Describe the issue identified (if applicable)
Currently the Instrument_Position_Angles class only has y_axis_position_angle and z_axis_position_angle attributes. This is fine for instruments whose boresight is aligned with their $x$-axis, but in any other case, the position angle of the instrument's $+x$-axis can/should be specified (e.g., if the boresight is along $+z$, the relevant PAs would be x_axis_position_angle and y_axis_position_angle).
Describe the solution you'd like
Add/define x_axis_position_angle as a possible attribute, and maybe a rule to check that only two of the three *_axis_position_angles are used at once.
Describe alternatives you've considered
The only real valid alternative is to omit Instrument_Position_Angles from labels of instrument products whose boresight lies along their $y$- or $z$-axis, which is not ideal.
Describe the issue identified (if applicable) Currently the
Instrument_Position_Anglesclass only hasy_axis_position_angleandz_axis_position_angleattributes. This is fine for instruments whose boresight is aligned with their $x$-axis, but in any other case, the position angle of the instrument's $+x$-axis can/should be specified (e.g., if the boresight is along $+z$, the relevant PAs would bex_axis_position_angleandy_axis_position_angle).Describe the solution you'd like Add/define
x_axis_position_angleas a possible attribute, and maybe a rule to check that only two of the three*_axis_position_angles are used at once.Describe alternatives you've considered The only real valid alternative is to omit
Instrument_Position_Anglesfrom labels of instrument products whose boresight lies along their $y$- or $z$-axis, which is not ideal.LDD Dictionary Version Applies to 1.0.0.0
PDS4 IM Version At least 1.19.0.0, if not others
Need-by Date ≲May 2024
Additional context N/A