diff --git a/APMrover2/Parameters.cpp b/APMrover2/Parameters.cpp
index 2af51455e2..47cee013a6 100644
--- a/APMrover2/Parameters.cpp
+++ b/APMrover2/Parameters.cpp
@@ -485,7 +485,7 @@ const AP_Param::Info Rover::var_info[] PROGMEM = {
 #if CONFIG_HAL_BOARD == HAL_BOARD_SITL
     // @Group: SIM_
     // @Path: ../libraries/SITL/SITL.cpp
-    GOBJECT(sitl, "SIM_", SITL),
+    GOBJECT(sitl, "SIM_", SITL::SITL),
 #endif
 
     // @Group: AHRS_
diff --git a/APMrover2/Rover.h b/APMrover2/Rover.h
index dac01e27f2..197c3ef84e 100644
--- a/APMrover2/Rover.h
+++ b/APMrover2/Rover.h
@@ -169,7 +169,7 @@ private:
     AP_RSSI rssi;          
 
 #if CONFIG_HAL_BOARD == HAL_BOARD_SITL
-    SITL sitl;
+    SITL::SITL sitl;
 #endif
 
     // GCS handling
diff --git a/AntennaTracker/Parameters.cpp b/AntennaTracker/Parameters.cpp
index 47f6c5f868..cdd293b2e8 100644
--- a/AntennaTracker/Parameters.cpp
+++ b/AntennaTracker/Parameters.cpp
@@ -241,7 +241,7 @@ const AP_Param::Info Tracker::var_info[] PROGMEM = {
 #if CONFIG_HAL_BOARD == HAL_BOARD_SITL
     // @Group: SIM_
     // @Path: ../libraries/SITL/SITL.cpp
-    GOBJECT(sitl, "SIM_", SITL),
+    GOBJECT(sitl, "SIM_", SITL::SITL),
 #endif
 
     // @Group: BRD_
diff --git a/AntennaTracker/Tracker.h b/AntennaTracker/Tracker.h
index c4a198575e..4e3fcf1761 100644
--- a/AntennaTracker/Tracker.h
+++ b/AntennaTracker/Tracker.h
@@ -122,7 +122,7 @@ private:
 #endif
 
 #if CONFIG_HAL_BOARD == HAL_BOARD_SITL
-    SITL sitl;
+    SITL::SITL sitl;
 #endif
     
     /**
diff --git a/ArduCopter/Copter.h b/ArduCopter/Copter.h
index 1964845338..710918b292 100644
--- a/ArduCopter/Copter.h
+++ b/ArduCopter/Copter.h
@@ -186,7 +186,7 @@ private:
     AP_AHRS_NavEKF ahrs{ins, barometer, gps, sonar, EKF, EKF2, AP_AHRS_NavEKF::FLAG_ALWAYS_USE_EKF};
 
 #if CONFIG_HAL_BOARD == HAL_BOARD_SITL
-    SITL sitl;
+    SITL::SITL sitl;
 #endif
 
     // Mission library
diff --git a/ArduCopter/Parameters.cpp b/ArduCopter/Parameters.cpp
index e748410650..6504d883f7 100644
--- a/ArduCopter/Parameters.cpp
+++ b/ArduCopter/Parameters.cpp
@@ -974,7 +974,7 @@ const AP_Param::Info Copter::var_info[] PROGMEM = {
 #endif
 
 #if CONFIG_HAL_BOARD == HAL_BOARD_SITL
-    GOBJECT(sitl, "SIM_", SITL),
+    GOBJECT(sitl, "SIM_", SITL::SITL),
 #endif
 
     // @Group: GND_
diff --git a/ArduPlane/Parameters.cpp b/ArduPlane/Parameters.cpp
index 1323533549..c7e257fded 100644
--- a/ArduPlane/Parameters.cpp
+++ b/ArduPlane/Parameters.cpp
@@ -1161,7 +1161,7 @@ const AP_Param::Info Plane::var_info[] PROGMEM = {
 #if CONFIG_HAL_BOARD == HAL_BOARD_SITL
     // @Group: SIM_
     // @Path: ../libraries/SITL/SITL.cpp
-    GOBJECT(sitl, "SIM_", SITL),
+    GOBJECT(sitl, "SIM_", SITL::SITL),
 #endif
 
 #if OBC_FAILSAFE == ENABLED
diff --git a/ArduPlane/Plane.h b/ArduPlane/Plane.h
index 0ed566c95b..31f6779263 100644
--- a/ArduPlane/Plane.h
+++ b/ArduPlane/Plane.h
@@ -224,7 +224,7 @@ private:
     AP_SteerController steerController {ahrs};
 
 #if CONFIG_HAL_BOARD == HAL_BOARD_SITL
-    SITL sitl;
+    SITL::SITL sitl;
 #endif
 
     // Training mode
diff --git a/Tools/Replay/Replay.cpp b/Tools/Replay/Replay.cpp
index 54e592aafc..25b236ce16 100644
--- a/Tools/Replay/Replay.cpp
+++ b/Tools/Replay/Replay.cpp
@@ -230,7 +230,7 @@ private:
     ReplayVehicle &_vehicle;
 
 #if CONFIG_HAL_BOARD == HAL_BOARD_SITL
-    SITL sitl;
+    SITL::SITL sitl;
 #endif
 
     LogReader logreader{_vehicle.ahrs, _vehicle.ins, _vehicle.barometer, _vehicle.compass, _vehicle.gps, _vehicle.airspeed, _vehicle.dataflash, log_structure, ARRAY_SIZE(log_structure), nottypes};
diff --git a/libraries/AP_HAL_SITL/SITL_State.cpp b/libraries/AP_HAL_SITL/SITL_State.cpp
index eaa0174b3c..c3c4e9d831 100644
--- a/libraries/AP_HAL_SITL/SITL_State.cpp
+++ b/libraries/AP_HAL_SITL/SITL_State.cpp
@@ -22,6 +22,7 @@
 extern const AP_HAL::HAL& hal;
 
 using namespace HALSITL;
+using namespace SITL;
 
 void SITL_State::_set_param_default(const char *parm)
 {
@@ -74,7 +75,7 @@ void SITL_State::_sitl_setup(void)
     fprintf(stdout, "Starting SITL input\n");
 
     // find the barometer object if it exists
-    _sitl = (SITL *)AP_Param::find_object("SIM_");
+    _sitl = (SITL::SITL *)AP_Param::find_object("SIM_");
     _barometer = (AP_Baro *)AP_Param::find_object("GND_");
     _ins = (AP_InertialSensor *)AP_Param::find_object("INS_");
     _compass = (Compass *)AP_Param::find_object("COMPASS_");
diff --git a/libraries/AP_HAL_SITL/SITL_State.h b/libraries/AP_HAL_SITL/SITL_State.h
index 3556cbce21..d56fec7ff6 100644
--- a/libraries/AP_HAL_SITL/SITL_State.h
+++ b/libraries/AP_HAL_SITL/SITL_State.h
@@ -109,7 +109,7 @@ private:
                      float airspeed,	float altitude);
     void _fdm_input(void);
     void _fdm_input_local(void);
-    void _simulator_servos(Aircraft::sitl_input &input);
+    void _simulator_servos(SITL::Aircraft::sitl_input &input);
     void _simulator_output(bool synthetic_clock_mode);
     void _apply_servo_filter(float deltat);
     uint16_t _airspeed_sensor(float airspeed);
@@ -142,7 +142,7 @@ private:
     AP_Terrain *_terrain;
 
     int _sitl_fd;
-    SITL *_sitl;
+    SITL::SITL *_sitl;
     uint16_t _rcout_port;
     uint16_t _simin_port;
     float _current;
@@ -190,11 +190,11 @@ private:
     uint32_t delayed_time_baro;
 
     // internal SITL model
-    Aircraft *sitl_model;
+    SITL::Aircraft *sitl_model;
 
     // simulated gimbal
     bool enable_gimbal;
-    Gimbal *gimbal;
+    SITL::Gimbal *gimbal;
 
     // TCP address to connect uartC to
     const char *_client_address;
diff --git a/libraries/AP_HAL_SITL/SITL_cmdline.cpp b/libraries/AP_HAL_SITL/SITL_cmdline.cpp
index a449c13676..09e5054b4b 100644
--- a/libraries/AP_HAL_SITL/SITL_cmdline.cpp
+++ b/libraries/AP_HAL_SITL/SITL_cmdline.cpp
@@ -26,6 +26,7 @@
 extern const AP_HAL::HAL& hal;
 
 using namespace HALSITL;
+using namespace SITL;
 
 // catch floating point exceptions
 static void _sig_fpe(int signum)
diff --git a/libraries/AP_HAL_SITL/sitl_gps.cpp b/libraries/AP_HAL_SITL/sitl_gps.cpp
index 039b456960..3e7d91c847 100644
--- a/libraries/AP_HAL_SITL/sitl_gps.cpp
+++ b/libraries/AP_HAL_SITL/sitl_gps.cpp
@@ -801,36 +801,36 @@ void SITL_State::_update_gps(double latitude, double longitude, float altitude,
         return;
     }
 
-    switch ((SITL::GPSType)_sitl->gps_type.get()) {
-    case SITL::GPS_TYPE_NONE:
+    switch ((SITL::SITL::GPSType)_sitl->gps_type.get()) {
+    case SITL::SITL::GPS_TYPE_NONE:
         // no GPS attached
         break;
 
-    case SITL::GPS_TYPE_UBLOX:
+    case SITL::SITL::GPS_TYPE_UBLOX:
         _update_gps_ubx(&d);
         break;
 
-    case SITL::GPS_TYPE_MTK:
+    case SITL::SITL::GPS_TYPE_MTK:
         _update_gps_mtk(&d);
         break;
 
-    case SITL::GPS_TYPE_MTK16:
+    case SITL::SITL::GPS_TYPE_MTK16:
         _update_gps_mtk16(&d);
         break;
 
-    case SITL::GPS_TYPE_MTK19:
+    case SITL::SITL::GPS_TYPE_MTK19:
         _update_gps_mtk19(&d);
         break;
 
-    case SITL::GPS_TYPE_NMEA:
+    case SITL::SITL::GPS_TYPE_NMEA:
         _update_gps_nmea(&d);
         break;
 
-    case SITL::GPS_TYPE_SBP:
+    case SITL::SITL::GPS_TYPE_SBP:
         _update_gps_sbp(&d);
         break;
 
-    case SITL::GPS_TYPE_FILE:
+    case SITL::SITL::GPS_TYPE_FILE:
         _update_gps_file(&d);
         break;
 
diff --git a/libraries/SITL/SIM_Aircraft.cpp b/libraries/SITL/SIM_Aircraft.cpp
index a2b95a1728..1f684862c9 100644
--- a/libraries/SITL/SIM_Aircraft.cpp
+++ b/libraries/SITL/SIM_Aircraft.cpp
@@ -30,6 +30,8 @@
 #include <Mmsystem.h>
 #endif
 
+namespace SITL {
+
 /*
   parent class for all simulator types
  */
@@ -290,4 +292,7 @@ void Aircraft::set_speedup(float speedup)
 {
     setup_frame_time(rate_hz, speedup);
 }
+
+} // namespace SITL
+
 #endif // CONFIG_HAL_BOARD
diff --git a/libraries/SITL/SIM_Aircraft.h b/libraries/SITL/SIM_Aircraft.h
index f029b973f7..fb3f6c2863 100644
--- a/libraries/SITL/SIM_Aircraft.h
+++ b/libraries/SITL/SIM_Aircraft.h
@@ -24,6 +24,8 @@
 #include <AP_Common/AP_Common.h>
 #include <AP_Math/AP_Math.h>
 
+namespace SITL {
+
 /*
   parent class for all simulator types
  */
@@ -136,5 +138,7 @@ private:
     const uint32_t min_sleep_time;
 };
 
+} // namespace SITL
+
 #endif // _SIM_AIRCRAFT_H
 
diff --git a/libraries/SITL/SIM_Balloon.cpp b/libraries/SITL/SIM_Balloon.cpp
index 9fe58cfe30..2fe182de2b 100644
--- a/libraries/SITL/SIM_Balloon.cpp
+++ b/libraries/SITL/SIM_Balloon.cpp
@@ -22,6 +22,8 @@
 #include "SIM_Balloon.h"
 #include <stdio.h>
 
+namespace SITL {
+
 /*
   constructor
  */
@@ -119,4 +121,7 @@ void Balloon::update(const struct sitl_input &input)
     // update lat/lon/altitude
     update_position();
 }
+
+} // namespace SITL
+
 #endif // CONFIG_HAL_BOARD
diff --git a/libraries/SITL/SIM_Balloon.h b/libraries/SITL/SIM_Balloon.h
index 8d58643198..7a41a21714 100644
--- a/libraries/SITL/SIM_Balloon.h
+++ b/libraries/SITL/SIM_Balloon.h
@@ -22,6 +22,8 @@
 
 #include "SIM_Aircraft.h"
 
+namespace SITL {
+
 /*
   a balloon simulator
  */
@@ -47,5 +49,6 @@ private:
     bool released = false;
 };
 
+} // namespace SITL
 
 #endif // _SIM_BALLOON_H
diff --git a/libraries/SITL/SIM_CRRCSim.cpp b/libraries/SITL/SIM_CRRCSim.cpp
index f3a910de6d..e0b73dd5b6 100644
--- a/libraries/SITL/SIM_CRRCSim.cpp
+++ b/libraries/SITL/SIM_CRRCSim.cpp
@@ -24,6 +24,8 @@
 
 extern const AP_HAL::HAL& hal;
 
+namespace SITL {
+
 /*
   constructor
  */
@@ -152,4 +154,7 @@ void CRRCSim::update(const struct sitl_input &input)
     recv_fdm(input);
     update_position();
 }
+
+} // namespace SITL
+
 #endif // CONFIG_HAL_BOARD
diff --git a/libraries/SITL/SIM_CRRCSim.h b/libraries/SITL/SIM_CRRCSim.h
index 663701c4ae..be0caa2797 100644
--- a/libraries/SITL/SIM_CRRCSim.h
+++ b/libraries/SITL/SIM_CRRCSim.h
@@ -23,6 +23,8 @@
 #include "SIM_Aircraft.h"
 #include <AP_HAL/utility/Socket.h>
 
+namespace SITL {
+
 /*
   a CRRCSim simulator
  */
@@ -76,5 +78,6 @@ private:
     SocketAPM sock;
 };
 
+} // namespace SITL
 
 #endif // _SIM_CRRCSIM_H
diff --git a/libraries/SITL/SIM_Gazebo.cpp b/libraries/SITL/SIM_Gazebo.cpp
index 353b4d73ca..a02609dcf6 100644
--- a/libraries/SITL/SIM_Gazebo.cpp
+++ b/libraries/SITL/SIM_Gazebo.cpp
@@ -24,6 +24,8 @@
 
 extern const AP_HAL::HAL& hal;
 
+namespace SITL {
+
 /*
   constructor
  */
@@ -127,4 +129,7 @@ void Gazebo::update(const struct sitl_input &input)
     recv_fdm(input);
     update_position();
 }
+
+} // namespace SITL
+
 #endif // CONFIG_HAL_BOARD
diff --git a/libraries/SITL/SIM_Gazebo.h b/libraries/SITL/SIM_Gazebo.h
index 7b64bc96bc..120cff8ea5 100644
--- a/libraries/SITL/SIM_Gazebo.h
+++ b/libraries/SITL/SIM_Gazebo.h
@@ -23,6 +23,8 @@
 #include "SIM_Aircraft.h"
 #include <AP_HAL/utility/Socket.h>
 
+namespace SITL {
+
 /*
   Gazebo simulator
  */
@@ -68,5 +70,6 @@ private:
     SocketAPM sock;
 };
 
+} // namespace SITL
 
 #endif // _SIM_GAZEBO_H
diff --git a/libraries/SITL/SIM_Gimbal.cpp b/libraries/SITL/SIM_Gimbal.cpp
index 789413ecc2..181e6ed2e2 100644
--- a/libraries/SITL/SIM_Gimbal.cpp
+++ b/libraries/SITL/SIM_Gimbal.cpp
@@ -24,6 +24,8 @@
 
 extern const AP_HAL::HAL& hal;
 
+namespace SITL {
+
 Gimbal::Gimbal(const struct sitl_fdm &_fdm) :
     fdm(_fdm),
     target_address("127.0.0.1"),
@@ -291,4 +293,7 @@ void Gimbal::send_report(void)
         delta_angle.zero();
     }
 }
+
+} // namespace SITL
+
 #endif // CONFIG_HAL_BOARD
diff --git a/libraries/SITL/SIM_Gimbal.h b/libraries/SITL/SIM_Gimbal.h
index 92bd43f1ce..9748c7ed52 100644
--- a/libraries/SITL/SIM_Gimbal.h
+++ b/libraries/SITL/SIM_Gimbal.h
@@ -24,6 +24,8 @@
 #if CONFIG_HAL_BOARD == HAL_BOARD_SITL
 #include <AP_HAL/utility/Socket.h>
 
+namespace SITL {
+
 class Gimbal
 {
 public:
@@ -105,6 +107,9 @@ private:
 
     void send_report(void);
 };
+
+}  // namespace SITL
+
 #endif // CONFIG_HAL_BOARD
 
 #endif // _SIM_GIMBAL_H
diff --git a/libraries/SITL/SIM_Helicopter.cpp b/libraries/SITL/SIM_Helicopter.cpp
index 36c24dfd92..e8329c54a5 100644
--- a/libraries/SITL/SIM_Helicopter.cpp
+++ b/libraries/SITL/SIM_Helicopter.cpp
@@ -22,6 +22,8 @@
 #include "SIM_Helicopter.h"
 #include <stdio.h>
 
+namespace SITL {
+
 /*
   constructor
  */
@@ -209,4 +211,7 @@ void Helicopter::update(const struct sitl_input &input)
     // update lat/lon/altitude
     update_position();
 }
+
+} // namespace SITL
+
 #endif // CONFIG_HAL_BOARD
diff --git a/libraries/SITL/SIM_Helicopter.h b/libraries/SITL/SIM_Helicopter.h
index 0a573aa7ad..e02f3e4988 100644
--- a/libraries/SITL/SIM_Helicopter.h
+++ b/libraries/SITL/SIM_Helicopter.h
@@ -22,6 +22,8 @@
 
 #include "SIM_Aircraft.h"
 
+namespace SITL {
+
 /*
   a helicopter simulator
  */
@@ -59,5 +61,6 @@ private:
     bool gas_heli = false;
 };
 
+} // namespace SITL
 
 #endif // _SIM_HELICOPTER_H
diff --git a/libraries/SITL/SIM_JSBSim.cpp b/libraries/SITL/SIM_JSBSim.cpp
index b4856c455e..d4d4a48c84 100644
--- a/libraries/SITL/SIM_JSBSim.cpp
+++ b/libraries/SITL/SIM_JSBSim.cpp
@@ -30,6 +30,8 @@
 
 extern const AP_HAL::HAL& hal;
 
+namespace SITL {
+
 // the asprintf() calls are not worth checking for SITL
 #pragma GCC diagnostic ignored "-Wunused-result"
 
@@ -456,4 +458,7 @@ void JSBSim::update(const struct sitl_input &input)
     sync_frame_time();
     drain_control_socket();
 }
+
+} // namespace SITL
+
 #endif // CONFIG_HAL_BOARD
diff --git a/libraries/SITL/SIM_JSBSim.h b/libraries/SITL/SIM_JSBSim.h
index 894fd18f60..125133084e 100644
--- a/libraries/SITL/SIM_JSBSim.h
+++ b/libraries/SITL/SIM_JSBSim.h
@@ -23,6 +23,8 @@
 #include "SIM_Aircraft.h"
 #include <AP_HAL/utility/Socket.h>
 
+namespace SITL {
+
 /*
   a Jsbsim simulator
  */
@@ -175,4 +177,6 @@ public:
     void ByteSwap(void);
 };
 
+} // namespace SITL
+
 #endif // _SIM_JSBSIM_H
diff --git a/libraries/SITL/SIM_Multicopter.cpp b/libraries/SITL/SIM_Multicopter.cpp
index 4c8f7fa863..b88c549624 100644
--- a/libraries/SITL/SIM_Multicopter.cpp
+++ b/libraries/SITL/SIM_Multicopter.cpp
@@ -22,6 +22,8 @@
 #include "SIM_Multicopter.h"
 #include <stdio.h>
 
+namespace SITL {
+
 Motor m(90,  false,  1);
 
 static const Motor quad_plus_motors[4] =
@@ -226,4 +228,7 @@ void MultiCopter::update(const struct sitl_input &input)
     // update lat/lon/altitude
     update_position();
 }
+
+} // namespace SITL
+
 #endif // CONFIG_HAL_BOARD
diff --git a/libraries/SITL/SIM_Multicopter.h b/libraries/SITL/SIM_Multicopter.h
index 8c85b39482..8d1db9adcb 100644
--- a/libraries/SITL/SIM_Multicopter.h
+++ b/libraries/SITL/SIM_Multicopter.h
@@ -22,6 +22,8 @@
 
 #include "SIM_Aircraft.h"
 
+namespace SITL {
+
 /*
   class to describe a motor position
  */
@@ -80,5 +82,6 @@ private:
     float thrust_scale;
 };
 
+} // namespace SITL
 
 #endif // _SIM_MULTICOPTER_H
diff --git a/libraries/SITL/SIM_Rover.cpp b/libraries/SITL/SIM_Rover.cpp
index 2a3f42fd83..f6f46a81db 100644
--- a/libraries/SITL/SIM_Rover.cpp
+++ b/libraries/SITL/SIM_Rover.cpp
@@ -23,6 +23,8 @@
 #include <stdio.h>
 #include <string.h>
 
+namespace SITL {
+
 /*
   constructor
  */
@@ -157,4 +159,7 @@ void SimRover::update(const struct sitl_input &input)
     // update lat/lon/altitude
     update_position();
 }
+
+} // namespace SITL
+
 #endif // CONFIG_HAL_BOARD
diff --git a/libraries/SITL/SIM_Rover.h b/libraries/SITL/SIM_Rover.h
index 6dd6e1ed36..a823d78b26 100644
--- a/libraries/SITL/SIM_Rover.h
+++ b/libraries/SITL/SIM_Rover.h
@@ -22,6 +22,8 @@
 
 #include "SIM_Aircraft.h"
 
+namespace SITL {
+
 /*
   a rover simulator
  */
@@ -53,5 +55,6 @@ private:
     float calc_lat_accel(float steering_angle, float speed);
 };
 
+} // namespace SITL
 
 #endif // _SIM_ROVER_H
diff --git a/libraries/SITL/SIM_Tracker.cpp b/libraries/SITL/SIM_Tracker.cpp
index 956748d3c3..e8820c7f92 100644
--- a/libraries/SITL/SIM_Tracker.cpp
+++ b/libraries/SITL/SIM_Tracker.cpp
@@ -21,6 +21,8 @@
 #if CONFIG_HAL_BOARD == HAL_BOARD_SITL
 #include <stdio.h>
 
+namespace SITL {
+
 Tracker::Tracker(const char *home_str, const char *frame_str) :
 Aircraft(home_str, frame_str)
 {}
@@ -135,4 +137,6 @@ void Tracker::update(const struct sitl_input &input)
     update_position();
 }
 
+} // namespace SITL
+
 #endif
diff --git a/libraries/SITL/SIM_Tracker.h b/libraries/SITL/SIM_Tracker.h
index 81e4dff014..2ab298e7ca 100644
--- a/libraries/SITL/SIM_Tracker.h
+++ b/libraries/SITL/SIM_Tracker.h
@@ -22,6 +22,8 @@
 
 #include "SIM_Aircraft.h"
 
+namespace SITL {
+
 /*
   a antenna tracker simulator
  */
@@ -57,4 +59,6 @@ private:
     void update_onoff_servos(float &yaw_rate, float &pitch_rate);
 };
 
+} // namespace SITL
+
 #endif
diff --git a/libraries/SITL/SIM_last_letter.cpp b/libraries/SITL/SIM_last_letter.cpp
index 9a0f26e4bd..a9c5bd2773 100644
--- a/libraries/SITL/SIM_last_letter.cpp
+++ b/libraries/SITL/SIM_last_letter.cpp
@@ -27,6 +27,8 @@
 
 extern const AP_HAL::HAL& hal;
 
+namespace SITL {
+
 /*
   constructor
  */
@@ -143,4 +145,7 @@ void last_letter::update(const struct sitl_input &input)
     recv_fdm(input);
     sync_frame_time();
 }
+
+} // namespace SITL
+
 #endif // CONFIG_HAL_BOARD
diff --git a/libraries/SITL/SIM_last_letter.h b/libraries/SITL/SIM_last_letter.h
index cbae765efe..0d4b944fbf 100644
--- a/libraries/SITL/SIM_last_letter.h
+++ b/libraries/SITL/SIM_last_letter.h
@@ -23,6 +23,8 @@
 #include "SIM_Aircraft.h"
 #include <AP_HAL/utility/Socket.h>
 
+namespace SITL {
+
 /*
   a last_letter simulator
  */
@@ -74,5 +76,6 @@ private:
     const char *frame_str;
 };
 
+} // namespace SITL
 
 #endif // _SIM_LAST_LETTER_H
diff --git a/libraries/SITL/SITL.cpp b/libraries/SITL/SITL.cpp
index 92aa605861..1d5be1bbf6 100644
--- a/libraries/SITL/SITL.cpp
+++ b/libraries/SITL/SITL.cpp
@@ -25,6 +25,8 @@
 
 extern const AP_HAL::HAL& hal;
 
+namespace SITL {
+
 // table of user settable parameters
 const AP_Param::GroupInfo SITL::var_info[] PROGMEM = {
     AP_GROUPINFO("BARO_RND",   0, SITL,  baro_noise,  0.2f),
@@ -170,3 +172,4 @@ Vector3f SITL::convert_earth_frame(const Matrix3f &dcm, const Vector3f &gyro)
     return Vector3f(phiDot, thetaDot, psiDot);
 }
 
+} // namespace SITL
diff --git a/libraries/SITL/SITL.h b/libraries/SITL/SITL.h
index bed0d0ab74..5b4bcc9009 100644
--- a/libraries/SITL/SITL.h
+++ b/libraries/SITL/SITL.h
@@ -9,6 +9,8 @@
 #include <GCS_MAVLink/GCS_MAVLink.h>
 #include <DataFlash/DataFlash.h>
 
+namespace SITL {
+
 struct PACKED sitl_fdm {
     // this is the packet sent by the simulator
     // to the APM executable to update the simulator state
@@ -119,4 +121,6 @@ public:
     static Vector3f convert_earth_frame(const Matrix3f &dcm, const Vector3f &gyro);
 };
 
+} // namespace SITL
+
 #endif // __SITL_H__