Question

The basic premise for using the DGPS technique is to reduce the errors due to

• A. atmosphere, satellite orbit, multipath
• B. atmosphere, satellite orbit, satellite clock
• C. atmosphere, satellite clock, receiver clock
• D. atmosphere, satellite orbit, satellite clock, receiver clock, multipath

Hint:

Remember DGPS removes {common} errors: ionosphere/troposphere, satellite clock, and ephemeris. It cannot fix receiver-unique errors (multipath, receiver clock jitter) without more advanced techniques.

Answer 1

The Correct Option is B

Differential GPS (DGPS) uses a reference receiver at a known location to estimate range errors for each satellite and broadcast corrections to nearby rovers. Because the base and rover are close, several errors are common-mode and hence removable:
\(\bullet\) Atmospheric delays (ionosphere and troposphere) — largely similar over short baselines.
\(\bullet\) Satellite clock drift — common to all receivers for a given satellite.
\(\bullet\) Orbital (ephemeris) error — same broadcast for both receivers.
Errors that are receiver-specific, such as receiver clock and multipath, do not cancel reliably with simple DGPS. Therefore the best match is option (B).
\[ \boxed{\text{(B)}} \]