National Remote Sensing Day is celebrated every year on the 12th August, on the Occasion of birth anniversary of Prof. Vikram Sarabhai, A Great renowned Indian Scientist and physicist and a great innovator who established the Indian Space programme at 1969 and widely regarded as the “Father of India’s Space Programme”.
This Year, as we mark the 101th birth anniversary of Dr. Vikram Sarabhai, We as Geo-Spatial Community are excited to celebrate the National Remote Sensing Day by spreading the word of Remote Sensing and Space Science with special emphasis to its application for environment and society and spread awareness on harnessing the use of remote sensing technologies for the environment and society.
Dr. Sarabhai emphasize the importance of a space programme in his quote: –
“There are some who question the relevance of space activities in a developing nation. To us, there is no ambiguity of purpose. We do not have the fantasy of competing with the economically advanced nations in the exploration of the moon or the planets or manned space- flight. But we are convinced that we are to play a meaning full role nationally, and in the community of nations, we must be second to none in the application of advanced technologies to the real problems of man and society”. – Vikram Sarabhai
Now, Let’s understand the Word ‘Remote Sensing’
Remote sensing is the process of detecting and monitoring the physical characteristics of an area by measuring its reflected and emitted radiation at a distance without being a physical contact typically from satellite or aircrafts.
In other word, Remote sensing is an Art and Science of collecting information about object, area and phenomenon or the science of obtaining information about object or an area from a distance.
Is Remote Sensing a Science?
Remote sensing is a tool or techniques similar to other scientific discipline like mathematics. Which uses sophisticated sensors to measure the amount of electromagnetic radiation (EMR) existing an object or geographic area and then extracting valuable and quantitative information from the remotely sensed data using mathematically and statistically based algorithms is a scientific activity.
(Source: John R, Jensen, 2007)
The Diagram represents the interaction and relationship of GI-Sciences and their relation to Physical science, Social Science and Biological science with mathematics and logics.
Is Remote Sensing an Art?
The interpretation of Image is not only limited to Scientific knowledge but all of the experiences that a person has obtained in a lifetime. The alliance of scientific knowledge with real world experience allows the interpreter to develop interrogative thumb rules to extract information from the remotely sensed data.
Thus, Remote sensing image interpretation can be understanding in both ways as an art and Science and can be defined as art and science for extracting information from remotely sensed data.
Indian Satellite: The satellite is an artificial object which has been deliberately put into space for different purposes such as remote sensing, weather forecasting, image mapping, education, and research. India has been successfully launching satellites of various types since 1975. The Indian Space Research Organization (ISRO) is considered is the sole space agency of India and was established in 1969.
There are number of Indian satellite available launched in different years for the specific purposes and application.
Table 1: List of Indian Satellites, Launch Year (1975-2020) and their importance
|S.No.||Satellite||Launch year||Importance||S.No||Satellite||Launch year||Importance||S.No.||Satellite||Launch year||Importance|
|1||Aryabhata||1975||First Indian Satellite. It gave valuable technological know-how about satellites.||35||INSAT-3C||2001||Designed to provide continuity of the services of INSAT-2C and augment the existing INSAT capacity for communication and broadcasting.||69||GSAT-7||2013||Advanced multi-band communication satellite dedicated for military purpose|
|2||Bhaskara-I||1979||First experimental remote sensing satellite that carried TV and microwave cameras.||36||Kalpana-1 (METSAT)||2002||First meteorological satellite built by Indian Space Research Organisation.||70||Mars Orbiter Mission (MOM)||2013||India’s first Mars orbiter|
|3||Rohini Technology Payload||1979||The first Indian launch vehicle.||37||INSAT-3A||2003||Multipurpose satellite for communication, broadcasting, and meteorological services along with and Kalpana-1 and INSAT-2E.||71||GSAT-14||2014||Geostationary communication satellite|
|4||Rohini RS-1||1980||India’s first indigenous satellite launch.||38||GSAT-2||2003||Experimental satellite for the 2nd developmental test flight of GSLV.||72||IRNSS-1B||2014||Second satellite in the Indian Regional Navigation Satellite System|
|5||Rohini RS-D1||1981||Launched by the first developmental launch of SLV-3 and carried a solid-state camera.||39||INSAT-3E||2003||Communication satellite to augment the existing INSAT System||73||IRNSS- 1C||2014||Third satellite in the Indian Regional Navigation Satellite System|
|6||Ariane Passenger Payload Experiment||1981||First experimental communication satellite.||40||RESOURCESAT-1 (IRS-P6)||2003||Most advanced Remote Sensing Satellite||74||GSAT-16||2014||communication satellite|
|7||Bhaskara-II||1981||Second experimental remote sensing satellite.||41||EDUSAT (GSAT-3)||2004||India’s first satellite exclusively for education||75||IRNSS-1D||2014||Fourth satellites in the Indian Regional Navigation Satellite System|
|8||INSAT-1A||1982||First operational multipurpose communication and meteorology satellite.||42||HAMSAT||2005||Microsatellite for radio services to national and international community||76||GSAT-6||2014||Communication satellite|
|9||Rohini RS-D2||1983||Carried a smart sensor camera.||43||CARTOSAT-1||2005||Earth observation satellite||77||Astrosat||2015||India’s first dedicated multi-wavelength space Observatory|
|10||INSAT-1B||1983||Very successful. Revolutionized TV, radio, and telecommunications.||44||INSAT-4A||2005||Direct-to-home(DTH) TV broadcasting||78||GSAT-15||2015||Communications satellite, carries GPS Aided GEO Augmented Navigation (GAGAN) payload|
|11||SROSS-1||1987||No remarkable achievement.||45||INSAT-4C||2006||Geosynchronous communications satellite||79||IRNSS-1E||2016||Fifth satellite in the Indian Regional Navigation Satellite System|
|12||IRS-1A||1988||Earth observation satellite.||46||CARTOSAT-2||2007||Remote sensing satellite-carrying panchromatic camera||80||IRNSS-1F||2016||Sixth satellite in the Indian Regional Navigation Satellite System|
|13||SROSS-2||1988||No remarkable achievement.||47||SRE-1 (Space Capsule Recovery Experiment)||2007||Test satellites to show an orbiting platform for performing tests in microgravity conditions||81||IRNSS-1G||2016||Seventh and final satellite in the Indian Regional Navigation Satellite System|
|14||INSAT-1C||1988||No remarkable achievement.||48||INSAT-4B||2007||Similar to INSAT-4A||82||CARTOSAT-2C||2016||Earth observation remote sensing satellite|
|15||INSAT-1D||1990||Still operational.||49||INSAT-4CR||2007||Identical to INSAT-4C||83||INSAT-3DR||2016||An advanced meteorological satellite of India configured with an imaging System and an Atmospheric Sounder.|
|16||IRS-1B||1991||Earth observation satellite.||50||CARTOSAT-2A||2008||Similar to CARTOSAT-2||84||SCATSAT-1||2016||Miniature satellite to give climate anticipating, tornado expectation, and tracking services to India.|
|17||SROSS-C||1992||Carried gamma-ray astronomy and aeronomy payload.||51||IMS-1||2008||Low-cost micro-satellite||85||CARTOSAT-2D||2017||The highest number of satellites (104 satellites) launched by a single launch vehicle.|
|18||INSAT-2DT||1992||It was launched as Arabsat 1C.||52||Chandrayaan-1||2008||India’s first lunar probe||86||CARTOSAT- 2F||2018||CartoSat-2F is the 6th satellite in the Cartosat series to be built by ISRO.|
|19||INSAT-2A||1992||First satellite in the second-generation Indian-built INSAT-2 series.||53||RISAT-2||2009||Radar imaging satellite||87||MICROSAT- TD||2018||This satellite is a technology demonstrator and the forerunner of future satellites.|
|20||INSAT-2B||1993||Second satellite in INSAT 2 series.||54||ANUSAT||2009||Research Microsatellite developed by Anna University||88||INS -1C||2018||This is the third satellite in the Indian Nanosatellite series, which carried a Miniature Multispectral Technology Demonstration (MMX-TD) Payload.|
|21||IRS-1E||1993||Earth observation satellite.||55||Oceansat-2||2009||Collects oceanographic, coastal and atmospheric data||89||GSAT- 6A||2018||This satellite is a high power S-band communication satellite configured around I-2K bus.|
|22||SROSS-C2||1994||No remarkable achievement.||56||GSAT-4||2010||Communications satellite technology which failed during the mission||90||IRNSS -1I||2018||This satellite is the 6th in the series and facilitates GPS navigation.|
|23||IRS-P2||1994||Earth observation satellite. Launched by second developmental flight of PSLV.||57||CARTOSAT-2B||2010||Earth observation/remote sensing satellite.||91||GSAT-29||2018||This satellite facilitates high-throughput communication.|
|24||INSAT-2C||1995||Still in operation. Has television outreach beyond Indian boundaries.||58||GSAT-5P /INSAT-4D||2010||Mission failed||92||HySYS||2018||It facilitates Hyperspectral imaging services for agriculture, forestry, and military applications.|
|25||IRS-1C||1995||Earth observation satellite.||59||RESOURCESAT-2||2011||Remote-sensing satellite||93||ExseedSat-1||2018||1st privately funded satellite of India.|
|26||IRS-P2||1994||Earth observation satellite.||60||INSAT-4G||2011||C-band communication satellite||94||GSAT-11||2018||Heaviest spacecraft of India.|
|27||IRS-P3||1996||Earth observation satellite.||61||Youthsat||2011||Indo-Russian stellar and atmospheric satellite||95||GSAT-7A||2018||Facilitates services for Indian Army and Air Force.|
|28||INSAT-2D||1997||Inoperable since 1997-10-04 due to power bus anomaly.||62||GSAT-12||2011||communication satellite||96||Microsat-R||2019||This satellite facilitates Earth imaging for defense purposes.|
|29||IRS-1D||1997||Earth observation satellite.||63||Megha-Tropiques||2011||Indo-French collaborative effort to research on water cycle in the atmosphere||97||KalamSAT-V2||2019||It is the world’s lightest satellite.|
|30||INSAT-2E||1999||Multipurpose communication and meteorological satellite.||64||RISAT-1||2012||First indigenous all-weather Radar Imaging Satellite||98||GSAT-31||2019||This is a high-throughput Telecommunication Satellite.|
|31||IRS-P4 OCEANSAT||1999||Earth observation satellite carrying a Multifrequency Scanning Microwave Radiometer (MSMR)and an Ocean Colour Monitor (OCM).||65||GSAT-10||2012||advanced communication satellite||99||EMISAT||2019||This facilitates Electromagnetic intelligence to track any enemy radars for the IAF.|
|32||INSAT-3B||2000||Multipurpose communication satellite.||66||SARAL||2013||Mission for oceanographic studies||100||Chandrayaan-2||2019||India’s second lunar exploration mission.|
|33||GSAT-1||2001||Experimental satellite for the first developmental flight of GSLV-D1.||67||IRNSS-1A||2013||Seven spacecraft constituting the IRNSS space segment||101||Cartosat-3||2019||Cartosat-3 is one of the optical satellites with the highest resolutions in the world.|
|34||Technology Experiment Satellite (TES)|
|2001||Experimental satellite to test new reaction control system, high-torque reaction wheels, and attitude and orbit control system.||68||INSAT-3||2013||Meteorological Satellite||102||GSAT-30||2020||GSAT-30 is the 41st communication satellite launched by ISRO to replace INSAT-4A. It provides advanced telecommunication services to the entire Indian subcontinent.|
Overview of remote sensing in environmental studies:
The remotely sensed data provide valuable information for mapping and monitoring the environmental processes since long time. There are number of remotely sensed data available from different sensors of various platform with a wide range spatial-temporal, radiometric and spectral resolution provides the best source of data for wider applications and studies. There are number of application where remotely sensed data can be utilized as primary input such as environmental mapping and monitoring, Hydrological modelling, watershed mapping, management and development, energy and water flux estimation, urban modelling, drought predictions, climate change etc.
A State of art of satellite sensors widely used in environmental application and natural resource management. These Sensors provides spatial and temporal data in a wide range of scale, radiometry, numbers of band, band width and provide distinct advantage of consistency of data, synoptic coverages, global reach, cost per unit area, repeatability, precision and accuracy.
Application of Remote Sensing in various domains
There are many different fields of study where Remote sensing techniques and Remotely sensed data is extensively utilized like environment mapping and monitoring and Agriculture etc. there is also other diversity of application where this techniques and associated data can be potentially utilized to extract meaningful information of the geographical area.
The Majority of application has been focused on natural environments over the past decades. The Application of remote sensing in urban domain is comparatively new and gaining more research interest in the geospatial community with the advent of high-resolution imagery and more capable techniques and has application in socio economic sectors. There are numbers of techniques developed for mapping and monitoring the Urbanization and for sustainable planning and development.
The Role of remote sensing in understanding hydrological processes and fluxes across different spatial and temporal can be tremendous, if appropriate spatial and temporal resolution data are available under ranges of bands. There are three main categories mapping of watersheds and features, indirect hydrological parameter estimation and direct estimation of hydrological variables. Similarly, there are other application of soil, water and drought monitoring, agriculture, forest ecosystem, Snow and Glacier, climate change and others respectively where remote sensing techniques and datasets at different resolution is extensively utilizing for the specific purposes and the investigations.
Future Direction of Remote Sensing
The Advancement made in space-borne remote sensing in the past years has been phenomenal which leads to increasing several innovations in multiple directions. The Future development and advancement lead to availability of data from multiple sensors with wide array of spatial, spectral and radiometric characteristics which will be certainly available from multiple sources. Second, micro satellite with capability in collecting data for specific geographic location are likely to become more attractive and gain special interest among researchers and other, the advancement in hyperspectral and hyperspatial brings new challenges in data mining processing and backups and retrieval. Thus, the Future advancement in remote sensing brings more challenges, innovations, wide coverage data availability, developments and applicability in diversity of application will be prime interest among researchers or scientific communities.
Jensen J.R. Remote Sensing of the Environment: An Earth Resource Perspective. 2nd Ed. Prentice-Hall, Inc.; Upper Saddle River, NJ: 2000. p. 544.
Lillesand, T.M. Kiefer, R.W., 2002, Remote sensing and image interpretation, Fourth edition, pp.192-193.
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