[aprssig] Satellite positions: FREQUENCY

Heikki Hannikainen hessu at hes.iki.fi
Tue Oct 18 12:20:50 CDT 2011

On Tue, 18 Oct 2011, Bob Bruninga wrote:

> These users have no maps and so conveying huge 3000 mile diameter satellite
> footprint OBJECTS are of no value.

I don't see much value in conveying the current position of the satellite, 
either. Especially if the satellite is not visible to the user Right Now 
(where the AZ might actually be useful).

> The HUMAN interface to the HT/Mobile FM satellite operator is just to see
> the "object" in his POSITION LIST and there it is displayed with a DISTANCE

I believe that's not quite true? The distance is going to be incorrect, 
and the elevation will not be shown (the mobiles/ht's don't calculate that 
for you, and I don't know if they even could, does the altitude format do 
big enough numbers anyway?).

The bearing can be transmitted in the message without worrying whether the 
position packet makes it through. If the satellite is not currently in 
view, the user probably wants to know the bearing where the satellite will 
appear at the time of the AOS. He couldn't care much about the *current* 
bearing unless the satellite is visible currently.

   - Hessu

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