ISRO, IAF may have to pay for getting precision timings

Plan is to charge Rs 1 crore per location where the service is provided, an NPL official said

The importance of time is instilled and etched in the universe. Many space and aeronautical agencies, railways and banks, etc, depend upon time precision for smooth operations. Every satellite launch and flight operation needs to have precise, accurate timing that is at par with the global standards.

Till now, the Indian Space Research Organisation (ISRO) and the Indian Air Force (IAF) were receiving accurate timings free of cost, thanks to the National Physical Laboratory (NPL). Now, Indian Space Research Organisation and Indian Air Force may have to pay the government for getting accurate timings on par with the global standard for various activities like launch of satellites and flight operations.

So far, the National Physical Laboratory (NPL) has been extending the service free of cost to ISRO, IAF, Indian Railways, State Bank of India and several other agencies.

The move is aimed at ramping up NPL’s chronometer infrastructure to match global standards.

The NPL, one of the oldest laboratories in the country, maintains five atomic clocks, all synchronised with the atomic clock of the International Bureau of Weight and Measure, France. There are 300 such high precisions clocks across the globe linked to the Bureau in France.

The accuracy of NPL’s chronometer is (+/-) 20 nano seconds, whereas the global accuracy standard is as low as (+/-) 5 nano seconds.

The NPL under the premier Council for Scientific and Industrial Research (CSIR) held separate meetings with ISRO and IAF last week, conveying its plans to charge them for the services it offers.

The plan is to charge Rs 1 crore per location where the service is provided, an NPL official said.

Discussions are on to either issue a notification or bring in a legislation in this regard.

The NPL will also hold talks with its other customers like State Bank of India, India Railways and the Department of Telecommunications to discuss the issue.

The high precision timing has impact on the lives of people as services by agencies like ISRO, banks, railways and telecom operators use NPL services.

Agencies like ISRO trust the accurate timings during the launch of a satellite. In case of ISRO, timings are sent via satellite. Banks like SBI also subscribe to NPL services as high precision timing is required during forex transactions.

The CSIR, which comes under the Ministry of Science and Technology, plans to have 18 atomic clocks, a norm followed by all developed countries to maintain accuracy. Since several parts of north India fall under seismic zones, it also plans to develop a laboratory in south India.

“At present, we have five atomic clocks and we will get five more by the end of the year. But this is not enough considering the growing demand for accurate timings by subscribers for which we need to maintain quality.

“Secondly, research and developing the system has to be a continuous process to keep in pace with the global standard,” said NPL Director AK Aswal.

He said that under the ‘Dehradun Declaration’ of the CSIR, laboratories have to generate 40 per cent of revenue required on its own.

The NPL also plans to construct a separate building that can accommodate 18-20 atomic clocks and a data centre. This will alone cost Rs 500-600 crore.

“This requires a different kind of building free from any kind of vibration, electro-magnetic disturbances, radiation, humidity and temperature,” said Vijay Narain Ojha, chief scientist and head of Time & Frequency and Electrical & Electronics Meteorology Division.

The upkeep of the existing system is also expensive. The atomic clock requires low temperature without any power fluctuation.

“So, air-conditioners have to be in operation for 365 days a year and 24×7. Maintenance and research also adds to the cost,” Ashish Agarwal, another scientist at in the time and frequency section, said.

Apart from atomic clock, NPL also assists industries, national and other agencies in their developmental tasks by providing precision measurements, calibration, development of devices, processes, and other allied problems related to physics.

About National Physical Laboratory

The National Physical Laboratory of India, situated in New Delhi, is the measurement standards laboratory of India. It maintains standards of SI units in India and calibrates the national standards of weights and measures.

History of measurement systems in India

One of the most ancient texts of India, Manusmriti, describes among the duties of the king: The king should examine the weights and balances every six months to ensure true measurements and to mark them with the royal stamp.Manusmriti, 8th Chapter, Shloka 403. In the Harappan era, which is nearly 5000 years old, one finds excellent examples of town planning and architecture. The sizes of the bricks were the same all over the region. In the time of Chandragupta Maurya, some 2400 years ago, there was a well – defined system of weights and measures. The government of that time ensured that everybody used the same system. In the Indian medical system, Ayurveda, the units of mass and volume were well defined.

The measurement system during the time of the Mughal emperor, Akbar, the gaz was the measure of length. The gaz was widely used till the introduction of the metric system in India in 1956. During the British period, efforts were made to achieve uniformity in weights and measures. A compromise was reached in the system of measurements which continued till India’s independence in 1947. After independence in 1947, it was realized that for fast industrial growth of the country, it would be necessary to establish a modern measurement system in the country. The Lok Sabha in April 1955 resolved : This house is of the opinion that the Government of India should take necessary steps to introduce uniform weights and measures throughout the country based on metric system.

History of the National Physical Laboratory, India

The National Physical Laboratory, India was set up in 1900) is one of the earliest national laboratories set up under the Council of Scientific & Industrial Research. Jawaharlal Nehru laid the foundation stone of NPL on 4 January 1947. Dr. K. S. Krishnan was the first Director of the laboratory. The main building of the laboratory was formally opened by Former Deputy Prime MinisterSardar Vallabhbhai Patel on 21 January 1950. Former Prime Minister Indira Gandhi, inaugurated the Silver Jubilee Celebration of the Laboratory on 23 December 1975.

NPL Charter

The main aim of the laboratory is to strengthen and advance physics-based research and development for the overall development of science and technology in the country. In particular its objectives are:

To establish, maintain and improve continuously by research, for the benefit of the nation, National Standards of Measurements and to realize the Units based on International System (Under the subordinate Legislations of Weights and Measures Act 1956,reissued in 1988 under the 1976 Act). To identify and conduct after due consideration, research in areas of physics which are most appropriate to the needsof the nation and for advancement of field

To assist industries, national and other agencies in their developmental tasks by precision measurements, calibration, development of devices, processes, and other allied problems related to physics.

To keep itself informed of and study critically the status of physics.

Maintenance of standards of measurements in India

Each modernized country, including India has a National Metrological Institute (NMI), which maintains the standards of measurements. This responsibility has been given to the National Physical Laboratory, New Delhi.


The standard unit of length, metre, is realized by employing a stabilized Helium – Neon laser as a source of light. Its frequency is measured experimentally. From this value of frequency and the internationally accepted value of the speed of light (299,792,458 metres/second), the wavelength is determined using the relation:

Wavelength = Velocity of light / frequency

The nominal value of wavelength, employed at NPL is 633 nanometer. By a sophisticated instrument, known as an optical interferometer, any length can be measured in terms of the wavelength of laser light.

The present level of uncertainty attained at NPL in length measurements is ± 3 × 10−9. However in most measurements, an uncertainty of ± 1 × 10−6 is adequate.


The Indian national standard of mass, kilogramme, is copy number 57 of the international prototype kilogram supplied by the International Bureau of Weights and Measures (BIPM : French – Bureau International des Poids et Mesures), Paris. This is a Platinum Iridium cylinder whose mass is measured against the international prototype at BIPM. The NPL also maintains a group of transfer standard kilograms made of non – magnetic stainless steel and nickel – chromium alloy.

The uncertainty in mass measurements at NPL is ± 4.6 × 10−9.


The national standard of time interval, second as well as frequency, is maintained through four parameters, which can be measured most accurately. Therefore, attempts are made to link other physical quantities to time and frequency. The standard maintained at NPL has to be linked to different users. This process, known as dissemination, is carried out in a number of ways. For applications requiring low levels of uncertainty, there is satellite based dissemination service, which utilizes the Indian national satellite, INSAT. Time is also disseminated through TV, radio, and special telephone services. The caesium atomic clocks maintained at NPL are linked to other such instituted all over the world through a set of global positioning satellites.


The unit of electric current, ampere, is realized at NPL by measuring volt and Ohm separately.

The uncertainty in measurement of ampere is ± 1 × 10−6.


The standard of temperature is based on the International Temperature Scale of 1990 (ITS – 90). This is based on the assigned temperatures to several fixed points. One of the most fundamental temperatures of these is the triple point of water. At this temperature, ice, water and steam are at equilibrium with each other. This temperature has been assigned the value of 273.16 kelvin. This temperature can be realized, maintained and measured in the laboratory. At present temperature standards maintained at NPL cover a range of 54 to 2,473 kelvin.

The uncertainty in its measure is ± 2.5 × 10−4.


The unit of luminous intensity, candela, is realized by using an absolute radiometer. For practical work, a group of tungsten incandescent lamps are used.

The level of uncertainty is ± 1.3 × 10−2.


Experimental work has been initiated to realize mole, the SI unit for amount of substance


The NPL does not maintain standards of measurements for ionizing radiations. This is the responsibility of the Homi Bhabha Atomic Research Centre, Mumbai.

Calibrator of weights and measures

The standards maintained at NPL are periodically compared with standards maintained at other National Metrological Institutes in the world as well as the BIPM in Paris. This exercise ensures that Indian national standards are equivalent to those of the rest of the world.

Any measurement made in a country should be directly or indirectly linked to the national standards of the country, For this purpose, a chain of laboratories are set up in different states of the country. The weights and measures used in daily life are tested in the laboratories and certified. It is the responsibility of the NPL to calibrate the measurement standards in these laboratories at different levels. In this manner, the measurements made in any part of the country are linked to the national standards and through them to the international standards.

The weights and balances used in local markets and other areas are expected to be certified by the Department of Weights and Measures of the local government. Working standards of these local departments should, in turn, be calibrated against the state level standards or any other laboratory which is entitled to do so. The state level laboratories are required to get their standards calibrated from the NPL at the national level which is equivalent to the international standards.


NPL is also involved in research. One of the important research activities undertaken by NPL is to devise the chemical formula for the indelible ink which is being used in the Indian elections to prevent fraudulent voting. This ink, manufactured by the Mysore Paints and Varnish Limited is applied on the finger nail of the voter as an indicator that the voter has already cast his vote.

NPL also have section working on development of biosensors. Currently the Biomedical Instrumentation section is headed by Dr. A. M. Biradar and section is primarily focusing on development of sensor for cholesterol measurement and microfluidic based biosensors.

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