diff --git a/src/lib/matrix/matrix/Quaternion.hpp b/src/lib/matrix/matrix/Quaternion.hpp
index 5b91dde0a4..7155bdff1a 100644
--- a/src/lib/matrix/matrix/Quaternion.hpp
+++ b/src/lib/matrix/matrix/Quaternion.hpp
@@ -458,7 +458,7 @@ public:
 
 		for (size_t i = 0; i < 4; i++) {
 			if (std::fabs(q(i)) > FLT_EPSILON) {
-				return q * Type(matrix::sign(q(i)));
+				return q * Type(sign(q(i)));
 			}
 		}
 
diff --git a/src/lib/matrix/matrix/helper_functions.hpp b/src/lib/matrix/matrix/helper_functions.hpp
index 6a9e871ef0..08e74d7115 100644
--- a/src/lib/matrix/matrix/helper_functions.hpp
+++ b/src/lib/matrix/matrix/helper_functions.hpp
@@ -2,6 +2,8 @@
 
 #include <cmath>
 
+#include "math.hpp"
+
 namespace matrix
 {
 
@@ -41,7 +43,7 @@ Floating wrap_floating(Floating x, Floating low, Floating high)
 	return x - range * num_wraps;
 }
 
-}  // namespace detail
+} // namespace detail
 
 /**
  * Wrap single precision floating point value to stay in range [low, high)
diff --git a/src/modules/flight_mode_manager/tasks/AutoFollowTarget/FlightTaskAutoFollowTarget.hpp b/src/modules/flight_mode_manager/tasks/AutoFollowTarget/FlightTaskAutoFollowTarget.hpp
index 23f4fdd0b7..1eb4ba8557 100644
--- a/src/modules/flight_mode_manager/tasks/AutoFollowTarget/FlightTaskAutoFollowTarget.hpp
+++ b/src/modules/flight_mode_manager/tasks/AutoFollowTarget/FlightTaskAutoFollowTarget.hpp
@@ -57,7 +57,6 @@
 #include <uORB/topics/vehicle_command.h>
 
 #include <lib/mathlib/math/filter/second_order_reference_model.hpp>
-#include <lib/matrix/matrix/helper_functions.hpp>
 #include <motion_planning/VelocitySmoothing.hpp>
 
 // << Follow Target Behavior related constants >>