Spectra Precision Survey Pro v4.5 Ranger Reference Manual - Manual (Page 177)

Survey Menu – Conventional Mode
R-169
Sky Plot
(available only when using GeoLock)
Survey Remote Control Sky Plot
The Sky Plot screen displays the relative location of the visible
satellites in the sky, as well as if they are being used to calculate a
position.
Satellites with a usable signal are shown with
red flashing indicators.
The Elevation Mask is the minimum angle
above the horizon where locked satellites are
used for a solution. This area is indicated on
the screen by the inner circle.