Brilliant - that was the sort of explanation I was hoping for. Thank you.
Now I dont understand what the RAIM predictor is doing in my G1000.
Is it using barometric pressure when the system is predicting non baro outages and if it is how do I know it is? Is there any indication from the inbuilt RAIM prediction. Presumably during the period the of predicted non baro outages the aircraft bound system will report reliance on only three satellites?