set takeoff altitude

Initialize takeoff altitude at DEFAULT_OVERRIDE_ALTITUDE meters above ground.

mavsdk_wrapper.cpp

@@ -37,6 +37,7 @@ static auto prom = std::promise<std::shared_ptr<System>>{};
 static std::future<std::shared_ptr<System>> fut;
 
 static const float DEFAULT_RADIUS = 100;
+static const float DEFAULT_OVERRIDE_ALTITUDE = 30;
 static const float EARTH_RADIUS = 6371000;
 static const float ADDED_DISTANCE = (2 * DEFAULT_RADIUS) / EARTH_RADIUS;
 static const double COS_ADDED_DISTANCE = cos(ADDED_DISTANCE);
@@ -341,6 +342,7 @@ int arm(void) {
 }
 
 int takeOff(void) {
+    action->set_takeoff_altitude(DEFAULT_OVERRIDE_ALTITUDE);
     if (doAction(&Action::takeoff, "Takeoff failed"))
         return -1;