UPSC Prelims Practice Questions — Slow recovery

Q1. With reference to how a satellite navigation receiver determines its position, consider the following statements: Which of the statements given above is/are correct?

  1. A receiver needs signals from at least four satellites because, besides its three position coordinates, it must also solve for the offset between its own clock and satellite time.
  2. A satellite that remains in its designated orbit but whose onboard atomic clocks have all failed still provides a usable ranging signal for computing position.
  3. If a receiver's clock were perfectly synchronised with satellite time, signals from three satellites would in principle be enough to compute its position.
  • A. 1 and 2 only
  • B. 2 and 3 only
  • C. 1, 2 and 3
  • D. 1 and 3 only

Q2. Consider the following statements: Which of the following is correct in respect of the above statements?

  1. For several months in 2026, NavIC could not provide standalone positioning over the Indian region even though more than four of its satellites were still in orbit.
  2. A navigation satellite contributes to position-fixing only while it has a working atomic clock, because positioning rests on precisely timed ranging signals; a satellite whose clocks have failed may still relay one-way messages.
  • A. Both Statement-I and Statement-II are correct and Statement-II explains Statement-I
  • B. Both Statement-I and Statement-II are correct, but Statement-II does not explain Statement-I
  • C. Statement-I is correct, but Statement-II is incorrect
  • D. Statement-I is incorrect, but Statement-II is correct

Q3. NavIC's first-generation satellites carried imported atomic clocks, several of which failed in orbit. By March 2026 only three NavIC satellites could provide positioning, navigation and timing services, and on 31 October 2026 a newly launched NVS satellite raised the count to four. Which of the following inferences can validly be drawn from the above?

  1. Immediately after the restoration the constellation had no margin: losing the working clocks on any one of the four satellites would again end standalone positioning.
  2. Between March and October 2026, users in the Indian region could not obtain any satellite-based position fix at all.
  3. The in-orbit clock failures show that the imported clocks were less accurate than the indigenous clocks now being flown.
  • A. 2 and 3 only
  • B. 1 only
  • C. 1 and 2 only
  • D. 1, 2 and 3

Q4. With reference to global and regional navigation satellite systems, consider the following statements: Which of the statements given above is/are correct?

  1. NavIC can cover its service area with a constellation of only seven satellites because they are placed in geostationary and inclined geosynchronous orbits, which keep them over a fixed longitude band.
  2. Japan's QZSS is, like NavIC, a regional system, whereas BeiDou, like Galileo, is a global system.
  3. A regional system's signals are usable anywhere on Earth; only its accuracy guarantee is confined to the declared service area.
  • A. 1 and 3 only
  • B. 1, 2 and 3
  • C. 1 and 2 only
  • D. 2 only

Q5. With reference to NavIC and GAGAN, consider the following statements: Which of the statements given above are correct?

  1. GAGAN can generate position fixes for aircraft on its own when GPS signals are unavailable.
  2. GAGAN broadcasts integrity information that warns users when GPS-derived positions should not be trusted, which is needed for safety-of-life aviation use.
  3. NavIC, being a standalone system rather than an augmentation, is designed to support safety-of-life operations such as aircraft landing approaches.
  4. GAGAN is interoperable with other satellite-based augmentation systems such as WAAS and EGNOS.
  • A. 2 and 4 only
  • B. 2, 3 and 4 only
  • C. 1, 3 and 4 only
  • D. 1 and 2 only

Q6. With reference to India's PSLV and GSLV launch vehicles, consider the following statements: Which of the statements given above is/are correct?

  1. GSLV's cryogenic upper stage imparts the high velocity that characterises a geosynchronous transfer orbit, which suits it to carrying satellites bound for geosynchronous slots.
  2. GSLV Mk II's first and second stages are derived from PSLV's, so a failure traced to a shared design element can force checks on both vehicles.
  3. Although PSLV is designed mainly for polar and sun-synchronous low Earth orbits, it has also placed satellites of the IRNSS constellation into orbit.
  • A. 2 and 3 only
  • B. 1 only
  • C. 1 and 2 only
  • D. 1, 2 and 3

Q7. A navigation satellite is launched by GSLV into a geosynchronous transfer orbit and is meant to end up at an operational slot in an inclined geosynchronous orbit. In this context, consider the following statements: Which of the statements given above is/are correct?

  1. Once in its final inclined geosynchronous orbit, the satellite will appear stationary at a fixed point in the sky, just as a geostationary satellite does.
  2. After separating from the launch vehicle, the satellite relies on its own propulsion system to raise its orbit from the transfer orbit to its final slot.
  3. The launch can be fully successful and the satellite still fail to reach its operational slot.
  • A. 2 only
  • B. 2 and 3 only
  • C. 1 and 2 only
  • D. 1, 2 and 3

Q8. With reference to the Departmentally Related Standing Committees (DRSCs) of Parliament, consider the following statements: Which of the statements given above is/are correct?

  1. A DRSC examines the demands for grants of the ministries under its purview, looking at trends in allocation, utilisation levels and policy priorities.
  2. The government must report back on whether it has accepted a DRSC's recommendations, and the committee then tables an Action Taken Report on them.
  3. Once a DRSC's report is laid in Parliament, its recommendations bind the department concerned unless the House votes to reject them.
  • A. 2 and 3 only
  • B. 1, 2 and 3
  • C. 1 and 2 only
  • D. 1 only