diff --git a/libraries/AP_Compass/AP_Compass_Backend.h b/libraries/AP_Compass/AP_Compass_Backend.h
index a1cafdf292..5193a83f7c 100644
--- a/libraries/AP_Compass/AP_Compass_Backend.h
+++ b/libraries/AP_Compass/AP_Compass_Backend.h
@@ -61,8 +61,9 @@ public:
         DEVTYPE_IST8310 = 0x0A,
         DEVTYPE_ICM20948 = 0x0B,
         DEVTYPE_MMC3416 = 0x0C,
-	DEVTYPE_QMC5883L = 0x0D,
-	DEVTYPE_MAG3110  = 0x0E,
+        DEVTYPE_QMC5883L = 0x0D,
+        DEVTYPE_MAG3110  = 0x0E,
+        DEVTYPE_SITL  = 0x0F,
     };
 
 
diff --git a/libraries/AP_Compass/AP_Compass_SITL.cpp b/libraries/AP_Compass/AP_Compass_SITL.cpp
index f8a0e4d2f9..a2dfe7c089 100644
--- a/libraries/AP_Compass/AP_Compass_SITL.cpp
+++ b/libraries/AP_Compass/AP_Compass_SITL.cpp
@@ -14,6 +14,7 @@ AP_Compass_SITL::AP_Compass_SITL(Compass &compass):
         _compass._setup_earth_field();
         for (uint8_t i=0; i<SITL_NUM_COMPASSES; i++) {
             _compass_instance[i] = register_compass();
+            set_dev_id(_compass_instance[i], AP_HAL::Device::make_bus_id(AP_HAL::Device::BUS_TYPE_SITL, i, 0, DEVTYPE_SITL));
         }
         hal.scheduler->register_timer_process(FUNCTOR_BIND(this, &AP_Compass_SITL::_timer, void));
     }