diff --git a/libraries/AP_HAL_SITL/SITL_State.cpp b/libraries/AP_HAL_SITL/SITL_State.cpp
index a0f0ccd899..a171361f58 100644
--- a/libraries/AP_HAL_SITL/SITL_State.cpp
+++ b/libraries/AP_HAL_SITL/SITL_State.cpp
@@ -72,9 +72,6 @@ void SITL_State::_sitl_setup(const char *home_str)
 
     // find the barometer object if it exists
     _sitl = AP::sitl();
-    _barometer = AP_Baro::get_singleton();
-    _ins = AP_InertialSensor::get_singleton();
-    _compass = Compass::get_singleton();
 
     if (_sitl != nullptr) {
         // setup some initial values
@@ -828,7 +825,7 @@ void SITL_State::_simulator_servos(struct sitl_input &input)
     uint32_t now = AP_HAL::micros();
     last_update_usec = now;
 
-    float altitude = _barometer?_barometer->get_altitude():0;
+    float altitude = AP::baro().get_altitude();
     float wind_speed = 0;
     float wind_direction = 0;
     float wind_dir_z = 0;
diff --git a/libraries/AP_HAL_SITL/SITL_State.h b/libraries/AP_HAL_SITL/SITL_State.h
index 69699b508c..8a2ab1ba4b 100644
--- a/libraries/AP_HAL_SITL/SITL_State.h
+++ b/libraries/AP_HAL_SITL/SITL_State.h
@@ -77,7 +77,6 @@ public:
         Blimp
     };
 
-    ssize_t gps_read(int fd, void *buf, size_t count);
     uint16_t pwm_output[SITL_NUM_CHANNELS];
     uint16_t pwm_input[SITL_RC_INPUT_CHANNELS];
     bool output_ready = false;
@@ -162,10 +161,7 @@ private:
     pid_t _parent_pid;
     uint32_t _update_count;
 
-    AP_Baro *_barometer;
-    AP_InertialSensor *_ins;
     Scheduler *_scheduler;
-    Compass *_compass;
 
     SocketAPM _sitl_rc_in{true};
     SITL::SIM *_sitl;
diff --git a/libraries/AP_HAL_SITL/UARTDriver.h b/libraries/AP_HAL_SITL/UARTDriver.h
index c9126f9262..6ed8a88a48 100644
--- a/libraries/AP_HAL_SITL/UARTDriver.h
+++ b/libraries/AP_HAL_SITL/UARTDriver.h
@@ -56,12 +56,6 @@ public:
     size_t write(uint8_t c) override;
     size_t write(const uint8_t *buffer, size_t size) override;
 
-    // file descriptor, exposed so SITL_State::loop_hook() can use it
-    int _fd;
-
-    // file descriptor for reading multicast packets
-    int _mc_fd;
-
     bool _unbuffered_writes;
 
     enum flow_control get_flow_control(void) override { return FLOW_CONTROL_ENABLE; }
@@ -88,6 +82,12 @@ public:
     uint64_t receive_time_constraint_us(uint16_t nbytes) override;
     
 private:
+
+    int _fd;
+
+    // file descriptor for reading multicast packets
+    int _mc_fd;
+
     uint8_t _portNumber;
     bool _connected = false; // true if a client has connected
     bool _use_send_recv = false;
diff --git a/libraries/AP_HAL_SITL/sitl_airspeed.cpp b/libraries/AP_HAL_SITL/sitl_airspeed.cpp
index af9bc15a7a..c5508b9b0b 100644
--- a/libraries/AP_HAL_SITL/sitl_airspeed.cpp
+++ b/libraries/AP_HAL_SITL/sitl_airspeed.cpp
@@ -45,13 +45,13 @@ void SITL_State::_update_airspeed(float airspeed)
     if (!is_zero(_sitl->arspd_fail_pressure[0])) {
         // compute a realistic pressure report given some level of trapper air pressure in the tube and our current altitude
         // algorithm taken from https://en.wikipedia.org/wiki/Calibrated_airspeed#Calculation_from_impact_pressure
-        float tube_pressure = fabsf(_sitl->arspd_fail_pressure[0] - _barometer->get_pressure() + _sitl->arspd_fail_pitot_pressure[0]);
+        float tube_pressure = fabsf(_sitl->arspd_fail_pressure[0] - AP::baro().get_pressure() + _sitl->arspd_fail_pitot_pressure[0]);
         airspeed = 340.29409348 * sqrt(5 * (pow((tube_pressure / SSL_AIR_PRESSURE + 1), 2.0/7.0) - 1.0));
     }
     if (!is_zero(_sitl->arspd_fail_pressure[1])) {
         // compute a realistic pressure report given some level of trapper air pressure in the tube and our current altitude
         // algorithm taken from https://en.wikipedia.org/wiki/Calibrated_airspeed#Calculation_from_impact_pressure
-        float tube_pressure = fabsf(_sitl->arspd_fail_pressure[1] - _barometer->get_pressure() + _sitl->arspd_fail_pitot_pressure[1]);
+        float tube_pressure = fabsf(_sitl->arspd_fail_pressure[1] - AP::baro().get_pressure() + _sitl->arspd_fail_pitot_pressure[1]);
         airspeed2 = 340.29409348 * sqrt(5 * (pow((tube_pressure / SSL_AIR_PRESSURE + 1), 2.0/7.0) - 1.0));
     }