'Trany' my idea of a HUD's was that it could/would be needed as a supplement to an App, to aid in the 'visual' aspect of any App,not used as a stand alone device, that's what I was alluding to:-).
As mentioned elsewhere here an ILS would be needed as it's an acceptable std world wide as a precision App & seeing as Cooly is an international drome (albeit almost a backward one) that's what we have to do to be like the real world outside the Aussie barbwire way of thinking:-)
Wmk2