diff --git a/libraries/SITL/SIM_Aircraft.cpp b/libraries/SITL/SIM_Aircraft.cpp
index 13c6afd12a..ea09791dc9 100644
--- a/libraries/SITL/SIM_Aircraft.cpp
+++ b/libraries/SITL/SIM_Aircraft.cpp
@@ -159,17 +159,6 @@ void Aircraft::update_position(void)
 
     location.alt  = static_cast<int32_t>(home.alt - position.z * 100.0f);
 
-    // we only advance time if it hasn't been advanced already by the
-    // backend
-    // TODO : make this a function
-    if (last_time_us == time_now_us) {
-        time_now_us += frame_time_us;
-    }
-    last_time_us = time_now_us;
-    if (use_time_sync) {
-        sync_frame_time();
-    }
-
 #if 0
     // logging of raw sitl data
     Vector3f accel_ef = dcm * accel_body;
@@ -217,9 +206,17 @@ void Aircraft::update_mag_field_bf()
 }
 
 /* advance time by deltat in seconds */
-void Aircraft::time_advance(float deltat)
+void Aircraft::time_advance()
 {
-    time_now_us += deltat * 1.0e6f;
+    // we only advance time if it hasn't been advanced already by the
+    // backend
+    if (last_time_us == time_now_us) {
+        time_now_us += frame_time_us;
+    }
+    last_time_us = time_now_us;
+    if (use_time_sync) {
+        sync_frame_time();
+    }
 }
 
 /* setup the frame step time */
diff --git a/libraries/SITL/SIM_Aircraft.h b/libraries/SITL/SIM_Aircraft.h
index e88990b129..97c1556f5c 100644
--- a/libraries/SITL/SIM_Aircraft.h
+++ b/libraries/SITL/SIM_Aircraft.h
@@ -191,7 +191,7 @@ protected:
     void update_mag_field_bf(void);
 
     /* advance time by deltat in seconds */
-    void time_advance(float deltat);
+    void time_advance();
 
     /* setup the frame step time */
     void setup_frame_time(float rate, float speedup);
diff --git a/libraries/SITL/SIM_Balloon.cpp b/libraries/SITL/SIM_Balloon.cpp
index 847577f4dd..6c00cfa99a 100644
--- a/libraries/SITL/SIM_Balloon.cpp
+++ b/libraries/SITL/SIM_Balloon.cpp
@@ -70,6 +70,7 @@ void Balloon::update(const struct sitl_input &input)
     
     // update lat/lon/altitude
     update_position();
+    time_advance();
 
     // update magnetic field
     update_mag_field_bf();
diff --git a/libraries/SITL/SIM_CRRCSim.cpp b/libraries/SITL/SIM_CRRCSim.cpp
index 58aa117225..22db2e9d75 100644
--- a/libraries/SITL/SIM_CRRCSim.cpp
+++ b/libraries/SITL/SIM_CRRCSim.cpp
@@ -151,6 +151,7 @@ void CRRCSim::update(const struct sitl_input &input)
     send_servos(input);
     recv_fdm(input);
     update_position();
+    time_advance();
 
     // update magnetic field
     update_mag_field_bf();
diff --git a/libraries/SITL/SIM_Calibration.cpp b/libraries/SITL/SIM_Calibration.cpp
index 7159e9cbfb..119f8eccf3 100644
--- a/libraries/SITL/SIM_Calibration.cpp
+++ b/libraries/SITL/SIM_Calibration.cpp
@@ -48,6 +48,7 @@ void SITL::Calibration::update(const struct sitl_input& input)
     accel_body(0, 0, 0);
     update_dynamics(rot_accel);
     update_position();
+    time_advance();
 
     // update magnetic field
     update_mag_field_bf();
diff --git a/libraries/SITL/SIM_FlightAxis.cpp b/libraries/SITL/SIM_FlightAxis.cpp
index 32af5104d2..0d98e54e2e 100644
--- a/libraries/SITL/SIM_FlightAxis.cpp
+++ b/libraries/SITL/SIM_FlightAxis.cpp
@@ -366,6 +366,7 @@ void FlightAxis::update(const struct sitl_input &input)
     }
 
     update_position();
+    time_advance();
     time_now_us = (state.m_currentPhysicsTime_SEC - initial_time_s)*1.0e6;
 
     if (frame_counter++ % 1000 == 0) {
diff --git a/libraries/SITL/SIM_Gazebo.cpp b/libraries/SITL/SIM_Gazebo.cpp
index aebcb378d6..0093ee1083 100644
--- a/libraries/SITL/SIM_Gazebo.cpp
+++ b/libraries/SITL/SIM_Gazebo.cpp
@@ -164,6 +164,7 @@ void Gazebo::update(const struct sitl_input &input)
     recv_fdm(input);
     update_position();
 
+    time_advance();
     // update magnetic field
     update_mag_field_bf();
     drain_sockets();
diff --git a/libraries/SITL/SIM_Helicopter.cpp b/libraries/SITL/SIM_Helicopter.cpp
index de08a109be..ea22b4f017 100644
--- a/libraries/SITL/SIM_Helicopter.cpp
+++ b/libraries/SITL/SIM_Helicopter.cpp
@@ -164,6 +164,7 @@ void Helicopter::update(const struct sitl_input &input)
     
     // update lat/lon/altitude
     update_position();
+    time_advance();
 
     // update magnetic field
     update_mag_field_bf();
diff --git a/libraries/SITL/SIM_Multicopter.cpp b/libraries/SITL/SIM_Multicopter.cpp
index 0b00f2e2bd..355e5b78df 100644
--- a/libraries/SITL/SIM_Multicopter.cpp
+++ b/libraries/SITL/SIM_Multicopter.cpp
@@ -69,6 +69,7 @@ void MultiCopter::update(const struct sitl_input &input)
 
     // update lat/lon/altitude
     update_position();
+    time_advance();
 
     // update magnetic field
     update_mag_field_bf();
diff --git a/libraries/SITL/SIM_Plane.cpp b/libraries/SITL/SIM_Plane.cpp
index 2a80cc66de..2fea1a0813 100644
--- a/libraries/SITL/SIM_Plane.cpp
+++ b/libraries/SITL/SIM_Plane.cpp
@@ -316,6 +316,7 @@ void Plane::update(const struct sitl_input &input)
     
     // update lat/lon/altitude
     update_position();
+    time_advance();
 
     // update magnetic field
     update_mag_field_bf();
diff --git a/libraries/SITL/SIM_QuadPlane.cpp b/libraries/SITL/SIM_QuadPlane.cpp
index be9e9bb9ad..139dfc45f1 100644
--- a/libraries/SITL/SIM_QuadPlane.cpp
+++ b/libraries/SITL/SIM_QuadPlane.cpp
@@ -114,6 +114,7 @@ void QuadPlane::update(const struct sitl_input &input)
 
     // update lat/lon/altitude
     update_position();
+    time_advance();
 
     // update magnetic field
     update_mag_field_bf();
diff --git a/libraries/SITL/SIM_Rover.cpp b/libraries/SITL/SIM_Rover.cpp
index c4ad53671b..b7c6ed0da9 100644
--- a/libraries/SITL/SIM_Rover.cpp
+++ b/libraries/SITL/SIM_Rover.cpp
@@ -151,6 +151,7 @@ void SimRover::update(const struct sitl_input &input)
 
     // update lat/lon/altitude
     update_position();
+    time_advance();
 
     // update magnetic field
     update_mag_field_bf();
diff --git a/libraries/SITL/SIM_SingleCopter.cpp b/libraries/SITL/SIM_SingleCopter.cpp
index 50aa9f5fd3..f4e28828b7 100644
--- a/libraries/SITL/SIM_SingleCopter.cpp
+++ b/libraries/SITL/SIM_SingleCopter.cpp
@@ -101,6 +101,7 @@ void SingleCopter::update(const struct sitl_input &input)
     
     // update lat/lon/altitude
     update_position();
+    time_advance();
 
     // update magnetic field
     update_mag_field_bf();
diff --git a/libraries/SITL/SIM_Submarine.cpp b/libraries/SITL/SIM_Submarine.cpp
index 1611e5e302..5668f7d9e0 100644
--- a/libraries/SITL/SIM_Submarine.cpp
+++ b/libraries/SITL/SIM_Submarine.cpp
@@ -107,6 +107,7 @@ void Submarine::update(const struct sitl_input &input)
 
     // update lat/lon/altitude
     update_position();
+    time_advance();
 
     // update magnetic field
     update_mag_field_bf();
diff --git a/libraries/SITL/SIM_Tracker.cpp b/libraries/SITL/SIM_Tracker.cpp
index c2391685e6..e0da8ae32f 100644
--- a/libraries/SITL/SIM_Tracker.cpp
+++ b/libraries/SITL/SIM_Tracker.cpp
@@ -134,6 +134,7 @@ void Tracker::update(const struct sitl_input &input)
     // new velocity vector
     velocity_ef.zero();
     update_position();
+    time_advance();
 
     // update magnetic field
     update_mag_field_bf();
diff --git a/libraries/SITL/SIM_XPlane.cpp b/libraries/SITL/SIM_XPlane.cpp
index a2ec5ef277..2b4dc8f02b 100644
--- a/libraries/SITL/SIM_XPlane.cpp
+++ b/libraries/SITL/SIM_XPlane.cpp
@@ -297,6 +297,7 @@ bool XPlane::receive_data(void)
     }
     position = pos + position_zero;
     update_position();
+    time_advance();
 
     accel_earth = dcm * accel_body;
     accel_earth.z += GRAVITY_MSS;
@@ -314,6 +315,7 @@ bool XPlane::receive_data(void)
         position.y = 0;
         position.z = 0;
         update_position();
+        time_advance();
     }
 
     update_mag_field_bf();
@@ -355,6 +357,7 @@ failed:
     velocity_air_bf = dcm.transposed() * velocity_air_ef;
 
     update_position();
+    time_advance();
     update_mag_field_bf();
     report.frame_count++;
     return false;
diff --git a/libraries/SITL/SIM_last_letter.cpp b/libraries/SITL/SIM_last_letter.cpp
index e7069d3653..31f2b2b337 100644
--- a/libraries/SITL/SIM_last_letter.cpp
+++ b/libraries/SITL/SIM_last_letter.cpp
@@ -130,6 +130,7 @@ void last_letter::update(const struct sitl_input &input)
     sync_frame_time();
 
     update_position();
+    time_advance();
     // update magnetic field
     update_mag_field_bf();
 }