Création de CovarianceDisplay authored by Julien LEBLOND's avatar Julien LEBLOND
This page describes the content of a CZML document. Please read [Get Started](Get-Started) for an explanation of how a CZML document is put together.
# Covariance Display
**Implements** : [CzmlPrimaryObject](CZMLPrimaryObjects) **Extends** : [AbstractPrimaryObject](AbstractPrimaryObject)
**Example** :
```json
{
"id":"COV/Keplerian parameters: {a: 7878000.0; e: 0.0; i: 20.0; pa: 0.0; raan: 0.0; v: 0.0;}[2460384:43200 UTC (03/15/2024 00:00:00), 2460384:43260 UTC (03/15/2024 00:01:00), 2460384:43320 UTC (03/15/2024 00:02:00), 2460384:43380 UTC (03/15/2024 00:03:00), 2460384:43440 UTC (03/15/2024 00:04:00), 2460384:43500 UTC (03/15/2024 00:05:00), 2460384:43560 UTC (03/15/2024 00:06:00), 2460384:43620 UTC (03/15/2024 00:07:00), 2460384:43680 UTC (03/15/2024 00:08:00), 2460384:43740 UTC (03/15/2024 00:09:00)]",
"name":"Covariance of Keplerian parameters: {a: 7878000.0; e: 0.0; i: 20.0; pa: 0.0; raan: 0.0; v: 0.0;}",
"orientation":{
"interval":"2024-03-15T00:00:00Z/2024-03-15T05:00:00Z",
"epoch":"2024-03-15T00:00:00Z",
"unitQuaternion":[
0,0.11569062798938476,0.12952604257194286,0.6509835902071016,-0.7389580828248281,
60,0.11943577277304293,0.12608039801805412,0.632361993372306,-0.754955057441116,
120,0.12307773148000348,0.12252573594575572,0.6133475316353406,-0.7704830442530984,
180,0.12661339981222997,0.11886509438917287,0.593951991730508,-0.785532410434607,
240,0.13003976644592383,0.11510160480621578,0.5741873930795629,-0.8000938178377701,
300,0.13335391475857142,0.11123848993382857,0.5540659835669867,-0.814158226409187
],
"interpolationAlgorithm":"LAGRANGE",
"interpolationDegree":5
},
"position":{
"reference":"Keplerian parameters: {a: 7878000.0; e: 0.0; i: 20.0; pa: 0.0; raan: 0.0; v: 0.0;}#position"
},
"ellipsoid":{
"fill":false,
"outline":true,
"outlineColor":{
"rgba":[
0,255,0,255
]
},
"slicePartitions":24,
"stackPartitions":36,
"interval":"2024-03-15T00:00:00Z/2024-03-15T05:00:00Z",
"radii":{
"epoch":"2024-03-15T00:00:00Z",
"cartesian":[
0,999.9999999999995,100.00000000000001,99.99999999999994,
60,1000.3557088442701,101.24416119580226,100.06558092587828,
120,1001.4188533345995,105.00577034773143,100.26155105418857,
180,1003.1789072897213,111.37161616179563,100.58560099177218,
240,1005.6231038323383,120.48430803609354,101.03391142817493,
300,1008.7436529447372,132.53872099231185,101.60118284669117
]
}
}
}
```
# Properties
**id** - String : Identification of the covariance display object, *default* : "COV/{id of the object}".
**name** - String : Name of the covairance display, _default_ : "Covariance of {name of the object}".
**availability** - [TimeInterval](https://cesium.com/learn/cesiumjs/ref-doc/TimeInterval.html) : Time interval when the covariance display is displayed.
## Intrinsic arguments :
These arguments can be used to build a satellite object :
**satellite** - [Satellite](Satellite) : The satellite which the covariance display will be around.
**initCovariance** - [StateCovariance](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/propagation/StateCovariance.html) : An initial state covariance object to give the propagation of the covariance a initialisation.
**lof** - [LOF](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/frames/LOF.html) : The local orbital frame of the satellite.
**color** - [Color](https://docs.oracle.com/javase/8/docs/api/java/awt/Color.html) : The color of the ellipsoid used to represents the covariance.
**oem** - [Oem](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/files/ccsds/ndm/odm/oem/Oem.html) : An Orekit Oem file used as an input.
**ephemeris** - [List of TimeStampedPVCoordinates](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/files/ccsds/ndm/odm/oem/OemData.html#getEphemeridesDataLines()) : A list of TimeStampedPVCoordinates extracted from an Oem or another file, to get the ephemeris.
**position** - [Position](Position) : The absolute position of the ellipsoid built with the position object.
**ellipsoid** - [CzmlEllipsoid](CzmlEllipsoid) : The czml ellipsoid object used to built the ellipsoid to be displayed that represents the covariance.
**attitude** - [Attitude](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/attitudes/Attitude.html) : The attitude of the ellipsoid built with an Orkeit Attitude object.
## Other parameters
**referenceFrame** - String : The reference frame where the covariance is computed, *default* : "INERTIAL".
**positionReference** - [Reference](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/attitudes/Attitude.html) : The reference for the center of the position of the ellipsoid.
**orientationReference** - [Reference](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/attitudes/Attitude.html) : The reference for the orientation of the ellipsoid.
**allSpaceCraftState** - [List of SpacecraftState](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/propagation/SpacecraftState.html) : A list of all the spacecraft state when the covariance is propagated.
**ellipsoidList** - [List of CzmlEllipsoid](CzmlEllipsoid) : When the covariance changes in time, several ellipsoids are computed, they are stored here.
**julianDates ** - [List of JulianDate](https://cesium.com/learn/cesiumjs/ref-doc/JulianDate.html) : A list of all the julian dates when the propagation of the covariance is computed.
**dimensionsOfEllipsoids** - [List of Cartesian](https://github.com/AnalyticalGraphicsInc/czml-writer/wiki/Cartesian3Value) : A list of cartesian that represents the radius of the ellipsoids in the ITR frame.
**attitudes* - [List of Attitude](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/attitudes/Attitude.html) : A list of all the attitudes of all the ellipsoids, when the ellipsoid changes in time.
**satelliteCartesianList** - [List of Cartesian](https://github.com/AnalyticalGraphicsInc/czml-writer/wiki/Cartesian3Value) : A list that contains all the position in cartesian of the satellite in the ITR frame.
**timeScale** - [TimeScale](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/time/TimeScale.html) : The time scale used for the covariance
**uniqueEllipsoid** - [CzmlEllipsoid](CzmlEllipsoid) : The ellipsoid used when only one ellipsoid is needed.
# Build
The CovarianceDisplay object can be build with :
* A [satellite](Satellite), an[initCovariance](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/propagation/StateCovariance.html), a [lof](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/frames/LOF.html) :
```java
CovarianceDisplay covariance = new CovarianceDisplay(satellite, initCovariance, lof);
```
* A [satellite](Satellite), an[initCovariance](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/propagation/StateCovariance.html), a [lof](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/frames/LOF.html), a [color](https://docs.oracle.com/javase/8/docs/api/java/awt/Color.html) :
```java
CovarianceDisplay covariance = new CovarianceDisplay(satellite, initCovariance, lof, color);
```
* An [oem](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/files/ccsds/ndm/odm/oem/Oem.html), a [lof](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/frames/LOF.html) :
```java
CovarianceDisplay covariance = new CovarianceDisplay(oem, lof);
```
* An [oem](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/files/ccsds/ndm/odm/oem/Oem.html), a [lof](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/frames/LOF.html), a [color](https://docs.oracle.com/javase/8/docs/api/java/awt/Color.html) :
```java
CovarianceDisplay covariance = new CovarianceDisplay(oem, lof, color);
```
* An [ephemeris](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/files/ccsds/ndm/odm/oem/OemData.html#getEphemeridesDataLines()), an
[initCovariance](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/propagation/StateCovariance.html), a [lof](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/frames/LOF.html) :
```java
CovarianceDisplay covariance = new CovarianceDisplay(ephemeris, initCovariance, lof);
```
* An [ephemeris](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/files/ccsds/ndm/odm/oem/OemData.html#getEphemeridesDataLines()), an
[initCovariance](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/propagation/StateCovariance.html), a [lof](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/frames/LOF.html), a [color](https://docs.oracle.com/javase/8/docs/api/java/awt/Color.html) :
```java
CovarianceDisplay covariance = new CovarianceDisplay(ephemeris, initCovariance, lof, color);
```
* A [position](Position), an [ellipsoid](CzmlEllipsoid), an [attitude](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/attitudes/Attitude.html) :
```java
CovarianceDisplay covariance = new CovarianceDisplay(position, ellipsoid, attitude);
```
* An id, a name, a [position](Position), an [ellipsoid](CzmlEllipsoid), an [attitude](https://www.orekit.org/site-orekit-development/apidocs/org/orekit/attitudes/Attitude.html) :
```java
CovarianceDisplay covariance = new CovarianceDisplay(id, name, position, ellipsoid, attitude);
```
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