diff --git a/src/flight_imu.c b/src/flight_imu.c
index c5b6904ff..09f415a97 100644
--- a/src/flight_imu.c
+++ b/src/flight_imu.c
@@ -44,7 +44,6 @@ float accVelScale;
 
 int16_t smallAngle = 0;
 
-int32_t sonarAlt;              // to think about the unit
 int32_t EstAlt;                // in cm
 int32_t AltHold;
 int32_t errorAltitudeI = 0;
diff --git a/src/sensors_sonar.c b/src/sensors_sonar.c
index fbee59e1f..6e6d481bc 100644
--- a/src/sensors_sonar.c
+++ b/src/sensors_sonar.c
@@ -1,5 +1,15 @@
-#include "board.h"
-#include "mw.h"
+#include <stdbool.h>
+#include <stdint.h>
+
+#include "platform.h"
+
+#include "drivers/sonar_hcsr04.h"
+#include "runtime_config.h"
+
+#include "sensors_common.h"
+#include "sensors_sonar.h"
+
+int32_t sonarAlt;              // to think about the unit
 
 #ifdef SONAR