import serial
import Adafruit_BBIO.UART as UART
from time import sleep
UART.setup("UART1")
ser=serial.Serial('/dev/ttyO1',9600)
class GPS:
        def __init__(self):
                #This sets up variables for useful commands.
                #This set is used to set the rate the GPS reports
                UPDATE_10_sec=  "$PMTK220,10000*2F\r\n" #Update Every 10 Seconds
                UPDATE_5_sec=  "$PMTK220,5000*1B\r\n"   #Update Every 5 Seconds  
                UPDATE_1_sec=  "$PMTK220,1000*1F\r\n"   #Update Every One Second
                UPDATE_200_msec=  "$PMTK220,200*2C\r\n" #Update Every 200 Milliseconds
                #This set is used to set the rate the GPS takes measurements
                MEAS_10_sec = "$PMTK300,10000,0,0,0,0*2C\r\n" #Measure every 10 seconds
                MEAS_5_sec = "$PMTK300,5000,0,0,0,0*18\r\n"   #Measure every 5 seconds
                MEAS_1_sec = "$PMTK300,1000,0,0,0,0*1C\r\n"   #Measure once a second
                MEAS_200_msec= "$PMTK300,200,0,0,0,0*2F\r\n"  #Meaure 5 times a second
                #Set the Baud Rate of GPS
                BAUD_57600 = "$PMTK251,57600*2C\r\n"          #Set Baud Rate at 57600
                BAUD_9600 ="$PMTK251,9600*17\r\n"             #Set 9600 Baud Rate
                #Commands for which NMEA Sentences are sent
                ser.write(BAUD_57600)
                sleep(1)
                ser.baudrate=57600
                GPRMC_ONLY= "$PMTK314,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*29\r\n" #Send only the GPRMC Sentence
                GPRMC_GPGGA="$PMTK314,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*28\r\n"#Send GPRMC AND GPGGA Sentences
                SEND_ALL ="$PMTK314,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0*28\r\n" #Send All Sentences
                SEND_NOTHING="$PMTK314,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*28\r\n" #Send Nothing
                ser.write(UPDATE_1_sec)
                sleep(1)
                ser.write(MEAS_1_sec)
                sleep(1)
                ser.write(GPRMC_GPGGA)
                sleep(1)
                ser.flushInput()
                ser.flushInput()
                print "GPS Initialized"
        def read(self):
                ser.flushInput()
                ser.flushInput()
                while ser.inWaiting()==0:
                        pass
                self.NMEA1=ser.readline()
                while ser.inWaiting()==0:
                        pass
                self.NMEA2=ser.readline()
                NMEA1_array=self.NMEA1.split(',')
                NMEA2_array=self.NMEA2.split(',')
                if NMEA1_array[0]=='$GPRMC':
                        self.timeUTC=NMEA1_array[1][:-8]+':'+NMEA1_array[1][-8:-6]+':'+NMEA1_array[1][-6:-4]
                        self.latDeg=NMEA1_array[3][:-7]
                        self.latMin=NMEA1_array[3][-7:]
                        self.latHem=NMEA1_array[4]
                        self.lonDeg=NMEA1_array[5][:-7]
                        self.lonMin=NMEA1_array[5][-7:]
                        self.lonHem=NMEA1_array[6]
                        self.knots=NMEA1_array[7]
                if NMEA1_array[0]=='$GPGGA':
                        self.fix=NMEA1_array[6]
                        self.altitude=NMEA1_array[9]
                        self.sats=NMEA1_array[7]
                if NMEA2_array[0]=='$GPRMC':
                        self.timeUTC=NMEA2_array[1][:-8]+':'+NMEA1_array[1][-8:-6]+':'+NMEA1_array[1][-6:-4]
                        self.latDeg=NMEA2_array[3][:-7]
                        self.latMin=NMEA2_array[3][-7:]
                        self.latHem=NMEA2_array[4]
                        self.lonDeg=NMEA2_array[5][:-7]
                        self.lonMin=NMEA2_array[5][-7:]
                        self.lonHem=NMEA2_array[6]
                        self.knots=NMEA2_array[7]

                if NMEA2_array[0]=='$GPGGA':
                        self.fix=NMEA2_array[6]
                        self.altitude=NMEA2_array[9]
                        self.sats=NMEA2_array[7]
myGPS=GPS()
GPSdata=open('/root/GPS_data/GPS.txt', 'w')
GPSdata.close()
while(1):
        myGPS.read()
        if myGPS.fix!=0:
                try:
			latDec=float(myGPS.latDeg)+float(myGPS.latMin)/60.
			lonDec=float(myGPS.lonDeg)+float(myGPS.lonMin)/60.
			if myGPS.lonHem=='W':
				lonDec=(-1)*lonDec
			if myGPS.latHem=='S':
				latDec=(-1)*latDec
			alt=myGPS.altitude
			GPSdata=open('/root/GPS_data/GPS.txt', 'a')
			myString=str(lonDec)+','+str(latDec)+','+alt+' '
			GPSdata.write(myString)
			GPSdata.close()
		except:
			pass