http://eedesigner.blogspot.com
Python was useful for scripting the calculations and printing a result. This led to Google Maps API, because it just seemed cool to map it out. This led to hosting it on Google App Engine. It's a work in progress as I fine-tune the user interface.
The locations can be validated by checking with this site:
http://www.nstb.tc.faa.gov/RT_WaasSatelliteStatus.htm
This site has taken a step back as I have upgraded from the legacy App Engine. Lots of changes in the API. Some improvements would be again allowing a user to log on and save their location, and clicking on the map to set location.