What are the most suitable elevation masks for differential GPS surveys?

For differential GPS surveys, the selection of elevation masks is crucial to ensure reliable satellite signal quality and accuracy of position measurements. An elevation mask specifies the minimum angle at which satellites are utilized for navigation calculations, helping to filter out signals from satellites that may be lower on the horizon and subject to greater atmospheric interference and multipath errors.

Using a 10° elevation mask at the base station allows for the inclusion of satellites that are sufficiently above the horizon, balancing between having enough satellites for an accurate fix while minimizing degradation in signal quality from those observed at very low angles. When setting a slightly higher mask of 15° at the subordinate station, this helps to further enhance the quality of the differential correction since signals from lower elevation satellites can introduce more error due to atmospheric effects and multipath issues.

Thus, a configuration with a 10° mask at the base station captures an adequate number of satellites without compromising signal integrity, while the 15° mask at the subordinate station provides a buffer that optimizes signal quality for corrections. This combination is effective in enhancing the overall accuracy and reliability of the GPS survey data collected.