India’S Remote Sensing and Cartographic Satellite Programmes

India maintains one of the largest civilian remote sensing satellite constellations in the world, managed by the Indian Space Research Organisation (ISRO). The Indian Remote Sensing (IRS) satellite system was initiated to facilitate sustainable natural resource management, cartographic mapping, oceanographic observation, and disaster management. Beginning with experimental satellites in the late 1970s, India’s Earth Observation (EO) capabilities have evolved into operational constellations that provide sub-metre spatial resolution imagery, synthetic aperture radar (SAR) all-weather monitoring, and hyperspectral data.

Historical Evolution of Indian Remote Sensing

The foundation of Indian remote sensing began with experimental missions designed to test sensor technology and ground application systems.

Bhaskara-I and Bhaskara-II (1979–1981)

• Served as India’s first experimental remote sensing satellites launched by Soviet intercosmos rockets.
• Carried TV cameras and Microwave Radiometers (SAMIR) to collect preliminary data on hydrology, forestry, and oceanography.

IRS-1A and IRS-1B (1988–1991)

• Marked the beginning of India’s operational remote sensing era.
• Equipped with Linear Imaging Self-Scanning Sensors (LISS-I and LISS-II) operating in visible and near-infrared spectral bands.
• Placed in Polar Sun-Synchronous Orbits (SSO) to gather systematic land-use and crop assessment data.

IRS-1C and IRS-1D (1995–1997)

• Introduced high-resolution Panchromatic (PAN) cameras providing spatial resolution under 6 metres, making them leading commercial civilian imaging satellites of their time.
• Carried Wide Field Sensors (WiFS) for regional vegetation mapping and LISS-III sensors for urban planning.

Specialized Remote Sensing Satellite Series

India transitioned from broad thematic imaging to domain-specific constellations targeting land resources, oceanography, atmosphere, and high-resolution mapping.

Resourcesat Series (Land & Agriculture)

• Resourcesat-1 (IRS-P6): Launched in 2003, carried LISS-IV (5.8m resolution), LISS-III, and AWiFS sensors for crop yield estimation, drought monitoring, and land-use mapping.
• Resourcesat-2 & 2A: Placed in orbit in 2011 and 2016 respectively, ensuring multi-spectral data continuity for agricultural and forestry applications.

Oceansat Series (Oceanography & Coastal Zones)

• Oceansat-1 (IRS-P4): Launched in 1999, equipped with Ocean Colour Monitor (OCM) and Multi-frequency Scanning Microwave Radiometer (MSMR) to map potential fishing zones (PFZ).
• Oceansat-2 & EOS-06 (Oceansat-3): EOS-06 was launched in 2022 aboard PSLV-C54, carrying OCM-3, Sea Surface Temperature Monitor (SSTM), and a Ku-band Scatterometer for coastal zone management and cyclone tracking.

Radar Imaging Satellites (RISAT Series – All-Weather Monitoring)

• RISAT-2 (2009): Carried an X-band Synthetic Aperture Radar (SAR) purchased to provide day-and-night, all-weather imaging capabilities, particularly for military intelligence and flood monitoring.
• RISAT-1 & RISAT-1A (EOS-04): Equipped with indigenous C-band SAR sensors. EOS-04 was launched in February 2022 to support agriculture, forestry, soil moisture estimation, and disaster assessment.

Climate and Meteorological Satellites

• Megha-Tropiques (2011): Joint ISRO-CNES (France) mission to study the water cycle and energy exchanges in the tropical atmosphere.
• SARAL (2013): Joint mission carrying AltiKa (Ka-band altimeter) for ocean surface height measurements.
• INSAT-3DR & INSAT-3DS: Geostationary meteorological satellites launched to monitor atmospheric profiles, storm tracking, and search-and-rescue operations.

Cartosat Programme: High-Resolution Mapping

The Cartosat series represents India’s dedicated cartographic satellite programme aimed at large-scale topographic mapping, town planning, infrastructure development, and defense surveillance.

Cartosat-1 (2005)

• First Indian satellite capable of providing in-orbit stereo images using two Panchromatic cameras tilted fore and aft.
• Generated high-precision Digital Elevation Models (DEM) for terrain mapping and cartography.

Cartosat-2 Series (2007–2018)

• Advanced capabilities down to sub-metre spatial resolutions (up to 0.6 metres).
• Included dedicated military reconnaissance variants like Cartosat-2A and Cartosat-2B operated by national security agencies.
• Enabled scene-specific agile steering for spot-feature imaging.

Cartosat-3 (2019)

• Represents a third-generation agile satellite with high-resolution imaging capabilities.
• Achieved a Panchromatic spatial resolution of 0.25 metres—among the highest spatial resolutions in civilian remote sensing globally.
• Features a 1-metre Multispectral resolution and 16 km swath width to assist cadastral mapping and urban infrastructure expansion.

Modern Naming Convention: The EOS Framework

ISRO restructured its Earth Observation portfolio under a unified Earth Observation Satellite (EOS) nomenclature to streamline thematic monitoring.

Ground Segment Infrastructure and Data Utilization

National Remote Sensing Centre (NRSC)

• Located at Shadnagar near Hyderabad, NRSC serves as the primary ground station for acquiring, processing, and distributing Earth observation data.
• Manages the Bhuvan Geoportal, an open-access platform providing satellite imagery, multi-sectoral GIS maps, and public utility planning services.

Space Applications Centre (SAC)

• Located in Ahmedabad, SAC acts as the lead institute for designing and developing optical, microwave, and hyperspectral payloads.

Indian Institute of Remote Sensing (IIRS)

• Located in Dehradun, IIRS delivers professional training and capacity building in remote sensing, GIS, and geo-computation techniques.

Major Applications of Remote Sensing in India

• Agriculture & Crop Assessment: Forecasting production of major crops via programs like FASAL (Forecasting Agricultural output using Space, Agro-meteorology and Land-based observations).
• Water Resources: Mapping surface water bodies, monitoring snowmelt runoff in the Himalayas, and guiding the Rajiv Gandhi National Drinking Water Mission.
• Disaster Management Support (DMS): Providing near-real-time flood mapping, landslide susceptibility zonation, cyclone track predictions, and forest fire alerts.
• Forestry & Biodiversity: Assisting the Forest Survey of India (FSI) in preparing biennial State of Forest Reports (ISFR).
• Coastal and Marine Resources: Generating daily Potential Fishing Zone (PFZ) advisories for coastal fisherfolk via INCOIS.

Key Exam-Oriented Facts and Trivia

• IRS-1A was India’s first operational remote sensing satellite, launched on March 17, 1988, from the Baikonur Cosmodrome.
• Bhuvan is India’s indigenous geospatial platform developed by NRSC, providing 3D spatial visualisations and regional thematic datasets.
• Cartosat-3 features a spatial resolution of 0.25 metres, putting it among the top civilian imaging systems globally.
• NISAR (NASA-ISRO Synthetic Aperture Radar) is a joint mission utilizing dual-frequency L-band (NASA) and S-band (ISRO) SAR to measure Earth’s surface changes down to fractions of an inch.
• AgriSTACK and the national digital agriculture ecosystem rely directly on high-resolution spatial inputs supplied by the Cartosat and Resourcesat constellations.
• The Scatterometer onboard EOS-06 provides ocean surface wind vectors used by the India Meteorological Department (IMD) for cyclone intensity forecasting.