Satellite ground track footprint

[spencerdutton]

Has anyone done or is interested in making an add on that allows the footprint cone of a satellite to be displayed.

For those who dont know what Im talking about. The coverage circle or footprint is the area on the Earth from where the satellite is visible. However I would be interested allowing this area to be configurable.

I would be interested in any feed back.

[carlopacca]

A possible solution could be to create a 3D surface as an intersection of a sphere (the planet) and a cone (vertix on the satellite, aperture angle = antenna visibility angle, centered on the vertical of the satellite) and to overlap this 3D area to the planet.

Questions:

1) Is it possible to create such 3D object in an SSC file ?

2) How to manage satellites with variable height ?

Please suggestions

[JackHiggins]

While it is possible, it wouldn't render properly with current celestia versions, becuause objects are showed either completely in front or completely behind other objects. It would probably flicker on & off, or look really weird... The model would be easy to make but just wouldn't show properly...

[carlopacca]

I easily implemented the footprint center, just creating a new object replicating the satellite orbital parameter and only changing the RADIUS defining it equal to PLANET RADIUS + 5km (just for showing it OVER the planet surface).

To implement the footprint extension it could be 2 solutions:

1) creating a CIRCLE.3DS model with the circumference visible (coloured) and a transparent surface: who knows how to create it ?

2) creating a second object circularly orbitating in a ortogonal plane respect to the surface of the planet and using the CELESTIA ORBIT PATH (in red) to show it: who knows how to define these new orbital parameters in SCC files ?

[marc]

Could some code similar to that used to render eclipses do it?

[carlopacca]

The problematic is similar, but I'm not in deep in CELESTIA source code, could you (or someone else) help ?

If not if you can provide me some hints how has been implemented the eclipse module, I can try some attempts

[carlopacca]

The problem in considering the footprint similarly to the eclipse mechanism, imply to add a new light (in OpenGL terms) in CELESTIA, mounted on the satellite and with the light-beam-angle equal to the satellite footprint angle: is it easy or not on CELESTIA source code ?