Originally Posted by
Patanom
Thank you. I would like to know the threshold point of the runway. Why? There are many satellites arround the Earth, 3 navigational systems. But if somebody to try the "blind" landing by GPS/GLONASS/GALILEO only (w/o ILS) , it's the disaster.
The threshold (in Europe example) look like ED50 datum ( pic. in attachmemt). The latitude arc sec is constant (1852 m : 60 sec), but tne longitude arc sec is depended fm latitude, on 60 deg it is abt 1,5 less then on the equator.
I.e the transfomation coordinates (include altitude) are needed or no?
IIRC, threshold data (or intersection data) is used by some FMS' to do a last-minute update to the IRS position prior to letting it navigate on its own.