From 62932f884fa4352a31d6ec244db2d4523aede240 Mon Sep 17 00:00:00 2001
From: Randy Mackay <rmackay9@yahoo.com>
Date: Thu, 21 Jan 2021 12:42:19 +0900
Subject: [PATCH] AP_AHRS: pre_arm_check may skip position checks

---
 libraries/AP_AHRS/AP_AHRS.h          | 3 ++-
 libraries/AP_AHRS/AP_AHRS_DCM.cpp    | 3 ++-
 libraries/AP_AHRS/AP_AHRS_DCM.h      | 3 ++-
 libraries/AP_AHRS/AP_AHRS_NavEKF.cpp | 5 +++--
 libraries/AP_AHRS/AP_AHRS_NavEKF.h   | 3 ++-
 5 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/libraries/AP_AHRS/AP_AHRS.h b/libraries/AP_AHRS/AP_AHRS.h
index 0ffc3b5ee8..bbdcbf7f7e 100644
--- a/libraries/AP_AHRS/AP_AHRS.h
+++ b/libraries/AP_AHRS/AP_AHRS.h
@@ -164,7 +164,8 @@ public:
     virtual void update(bool skip_ins_update=false) = 0;
 
     // returns false if we fail arming checks, in which case the buffer will be populated with a failure message
-    virtual bool pre_arm_check(char *failure_msg, uint8_t failure_msg_len) const = 0;
+    // requires_position should be true if horizontal position configuration should be checked
+    virtual bool pre_arm_check(bool requires_position, char *failure_msg, uint8_t failure_msg_len) const = 0;
 
     // check all cores providing consistent attitudes for prearm checks
     virtual bool attitudes_consistent(char *failure_msg, const uint8_t failure_msg_len) const { return true; }
diff --git a/libraries/AP_AHRS/AP_AHRS_DCM.cpp b/libraries/AP_AHRS/AP_AHRS_DCM.cpp
index ba608027af..9a4db95188 100644
--- a/libraries/AP_AHRS/AP_AHRS_DCM.cpp
+++ b/libraries/AP_AHRS/AP_AHRS_DCM.cpp
@@ -1152,7 +1152,8 @@ bool AP_AHRS_DCM::get_velocity_NED(Vector3f &vec) const
 }
 
 // returns false if we fail arming checks, in which case the buffer will be populated with a failure message
-bool AP_AHRS_DCM::pre_arm_check(char *failure_msg, uint8_t failure_msg_len) const
+// requires_position should be true if horizontal position configuration should be checked (not used)
+bool AP_AHRS_DCM::pre_arm_check(bool requires_position, char *failure_msg, uint8_t failure_msg_len) const
 {
     if (!healthy()) {
         hal.util->snprintf(failure_msg, failure_msg_len, "Not healthy");
diff --git a/libraries/AP_AHRS/AP_AHRS_DCM.h b/libraries/AP_AHRS/AP_AHRS_DCM.h
index 43dfcc990c..c4a2f580e3 100644
--- a/libraries/AP_AHRS/AP_AHRS_DCM.h
+++ b/libraries/AP_AHRS/AP_AHRS_DCM.h
@@ -121,7 +121,8 @@ public:
     bool get_velocity_NED(Vector3f &vec) const override;
 
     // 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 override;
+    // requires_position should be true if horizontal position configuration should be checked (not used)
+    bool pre_arm_check(bool requires_position, char *failure_msg, uint8_t failure_msg_len) const override;
 
 private:
     float _ki;
diff --git a/libraries/AP_AHRS/AP_AHRS_NavEKF.cpp b/libraries/AP_AHRS/AP_AHRS_NavEKF.cpp
index 9bbf1d2bf3..32746ab58c 100644
--- a/libraries/AP_AHRS/AP_AHRS_NavEKF.cpp
+++ b/libraries/AP_AHRS/AP_AHRS_NavEKF.cpp
@@ -1668,7 +1668,8 @@ bool AP_AHRS_NavEKF::healthy(void) const
 }
 
 // returns false if we fail arming checks, in which case the buffer will be populated with a failure message
-bool AP_AHRS_NavEKF::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 AP_AHRS_NavEKF::pre_arm_check(bool requires_position, char *failure_msg, uint8_t failure_msg_len) const
 {
     bool ret = true;
     if (!healthy()) {
@@ -1705,7 +1706,7 @@ bool AP_AHRS_NavEKF::pre_arm_check(char *failure_msg, uint8_t failure_msg_len) c
             hal.util->snprintf(failure_msg, failure_msg_len, "EKF3 not started");
             return false;
         }
-        return EKF3.pre_arm_check(failure_msg, failure_msg_len) && ret;
+        return EKF3.pre_arm_check(requires_position, failure_msg, failure_msg_len) && ret;
 #endif
     }
 
diff --git a/libraries/AP_AHRS/AP_AHRS_NavEKF.h b/libraries/AP_AHRS/AP_AHRS_NavEKF.h
index bbbb78d20a..5d0307ceca 100644
--- a/libraries/AP_AHRS/AP_AHRS_NavEKF.h
+++ b/libraries/AP_AHRS/AP_AHRS_NavEKF.h
@@ -203,7 +203,8 @@ public:
     bool healthy() const override;
 
     // 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 override;
+    // 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 override;
 
     // true if the AHRS has completed initialisation
     bool initialised() const override;