diff --git a/libraries/AP_VisualOdom/AP_VisualOdom_Backend.cpp b/libraries/AP_VisualOdom/AP_VisualOdom_Backend.cpp
index b0974348e1..5519f86d45 100644
--- a/libraries/AP_VisualOdom/AP_VisualOdom_Backend.cpp
+++ b/libraries/AP_VisualOdom/AP_VisualOdom_Backend.cpp
@@ -36,6 +36,7 @@ bool AP_VisualOdom_Backend::healthy() const
     return ((AP_HAL::millis() - _last_update_ms) < AP_VISUALODOM_TIMEOUT_MS);
 }
 
+#if HAL_GCS_ENABLED
 // consume vision_position_delta mavlink messages
 void AP_VisualOdom_Backend::handle_vision_position_delta_msg(const mavlink_message_t &msg)
 {
@@ -69,6 +70,7 @@ void AP_VisualOdom_Backend::handle_vision_position_delta_msg(const mavlink_messa
                                   position_delta,
                                   packet.confidence);
 }
+#endif  // HAL_GCS_ENABLED
 
 // returns the system time of the last reset if reset_counter has not changed
 // updates the reset timestamp to the current system time if the reset_counter has changed
diff --git a/libraries/AP_VisualOdom/AP_VisualOdom_Backend.h b/libraries/AP_VisualOdom/AP_VisualOdom_Backend.h
index b17eef76e7..ce2033ca4c 100644
--- a/libraries/AP_VisualOdom/AP_VisualOdom_Backend.h
+++ b/libraries/AP_VisualOdom/AP_VisualOdom_Backend.h
@@ -27,8 +27,10 @@ public:
     // return true if sensor is basically healthy (we are receiving data)
     bool healthy() const;
 
+#if HAL_GCS_ENABLED
     // consume vision_position_delta mavlink messages
     void handle_vision_position_delta_msg(const mavlink_message_t &msg);
+#endif
 
     // consume vision pose estimate data and send to EKF. distances in meters
     virtual void handle_pose_estimate(uint64_t remote_time_us, uint32_t time_ms, float x, float y, float z, const Quaternion &attitude, float posErr, float angErr, uint8_t reset_counter) = 0;