From 9f02834f6d6a658dcccbb9788165235a5ef82791 Mon Sep 17 00:00:00 2001
From: Michael du Breuil <michael@swiftradioplanes.com>
Date: Mon, 7 Sep 2015 15:37:13 -0700
Subject: [PATCH] AP_GPS: Broadcast vDOP data over mavlink

---
 libraries/AP_GPS/AP_GPS.cpp | 4 ++--
 libraries/AP_GPS/AP_GPS.h   | 8 ++++++++
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/libraries/AP_GPS/AP_GPS.cpp b/libraries/AP_GPS/AP_GPS.cpp
index a8a1c40c86..b854ee9d3a 100644
--- a/libraries/AP_GPS/AP_GPS.cpp
+++ b/libraries/AP_GPS/AP_GPS.cpp
@@ -551,7 +551,7 @@ AP_GPS::send_mavlink_gps_raw(mavlink_channel_t chan)
         loc.lng,        // in 1E7 degrees
         loc.alt * 10UL, // in mm
         get_hdop(0),
-        65535,
+        get_vdop(0),
         ground_speed(0)*100,  // cm/s
         ground_course_cd(0), // 1/100 degrees,
         num_sats(0));
@@ -580,7 +580,7 @@ AP_GPS::send_mavlink_gps2_raw(mavlink_channel_t chan)
         loc.lng,
         loc.alt * 10UL,
         get_hdop(1),
-        65535,
+        get_vdop(1),
         ground_speed(1)*100,  // cm/s
         ground_course_cd(1), // 1/100 degrees,
         num_sats(1),
diff --git a/libraries/AP_GPS/AP_GPS.h b/libraries/AP_GPS/AP_GPS.h
index 4effa17146..318bf2a324 100644
--- a/libraries/AP_GPS/AP_GPS.h
+++ b/libraries/AP_GPS/AP_GPS.h
@@ -282,6 +282,14 @@ public:
         return get_hdop(primary_instance);
     }
 
+    // vertical dilution of precision
+    uint16_t get_vdop(uint8_t instance) const {
+        return _GPS_STATE(instance).vdop;
+    }
+    uint16_t get_vdop() const {
+        return get_vdop(primary_instance);
+    }
+
     // the time we got our last fix in system milliseconds. This is
     // used when calculating how far we might have moved since that fix
     uint32_t last_fix_time_ms(uint8_t instance) const {