[time-nuts] BYMLBI (Back Yard Medium LBI)

Chris Albertson albertson.chris at gmail.com
Sat Mar 19 18:24:29 UTC 2011


On Fri, Mar 18, 2011 at 8:31 PM, jimlux <jimlux at earthlink.net> wrote:
>
>> That's an interesting idea, but I think all the orbit data for GPS
>> satellites
>> is Earth relative rather than star relative.  I wonder if the group that
>> drives the GPS satellites even knows their location relative to the stars.
>> I'll bet not.
>>
>
> I'll bet they do. Lots of earth orbiting satellites use star trackers for
> position determination.

Star trackers or Sun sensors are used for pointing, They measure
rotation but not position.   It is at least conceptually  easy to
measure a GPS sat's location if you have a GPS receiver at a surveyed
location.  And also they have access to the encrypted military band we
don't so they can correct for atmospheric effects.    I think in
addition the GPS sats get observed optically too
>
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-- 
=====
Chris Albertson
Redondo Beach, California



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