diff --git a/EKF/ekf.h b/EKF/ekf.h
index 25fb0f0138..f657382916 100644
--- a/EKF/ekf.h
+++ b/EKF/ekf.h
@@ -98,7 +98,7 @@ public:
 private:
 
 	static const uint8_t _k_num_states = 24;
-	static const float _k_earth_rate = 0.000072921f;
+	static constexpr float _k_earth_rate = 0.000072921f;
 
 	stateSample _state;		// state struct of the ekf running at the delayed time horizon