Ephemeris Components

See also

Module OrbitEphemerisMessage

Module OEM Data Types

EphemerisSegment

class oem.components.EphemerisSegment(metadata, state_data, covariance_data=None, version='2.0')

Bases: object

OEM ephemeris segment.

Container for a single OEM ephemeris segment.

copy()

Create an independent copy of this instance.

covariances

Return list of Covariances in this segment.

has_accel

Evaluate if segment contains acceleration data.

has_covariance

Evaluate if segment contains covariance data.

resample(step_size, in_place=False)

Resample ephemeris data.

Replaces the existing ephemeris state data in this EphemerisSegment with a new list of states sampled at the desired sampling interval.

Parameters:
  • step_size (float) – Sample step size in seconds.
  • in_place (bool, optional) – Toggle in-place resampling. Default is False.
Returns:

Resampled EphemerisSegment. Output is

an indepdent instance if in_place is True.
Return type:

EphemerisSegment
states

Return list of States in this segment.

steps(step_size)

Sample Segment at equal time intervals.

This method returns a generator producing states at equal time intervals spanning the useable duration of the parent EphemerisSegment.

Parameters:step_size (float) – Sample step size in seconds.
Yields:State – Sampled state.

Examples

Sample states in each segment of an OEM at 60-second intervals:

>>> for segment in oem:
...    for state in segment.steps(60):
...        pass
useable_start_time

Return epoch of start of useable state data range

useable_stop_time

Return epoch of end of useable state data range

HeaderSection

class oem.components.HeaderSection(fields)

Bases: oem.base.KeyValueSection

OEM header section.

Container for a single OEM header section.

Examples

This class behaves similar to a dict allowing membership checks, iteration over keys, and value set/get.

>>> "CCSDS_OEM_VERS" in header:
True

>>> keys = [key for key in header]

>>> metadata["ORIGINATOR"] = 'ORIG_NAME'

>>> metadata["ORIGINATOR"]
'ORIG_NAME'
copy()

Create an independent copy of this instance.

version

MetaDataSection

class oem.components.MetaDataSection(metadata, version='2.0')

Bases: oem.base.KeyValueSection

OEM metadata section.

Container for a single OEM metadata section.

Examples

This class behaves similar to a dict allowing membership checks, iteration over keys, and value set/get.

>>> "OBJECT_NAME" in metadata:
True

>>> keys = [key for key in metadata]

>>> metadata["CENTER_NAME"] = 'Mars'

>>> metadata["CENTER_NAME"]
'Mars'
copy()

Create an independent copy of this instance.

useable_start_time

Return epoch of start of useable state data range

useable_stop_time

Return epoch of end of useable state data range

DataSection

class oem.components.DataSection(states, version='2.0')

Bases: object

OEM data section.

Container for a single OEM ephemeris state data section.

copy()

Create an independent copy of this instance.

has_accel

Evaluate if section contains acceleration data.

states

Return a list of States in this section.

CovarianceSection

class oem.components.CovarianceSection(covariances, version='2.0')

Bases: object

OEM covariance section.

Container for a single OEM covariance section.

copy()

Create an independent copy of this instance.

covariances

Return a list of covariances in this section.