AP_GPS: ensure all GPS drivers give headings as 0..360 degrees

this prevents inconsistency between interfaces, and fixes a MAVLink
reporting bug with UAVCAN GPS

libraries/AP_GPS/AP_GPS.cpp

@@ -454,7 +454,7 @@ AP_GPS::setHIL(uint8_t instance, GPS_Status _status, uint64_t time_epoch_ms,
     istate.location.options = 0;
     istate.velocity = _velocity;
     istate.ground_speed = pythagorous2(istate.velocity.x, istate.velocity.y);
-    istate.ground_course_cd = degrees(atan2f(istate.velocity.y, istate.velocity.x)) * 100UL;
+    istate.ground_course_cd = wrap_360_cd(degrees(atan2f(istate.velocity.y, istate.velocity.x)) * 100UL);
     istate.hdop = hdop;
     istate.num_sats = _num_sats;
     istate.have_vertical_velocity |= _have_vertical_velocity;

libraries/AP_GPS/AP_GPS_MTK.cpp

@@ -147,7 +147,7 @@ restart:
             state.location.lng  = swap_int32(_buffer.msg.longitude) * 10;
             state.location.alt  = swap_int32(_buffer.msg.altitude);
             state.ground_speed      = swap_int32(_buffer.msg.ground_speed) * 0.01f;
-            state.ground_course_cd  = swap_int32(_buffer.msg.ground_course) / 10000;
+            state.ground_course_cd  = wrap_360_cd(swap_int32(_buffer.msg.ground_course) / 10000);
             state.num_sats          = _buffer.msg.satellites;
 
             if (state.status >= AP_GPS::GPS_OK_FIX_2D) {

libraries/AP_GPS/AP_GPS_MTK19.cpp

@@ -144,7 +144,7 @@ restart:
 			}
             state.location.alt      = _buffer.msg.altitude;
             state.ground_speed      = _buffer.msg.ground_speed*0.01f;
-            state.ground_course_cd  = _buffer.msg.ground_course;
+            state.ground_course_cd  = wrap_360_cd(_buffer.msg.ground_course);
             state.num_sats          = _buffer.msg.satellites;
             state.hdop              = _buffer.msg.hdop;
             

libraries/AP_GPS/AP_GPS_NMEA.cpp

@@ -296,7 +296,7 @@ bool AP_GPS_NMEA::_term_complete()
                     state.location.lat     = _new_latitude;
                     state.location.lng     = _new_longitude;
                     state.ground_speed     = _new_speed*0.01f;
-                    state.ground_course_cd = _new_course;
+                    state.ground_course_cd = wrap_360_cd(_new_course);
                     make_gps_time(_new_date, _new_time * 10);
                     state.last_gps_time_ms = hal.scheduler->millis();
                     // To-Do: add support for proper reporting of 2D and 3D fix
@@ -314,7 +314,7 @@ bool AP_GPS_NMEA::_term_complete()
                     break;
                 case _GPS_SENTENCE_GPVTG:
                     state.ground_speed     = _new_speed*0.01f;
-                    state.ground_course_cd = _new_course;
+                    state.ground_course_cd = wrap_360_cd(_new_course);
                     // VTG has no fix indicator, can't change fix status
                     break;
                 }

libraries/AP_GPS/AP_GPS_PX4.cpp

@@ -63,7 +63,7 @@ AP_GPS_PX4::read(void)
                 state.location.alt = _gps_pos.alt/10;
 
                 state.ground_speed = _gps_pos.vel_m_s;
-                state.ground_course_cd = int32_t(double(_gps_pos.cog_rad) / M_PI * 18000. +.5);
+                state.ground_course_cd = wrap_360_cd(degrees(_gps_pos.cog_rad)*100);
                 state.hdop = _gps_pos.eph*100;
 
                 // convert epoch timestamp back to gps epoch - evil hack until we get the genuine

libraries/AP_GPS/AP_GPS_SBP.cpp

@@ -277,10 +277,7 @@ AP_GPS_SBP::_attempt_state_update()
         float ground_vector_sq = state.velocity[0]*state.velocity[0] + state.velocity[1]*state.velocity[1];
         state.ground_speed = safe_sqrt(ground_vector_sq);
 
-        state.ground_course_cd = (int32_t) 100*ToDeg(atan2f(state.velocity[1], state.velocity[0]));
-        if (state.ground_course_cd < 0) {
-          state.ground_course_cd += 36000;
-        }
+        state.ground_course_cd = wrap_360_cd((int32_t) 100*ToDeg(atan2f(state.velocity[1], state.velocity[0])));
 
         // Update position state
 

libraries/AP_GPS/AP_GPS_SIRF.cpp

@@ -186,7 +186,7 @@ AP_GPS_SIRF::_parse_gps(void)
         state.location.lng      = swap_int32(_buffer.nav.longitude);
         state.location.alt      = swap_int32(_buffer.nav.altitude_msl);
         state.ground_speed      = swap_int32(_buffer.nav.ground_speed)*0.01f;
-        state.ground_course_cd  = swap_int16(_buffer.nav.ground_course);
+        state.ground_course_cd  = wrap_360_cd(swap_int16(_buffer.nav.ground_course));
         state.num_sats          = _buffer.nav.satellites;
         fill_3d_velocity();
         return true;

libraries/AP_GPS/AP_GPS_UBLOX.cpp

@@ -634,7 +634,7 @@ AP_GPS_UBLOX::_parse_gps(void)
         Debug("MSG_VELNED");
         _last_vel_time         = _buffer.velned.time;
         state.ground_speed     = _buffer.velned.speed_2d*0.01f;          // m/s
-        state.ground_course_cd = _buffer.velned.heading_2d / 1000;       // Heading 2D deg * 100000 rescaled to deg * 100
+        state.ground_course_cd = wrap_360_cd(_buffer.velned.heading_2d / 1000);       // Heading 2D deg * 100000 rescaled to deg * 100
         state.have_vertical_velocity = true;
         state.velocity.x = _buffer.velned.ned_north * 0.01f;
         state.velocity.y = _buffer.velned.ned_east * 0.01f;