From f4692a378403c743678c4e7911e949c39d57643a Mon Sep 17 00:00:00 2001
From: Eric Tran <eric.tran@graceful.hou.flightaware.com>
Date: Tue, 28 Aug 2018 17:08:14 +0000
Subject: [PATCH] Ignore altitude reporting when part of airborne position
 message with air/ground=ground

---
 mode_s.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mode_s.c b/mode_s.c
index 5c35962..606ddf7 100644
--- a/mode_s.c
+++ b/mode_s.c
@@ -974,7 +974,7 @@ static void decodeESAirbornePosition(struct modesMessage *mm, int check_imf)
         }
     }
 
-    if (AC12Field) {// Only attempt to decode if a valid (non zero) altitude is present
+    if (AC12Field && mm->airground != AG_GROUND) {// Only attempt to decode if a valid (non zero) altitude is present and not on ground
         altitude_unit_t unit;
         int alt = decodeAC12Field(AC12Field, &unit);
         if (alt != INVALID_ALTITUDE) {