[time-nuts] Time and frequency practical exercise 2018 late quarter; precision measure of 432mhz band Sat in Lunar Orbit

[jimlux]

On 11/17/17 5:16 PM, Hal Murray wrote:
> 
> kb8tq at n1k.org said:
>> Ok, 1 Hz at 437.5 MHZ is roughly 2 ppb. That is pretty much “slam dunk”
>> accuracy with a GPSDO. Much easier to obtain and set up in a school
>> environment. The key will be orbit estimation for the +/- doppler part of
>> it.  Orbit estimation is not quite a slam dunk sort of thing. The GPSDO
>> would also give accurate location. Even with good orbit data, the solution
>> still requires a good location estimate.
> 
> What is the orbital period?  It would be fun to plot the Doppler over time
> and see if you can get something that looks like a big chunk of an orbit.
> 
> Ugh.   What is the Doppler due to the Earth's rotation?
> 

not huge.. Earth is 40,000 km circumference (thank you Napoleon and the 
Cassinis), so at the equator the velocity is on the order of 500 m/s

Doppler is about 600 Hz from earth rotation.

1ppm at mid latitudes