Shubha Venkatesha Iyengar has been conferred the Padma Shri, India’s fourth-highest civilian award, in recognition of her contributions to aerospace engineering and aviation safety technologies. The award was announced as part of the 2026 Republic Day honours and acknowledges her role in the development of indigenous aviation weather and runway visibility systems.
Iyengar spent more than four decades at the National Aerospace Laboratories (NAL), where she served as Distinguished Scientist and headed the Airport Instrumentation division. In an official statement announcing the awards, the Government of India cited her leadership in the design and deployment of systems that support safe aircraft operations under adverse weather conditions.
A key contribution of Iyengar’s career was her role in leading the development of the Drishti Transmissometer, an indigenous runway visibility measuring system. The technology provides real-time Runway Visual Range (RVR) data to pilots and air traffic controllers, supporting decision-making during take-offs and landings in low-visibility conditions. Prior to the introduction of Drishti, Indian airports depended largely on imported transmissometers for such measurements.
The Drishti system was developed to comply with standards set by the International Civil Aviation Organization and the World Meteorological Organization, while being produced at significantly lower cost than comparable imported equipment. According to NAL, the system is capable of operating reliably in dense fog, heavy rainfall and dust storm conditions, which are common operational challenges at several Indian airports.
The technology measures visibility ranging from below 25 metres to more than 2,000 metres, enabling its use across CAT I, CAT II and CAT III landing operations. Its deployment has been aimed at improving operational continuity by reducing flight delays and diversions during periods of poor visibility, particularly during winter fog conditions in northern India.
As of early 2026, the Drishti Transmissometer had been installed at more than 100 locations across the country, including major civilian international airports and multiple Indian Air Force bases. Indira Gandhi International Airport in New Delhi was the first airport in India to be fully equipped with the indigenous system across all its runways.
From a technical perspective, the system operates using a 30-metre baseline between the transmitter and receiver units and incorporates photopically corrected sensors along with field-programmable gate array controllers to process atmospheric attenuation data. It also features dual-mode communication through Wi-Fi and landline connectivity, allowing for remote monitoring of system health from a central facility in Bengaluru.
In 2020, NAL entered into a licensing agreement with Central Electronics Limited to enable large-scale manufacturing and commercial deployment of the Drishti system. The arrangement was intended to support wider adoption of the technology across India’s civil and defence aviation infrastructure.
The National Aerospace Laboratories is a constituent laboratory of the Council of Scientific and Industrial Research and is engaged in research and development in aerospace systems, materials and instrumentation.
