Sat Jan 29, 2022 12:33 pm
#1896265
flyer5 wrote:
The impression I get is RAIM takes calculations from several combinations and draws conclusions about which single satellite might be suspect. If it can see 6 satellites it can determine a correct fix, and potentially exclude the rogue satellite from further calculations.
However if the GPS is taking an average of all the fixes then I don't see why you need RAIM. With high numbers of satellites in view, the plain average would surely be pretty good even with the duff one in the calculation.
I wonder if anyone knows how this works in practice. Does SkyDemon just take a simple position output from the device or does it have access to individual fixes? Do typical devices take averages of all available satellites? Do typical devices do RAIM of any sort?
We're at risk of comparing apples with pears here: If you are on an IFR flighplan, planning to carry out a PBN (formerly RNAV) approach at your destination, you are obliged to check RAIM availability at your destination during a small window either side of your ETA: This can be done online, but most navigation systems (EG Garmin 430W - the W is crucial) will do it for you:
Pete S as was
‘Work in progress’.
‘Work in progress’.