[time-nuts] Home made GPS disciplined atomic clock

[Bruce Griffiths]

Esa Heikkinen wrote:
>> One test you can perform that should give an indication of the location
>> of the Allan intercept is to:
>>     
>
> Ok, thanks for your clear instructions!
>
> My test periods have been much too short, if the Kalman filter learning 
> takes even days! But with these instructions I'lll get better data for 
> OCXO vs. LPRO comparison and maybe also the OCXO health.
>
>   
>> Ulrich's Plotter is good for this
>>     
>
> Hmm. Is that software available somewhere?
> No luck with quick Google tour...
>
>   
>> However to do this successfully your antenna will need a good view of
>> the sky.
>>     
>
> And that's also one of my problems here. Many trees in the yard. No 
> problems with normal "hand GPS" reception but when it comes to these 
> timing systems this could be one explanation of these strange timing 
> changes at satellite "hops" already noted. However the antenna sees most 
> of the sky clearly but not so close to horizon. Will the Northen 
> position (Lat 62.33302) also cause inaccuracy to GPS?
>
>   
Esa

You'll need a good view of the sky to the south where the GPS SVs will
be located.

You'll also need to set the elevation mask appropriately.
Multipath will be more problematic with low elevation SVs.

It would also be helpful if you plot the SV tracks across the sky (as
seen by a GPS receiver) as this will show if and where obstructions are
significant.
There's a lot of software out there for doing this.



Bruce