With reference to the Indian Regional Navigation Satellite System (IRNSS), consider the following statements: 1. IRNSS has three satellites in geostationary and four satellites in geosynchronous orbits. 2. IRNSS covers entire India and about 5500 sq. km beyond its borders. 3. India will have its own satellite navigation system with full global coverage by the middle of 2019. Which of the statements given above is/are correct?
Contents12
- A1 only
- B1 and 2 only
- C2 and 3 only
- DNone
Show answer
Answer: (A) 1 only
Correct Answer: (a) 1 only
Statement 1 is CORRECT: IRNSS (Indian Regional Navigation Satellite System), also called NavIC, consists of 7 satellites. Of these, 3 are in geostationary orbit (GEO — they stay fixed over one point above the equator) and 4 are in geosynchronous orbit (GSO — they follow a figure-8 path over the equator).
Statement 2 is WRONG: IRNSS covers India and a region extending 1,500 km around it — it does NOT cover the entire world. It is a REGIONAL system, not global. That's why it's called 'Indian Regional Navigation Satellite System.' For comparison, GPS (American) and GLONASS (Russian) are global systems.
Statement 3 is WRONG: India does use its own satellite system for navigation. GAGAN (GPS Aided Geo Augmented Navigation) is India's space-based augmentation system that improves the accuracy of GPS signals over India. It was developed jointly by ISRO and AAI (Airports Authority of India). India is NOT fully dependent on only American GPS.
REMEMBER:
NavIC/IRNSS = 7 satellites (3 GEO + 4 GSO).
Regional coverage only (India + 1,500 km).
India also has GAGAN to improve GPS accuracy.
NavIC is India's own navigation system — not dependent solely on American GPS.
IRNSS (NavIC) is India's own satellite navigation system with 7 satellites - 3 in geostationary and 4 in geosynchronous orbits, providing regional coverage over India and 1,500 km beyond.
India launched IRNSS to reduce dependence on foreign satellite navigation systems like GPS, especially after the US denied GPS access during the 1999 Kargil War.
The question tests whether students understand the difference between regional systems like IRNSS and global systems like GPS, and can distinguish between different satellite orbit types.
IRNSS (NavIC) Satellite System
Science And Technology IRNSS NavIC Indian Regional Navigation Satellite System
IRNSS (NavIC): India's Regional Navigation System
IRNSS/NavIC has 7 satellites: 3 in geostationary + 4 in geosynchronous orbits
Coverage: India + 1,500 km around it (regional, not global)
NavIC = Navigation with Indian Constellation (official name for IRNSS)
Operational since 2018 with positioning accuracy better than 10 meters
IRNSS (Indian Regional Navigation Satellite System) is India's own satellite-based positioning system, officially named NavIC. Unlike global systems like GPS, it provides navigation services only over India and surrounding regions.
IRNSS Satellite Configuration
Orbit Type | Number of Satellites | Orbital Characteristics | Coverage Role |
|---|---|---|---|
Geostationary (GEO) | 3 satellites | Fixed position over equator | Continuous coverage over Indian Ocean region |
Geosynchronous (GSO) | 4 satellites | Figure-8 path over equator | Extended coverage for northern regions |
Key Technical Features
Dual frequency signals (L5 and S bands) for better accuracy
Positioning accuracy: Better than 10 meters over service area
Service area: India and region extending 1,500 km from borders
Applications: Transportation, mapping, disaster management, vehicle tracking
Ground segment: Network of ranging stations across India
Trap: IRNSS covers 1,500 km around India, not 5,500 km as in Statement 2
Trap: IRNSS is regional, not global - it cannot provide worldwide coverage
Trap: Don't confuse geostationary (3 satellites, fixed position) with geosynchronous (4 satellites, figure-8 path)
Global Navigation Satellite Systems
Science And Technology GPS GLONASS
Global vs Regional Navigation Systems: Comparison
GPS (USA), GLONASS (Russia), Galileo (EU), BeiDou (China) are global systems
IRNSS/NavIC (India) and QZSS (Japan) are regional systems
Global systems need 24-32 satellites vs regional systems need 7-10 satellites
Major Navigation Systems
System | Country | Coverage | Satellites | Status |
|---|---|---|---|---|
GPS | USA | Global | 31 satellites | Fully operational since 1995 |
GLONASS | Russia | Global | 24 satellites | Fully operational |
Galileo | European Union | Global | 30 satellites | Operational since 2016 |
BeiDou | China | Global | 35 satellites | Global coverage since 2020 |
IRNSS/NavIC | India | Regional | 7 satellites | Operational since 2018 |
QZSS | Japan | Regional | 7 satellites | Covers Asia-Pacific |
Why Regional Systems Matter
Strategic independence: Reduces dependence on foreign navigation systems
Military applications: Ensures navigation services during conflicts
Higher accuracy: Optimized for specific geographic regions
Cost effective: Fewer satellites needed compared to global systems
GAGAN Satellite System
Science And Technology GAGAN
GAGAN: India's GPS Augmentation System
GAGAN = GPS Aided Geo Augmented Navigation system
Joint project of ISRO and AAI (Airports Authority of India)
Improves GPS accuracy over Indian airspace for civil aviation
GAGAN enhances GPS signals over India to provide better accuracy for civilian aircraft navigation. It uses geostationary satellites to send correction signals that improve GPS accuracy from meters to 3 meters or better.
GAGAN Key Features
Primary use: Civil aviation approach and landing guidance
Coverage: Indian Flight Information Region (FIR)
Accuracy: Improves GPS accuracy to 3 meters or better
Satellites used: GSAT-8 and GSAT-10 for signal broadcasting
International standard: Compliant with ICAO (International Civil Aviation Organization)
India's Navigation Systems
System | Purpose | Technology | Accuracy | Users |
|---|---|---|---|---|
GAGAN | GPS enhancement | Augments US GPS signals | 3 meters | Civil aviation primarily |
NavIC/IRNSS | Independent navigation | Indian satellites only | 10 meters | All civilian & military users |
Geostationary vs Geosynchronous Orbits
Science And Technology geostationary geosynchronous
Satellite Orbits: Geostationary vs Geosynchronous
Geostationary: Satellite appears fixed over one point on Earth
Geosynchronous: Satellite has 24-hour period but moves in figure-8 pattern
Both orbits are at 35,786 km altitude above Earth
Orbit Types Comparison
Orbit Type | Altitude | Orbital Period | Ground Track | Applications |
|---|---|---|---|---|
Geostationary (GEO) | 35,786 km | 24 hours | Fixed point over equator | Communication, weather satellites |
Geosynchronous (GSO) | 35,786 km | 24 hours | Figure-8 pattern over equator | Navigation, regional coverage |
Low Earth Orbit (LEO) | 160-2000 km | 90-120 minutes | Passes over entire Earth | Earth observation, ISS |
Why IRNSS Uses Both Orbits
3 GEO satellites: Provide continuous coverage over Indian Ocean region
4 GSO satellites: Better coverage for northern regions of India
Combined advantage: Ensures at least 4 satellites visible from any point in service area
Redundancy: If one satellite fails, system continues to work
Trap: All geostationary orbits are geosynchronous, but not all geosynchronous orbits are geostationary
Trap: Geostationary = fixed position; Geosynchronous = same period but can move in patterns
Trap: Both types are at the same altitude (35,786 km) - don't confuse altitude with behavior