micro-python/gps/gps.py

import machine
import time
import struct

class NMEA(object):
    def __init__(self, id):
        self.__id = str(id)

class Value(object):
    def __init__(self, v, u, t=(0,0,0.0)):
        self.__val = float(v)
        self.__unit = u
        self.__time = t

    def value(self):
        return self.__val

    def unit(self):
        return self.__unit

    def time(self):
        return self.__time

    def rad(self):
        return self.__val * math.pi / 180

    def __repr__(self):
        return "%f %s" % (self.value(), self.unit())

    def __float__(self):
        return float(self.__val)

class Distance(Value):
    def __init__(self, v, u, t):
        super().__init__(v, u, t)

class Position(Value):
    def __init__(self, v, u, t):
        super().__init__(v if u in ("N", "E") else -v, u, t)

    def __sub__(self, other):
        return Position(self.value() - other.value())

class Speed(Value):
    def __init__(self, v, u, t):
        super().__init__(v, u, t)

    def to_kmh(self):
        if self.unit() in ("knot", "N"):
            return Speed(self.value() * 1.85200, "kmh", self.time())
        return self

    def to_knot(self):
        if self.unit() in ("kmh", "K"):
            return Speed(self.value() / 1.85200, "knot", self.time())
        return self

class Course(Value):
    def __init__(self, v, t):
        super().__init__(v, "D", t)

class Location(object):
    def __init__(self):
        self.__valid = False
        self.__lat = None
        self.__long = None
        self.__alt = None
        self.__height = None
        self.__speed = None
        self.__course = None
        self.__satellites = -1

    def __repr__(self):
        return "Satelittes: %s, %s\n\tLat/long: %s/%s\n\tAlt/h: %s/%s\n\tSpeed/course: %s/%s" % (
            self.__satellites, repr(self.__valid),
            self.__lat, self.__lat,
            self.__alt, self.__height,
            self.__speed, self.__course,
        )

    def set(self, msgid, segment):
        data = segment.split(",")
        if msgid == b'$GPGGA':
            if len(data) >= 6 and data[5] in ("1", "2", "6"):
                t = self.__time_from_seg(data[0])
                self.__set_lat(data[1], data[2], t)
                self.__set_long(data[3], data[4], t)

                if self.__satellites < 0 and self.__seg_set(data, 6):
                    self.__satellites = int(data[6])

                if self.__seg_set(data, 7):
                    self.__alt = Distance(data[7], "M", t)

                if self.__seg_set(data, 8):
                    self.__height = Distance(data[8], "M", t)
        elif msgid == b'$GPGLL':
            if len(data) >= 6 and data[5] == "A":
                t = self.__time_from_seg(data[4])
                self.__set_lat(data[0], data[1], t)
                self.__set_long(data[2], data[3], t)
        elif msgid == b'$GPRMC':
            if len(data) >= 6 and data[1] == "A":
                t = self.__time_from_seg(data[0])
                self.__set_lat(data[2], data[3], t)
                self.__set_long(data[4], data[5], t)
                self.__set_speed(data[6], "N", t)
                self.__set_course(data[7], t)
        elif msgid == b'$GPVTG':
            if len(data) >= 7 and data[2] == "T":
                self.__set_speed(data[4], data[6], (0, 0, 0.0))
                self.__set_course(data[5], data[0], (0, 0, 0.0))
        elif msgid == b'$GPGSV':
            if self.__seg_set(data, 2) and data[0] == data[1]:
                self.__satellites = int(data[2])
        elif msgid == b'$GPMSS':
            pass

        self.__valid = False if self.__lat is None or self.__long is None else True

        return self.valid()

    def valid(self):
        return self.__valid

    def __seg_set(self, d, i):
        return len(d) >= (i + 1) and len(d[i]) != 0

    def __set_speed(self, v, u, t):
        if len(v) == 0:
            return None

        if self.__speed is None or self.__speed.time() < t:
            self.__speed = Speed(v, u, t)

    def __set_course(self, v, t):

        if len(v) == 0:
            return None
        print("Course", v, t)

        if self.__course is None or self.__course.time() < t:
            self.__course = Course(v, t)

    def __set_lat(self, v, d, t):
        if len(v) == 0:
            return None

        if self.__lat is None or self.__lat.time() < t:
            self.__lat = Position(float(v[0:2]) + (float(v[2:]) / 60), d, t)

    def __set_long(self, v, d, t):
        if len(v) == 0:
            return None

        if self.__long is None or self.__long.time() < t:
            self.__long = Position(float(v[0:3]) + (float(v[3:]) / 60), d, t)

    def __time_from_seg(self, ts):
        return (int(ts[0:2]), int(ts[2:4]), float(ts[4:]))

class Data(object):
    def __init__(self, pins=("P3", "P4"), baud=9600):
        self.__com = machine.UART(1, pins=pins, baudrate=baud)
        self.__location = None
        self.__last_update = time.time()

    def new_location(self, ttw=5):
        
        if time.time() - (self.__last_update + ttw) < 0:
            return False

        self.__data = Location()
        data = []

        while self.__com.any():
            tmp_data = self.__com.readline()

            if tmp_data[0:1] == b'$':
                self.__update(data)
                data = [tmp_data]
            elif len(data) != 0:
                data.append(tmp_data)
        else:
            self.__update(data)
        
        return self.__data.valid()

    def get_location(self):
        return self.__data

    def __update(self, data):

        if len(data) == 0:
            return False

        data = b''.join(data)

        if data[len(data)-1:len(data)] not in (b'\n', b'\r'):
            return False

        if data[len(data)-1:len(data)] != b'\n':
            data += '\n'

        if self.__data.set(data[0:6], ("%s" % (data[7:len(data)-2],))[2:-1]):
            self.__last_update = time.time()