User Manual 3.3 Multi events detection

User Manual 3.3 Multi events detection

Introduction

Scope

Here are presented all the multi events detectors that could be used in multi propagation.

Javadoc

Those event detectors are available in the packages :

Library	Javadoc
Orekit	Package org.orekit.propagation.event
Patrius	Package fr.cnes.sirius.patrius.events

Links

See :

• [ORB_MPRO_Home Multi propagation chapter]
• [MIS_EVT_Home Events detection introduction chapter]

Useful Documents

None as of now.

Package Overview

None as of now.

Features Description

Multi events detectors

The following events detectors could be used in mono and multi spacecraft propagation :

• ThreeBodiesAngleDetector
• ExtremaThreeBodiesAngleDetector
• SatToSatMutualVisibilityDetector

These three detectors extends AbstractDetector and implements MultiEventDetector.

Using multi numerical propagator, all states concerned by the detection are recovered from the global state vector. Using one of the mono propagator (analytical or numerical), the main state is recovered from the propagation. The others states concerned by the detection are recovered from a PVCoordinatesProvider.

The meaning of the g switching function for the concerned event detectors, and their particularities are presented in dedicated chapter :

• [MIS_ORB_Home Orbit determination events chapter ]for ThreeBodiesAngleDetector and ExtremaThreeBodiesAngleDetector
• [MIS_STASAT_Home Ground stations and satellites events] for SatToSatMutualVisibilityDetector

Getting Started

None as of now.

Contents

Interfaces

|=Interface|=Summary|=Javadoc | EventDetector|This interface represents an event finder.|EventDetector | MultiEventDetector|This interface represents an event finder in multi propagation case.|MultiEventDetector

Classes

|=Classe|=Summary|=Javadoc | ThreeBodiesAngleDetector|This class handles events representing the reaching of a predetermined angle between three bodies.|ThreeBodiesAngleDetector | ExtremaThreeBodiesAngleDetector|This class handles events representing the reaching of of extrema for the angle between three bodies.|ExtremaThreeBodiesAngleDetector | SatToSatMutualVisibilityDetector|This class handles events representing the mutual visibility between two spacecraft's sensors.|SatToSatMutualVisibilityDetector

Using multi events detectors

In multi numerical propagation case, the states concerned by the detection are identified with their ID. Specific constructors should be used in multi numerical propagation case. These constructors take as parameter the ID of states concerned by the detection.

Here after is presented the instanciation of a SatToSatMutualVisibilityDetectorin multi propagation case :

// Initialize multi numerical propagator
final FirstOrderIntegrator integratorMultiSat = new DormandPrince853Integrator(.1, 60, 1e-9, 1e-9);
MultiNumericalPropagator mainPropagator = new MultiNumericalPropagator(integratorMultiSat);
mainPropagator.addInitialState(mainState, STATE1);
mainPropagator.addInitialState(secondaryState, STATE2);
mainPropagator.setAttitudeProvider(attitudeProv, STATE1);
mainPropagator.setAttitudeProvider(attitudeProv, STATE2);
 
// Create SatToSatMultualVisibilityDetector
final MultiEventDetector detector = new SatToSatMutualVisibilityDetector(STATE1, STATE2, mainSpacecraftSensorModel1, secondarySpacecraftSensorModel2, false, 0.01, 10.e-10);
 
// Add detector
mainPropagator.addEventDetector(detector1);
 
// propagate
Map<String, SpacecraftState> endStates = mainPropagator.propagate(date.shiftedBy(duration));

If a wrong constructor is used, i.e a constructor for mono propagation, an exception will be raised during propagation.