Adding GPS for autonomous flight

Another way to introduce autonomy to your quadcopter is to use the GPS capability you learned in Chapter 7, Using GPS for Navigation, to give direction to your sailboat; to control your quadcopter autonomously. You can use the GPS to plan new waypoints and path planning to fly your quadcopter to specific locations. You can use the altitude from the GPS to control the height of your flight, although this might result in some rough landings as it rarely gives the kind of resolution to bring your quadcopter down softly. I often use a sonar sensor, similar to the one covered in Chapter 3, Adding Sensors to Your Tracked Vehicle, to sense the ground and land the quadcopter softly.