Copter: WPNav consolidate acceleration #defines

libraries/AC_WPNav/AC_WPNav.cpp

@@ -380,7 +380,7 @@ void AC_WPNav::advance_target_along_track(float dt)
     }else{
         // increase intermediate target point's velocity if not yet at target speed (we will limit it below)
         if(dt > 0 && _limited_speed_xy_cms < _wp_speed_cms) {
-            _limited_speed_xy_cms += WPNAV_WP_ACCELERATION * dt;
+            _limited_speed_xy_cms += 2.0f * WPNAV_ACCELERATION * dt;
         }
         // do not go over top speed
         if(_limited_speed_xy_cms > _wp_speed_cms) {

libraries/AC_WPNav/AC_WPNav.h

@@ -31,8 +31,6 @@
 #define WPNAV_ALT_HOLD_P                2.0f        // hard coded estimate of throttle controller's altitude hold's P gain.  To-Do: retrieve gain from throttle controller
 #define WPNAV_ALT_HOLD_ACCEL_MAX        250.0f      // hard coded estimate of throttle controller's maximum acceleration in cm/s.  To-Do: retrieve from throttle controller
 
-#define WPNAV_WP_ACCELERATION           500.0f      // acceleration in cm/s/s used to increase the speed of the intermediate point up to it's maximum speed held in _speed_xy_cms
-
 #define WPNAV_MIN_LEASH_LENGTH          100.0f      // minimum leash lengths in cm
 
 class AC_WPNav