diff --git a/sw/airborne/boards/ardrone/navdata.c b/sw/airborne/boards/ardrone/navdata.c
index 7d0e185dcb..639663ba9f 100644
--- a/sw/airborne/boards/ardrone/navdata.c
+++ b/sw/airborne/boards/ardrone/navdata.c
@@ -36,7 +36,17 @@
 #include <math.h>
 #include "navdata.h"
 
-int nav_fd;
+typedef struct {
+	uint8_t isInitialized;
+	uint8_t isOpen;
+	uint16_t bytesRead;
+	uint32_t totalBytesRead;
+	uint32_t packetsRead;
+	uint8_t buffer[NAVDATA_BUFFER_SIZE];
+} navdata_port;
+
+static navdata_port* port;
+static int nav_fd;
 
 int navdata_init()
 {
diff --git a/sw/airborne/boards/ardrone/navdata.h b/sw/airborne/boards/ardrone/navdata.h
index 922bb2e46b..758f30a151 100644
--- a/sw/airborne/boards/ardrone/navdata.h
+++ b/sw/airborne/boards/ardrone/navdata.h
@@ -36,15 +36,6 @@
 #define NAVDATA_BUFFER_SIZE 80
 #define NAVDATA_START_BYTE 0x3a
 
-typedef struct {
-	uint8_t isInitialized;
-	uint8_t isOpen;
-	uint16_t bytesRead;
-	uint32_t totalBytesRead;
-	uint32_t packetsRead;
-	uint8_t buffer[NAVDATA_BUFFER_SIZE];
-} navdata_port;
-
 typedef struct
 {
   uint16_t taille;
@@ -109,7 +100,6 @@ struct bmp180_baro_calibration
 
 measures_t* navdata;
 struct bmp180_baro_calibration baro_calibration;
-navdata_port* port;
 uint16_t navdata_cks;
 uint8_t navdata_imu_available;
 uint8_t navdata_baro_available;