UPSC Prelims Practice Questions — Why is the NVS-03 satellite launch significant?

Q1. Consider the following statements: Which of the following is correct in respect of the above statements?

  1. Before NVS-03 was launched, when only three NavIC satellites were providing navigation services, a receiver relying on NavIC alone could not work out its position.
  2. A satellite navigation receiver uses signal travel times, and it must solve for its own clock error in addition to its three position coordinates.
  • 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

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

  1. NavIC cannot serve as a standalone positioning system for a user located in South America.
  2. NavIC satellites are placed in low Earth orbit, so the footprint of each satellite covers only a small part of the Earth's surface.
  • 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. Consider the following assertion: 'Several first-generation NavIC satellites stopped being useful for navigation after their onboard atomic clocks failed, even though the satellites themselves remained in orbit.' Which of the statements given above support/supports the assertion?

  1. A receiver works out its distance to a satellite from the time the signal takes to arrive, so any error in the satellite's time reference becomes a direct error in that distance.
  2. Navigation signals travel at the speed of light, so even a timing error of a millionth of a second corresponds to a distance error of hundreds of metres.
  3. The onboard atomic clock is what keeps a navigation satellite in its assigned geosynchronous slot.
  • A. 1, 2 and 3
  • B. 1 only
  • C. 2 and 3 only
  • D. 1 and 2 only

Q4. With reference to the orbits used by regional navigation satellites such as those of NavIC, consider the following statements: Which of the statements given above is/are correct?

  1. A satellite in an inclined geosynchronous orbit drifts steadily eastward around the globe, passing over every longitude once a week.
  2. A geostationary orbit is a special case of a geosynchronous orbit: it is circular and lies in the plane of the equator.
  3. A satellite in an inclined geosynchronous orbit appears to trace a figure-of-eight pattern centred on a fixed longitude.
  • A. 1, 2 and 3
  • B. 1 and 2 only
  • C. 2 and 3 only
  • D. 3 only

Q5. GSLV-F18 injected NVS-03 into an elliptical orbit of about 170.3 km × 38,080 km. The satellite then began firing its own onboard engine. Which one of the following best describes the purpose of these firings?

  • A. To lower the perigee into the upper atmosphere, so that atmospheric drag removes the orbit's excess eccentricity
  • B. To raise the perigee from about 170 km towards 36,000 km, making the orbit nearly circular at geosynchronous height
  • C. To lower both perigee and apogee to about 20,000 km, placing the satellite in a medium Earth orbit like GPS
  • D. To lower the apogee from about 38,000 km towards 170 km, making the orbit nearly circular at low Earth height

Q6. Consider the following facts: GAGAN broadcasts correction and integrity data for GPS signals to serve civil aviation over the Indian region. NavIC is an independent constellation that sends its own ranging signals. Until NVS-03 was launched, only three NavIC satellites were providing positioning services. Which of the following inferences can validly be drawn from the above?

  1. While only three NavIC satellites were working, an aircraft over India using GPS with GAGAN could still have used augmented satellite navigation.
  2. The shortfall in working NavIC satellites reduced the accuracy of the corrections that GAGAN provides to GPS users.
  3. Once NavIC is restored to four working satellites, GAGAN will no longer be needed for civil aviation in India.
  • A. 1 only
  • B. 1 and 3 only
  • C. 1 and 2 only
  • D. 2 and 3 only