Copter: set origin from last origin if none set

Author: andyp1per

ArduCopter/AP_Arming_Copter.cpp

@@ -568,7 +568,7 @@ bool AP_Arming_Copter::alt_checks(bool display_failure)
 //  has side-effect that logging is started
 bool AP_Arming_Copter::arm_checks(AP_Arming::Method method)
 {
-    const auto &ahrs = AP::ahrs();
+    auto &ahrs = AP::ahrs();
 
     // always check if inertial nav has started and is ready
     if (!ahrs.healthy()) {
@@ -647,6 +647,11 @@ bool AP_Arming_Copter::arm_checks(AP_Arming::Method method)
         return false;
     }
 
+    if (!ahrs.ensure_origin_is_set()) {
+        check_failed(true, "No origin set");
+        return false;
+    }
+
     // superclass method should always be the last thing called; it
     // has side-effects which would need to be cleaned up if one of
     // our arm checks failed