RPLS Quality Control Procedures 5

Question 1

What does the term 'repeatability' mean in the context of land survey QC?

Accepted Answer

The ability to obtain the same result when the same measurement is made multiple times under the same conditions

Answer

Repeatability measures precision: consistent results across multiple observations under identical conditions indicate low random error and high reliability.

Question 2

A surveyor uses a static GPS observation of 45 minutes and gets an ambiguity resolution ratio of 1.5. This result should prompt the surveyor to:

Accepted Answer

Reject or re-observe the baseline because a ratio below 3.0 indicates a poorly fixed solution

Answer

An ambiguity resolution ratio below 3.0 (some guidelines require > 3.0 to > 5.0) indicates poor confidence in the fixed integer solution, requiring re-observation.

Question 3

Which QC check should be performed after every instrument setup change in a control traverse?

Accepted Answer

Backsight to the previous occupied point and verify the back-azimuth

Answer

After each instrument setup, backsighting the previous point and verifying the back-azimuth confirms that the instrument is correctly oriented before collecting new data.

Question 4

The FGDC Geospatial Positioning Accuracy Standards define accuracy in terms of:

Accepted Answer

The 95% confidence circle radius of horizontal positions relative to the datum

Answer

FGDC standards express horizontal accuracy as the radius of a circle centered at the true position within which 95% of tested points fall, referenced to the national datum.

Question 5

A survey crew discovers that a control monument used for orientation has been disturbed after completing a day's fieldwork. The correct QC response is to:

Accepted Answer

Void the day's data and re-observe from verified control

Answer

Data collected from a disturbed or unreliable control monument must be voided and re-observed from verified control to ensure accuracy and legal defensibility.

(RPLS) Registered Professional Land Surveyor Practice Test

(RPLS) Registered Professional Land Surveyor Practice Test

RPLS Quality Control Procedures 5