Field Procedures & Data Collection Flashcards

What does an RTK GNSS survey require to get centimeter-level positions in real time?

Answer: A base station or network sending corrections to the rover over a data link

RTK needs real-time carrier-phase corrections from a base or network sent by radio or cellular link.

A GNSS receiver shows a high PDOP value. What does this indicate?

Answer: Poor satellite geometry and lower expected precision

Higher dilution of precision means satellites are poorly spread out, which weakens the solution.

What usually causes GNSS multipath error?

Answer: Signals reflecting off buildings, vehicles, or other surfaces near the antenna

Reflected signals take a longer path than direct signals and corrupt the measured range.

What elevation mask angle is commonly used to exclude low satellites in survey-grade GNSS work?

Answer: 10° to 15°

A 10–15° mask removes low satellites whose signals suffer the most atmospheric and multipath error.

When recording GNSS antenna height on a tripod, what is most important?

Answer: Recording the measurement type (slant or vertical) and the reference point measured to

The software needs to know how and where the height was measured to reduce it to the antenna reference point correctly.

In static GNSS surveying, how should session length relate to baseline length?

Answer: Longer baselines generally need longer observation sessions

Longer baselines have more uncorrelated atmospheric error, so more data is needed to resolve ambiguities reliably.

What does a "fixed" RTK solution mean compared to a "float" solution?

Answer: Integer carrier-phase ambiguities are resolved, giving centimeter-level precision

A fixed solution has resolved whole-cycle ambiguities, while a float solution is less precise, often decimeter-level.