diff --git a/libraries/AP_Terrain/TerrainMission.cpp b/libraries/AP_Terrain/TerrainMission.cpp
index 3ad69e3c90..656f15574f 100644
--- a/libraries/AP_Terrain/TerrainMission.cpp
+++ b/libraries/AP_Terrain/TerrainMission.cpp
@@ -23,6 +23,7 @@
 #include <GCS_MAVLink/GCS_MAVLink.h>
 #include <GCS_MAVLink/GCS.h>
 #include "AP_Terrain.h"
+#include <AP_GPS/AP_GPS.h>
 
 #if AP_TERRAIN_AVAILABLE