From f3e34eddc9727d4f676233452d3a00c7a96d0c11 Mon Sep 17 00:00:00 2001
From: Paul Riseborough <p_riseborough@live.com.au>
Date: Thu, 9 Nov 2017 17:39:56 +1100
Subject: [PATCH] EKF: do not attempt to align FW yaw using GPS method if on
 ground

---
 EKF/control.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/EKF/control.cpp b/EKF/control.cpp
index dee0f44360..3cfa2311d8 100644
--- a/EKF/control.cpp
+++ b/EKF/control.cpp
@@ -483,8 +483,8 @@ void Ekf::controlGpsFusion()
 			do_reset = do_reset || (_time_last_imu - _time_last_pos_fuse > 2 * _params.no_gps_timeout_max);
 
 			if (do_reset) {
-				// Reset states to the last GPS measurement
-				if (_control_status.flags.fixed_wing) {
+				// use GPS velocity data to cehck and correct yaw angle if a FW vehicle
+				if (_control_status.flags.fixed_wing && _control_status.flags.in_air) {
 					// if flying a fixed wing aircraft, do a complete reset that includes yaw
 					realignYawGPS();
 				}