diff --git a/corsika/detail/framework/geometry/CoordinateSystem.inl b/corsika/detail/framework/geometry/CoordinateSystem.inl
index 608c33da816c61b42b0a3eb6ecfb41dfa7b6c336..4ec390bd2900887257b0c2a52caabfcb2c85bc4f 100644
--- a/corsika/detail/framework/geometry/CoordinateSystem.inl
+++ b/corsika/detail/framework/geometry/CoordinateSystem.inl
@@ -14,7 +14,6 @@
 #include <Eigen/Dense>
 #include <stdexcept>
 #include <corsika/framework/core/PhysicalUnits.hpp>
-#include <corsika/framework/utility/sgn.hpp>
 
 
 namespace corsika {
@@ -38,14 +37,12 @@ namespace corsika {
     auto CoordinateSystem::RotateToZ(Vector<TDim> vVec) const
     {
       auto const a = vVec.normalized().GetComponents(*this).eVector;
-      auto const a1 = a(0), a2 = a(1);
-
-      auto const s = corsika::sgn(a(2));
-      auto const c = 1 / (1 + s * a(2));
+      auto const a1 = a(0), a2 = a(1), a3 = a(2);
 
       Eigen::Matrix3d A, B;
 
-      if (s > 0) {
+      if (a3 > 0) {
+        auto const c = 1 / (1 + a3);
         A << 1, 0, -a1,                     // comment to prevent clang-format
             0, 1, -a2,                      // .
             a1, a2, 1;                      // .
@@ -54,6 +51,7 @@ namespace corsika {
             0, 0, -(a1 * a1 + a2 * a2) * c; // .
 
       } else {
+        auto const c = 1 / (1 - a3);
         A << 1, 0, a1,                      // .
             0, -1, -a2,                     // .
             a1, a2, -1;                     // .
diff --git a/corsika/detail/framework/utility/COMBoost.inl b/corsika/detail/framework/utility/COMBoost.inl
index 352ee4e6c8eee3d7088a2ec0390aa64b16249380..338114b9ff260230cee8bdc786d739d48ddf6dac 100644
--- a/corsika/detail/framework/utility/COMBoost.inl
+++ b/corsika/detail/framework/utility/COMBoost.inl
@@ -18,7 +18,6 @@
 #include <corsika/framework/geometry/FourVector.hpp>
 #include <corsika/framework/geometry/Vector.hpp>
 #include <corsika/framework/logging/Logging.h>
-#include <corsika/framework/utility/sgn.hpp>
 
 // using namespace corsika::units::si;
 
diff --git a/corsika/framework/geometry/CoordinateSystem.hpp b/corsika/framework/geometry/CoordinateSystem.hpp
index 901968cf44ed48a7fc7ed89a0c0833e8067f89d2..9b6b6ac0297f95f55fb30f44da76c8419a1c439f 100644
--- a/corsika/framework/geometry/CoordinateSystem.hpp
+++ b/corsika/framework/geometry/CoordinateSystem.hpp
@@ -10,7 +10,6 @@ n/*
 
 #include <corsika/framework/core/PhysicalUnits.hpp>
 #include <corsika/framework/geometry/QuantityVector.hpp>
-#include <corsika/framework/utility/sgn.hpp>
 
 #include <Eigen/Dense>
 #include <stdexcept>