OREKIT

https://www.orekit.org/site-orekit-13.1.4/apidocs/
Admin
OREKIT is a low-level Java library for space mechanics projects, providing a common base layer for...
Tokens:3,751,241
Snippets:39,474
Trust Score:8.5
Update:3 months ago
Show doc for...
Tokens:
Raw
### create

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/propagation/events/FieldAbstractDetector.html

Build a new instance.

```APIDOC
## create

### Description
Build a new instance.

### Parameters
* `detectionSettings` (FieldEventDetectionSettings<T>) - detection settings
* `newHandler` (FieldEventHandler<T>) - event handler to call at event occurrences

### Returns
D - a new instance of the appropriate sub-type

### Since
12.2
```

--------------------------------

### Get Seconds Since Day Start from GLONASSDate

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/time/GLONASSDate.html

Get the number of seconds since the start of the day (Na start) for the GLONASS date.

```java
public double getSecInDay()

```

--------------------------------

### create

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/propagation/events/ElevationDetector.html

Build a new instance.

```APIDOC
## create
```java
protected ElevationDetector create(EventDetectionSettings detectionSettings, EventHandler newHandler)
```
### Description
Build a new instance.

### Specified by
`create` in class `AbstractDetector<ElevationDetector>`

### Parameters
* `detectionSettings` - detection settings
* `newHandler` - event handler to call at event occurrences

### Returns
a new instance of the appropriate sub-type
```

--------------------------------

### Get Segment Start Year

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/files/iirv/IIRVSegment.html

Retrieves the start year of the ephemeris segment.

```java
public
int getStartYear()
```

--------------------------------

### Setup Matrices Computation - Java

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/propagation/Propagator.html

Sets up the computation of the State Transition Matrix and Jacobians matrix with respect to parameters. This is useful for sensitivity analysis.

```java
setupMatricesComputation(String stmName,                         RealMatrix initialStm,                         DoubleArrayDictionary initialJacobianColumns)
```

--------------------------------

### Get Start Date Driver

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/propagation/events/FieldParameterDrivenDateIntervalDetector.html

Retrieves the parameter driver associated with the start date of the interval. This driver's value influences the interval's start.

```java
public DateDriver getStartDriver()
```

--------------------------------

### Get Seconds in GNSS Week

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/time/GNSSDate.html

Get the number of seconds elapsed since the start of the current GNSS week.

```java
public double getSecondsInWeek()
```

--------------------------------

### Create and Use IIRVFileWriter

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/files/iirv/IIRVFileWriter.html

Demonstrates the process of creating an IIRVBuilder, configuring it with metadata, creating an IIRVFileWriter, building an IIRVEphemerisFile, and writing it to disk.

```java
 // 1. Create an IIRVBuilder class to define the spacecraft/mission metadata values
 IIRVBuilder iirvBuilder = new IIRVBuilder(TimeScalesFactory.getUTC());
 iirvBuilder.setSupportIdCode(1221);
 iirvBuilder.setDragCoefficient(2.2);
 iirvBuilder.setOriginIdentification(OriginIdentificationTerm.GSFC);
 iirvBuilder.setRoutingIndicator("MANY");
 // ... (additional fields here)

 // 2. Create an IIRVFileWriter with the builder object
 IIRVFileWriter writer = new IIRVFileWriter(iirvBuilder, IIRVMessage.IncludeMessageMetadata.ALL_VECTORS);

 // 3. Generate an IIRVEphemerisFile containing the ephemeris data
 IIRVEphemerisFile iirvFile = iirvBuilder.buildEphemerisFile(coordinates);

 // 4. Write to disk. Recommendation: embed the start year in the filename (year does not appear in the IIRV itself)
 String testFilename = "TestSatellite" + "_" +
      iirvFile.getStartYear() + "_" +
      iirvFile.getIIRV().get(0).getDayOfYear().toEncodedString() + "_" +
      iirvFile.getIIRV().get(0).getVectorEpoch().toEncodedString() + ".iirv";
 writer.write(testFilename, iirvFile);
  
```

--------------------------------

### setupMatricesComputation

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/propagation/Propagator.html

Sets up the computation of the State Transition Matrix and Jacobians with respect to parameters. This allows for retrieval of these matrices during and after propagation.

```APIDOC
## setupMatricesComputation

### Description
Set up computation of State Transition Matrix and Jacobians matrix with respect to parameters. If this method is called, both State Transition Matrix and Jacobians with respect to the force models parameters that will be selected when propagation starts will be automatically computed, and the harvester will allow to retrieve them. The arguments for initial matrices _must_ be compatible with the `orbit type` and `position angle` that will be used by the propagator. The default implementation throws an exception as the method is not supported by all propagators.

### Parameters
- `stmName` (String) - State Transition Matrix state name
- `initialStm` (RealMatrix) - initial State Transition Matrix ∂Y/∂Y₀, if null (which is the most frequent case), assumed to be 6x6 identity
- `initialJacobianColumns` (DoubleArrayDictionary) - initial columns of the Jacobians matrix with respect to parameters, if null or if some selected parameters are missing from the dictionary, the corresponding initial column is assumed to be 0

### Returns
harvester to retrieve computed matrices during and after propagation

### Since
11.1
```

--------------------------------

### Get Milliseconds in GNSS Week

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/time/GNSSDate.html

Get the number of milliseconds elapsed since the start of the current GNSS week.

```java
public double getMilliInWeek()
```

--------------------------------

### Get Start Date of Propagation

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/propagation/FieldAbstractPropagator.html

Protected method to retrieve the start date of the propagation. This is useful for internal state management.

```java
protected FieldAbsoluteDate<T> getStartDate()
```

--------------------------------

### startStreaming

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/gnss/metric/ntrip/NtripClient.html

Connects to a specified mount point and begins streaming data.

```APIDOC
## startStreaming

### Description
Connect to a mount point and start streaming data from it.

### Parameters
* **mountPoint** (String) - the mount point to connect to
* **type** (Type) - the type of data to stream
* **requiresNMEA** (boolean) - true if NMEA sentences are required for authentication, false otherwise
* **ignoreUnknownMessageTypes** (boolean) - true to ignore unknown message types, false to throw an exception
```

--------------------------------

### setUpStmAndJacobianGenerators

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/propagation/integration/AbstractIntegratedPropagator.html

Sets up State Transition Matrix and Jacobian matrix handling.

```APIDOC
## setUpStmAndJacobianGenerators

### Description
Set up State Transition Matrix and Jacobian matrix handling.

### Method
`protected void setUpStmAndJacobianGenerators() `

```

--------------------------------

### Get Validity Start Date

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/gnss/attitude/BeidouMeo.html

Retrieves the start date of validity for this attitude provider. This method is specified by the GNSSAttitudeProvider interface.

```java
public AbsoluteDate validityStart()
```

--------------------------------

### Duty Cycle Phase Start Angle

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/files/ccsds/ndm/odm/ocm/OrbitManeuverHistoryMetadata.html

Methods to get and set the phase angle at the start of a duty cycle pulse.

```APIDOC
## getDcPhaseStartAngle

### Description
Get phase angle of pulse start.

### Method
```java
public double getDcPhaseStartAngle()
```

### Parameters
None

### Returns
phase angle of pulse start

## setDcPhaseStartAngle

### Description
Set phase angle of pulse start.

### Method
```java
public void setDcPhaseStartAngle(double dcPhaseStartAngle)
```

### Parameters
#### Path Parameters
* **dcPhaseStartAngle** (double) - Required - phase angle of pulse start
```

--------------------------------

### startStreaming

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/gnss/metric/ntrip/NtripClient.html

Connects to a specified mount point and begins streaming data, setting up an internal thread for continuous monitoring.

```APIDOC
## startStreaming

### Description
Connect to a mount point and start streaming data from it. This method sets up an internal dedicated thread for continuously monitoring data incoming from a mount point. When new complete `parsed messages` becomes available, the `observers` that have been registered using `addObserver()` method will be notified about the message. This method must be called once for each stream to monitor.

### Method
void

### Parameters
#### Path Parameters
- **mountPoint** (String) - mount point providing the stream
- **type** (Type) - messages type of the mount point
- **requiresNMEA** (boolean) - if true, the mount point requires a NMEA GGA sentence in the request
- **ignoreUnknownMessageTypes** (boolean) - if true, unknown messages types are silently ignored
```

--------------------------------

### Get Ephemeris Start Date

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/files/ccsds/ndm/adm/acm/AcmSatelliteEphemeris.html

Retrieves the start date of the attitude ephemeris for the satellite. This method is specified by the SatelliteAttitudeEphemeris interface.

```java
public AbsoluteDate getStart()
```

--------------------------------

### init Methods

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/propagation/class-use/SpacecraftState.html

Methods to initialize force models at the start of propagation, using an initial SpacecraftState.

```APIDOC
## init

### Description
Initialize the force model at the start of propagation.

### Method Signature
`void init(SpacecraftState initialState, AbsoluteDate target)`
```

--------------------------------

### Get Validity Start Date

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/estimation/measurements/QuadraticClockModel.html

Returns the start date of the model's validity period. Implements the ClockModel interface.

```java
public AbsoluteDate getValidityStart()
```

--------------------------------

### setUpStmAndJacobianGenerators

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/propagation/numerical/NumericalPropagator.html

Sets up the handling for State Transition Matrix and Jacobian matrix generation.

```APIDOC
## setUpStmAndJacobianGenerators

### Description
Set up State Transition Matrix and Jacobian matrix handling.

### Method Signature
```java
protected void setUpStmAndJacobianGenerators()
```
```

--------------------------------

### Constructor

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/models/earth/troposphere/AskneNordiusModel.html

Initializes a new AskneNordiusModel instance with a mapping function and a pressure, temperature, and humidity provider.

```java
public AskneNordiusModel(TroposphereMappingFunction mappingFunction,
                         PressureTemperatureHumidityProvider pthProvider)
```

--------------------------------

### Station.getValidFrom

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/time/class-use/AbsoluteDate.html

Gets the start of validity for station data.

```APIDOC
## AbsoluteDate getValidFrom()

### Description
Get start of validity.

### Returns
* AbsoluteDate - The start date of validity.
```

--------------------------------

### initStates Method

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/propagation/integration/AbstractGradientConverter.html

Initializes the first state with zero parameters.

```APIDOC
## initStates Method

### Description
Initialize first state with 0 parameters.

### Parameters
* **zeroParametersState** (FieldSpacecraftState<Gradient>) - state with zero parameters

Since: 11.2
```

--------------------------------

### ParseInfo.getStartDate

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/time/class-use/AbsoluteDate.html

Gets the start date from parsing information.

```APIDOC
## protected AbsoluteDate getStartDate()

### Description
Get start date.

### Returns
* AbsoluteDate - The start date.
```

--------------------------------

### Constructor

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/models/earth/atmosphere/HarrisPriester.html

Initializes the Modified Harris-Priester atmosphere model with a density table and cosine exponent.

```APIDOC
## Constructor

### Description
Initializes the Modified Harris-Priester atmosphere model.

### Parameters
* `sun` - The sun position.
* `earth` - The earth body shape.
* `tabAltRho` - The density table, where:
    * `tabAltRho[][0]` = altitude (m)
    * `tabAltRho[][1]` = min density (kg/m³)
    * `tabAltRho[][2]` = max density (kg/m³)
The altitude must be increasing. The internal density table is a copy of the provided one.
* `n` - The cosine exponent. Recommended values range from 2 (low inclination orbits) to 6 (polar orbits).
```

--------------------------------

### AcmSatelliteEphemeris.getStart

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/time/class-use/AbsoluteDate.html

Gets the start date of the satellite ephemeris.

```APIDOC
## AcmSatelliteEphemeris.getStart

### Description
Get the start date of the ephemeris.

### Method Signature
`AbsoluteDate getStart()`
```

--------------------------------

### Setup Matrices Computation - Java

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/propagation/Propagator.html

Configures the propagator to compute State Transition Matrices (STM) and Jacobians with respect to parameters. Requires compatible initial matrices and a dictionary for parameter columns.

```java
default MatricesHarvester setupMatricesComputation(String stmName,
                                                   RealMatrix initialStm,
                                                   DoubleArrayDictionary initialJacobianColumns)
```

--------------------------------

### Get Start Driver

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/propagation/events/ParameterDrivenDateIntervalDetector.html

Retrieves the date driver for the start of the interval. This driver enables dynamic control over the interval's beginning.

```java
DateDriver getStartDriver()
```

--------------------------------

### Get Ephemeris Start Date

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/files/ilrs/CPF.CPFEphemeris.html

Retrieves the start date of the ephemeris. This method is specified by multiple interfaces including EphemerisFile.EphemerisSegment and EphemerisFile.SatelliteEphemeris.

```java
public	AbsoluteDate	getStart()
```

--------------------------------

### SystemConfiguration Constructor

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/files/ilrs/CRDConfiguration.SystemConfiguration.html

Initializes a new instance of the SystemConfiguration class.

```APIDOC
## SystemConfiguration()

### Description
Constructor.

### Method
`public SystemConfiguration()`
```

--------------------------------

### Duty Cycle Execution Start Time

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/files/ccsds/ndm/odm/ocm/OrbitManeuverHistoryMetadata.html

Methods to get and set the start time of the initial duty cycle-based maneuver execution.

```APIDOC
## getDcExecStart

### Description
Get the start time of initial duty cycle-based maneuver execution.

### Method
```java
public AbsoluteDate getDcExecStart()
```

### Parameters
None

### Returns
start time of initial duty cycle-based maneuver execution

## setDcExecStart

### Description
Set the start time of initial duty cycle-based maneuver execution.

### Method
```java
public void setDcExecStart(AbsoluteDate dcExecStart)
```

### Parameters
#### Path Parameters
* **dcExecStart** (AbsoluteDate) - Required - start time of initial duty cycle-based maneuver execution
```

--------------------------------

### init Method

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/control/indirect/adjoint/FieldCartesianAdjointDerivativesProvider.html

Initializes the provider at the start of propagation.

```APIDOC
## init Method

### Description
Initialize the generator at the start of propagation.

### Specified by
`init` in interface `FieldAdditionalDerivativesProvider<T extends CalculusFieldElement<T>>`

### Parameters
- **initialState** (FieldSpacecraftState<T>) - initial state information at the start of propagation
- **target** (FieldAbsoluteDate<T>) - date of propagation
```

--------------------------------

### setupMatricesComputation

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/propagation/semianalytical/dsst/DSSTPropagator.html

Sets up the computation of the State Transition Matrix (STM) and the Jacobians matrix with respect to parameters. If invoked, these matrices will be automatically computed and accessible via the harvester. The initial matrices provided must be compatible with the propagator's orbit type and position angle.

```APIDOC
## setupMatricesComputation

### Description
Set up computation of State Transition Matrix and Jacobians matrix with respect to parameters. If this method is called, both State Transition Matrix and Jacobians with respect to the force models parameters that will be selected when propagation starts will be automatically computed, and the harvester will allow to retrieve them. The arguments for initial matrices _must_ be compatible with the `orbit type` and `position angle` that will be used by the propagator.

### Method
public DSSTHarvester setupMatricesComputation(String stmName, RealMatrix initialStm, DoubleArrayDictionary initialJacobianColumns)

### Parameters
* **stmName** (String) - State Transition Matrix state name
* **initialStm** (RealMatrix) - initial State Transition Matrix ∂Y/∂Y₀, if null (which is the most frequent case), assumed to be 6x6 identity
* **initialJacobianColumns** (DoubleArrayDictionary) - initial columns of the Jacobians matrix with respect to parameters, if null or if some selected parameters are missing from the dictionary, the corresponding initial column is assumed to be 0

### Returns
harvester to retrieve computed matrices during and after propagation
```

--------------------------------

### Convert Start Detector to Field Detector

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/forces/maneuvers/trigger/StartStopEventsTrigger.html

Converts a primitive firing start detector into its field-based equivalent. This is a skeleton implementation example.

```java
protected <D extends FieldEventDetector<S>, S extends CalculusFieldElement<S>> D convertStartDetector(final Field<S> field, final XyzDetector detector) {

        final FieldAbsoluteDate<S> date  = new FieldAbsoluteDate<>(field, detector.getDate());
        final S                    param = field.getZero().newInstance(detector.getParam());

        final D converted = (D) new FieldXyzDetector<>(date, param)
        .withDetectionSettings(field, detector.getDetectionSettings());
        return converted;

    }
```

--------------------------------

### SatelliteAntenna.getValidFrom

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/time/class-use/AbsoluteDate.html

Method to get the start of validity for a satellite antenna.

```APIDOC
## SatelliteAntenna.getValidFrom

### Description
Gets the start date of validity for the satellite antenna's specifications.

### Method

- `AbsoluteDate getValidFrom()`
```

--------------------------------

### init (FieldSpacecraftState)

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/forces/radiation/RadiationPressureModel.html

Initializes the force model at the start of propagation using a FieldSpacecraftState.

```APIDOC
## init

### Description
Initialize the force model at the start of propagation.

### Parameters
* `initialState` (FieldSpacecraftState<T>) - spacecraft state at the start of propagation.
* `target` (FieldAbsoluteDate<T>) - date of propagation.
```

--------------------------------

### init Method

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/forces/empirical/PolynomialAccelerationModel.html

Initializes the acceleration model at the start of the propagation.

```APIDOC
## init Method

### Description
Initialize the acceleration model at the start of the propagation.

### Parameters
* **initialState** (SpacecraftState) - spacecraft state at the start of propagation.
* **target** (AbsoluteDate) - date of propagation. Not equal to `initialState.getDate()`.
```

--------------------------------

### getStart

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/estimation/measurements/generation/AbstractMeasurementBuilder.html

Gets the start date of the measurement time span.

```APIDOC
## getStart

### Description
Gets the start of the measurements time span.

### Method Signature
```java
protected AbsoluteDate getStart()
```

### Returns
* **AbsoluteDate** - The start of the measurements time span.
```

--------------------------------

### Get Start Transition

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/utils/FieldTimeSpanMap.Span.html

Access the transition event that marks the beginning of this time span. Returns null if the span starts at past infinity.

```java
public FieldTimeSpanMap.Transition<S, F> getStartTransition()
```

--------------------------------

### Initialization and Step Handling Methods

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/estimation/sequential/SemiAnalyticalMeasurementHandler.html

Methods for initializing the handler and processing steps during propagation.

```java
public void init(SpacecraftState s0,
                 AbsoluteDate t)
```

```java
public void handleStep(OrekitStepInterpolator interpolator)
```

--------------------------------

### Get Split Seconds in GNSS Week

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/time/GNSSDate.html

Get the number of seconds elapsed since the start of the current GNSS week, represented as a TimeOffset object.

```java
public TimeOffset getSplitSecondsInWeek()
```

--------------------------------

### Initialize and Configure TimeSpanDragForce

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/forces/drag/TimeSpanDragForce.html

Demonstrates how to initialize a TimeSpanDragForce with an initial drag model and add subsequent models valid for specific time intervals. It also shows how to name parameter drivers for better tracking.

```java
TimeSpanDragForce force = new TimeSpanDragForce(atmosphere, isotropicDrag0);
force.addDragSensitiveValidAfter(isotropicDrag1, date.shiftedBy(Constants.JULIAN_DAY));
force.addDragSensitiveValidAfter(isotropicDrag2, date.shiftedBy(2 * Constants.JULIAN_DAY));
```

--------------------------------

### Get Start of Time Span

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/utils/FieldTimeSpanMap.Span.html

Retrieve the start date of this time span. If the span extends to past infinity, it returns the representation of past infinity.

```java
public FieldAbsoluteDate<F> getStart()
```

--------------------------------

### Initialization Methods using AbsoluteDate

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/time/class-use/AbsoluteDate.html

Demonstrates methods that initialize acceleration models or force models using AbsoluteDate.

```APIDOC
## init

### Description
Initializes the acceleration model or force model at the start of propagation.

### Method Signature
`void init(SpacecraftState initialState, AbsoluteDate target)`

### Parameters
- `initialState` (SpacecraftState) - The initial state of the spacecraft.
- `target` (AbsoluteDate) - The target date for initialization.
```

--------------------------------

### Constructor

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/estimation/iod/IodLambert.html

Creates an instance of IodLambert.

```APIDOC
## IodLambert(double mu)

### Description
Creator.

### Parameters
* `mu` (double) - gravitational constant
```

--------------------------------

### Get Ephemeris Segment Start Date

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/files/general/AttitudeEphemerisFile.AttitudeEphemerisSegment.html

Returns the start date of the current attitude ephemeris segment. Useful for time-based processing or segment identification.

```java
AbsoluteDate getStart()

```

--------------------------------

### DSSTPropagator.setupMatricesComputation

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/propagation/semianalytical/dsst/class-use/DSSTHarvester.html

Sets up the computation of the State Transition Matrix and Jacobian matrices.

```APIDOC
## Method: setupMatricesComputation

### Description
Sets up computation of State Transition Matrix and Jacobians matrix with respect to parameters.

### Signature
`DSSTHarvester setupMatricesComputation(String stmName, RealMatrix initialStm, DoubleArrayDictionary initialJacobianColumns)`

### Parameters
- **stmName** (String) - The name of the State Transition Matrix.
- **initialStm** (RealMatrix) - The initial State Transition Matrix.
- **initialJacobianColumns** (DoubleArrayDictionary) - The initial Jacobian columns.
```

--------------------------------

### AbstractSinex.getFileEpochStartTime

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/time/class-use/AbsoluteDate.html

Gets the start time of the file epoch for a SINEX file.

```APIDOC
## AbsoluteDate getFileEpochStartTime()

### Description
Get the file epoch start time.

### Returns
* AbsoluteDate - The start time of the file epoch.
```

--------------------------------

### Constructor

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/estimation/sequential/SemiAnalyticalUnscentedKalmanModel.html

Initializes a new instance of the SemiAnalyticalUnscentedKalmanModel.

```APIDOC
## SemiAnalyticalUnscentedKalmanModel

### Description
Unscented Kalman process model constructor (package private).

### Parameters
* `propagatorBuilder` (DSSTPropagatorBuilder) - propagators builders used to evaluate the orbits.
* `covarianceMatrixProvider` (CovarianceMatrixProvider) - provider for covariance matrix
* `estimatedMeasurementParameters` (ParameterDriversList) - measurement parameters to estimate
* `measurementProcessNoiseMatrix` (CovarianceMatrixProvider) - provider for measurement process noise matrix
```

--------------------------------

### AttitudeStateHistory.getStart

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/time/class-use/AbsoluteDate.html

Gets the start date of an attitude state history segment.

```APIDOC
## AttitudeStateHistory.getStart

### Description
Get the start date of this ephemeris segment.

### Method Signature
`AbsoluteDate getStart()`
```

--------------------------------

### getValidityStart

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/time/SampledClockModel.html

Gets the start date of the validity period for the clock model.

```APIDOC
## getValidityStart()

### Description
Get validity start.

### Returns
- AbsoluteDate - model validity start
```

--------------------------------

### PropagationStepRecorder.init

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/propagation/class-use/SpacecraftState.html

Initializes the step recorder at the start of a propagation, providing the initial spacecraft state.

```APIDOC
## PropagationStepRecorder.init

### Description
Initialize step handler at the start of a propagation.

### Method Signature
`void init(SpacecraftState s0, AbsoluteDate t)`

### Parameters
* `s0` (SpacecraftState) - The initial state of the spacecraft.
* `t` (AbsoluteDate) - The initial date.
```

--------------------------------

### int getN4()

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/gnss/metric/messages/rtcm/ephemeris/Rtcm1020Data.html

Get the four-year interval number starting from 1996.

```APIDOC
## getN4

### Description
Get the four-year interval number starting from 1996.

### Returns
- **int** - the four-year interval number starting from 1996
```

--------------------------------

### NtripClient.startStreaming

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/index-all.html

Connects to a specified mount point and initiates the streaming of data.

```APIDOC
## Method: startStreaming

### Description
Connects to a mount point and starts streaming data from it.

### Signature
`void startStreaming(String mountPoint, Type type, boolean isBlocking, boolean isReconnect)`

### Parameters
- **mountPoint** (String) - The mount point to connect to.
- **type** (Type) - The type of data stream.
- **isBlocking** (boolean) - Whether the connection should block.
- **isReconnect** (boolean) - Whether to attempt reconnection.
```

--------------------------------

### Get Ephemeris Segment Start Date

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/files/ccsds/ndm/odm/ocm/TrajectoryStateHistory.html

Retrieves the start date of this ephemeris segment. This date is equivalent to calling getPropagator().getMinDate() and is specified by the EphemerisFile.EphemerisSegment interface.

```java
publicAbsoluteDategetStart()
```

--------------------------------

### init Method

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/estimation/measurements/generation/GatheringSubscriber.html

Initializes the subscriber at the start of a measurements generation.

```APIDOC
## init(AbsoluteDate start, AbsoluteDate end)

### Description
Initialize subscriber at the start of a measurements generation. This method is called once at the start of the measurements generation. It may be used by the subscriber to initialize some internal data if needed.

Specified by:
`init` in interface `GeneratedMeasurementSubscriber`

### Parameters
* `start` (AbsoluteDate) - start of the measurements time span
* `end` (AbsoluteDate) - end of the measurements time span

### Method
`public void init(AbsoluteDate start, AbsoluteDate end)`
```

--------------------------------

### setUpStmAndJacobianGenerators Method

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/propagation/integration/AbstractIntegratedPropagator.html

Sets up the handling for State Transition Matrix (STM) and Jacobian matrix computations. This method is relevant for propagators that need to compute these matrices.

```java
protected void setUpStmAndJacobianGenerators()

```

--------------------------------

### NumericalPropagator Setup Example

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/propagation/numerical/NumericalPropagator.html

This code snippet demonstrates a typical setup for Low Earth Orbit propagation using equinoctial parameters and true longitude argument.

```APIDOC
## NumericalPropagator Setup Example

### Description
This code snippet demonstrates a typical setup for Low Earth Orbit propagation using equinoctial parameters and true longitude argument.

### Code
```java
 final double dP       = 0.001;
 final double minStep  = 0.001;
 final double maxStep  = 500;
 final double initStep = 60;
 final double[][] tolerance = ToleranceProvider.getDefaultToleranceProvider(dP).getTolerances(orbit, OrbitType.EQUINOCTIAL);
 AdaptiveStepsizeIntegrator integrator = new DormandPrince853Integrator(minStep, maxStep, tolerance[0], tolerance[1]);
 integrator.setInitialStepSize(initStep);
 propagator = new NumericalPropagator(integrator);
```
```

--------------------------------

### getValidityStart

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/time/AggregatedClockModel.html

Gets the start date of the validity period for this aggregated clock model.

```APIDOC
## getValidityStart()

### Description
Get validity start.

### Specified by:
`getValidityStart` in interface `ClockModel`

### Returns
AbsoluteDate - model validity start
```

--------------------------------

### AccelerationModel Initialization

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/time/class-use/AbsoluteDate.html

Demonstrates the initialization of AccelerationModel using an initial state and a target AbsoluteDate.

```APIDOC
## AccelerationModel.init

### Description
Initialize the acceleration model at the start of the propagation.

### Method Signature
`default void init(SpacecraftState initialState, AbsoluteDate target)`
```

--------------------------------

### Building an OcmWriter

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/files/ccsds/ndm/odm/ocm/class-use/OcmWriter.html

Demonstrates how to obtain an OcmWriter instance using the WriterBuilder.

```APIDOC
## WriterBuilder.buildOcmWriter()

### Description
Build a writer for Orbit Comprehensive Messages.

### Method
`buildOcmWriter()`

### Returns
An instance of `OcmWriter`.
```

--------------------------------

### Get Firing Start Detector

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/forces/maneuvers/trigger/StartStopEventsTrigger.html

Retrieves the detector used for initiating a maneuver.

```java
public
A getStartDetector()
```

--------------------------------

### getCthrthr

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/files/ccsds/ndm/cdm/RTNCovariance.html

Gets the object [9,9] in the covariance matrix. The indices start at 1.

```APIDOC
## getCthrthr

### Description
Gets the object [9,9] in the covariance matrix. The indices start at 1.

### Method
public double getCthrthr()

### Returns
- **double** - The object [9,9] in the covariance matrix (in m²/s⁴).
```

--------------------------------

### Initialize DataProvidersManager

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/data/DataProvidersManager.html

Build an instance of DataProvidersManager with the default configuration.

```java
public DataProvidersManager()
```

--------------------------------

### init (SpacecraftState)

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/forces/radiation/RadiationPressureModel.html

Initializes the force model at the start of propagation using a SpacecraftState.

```APIDOC
## init

### Description
Initialize the force model at the start of propagation. This method will be called before any calls to `ForceModel.addContribution` or `ForceModel.acceleration`.

### Parameters
* `initialState` (SpacecraftState) - spacecraft state at the start of propagation.
* `target` (AbsoluteDate) - date of propagation. Not equal to `initialState.getDate()`.
```

--------------------------------

### getCthrsrp

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/files/ccsds/ndm/cdm/RTNCovariance.html

Gets the object [9,8] in the covariance matrix. The indices start at 1.

```APIDOC
## getCthrsrp

### Description
Gets the object [9,8] in the covariance matrix. The indices start at 1.

### Method
public double getCthrsrp()

### Returns
- **double** - The object [9,8] in the covariance matrix (in m³/(kg.s²)).
```

--------------------------------

### init

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/forces/maneuvers/jacobians/TriggerDate.html

Initialization method called at propagation start. The default implementation does nothing.

```APIDOC
## init

### Description
Initialization method called at propagation start. The default implementation does nothing.

### Parameters
* **initialState** (SpacecraftState) - initial spacecraft state (at the start of propagation).
* **target** (AbsoluteDate) - date of propagation. Not equal to `initialState.getDate()`.
```

--------------------------------

### getCthrdrg

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/files/ccsds/ndm/cdm/RTNCovariance.html

Gets the object [9,7] in the covariance matrix. The indices start at 1.

```APIDOC
## getCthrdrg

### Description
Gets the object [9,7] in the covariance matrix. The indices start at 1.

### Method
public double getCthrdrg()

### Returns
- **double** - The object [9,7] in the covariance matrix (in m³/(kg.s²)).
```

--------------------------------

### getCthrndot

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/files/ccsds/ndm/cdm/RTNCovariance.html

Gets the object [9,6] in the covariance matrix. The indices start at 1.

```APIDOC
## getCthrndot

### Description
Gets the object [9,6] in the covariance matrix. The indices start at 1.

### Method
public double getCthrndot()

### Returns
- **double** - The object [9,6] in the covariance matrix (in m²/s³).
```

--------------------------------

### Solve boundary conditions with initial guess and scales

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/control/indirect/shooting/AbstractFixedInitialCartesianSingleShooting.html

Solve for the boundary conditions, given an initial mass, an initial guess for the adjoint variables, and user-defined scales.

```java
public ShootingBoundaryOutput solve(double initialMass,
                                    double[] initialGuess,
                                    double[] userScales)
```

--------------------------------

### Constructor Summary

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/propagation/analytical/gnss/data/CommonGnssData.html

Summary of constructors for CommonGnssData.

```APIDOC
### Constructor Summary

| Modifier | Constructor | Description |
|---|---|---|
| `protected` | `CommonGnssData(double mu, double angularVelocity, int weeksInCycle, TimeScales timeScales, SatelliteSystem system)` | Constructor. |
| `protected` | `CommonGnssData(FieldCommonGnssData<T, A> original)` | Constructor from field instance. |
```

--------------------------------

### getCthrtdot

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/files/ccsds/ndm/cdm/RTNCovariance.html

Gets the object [9,5] in the covariance matrix. The indices start at 1.

```APIDOC
## getCthrtdot

### Description
Gets the object [9,5] in the covariance matrix. The indices start at 1.

### Method
public double getCthrtdot()

### Returns
- **double** - The object [9,5] in the covariance matrix (in m²/s³).
```

--------------------------------

### formatUtcOffset

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/time/TimeComponents.html

Get the UTC offset as a string in ISO8601 format. For example, '+00:00'.

```APIDOC
## formatUtcOffset

### Description
Get the UTC offset as a string in ISO8601 format. For example, `+00:00`.

### Returns
the UTC offset as a string.

### See Also
`toStringWithoutUtcOffset()`, `toString()`
```

--------------------------------

### Constructor with Full Parameters

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/propagation/analytical/tle/generation/FixedPointTleGenerationAlgorithm.html

Constructor for FixedPointTleGenerationAlgorithm allowing full configuration of epsilon, maxIterations, scale, UTC time scale, and TEME frame.

```java
public FixedPointTleGenerationAlgorithm(double epsilon,
                                        int maxIterations,
                                        double scale,
                                        TimeScale utc,
                                        Frame teme)
```

--------------------------------

### Get File Epoch Start Time

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/files/sinex/AbstractSinex.html

Retrieves the start time of the data epoch within the SINEX file. This marks the beginning of the time interval covered by the data.

```java
public AbsoluteDate getFileEpochStartTime()
```

--------------------------------

### Get Sun - Java

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/bodies/CelestialBodyFactory.html

Retrieve the singleton instance for the Sun.

```java
@DefaultDataContext
public static CelestialBody getSun()

```

--------------------------------

### Station Constructor

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/files/sinex/Station.html

Initializes a new Station object.

```APIDOC
## Station()

### Description
Constructor.

### Method
Constructor

### Endpoint
Station()

### Parameters
None

### Request Example
None

### Response
None
```

--------------------------------

### Get the value of the leap at offset validity start

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/time/UTCTAIOffset.html

Retrieve the TimeOffset value representing the leap second at the start of this offset's validity period. This indicates the magnitude of the leap.

```java
public TimeOffset getLeap()
```

--------------------------------

### Get Minimum Date Method

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/utils/BoundedPVCoordinatesProvider.html

Retrieves the start date of the valid time range.

```java
AbsoluteDate getMinDate()
```

--------------------------------

### IodLaplace Constructor

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/estimation/iod/IodLaplace.html

Constructs an instance of the IodLaplace algorithm.

```APIDOC
## IodLaplace(double mu)

### Description
Constructor.

### Parameters
* **mu** (double) - gravitational constant
```

--------------------------------

### init(FieldSpacecraftState<T> initialState, FieldAbsoluteDate<T> target)

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/propagation/integration/FieldAdditionalDerivativesProvider.html

Initialize the generator at the start of propagation.

```APIDOC
## Method init(FieldSpacecraftState<T> initialState, FieldAbsoluteDate<T> target)

Initialize the generator at the start of propagation.

Parameters:
    `initialState` - initial state information at the start of propagation     `target` - date of propagation
```

--------------------------------

### getSecondsInWeek

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/time/GNSSDate.html

Gets the number of seconds elapsed since the start of the current GNSS week.

```APIDOC
## getSecondsInWeek

### Description
Gets the number of seconds since week start.

### Returns
* `double` - number of seconds since week start

### Since
12.0
```

--------------------------------

### getMilliInWeek

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/time/GNSSDate.html

Gets the number of milliseconds elapsed since the start of the current GNSS week.

```APIDOC
## getMilliInWeek

### Description
Gets the number of milliseconds since week start.

### Returns
* `double` - number of milliseconds since week start
```

--------------------------------

### init(SpacecraftState initialState, AbsoluteDate target)

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/forces/maneuvers/trigger/ManeuverTriggersResetter.html

Initialization method called at propagation start.

```APIDOC
### init(SpacecraftState initialState, AbsoluteDate target)

#### Description
Initialization method called at propagation start. The default implementation does nothing.

#### Parameters
- **initialState** (SpacecraftState) - initial spacecraft state (at the start of propagation).
- **target** (AbsoluteDate) - date of propagation.
```

--------------------------------

### Constructor Summary

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/control/indirect/shooting/AbstractIndirectShooting.html

Lists the constructors available for the AbstractIndirectShooting class.

```APIDOC
### Constructor Summary

Constructors Modifier | Constructor | Description
---|---|---
`protected` | `AbstractIndirectShooting(ShootingPropagationSettings propagationSettings)` | Constructor.
```

--------------------------------

### Get Start Date - OffsetModel

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/time/OffsetModel.html

Retrieves the date when the offset model becomes effective.

```java
public DateComponents getStart()
```

--------------------------------

### Get Validity Period

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/gnss/attitude/GPSBlockIIF.html

Retrieves the start and end dates for the provider's validity.

```java
public AbsoluteDate validityStart()
```

```java
public AbsoluteDate validityEnd()
```

--------------------------------

### AbstractIndirectShooting Integrator Building

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/propagation/class-use/FieldSpacecraftState.html

Illustrates how to build a Field integrator using an initial FieldSpacecraftState.

```APIDOC
## buildFieldIntegrator

### Description
Create Field integrator.

### Method Signature
`protected <T extends CalculusFieldElement<T>> FieldExplicitRungeKuttaIntegrator<T> buildFieldIntegrator(FieldSpacecraftState<T> initialState)`

### Parameters
*   **initialState** (`FieldSpacecraftState<T>`) - The initial state to build the integrator from.
```

--------------------------------

### init(FieldSpacecraftState<T> s0, FieldAbsoluteDate<T> t)

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/forces/maneuvers/FieldImpulseManeuver.html

Initializes the event detector at the start of a propagation.

```APIDOC
### Method
`public void init(FieldSpacecraftState<T> s0, FieldAbsoluteDate<T> t)`

### Description
Initializes the event detector at the start of a propagation. This method is called once at the start of the propagation and may be used to initialize internal data.

### Parameters
- **s0** (FieldSpacecraftState<T>) - Initial state
- **t** (FieldAbsoluteDate<T>) - Target time for the integration
```

--------------------------------

### Time Information

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/files/ccsds/ndm/tdm/TdmMetadata.html

Methods to get and set the start and stop times for the tracking data.

```APIDOC
## getStartTime

### Description
Getter for the startTime.

### Method
```java
public AbsoluteDate getStartTime()
```

### Returns
- AbsoluteDate: the startTime

## setStartTime

### Description
Setter for the startTime.

### Method
```java
public void setStartTime(AbsoluteDate startTime)
```

### Parameters
- **startTime** (AbsoluteDate) - the startTime to set

## getStopTime

### Description
Getter for the stopTime.

### Method
```java
public AbsoluteDate getStopTime()
```

### Returns
- AbsoluteDate: the stopTime

## setStopTime

### Description
Setter for the stopTime.

### Method
```java
public void setStopTime(AbsoluteDate stopTime)
```

### Parameters
- **stopTime** (AbsoluteDate) - the stopTime to set
```

--------------------------------

### AbstractIntegratedPropagator.MainStateEquations.init

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/time/class-use/AbsoluteDate.html

Initializes the state equations at the start of propagation using an initial state and a target date.

```APIDOC
## init

### Description
Initialize the equations at the start of propagation.

### Method Signature
`default void init(SpacecraftState initialState, AbsoluteDate target)`
```

--------------------------------

### Get Ephemeris Segment Bounds

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/files/ccsds/ndm/adm/aem/AemMetadata.html

Retrieves the start and end dates of the ephemeris segment.

```java
public AbsoluteDate getStart()
```

```java
public AbsoluteDate getStop()
```

--------------------------------

### IodLaplace Constructor

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/estimation/iod/IodLaplace.html

Constructor for the IodLaplace class. Initializes the algorithm with the gravitational constant.

```java
public IodLaplace(double mu)
```

--------------------------------

### Getting Velocity

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/time/class-use/AbsoluteDate.html

Examples of retrieving the velocity vector at a specific AbsoluteDate and in a given Frame.

```APIDIDOC
## getVelocity

### Description
Get the velocity of the body in the selected frame at a specific date.

### Method Signature
`Vector3D getVelocity(AbsoluteDate date, Frame frame)`

### Parameters
- `date` (AbsoluteDate) - The date at which to retrieve the velocity.
- `frame` (Frame) - The frame in which to express the velocity.

### Usage Examples
- `ConstantPVCoordinatesProvider.getVelocity(date, frame)`
- `ExtendedPositionProvider.getVelocity(date, frame)`
- `PVCoordinatesProvider.getVelocity(date, frame)`
```

--------------------------------

### Screening Period Management

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/files/ccsds/ndm/cdm/CdmRelativeMetadata.html

Methods for getting and setting the start and stop times of the screening period.

```APIDOC
## getStartScreenPeriod()

### Description
Get the start time in UTC of the screening period for the conjunction assessment.

### Method
public AbsoluteDate getStartScreenPeriod()

### Parameters
None

### Returns
start time in UTC of the screening period
```

```APIDOC
## setStartScreenPeriod(AbsoluteDate startScreenPeriod)

### Description
Set the start time in UTC of the screening period for the conjunction assessment.

### Method
public void setStartScreenPeriod(AbsoluteDate startScreenPeriod)

### Parameters
- **startScreenPeriod** (AbsoluteDate) - start time in UTC of the screening period to be set
```

```APIDOC
## getStopScreenPeriod()

### Description
Get the stop time in UTC of the screening period for the conjunction assessment.

### Method
public AbsoluteDate getStopScreenPeriod()

### Parameters
None

### Returns
stop time in UTC of the screening period
```

--------------------------------

### CIPM2007 Constructor

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/models/earth/weather/water/CIPM2007.html

Initializes the CIPM2007 water vapor pressure model.

```APIDOC
## CIPM2007()

### Description
Initializes the CIPM2007 water vapor pressure model.

### Method
Constructor

### Parameters
None
```

--------------------------------

### Initialize Propagation

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/forces/maneuvers/FieldImpulseProvider.html

Method called at the start of propagation. It allows for any necessary setup before maneuvers are applied.

```java
default void init(FieldSpacecraftState<T> initialState,
                  FieldAbsoluteDate<T> targetDate)
```

--------------------------------

### init(SpacecraftState s0, AbsoluteDate t, double step)

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/files/ccsds/ndm/odm/oem/StreamingOemWriter.SegmentWriter.html

Initializes the step handler at the start of a propagation.

```APIDOC
### Method
`public void init(SpacecraftState s0, AbsoluteDate t, double step)`

Initializes the step handler. This method is called once at the start of propagation and handles automatic header writing and metadata time setting.

#### Parameters
- **s0** (SpacecraftState) - Initial state
- **t** (AbsoluteDate) - Target time for the integration
- **step** (double) - The duration in seconds of the fixed step
```

--------------------------------

### RadiationPressureModel.init

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/time/class-use/FieldAbsoluteDate.html

Initializes the radiation pressure model at the start of propagation, using FieldAbsoluteDate.

```APIDOC
## RadiationPressureModel.init

### Description
Initialize the force model at the start of propagation.

### Method Signature
`<T extends CalculusFieldElement<T>> void init(FieldSpacecraftState<T> initialState, FieldAbsoluteDate<T> target)`
```

--------------------------------

### Get Initial State - Java

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/propagation/Propagator.html

Retrieves the initial state of the propagator. This is the starting point from which propagation begins.

```java
SpacecraftState getInitialState()
```

--------------------------------

### SoftwareConfiguration Constructor

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/files/ilrs/CRDConfiguration.SoftwareConfiguration.html

Initializes a new instance of the SoftwareConfiguration class.

```APIDOC
## SoftwareConfiguration()

### Description
Empty constructor.

### Constructor
`SoftwareConfiguration()`
```

--------------------------------

### Managing Time Bounds

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/files/ccsds/ndm/adm/acm/AcmMetadata.html

Methods to get and set the start and stop times for the data contained in the OCM.

```java
public AbsoluteDate getStartTime()
```

```java
public void setStartTime(AbsoluteDate startTime)
```

```java
public AbsoluteDate getStopTime()
```

```java
public void setStopTime(AbsoluteDate stopTime)
```

--------------------------------

### getSplitSecondsInWeek

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/time/GNSSDate.html

Gets the number of seconds elapsed since the start of the current GNSS week, returned as a TimeOffset object.

```APIDOC
## getSplitSecondsInWeek

### Description
Gets the number of seconds since week start.

### Returns
* `TimeOffset` - number of seconds since week start

### Since
13.0
```

--------------------------------

### init (FieldSpacecraftState)

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/forces/radiation/ConicallyShadowedLightFluxModel.html

Initializes the model with the initial field spacecraft state and target date before propagation.

```APIDOC
## init

### Description
Perform initialization steps before starting propagation.

### Type Parameters
* `T` - field type

### Parameters
* `initialState` (FieldSpacecraftState<T>) - initial state
* `targetDate` (FieldAbsoluteDate<T>) - target date for propagation
```

--------------------------------

### Constructor for AbstractFixedInitialCartesianSingleShooting

Source: https://www.orekit.org/site-orekit-13.1.4/apidocs/org/orekit/control/indirect/shooting/AbstractFixedInitialCartesianSingleShooting.html

Constructor with boundary conditions as orbits. Requires propagation settings and a template for the initial spacecraft state.

```java
protected AbstractFixedInitialCartesianSingleShooting(ShootingPropagationSettings propagationSettings,
                                                      SpacecraftState initialSpacecraftStateTemplate)
```
Tokens:
Raw