diff --git a/EKF/CMakeLists.txt b/EKF/CMakeLists.txt
index 6400204045..9a97cf63d1 100644
--- a/EKF/CMakeLists.txt
+++ b/EKF/CMakeLists.txt
@@ -37,7 +37,7 @@ project (ECL CXX)
 set(CMAKE_BUILD_TYPE Release)
 set(CMAKE_CURRENT_SOURCE_DIR ./)
 set(CMAKE_CXX_FLAGS "-DPOSIX_SHARED")
-set (EIGEN3_INCLUDE_DIR "/usr/local/include/eigen3/")
+set(EIGEN3_INCLUDE_DIR "/usr/local/include/eigen3/")
 
 IF( NOT EIGEN3_INCLUDE_DIR )
 	MESSAGE( FATAL_ERROR "Please point the environment variable EIGEN3_INCLUDE_DIR to the include directory of your Eigen3 installation.")
@@ -69,5 +69,5 @@ set(SRCS
 	geo.cpp
 	mathlib.cpp
 )
-add_definitions(-std=c++11)
-add_library(ecl SHARED ${SRCS})
\ No newline at end of file
+add_definitions(-std=c++11 -Wall -Werror)
+add_library(ecl SHARED ${SRCS})
diff --git a/EKF/airspeed_fusion.cpp b/EKF/airspeed_fusion.cpp
index 3ec6a8e141..ae57e343c6 100644
--- a/EKF/airspeed_fusion.cpp
+++ b/EKF/airspeed_fusion.cpp
@@ -196,9 +196,6 @@ void Ekf::fuseAirspeed()
 		_state.quat_nominal.normalize();
 
 		// update covariance matrix via Pnew = (I - KH)P = P - KHP
-		float KH[_k_num_states][_k_num_states] = {};
-		float KHP[_k_num_states][_k_num_states] = {};
-
 		for (unsigned row = 0; row < _k_num_states; row++) {
 			for (unsigned column = 0; column < _k_num_states; column++) { // Here it will be a lot of zeros, should optimize that...
 				KH[row][column] = Kfusion[row] * H_TAS[column];
@@ -222,4 +219,4 @@ void Ekf::fuseAirspeed()
 		makeSymmetrical();
 		limitCov();
 	}
-}
\ No newline at end of file
+}
diff --git a/EKF/gps_checks.cpp b/EKF/gps_checks.cpp
index 47206c9d9a..45f903dfec 100644
--- a/EKF/gps_checks.cpp
+++ b/EKF/gps_checks.cpp
@@ -197,10 +197,10 @@ bool Ekf::gps_is_good(struct gps_message *gps)
 	// This check can only be used if the vehicle is stationary during alignment
 	if (!_control_status.flags.armed) {
 		vel_limit = 10.0f * _params.req_hdrift;
-		float velN = fminf(fmaxf(gps->vel_ned[0], -vel_limit), vel_limit);
-		float velE = fminf(fmaxf(gps->vel_ned[1], -vel_limit), vel_limit);
-		_gps_velN_filt = velN * filter_coef + _gps_velN_filt * (1.0f - filter_coef);
-		_gps_velE_filt  = velE * filter_coef + _gps_velE_filt  * (1.0f - filter_coef);
+		float gps_velN = fminf(fmaxf(gps->vel_ned[0], -vel_limit), vel_limit);
+		float gps_velE = fminf(fmaxf(gps->vel_ned[1], -vel_limit), vel_limit);
+		_gps_velN_filt = gps_velN * filter_coef + _gps_velN_filt * (1.0f - filter_coef);
+		_gps_velE_filt  = gps_velE * filter_coef + _gps_velE_filt  * (1.0f - filter_coef);
 		float horiz_speed = sqrtf(_gps_velN_filt * _gps_velN_filt + _gps_velE_filt * _gps_velE_filt);
 		_gps_check_fail_status.flags.hspeed = (horiz_speed > _params.req_hdrift);
 
diff --git a/EKF/vel_pos_fusion.cpp b/EKF/vel_pos_fusion.cpp
index acc430c176..75165a1cf5 100644
--- a/EKF/vel_pos_fusion.cpp
+++ b/EKF/vel_pos_fusion.cpp
@@ -246,8 +246,6 @@ void Ekf::fuseVelPosHeight()
 		_state.quat_nominal.normalize();
 
 		// update covarinace matrix via Pnew = (I - KH)P
-		float KHP[_k_num_states][_k_num_states] = {};
-
 		for (unsigned row = 0; row < _k_num_states; row++) {
 			for (unsigned column = 0; column < _k_num_states; column++) {
 				KHP[row][column] = Kfusion[row] * P[state_index][column];