org.orekit.files.ccsds.ndm.adm.aem

Class AemWriter

java.lang.Object

org.orekit.files.ccsds.utils.generation.AbstractMessageWriter<Header,AemSegment,Aem>

org.orekit.files.ccsds.ndm.adm.aem.AemWriter

All Implemented Interfaces:

MessageWriter<Header,AemSegment,Aem>

public class AemWriter
extends AbstractMessageWriter<Header,AemSegment,Aem>

A writer for Attitude Ephemeris Messsage (AEM) files.

Metadata

The AEM header and metadata used by this writer are described in the following tables. 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: AdmMetadataKey.OBJECT_NAME, AdmMetadataKey.OBJECT_ID, AemMetadataKey.START_TIME and AemMetadataKey.STOP_TIME. The usage column in the table indicates where the metadata item is used, either in the AEM header or in the metadata section at the start of an AEM attitude segment.

The AEM header for the whole AEM file is set when calling AbstractMessageWriter.writeHeader(Generator, Header), the entries are defined in table 4-2 of the ADM standard.

AEM metadata

Keyword	Mandatory	Default in Orekit
CCSDS_AEM_VERS	Yes	CCSDS_AEM_VERS
HeaderKey.COMMENT	No	empty
HeaderKey.CREATION_DATE	Yes	Now
HeaderKey.ORIGINATOR	Yes	AbstractMessageWriter.DEFAULT_ORIGINATOR

The AEM metadata for the AEM file is set when calling writeSegmentContent(Generator, double, AemSegment), the entries are defined in tables 4-3, 4-4 and annex A of the ADM standard.

AEM metadata

Keyword	Mandatory	Default in Orekit
MetadataKey.COMMENT	No	empty
AdmMetadataKey.OBJECT_NAME	Yes
AdmMetadataKey.OBJECT_ID	Yes
AdmMetadataKey.CENTER_NAME	No
AemMetadataKey.REF_FRAME_A	Yes
AemMetadataKey.REF_FRAME_B	Yes
AemMetadataKey.ATTITUDE_DIR	Yes
MetadataKey.TIME_SYSTEM	Yes
AemMetadataKey.START_TIME	Yes	default to propagation start time (for forward propagation)
AemMetadataKey.USEABLE_START_TIME	No
AemMetadataKey.USEABLE_STOP_TIME	No
AemMetadataKey.STOP_TIME	Yes	default to propagation target time (for forward propagation)
AemMetadataKey.ATTITUDE_TYPE	Yes	QUATERNION/RATE
AemMetadataKey.QUATERNION_TYPE	No	FIRST
AemMetadataKey.EULER_ROT_SEQ	No
AemMetadataKey.RATE_FRAME	No	REF_FRAME_B
AemMetadataKey.INTERPOLATION_METHOD	No
AemMetadataKey.INTERPOLATION_DEGREE	No	always set in AemMetadata

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 AdmMetadataKey.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:

10.2

Author:

Bryan Cazabonne

Field Summary

Fields

Modifier and Type	Field and Description
static double	CCSDS_AEM_VERS Version number implemented.
static 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 and Description
AemWriter(IERSConventions conventions, DataContext dataContext, AbsoluteDate missionReferenceDate) Constructor used to create a new AEM 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 and Description
void	writeSegmentContent(Generator generator, double formatVersion, AemSegment segment) Write one segment content (without XML wrapping).

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

getContext, getDefaultVersion, getTimeConverter, 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 Detail

CCSDS_AEM_VERS

public static final double CCSDS_AEM_VERS

Version number implemented.

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 Detail

AemWriter

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

Constructor used to create a new AEM 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.

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

Method Detail

writeSegmentContent

public void writeSegmentContent(Generator generator,
                                double formatVersion,
                                AemSegment segment)
                         throws IOException

Write one segment content (without XML wrapping).

Specified by:

writeSegmentContent in class AbstractMessageWriter<Header,AemSegment,Aem>

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