diff --git a/libraries/AC_PrecLand/AC_PrecLand_Backend.h b/libraries/AC_PrecLand/AC_PrecLand_Backend.h
index ae748951fe..0d447ce7e2 100644
--- a/libraries/AC_PrecLand/AC_PrecLand_Backend.h
+++ b/libraries/AC_PrecLand/AC_PrecLand_Backend.h
@@ -31,7 +31,7 @@ public:
     //  returns true if angles are available, false if not (i.e. no target)
     //  x_angle_rad : body-frame roll direction, positive = target is to right (looking down)
     //  y_angle_rad : body-frame pitch direction, postiive = target is forward (looking down)
-    virtual bool get_angle_to_target(float &x_angle_rad, float &y_angle_rad) const = 0;
+    virtual bool get_angle_to_target(float &x_angle_rad, float &y_angle_rad) = 0;
 
 protected:
 
diff --git a/libraries/AC_PrecLand/AC_PrecLand_IRLock.cpp b/libraries/AC_PrecLand/AC_PrecLand_IRLock.cpp
index 21d18463d5..9666aa44cf 100644
--- a/libraries/AC_PrecLand/AC_PrecLand_IRLock.cpp
+++ b/libraries/AC_PrecLand/AC_PrecLand_IRLock.cpp
@@ -34,7 +34,7 @@ bool AC_PrecLand_IRLock::update()
 //  returns true if angles are available, false if not (i.e. no target)
 //  x_angle_rad : body-frame roll direction, positive = target is to right (looking down)
 //  y_angle_rad : body-frame pitch direction, postiive = target is forward (looking down)
-bool AC_PrecLand_IRLock::get_angle_to_target(float &x_angle_rad, float &y_angle_rad) const
+bool AC_PrecLand_IRLock::get_angle_to_target(float &x_angle_rad, float &y_angle_rad)
 {
     return irlock.get_angle_to_target(x_angle_rad, y_angle_rad);
 }
diff --git a/libraries/AC_PrecLand/AC_PrecLand_IRLock.h b/libraries/AC_PrecLand/AC_PrecLand_IRLock.h
index 35245b808e..381cf0b90f 100644
--- a/libraries/AC_PrecLand/AC_PrecLand_IRLock.h
+++ b/libraries/AC_PrecLand/AC_PrecLand_IRLock.h
@@ -33,7 +33,7 @@ public:
     //  returns true if angles are available, false if not (i.e. no target)
     //  x_angle_rad : body-frame roll direction, positive = target is to right (looking down)
     //  y_angle_rad : body-frame pitch direction, postiive = target is forward (looking down)
-    bool get_angle_to_target(float &x_angle_rad, float &y_angle_rad) const;
+    bool get_angle_to_target(float &x_angle_rad, float &y_angle_rad);
 
 private:
     AP_IRLock_PX4 irlock;