Chapter 2: Autopilot
ParaDrone is designed to autonomously fly and land at a designated landing zone. It will
attempt to fly a standard landing pattern including downwind, base, and final legs.
Landing zone is set using the android app. Click settings ⚙, and then “Set LZ”. Drag the map to
be centered on the intended landing zone, and rotate the map to align the arrow with the landing
direction (into the wind). The app will attempt to fetch ground elevation from the internet, but can
be set manually if needed, or if internet access is not available.
Autopilot will not make any turns below 30m. It will begin flaring to land at 6m above ground
level.
If GPS signal is lost for 60 seconds, ParaDrone will enter a slow right-hand spiral. This is to
keep it from flying far away from the LZ in case of lost signal.
Planner
The planner uses waypoints and dubins paths to approximate paraglider flight paths. It can be in
one of several modes, depending on location, landing zone, and user input. Modes include:
● Idle - toggles to neutral position
● RC - remote control override (lasts for 10 seconds from last control input)
● Auto - autopilot engaged but no plan
● Str - straight ahead
● NaiveL, NaiveR - naive path plan (left or right turn)
● DubinL, DubinR - dubins path plan (left or right turn)
● Waypoint - downwind, base, final waypoint plan
● Final - final approach, toggles up (30m AGL)
● Flare - toggles down! (6m AGL)
The flight planner is designed to achieve several goals. First it should be able to run on low
power microcontrollers. It should fly a pattern similar to a human skydiver. If there is adequate
altitude, the autopilot will set up near the landing zone, and then fly a left or right hand pattern to
land in the indicated direction. At a predetermined altitude of 30m AGL there will be no more
turns and toggles return to full flight position. At 6m AGL it will begin to flare for landing.
