From 2e484d73af8cbde5330afd1e889f04391bb03e8f Mon Sep 17 00:00:00 2001
From: kn1gh7h4wk <49842470+kn1gh7h4wk@users.noreply.github.com>
Date: Mon, 22 Jun 2020 19:22:58 -0700
Subject: [PATCH] Update gpsUpdate.sh

---
 bin/gpsUpdate.sh | 59 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)
 create mode 100644 bin/gpsUpdate.sh

diff --git a/bin/gpsUpdate.sh b/bin/gpsUpdate.sh
new file mode 100644
index 0000000..816a676
--- /dev/null
+++ b/bin/gpsUpdate.sh
@@ -0,0 +1,59 @@
+#!/bin/bash
+
+## ADD THE FOLLOWING TO CRONJOB: @reboot gpsUpdate.sh >> /home/pi/.gpsUpdate.log 2>&1
+
+gpsLat="0.003"  #default value is 0.002, (1,108 ft LAT)
+gpsLon="0.004"  #default value is 0.002, (1,215 ft LON)
+
+########## DO NOT EDIT BELOW THIS LINE ##########
+########## DO NOT EDIT BELOW THIS LINE ##########
+########## DO NOT EDIT BELOW THIS LINE ##########
+
+source /boot/adsb-config.txt
+
+latA="$LATITUDE"
+lonA="$LONGITUDE"
+
+echo "Starting GPS position updater with a GPS coordinate precision of ${gpsLat}° latitude and ${gpsLon}° longitude." | ts
+echo "Last known coodinates: $latA, $lonA" | ts
+
+gpspipe -d -w -o /tmp/gpsDump
+
+while [ -f /tmp/gpsDump ] ; do
+  if grep -q 'lat\|lon\|alt' /tmp/gpsDump ; then
+    LAT=$(cat /tmp/gpsDump | awk 'BEGIN{RS=","; FS=":"} /lat/ {save=$2} END {print save}')
+    LON=$(cat /tmp/gpsDump | awk 'BEGIN{RS=","; FS=":"} /lon/ {save=$2} END {print save}')
+    ALT=$(cat /tmp/gpsDump | awk 'BEGIN{RS=","; FS=":"} /alt/ {save=$2} END {print save}')
+    ALT=$(echo "scale=0; $ALT * 3.281/1" | bc)
+    latB=$(echo "scale=3; $LAT /1" | bc)
+    lonB=$(echo "scale=3; $LON /1" | bc)
+    latP=$(echo "define abs(i) {if (i < 0) return (-i); return (i)}; abs($latA - $latB) <= $gpsLat" | bc)
+    lonP=$(echo "define abs(i) {if (i < 0) return (-i); return (i)}; abs($lonA - $lonB) <= $gpsLon" | bc)
+    echo "$(tail -n 499 /home/pi/.gpsUpdate.log)" > /home/pi/.gpsUpdate.log
+
+    if [ $latP -eq 1 ] && [ $lonP -eq 1 ] ; then
+      echo "GPS Poisition $LAT, $LON is update to date!" | ts
+      killall gpspipe
+      rm /tmp/gpsDump
+      # sleep 600 # systemd will restart the script after 600 secs (10 min)
+      # gpspipe -d -w -o /tmp/gpsDump
+      # echo "Checking current GPS position..." | ts
+
+    elif [ $ALT -gt -1500 ] ; then
+      echo "Updating LAT: ${LAT}°, LON: ${LON}°, ELEV: ${ALT}ft" | ts
+      cat > /boot/adsb-config.txt <<- EOL
+	LATITUDE=$LAT
+	LONGITUDE=$LON
+	ALTITUDE=${ALT}ft
+	USER="$USER"
+	DUMP1090=$DUMP1090
+	GAIN=$GAIN
+	DUMP978=$DUMP978
+	EOL
+      systemctl restart readsb
+      systemctl restart adsbexchange-mlat.service
+      latA=$latB
+      lonA=$lonB
+    fi
+  fi
+done