diff --git a/Tools/ardupilotwaf/boards.py b/Tools/ardupilotwaf/boards.py
index 2ca6e13286..df4b5f9be7 100644
--- a/Tools/ardupilotwaf/boards.py
+++ b/Tools/ardupilotwaf/boards.py
@@ -359,7 +359,13 @@ class Board:
             for f in os.listdir('libraries/AP_OSD/fonts'):
                 if fnmatch.fnmatch(f, "font*bin"):
                     env.ROMFS_FILES += [(f,'libraries/AP_OSD/fonts/'+f)]
-            
+
+        if cfg.options.ekf_double:
+            env.CXXFLAGS += ['-DHAL_EKF_DOUBLE=1']
+
+        if cfg.options.ekf_single:
+            env.CXXFLAGS += ['-DHAL_EKF_DOUBLE=0']
+
     def pre_build(self, bld):
         '''pre-build hook that gets called before dynamic sources'''
         if bld.env.ROMFS_FILES:
diff --git a/wscript b/wscript
index ee95965666..a76f269d91 100644
--- a/wscript
+++ b/wscript
@@ -255,6 +255,16 @@ configuration in order to save typing.
         action='store_true',
         default=False,
         help='Configure without EKF3.')
+
+    g.add_option('--ekf-double',
+        action='store_true',
+        default=False,
+        help='Configure EKF as double precision.')
+
+    g.add_option('--ekf-single',
+        action='store_true',
+        default=False,
+        help='Configure EKF as single precision.')
     
     g.add_option('--static',
         action='store_true',