Orbital Parameter Message¶

Main Classes¶

class odmpy.opm.Header(originator, opm_version='2.0'[, creation_date[, comment]])¶

Bases: odmpy.opm.KeywordContainer

OPM Header object.

Parameters:	opm_version (str) – CCSDS OPM version. creation_date (datetime-like object) – Creation date. Defaults to current time. originator (str) – Creating agency or operator. comment (str) – Single or multi-line comment.

class odmpy.opm.Metadata(object_name, object_id, center_name, ref_frame, time_system[, ref_frame_epoch[, comment]])¶

Bases: odmpy.opm.KeywordContainer

OPM Metadata object.

Parameters:

object_name (str) – Spacecraft name. object_id (str) – Object identifier. International Designator recommended. center_name (str) – Origin of reference frame. ref_frame (RefFrame) – Reference frame in which state is defined. time_system (TimeSystem) – Time system used for state vector, maneuver, and covariance data. ref_frame_epoch (datetime-like object) – Epoch of reference frame. comment (str) – Single or multi-line comment.

class odmpy.opm.DataBlockStateVector(epoch, x, y, z, x_dot, y_dot, z_dot[, comment])¶

Bases: odmpy.opm.DataBlock, odmpy.opm.KeywordContainer

State vector block for OPM data section.

Parameters:	epoch (datetime-like object) – Epoch of state vector. x (float) – \(x\) [km]. y (float) – \(y\) [km]. z (float) – \(z\) [km]. x_dot (float) – \(\dot{x}\) [km/s]. y_dot (float) – \(\dot{y}\) [km/s]. z_dot (float) – \(\dot{z}\) [km/s]. comment (str) – Single or multi-line comment.

Instance attributes:

name¶

If set, block will have comment containing name in the ASCII-formatted output. Otherwise, default description is used.

class odmpy.opm.DataBlockKeplerianElements(semi_major_axis, eccentricity, inclination, ra_of_asc_node, arg_of_pericenter, gm[, true_anomaly[, mean_anomaly[, comment]]])¶

Bases: odmpy.opm.DataBlock, odmpy.opm.KeywordContainer

Keplerian elements block for OPM data section.

Parameters:

semi_major_axis (float) – Semimajor axis [km]. eccentricity (float) – Eccentricity [–]. inclination (float) – Inclination [deg]. ra_of_asc_node (float) – Right ascension of the ascending node [deg]. arg_of_pericenter (float) – Argument of pericenter [deg]. true_anomaly (float) – True anomaly [deg]. mean_anomaly (float) – Mean anomaly [deg]. gm (float) – Gravitational coefficient [km3s-2] comment (str) – Single or multi-line comment.

Note

Either true_anomaly or mean_anomaly must be set before the block is validated (usually instigated by odmpy.opm.Opm)

Instance attributes:

name¶

If set, block will have comment containing name in the ASCII-formatted output. Otherwise, default description is used.

class odmpy.opm.DataBlockSpacecraftParameters(mass, solar_rad_area, solar_rad_coeff, drag_area, drag_coeff[, comment])¶

Bases: odmpy.opm.DataBlock, odmpy.opm.KeywordContainer

Spacecraft parameters block for OPM data section.

Parameters:	mass (float) – Spacecraft mass [kg]. solar_rad_area (float) – Solar radiation pressure area [m2]. solar_rad_coeff (float) – Solar radiation pressure coefficient [–]. drag_area (float) – Drag area [m2]. drag_coeff (float) – Drag coefficient [–]. comment (str) – Single or multi-line comment.

Instance attributes:

name¶

If set, block will have comment containing name in the ASCII-formatted output. Otherwise, default description is used.

class odmpy.opm.DataBlockCovarianceMatrix([comment[, cov_ref_frame[, **cargs]]])¶

Bases: odmpy.opm.DataBlock, odmpy.opm.KeywordContainer

Covariance matrix block for data section.

Parameters:

comment (str) – Single or multi-line comment. cov_ref_frame (RefFrame) – Covariance reference frame. cx_x (float) – \(x_{x}\) [km2]. cy_x (float) – \(y_{x}\) [km2]. cy_y (float) – \(y_{y}\) [km2]. cz_x (float) – \(z_{x}\) [km2]. cz_y (float) – \(z_{y}\) [km2]. cz_z (float) – \(z_{z}\) [km2]. cx_dot_x (float) – \(\dot{x}_{x}\) [km2s-1]. cx_dot_y (float) – \(\dot{x}_{y}\) [km2s-1]. cx_dot_z (float) – \(\dot{x}_{z}\) [km2s-1]. cx_dot_x_dot (float) – \(\dot{x}_\dot{x}\) [km2s-2]. cy_dot_x (float) – \(\dot{y}_{x}\) [km2s-1]. cy_dot_y (float) – \(\dot{y}_{y}\) [km2s-1]. cy_dot_z (float) – \(\dot{y}_{z}\) [km2s-1]. cy_dot_x_dot (float) – \(\dot{y}_\dot{x}\) [km2s-2]. cy_dot_y_dot (float) – \(\dot{y}_\dot{y}\) [km2s-2]. cz_dot_x (float) – \(\dot{z}_{x}\) [km2s-1]. cz_dot_y (float) – \(\dot{z}_{y}\) [km2s-1]. cz_dot_z (float) – \(\dot{z}_{z}\) [km2s-1]. cz_dot_x_dot (float) – \(\dot{z}_\dot{x}\) [km2s-2]. cz_dot_y_dot (float) – \(\dot{z}_\dot{y}\) [km2s-2]. cz_dot_z_dot (float) – \(\dot{z}_\dot{z}\) [km2s-2].

Note

Due to the large number of covariance parameters, the method signature accepts them as **cargs.

Instance attributes:

name¶

If set, block will have comment containing name in the ASCII-formatted output. Otherwise, default description is used.

class odmpy.opm.DataBlockManeuverParameters(man_epoch_ignition, man_duration, man_delta_mass, man_ref_frame, man_dv_1, man_dv_2, man_dv_3[, comment])¶

Bases: odmpy.opm.DataBlock, odmpy.opm.KeywordContainer

Maneuver parameters block for data section.

Parameters:

man_epoch_ignition (datetime-like object) – Epoch of ignition. man_duration (float) – Maneuver duration. [s] man_delta_mass (float) – Mass change during maneuver. [kg] man_ref_frame (RefFrame) – Coordinate system for velocity increment vector. man_dv_1 (float) – 1st component of velocity increment vector [km/s]. man_dv_2 (float) – 2nd component of velocity increment vector [km/s]. man_dv_3 (float) – 3rd component of velocity increment vector [km/s]. comment (str) – Single or multi-line comment.

Instance attributes:

name¶

If set, block will have comment containing name in the ASCII-formatted output. Otherwise, default description is used.

class odmpy.opm.Data(state_vector[, spacecraft_parameters[, keplerian_elements[, covariance_matrix[, maneuver_parameters]]]])¶

OPM Data object (mandatory).

Parameters:	state_vector (DataBlockStateVector) – State vector block spacecraft_parameters (DataBlockSpacecraftParameters) – Spacecraft parameters block keplerian_elements (DataBlockKeplerianElements) – Keplerian elements block covariance_matrix (DataBlockCovarianceMatrix) – Covariance matrix block maneuver_parameters (DataBlockManeuverParameters) – Maneuver parameters block

validate_blocks()¶

Ensure mandatory blocks are present, prerequisites fulfilled, and types checked.

Raises:	ValueError – if a given block is a list but repetition for the block type is disallowed. TypeError – if data block is not sublass of odmpy.opm.DataBlock or a valid list of them.

class odmpy.opm.Opm(header, metadata, data[, user_defined])¶

Represent complete OPM.

Parameters:	header – Instance of odmpy.opm.Header metadata – Instance of odmpy.opm.Metadata data – Instance of odmpy.opm.Data user_defined (dict) – User defined variables

output()¶

Return a line iterator for an ASCII-formatted OPM file.

write(fp)¶

Write ASCII-formatted OPM file to fp (a .write()-supporting file-like object)

class odmpy.opm.KeywordContainer¶

Base class of OPM keyword sections.

The standard splits an orbital parameter message file into different sections, which will subclass KeywordContainer.

The main purpose of the base class is to implement the methods for validating and formatting the list of keywords provided by each sublcass.

Inherited by:

• Header
• Metadata
• DataBlockStateVector
• DataBlockKeplerianElements
• DataBlockSpacecraftParameters
• DataBlockCovarianceMatrix
• DataBlockManeuverParameters

validate_keywords()¶

Ensures keywords are valid and set (if mandatory).

Raises:	odmpy.opm.MissingKeywordError – if a mandatory keyword is None ValueError – if keyword validation fails

This method should be called internally before data meant for output is produced.

class odmpy.opm.KeywordContainer

Base class of OPM keyword sections.

The standard splits an orbital parameter message file into different sections, which will subclass KeywordContainer.

The main purpose of the base class is to implement the methods for validating and formatting the list of keywords provided by each sublcass.

Inherited by:

• Header
• Metadata
• DataBlockStateVector
• DataBlockKeplerianElements
• DataBlockSpacecraftParameters
• DataBlockCovarianceMatrix
• DataBlockManeuverParameters

validate_keywords()

Ensures keywords are valid and set (if mandatory).

Raises:	odmpy.opm.MissingKeywordError – if a mandatory keyword is None ValueError – if keyword validation fails

This method should be called internally before data meant for output is produced.

Enums¶

class odmpy.opm.RefFrame¶

Reference frame.

EME2000

Earth Mean Equator and Equinox of J2000

GCRF

Geocentric Celestial Reference Frame

GRC

Greenwich Rotating Coordinates

ICRF

International Celestial Reference Frame

ITRF2000

International Terrestrial Reference Frame 2000

ITRF-93

International Terrestrial Reference Frame 1993

ITRF-97

International Terrestrial Reference Frame 1997

MCI

Mars Centered Inertial

TDR

True of Date, Rotating

TEME

True Equator Mean Equinox (see below)

TOD

True of Date

RSW

Another name for RTN

RTN

Radial, transverse, normal

TNW

A local orbital coordinate frame that has the x-axis along the velocity vector, W along the orbital angular momentum vector, and N completes the right handed system.

class odmpy.opm.TimeSystem¶

Time system.

GMST

Greenwich Mean Sidereal Time

GPS

Global Positioning System

MET

Mission Elapsed Time (note)

MRT

Mission Relative Time (note)

SCLK

Spacecraft Clock (receiver) (requires rules for interpretation in ICD)

TAI

International Atomic Time

TCB

Barycentric Coordinate Time

TDB

Barycentric Dynamical Time

TCG

Geocentric Coordinate Time

TT

Terrestrial Time

UT1

Universal Time

UTC

Coordinated Universal Time