From 81e453dee3e456ebcb34da7bfd78d6a9b5a16ea3 Mon Sep 17 00:00:00 2001
From: Michael du Breuil <wicked.shell.scripts@gmail.com>
Date: Thu, 10 May 2018 21:03:06 -0700
Subject: [PATCH] AP_Arming: Restrict GPS/AHRS difference to a 2D solution

---
 libraries/AP_Arming/AP_Arming.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libraries/AP_Arming/AP_Arming.cpp b/libraries/AP_Arming/AP_Arming.cpp
index 27cb5c7e37..bb92bb34a4 100644
--- a/libraries/AP_Arming/AP_Arming.cpp
+++ b/libraries/AP_Arming/AP_Arming.cpp
@@ -384,7 +384,7 @@ bool AP_Arming::gps_checks(bool report)
         Location gps_loc = gps.location();
         Location ahrs_loc;
         if (ahrs.get_position(ahrs_loc)) {
-            float distance = location_3d_diff_NED(gps_loc, ahrs_loc).length();
+            const float distance = location_diff(gps_loc, ahrs_loc).length();
             if (distance > AP_ARMING_AHRS_GPS_ERROR_MAX) {
                 if (report) {
                     gcs().send_text(MAV_SEVERITY_CRITICAL, "PreArm: GPS and AHRS differ by %4.1fm", (double)distance);