From 6776f9c02d5ec846a92dea79c1c58f87df276b69 Mon Sep 17 00:00:00 2001
From: Sam Cook <github@sam.net.nz>
Date: Fri, 8 May 2015 18:12:29 +0100
Subject: [PATCH] Send a (non-zero) fake location when GPS isn't present to
 enable display of compass heading on OpenTX

---
 src/main/telemetry/frsky.c | 31 ++++++++++++++++---------------
 1 file changed, 16 insertions(+), 15 deletions(-)

diff --git a/src/main/telemetry/frsky.c b/src/main/telemetry/frsky.c
index 073f8cf128..b72e3fff71 100644
--- a/src/main/telemetry/frsky.c
+++ b/src/main/telemetry/frsky.c
@@ -302,12 +302,18 @@ static void sendLatLong(int32_t coord[2])
     serialize16(coord[LON] < 0 ? 'W' : 'E');
 }
 
-
-static void sendFakeLatLong(void)
+static void sendFakeLatLong(bool useGpsNoFixValues)
 {
+    // Heading is only displayed on OpenTX if non-zero lat/long is also sent
     int32_t coord[2] = {0,0};
-    coord[LAT] = (telemetryConfig->gpsNoFixLatitude * GPS_DEGREES_DIVIDER);
-    coord[LON] = (telemetryConfig->gpsNoFixLongitude * GPS_DEGREES_DIVIDER);
+    
+    if (useGpsNoFixValues) {
+        coord[LAT] = (telemetryConfig->gpsNoFixLatitude * GPS_DEGREES_DIVIDER);
+        coord[LON] = (telemetryConfig->gpsNoFixLongitude * GPS_DEGREES_DIVIDER);
+    } else {
+        coord[LAT] = (1 * GPS_DEGREES_DIVIDER);
+        coord[LON] = (1 * GPS_DEGREES_DIVIDER);
+    }
 
     sendLatLong(coord);
 }
@@ -315,17 +321,15 @@ static void sendFakeLatLong(void)
 #ifdef GPS
 static void sendGPSLatLong(void)
 {
-    // Don't set dummy GPS data, if we already had a GPS fix
-    // it can be usefull to keep last valid coordinates
     static uint8_t gpsFixOccured = 0;
 
-    //Dummy data if no 3D fix, this way we can display heading in Taranis
     if (STATE(GPS_FIX) || gpsFixOccured == 1) {
+        // If we have ever had a fix, send the last known lat/long
         gpsFixOccured = 1;
         sendLatLong(GPS_coord);
     } else {
-        // Send dummy GPS Data in order to display compass value
-        sendFakeLatLong();
+        // otherwise send fake lat/long in order to display compass value
+        sendFakeLatLong(true);
     }
 }
 #endif
@@ -521,14 +525,11 @@ void handleFrSkyTelemetry(rxConfig_t *rxConfig, uint16_t deadband3d_throttle)
             sendSatalliteSignalQualityAsTemperature2();
             sendGPSLatLong();
         }
-        else if (telemetryConfig->gpsNoFixLatitude != 0 && telemetryConfig->gpsNoFixLongitude != 0) {
-            sendFakeLatLong();
+        else {
+            sendFakeLatLong(false);
         }
 #else
-        //  Send GPS information to display compass information
-        if (telemetryConfig->gpsNoFixLatitude != 0 && telemetryConfig->gpsNoFixLongitude != 0) {
-            sendFakeLatLong();
-        }
+        sendFakeLatLong(false);
 #endif
 
         sendTelemetryTail();