Elisabet, Tesseral terms can contribute multiple terms to the space object motion: 1. Deep resonant terms 2. Shallow resonant terms 3. Tesseral m-daily terms 4. Tesseral linear combination (short-periodic) termsIn the DSST (both GTDS and Standalone) in the initialization, the period of the resonant terms is compared with a parameter RESONPRD. The default for RESONPRD is 864000 sec or 10 days. If the period of the resonant terms is larger than RESONPRD, the terms are deemed to be resonant and they are included in the mean element equations of motion portion of the DSST.
If the period of the resonant terms is less than RESONPRD, the terms are considered to be short-periodic terms.
It must be that for the default Orekit DSST LEO test case, the tesseral terms do not contribute to the resonant motion.
In GTDS DSST and in the Standalone F77 DSST, RESONPRD is an input parameter. It should be considered if RESONPRD should be an input to the Orekit DSST?
I am attaching a paper that I co-authored with Ron Proulx in 1991 on DSST and Shallow Resonant orbits. Particularly, I vector you to the discussion at the bottom of p. 4. This has application to speeding up the DSST when tesseral perturbations are included.
The derivation on pp. 9 to 11 is also important. regards, Paul -- Dr. Paul J. Cefola Consultant in Aerospace Systems, Spaceflight Mechanics, & AstrodynamicsAdjunct Faculty, Dept. of Mechanical and Aerospace Engineering, University at Buffalo (SUNY)
4 Moonstone Way Vineyard Haven, MA 02568 USA 508-696-1884 (phone on Martha's Vineyard) 978-201-1393 (cell) paulcefo@buffalo.edu paul.cefola@gmail.com On 03/29/2016 5:08 am, Elisabet wrote:
Hello,I have another question concerning the DSST propagator. I propagated the mean elements of the orbit and I discovered that the Earth’s potential order has not got any impact. I propagated the orbit using a 36x36 Earth’s potential and a 36x0 Earth’s potential and the results were the same. I would like to know why the results remain constant or why the order does not affect the results?Best regards, Elisabet
Attachment:
AAS_91-139_Shallow_Resonance.pdf
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