heyoka.model.state_to_rsw_inertial

heyoka.model.state_to_rsw_inertial#

heyoka.model.state_to_rsw_inertial(*, pos: Iterable[expression], vel: Iterable[expression], r: Iterable[expression], v: Iterable[expression]) → tuple[list[expression], list[expression]]#

Convert state to the inertial RSW frame.

Added in version 7.9.0.

The inertial RSW is an inertial (i.e., non-rotating and non-translating) variant of the RSW frame, which is itself described in detail in the documentation of state_to_rsw().

Whereas the basis vectors \(\hat{\boldsymbol{R}}\), \(\hat{\boldsymbol{S}}\) and \(\hat{\boldsymbol{W}}\) are defined from r and v in the same way as in the standard RSW frame, they are assumed to be constant, and the origin is assumed to be fixed at r.

Consequently, transforming a position to the inertial RSW frame will yield the same result as the transformation to the standard RSW frame, but velocity transformations will produce different results.

Note

The inertial RSW frame is also known as RSW_INERTIAL and UVW. In certain contexts, the moniker RTN (which is usually an alias for the standard RSW frame) might refer to the inertial RSW frame (e.g., this is the case in the CCSDS CDM standard).

See also

https://sanaregistry.org/r/orbit_relative_reference_frames/

Parameters:

  • pos – the Cartesian position vector to be transformed.

  • vel – the Cartesian velocity vector to be transformed.

  • r – the Cartesian position of the origin of the RSW frame.

  • v – the Cartesian velocity of the origin of the RSW frame.

Returns:

pos and vel transformed in the inertial RSW reference frame defined by r and v.

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