[time-nuts] Slow death of Waas 48

[Magnus Danielson]

On 07/07/2010 08:11 AM, Said Jackson wrote:
> Hi guys,
>
> Waas sat 48 (prn 135) is still going strong, much longer than originally forecasted - it is experiencing a complete avionics failure as you may know.
>
> Has anyone set up tests to see how it's eventual demise may affect timing accuracy?
>
> One of our FireFly-1A boards can be monitored in realtime here and we can see that waas 48 is still going strong:
>
>    http://www.jackson-labs.com/images/gpsstat.htm
>
> All of our FireFly units are waas enabled by default.
>
> the operators are desperately trying to kill the sat to avoid interference with other sats as it aimlessly drifts about into the field of view of other geos', so at some point we may see it cut off suddenly.
>
> We will monitor the events here. If the waas firmware in our gps receivers works properly I wouldn't expect any impact. But who knows, software bugs could seriously affect especially airplanes landing in instrument conditions relying on proper waas operations..
>
> Btw: I am surprised that we haven't even seen a drop in C/No on the sat yet..

If it still has power, oriented in the right direction (antennas down) 
and they keep beaming signals to it, it will work. If they don't beam 
signals into it, it would still sit there and broadcast, so they might 
as well use it. The best thing for them would be a loss of orientation 
control if not a complete power failure would save them. If it spins, it 
will get less power and less amount of time it would be facing the earth 
with it's noise transmissions.

Cheers,
Magnus