Surveying Questions & Answers for Exams on “GPS – Determining Satellite to User Range”.
1. In pseudo ranging, travel time is measured by ___________
a) PRN code
b) Noise code
c) SPS
d) GPS
Answer: a
Clarification: GPS can generate PRN codes that indicate Pseudo Random Noise. It is transmitted along with the signal. While travelling along with the signal, it is capable of determining the travel time of the signal which is correlated with the reference PRN codes for processing.
2. Satellite to user range can be calculated by using which of the following methods?
a) Relative positioning
b) Absolute positioning
c) Carrier wave
d) Pseudo ranging
Answer: d
Clarification: Pseudo ranging is the measure of distance between satellite and the receiver antenna. It can refer the time of emission and reception of codes by which the satellite and user range can be detected and further used in many cases.
3. For obtaining relative time of transmission and reception of signals, it is required to calculate clock offset.
a) False
b) True
Answer: b
Clarification: Clock offset must be placed in the satellite containing GPS so that it can be able to compute the relative time of transmission and reception of radio signal. By knowing this, the satellite to user range can be defined.
4. GPS can also be known as __________
a) GOS
b) Arc GIS
c) GIS
d) NavStar
Answer: d
Clarification: The Global Positioning System can also be determined as NavStar. The main functioning of GPS is to track the location of the specified place or object using the satellites and the receiver.
5. Determine the distance between satellite and user if the time difference can be calculated as 3 min.
a) 54*1019 m
b) 45*102 m
c) 54*109 m
d) 45*109 m
Answer: c
Clarification: The distance between satellite and user can be determined by using the formula,
Distance = speed of light * time difference
Distance = 3*108*(3*60) m
Distance = 54 * 109 m.
6. In order to determine the satellite to user range, which of the following is exceptionally required?
a) Time difference of polarized signals
b) Time difference of signals
c) Time difference of refracted signals
d) Time difference of reflected signals
Answer: b
Clarification: For the determination of the satellite to user range, the time difference between the signal sent and the signal received is compulsory. This can be recorded only if there is a signal. So, for determining range a precise signal is necessary.
7. Almanac contains information about __________
a) Status of the signals
b) Status of the reflection
c) Status of the satellites
d) Status of the aperture
Answer: c
Clarification: The determination of data by GPS involves two procedures almanac and ephemeris. Almanac contains information about the status of the satellites and the approximate orbital information.
8. Trilateration is a plane surveying method.
a) False
b) True
Answer: b
Clarification: Trilateration is the basic principle involved in the GPS surveying. This was originally used in case of basic surveying, where the calculation involves a couple of mathematical operations.
9. Accuracy of the position through can be influenced by ____________
a) Refraction
b) Reflection
c) Signal strength
d) Position of satellite
Answer: d
Clarification: There are certain factors which can affect the accuracy of the position obtained by GPS. Those include the position of satellite, atmospheric conditions, satellite clock errors and ephemeris errors.
10. Error in altitude will be twice the horizontal error.
a) True
b) False
Answer: a
Clarification: The error in the accuracy of GPS can also be caused due to the increase in altitude of the satellite. The error caused due to the horizontal increase in distance is less when compared to altitude error.
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