globe-orbit-plot

MATLAB Scripts to plot LEO constellations, both in 2D (as ground tracks or SSPs) and in 3D as an interactive map that shows the orbits.

Usage:

Set the constellation satellites via a .csv file, one for each line, grouped by planes: if you have N planes with M satellites, the M satellites from the first plane should come first, then the M satellites for the second plane, and so on until the Nth plane.

CSV's columns are as follows:

time	a (sem-maj axis)	ecc	inc	RAAN	ω	vo

Where time is the Greenwich Hour angle, a is in meters, vo is the true anomaly, and all angles are in degrees. E.G.:

constellation.csv

36.406,6978135,0,98,0,0,0
36.406,6978135,0,98,0,0,45
36.406,6978135,0,98,0,0,90
36.406,6978135,0,98,0,0,135
36.406,6978135,0,98,0,0,180
36.406,6978135,0,98,0,0,225
[...]

Modify the following lines in the orbit_plotter.m script, and then run the block:

% Read CSV file containing the constellation parameters
con = csvread('PATH/TO/CONSTELLATION/CSV'); % <--- Path to .csv file

% Set the number of planes and sats per plane
nPlanes = 8;        % < ----- N. of planes
nSatsInPlane = 8;   % < ----- N. of sats

Finally, run the script, or the block of code that suits your needs:

• Plot ground tracks in 2D: Plots ground tracks
• Plot in 3D globe: Plots into a user-interactive 3D plot. Other types of basemaps are supported¹ besides the provided default: darkwater.
• Export globe-3D current view as file: Exports the current view of the UI 3D plot to a path/file.pdf indicated in the argument of this function²:

% Export globe-3D current view as file
exportapp(uif,'PATH/TO/OUTPUT/PDF');

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Snapshots

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Requirements and restrictions

Matlab 2020a or later is required to obtain the 3D plots.

The functions used do not appear to be intended to plot orbits, rather to be used in plotting lines, great circles, and regions over the surface of the Earth. To achieve the shown results, great circles are interpolated between sub-satellite points, which are then elevated to the plane's approximate height over the surface of the Earth, based on the orbit's Semi-Major axis and Earth's equatorial radius. Small constellations or trailing satellite formations could yield strange results in the visualizations.

No orbit propagation is performed in this tool, this is yet to be implemented and will allow for more freedom in what can be plotted, mainly in the field of non-symmetric constellations.

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Disclaimer

This is a visualization only tool. These scripts are not intended to be used as a propagator, obtain access intervals, or to obtain any estimation in any way about the behaviour and/or operation of a satellite constellation. No metrics should be obtained using this tool.

Footnotes

1. Many of them require internet connection. ↩

2. Only pdf output is supported. ↩