GNSS RTK System

Comparison of Static GNSS and GNSS RTK from a Field Survey Deployment Perspective

GNSS has become the primary tool for topographic surveying and construction layout thanks to its ability to determine coordinates based on satellite signals. At the beginning of a project, choosing between static GNSS and GNSS RTK often directly affects field organization, data acquisition time, and post-processing workflow.

Both methods use the same satellite foundation but differ in signal acquisition, processing approach, and application objectives.

Static GNSS focuses on long observation sessions to reduce random errors

Static GNSS places receivers at fixed survey control points for a sufficiently long duration to accumulate carrier phase data. This observation period typically ranges from several tens of minutes to several hours, depending on the distance between points and satellite visibility conditions.

When data is collected continuously, errors caused by atmospheric effects, multipath interference, or signal fluctuations are handled through post-processing. Processing software uses simultaneous data from multiple receivers to recompute the coordinates of each point based on error models.

This method is commonly used during the stage of establishing control networks or creating primary reference points for the entire project. Field time is longer, but the results remain consistent with geodetic standards.

One important consideration is that static observation requires an installation position with clear satellite visibility. High-rise buildings, dense tree canopies, or narrow terrain can increase multipath effects and extend observation time.

GNSS RTK processes signals in real time using correction data

Unlike static observation, GNSS RTK operates with a real-time processing model. One receiver is installed as the base station, while the remaining receivers act as rovers that move between survey points.

The base station receives satellite signals and transmits correction data to the rover through radio or internet communication. The rover directly processes carrier phase data and displays coordinates immediately on the controller.

With real-time processing capability, RTK is suitable for detailed surveys, alignment layout, and as-built measurements. Results can be verified directly at the field site instead of waiting for post-processing.

However, this method depends heavily on the stability of correction data transmission. When communication signals are interrupted or satellite conditions change rapidly, the solution status may become unstable and require remeasurement.

Where does the major difference between these methods lie?

The difference between static GNSS and RTK lies in deployment strategy rather than hardware.

Static observation requires pre-established control points, fixed receiver placement, and long observation sessions. Data processing is performed after completing field measurements.

RTK prioritizes flexibility. A survey team can move continuously between multiple points without waiting for data accumulation. This significantly increases measurement efficiency across large areas.

In many infrastructure projects, the two methods are commonly combined. Control networks are established using static GNSS, and detailed measurements are then performed using RTK to shorten field operation time.

Environmental errors affect the two methods differently

GNSS signals are influenced by atmospheric conditions, signal reflection, and satellite obstruction. Static observation benefits from long sessions that reduce these effects through averaging.

RTK processes data in real time, making it more sensitive to environmental changes. When obstacles appear or correction transmission becomes unstable, the solution status can be interrupted.

For this reason, surveys in urban or industrial areas often require checking satellite status before deploying RTK.

Selecting the measurement method based on project objectives

Reference control surveys, control networks, or projects requiring very small coordinate tolerances typically use static GNSS. Detailed topographic surveys, construction layout, and as-built measurements are usually performed with RTK to increase operational speed.

GNSS equipment supporting both methods is currently distributed by EMIN Vietnam with multiple configurations suitable for topographic surveying and construction applications. Popular models such as Hi-Target V200 or SATLAB SL700 support multi-constellation tracking and tilt compensation, enabling flexible operation in obstructed environments.

Static GNSS and GNSS RTK share the same satellite foundation but differ in data acquisition and processing approaches. The measurement method should be defined before selecting equipment configuration instead of selecting hardware first and then building the survey workflow.

This approach helps maintain consistency across preparation, field deployment, and post-processing stages.