dual-stage non-corrosive pressure regulator to facilitate flow of Carbogen gas with ease.
*Cover on the outer body of the apparatus that can be opened and closed allow for the adjustment of Carbogen flow and pressure control.
*Front opening of the apparatus for easy replacement and egress of the cylinder.
*A humidifier/nebuliser for humidifying the gas before inhalation to prevent dryness of air passage and complications arising thereof.
*Good fit , double valve silicon breathing mask to prevent wastage of gas and comfortable to wear and take off.
*Provision of a spanner for adjusting the valve head for pressure control.

Physical Characteristics
*The height of the trolley is 1145 mm approximately.
*The total weight of the apparatus with the cylinder is 37 kg approximately (18 kg cylinder wt).
*The width of the trolley without the handle is 300 mm approximately.
*The width of the trolley with handle is 450 mm approximately.

*Attachments to fix start/stop valve and placing of nebuliser.
*Wheels for transportation.
*Handle for easy manoeuvrability.

*Easy accessibility of controls and mask/tube outlet to user.
*Push trolley with the placement of the switch for starting the gas supply at an accessible range. The mask outlet of the gas tube is also placed at the accessible range of the user.

Controls, Displays, and Warnings
*Gas output pressure is controlled by the bull-nose valve top spindle rotation. The control can be monitored in the gas pressure meter in suitable units (bars, kg/cm ). After the gas pressure has been set, the knob on the bull-nose valve can adjust the flow. The flow can be monitored with a float in the flow meter in liters per minute.

The user can start and stop the gas supply for his installment using a shut off valve. A ball-type shut off valve has been provided for start/stop the installment of 5 min.

The electronic timer (red and green LED displays for indication of the start and continuation of gas flow, respectively) visible to the user while breathing.
Buzzing from the electronic timer attached to the start/stop valve indicates the end of 5 min duration. The sound pressure level of the buzzer is 60 dB 'A' at the ear of the user in the apparatus's closed condition while it is 65 dB 'A' in equipment's open condition, with predominant frequency at 4 kHz.

Supply System
CO2 and O2 : 5 per cent and 95 per cent, respectively in cylinder.

Potential Applications
Services: Firing ranges, engine room of ships, and for ground crew of the Air Force.

Civil: Industry, machine rooms, airports and traffic police.

Medical/therapeutic applications: Management of sudden sensorineural hearing loss, as adjuvant to radiation therapy in cancer, in alcohol withdrawl, and cigarette smokers.