What is the recommended elevation mask when tracking satellites in differential GPS?

In differential GPS (DGPS), the recommended elevation mask for tracking satellites is typically set at about 10 degrees. The elevation mask is crucial because it determines the cutoff angle for satellite signals; satellites below this angle are often obscured by the horizon or are subject to more atmospheric interference, resulting in less reliable data.

Setting the mask at 10 degrees helps ensure that the GPS receiver is only utilizing signals from satellites that are higher in the sky, where they are less affected by obstacles such as buildings, trees, or atmospheric disturbances. This leads to improved accuracy and reliability of the position fixes provided by the GPS system. It's a fine balance; a lower mask might allow more satellites to be tracked, but these signals are often less reliable, while a higher mask might exclude useful satellites that could improve positioning. Thus, the 10-degree elevation mask is considered a standard compromise that optimizes usability and accuracy in DGPS applications.