diff --git a/libraries/AP_Math/AP_Math.cpp b/libraries/AP_Math/AP_Math.cpp
index dcfd788b22..e553ade4d9 100644
--- a/libraries/AP_Math/AP_Math.cpp
+++ b/libraries/AP_Math/AP_Math.cpp
@@ -339,13 +339,13 @@ uint16_t get_random16(void)
 }
 
 
-// generate a random float between -1 and 1, for use in SITL
+// generate a random float between -1 and 1
 float rand_float(void)
 {
 #if CONFIG_HAL_BOARD == HAL_BOARD_SITL
     return ((((unsigned)random()) % 2000000) - 1.0e6) / 1.0e6;
 #else
-    return get_random16() / 65535.0;
+    return (get_random16() / 65535.0) * 2 - 1;
 #endif
 }