diff --git a/libraries/AP_Math/AP_Math.cpp b/libraries/AP_Math/AP_Math.cpp
index 646fab728f..04476a3b96 100644
--- a/libraries/AP_Math/AP_Math.cpp
+++ b/libraries/AP_Math/AP_Math.cpp
@@ -25,7 +25,7 @@ template <typename Arithmetic1, typename Arithmetic2>
 typename std::enable_if<std::is_floating_point<typename std::common_type<Arithmetic1, Arithmetic2>::type>::value, bool>::type
 is_equal(const Arithmetic1 v_1, const Arithmetic2 v_2)
 {
-#ifdef ALLOW_DOUBLE_MATH_FUNCTIONS
+#if AP_MATH_ALLOW_DOUBLE_FUNCTIONS
     typedef typename std::common_type<Arithmetic1, Arithmetic2>::type common_type;
     typedef typename std::remove_cv<common_type>::type common_type_nonconst;
     if (std::is_same<double, common_type_nonconst>::value) {
@@ -169,7 +169,7 @@ T wrap_180_cd(const T angle)
 template int wrap_180<int>(const int angle);
 template short wrap_180<short>(const short angle);
 template float wrap_180<float>(const float angle);
-#ifdef ALLOW_DOUBLE_MATH_FUNCTIONS
+#if AP_MATH_ALLOW_DOUBLE_FUNCTIONS
 template double wrap_180<double>(const double angle);
 #endif
 
@@ -177,7 +177,7 @@ template int wrap_180_cd<int>(const int angle);
 template long wrap_180_cd<long>(const long angle);
 template short wrap_180_cd<short>(const short angle);
 template float wrap_180_cd<float>(const float angle);
-#ifdef ALLOW_DOUBLE_MATH_FUNCTIONS
+#if AP_MATH_ALLOW_DOUBLE_FUNCTIONS
 template double wrap_180_cd<double>(const double angle);
 #endif
 
@@ -190,7 +190,7 @@ float wrap_360(const float angle)
     return res;
 }
 
-#ifdef ALLOW_DOUBLE_MATH_FUNCTIONS
+#if AP_MATH_ALLOW_DOUBLE_FUNCTIONS
 double wrap_360(const double angle)
 {
     double res = fmod(angle, 360.0);
@@ -219,7 +219,7 @@ float wrap_360_cd(const float angle)
     return res;
 }
 
-#ifdef ALLOW_DOUBLE_MATH_FUNCTIONS
+#if AP_MATH_ALLOW_DOUBLE_FUNCTIONS
 double wrap_360_cd(const double angle)
 {
     double res = fmod(angle, 36000.0);
diff --git a/libraries/AP_Math/AP_Math.h b/libraries/AP_Math/AP_Math.h
index 2a1984b0d7..fa54d18bb2 100644
--- a/libraries/AP_Math/AP_Math.h
+++ b/libraries/AP_Math/AP_Math.h
@@ -141,7 +141,7 @@ T wrap_180_cd(const T angle);
  * 100 == centi.
  */
 float wrap_360(const float angle);
-#ifdef ALLOW_DOUBLE_MATH_FUNCTIONS
+#if AP_MATH_ALLOW_DOUBLE_FUNCTIONS
 double wrap_360(const double angle);
 #endif
 int wrap_360(const int angle);
@@ -149,7 +149,7 @@ int wrap_360(const int angle);
 int wrap_360_cd(const int angle);
 long wrap_360_cd(const long angle);
 float wrap_360_cd(const float angle);
-#ifdef ALLOW_DOUBLE_MATH_FUNCTIONS
+#if AP_MATH_ALLOW_DOUBLE_FUNCTIONS
 double wrap_360_cd(const double angle);
 #endif
 
diff --git a/libraries/AP_Math/definitions.h b/libraries/AP_Math/definitions.h
index 5f2b8bc75d..f8a4a5c4f8 100644
--- a/libraries/AP_Math/definitions.h
+++ b/libraries/AP_Math/definitions.h
@@ -3,6 +3,7 @@
 #include <cmath>
 
 #include <AP_HAL/AP_HAL_Boards.h>
+#include <AP_HAL/AP_HAL_Macros.h>  // sets AP_MATH_ALLOW_DOUBLE_FUNCTIONS
 
 #ifdef M_PI
 # undef M_PI
@@ -35,7 +36,7 @@
 // GPS Specific double precision conversions
 // The precision here does matter when using the wsg* functions for converting
 // between LLH and ECEF coordinates.
-#ifdef ALLOW_DOUBLE_MATH_FUNCTIONS
+#if AP_MATH_ALLOW_DOUBLE_FUNCTIONS
 static const double DEG_TO_RAD_DOUBLE = asin(1) / 90;
 static const double RAD_TO_DEG_DOUBLE = 1 / DEG_TO_RAD_DOUBLE;
 #endif
@@ -65,7 +66,7 @@ static const double WGS84_F = ((double)1.0 / WGS84_IF);
 static const double WGS84_B = (WGS84_A * (1 - WGS84_F));
 
 // Eccentricity of the Earth
-#ifdef ALLOW_DOUBLE_MATH_FUNCTIONS
+#if AP_MATH_ALLOW_DOUBLE_FUNCTIONS
 static const double WGS84_E = (sqrt(2 * WGS84_F - WGS84_F * WGS84_F));
 #endif
 
diff --git a/libraries/AP_Math/examples/location/location.cpp b/libraries/AP_Math/examples/location/location.cpp
index 414bece40f..c485626270 100644
--- a/libraries/AP_Math/examples/location/location.cpp
+++ b/libraries/AP_Math/examples/location/location.cpp
@@ -2,7 +2,7 @@
 // Unit tests for the AP_Math polygon code
 //
 
-#define ALLOW_DOUBLE_MATH_FUNCTIONS
+#define AP_MATH_ALLOW_DOUBLE_FUNCTIONS 1
 
 #include <AP_HAL/AP_HAL.h>
 #include <AP_Math/AP_Math.h>
diff --git a/libraries/AP_Math/ftype.h b/libraries/AP_Math/ftype.h
index 4f5f436a3b..0fac8cad3e 100644
--- a/libraries/AP_Math/ftype.h
+++ b/libraries/AP_Math/ftype.h
@@ -68,7 +68,7 @@ inline bool is_zero(const float x) {
  * @brief: Check whether a double is zero
  */
 inline bool is_zero(const double x) {
-#ifdef ALLOW_DOUBLE_MATH_FUNCTIONS
+#if AP_MATH_ALLOW_DOUBLE_FUNCTIONS
   return fabs(x) < FLT_EPSILON;
 #else
   return fabsf(static_cast<float>(x)) < FLT_EPSILON;
diff --git a/libraries/AP_Math/location_double.cpp b/libraries/AP_Math/location_double.cpp
index a6d24dc1b8..e894435c03 100644
--- a/libraries/AP_Math/location_double.cpp
+++ b/libraries/AP_Math/location_double.cpp
@@ -19,7 +19,7 @@
   this is for double precision functions related to the location structure
  */
 
-#define ALLOW_DOUBLE_MATH_FUNCTIONS
+#define AP_MATH_ALLOW_DOUBLE_FUNCTIONS 1
 
 #include <AP_HAL/AP_HAL.h>
 #include <stdlib.h>