scenarioVizPoint

../../_images/Vizard1.jpg

Illustration of Vizard showing a custom spacecraft camera view.

Overview

This scenario demonstrates how instantiate a visualization interface. This includes setting camera parameters and capture rates. This stems for an attitude detumble scenario, but focuses on pointing towards a celestial body in order to display the visualization Vizard, and show the camera capabilities.

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

python3 scenarioVizPoint.py

When the simulation completes 3 plots are shown for the MRP attitude history, the rate tracking errors, as well as the control torque vector. The run() method is setup to write out the Vizard data file to sub-folder _VizFiles/scenarioVizPoint_UnityViz.bin. By running Vizard and playing back this data file you will see the custom camera view that is created as illustrated in the Vizard snapshot above.

The simulation layout is identical the the scenarioAttitudeFeedback scenario when it comes to FSW modules The spacecraft starts in a tumble and controls it’s rate as well as points to the Earth.

Two mission scenarios can be simulated. The first one mimics the DSCOVR mission spacecraft and its EPIC camera pointing towards Earth. The second simulates a spacecraft orbiting about Mars. The attitude results are the same as the attitude feedback scenario, and pictured in the following plots. The differences lies in where they are pointing.

../../_images/scenarioVizPoint1.svg../../_images/scenarioVizPoint2.svg../../_images/scenarioVizPoint3.svg

In each case a spacecraft fixed camera is simulated. This is done by creating a camera configuration message called camera_config_data. The vizInterface module searches for a message with this name by default. If it exists, the camera information is read in and sent across to Vizard to render out that camera view point image. If the camera message should be written to another message name, then the vizInterface parameter cameraConfInMsgName can be set to this new name.

DSCOVR Mission Setup

The first setup has the spacecraft pointing to Earth, from a distant, L1 vantage point. The scenario controls the spacecraft attitude to Earth pointing mode, and snaps pictures at a defined rate. This camera parameters are taken from NASA’s EPIC camera website on the date 2018 OCT 23 04:35:25.000 (UTC time). In this setup the pointing needs to be set to Earth, given it’s position.

Mars Orbit Setup

The second control scenario points the spacecraft towards Mars on a Mars orbit.

scenarioVizPoint.run(show_plots, missionType, saveVizardFile)[source]

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

  • missionType (str) –

    String

    Definition

    ’dscovr’

    Simulates the NASA DSCOVR mission

    ’marsOrbit’

    Simulates an orbit about Mars

  • saveVizardFile (bool) – Flag to save off the Vizard data file