PS GNSS & RTK Survey Technology 2

Question 1

What is the primary purpose of the ionospheric-free (L3) linear combination in GNSS processing?

Accepted Answer

Eliminate first-order ionospheric delay

Answer

The L3 ionospheric-free combination uses a weighted difference of L1 and L2 measurements to cancel first-order ionospheric delay.

Question 2

In an RTK survey, a 'float' solution indicates that:

Accepted Answer

Ambiguity resolution is incomplete and decimal values remain

Answer

A float solution means the carrier-phase integer ambiguities have not yet been fixed and the solution retains non-integer (decimal) ambiguity estimates.

Question 3

Which GNSS constellation operates primarily in the L1, L2, and L5 frequency bands and is operated by the United States Department of Defense?

Accepted Answer

GPS

Answer

GPS (Global Positioning System) is the U.S. DoD-operated constellation transmitting on L1 (1575.42 MHz), L2 (1227.60 MHz), and L5 (1176.45 MHz).

Question 4

A surveyor notices the RTK baseline length is 45 km. What is the most likely accuracy concern?

Accepted Answer

Tropospheric and ionospheric errors become difficult to model and cancel

Answer

Over long baselines, atmospheric errors (troposphere and ionosphere) do not cancel between rover and base, degrading RTK accuracy significantly.

Question 5

What does PDOP stand for and what does it measure?

Accepted Answer

Positional Dilution of Precision — geometric strength of satellite configuration in 3D

Answer

PDOP (Position Dilution of Precision) quantifies how the geometric arrangement of satellites magnifies ranging errors into position errors in three dimensions.

(PS) Professional Licensed Surveyor Practice Test

(PS) Professional Licensed Surveyor Practice Test

PS GNSS & RTK Survey Technology 2