diff --git a/conf/airframes/easystar_ets_example.xml b/conf/airframes/easystar_ets_example.xml
index 3e6f1e5548..763be2683d 100644
--- a/conf/airframes/easystar_ets_example.xml
+++ b/conf/airframes/easystar_ets_example.xml
@@ -19,6 +19,7 @@
     <define name="ALT_KALMAN"/>
     <define name="USE_I2C0"/>
     <define name="USE_AIRSPEED"/>
+    <define name="USE_BARO_ETS"/>
 
     <subsystem name="radio_control" type="ppm"/>
     <subsystem name="telemetry"     type="transparent"/>
diff --git a/sw/airborne/gps.h b/sw/airborne/gps.h
index b6c28317b8..e201bc4980 100644
--- a/sw/airborne/gps.h
+++ b/sw/airborne/gps.h
@@ -56,7 +56,7 @@ extern uint8_t gps_status_flags;
 extern uint8_t gps_sol_flags;
 extern uint16_t gps_week;    /* weeks */
 extern uint32_t gps_itow;    /* ms */
-extern int32_t  gps_alt;    /* cm       */
+extern int32_t  gps_alt;    /* above MSL in cm       */
 extern uint16_t gps_speed_3d;  /* cm/s     */
 extern uint16_t gps_gspeed;  /* cm/s     */
 extern int16_t  gps_climb;  /* m/s     */