diff --git a/posix-configs/SITL/init/rc.S b/posix-configs/SITL/init/rc.S
index 271c8e3620..cc4c76526f 100644
--- a/posix-configs/SITL/init/rc.S
+++ b/posix-configs/SITL/init/rc.S
@@ -12,6 +12,7 @@ gyrosim start
 accelsim start
 barosim start
 adcsim start
+gps_sim start
 commander start
 sensors start
 ekf_att_pos_estimator start