Plane: add flag to disable wp speed scaling on heading and groundtrack

ArduPlane/quadplane.cpp

@@ -538,6 +538,13 @@ const AP_Param::GroupInfo QuadPlane::var_info2[] = {
     // @User: Standard
     AP_GROUPINFO("BCK_PIT_LIM", 38, QuadPlane, q_bck_pitch_lim, 10.0f),
 
+    // @Param: WP_SPD_SCALE
+    // @DisplayName: Do waypoint speed scaling based on heading and groundtrack
+    // @Description: This flag can be used to disable the waypoint speed scaling based on heading and ground track difference. When landing on a moving platform it is possible to have a prevailing headwind that is not in the direction of the groundspeed vector.
+    // @Values: 0 1
+    // @User: Advanced
+    AP_GROUPINFO("WP_SPD_SCALE", 39, QuadPlane, q_do_wp_speed_scaling, 1),
+
     AP_GROUPEND
 };
 
@@ -3009,7 +3016,7 @@ float QuadPlane::get_scaled_wp_speed(float target_bearing_deg) const
 {
     const float yaw_difference = fabsf(wrap_180(degrees(plane.ahrs.get_yaw()) - target_bearing_deg));
     const float wp_speed = wp_nav->get_default_speed_xy() * 0.01;
-    if (yaw_difference > 20) {
+    if (q_do_wp_speed_scaling == 1 && yaw_difference > 20) {
         // this gives a factor of 2x reduction in max speed when
         // off by 90 degrees, and 3x when off by 180 degrees
         const float speed_reduction = linear_interpolate(1, 3,

ArduPlane/quadplane.h

@@ -429,6 +429,9 @@ class QuadPlane
     float q_bck_pitch_lim_cd; // backward pitch limit applied when using Q_BCK_PIT_LIM
     uint32_t q_pitch_limit_update_ms; // last time the backward pitch limit was updated
 
+    // flag to disable the use of wp speed scaling on heading and groundtrack difference
+    uint32_t q_do_wp_speed_scaling;
+
     // when did we last run the attitude controller?
     uint32_t last_att_control_ms;