Horizontal Survey Point (All except End Fire Type GS): Center of Antenna Supporting Structure
Vertical Survey Point (All except End Fire Type GS): The intersection of the ground, gravel, concrete pad, or other base and a plumb line through the Horizontal Survey Point.
Horizontal Survey Point (End Fire Type GS): Phase Center Reference Point
Vertical Survey Point (End Fire Type GS): Phase Center Reference Point

ILS GlideSlope	ILS GlideSlope	ILS GlideSlope	ILS GlideSlope and TMOM
ILS GlideSlope (rare type)	ILS GlideSlope (end fire type)