UPSC Prelims 2025 · GS Paper I
Question 94: Science and 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?
- IIt is designed to provide additional accuracy and integrity.
- IIIt will allow more uniform and high quality air traffic management.
- IIIIt will provide benefits only in aviation but not in other modes of transportation.
Select the correct answer using the code given below.
AnswerThe answer is (d).
GAGAN, developed by ISRO and the Airports Authority of India, is a satellite-based augmentation system. Ground reference stations measure errors in GPS signals and a master control centre sends corrections through a geostationary satellite, improving accuracy and integrity, so Statement I is correct. It supports more uniform, higher quality air traffic management and precision approaches, so Statement II is correct. Its benefits are not limited to aviation; it can also help in railways, maritime transport, surveying and agriculture, so Statement III is wrong.
- I. GAGAN gives additional accuracy and integrity to GPS signals.
- II. It supports uniform, high quality air traffic management.
- III. It also benefits other modes and uses such as railways, maritime and agriculture.
How you could have got this
- If you were sure statement III is not correct, (a) and (b) go: each of them includes III.
What you needed to know: It also benefits other modes and uses such as railways, maritime and agriculture.
The red flag in statement III is “only”. In UPSC’s papers, statements with “only” were true 27% of the time (82 statements). A hint, not a rule.
- Then, if you were sure statement II is correct, (c) goes: it leaves II out.
What you needed to know: It supports uniform, high quality air traffic management.
Only (d) is left. You didn’t need statement 1.
This follows an unofficial answer: UPSC has not published its key for this year, and if that answer is wrong, so is this path.
Which options go is worked out from UPSC’s key and the options, not by a model.
Why each option is right or wrong
- (a) Wrong: III says benefits are only for aviation, which is incorrect.
- (b) Wrong: III is incorrect.
- (c) Wrong: II about air traffic management is also correct.
- (d) Right: I and II are correct and III wrongly restricts the benefits to aviation.
Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2025, General Studies Paper I, Series A. The paper on upsc.gov.in.