Relative Properties

Relative properties between two satellites.

class RelativeProperties(*rel_properties: dict[str, Any], chief_name: str, name='rel_props')

Bases: Observation

Include properties relative to another satellite.

Within the observation specification for the deputy satellite, this would look like.

obs.RelativeProperties(
    dict(prop="r_DC_N", norm=1e3),
    dict(prop="v_DC_N", norm=1e3),
    chief_name="ChiefSat",
),

Parameters:

• rel_properties (dict[str, Any]) –

  Property specifications. Properties are optionally normalized by some factor. Each observation is a dictionary with the keys:

  • prop: Name of a function in Relative Properties.

  • norm optional: Value to normalize property by. Defaults to 1.0.

  • name optional: Name of the observation element. Defaults to the value of prop.

  • fn optional: Alternatively, call a function that takes the deputy (self) and chief (other) as arguments.

• chief_name (str) – Name of the satellite to compare against.

• name – Name of the observation.

r_DC_N(deputy, chief)

Relative position of the deputy satellite to the chief satellite in inertial frame.

r_DC_C(deputy, chief)

Relative position of the deputy satellite to the chief satellite in chief body frame.

r_DC_D(deputy, chief)

Relative position of the deputy satellite to the chief satellite in deputy body frame.

r_DC_Hc(deputy, chief)

Relative position of the deputy satellite to the chief satellite in chief Hill frame.

r_DC_Hd(deputy, chief)

Relative position of the deputy satellite to the chief satellite in deputy Hill frame.

v_DC_N(deputy, chief)

Relative velocity of the deputy satellite to the chief satellite in inertial frame.

v_DC_C(deputy, chief)

Relative velocity of the deputy satellite to the chief satellite in chief body frame.

v_DC_D(deputy, chief)

Relative velocity of the deputy satellite to the chief satellite in deputy body frame.

v_DC_Hc(deputy, chief)

Relative velocity of the deputy satellite to the chief satellite in chief Hill frame.

v_DC_Hd(deputy, chief)

Relative velocity of the deputy satellite to the chief satellite in deputy Hill frame.

sigma_DC(deputy, chief)

Relative attitude of the deputy satellite to the chief satellite.

sigma_DHc(deputy, chief)

Relative attitude of the deputy satellite to the chief satellite in chief Hill frame.

sigma_HdC(deputy, chief)

Relative attitude of the deputy satellite Hill frame to the chief satellite.

sigma_HdHc(deputy, chief)

Relative attitude of the deputy satellite Hill frame to the chief satellite Hill frame.

rso_imaged_regions(servicer, chief, region_centers=array([[1, 0, 0], [-1, 0, 0], [0, 1, 0], [0, -1, 0], [0, 0, 1], [0, 0, -1]]), frame='chief_hill')

For use with the RSO tasking scenario.

Returns the fraction of regions imaged by the servicer, where regions are defined by the inspection points closest to each region center.

Parameters:

• servicer – The servicer satellite.

• chief – The chief satellite.

• region_centers – The centers of the regions to return inspection metrics for. It may be useful to set this as fibonacci_sphere points.

• frame – The frame to use for the region centers. Can be chief_hill or chief_body.