That would be a DIY by GPS would it not? -
Riding a DIY permanent by GPS - as you're creating the course.
A GPS perm would be more along the lines of:
Look through list of routes online and pick one
Click online entry and paypal buttons
Recieve route sheet and track file
Fiddle track file onto gps unit for navigation, OR just follow the route sheet with gps unit just for tracking
Have a lovely relaxing bike ride following a route vouchsafed by someone who's put a lot of effort into it.
Get home, have cup of tea
Plug in GPS unit, email/upload your track file from the unit
Org checks that GPS track confirms you passed through points x,y,z,a,b, possibly checking that you only went between a+b via BIG HILL if needed and all within the time limit
If it all checks out, you get the points/warm fuzzies from completing the ride within the rules.