Hey Nicholas, I appreciate the input. I added RAIM and WAAS to the Aircraft Flight Instruments and Navigation Equipment lesson (II.A.) and included information on GPS Substitution and a small blurb on LAAS as well.
If you (or anyone else) ever come across something you feel is missing from the lessons send an email to firstname.lastname@example.org
and I'll get the corrections made. And since you have immediate access to all the updates, the updated lessons are yours free!