Estimates of Local Sky Obstruction (Regions of Problematic GPS Reception)

Some possible approaches

r.angle.sh (see image below and attached script) r.mapcalc "$GIS_OPT_output = atan( ($GIS_OPT_elev - $z) / sqrt( (x() - $x)^2 + (y() - $y)^2) )"

Angle Map: Vertical angle (degrees) from starting point (yellow point) to each cell.

Compute percent of visible terrain that is above 10 degrees vertical elevation at each cell, using r.los.

Percent of visible terrain obscuring the sky above 10 degrees