Rover: add loiter radius parameter

APMrover2/Parameters.cpp

@@ -599,6 +599,15 @@ const AP_Param::GroupInfo ParametersG2::var_info[] = {
     // @RebootRequired: True
     AP_GROUPINFO("SIMPLE_TYPE", 29, ParametersG2, simple_type, 0),
 
+    // @Param: LOIT_RADIUS
+    // @DisplayName: Loiter radius
+    // @Description: Vehicle will drift when within this distance of the target position
+    // @Units: m
+    // @Range: 0 20
+    // @Increment: 1
+    // @User: Standard
+    AP_GROUPINFO("LOIT_RADIUS", 30, ParametersG2, loit_radius, 2),
+
     AP_GROUPEND
 };
 

APMrover2/Parameters.h

@@ -361,6 +361,7 @@ public:
 
     // loiter type
     AP_Int8 loit_type;
+    AP_Float loit_radius;
 
     // Sprayer
     AC_Sprayer sprayer;

APMrover2/mode_loiter.cpp

@@ -24,13 +24,13 @@ void ModeLoiter::update()
     _distance_to_destination = get_distance(rover.current_loc, _destination);
 
     // if within waypoint radius slew desired speed towards zero and use existing desired heading
-    if (_distance_to_destination <= g.waypoint_radius) {
+    if (_distance_to_destination <= g2.loit_radius) {
         _desired_speed = attitude_control.get_desired_speed_accel_limited(0.0f, rover.G_Dt);
         _yaw_error_cd = 0.0f;
     } else {
         // P controller with hard-coded gain to convert distance to desired speed
         // To-Do: make gain configurable or calculate from attitude controller's maximum accelearation
-        _desired_speed = MIN((_distance_to_destination - g.waypoint_radius) * 0.5f, g.speed_cruise);
+        _desired_speed = MIN((_distance_to_destination - g2.loit_radius) * 0.5f, g.speed_cruise);
 
         // calculate bearing to destination
         _desired_yaw_cd = get_bearing_cd(rover.current_loc, _destination);