From c8e0ae6890d230b2100999515dfeaf74d5b3ec8d Mon Sep 17 00:00:00 2001
From: Peter Barker <pbarker@barker.dropbear.id.au>
Date: Wed, 27 Dec 2017 20:10:08 +1100
Subject: [PATCH] AC_Fence: adjust fence sys_status failed based on position
 and parameters

---
 libraries/AC_Fence/AC_Fence.cpp | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/libraries/AC_Fence/AC_Fence.cpp b/libraries/AC_Fence/AC_Fence.cpp
index f19035089d..66e47881e4 100644
--- a/libraries/AC_Fence/AC_Fence.cpp
+++ b/libraries/AC_Fence/AC_Fence.cpp
@@ -588,6 +588,24 @@ bool AC_Fence::sys_status_failed() const
             return true;
         }
     }
+    if (_enabled_fences & AC_FENCE_TYPE_CIRCLE) {
+        if (_circle_radius < 0) {
+            return true;
+        }
+    }
+    if (_enabled_fences & AC_FENCE_TYPE_ALT_MAX) {
+        if (_alt_max < 0.0f) {
+            return true;
+        }
+    }
+    if ((_enabled_fences & AC_FENCE_TYPE_CIRCLE) ||
+        (_enabled_fences & AC_FENCE_TYPE_POLYGON)) {
+        Vector2f position;
+        if (!_ahrs.get_relative_position_NE_home(position)) {
+            // both these fence types require position
+            return true;
+        }
+    }
 
     return false;
 }