Dme Dme Update
On some ILS charts we can read a note "DME reads 0 at threshold." What I understand from this, the DME position is electronically displaced. So, the actual position of the airplane with reference to the geographical position of DME antenna and measure of the distance from antenna for position updating, will be different. If I am correct, this will cause the DME-DME position updating to be erroneous and eventually map/position shift will occur. To prevent from this, when we see this note on the approcah, we should select that DME station to be inhibited from position updating.
What you guys think all above this?