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Re: [Orekit Users] DSSTPropagator isOsculating

I want to point out that the thread that was generated by Elisabet on 22 March is useful in understanding the java code for the DSST tesseral linear combination short-periodic terms.


Dr. Paul J. Cefola
Consultant in Aerospace Systems, Spaceflight Mechanics, & Astrodynamics
Adjunct Faculty, Dept. of Mechanical and Aerospace Engineering, University at Buffalo (SUNY)

4 Moonstone Way
Vineyard Haven, MA 02568

508-696-1884 (phone on Martha's Vineyard)
978-201-1393 (cell)


On 03/24/2016 5:01 am, MAISONOBE Luc wrote:
Elisabet <elisabet.cid-borobia@thalesaleniaspace.com> a écrit :


Luc, your code also works for me. The error occurs when the earthOrder is different from 0 in the UnnormalizedSphericalHarmonicsProvider. There is not any problem if : GravityFieldFactory.getUnnormalizedProvider(earthDegree,0);
However, it throws an arithmetic error when:

Could you verify this?

Still no problems.

When I call GravityFieldFactory.getUnnormalizedProvider(earthDegree,
earthOrder) with
earthOrder set to 4 (instead of forced to 0 as in my previous mail), I
 get this:

mean:       equinoctial parameters: {a: 7120000.0; ex:
-9.743700647852352E-4; ey: 2.2495105434386478E-4; hx:
0.39375193676896686; hy: 0.4222472565026574; lv: 179.0;}
osculating: equinoctial parameters: {a: 7119197.746018779; ex:
-7.268671251360758E-4; ey: 5.352135157065923E-4; hx:
0.3938711876441645; hy: 0.4221175844115694; lv: 178.98823442719726;}

So the osculating parameters are different from the previous ones,
which is expected.

I don't get any exceptions.

Could you send the full stack trace of the exception you get? What are
 the non-zero degree order you use?

With the current development code, I do get an exception when degree
and order are set to 2,
but it is an ArrayIndexOutOfBoundException, not an
ArithmeticException. I'll investigate
that one.

best regards,

Best regards,