Re: [Orekit Users] OreKit and DORIS-DIODE

[MAISONOBE Luc <luc.maisonobe@c-s.fr>]

w.grossman@ieee.org a écrit :

Hi Walter,

> Does OreKit have the functions (primarily observation partials) to process
> DORIS Doppler data?  What OreKit tools are likely to be useful?

Yes and no...

You should probably create a new class starting from the RangeRate measurement
and changing some parts. There is already a woway constructor  
parameter that can
be set to false, hence implementing one-way Doppler, which is  
basically what Doris
does. However, the RangeRate class implements it as a signal boing  
from spacecraft
to ground, time stamped at reception on ground, whereas Doris would be  
a signal going
from ground to spacecraft, time stamped at reception on spacecraft.  
Note that you
would need one "GroundStation" instance for each ground beacon (but  
they can of
course be reused in several measurements, so if you have 8000  
measurements from
50 ground beacons, you would have 50 instances of GroundStation only, and the
8000 instance of measurements would each reference one of these beacons.

I think modifying RangeRate to create a Doris measurement is quite easy. There
are many available support methods, and you simply have to follow the  
same logic
as in RangeRate. For example the signalTimeOfFlight method that is used to
compute the downlink time is also able to compute the uplink time in the Doris
case, juste changing the parameters.

If you decide to implement this measurement type, we would be thrilled if you
could contribute it to Orekit so it can be integrated in the main library!

best regards,
Luc