RAIM Outage Prediction

Steve

Steve

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How common is this ?

(referring to today's prediction)

http://www.raimprediction.net/

terminal_nobaro.png
 
What do the colors mean? I assume green is good and red is bad. After all aren't Republicans red. I live in California but I usually vote with the daemons spawned by the Devil himself.

Joe
 
I never understood the idea of the "summary picture". I guess if you see green covering everywhere you plan to be, then you don't have to think about it any more.

But the way it works is that if there will be an outage, no matter how brief, in that "square" any time during the next N hours (it defaults to 18hrs) then that square will be colored red. So if you see red there, then you have to go to "playback mode" and find out when that outage will be. It may last 5 minutes, and be finished hours before you launch. And, of course, a RAIM outage doesn't mean a GPS outage, just a lack of sufficient redundancy to be trustworthy enough for GPS approaches.

So it's the nature of that depiction to seem a bit pessimistic. But that does seem like more red than I'm used to seeing on that chart.
-harry
 
The non-precision approach chart is even more impressive.

Run the playback on the charts model - 12 hour period covers an awful lot of the US.
 
Make sure you select Baro Aiding as all IFR GPS units use it. Even so, there are areas with problems.
 
WAAS LPV200 service is still not affected in CONUS and most of Alaska. There is a paucity of satellites up over Canada today.
 
Let'sgoflying! said:
That is why I am keeping Loran.
Once they realize the insanity that it was to destroy our only good D-> backup, they will reinstate it!
/wishful thinking
Click to expand...
Don't count on it. They'd spend billions developing a new system before they'd turn an old one back on.
 
It shouldn't be very common, but right now they are rephasing some of the satellites to get better coverage. The rephasing takes months and the in between state may not be good for coverage.
 
jesse said:
Don't count on it. They'd spend billions developing a new system before they'd turn an old one back on.
Click to expand...

We are already spending billions on the next system. Look up GPS III.
 
COFlyBoy said:
We are already spending billions on the next system. Look up GPS III.
Click to expand...

And on the radio this morning some dufe from ABC was all excited about how there are presently "24 satellites all around the world". Duh! And each one is all around the world every 90 minutes or so. These people never fail to amaze me at their level of stupidity.
 
jesse said:
Don't count on it. They'd spend billions developing a new system before they'd turn an old one back on.
Click to expand...

Someone already spent a pile of cash developing eLoran, a significant upgrade to LORAN-c.
 
gismo said:
Someone already spent a pile of cash developing eLoran, a significant upgrade to LORAN-c.
Click to expand...

Well, yeah, but to be fair, the essential core of that system is already in place, fully-functional and proven. Hence, no chance.
 
jesse said:
Don't count on it. They'd spend billions developing a new system before they'd turn an old one back on.
Click to expand...


$8 Billion Dollars Being Poured Into GPS

Prophetic, Jesse!


http://www.insidegnss.com/node/551
a full eLoran
system would cost up to $400 million more with an expected annual
allocation of $15–$25 million, Dubay said. Annual LORAN operations and
maintenance costs (as of FY06) are $45 million, a figure expected to
decline to a projected $22 million a year upon implementation of full
eLORAN system architecture with reduced staffing at automated stations.
 
Steve said:
How common is this ?
Click to expand...
Obviously there must be a time window associated with such "red" (unavailable from ..to ..). Is it seconds, minutes?
Those who have WAAS capable receivers are not subject to RAIM predictions/limitations but they must check NOTAMS related to WAAS.
On this website is the current status of WAAS, as of now it looks OK for the whole US, it is updated every 3 minutes. My G1000/IFR instructor told me that if there are WAAS outages they typically last short minutes or even seconds - you simply wait a minute or two and you can proceed. And WAAS outage doesn't mean GPS is unusable - it only means you can't fly precision GPS approaches.

http://www.nstb.tc.faa.gov/RT_VerticalProtectionLevel.htm
 
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