diydrones/ardupilot — pull request #751 by geeksville (2013-12-25 18:59:15+00:00)
Title: Copter: Split out prearm failures of low HDOP separately from !gps lock

On the iris list there was some confusion on why the copter was blinking
yellow but yet they had gps lock. This should help prevent confusion, by making it clear that
hdop is bad (rather than just bad gps pos)