#!/bin/sh
#
# Path tracking by GPS waypoints on Neo/Freerunner GTA02
# Use CTRL+C to stop
#
# $ gpx [sample-interval [fix-tryout-interval]]
#
# The intervals are measured in seconds. If no values are
# given, the defaultvalues will be taken.
# - sample-interval = 30sec
# - fix-tryout-interval = 90sec 
#
# 20090418 saves output as GPX file, validation can be made 
#          xmllint --noout --schema http://www.topografix.com/GPX/1/1/gpx.xsd sample.gpx 
#          intervals configurable by parameters
# 20090511 saves output as GPX Waypoint and GPX Route 
# 20090705 bugfix invalid route xml format
#
###############################################################

# use only initialized variables
set -o nounset

GPSPOWER=/sys/bus/platform/devices/neo1973-pm-gps.0/pwron
GPSDEVICE=/dev/ttySAC1
GPSDATATYPE=\$GPGLL
GPSDATA=""
GPSSTATE=""
GPSWP=/media/card/gps/wp-`date +%Y%m%d-%H%M`.gpx
GPSROUTE=/media/card/gps/route-`date +%Y%m%d-%H%M`.gpx
GPSFIXRETRY=90
GPSINTERVAL=30
GPSLOG=/media/card/gps/gps.log
GPSSIVTYPE=\$GPGSV

APGSONLINE=/media/card/gps/gps-online

if [ $# -ge 1 ]; then
  GPSINTERVAL=$1
  echo "GPS sample interval ${GPSINTERVAL} sec"

  if [ $# -eq 2 ]; then
    GPSFIXRETRY=$2
  fi
fi

##############################################################
CleanUp() {
  # shutdown GPS chip for powersaving                                 
  echo "0" > $GPSPOWER                                    
  # write gpx footer
  echo "</gpx>" >> $GPSWP
  echo " </rte>" >> $GPSROUTE
  echo "</gpx>" >> $GPSROUTE
  # manually sync the disk   
  sync

  trap - INT TERM EXIT 
  echo "GPS cleanup ..."
  exit
}

trap CleanUp INT TERM EXIT

##############################################################

# begin trackrecording
rm -f $GPSWP > /dev/null 2>&1
rm -f $GPSLOG > /dev/null 2>&1

# write gpx header
echo "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\" ?>" >> $GPSWP
echo "<gpx xmlns=\"http://www.topografix.com/GPX/1/1\" creator=\"byHand\" version=\"1.1\"" >> $GPSWP 
echo "    xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"" >> $GPSWP 
echo "    xsi:schemaLocation=\"http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd\"" >> $GPSWP
echo ">" >> $GPSWP

echo "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\" ?>" >> $GPSROUTE
echo "<gpx xmlns=\"http://www.topografix.com/GPX/1/1\" creator=\"byHand\" version=\"1.1\"" >> $GPSROUTE
echo "    xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"" >> $GPSROUTE                        
echo "    xsi:schemaLocation=\"http://www.topografix.com/GPX/1/1 http://www.topografix.com/GPX/1/1/gpx.xsd\"" >> $GPSROUTE
echo ">" >> $GPSROUTE  
echo "<rte>" >> $GPSROUTE

#############################################################

# reset GPS chip - if necessary
echo "Initializing gps ..."
if [ $(cat $GPSPOWER) -eq 1 ]; then
  echo "Stop already running gps operations..." 
  echo "0" > $GPSPOWER
  sleep 1
fi
echo "1" > $GPSPOWER
sleep 1

echo "Trying assisted-gps..."
ONLINE=$(ping -c 1 194.116.196.131)  
if [ $? -eq 0 ]; then
  echo "Using online assisted-gps ..."
  . $APGSONLINE > $GPSDEVICE
  sleep 1
else
  echo "No assisted-gps found"
fi

##############################################################
while true; do

  FIX=""

  ############################################################
  # wait till fix found before going on
  while true; do

    SAMPLE=""
    while [ -z $SAMPLE ]; do
      SAMPLE=$(head -n 3 $GPSDEVICE | grep $GPSDATATYPE) 
    done
    echo $SAMPLE >> $GPSLOG 
    # some converter needs the complete record
    echo "<!-- $SAMPLE -->" >> $GPSWP

    FIX=$( echo $SAMPLE | grep ",A,")                             
    if [ -z "$FIX" ]; then                                        
       echo "No gps fix yet - wait $GPSFIXRETRY seconds and retry ..."
    else                                                          
       break                # fix found - continue                
    fi  

    # write some feedback
    SIV=""
    while [ -z $SIV ]; do                                  
      SIV=$(head -n 3 $GPSDEVICE | grep $GPSSIVTYPE)      
    done                                                      
    echo $SIV >> $GPSLOG

    SIVNOTNULL=$( echo $SIV | grep ",1,1,00")
    if [ -n "$SIVNOTNULL" ]; then                                           
       echo "No satellites found yet..." 
    else                                                             
       SIV=$(echo $SIV | sed 's/,/ /g' | awk '{ print $4 }' ) 
       echo "$SIV satellites in view"
    fi  

    sleep $GPSFIXRETRY   # no fix - wait and retry
  done
  ############################################################

  # analyze & save valid gps sample
  GPSDATA=$(echo $SAMPLE | sed 's/,/ /g')
  #echo "GPSDATA $GPSDATA"

  PART1=$( echo $GPSDATA | awk '{ print $1 }')
  PART2=$( echo $GPSDATA | awk '{ print $2 }') 
  PART3=$( echo $GPSDATA | awk '{ print $3 }') 
  PART4=$( echo $GPSDATA | awk '{ print $4 }') 
  PART5=$( echo $GPSDATA | awk '{ print $5 }') 
  PART6=$( echo $GPSDATA | awk '{ print $6 }') 
  #PART7=$( echo $GPSDATA | awk '{ print $7 }') 
  #PART8=$( echo $GPSDATA | awk '{ print $8 }') 

  HOURS=$(echo $PART6 | cut -c1-2)
  MINUTES=$(echo $PART6 | cut -c3-4)
  SECONDS=$(echo $PART6 | cut -c5-6)
  PART6=$HOURS:$MINUTES:$SECONDS

  #echo "GPS ${PART2}${PART3} / ${PART4}${PART5} at ${PART6} GMT" >> $GPSWP 
  echo "GPS ${PART2}${PART3} / ${PART4}${PART5} at ${PART6} GMT"

  GPSLATGRAD=$(echo $PART2 | cut -c1-2)
  GPSLATMIN=$(echo $PART2 | cut -c3-10)
  GPSLONGGRAD=$(echo $PART4 | cut -c1-3)
  GPSLONGMIN=$(echo $PART4 | cut -c4-11)

  GPXLAT=$(echo "$GPSLATGRAD $GPSLATMIN" | awk '{ dezimal = $1 + $2 / 60 } END { printf("%2.8f"), dezimal }' ) 
  GPXLONG=$(echo "$GPSLONGGRAD $GPSLONGMIN" | awk '{ dezimal = $1 + $2 / 60 } END { printf("%3.8f"), dezimal }' )

  echo "<wpt lat=\"${GPXLAT}\" lon=\"${GPXLONG}\">" >> $GPSWP
  echo " <time>$(date +%Y-%m-%d)T${HOURS}:${MINUTES}:${SECONDS}Z</time>" >> $GPSWP
  echo "</wpt>" >> $GPSWP 

  echo "   <rtept lat=\"${GPXLAT}\" lon=\"${GPXLONG}\">" >> $GPSROUTE                                                             
  echo "    <time>$(date +%Y-%m-%d)T${HOURS}:${MINUTES}:${SECONDS}Z</time>" >> $GPSROUTE                                      
  echo "   </rtept>" >> $GPSROUTE   

  # wait till time for next sample
  sleep $GPSINTERVAL 
done

##############################################################
# EOF
##############################################################