Package org.orekit.files.ccsds.ndm.odm.oem

Class OemWriter

java.lang.Object

org.orekit.files.ccsds.utils.generation.AbstractMessageWriter<OdmHeader,OemSegment,Oem>

org.orekit.files.ccsds.ndm.odm.oem.OemWriter

All Implemented Interfaces:

MessageWriter<OdmHeader,OemSegment,Oem>

public class OemWriter
extends AbstractMessageWriter<OdmHeader,OemSegment,Oem>

A writer for Orbit Ephemeris Message (OEM) files.

Metadata

The OEM metadata used by this writer is described in the following table. Many metadata items are optional or have default values so they do not need to be specified. At a minimum the user must supply those values that are required and for which no default exits: OdmMetadataKey.OBJECT_NAME, and CommonMetadataKey.OBJECT_ID. The usage column in the table indicates where the metadata item is used, either in the OEM header or in the metadata section at the start of an OEM ephemeris segment.

OEM metadata

Keyword	Usage	Obligatory	Default	Reference
CCSDS_OEM_VERS	Header	Yes	Oem.FORMAT_VERSION_KEY	Table 5-2
COMMENT	Header	No		Table 5-2
HeaderKey.CREATION_DATE	Header	Yes	Now	Table 5.2, 6.5.9
HeaderKey.ORIGINATOR	Header	Yes	AbstractMessageWriter.DEFAULT_ORIGINATOR	Table 5-2
OdmMetadataKey.OBJECT_NAME	Segment	Yes		Table 5-3
CommonMetadataKey.OBJECT_ID	Segment	Yes		Table 5-3
CommonMetadataKey.CENTER_NAME	Segment	Yes		Table 5-3
CommonMetadataKey.REF_FRAME	Segment	Yes		Table 5-3, Annex A
CommonMetadataKey.REF_FRAME_EPOCH	Segment	No		Table 5-3, 6.5.9
MetadataKey.TIME_SYSTEM	Segment	Yes
OemMetadataKey.START_TIME	Segment	Yes		Table 5-3, 6.5.9
OemMetadataKey.USEABLE_START_TIME	Segment	No		Table 5-3, 6.5.9
OemMetadataKey.STOP_TIME	Segment	Yes		Table 5-3, 6.5.9
OemMetadataKey.USEABLE_STOP_TIME	Segment	No		Table 5-3, 6.5.9
OemMetadataKey.INTERPOLATION	Segment	No		Table 5-3
OemMetadataKey.INTERPOLATION_DEGREE	Segment	No		Table 5-3

The MetadataKey.TIME_SYSTEM must be constant for the whole file and is used to interpret all dates except HeaderKey.CREATION_DATE which is always in UTC. The guessing algorithm is not guaranteed to work so it is recommended to provide values for CommonMetadataKey.CENTER_NAME and MetadataKey.TIME_SYSTEM to avoid any bugs associated with incorrect guesses.

Standardized values for MetadataKey.TIME_SYSTEM are GMST, GPS, MET, MRT, SCLK, TAI, TCB, TDB, TT, UT1, and UTC. Standardized values for reference frames are EME2000, GTOD, ICRF, ITRF2000, ITRF-93, ITRF-97, LVLH, RTN, QSW, TOD, TNW, NTW and RSW. Additionally ITRF followed by a four digit year may be used.

Since:

9.0

Author:

Hank Grabowski, Evan Ward

See Also:

• CCSDS 502.0-B-2 Orbit Data Messages
• CCSDS 500.0-G-4 Navigation Data Definitions and Conventions
• StreamingOemWriter

Field Summary

Fields

Modifier and Type	Field	Description
static final double	CCSDS_OEM_VERS	Version number implemented.
static final String	DEFAULT_FILE_NAME	Default file name for error messages.
static final int	KVN_PADDING_WIDTH	Padding width for aligning the '=' sign.

Fields inherited from class org.orekit.files.ccsds.utils.generation.AbstractMessageWriter

DEFAULT_ORIGINATOR

Constructor Summary

Constructors

Constructor	Description
OemWriter(IERSConventions conventions, DataContext dataContext, AbsoluteDate missionReferenceDate)	Constructor used to create a new OEM writer configured with the necessary parameters to successfully fill in all required fields that aren't part of a standard object.

Method Summary

Modifier and Type	Method	Description
protected void	writeSegmentContent(Generator generator, double formatVersion, OemSegment segment)	Write one segment content (without XML wrapping).

Methods inherited from class org.orekit.files.ccsds.utils.generation.AbstractMessageWriter

getContext, getDefaultVersion, getFormatVersionKey, getRoot, getTimeConverter, getVersion, setContext, writeFooter, writeHeader, writeSegment

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.orekit.files.ccsds.utils.generation.MessageWriter

writeMessage

Field Details

CCSDS_OEM_VERS

public static final double CCSDS_OEM_VERS

Version number implemented.

See Also:

• Constant Field Values

DEFAULT_FILE_NAME

public static final String DEFAULT_FILE_NAME

Default file name for error messages.

See Also:

• Constant Field Values

KVN_PADDING_WIDTH

public static final int KVN_PADDING_WIDTH

Padding width for aligning the '=' sign.

See Also:

• Constant Field Values

Constructor Details

OemWriter

public OemWriter(IERSConventions conventions,
 DataContext dataContext,
 AbsoluteDate missionReferenceDate)

Constructor used to create a new OEM writer configured with the necessary parameters to successfully fill in all required fields that aren't part of a standard object.

If the mandatory header entries are not present (or if header is null), built-in defaults will be used

The writer is built from the complete header and partial metadata. The template metadata is used to initialize and independent local copy, that will be updated as new segments are written (with at least the segment start and stop will change, but some other parts may change too). The template argument itself is not changed.

Calling this constructor directly is not recommended. Users should rather use writerBuilder.buildOemWriter().

Parameters:

conventions - IERS Conventions

dataContext - used to retrieve frames, time scales, etc.

missionReferenceDate - reference date for Mission Elapsed Time or Mission Relative Time time systems

Since:

11.0

See Also:

• DEFAULT_FILE_NAME

Method Details

writeSegmentContent

protected void writeSegmentContent(Generator generator,
 double formatVersion,
 OemSegment segment)
                            throws IOException

Write one segment content (without XML wrapping).

Specified by:

writeSegmentContent in class AbstractMessageWriter<OdmHeader,OemSegment,Oem>

Parameters:

generator - generator to use for producing output

formatVersion - format version to use

segment - segment to write

Throws:

IOException - if any buffer writing operations fails