Does GNSS surveying provide accurate Z (vertical) recordings?

GNSS (Global Navigation Satellite System) surveying is indeed capable of providing accurate vertical (Z) recordings, making it a valuable tool for hydrographic surveying. The satellites used in GNSS systems transmit signals that allow surveyors to determine precise locations in three dimensions: latitude, longitude, and elevation. The accuracy of vertical measurements typically depends on several factors such as the quality of the satellite signals, the type of GNSS equipment used, and the positioning algorithms employed.

When GNSS is used under optimal conditions, it can achieve vertical accuracy within a few centimeters, which is generally sufficient for many surveying applications, including hydrographic surveys. Moreover, advancements in satellite technology and correction services—including Differential GNSS (DGNSS) and Real-Time Kinematic (RTK) positioning—further enhance vertical accuracy by correcting systematic errors and providing real-time adjustments.

Considering this capability, option C correctly states that GNSS provides accurate readings for vertical measurements, making it an essential tool in the field of hydrographic surveying.