SITL: Add SIM_WIND_DIR_Z parameter for SITL

This controls the vertical pitch of the 3d wind vector, allowing futher control of the wind
using systems like dronekit. This change directly effects the calcuation of the wind vector

libraries/SITL/SIM_Aircraft.cpp

@@ -565,7 +565,9 @@ void Aircraft::update_dynamics(const Vector3f &rot_accel)
 void Aircraft::update_wind(const struct sitl_input &input)
 {
     // wind vector in earth frame
-    wind_ef = Vector3f(cosf(radians(input.wind.direction)), sinf(radians(input.wind.direction)), 0) * input.wind.speed;
+    wind_ef = Vector3f(cosf(radians(input.wind.direction))*cosf(radians(input.wind.dir_z)), 
+                       sinf(radians(input.wind.direction))*cosf(radians(input.wind.dir_z)), 
+                       sinf(radians(input.wind.dir_z))) * input.wind.speed;
 
     const float wind_turb = input.wind.turbulence * 10.0f;  // scale input.wind.turbulence to match standard deviation when using iir_coef=0.98
     const float iir_coef = 0.98f;  // filtering high frequencies from turbulence

libraries/SITL/SIM_Aircraft.h

@@ -45,6 +45,7 @@ public:
             float speed;      // m/s
             float direction;  // degrees 0..360
             float turbulence;
+            float dir_z;	  //degrees -90..90 
         } wind;
     };
 

libraries/SITL/SITL.cpp

@@ -108,6 +108,7 @@ const AP_Param::GroupInfo SITL::var_info2[] = {
     AP_GROUPINFO("ARSPD_PITOT",  7, SITL,  arspd_fail_pitot_pressure, 0),
     AP_GROUPINFO("GPS_ALT_OFS",  8, SITL,  gps_alt_offset, 0),
     AP_GROUPINFO("ARSPD_SIGN",   9, SITL,  arspd_signflip, 0),
+    AP_GROUPINFO("WIND_DIR_Z",  10, SITL,  wind_dir_z,     0),
     AP_GROUPEND
 };
     

libraries/SITL/SITL.h

@@ -128,10 +128,12 @@ public:
     // wind control
     float wind_speed_active;
     float wind_direction_active;
+    float wind_dir_z_active;
     AP_Float wind_speed;
     AP_Float wind_direction;
     AP_Float wind_turbulance;
     AP_Float gps_drift_alt;
+    AP_Float wind_dir_z;
 
     AP_Int16  baro_delay; // barometer data delay in ms
     AP_Int16  mag_delay; // magnetometer data delay in ms