diff --git a/conf/airframes/booz2_a1.xml b/conf/airframes/booz2_a1.xml
index ea818ff011..d3d1fbfb68 100644
--- a/conf/airframes/booz2_a1.xml
+++ b/conf/airframes/booz2_a1.xml
@@ -73,6 +73,11 @@
    <define name="BODY_TO_IMU_PHI"   value="ANGLE_BFP_OF_REAL(RadOfDeg(4.))"/>
    <define name="BODY_TO_IMU_THETA" value="ANGLE_BFP_OF_REAL(RadOfDeg(3.))"/>
    <define name="BODY_TO_IMU_PSI"   value="ANGLE_BFP_OF_REAL(RadOfDeg(0.))"/>
+<!--
+   <define name="BODY_TO_IMU_PHI"   value="ANGLE_BFP_OF_REAL(RadOfDeg(0.))"/>
+   <define name="BODY_TO_IMU_THETA" value="ANGLE_BFP_OF_REAL(RadOfDeg(0.))"/>
+   <define name="BODY_TO_IMU_PSI"   value="ANGLE_BFP_OF_REAL(RadOfDeg(0.))"/>
+-->
 
   </section>
 
diff --git a/conf/simulator/nps/nps_sensors_params_booz2_a1.h b/conf/simulator/nps/nps_sensors_params_booz2_a1.h
index 2216a40dc6..34c9f1cbf2 100644
--- a/conf/simulator/nps/nps_sensors_params_booz2_a1.h
+++ b/conf/simulator/nps/nps_sensors_params_booz2_a1.h
@@ -27,10 +27,15 @@
 
 #include "airframe.h"
 
-
+#if 1
 #define NPS_BODY_TO_IMU_PHI    RadOfDeg(4.)
 #define NPS_BODY_TO_IMU_THETA  RadOfDeg(3.)
 #define NPS_BODY_TO_IMU_PSI    RadOfDeg(0.)
+#else
+#define NPS_BODY_TO_IMU_PHI    RadOfDeg(0.)
+#define NPS_BODY_TO_IMU_THETA  RadOfDeg(0.)
+#define NPS_BODY_TO_IMU_PSI    RadOfDeg(0.)
+#endif
 
 /* 
  * Accelerometer 
@@ -38,17 +43,17 @@
 #define NPS_ACCEL_RESOLUTION      (65536)
 /* ms-2 */
 /* aka 2^10/ACCEL_X_SENS  */
-#define NPS_ACCEL_SENSITIVITY_XX  -408.92695
-#define NPS_ACCEL_SENSITIVITY_YY  -412.69325
-#define NPS_ACCEL_SENSITIVITY_ZZ  -407.32522
+#define NPS_ACCEL_SENSITIVITY_XX  ACCEL_BFP_OF_REAL(-1./2.50411474)
+#define NPS_ACCEL_SENSITIVITY_YY  ACCEL_BFP_OF_REAL(-1./2.48126183)
+#define NPS_ACCEL_SENSITIVITY_ZZ  ACCEL_BFP_OF_REAL(-1./2.51396167)
 
 #define NPS_ACCEL_NEUTRAL_X       32081
 #define NPS_ACCEL_NEUTRAL_Y       33738
 #define NPS_ACCEL_NEUTRAL_Z       32441
 /* m2s-4 */
-#define NPS_ACCEL_NOISE_STD_DEV_X 1.e-1
-#define NPS_ACCEL_NOISE_STD_DEV_Y 1.e-1
-#define NPS_ACCEL_NOISE_STD_DEV_Z 1.1e-1
+#define NPS_ACCEL_NOISE_STD_DEV_X 0.e-1
+#define NPS_ACCEL_NOISE_STD_DEV_Y 0.e-1
+#define NPS_ACCEL_NOISE_STD_DEV_Z 0.e-1
 /* ms-2 */
 #define NPS_ACCEL_BIAS_X          0
 #define NPS_ACCEL_BIAS_Y          0
@@ -64,9 +69,9 @@
 #define NPS_GYRO_RESOLUTION       65536
 
 /* 2^12/GYRO_X_SENS */
-#define NPS_GYRO_SENSITIVITY_PP   ( 4055.)
-#define NPS_GYRO_SENSITIVITY_QQ   (-4055.)
-#define NPS_GYRO_SENSITIVITY_RR   (-4055.)
+#define NPS_GYRO_SENSITIVITY_PP   RATE_BFP_OF_REAL( 1./1.01)
+#define NPS_GYRO_SENSITIVITY_QQ   RATE_BFP_OF_REAL(-1./1.01)
+#define NPS_GYRO_SENSITIVITY_RR   RATE_BFP_OF_REAL(-1./1.01)
 
 #define NPS_GYRO_NEUTRAL_P        33924
 #define NPS_GYRO_NEUTRAL_Q        33417
@@ -77,8 +82,8 @@
 #define NPS_GYRO_NOISE_STD_DEV_R  RadOfDeg(0.5)
 
 #define NPS_GYRO_BIAS_INITIAL_P   RadOfDeg( 0.0)
-#define NPS_GYRO_BIAS_INITIAL_Q   RadOfDeg(  .0)
-#define NPS_GYRO_BIAS_INITIAL_R   RadOfDeg(  .0)
+#define NPS_GYRO_BIAS_INITIAL_Q   RadOfDeg( 0.0)
+#define NPS_GYRO_BIAS_INITIAL_R   RadOfDeg( 0.0)
 
 #define NPS_GYRO_BIAS_RANDOM_WALK_STD_DEV_P RadOfDeg(0.)
 #define NPS_GYRO_BIAS_RANDOM_WALK_STD_DEV_Q RadOfDeg(0.)
diff --git a/sw/simulator/nps/nps_sensor_accel.c b/sw/simulator/nps/nps_sensor_accel.c
index d85329912f..65e6245d4c 100644
--- a/sw/simulator/nps/nps_sensor_accel.c
+++ b/sw/simulator/nps/nps_sensor_accel.c
@@ -1,10 +1,11 @@
 #include "nps_sensor_accel.h"
 
-#include "airframe.h"
+#include "airframe.h" /* to get NPS_SENSORS_PARAMS */
+
 #include "nps_fdm.h"
 #include "nps_random.h"
 #include NPS_SENSORS_PARAMS
-
+#include "math/pprz_algebra_int.h"
 
 void   nps_sensor_accel_init(struct NpsSensorAccel* accel, double time) {
   VECT3_ASSIGN(accel->value, 0., 0., 0.);
diff --git a/sw/simulator/nps/nps_sensor_gyro.c b/sw/simulator/nps/nps_sensor_gyro.c
index 908eb44922..86cece7471 100644
--- a/sw/simulator/nps/nps_sensor_gyro.c
+++ b/sw/simulator/nps/nps_sensor_gyro.c
@@ -3,7 +3,7 @@
 #include "airframe.h"
 #include "nps_fdm.h"
 #include NPS_SENSORS_PARAMS
-
+#include "math/pprz_algebra_int.h"
 
 void  nps_sensor_gyro_init(struct NpsSensorGyro* gyro, double time) {
   VECT3_ASSIGN(gyro->value, 0., 0., 0.);