diff --git a/Tools/AntennaTracker/AntennaTracker.pde b/Tools/AntennaTracker/AntennaTracker.pde
index 3804d6257c..671df4c383 100644
--- a/Tools/AntennaTracker/AntennaTracker.pde
+++ b/Tools/AntennaTracker/AntennaTracker.pde
@@ -54,6 +54,7 @@
 
 #include <AP_Vehicle.h>
 #include <AP_Mission.h>
+#include <AP_Terrain.h>
 #include <AP_Notify.h>      // Notify library
 #include <AP_BattMonitor.h> // Battery monitor library
 #include <AP_Airspeed.h>