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RE: [Orekit Developers] Semi-analytic DSST propagation

Hi Luc,

Thank you for your answer.

The propagation is performed over [tStart + dt, tEnd +dt] for several values of dt. For each dt, a range of impulsive maneuvers (dv1, dv2...) occurring in the interval is considered. Thus, for a given dt, several propagations are done over the same interval, but with a changing  impulsive shot magnitude/direction.

Hope this helps.

Regards,
Brian

-----Original Message-----
From: orekit-developers-request@orekit.org [mailto:orekit-developers-request@orekit.org] On Behalf Of Luc Maisonobe
Sent: lundi 12 octobre 2015 15:33
To: orekit-developers@orekit.org
Subject: Re: [Orekit Developers] Semi-analytic DSST propagation

Le 12/10/2015 16:28, JOUANNIC Brian a écrit :
> Hi,

Hi Brian,

> 
>  
> 
> I have a question concerning the use of the semi-analytic propagator 
> implemented in Orekit.
> 
>  
> 
> As this kind of propagator is known to reduce the CPU load at an 
> acceptable precision cost, I wanted to use it in an algorithm 
> involving a large number of short propagations (typically over a 
> couples of
> orbits) instead of a numerical propagator.
> 
>  
> 
> However, it seems that for repeated short term propagations, a 
> NumericalPropagator performs better (in terms of computation time) 
> than a DSSTPropagator. From my understanding, it looks like this is 
> due to the fact the initialize() function of the TesseralContribution 
> class is called at the beginning of each propagation, causing the 
> algorithm to spend about 50% of CPU time in this function.
> 
>  
> 
> It is possible that I am not using the DSSTPropagator properly and 
> that is why I am asking you whether you could help me on that matter.

Are all your propagations related to the same orbit or do they correspond to different initial states?
Are your propagation in sequence (say t0 -> t1, then t1 -> t2, ...) or do they correspond to different evaluations over the same range?

best regards,
Luc

> 
>  
> 
> Regards,
> 
> Brian
>