UPSC Prelims Practice Questions — GSLV places next-generation navigation satellite into orbit

Q1. With reference to India's satellite-based navigation systems, consider the following statements: Which of the statements given above is/are correct?

  1. GAGAN can give an aircraft a position fix even when no GPS satellite is in view of its receiver.
  2. A receiver using NavIC alone can determine its position without any GPS satellite in view.
  3. GAGAN's main purpose is to improve the accuracy and integrity of GPS signals for civil aviation, including approach and landing.
  • A. 1, 2 and 3
  • B. 1 and 2 only
  • C. 2 and 3 only
  • D. 2 only

Q2. Suppose a launch vehicle correctly injects a navigation satellite into a geosynchronous transfer orbit, but the satellite's own orbit-raising engine then fails to fire. Which one of the following best describes what follows?

  • A. It escapes Earth's gravity, as its speed at the high point of the transfer orbit is greater than the escape velocity.
  • B. It falls back to Earth within a few hours, as the low point of a transfer orbit lies inside the dense lower atmosphere.
  • C. It slowly settles into a circular geostationary orbit, as air drag at the low point of each revolution gradually lifts it.
  • D. It keeps circling in an elongated orbit, its altitude swinging between near-Earth and geostationary heights each revolution.

Q3. With reference to orbits used by navigation and communication satellites, consider the following statements: Which of the statements given above is/are correct?

  1. Every geostationary orbit is a geosynchronous orbit, but not every geosynchronous orbit is geostationary.
  2. A satellite in an inclined geosynchronous orbit appears from the ground to swing north and south of the equator, tracing a figure-of-eight ground track.
  3. A satellite in a geosynchronous transfer orbit completes one revolution in about 24 hours, since the high point of its orbit lies at geostationary altitude.
  • A. 1, 2 and 3
  • B. 1 and 2 only
  • C. 1 only
  • D. 2 and 3 only

Q4. With reference to the cryogenic upper stage used on the GSLV, consider the following statements: Which of the statements given above is/are correct?

  1. It burns liquid hydrogen with liquid oxygen, both of which must be kept at temperatures far below 0 °C to remain liquid.
  2. Cryogenic propellants are favoured for upper stages mainly because they can be kept loaded in the vehicle for long periods without loss.
  3. Because liquid hydrogen has a very low density, the stage needs large, heavily insulated tanks relative to the mass of propellant it carries.
  • A. 1 and 3 only
  • B. 1 and 2 only
  • C. 3 only
  • D. 1, 2 and 3

Q5. With reference to the role of timing in satellite navigation systems such as NavIC, consider the following statements: Which of the statements given above is/are correct?

  1. An error of one microsecond in a satellite's clock would shift the measured range by roughly 300 metres, because the signal travels at the speed of light.
  2. A receiver needs signals from at least four satellites, since besides three position coordinates it must also solve for the offset of its own inexpensive clock.
  3. Precise time broadcast by navigation satellites can be used to synchronise telecom networks and power grids even where location is not needed.
  • A. 1, 2 and 3
  • B. 2 and 3 only
  • C. 1 and 3 only
  • D. 1 and 2 only

Q6. Consider the following statements: Which of the following is correct in respect of the above statements?

  1. A navigation satellite whose onboard atomic clocks have failed can no longer contribute to positioning, even though it remains healthy in its orbit.
  2. A navigation receiver computes its distance from each satellite using the precisely timed signals that the satellite broadcasts.
  • 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

Q7. With reference to the addition of the L1 signal to NavIC satellites from the NVS series onwards, consider the following statements: Which of the statements given above is/are correct?

  1. It makes NavIC easier to use on mass-market devices, whose chipsets are built around the band already used by other navigation systems.
  2. A single receiver can more readily combine NavIC satellites with those of other constellations, which helps where buildings or terrain block part of the sky.
  3. It extends NavIC's primary service area from a regional footprint to near-global coverage.
  • A. 1, 2 and 3
  • B. 1 only
  • C. 1 and 2 only
  • D. 2 and 3 only

Q8. Consider the following statements: Which of the following is correct in respect of the above statements?

  1. NavIC satellites of the NVS series broadcast navigation signals in the L1 band in addition to the L5 and S bands.
  2. A single-frequency L1 signal removes ionospheric delay on its own, which a combination of two signal frequencies cannot do.
  • 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