scenarioBasicOrbitStream

Overview

This script duplicates the basic orbit simulation in the scenario scenarioBasicOrbit. The difference is that this version allows for the Basilisk simulation data to be live streamed to the About Vizard visualization program, with optional 2-way communication with Vizard (live user inputs to the simulation).

The script is found in the folder basilisk/examples and executed by using:

python3 scenarioBasicOrbitStream.py

To enable live data streaming and/or broadcast streaming, the enableUnityVisualization() method is provided with liveStream and broadcastStream argument using:

vizSupport.enableUnityVisualization(scSim, simTaskName, scObject
                                    , liveStream=True
                                    , broadcastStream=True)

When starting Basilisk simulation it prints now to the terminal that it is trying to connect to Vizard:

Waiting for Vizard at tcp://localhost:5556

Copy tcp://localhost:5556 and open the Vizard application. Enter this address in the connection field and select “Direct Communication” mode as well as “Live Streaming”. After this the Basilisk simulation resumes and will live stream the data to Vizard.

Vizard Direct Communication Panel Illustration

To avoid the simulation running too quickly, this tutorial example script includes the clock_sync module that enables a 50x realtime mode using:

clockSync = clock_synch.ClockSynch()
clockSync.accelFactor = 50.0
scSim.AddModelToTask(simTaskName, clockSync)

This way a 10s simulation time step will take 0.2 seconds with the 50x speed up factor.

scenarioBasicOrbitStream.run(show_plots, liveStream, broadcastStream, timeStep, orbitCase, useSphericalHarmonics, planetCase)

At the end of the python script you can specify the following example parameters.

Parameters:

• show_plots (bool) – Determines if the script should display plots

• liveStream (bool) – Determines if the script should use live data streaming

• broadcastStream (bool) – Determines if the script should broadcast messages for listener Vizards to pick up.

• timeStep (double) – Integration update time in seconds

• orbitCase (str) –

  String	Definition
  ’LEO’	Low Earth Orbit
  ’GEO’	Geosynchronous Orbit
  ’GTO’	Geostationary Transfer Orbit

• useSphericalHarmonics (Bool) – False to use first order gravity approximation: \(\frac{GMm}{r^2}\)

• planetCase (str) – {‘Earth’, ‘Mars’}