AP_NavEKF3: pre_arm_check may skip position checks

libraries/AP_NavEKF3/AP_NavEKF3.cpp

@@ -1060,10 +1060,11 @@ bool NavEKF3::healthy(void) const
 }
 
 // returns false if we fail arming checks, in which case the buffer will be populated with a failure message
-bool NavEKF3::pre_arm_check(char *failure_msg, uint8_t failure_msg_len) const
+// requires_position should be true if horizontal position configuration should be checked
+bool NavEKF3::pre_arm_check(bool requires_position, char *failure_msg, uint8_t failure_msg_len) const
 {
     // check source configuration
-    if (!sources.pre_arm_check(failure_msg, failure_msg_len)) {
+    if (!sources.pre_arm_check(requires_position, failure_msg, failure_msg_len)) {
         return false;
     }
 

libraries/AP_NavEKF3/AP_NavEKF3.h

@@ -56,7 +56,8 @@ public:
     bool healthy(void) const;
 
     // returns false if we fail arming checks, in which case the buffer will be populated with a failure message
-    bool pre_arm_check(char *failure_msg, uint8_t failure_msg_len) const;
+    // requires_position should be true if horizontal position configuration should be checked
+    bool pre_arm_check(bool requires_position, char *failure_msg, uint8_t failure_msg_len) const;
 
     // returns the index of the primary core
     // return -1 if no primary core selected