Depends on what factor you want to be perfectly/better determined. If you want full automation but don't need perfection on the route taken or the location of each photo, follow the procedure above.
A different way, that isn't perfectly automated but performs a precise circular path, is to create an orbit, and set the orbit speed at something easily calculated. If you set it for 3 degrees/second, for example, you know you need to snap a photo every 15 seconds. You can set the orbit in motion with the app, then simply count (or use a stopwatch for better precision) while it's in motion around the circle, and press the photo button every 15 seconds.