diff --git a/src/examples/flow_position_estimator/flow_position_estimator_main.c b/src/examples/flow_position_estimator/flow_position_estimator_main.c
index 0b8c01f798..8cc9ed6862 100644
--- a/src/examples/flow_position_estimator/flow_position_estimator_main.c
+++ b/src/examples/flow_position_estimator/flow_position_estimator_main.c
@@ -67,6 +67,7 @@
 #include <systemlib/perf_counter.h>
 #include <systemlib/systemlib.h>
 #include <poll.h>
+#include <px4_defines.h>
 
 #include "flow_position_estimator_params.h"
 
@@ -337,7 +338,7 @@ int flow_position_estimator_thread_main(int argc, char *argv[])
 						{
 							float sum = 0.0f;
 							for(uint8_t j = 0; j < 3; j++)
-								sum = sum + speed[j] * att.R[i][j];
+								sum = sum + speed[j] * PX4_R(att.R, i, j);
 
 							global_speed[i] = sum;
 						}
diff --git a/src/include/px4.h b/src/include/px4.h
index 22d661b17c..45068a6f77 100644
--- a/src/include/px4.h
+++ b/src/include/px4.h
@@ -59,7 +59,7 @@
 
 #endif
 
-#include "../platforms/px4_defines.h"
+#include <px4_defines.h>
 #include "../platforms/px4_middleware.h"
 #include "../platforms/px4_nodehandle.h"
 #include "../platforms/px4_subscriber.h"
diff --git a/src/platforms/px4_defines.h b/src/include/px4_defines.h
similarity index 94%
rename from src/platforms/px4_defines.h
rename to src/include/px4_defines.h
index 84e5c8da09..2dd57940d1 100644
--- a/src/platforms/px4_defines.h
+++ b/src/include/px4_defines.h
@@ -51,7 +51,6 @@
 #define PX4_TOPIC_T(_name) _name
 #define PX4_SUBSCRIBE_CBMETH(_nodehandle, _name, _cbf, _obj, _interval) _nodehandle.subscribe(PX4_TOPIC(_name), &_cbf, &_obj);
 #define PX4_SUBSCRIBE_CBFUNC(_nodehandle, _name, _cbf, _interval) _nodehandle.subscribe(PX4_TOPIC(_name), _cbf);
-
 #else
 /*
  * Building for NuttX
@@ -70,3 +69,9 @@
 #define PX4_GET_SUBSCRIBE(_1, _2, _3, _4, _5, NAME, ...) NAME
 #define PX4_SUBSCRIBE(...) PX4_GET_SUBSCRIBE(__VA_ARGS__, PX4_SUBSCRIBE_CBMETH, PX4_SUBSCRIBE_CBFUNC)(__VA_ARGS__)
 #define PX4_ADVERTISE(_nodehandle, _name) _nodehandle.advertise<PX4_TOPIC_T(_name)>(PX4_TOPIC(_name))
+
+/* wrapper for 2d matrices */
+#define PX4_ARRAY2D(_array, _ncols, _x, _y) (_array[_x * _ncols + _y])
+
+/* wrapper for rotation matrices stored in arrays */
+#define PX4_R(_array, _x, _y) PX4_ARRAY2D(_array, 3, _x, _y)