diff --git a/libraries/AC_Avoidance/AP_OAPathPlanner.cpp b/libraries/AC_Avoidance/AP_OAPathPlanner.cpp
index 5e2b0f7e6c..d513d49756 100644
--- a/libraries/AC_Avoidance/AP_OAPathPlanner.cpp
+++ b/libraries/AC_Avoidance/AP_OAPathPlanner.cpp
@@ -24,11 +24,11 @@
 extern const AP_HAL::HAL &hal;
 
 // parameter defaults
-const float OA_MARGIN_MAX_DEFAULT = 5;
-const int16_t OA_OPTIONS_DEFAULT = 1;
+static constexpr float OA_MARGIN_MAX_DEFAULT = 5;
+static constexpr int16_t OA_OPTIONS_DEFAULT = 1;
 
-const int16_t OA_UPDATE_MS = 1000;      // path planning updates run at 1hz
-const int16_t OA_TIMEOUT_MS = 3000;     // results over 3 seconds old are ignored
+static constexpr int16_t OA_UPDATE_MS = 1000;      // path planning updates run at 1hz
+static constexpr int16_t OA_TIMEOUT_MS = 3000;     // results over 3 seconds old are ignored
 
 const AP_Param::GroupInfo AP_OAPathPlanner::var_info[] = {