The launch and commissioning of IRS-1A, the first operational Indian Remote Sensing (IRS) Satellite, in 1988 marked the beginning of operational remote sensing data and services in India. By that time, India had established an institutional mechanism in the country, known as the National Natural Resources Management System (NNRMS), to drive the country to operationally use the data from these satellites. India has since launched a slew of IRS satellites. The Indian Space Research Organisation (ISRO) currently operates four satellite series: Resources, RISAT, Cartosat, and Oceansat. INSAT-3D/3DR satellites provide meteorological services. In this article, we will discuss in detail regarding IRS Systems and Remote Sensing Applications which will be helpful for UPSC exam preparation.

Types of IRS Satellites

1) IRS-1A and IRS-1B

• IRS-1A and IRS-1B were both launched in 1988 and 1991.
• These satellites were designed primarily for remote sensing applications such as cartography, land use mapping, and forestry.
• They had a spatial resolution of 36 metres and a 148-kilometer swath width.

2) IRS-1C and IRS-1D

• IRS-1C and IRS-1D were both launched in 1995 and 1997.
• With a spatial resolution of 5.8 metres and a swath width of 140 kilometres, these satellites outperformed their predecessors.
• They were used for a variety of purposes, including mineral exploration, coastal monitoring, and disaster management.

3) Resourcesat-1 Resourcesat-2

• Resourcesat-1 was launched in 2003, followed by Resourcesat-2 in 2011.
• These satellites were designed primarily for resource mapping and management applications such as soil moisture mapping, crop inventory, and forestry.
• They had a swath width of 23 kilometres and a spatial resolution of 5.8 metres.

4) Cartosat-1, Cartosat-2 and Cartosat-3

• Cartosat-1, Cartosat-2, and Cartosat-3, respectively, were launched in 2005, 2007, and 2019.
• These satellites were used for cartography as well as high-resolution imaging.
• The spatial resolution of Cartosat-1 was 2.5 metres, while Cartosat-2 and Cartosat-3 were 1 metre.
• Cartosat-1 data is used to create cartographic maps, update cadastral mapping, and create GIS applications.
• Cartosat-3 also had the ability to capture hyperspectral images.

5) RISAT-1 and RISAT-2

• RISAT-1 and RISAT-2 were both launched in 2009 and 2012.
• These satellites were equipped with synthetic aperture radar (SAR) sensors, which allowed them to capture images of the Earth even when it was cloudy or dark.
• The spatial resolution of RISAT-1 was 3.6 metres, while that of RISAT-2 was 1 metre.

6) Oceansat-1 and Oceansat-2

• Oceansat-1 was launched in 1999, followed by Oceansat-2 in 2009.
• These satellites were used for oceanographic applications such as mapping sea surface temperature, ocean colour, ocean wind vectors, chlorophyll concentrations are measured, phytoplankton blooms monitoring, and atmospheric aerosols and suspended sediments in the water are investigated.

7) Resourcesat-3

• Resourcesat-3, which was launched in 2021, is the most recent addition to India's fleet of remote sensing satellites.
• This satellite is outfitted with cutting-edge sensors capable of capturing images with a spatial resolution of 5.8 metres and a swath width of 120 kilometres.
• The primary application of Resourcesat-3 is for resource mapping and management applications such as crop monitoring, forestry, and water resource management.

8) SARAL

• SARAL, or Satellite with ARgos and ALtiKa, is an ISRO and CNES (Space Agency of France) cooperative altimetry technology mission that was successfully launched on February 25, 2013.
• The overall goals are to assess operational oceanography development, climate understanding, and forecasting capabilities.

List of IRS Satellites

Applications of IRS

1) Applications in Agriculture and Soil

• Cropping pattern mapping;
• Pre- harvest crop area, production and yield estimation;
• Condition assessment;
• Monitoring command areas;
• Compliance monitoring (farming practices) e.g. crop stubble burning;
• Identification of suitable sites for different agricultural practices;
• Mapping of soil characteristics;
• Mapping of soil management practices;
• Mapping of saline soils and monitoring of land reclamation;
• Inventorying and categorization of wastelands; and
• Identification of fishery prospects.

2) Applications in Bio-resources and Environment

• Mapping of forest cover, types, density and species inventory;
• Measurement of biophysical conditions of forest strands;
• Social forestry and agroforestry mapping;
• Biomass estimation;
• Afforestation and deforestation assessment;
• Forest fire surveillance;
• Forest health and vigor monitoring;
• Detailed survey and inventory of the existing bio-resources;
• Environmental impact assessment including pollution (land, water and air);
• Mapping and monitoring of tiger reserves, elephant corridors, biosphere reserves, mangroves and coral reefs;
• Assessment of fuel wood and timber resources; and
• Environmental hazard related studies like zonation and damage assessment (floods, drought, cyclone, landslide, volcano, earthquake etc.)

3) Applications in Geology and Mineral Resources

• Mapping of surfacial deposits and bedrock;
• Lithological and structural mapping;
• Mineral prospecting and exploration; and
• Geo - hazard mapping, monitoring and zonation.

4) Applications in Oceanography

• Identification of potential fishery zones;
• Phytoplankton abundance and habitat assessment;
• Observation of marine pollution and sedimentation and its impact; and
• Assessment of sediment dynamics, tidal fluctuations, sea level changes and coastal circulations.

5) Applications in Water Resources

• Mapping of surface water bodies;
• Identification of potential ground water resources;
• Wetland mapping and monitoring;
• Snow pack and glacial monitoring;
• Ice thickness measurements;
• Rivers, watersheds and ice lake monitoring and modelling;
• Flood mapping and monitoring;
• Monitoring reservoir extends over seasons and irrigation scheduling and flood management; and
• Snowmelt runoff forecasting.

6) Applications in Urban Sector

• Mapping and Land Use Land Cover classification;
• Urban sprawl analysis;
• Identification of illegal encroachment, and constructions;
• Property tax assessment and estimations;
• Transport and urban planning;
• Mapping of utilities and services;
• Population estimation;
• Slum detection and monitoring; and
• Site suitability analysis.

7) Applications in Cartography

• Mapping is an essential component of the resource management process, and mapped information is a common byproduct of the analysis of remotely sensed data from IRS series satellites.
• The Cartosat series is designed specifically for geoengineering mapping and DTM (Digital Terrain Modelling) or DEM (Digital Elevation Modelling).
• Natural and man-made features such as transportation networks, settlements, and administrative boundaries are represented spatially in GIS (Geographical Information System) using geo-referenced data and integrated with attribute or non-spatial information.
• For planning, evaluation, and monitoring, as well as civilian and military reconnaissance and land use planning, baseline, thematic, and 2D and 3D topographical maps are required.

Advantages of Remote Sensing Satellites

• The advantages of satellite-based remote sensing over other techniques include its broad coverage, time savings, and tremendous cost effectiveness.
• Large area coverage allows for a regional survey of a wide range of themes and the identification of large features.
• Coverage that is repeated, allowing monitoring of dynamic themes such as water, agriculture, and so on.
• Data collection at various heights.
• Data collection in inaccessible areas.

Conclusion

Since the launch of IRS-1A in 1988, India's remote sensing satellite fleet has come a long way. These satellites, which have advanced sensors and capabilities, are used for a variety of applications such as disaster management, agriculture, forestry, and infrastructure planning. India's remote sensing satellites provide numerous benefits to the country and the world, and they demonstrate India's progress in space technology.

FAQs

MCQs

1. What does remote sensing primarily rely on?

A) Direct contact with the object
B) Acquiring information from a distance
C) Manual observation
D) Ground surveys

2. Which of the following is an application of remote sensing?

A) Predicting earthquakes
B) Mapping land use and cover
C) Calculating population density
D) Monitoring traffic congestion

3. Which type of sensor emits its energy?

A) Passive sensor
B) Active sensor
C) Thermal sensor
D) Multispectral sensor

4. Which Indian satellite system is known for its remote sensing capabilities?

A) GSAT
B) IRS
C) INSAT
D) NavIC

5. What is a challenge faced in remote sensing?

A) Limited satellite access
B) Atmospheric interference
C) High costs of sensors
D) Lack of data

GS Mains Questions and Model Answers

Q1: Discuss the significance of remote sensing in environmental monitoring and management.

Answer: Remote sensing plays a crucial role in environmental monitoring and management by providing comprehensive data on land use changes, deforestation, water resources, and climate change impacts. It enables scientists and policymakers to visualize and analyze vast areas quickly and accurately, facilitating informed decision-making. For example, remote sensing data can help assess the extent of damage caused by natural disasters, monitor air and water quality, and manage natural resources sustainably. This technology aids in tracking changes over time, allowing for proactive management strategies to address environmental challenges.

Q2: Analyze the role of Indian Remote Sensing (IRS) systems in agricultural monitoring.

Answer: The Indian Remote Sensing (IRS) systems play a vital role in agricultural monitoring by providing timely and accurate information on crop health, soil conditions, and land use patterns. Through high-resolution satellite imagery, farmers can receive insights into crop conditions, enabling them to make informed decisions regarding irrigation, pest management, and fertilizer application. IRS data supports the government in formulating policies related to food security and agricultural sustainability, helping to improve yields and optimize resource use in the agricultural sector.

Q3: Evaluate the challenges and limitations of using remote sensing technology in urban planning.

Answer: While remote sensing technology offers significant benefits for urban planning, it also presents challenges and limitations. One major challenge is the variability in data accuracy due to atmospheric conditions, which can affect the interpretation of imagery. Additionally, integrating remote sensing data with existing urban infrastructure and socio-economic data can be complex, requiring specialized skills and tools. Furthermore, high-resolution satellite images may be costly and limited in availability for rapid urban development areas. Addressing these challenges necessitates collaboration between urban planners, geospatial analysts, and policymakers to ensure effective use of remote sensing in urban environments.

Previous Year Questions on Remote Sensing

1. UPSC CSE Prelims 2019:

Question: What is the main advantage of using remote sensing in land use planning?

A) Cost-effectiveness
B) Real-time monitoring
C) Accessibility of data
D) None of the above

Answer: (B)

Explanation: The main advantage of using remote sensing in land use planning is real-time monitoring, allowing for timely data on land changes.

2. UPSC CSE Mains 2020 (GS Paper 3):

Question: "Assess the impact of remote sensing technology on resource management in India." Discuss with examples.

Answer: Remote sensing technology has significantly impacted resource management in India by providing critical data for managing natural resources effectively. For instance, it is used to monitor forest cover changes, assess water bodies, and manage agricultural resources through crop monitoring. Remote sensing aids in disaster management by providing timely information on flood-prone areas, enabling better preparedness and response strategies. This technology facilitates sustainable resource management by allowing for informed decision-making and policy formulation to address environmental challenges in the country.