UPSC Prelims 2025Question 94Science & Technology

GPS-Aided Geo Augmented Navigation (GAGAN) uses a system of ground stations to provide necessary augmentation. Which of the following statements is/are correct in respect of GAGAN?
I. It is designed to provide additional accuracy and integrity.
II. It will allow more uniform and high quality air traffic management.
III. It will provide benefits only in aviation but not in other modes of transportation.
Select the correct answer using the code given below.

Options

(a)I, II and III
(b)II and III only
(c)I only
(d)I and II only

Correct answer: d

Decision rule

A statement that a technology benefits only one sector is almost always false; systems built for aviation also serve maritime, road, rail and agriculture.

Explanation

Correct Answer:

(d) I and II only

Explanation of the Correct Answer

Let's analyze the statements related to GPS-Aided Geo Augmented Navigation (GAGAN):

Statement-wise Analysis

I. It is designed to provide additional accuracy and integrity.

Correct
GAGAN is a Satellite-Based Augmentation System (SBAS) developed by India to enhance the accuracy, integrity, and availability of GPS signals.
It improves positioning accuracy to meet the stringent requirements of civil aviation.

II. It will allow more uniform and high quality air traffic management.

Correct
GAGAN enhances air navigation safety and efficiency, enabling better air traffic management across the Indian airspace and adjoining regions.
It supports more precise flight operations, including approaches and landings.

III. It will provide benefits only in aviation but not in other modes of transportation.

Incorrect
Although primarily designed for aviation, GAGAN's accurate and reliable positioning can benefit other sectors as well, including maritime, road, and rail transportation, agriculture, and disaster management.

Why Other Options Are Incorrect

(a) I, II and III – Incorrect: Statement III is incorrect.
(b) II and III only – Incorrect: Statement I is correct; Statement III is incorrect.
(c) I only – Incorrect: Statement II is also correct.
(d) I and II only – Correct

Relevant Supplementary Information

Aspect	Details
GAGAN	India's Satellite-Based Augmentation System (SBAS) improving GPS accuracy and integrity for aviation.
Accuracy and Integrity	Ensures signal reliability and precise navigation critical for flight safety.
Air Traffic Management	Enables uniform and high-quality airspace utilization and management.
Other Applications	Benefits other sectors requiring precise navigation like maritime, road transport, agriculture.

Related Concepts or Facts

Concept	Explanation
Satellite-Based Augmentation System (SBAS)	Enhances GNSS signals for better accuracy, integrity, and availability.
GPS (Global Positioning System)	Global navigation satellite system providing location data worldwide.
Navigation Accuracy	Crucial for aviation safety, allowing precise landing and routing.

Current Relevance

GAGAN is part of India's efforts to modernize its air traffic infrastructure and support safe, efficient air navigation.
Its applications beyond aviation are growing with advancements in location-based services.

Table: Related Concepts and Terms – GAGAN and Satellite-Based Augmentation Systems

Concept / Term	Explanation / Relevance
GAGAN (GPS-Aided Geo Augmented Navigation)	India's Satellite-Based Augmentation System (SBAS) designed to enhance GPS accuracy, integrity, and availability, primarily for civil aviation.
Satellite-Based Augmentation System (SBAS)	Technology that improves the accuracy and reliability of GNSS signals by providing correction data from ground stations via satellites.
GPS (Global Positioning System)	A global satellite navigation system providing positioning, navigation, and timing services worldwide.
Accuracy	The degree of closeness of the measured position to the true position; GAGAN improves this for aviation safety.
Integrity	Assurance that the navigation system is providing timely warnings when the system should not be used for navigation.
Air Traffic Management (ATM)	Systems and procedures that ensure safe and efficient movement of aircraft in airspace and airports.
Applications Beyond Aviation	GAGAN’s improved navigation services also benefit maritime, road transport, agriculture, and disaster management.
Ground Stations	Facilities that monitor GNSS signals and send correction data to satellites for augmentation.
Regional Navigation Satellite System (RNSS)	Satellite systems like GAGAN that serve specific regions, augmenting global GNSS like GPS and Galileo.

Table: Global Satellite-Based Augmentation Systems (SBAS)

SBAS Name	Region Covered	Managing Organization	Key Features
GAGAN	India and adjoining regions	Airports Authority of India (AAI) / ISRO	Improves GPS accuracy and integrity for civil aviation; supports other sectors.
WAAS (Wide Area Augmentation System)	United States and parts of Canada, Mexico	Federal Aviation Administration (FAA), USA	First operational SBAS; provides aviation navigation support over North America.
EGNOS (European Geostationary Navigation Overlay Service)	Europe	European Space Agency (ESA) and European Commission	Enhances GPS and Galileo signals for aviation and other sectors in Europe.
MSAS (Multi-functional Satellite Augmentation System)	Japan and surrounding Asia-Pacific	Japan Civil Aviation Bureau (JCAB)	Provides navigation augmentation primarily for civil aviation in Japan.
SNAS (Satellite-based Navigation Augmentation System)	China (planned/under development)	China National Space Administration (CNSA)	Intended to augment BeiDou system for improved navigation accuracy.
SDCM (System for Differential Corrections and Monitoring)	Russia	Russian Federal Space Agency (Roscosmos)	Augments GLONASS signals for enhanced navigation in Russia.

Additional Notes:

These SBAS systems augment GNSS signals by providing correction and integrity information to improve accuracy and reliability.
They are primarily designed for aviation safety but also benefit maritime, agriculture, and land transport sectors.
The systems use ground monitoring stations and geostationary satellites to broadcast corrections.

Explanation of NAVIC and IRNSS

IRNSS (Indian Regional Navigation Satellite System) is the original name of India’s regional satellite navigation system.
It was later renamed NAVIC (Navigation with Indian Constellation).
NAVIC/IRNSS is an independent regional satellite navigation system, similar to GPS, GLONASS, Galileo, and BeiDou, providing accurate positioning information over India and surrounding region (about 1,500 km radius).
Unlike GAGAN, which is an augmentation system that enhances the GPS signal, NAVIC provides standalone positioning and timing services.

Difference Between NAVIC/IRNSS and GAGAN

Aspect	NAVIC/IRNSS	GAGAN
Type of System	Regional Satellite Navigation System (RNSS)	Satellite-Based Augmentation System (SBAS)
Functionality	Provides independent satellite-based navigation and positioning	Enhances GPS signals for better accuracy and integrity
Coverage	India and about 1,500 km around	India and adjoining regions
Number of Satellites	7 satellites in geosynchronous and geostationary orbits	Uses geostationary satellites to broadcast corrections
Primary Use	Navigation, timing, location-based services	Aviation safety, enhanced navigation accuracy
Operational Since	Fully operational since 2018	Operational since 2013

Additional Notes

NAVIC/IRNSS can operate independently without GPS, useful in GPS-denied environments.
GAGAN improves the GPS signal's reliability and accuracy over Indian airspace, benefiting aviation and other sectors.
Both systems complement each other for enhancing India’s satellite navigation capabilities.

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