diff --git a/libraries/AP_Avoidance/AP_Avoidance.cpp b/libraries/AP_Avoidance/AP_Avoidance.cpp
index 280381b9b7..890549a73d 100644
--- a/libraries/AP_Avoidance/AP_Avoidance.cpp
+++ b/libraries/AP_Avoidance/AP_Avoidance.cpp
@@ -252,7 +252,7 @@ void AP_Avoidance::add_obstacle(const uint32_t obstacle_timestamp_ms,
     return add_obstacle(obstacle_timestamp_ms, src, src_id, loc, vel);
 }
 
-uint32_t AP_Avoidance::src_id_for_adsb_vehicle(AP_ADSB::adsb_vehicle_t vehicle) const
+uint32_t AP_Avoidance::src_id_for_adsb_vehicle(const AP_ADSB::adsb_vehicle_t &vehicle) const
 {
     // TODO: need to include squawk code and callsign
     return vehicle.info.ICAO_address;
diff --git a/libraries/AP_Avoidance/AP_Avoidance.h b/libraries/AP_Avoidance/AP_Avoidance.h
index 6fd47239cc..df535d0d3f 100644
--- a/libraries/AP_Avoidance/AP_Avoidance.h
+++ b/libraries/AP_Avoidance/AP_Avoidance.h
@@ -156,7 +156,7 @@ private:
     void deinit();
 
     // get unique id for adsb
-    uint32_t src_id_for_adsb_vehicle(AP_ADSB::adsb_vehicle_t vehicle) const;
+    uint32_t src_id_for_adsb_vehicle(const AP_ADSB::adsb_vehicle_t &vehicle) const;
 
     void check_for_threats();
     void update_threat_level(const Location &my_loc,