NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: GPS System failure
From: Greg R_
Date: 2014 Jun 22, 18:31 -0700
On 6/18/2014 6:21:06 AM, Jeremy C (noreply_jeremyc@fer3.com) wrote:
> Greg,
>
> Time was approximately 1800Z (2100 local) on 14 June. Lat 31-
> 49'N Long 34-37'E I am not sure if Ashdod, Israel has an airport, but Tel
> Aviv airport isn't too far away.
> Thanks for the information. I didn't
> know about that. I
> didn't get any broadcasts about known outages and didn't look at the birds
> from the GNSS as I was trying to get the alarms to stop. I will have to
> keep an eye out for similar problems.
>
> Jeremy
>
>
>
> [link: 'http://fer3.com/arc/m2.aspx/GPS-System-failure-JeremyC-jun-2014-g28079']
From: Greg R_
Date: 2014 Jun 22, 18:31 -0700
I setup a waypoint ("J") based on your lat/long,
and created a flight plan from Tel Aviv (LLBG) to that waypoint. I then ran that
flight plan through Garmin's FDE (Fault Detection and Exclusion) program with an
up to date almanac and an ETA at J of 1800Z on 06/14/2014.
According to those results (see attachments), the
GPS availability was OK for IFR (Instrument Flight Rules) at the time (and for
all currently available options of varying precision for approach and
landing). And that would seem to imply
that it was also good for marine navigation (especially since aviation use
requires 1 additional working satellite for 3D navigation). Though I'm not sure that this is a valid apples-to-apples
comparison, you might want to search online to see if there were any GPS
advisories in effect at the time for marine use.
Is it possible that all 3 antennas were
obstructed at the time (i.e. someone working or lazing in the vicinity at the
time)? I'd ask what you saw on the satellites page of the GPSes, but think you
said that you weren't able to get that at the time.
--
GregR
On 6/18/2014 6:21:06 AM, Jeremy C (noreply_jeremyc@fer3.com) wrote:
> Greg,
>
> Time was approximately 1800Z (2100 local) on 14 June. Lat 31-
> 49'N Long 34-37'E I am not sure if Ashdod, Israel has an airport, but Tel
> Aviv airport isn't too far away.
> Thanks for the information. I didn't
> know about that. I
> didn't get any broadcasts about known outages and didn't look at the birds
> from the GNSS as I was trying to get the alarms to stop. I will have to
> keep an eye out for similar problems.
>
> Jeremy
>
>
>
> [link: 'http://fer3.com/arc/m2.aspx/GPS-System-failure-JeremyC-jun-2014-g28079']
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