sensor elevation angle derivations

1. sensor elevation angle from sensor zenith angle

   symbol	description	unit	variable name
   \(\alpha_{S}\)	sensor elevation angle	\(deg\)	sensor_elevation_angle {:}
   \(\theta_{S}\)	sensor zenith angle	\(deg\)	sensor_zenith_angle {:}

   The pattern : for the dimensions can represent {time}, or no dimensions at all.

   \[\alpha_{S} = 90 - \theta_{S}\]