The runway visibility is a critical weather parameter in ensuring safe aircraft landings & take-off operations, making visual-range assessment systems mandated for every airport. For decades, India had long relied on imported visibility measurement systems, which were prohibitively expensive and lacked the essential provision for local use. This intrigued CSIR-NAL to commence R&D in 2010 to develop an exact, cost-effective, and fully indigenous solution. The resultant was Drishti, an innovative home-grown transmissometer, and the prototype had the opportunity to be installed at IGI Airport, New Delhi, for rigorous evaluation in the same year. After its successful validation by the nation’s sole meteorological authority, the India Meteorological Department (IMD), the first commercial Drishti system was deployed in 2011 at the same IGI Airport, New Delhi, marking the beginning of its R&D mandate.
Breaking Barriers
Developing an indigenous transmissometer from an entirely new concept, meeting the stringent stipulations of the International Civil Aviation Organisation (ICAO) and the World Meteorological Organisation (WMO) was a highly challenging endeavour. Apart from its fundamental technical challenges, the system must be engineered to endure our nation’s diverse weather.
Any transmissometer deployed for airport operations needs mandatory operational requirements for continuous operation with uninterrupted round-the-clock availability. CSIR-NAL’s R&D must innovate across optical design, signal processing, environmental sealing, and maintenance-free architecture to satisfy this stringent requirement, ensuring uncompromised reliability in the most challenging operational conditions.
Cutting-edge Design & Technical Excellence
Drishti, which is installed along the runway, has a light transmitter and a light detecting receiver. In contrast, the transmitter emits a collimated beam with spectral characteristics matching runway lights. At the same time, the receiver, embracing a photopically-corrected optical receiver, captures & analyses the attenuated signal to compute visibility. With adaptive baselines (15–150 metres) as per ICAO/WMO, the system guarantees adaptability for diverse runway setups. Built on an industry-standard FPGA platform, Drishti embraces a plethora of innovations in it, to name a few: Miniaturised cum high-precision optics for optimum collimation, electronic modulation & synchronous demodulation for enhanced signal-to-noise ratio, Dual communication connectivity (Landline & Wi-Fi) from runway to ATC for data redundancy, Remote web-based accessibility for real-time data and health monitoring. Designed with virtual Instrumentation, modular hardware & software, and weatherproof IP65 enclosures to exclusively suit Indian tropical weather conditions, Drishti is built to last even in extreme climatic conditions, from scorching summers to freezing winters. In addition, Drishti embraces the highly ICAO-mandated frangibility with an additional feature of an eco-friendly mechanical pole. Drishti’s pivotal measurement capabilities are RVR of 25 to 2000 metres & MOR of 4–10,000 metres, which completely suffice the compatibility for all sorts of airport categories — CAT I, CAT II, CAT III A & III B.
India’s Choice for Aviation Safety
Drishti — the nation’s one & only transmissometer, is more than an instrument; it is a statement of the nation’s technological self-reliance. Conceived, designed, and developed by CSIR-NAL, Drishti has redefined aviation safety in India by offering unparalleled precision at just one-third the cost of its (imported) adversaries. After its stupendous performance delivered during the extreme fog conditions at IGI Airport during the winter 2011–12, CSIR-NAL’s Drishti gained the confidence of the meteorologists for its accuracy and reliability.
In 2014, CSIR-NAL & IMD signed a landmark partnership agreement. Under this mutual arrangement, CSIR-NAL will develop Drishti in its laboratory, and IMD will procure & deploy Drishti systems for their usage nationwide. This breakthrough agreement paved the way for Drishti to expand from the nation’s capital to most airports nationwide to serve its customers. Today, over 51 Drishti systems operate seamlessly across 21 civilian airports — a living testament to indigenous innovation dedicated to the highest mandate of all: safeguarding precious human lives in aviation.
From Civil to Defence: Expanding Horizons
Originally, Drishti was developed to address the operational needs of civilian airports. However, Drishti’s adaptability to any terrain and its reliability & accuracy attracted the Indian defence to its usage. The proven round-the-clock operation in diverse and often extreme weather conditions made it an ideal solution for mission-critical air operations. These features categorically attributed Drishti to achieving a towering success in defence deployments, surpassing civilian installations. Around 120 Drishti transmissometers are functioning across 36 Indian Air Force airfields, 4 Indian Navy airbases, 1 Indian Army airfield, and 1 HAL airbase.
Where Innovation Meets Recognition
Drishti is considered a true emblem of India’s technological self-reliance in aviation meteorology and resonates the nation’s currently echoing visions “Atmanirbhar Bharat” & “Viksit Bharat 2047”. This indigenous marvel holds one patent, one trademark, and a whopping 14 copyrights, underscoring its originality and innovation. Besides, Drishti Technology is decorated with many coveted awards, to name a few, the CSIR Technology Award, Aeronautical Society of India Award, CSIR-NAL Best Innovation Award, IETE Diamond Jubilee Corporate Award, NRDC Meritorious Invention Award, IESA Technovation Award, and the Make in India Award. All these recognitions not only endorse Drishti’s technical distinction but also underscore its pivotal role in strengthening the nation’s aviation safety.
The Road Forward
Drishti technology has been transferred to M/s Central Electronics Limited (CEL) and M/s Tata Advanced Systems Limited (TASL) to meet the nation’s burgeoning demand. Drishti’s Technology Transfer to industrial partners is to significantly increase its production and seamlessly cater to the growing requirements emanating from different quarters. Following the Technology Transfer, Tata Advanced Systems Limited (TASL) developed & successfully deployed 70 Drishti systems at Defence airbases, HAL & Private airfields. Likewise, CEL, on the other hand, contributed to installing three systems at both Civilian and Defence airstrips. It is very sure that Drishti will capture a sizeable share of the global market for its legacy of field-proven reliability, a decisive cost advantage, and adherence to ICAO and WMO stipulations through the ToT Partners. The next episode for Drishti is shaped by futuristic R&D — pioneering next-generation sensing & AI-based trend forecasting. By delivering unmatched precision at nearly one-third the global cost, Drishti is poised to redefine runway safety worldwide and remain an enduring symbol of India’s innovation & self-reliance.
