diff --git a/libraries/AP_L1_Control/AP_L1_Control.cpp b/libraries/AP_L1_Control/AP_L1_Control.cpp
index 9297d7d24a..567b04efe1 100644
--- a/libraries/AP_L1_Control/AP_L1_Control.cpp
+++ b/libraries/AP_L1_Control/AP_L1_Control.cpp
@@ -53,7 +53,7 @@ const AP_Param::GroupInfo AP_L1_Control::var_info[] = {
 /*
   Wrap AHRS yaw if in reverse - radians
  */
-float AP_L1_Control::get_yaw()
+float AP_L1_Control::get_yaw() const
 {
     if (_reverse) {
         return wrap_PI(M_PI + _ahrs.yaw);
diff --git a/libraries/AP_L1_Control/AP_L1_Control.h b/libraries/AP_L1_Control/AP_L1_Control.h
index 458fe98b2b..ca57823f52 100644
--- a/libraries/AP_L1_Control/AP_L1_Control.h
+++ b/libraries/AP_L1_Control/AP_L1_Control.h
@@ -127,6 +127,6 @@ private:
     AP_Float _loiter_bank_limit;
 
     bool _reverse = false;
-    float get_yaw();
+    float get_yaw() const;
     int32_t get_yaw_sensor() const;
 };