diff --git a/libraries/AP_HAL_SITL/sitl_ins.cpp b/libraries/AP_HAL_SITL/sitl_ins.cpp
index f76ef3d127..2a6383ef4a 100644
--- a/libraries/AP_HAL_SITL/sitl_ins.cpp
+++ b/libraries/AP_HAL_SITL/sitl_ins.cpp
@@ -103,8 +103,8 @@ uint16_t SITL_State::_ground_sonar(void)
     }
 
     float voltage = 5.0f;
-    if (fabsf(_sitl->state.rollDeg) < 90 &&
-            fabsf(_sitl->state.pitchDeg) < 90) {
+    if (fabs(_sitl->state.rollDeg) < 90 &&
+        fabs(_sitl->state.pitchDeg) < 90) {
         // adjust for apparent altitude with roll
         altitude /= cosf(radians(_sitl->state.rollDeg)) * cosf(radians(_sitl->state.pitchDeg));