Remote sensing

noun (uncountable)

/rɪˈməʊt ˈsɛnsɪŋ/

The acquisition of information about an object, area, or phenomenon without direct physical contact, typically using satellite- or aircraft-borne sensors that detect electromagnetic radiation reflected or emitted from the Earth's surface across visible, infrared, microwave, and other spectral bands. In UPSC context, ISRO's remote sensing programme — through satellites such as Resourcesat-2A (LISS-IV, 5.8 m resolution), Cartosat-3 (0.25 m resolution, defence use), RISAT-2B (synthetic aperture radar for cloud-penetrating imagery), and the NISAR joint NASA-ISRO radar satellite (to be launched 2024–25) — supports crop acreage estimation (FASAL programme), forest cover assessment, disaster monitoring, urban sprawl mapping, and border surveillance. India's National Remote Sensing Centre (NRSC), Hyderabad, under ISRO, is the nodal agency.

✍️ Usage in a UPSC answer

ISRO's RISAT-2B synthetic aperture radar satellite, with its ability to penetrate cloud cover and operate day or night, has substantially enhanced India's remote sensing capability for real-time flood inundation mapping, border infiltration surveillance, and crop-damage assessment in monsoon-affected districts.

Synonyms

Earth observationsatellite imageryaerial sensinggeospatial sensingsatellite-based observation

Antonyms

ground-based sensingin-situ measurementdirect contact measurementproximate sensing

🌱 Word Family

remote sensing (n), sensor (n), remote sensor (n), geospatial (adj, related), NRSC (abbr), SAR (Synthetic Aperture Radar, abbr), multispectral (adj)

🔡 Root

Latin remotus = removed, distant (re- = back + movere = to move); Latin sensus = perception, feeling (from sentire = to feel/perceive)

📜 Etymology

The modern compound remote sensing was coined in 1960 by US geographer Evelyn Pruitt at the US Office of Naval Research to describe the emerging practice of collecting Earth data from aerial and satellite platforms. Remote derives from Latin remotus ('distant'); sensing from Latin sentire ('to feel/perceive').

🧠 Memory Hook

REMOTE (distant) + SENSING (detecting/perceiving): sensing from a distance — like seeing a flood from space without touching the water. NRSC Hyderabad is India's hub. Remember the satellite family: Resourcesat (crops), Cartosat (maps/defence), RISAT (radar through clouds), NISAR (joint with NASA) — each is a remote-sensing tool for a different purpose.

📝 Seen in UPSC Question Papers

Prelims 2015 — Space Technology

Real UPSC previous-year questions whose text uses “Remote sensing” — proof this word earns its place on your list.

🔬 Science & Technology 📖 Seen in: Emerging Technologies — AI, Quantum Co...

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