Dean Goedde has added a cool feature to the forthcoming AttoPilot: relative waypoints. He explains:
"I have innovated a new method for using waypoint paths: a method to signify a waypoint list as being a "template". In this method, the waypoint list becomes a list of relative coordinates, relative to the 0th WP in the list as an "anchor" that is translated to the actual coordinates of where you happen to boot up the system and get first GPS lock. This way, you have a template type WP file on the SD card of up to 100 WPs, perhaps specifying a 1x1 mile grid with 200 meters between the tracks. You also have an extensive set of triggers defined in this WP template, as to snap a photo every 200 meters along the straight tracks. You boot up in the bush somewhere, fly the path, pack up and move 2 miles away and repeat, ad infinitum. An entire day of Geo mapping with no laptop at the field, and TONS of detailed LOG data for exact location and position of the plane during each photo. The math for converting the relative coordinates takes full care of the actual latitude and how to compress/decompress the longitudes from real-->relative-->real coordinates... path is precisely the same either on the equator or at 85 degrees North."
We've been thinking about a similar approach for a supercheap UAV for kids that would just fly selectable patterns around its launch position: figure 8s, squares, circles, etc. No programming required, and potentially no FAA issues since the waypoints are not programmable. Our unofficial motto: "Turning the military-industrial complex into a toy" ;-)
Interestingly, Dean has also created a "synthetic" NMEA GPS sentence for telemetry data, which is just what Jordi did with his GSP parser. Jordi's was called the "$JORDI", Dean's is called "$ATTO".