[amsat-bb] Re: Satellite Tracking?

Armando Mercado am25544 at triton.net
Thu Nov 3 09:04:33 PDT 2011

Hello Geoff,

The doppler method was used in the early days
of the space age, (and maybe still is).  It's a
neat bit of detective work.  Monitor the frequency
of the satellite, and determine the time of closest
approach.  From that you can determine the
speed and altitude.  Build up enough data points
and you can figure out the orbit.  Like you said,
the target doesn't need to cooperate, just transmit.

As with the latest cubesat launch, when there are
many objects, it takes several weeks to figure out
who's who.  This could be way around that problem.

73 Armando  N8IGJ

>Hi Armando et al,

>I don't know about the methods written up by Karl & James. For a long time 
>I've had a project using Doppler shift curves in the back of my mind 
>(the "target" doesn't need to cooperate). I have most of the hardware based 
>around my HPSDR box and a t'bolt frequency reference. The software hasn't 
>even progressed beyond ideas and algorithms. I haven't even picked a language 
>or development environment (one day).

>I can see a very accurate Doppler shift curve being useful in the early days 
>after a multiple cubesat launch. How accurate would you need to be to 
>pick "your" cubesat from the crowd? One pass? multiple passes?

>Anyway that's this morning's breakfast coffee ideas from me. Have fun 
>y'all :-).

>73 de Geoff vk2tfg (/3). 

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