Sujata Dhar

Special Mention of Research Activities

The following articles are solely written on the research activities carried out by me and my professors.

• Dainik Jagran (National Issue) article on the occasion of Technology Day on 11th May 2020.

https://www.jagran.com/uttar-pradesh/kanpur-city-iit-kanpur-scientists-will-find-out-why-the-pace-of-the-earth-slowed-down-37-seconds-jagran-special-20260529.html

• Dainik Jagran article on 4th March 2020.

https://www.jagran.com/uttar-pradesh/kanpur-city-iit-kanpur-will-forecast-earthquake-storm-and-other-major-disasters-20083211.html

Experience

1. Granted DAAD Project on " Effect on Earth Orientation Parameter and International Terrestrial Reference Frame by having GNSS and VLBI sites in India" with collaboration with TU Berlin and GFZ Potsdam. (Nov 2020 - Nov 2022).

2. Working as student coordinator in all research and organizational activities of National Centre for Geodesy (NCG) established by DST at IIT Kanpur (2019 onwards).

3. Student member in International Association of Geodesy (IAG).

4. Indian member in European Geo sciences Union (EGU).

Education

Secondary Education

Graduated SSC from Delhi Public School, Bhilai (DPS Bhilai) in CBSE Board with

• 9.6 / 10 CGPA in 2011

Graduated HSC from Delhi Public School, Bhilai (DPS Bhilai) in CBSE Board with subjects: Physics, Chemistry, Mathematics, Biology with

• 93.2% in 2013

Bachelor's Degree

Graduated from National Institute of Technology, Raipur (NIT Raipur) in B.Tech, Civil Engineering with

• 9.45 / 10 CPI in 2017

• Received Silver medal of the batch 2013-2017

Doctor of Philosophy

Joined PhD degree programme in Indian Institute of Technology, Kanpur (IIT Kanpur) in 2017

• Received Institute Assistantship in Geoinformatics, Civil Engineering Department, IIT Kanpur

• Received PMRF Fellowship for PhD in July, 2018.

• 8.3 / 10 CPI till now

Background and Motivation for my PhD thesis

A reference frame is the practical realization of a reference system. It provides an indispensable standard against which the changes and variability of earth dynamics are quantified and properly referenced. Reference frame stands strong with the support of three pillars- Earth orientation, Gravity field and geokinematics. Earth orientation is the change of the earth’s axis direction relative to space (celestial pole offsets) and earth’s crust (pole coordinates and variation in LOD). Earth is not static; the internal and external dynamical forces causes the earth’s rotation to change. Hence, by monitoring earth rotation we can monitor those forces.

The main motivation for our efforts to undertake this research work are as follows: -

1. India lacks in space geodetic techniques, with no VLBI, SLR, DORIS sites and only two GNSS in the southern part. Therefore, there is no contribution of India for the precise contribution of EOPs and consequent realization of ITRF (International Terrestrial Reference Frame) and ICRF (International Celestial Reference Frame). Due to this there is a huge gap globally, i.e. the Indian sub-continent which extends longitudinally from 60°E to 90° E.

2. We believe that the geographically well distributed stations in India will help in achieving greater precision in the international effort to compute EOPs and realize consistent ITRF and ICRF. By this research, we will be improving the geodetic infrastructure of the country and then, the movement of Indian tectonic plate can be monitored properly.

3. Since, GNSS data as well the VLBI will be available in our campus itself, it will help me to bring beginning in this area, to be continued by the upcoming geodetic researchers of the country.

Impact of my research

A well-defined reference frame helps to monitor long term movements like Earth’s crust movements, plate tectonics, redistribution of fluids on or near the surface, etc. All these scientific applications depend on a truly global reference system that only geodesy can provide. The following are the target beneficiaries: -

1. This will help to improve Indian geodetic infrastructure and research activities related to Earth studies will be benefitted. Major stakeholders will be NGRI, GSI, MOES, ISRO, SoI and DRDO.

2. Great impact on the Indian geodetic community as this particular research topic is taken up in India for the first time. This will encourage and open opportunities for young geodesists working in this area.

3. Results from this research proposal will be influential in efficient, cost-effective and proper planning of geodetic infrastructure for India. Owing to its importance, this day or tomorrow, planned geodetic infrastructure cannot be averted for Indian tectonic plate.

Novelty and Scope of my research

20 years ago, India used to send data for earth rotation parameters by measurement from optical instrument. But that was stopped as the precision of optical instrument was far less than the precision of then determined earth rotation or orientation parameters. From that time, India’s contribution towards computation of ERP/EOP and ITRF has been zero or negligible.

To relate instantaneous coordinates of satellites or quasars to the Earth fixed systems requires knowledge of Earth orientation parameters (EOP). The ITRF is the metrological framework that has become indispensable for Earth science applications and for satellite navigation.

It is easy to take for granted the work that goes into producing a precise and reliable ITRF despite the countless research that relies on it. The research deliverables of this project will be taken for the first time in India. The results will provide base to develop the geodetic infrastructure of the country mainly VLBI and GNSS. Co-located site of GNSS-VLBI will be the first of its kind in India and will increase the contribution of Indian perspective in the computation of the precise EOP and realization of ITRF.