Plain English Meaning

This note tells you the procedure can be flown without GPS, by using signals from two ground-based distance-measuring stations to keep the aircraft within 0.3 nautical miles of the intended path.

Full Definition

A chart or database notation indicating that an RNAV procedure may be flown using DME/DME position updating (two or more ground-based DME stations) to meet the Required Navigation Performance value of 0.3 nautical miles, in lieu of GPS. The aircraft's Flight Management System must be capable of DME/DME position determination and must have access to suitable DME station geometry along the procedure.

Context Anchor

Seen as a note on some , especially RNAV where DME/DME updating is allowed for .