Surveying Multiple Choice Questions on “GPS – Calculation of User Position”.
1. Which of the following is necessary for further processing in code based positioning?
a) Frequency
b) Carrier wave
c) Receiver clock error
d) Satellite
Answer: c
Clarification: In pseudo ranging, code based positioning takes places, which needs a certain parameter to continue further. Those include receiver clock error and the position of co-ordinates. By using these, equations can be developed for solving the unknowns.
2. Two satellites are enough for finding accurate position of the object.
a) False
b) True
Answer: a
Clarification: GPS is used in finding the location of object. In order to have an accurate location of the object, it is recommended to have at least four satellites in contact of the object to locate the point. Otherwise, it may consume more time for having the output.
3. Carrier phase uses the principle of ____________
a) Compass
b) Theodolite
c) EDM
d) Traversing
Answer: c
Clarification: Carrier phase uses the principle of EDM, where the measurement of phase is done. GPS can measure the difference between the phase of oscillator and receiver satellite. It can attain accuracy up to 3-10 mm.
4. Which of the following can be identified as the correct set for position fixing method?
a) Carrier phase, relative positioning
b) Code phase, absolute positioning
c) Absolute positioning, relative positioning
d) Code phase, carrier phase
Answer: d
Clarification: In GPS, fixing position plays an n important role which must be done with accuracy. So as to attain accuracy, it involves certain methods like code phase and carrier phase.
5. Cycle slip occurs due to change in____________
a) Wave length
b) Phase
c) Frequency
d) Velocity
Answer: b
Clarification: In a carrier phase, the determination of initial ambiguity is foremost important as t has to measure the carrier phase. Ambiguity must be fixed so that the phase can be locked. If at all the phase loses its lock formation of cycle slip occurs.
6. Kinematic positioning will come under which of the following classification?
a) Relative positioning
b) Absolute positioning
c) Resection method
d) Carrier wave method
Answer: a
Clarification: Relative positioning involves certain classifications. Those are given as kinematic positioning, static positioning, stop-and-go GPS positioning. Each one can be adopted based on the type of work being done as all of them yield better results.
7. Base receiver is kept stationary in which of the following operations?
a) Stop-and-go positioning
b) Kinematic positioning
c) Fast static positioning
d) Static positioning
Answer: c
Clarification: Fast static positioning follows the same principle of static positioning. In static positioning, all receivers are kept stationary where as in fast static positioning, only base receiver is kept stationary.
8. If the connection of the number of satellites decreases, the accuracy of the positioning increases.
a) True
b) False
Answer: b
Clarification: The accuracy of the position can be improved only if the numbers of satellites connected to the user are more. In general, a maximum of four satellites must be connected to the user for having a better output.
9. Which of the following indicates the correct set of GPS data classification?
a) Almanac and ephemeris
b) Ephemeris and user segment
c) Ephemeris and space segment
d) Almanac and user segment
Answer: a
Clarification: The GPS data has been classified so as to have a correct idea about the work going on. The classification includes almanac and ephemeris. This data is continuously transmitted by the GPS satellites and the GPS receivers.
10. The GPS time must be very accurate.
a) True
b) False
Answer: a
Clarification: For the calculation of the time that the GPS signal took, we need to have an accurate time of the signal. The GPS satellites possess atomic clocks, which are able to keep the time very precise. Sometimes it is not feasible to set an atomic clock.