Ken, I have already implemented the concept of ground station, albeit, i'm not sure I like the way I have the configuration file set up, see:
ground station implementation: Google Earth Satellite Tracker - Ground Stations U... los implementation: Google Earth Satellite Tracker - Line of Sight Upd... I'm likely going to implement 1 and move on for now. With respects to the ground station, I like the idea of having a minimum elevation angle, that would be insanely easy to implement. Expect these two to be implemented later tonight :-) Joseph Armbruster On Mar 25, 2013, at 6:42 PM, Ken Ernandes wrote: > My humble suggestion: > > 1. Implement option 1 for the satellite footprint. > 2. If you decide to give the users the ability to input their location, them > the option to provide either a single minimum elevation angle or a local map > -- i.e., 360 individual minimum elevations as a function of Azimuth. It's > much easier to project this and the user is generally interested in an > unobstructed LOS with respect to his/her location. > > 73, Ken N2WWD > > Sent from my iPad > > > > On Mar 25, 2013, at 11:15 AM, Joseph Armbruster <[email protected]> > wrote: > >> >> I can not decide how to implement ground footprints with my google earth >> satellite tracker. I figured, since I can't make up my mind, I should get a >> second (and third, and fourth) opinion. For this thread, I would like to >> discuss how satellite ground-footprints should be implemented. A quick >> brainstorm led me to three possible implementations (I am leaning towards >> 3). For each of these, I assume that a geographic line-of-sight footprint >> is desired with no RF characteristics taken into consideration: >> >> option 1 : assume a spherical earth model and project a polygon downwards >> towards the footprint >> >> - note: this is obviously the easiest approach but will result in the most >> error >> >> option 2 : assume an ellipsoidal earth model and project an irregularly >> shaped polygon downwards towards the footprint >> >> - note: this is arguably more difficult than option 1 and would result in >> less error >> >> option 3 : use a digital elevation model and an ellipsoidal model to >> cull-out regions that are not visible due to geographic features and project >> an irregularly shaped polygon downwards towards the footprint >> >> - note: In this case, our footprint polygon would have holes cut out for the >> regions that are culled out by mountain ranges, canyons / etc... Obviously, >> this would be the most difficult to implement but would likely be the best >> visual representation. The problem is, I would never dream of distributing >> DEMs for the entire Earth with my tool, even DTED0 would be absurd in my >> opinion. I could make the elevation queries accessible using a web-service, >> but then the user would be tied to the internet. The other option would be >> to allow the users to download their elevation data into a cache, then the >> tool would just load / use it. This way the user would only have to obtain >> the elevation data for their region of interest. Maybe that would be the >> best approach? I am open to suggestions! >> >> If you have any experience visualizing footprints, please let me know. I >> would be interested in hearing your lessons-learned. These are what the >> line-of-sight indicators look like right now: Google Earth Satellite >> Tracker - Line of Sight Update >> >> I am open to comments and suggestions, >> Joseph Armbruster >> _______________________________________________ >> Sent via [email protected]. Opinions expressed are those of the author. >> Not an AMSAT-NA member? Join now to support the amateur satellite program! >> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
