diff --git a/libraries/AP_Quaternion/AP_Quaternion.cpp b/libraries/AP_Quaternion/AP_Quaternion.cpp
index 646b44806a..aedf1cd78b 100644
--- a/libraries/AP_Quaternion/AP_Quaternion.cpp
+++ b/libraries/AP_Quaternion/AP_Quaternion.cpp
@@ -242,12 +242,15 @@ void AP_Quaternion::update_MARG(float deltat, Vector3f &gyro, Vector3f &accel, V
 
 
 // Function to compute one quaternion iteration
-void AP_Quaternion::update(float deltat)
+void AP_Quaternion::update(void)
 {
 	Vector3f gyro, accel;
+	float deltat;
 
 	_imu->update();
 
+	delta_t = _imu->get_delta_time();
+
 	// get current IMU state
 	gyro = _imu->get_gyro();
 	gyro.x = -gyro.x;
diff --git a/libraries/AP_Quaternion/AP_Quaternion.h b/libraries/AP_Quaternion/AP_Quaternion.h
index 4d3cb03356..41c76904c3 100644
--- a/libraries/AP_Quaternion/AP_Quaternion.h
+++ b/libraries/AP_Quaternion/AP_Quaternion.h
@@ -43,7 +43,7 @@ public:
 	void		set_compass(Compass *compass);
 
 	// Methods
-	void 		update(float deltat);
+	void 		update(void);
 
 	// Euler angles (radians)
 	float		roll;
diff --git a/libraries/AP_Quaternion/examples/Quaternion/Quaternion.pde b/libraries/AP_Quaternion/examples/Quaternion/Quaternion.pde
index e5a5157db1..1296a7fbd3 100644
--- a/libraries/AP_Quaternion/examples/Quaternion/Quaternion.pde
+++ b/libraries/AP_Quaternion/examples/Quaternion/Quaternion.pde
@@ -111,7 +111,6 @@ void loop(void)
 	static uint16_t counter;
 	static uint32_t last_t, last_print, last_compass;
 	uint32_t now = micros();
-	float deltat;
 	static uint32_t compass_reads;
 	static uint32_t compass_time;
 
@@ -119,7 +118,6 @@ void loop(void)
 		last_t = now;
 		return;
 	}
-	deltat = (now - last_t) * 1.0e-6;
 	last_t = now;
 
 	if (now - last_compass > 100*1000UL) {
@@ -128,7 +126,7 @@ void loop(void)
 		last_compass = now;
 	}
 
-	quaternion.update(deltat);
+	quaternion.update();
 	counter++;
 
 	if (now - last_print >= 0.5e6) {