From 9ee35e38df8884c261381b53d0a35d2ea55ceebc Mon Sep 17 00:00:00 2001
From: Paul Riseborough <p_riseborough@live.com.au>
Date: Tue, 4 Jul 2017 20:33:14 +1000
Subject: [PATCH] EKF: Don't fallback when optical flow is lost if external
 vision data is being used

---
 EKF/control.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/EKF/control.cpp b/EKF/control.cpp
index 55b3d12cf9..97d3828085 100644
--- a/EKF/control.cpp
+++ b/EKF/control.cpp
@@ -336,7 +336,7 @@ void Ekf::controlOpticalFlowFusion()
 		}
 
 		// handle the case when we are relying on optical flow fusion and lose it
-		if (_control_status.flags.opt_flow && !_control_status.flags.gps) {
+		if (_control_status.flags.opt_flow && !_control_status.flags.gps && !_control_status.flags.ev_pos) {
 			// We are relying on flow aiding to constrain attitude drift so after 5s without aiding we need to do something
 			if ((_time_last_imu - _time_last_of_fuse > 5e6)) {
 				// Switch to the non-aiding mode, zero the velocity states