Treating final integration time as differential algebra variable

Orekit usage
1

Hi all,

I am trying to build a tool that computes both the “time of closest approach” (TCA) and the “distance of closest approach” (DCA) of two spacecraft with respect to each other, using Orekit built-in functionality for Taylor Differential Algebra (to deal with uncertainty in initial conditions). The value of TCA, however, changes for every pair of new initial conditions around a nominal value. This is solved in bibliography by initializing the final time of integration as a DA (differential algebra) variable, and then evaluating the propagated polynomial for several values of the final integration time. Is there any way this can be done using orekit/hipparchus libraries with some modifications?

Thank you in advance. Regards,
mviturro

2

Hi @mviturro,

Have you tried the following constructor of FieldAbsoluteDate to build the final time of integration ?
The idea would be to use input T elapsedDuration as your DA variable representing the duration of the propagation.

Regards,
Maxime

3

This seems to work wonders for now. Thank you very much!