457 lines
12 KiB
C++
457 lines
12 KiB
C++
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/*
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TinyGPS - a small GPS library for Arduino providing basic NMEA parsing
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Based on work by and "distance_to" and "course_to" courtesy of Maarten Lamers.
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Suggestion to add satellites(), course_to(), and cardinal(), by Matt Monson.
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Copyright (C) 2008-2012 Mikal Hart
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All rights reserved.
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "TinyGPS.h"
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#define _GPRMC_TERM "GPRMC"
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#define _GPGGA_TERM "GPGGA"
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TinyGPS::TinyGPS()
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: _time(GPS_INVALID_TIME)
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, _date(GPS_INVALID_DATE)
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, _latitude(GPS_INVALID_ANGLE)
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, _longitude(GPS_INVALID_ANGLE)
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, _altitude(GPS_INVALID_ALTITUDE)
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, _speed(GPS_INVALID_SPEED)
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, _course(GPS_INVALID_ANGLE)
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, _hdop(GPS_INVALID_HDOP)
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, _numsats(GPS_INVALID_SATELLITES)
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, _last_time_fix(GPS_INVALID_FIX_TIME)
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, _last_position_fix(GPS_INVALID_FIX_TIME)
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, _parity(0)
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, _is_checksum_term(false)
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, _sentence_type(_GPS_SENTENCE_OTHER)
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, _term_number(0)
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, _term_offset(0)
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, _gps_data_good(false)
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#ifndef _GPS_NO_STATS
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, _good_sentences(0)
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, _failed_checksum(0)
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#endif
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{
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_term[0] = '\0';
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}
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//
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// public methods
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//
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bool TinyGPS::encode(char c)
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{
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bool valid_sentence = false;
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switch(c)
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{
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case ',': // term terminators
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_parity ^= ',';
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case '\r':
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case '\n':
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case '*':
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if (_term_offset < sizeof(_term))
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{
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_term[_term_offset] = 0;
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valid_sentence = term_complete();
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}
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++_term_number;
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_term_offset = 0;
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_is_checksum_term = c == '*';
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return valid_sentence;
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case '$': // sentence begin
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_term_number = _term_offset = 0;
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_parity = 0;
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_sentence_type = _GPS_SENTENCE_OTHER;
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_is_checksum_term = false;
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_gps_data_good = false;
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return valid_sentence;
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}
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// ordinary characters
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if (_term_offset < sizeof(_term) - 1)
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_term[_term_offset++] = c;
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if (!_is_checksum_term)
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_parity ^= (byte)c;
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return valid_sentence;
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}
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#ifndef _GPS_NO_STATS
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void TinyGPS::stats(unsigned short *sentences, unsigned short *failed_cs)
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{
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if (sentences) *sentences = _good_sentences;
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if (failed_cs) *failed_cs = _failed_checksum;
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}
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#endif
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//
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// internal utilities
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//
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byte TinyGPS::from_hex(char a)
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{
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if (a >= 'A' && a <= 'F')
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return a - 'A' + 10;
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else if (a >= 'a' && a <= 'f')
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return a - 'a' + 10;
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else
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return a - '0';
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}
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byte TinyGPS::hex2uint8(const char *p)
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{
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byte c1 = *p;
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byte c2 = *(p + 1);
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if (c1 >= 'A' && c1 <= 'F')
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c1 -= 7;
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else if (c1 >= 'a' && c1 <= 'f')
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c1 -= 39;
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else if (c1 < '0' || c1 > '9')
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return 0;
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if (c2 == 0)
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return (c1 & 0xf);
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else if (c2 >= 'A' && c2 <= 'F')
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c2 -= 7;
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else if (c2 >= 'a' && c2 <= 'f')
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c2 -= 39;
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else if (c2 < '0' || c2 > '9')
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return 0;
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return c1 << 4 | (c2 & 0xf);
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}
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unsigned long TinyGPS::parse_decimal()
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{
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char *p = _term;
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bool isneg = *p == '-';
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if (isneg) ++p;
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unsigned long ret = 100UL * gpsatol(p);
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while (gpsisdigit(*p)) ++p;
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if (*p == '.')
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{
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if (gpsisdigit(p[1]))
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{
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ret += 10 * (p[1] - '0');
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if (gpsisdigit(p[2]))
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ret += p[2] - '0';
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}
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}
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return isneg ? -ret : ret;
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}
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unsigned long TinyGPS::parse_degrees()
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{
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char *p;
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unsigned long left = gpsatol(_term);
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unsigned long tenk_minutes = (left % 100UL) * 100000UL;
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for (p=_term; gpsisdigit(*p); ++p);
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if (*p == '.')
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{
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unsigned long mult = 10000;
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while (gpsisdigit(*++p))
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{
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tenk_minutes += mult * (*p - '0');
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mult /= 10;
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}
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}
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return (left / 100) * 1000000 + tenk_minutes / 6;
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}
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#define COMBINE(sentence_type, term_number) (((unsigned)(sentence_type) << 5) | term_number)
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// Processes a just-completed term
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// Returns true if new sentence has just passed checksum test and is validated
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bool TinyGPS::term_complete()
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{
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if (_is_checksum_term)
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{
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byte checksum = hex2uint8(_term);
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if (checksum == _parity)
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{
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#ifndef _GPS_NO_STATS
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++_good_sentences;
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#endif
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if (_gps_data_good)
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{
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_last_time_fix = _new_time_fix;
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_last_position_fix = _new_position_fix;
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switch(_sentence_type)
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{
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case _GPS_SENTENCE_GPRMC:
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_time = _new_time;
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_date = _new_date;
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_latitude = _new_latitude;
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_longitude = _new_longitude;
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_speed = _new_speed;
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_course = _new_course;
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break;
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case _GPS_SENTENCE_GPGGA:
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_altitude = _new_altitude;
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_time = _new_time;
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_latitude = _new_latitude;
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_longitude = _new_longitude;
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_numsats = _new_numsats;
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_hdop = _new_hdop;
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break;
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}
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return true;
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}
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}
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#ifndef _GPS_NO_STATS
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else
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++_failed_checksum;
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#endif
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return false;
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}
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// the first term determines the sentence type
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if (_term_number == 0)
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{
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if (!gpsstrcmp(_term, _GPRMC_TERM))
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_sentence_type = _GPS_SENTENCE_GPRMC;
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else if (!gpsstrcmp(_term, _GPGGA_TERM))
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_sentence_type = _GPS_SENTENCE_GPGGA;
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else
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_sentence_type = _GPS_SENTENCE_OTHER;
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return false;
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}
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if (_sentence_type != _GPS_SENTENCE_OTHER && _term[0])
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switch(COMBINE(_sentence_type, _term_number))
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{
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case COMBINE(_GPS_SENTENCE_GPRMC, 1): // Time in both sentences
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case COMBINE(_GPS_SENTENCE_GPGGA, 1):
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_new_time = parse_decimal();
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_new_time_fix = millis();
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break;
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case COMBINE(_GPS_SENTENCE_GPRMC, 2): // GPRMC validity
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_gps_data_good = _term[0] == 'A';
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break;
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case COMBINE(_GPS_SENTENCE_GPRMC, 3): // Latitude
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case COMBINE(_GPS_SENTENCE_GPGGA, 2):
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_new_latitude = parse_degrees();
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_new_position_fix = millis();
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break;
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case COMBINE(_GPS_SENTENCE_GPRMC, 4): // N/S
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case COMBINE(_GPS_SENTENCE_GPGGA, 3):
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if (_term[0] == 'S')
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_new_latitude = -_new_latitude;
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break;
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case COMBINE(_GPS_SENTENCE_GPRMC, 5): // Longitude
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case COMBINE(_GPS_SENTENCE_GPGGA, 4):
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_new_longitude = parse_degrees();
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break;
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case COMBINE(_GPS_SENTENCE_GPRMC, 6): // E/W
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case COMBINE(_GPS_SENTENCE_GPGGA, 5):
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if (_term[0] == 'W')
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_new_longitude = -_new_longitude;
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break;
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case COMBINE(_GPS_SENTENCE_GPRMC, 7): // Speed (GPRMC)
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_new_speed = parse_decimal();
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break;
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case COMBINE(_GPS_SENTENCE_GPRMC, 8): // Course (GPRMC)
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_new_course = parse_decimal();
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break;
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case COMBINE(_GPS_SENTENCE_GPRMC, 9): // Date (GPRMC)
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_new_date = gpsatol(_term);
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break;
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case COMBINE(_GPS_SENTENCE_GPGGA, 6): // Fix data (GPGGA)
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_gps_data_good = _term[0] > '0';
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break;
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case COMBINE(_GPS_SENTENCE_GPGGA, 7): // Satellites used (GPGGA)
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_new_numsats = (unsigned char)atoi(_term);
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break;
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case COMBINE(_GPS_SENTENCE_GPGGA, 8): // HDOP
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_new_hdop = parse_decimal();
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break;
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case COMBINE(_GPS_SENTENCE_GPGGA, 9): // Altitude (GPGGA)
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_new_altitude = parse_decimal();
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break;
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}
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return false;
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}
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long TinyGPS::gpsatol(const char *str)
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{
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long ret = 0;
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while (gpsisdigit(*str))
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ret = 10 * ret + *str++ - '0';
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return ret;
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}
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int TinyGPS::gpsstrcmp(const char *str1, const char *str2)
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{
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if (*str1 == *str2) {
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str1 += 2;
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str2 += 2;
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while (*str1 && *str1 == *str2)
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++str1, ++str2;
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}
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return *str1;
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}
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/* static */
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float TinyGPS::distance_between (float lat1, float long1, float lat2, float long2)
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{
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// returns distance in meters between two positions, both specified
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// as signed decimal-degrees latitude and longitude. Uses great-circle
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// distance computation for hypothetical sphere of radius 6372795 meters.
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// Because Earth is no exact sphere, rounding errors may be up to 0.5%.
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// Courtesy of Maarten Lamers
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float delta = radians(long1-long2);
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float sdlong = sin(delta);
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float cdlong = cos(delta);
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lat1 = radians(lat1);
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lat2 = radians(lat2);
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float slat1 = sin(lat1);
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float clat1 = cos(lat1);
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float slat2 = sin(lat2);
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float clat2 = cos(lat2);
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delta = (clat1 * slat2) - (slat1 * clat2 * cdlong);
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delta = sq(delta);
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delta += sq(clat2 * sdlong);
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delta = sqrt(delta);
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float denom = (slat1 * slat2) + (clat1 * clat2 * cdlong);
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delta = atan2(delta, denom);
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return delta * 6372795;
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}
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float TinyGPS::course_to (float lat1, float long1, float lat2, float long2)
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{
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// returns course in degrees (North=0, West=270) from position 1 to position 2,
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// both specified as signed decimal-degrees latitude and longitude.
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// Because Earth is no exact sphere, calculated course may be off by a tiny fraction.
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// Courtesy of Maarten Lamers
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float dlon = radians(long2-long1);
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lat1 = radians(lat1);
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lat2 = radians(lat2);
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float a1 = sin(dlon) * cos(lat2);
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float a2 = sin(lat1) * cos(lat2) * cos(dlon);
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a2 = cos(lat1) * sin(lat2) - a2;
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a2 = atan2(a1, a2);
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if (a2 < 0.0)
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{
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a2 += TWO_PI;
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}
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return degrees(a2);
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}
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const char *TinyGPS::cardinal (float course)
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{
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static const char* directions[] = {"N", "NNE", "NE", "ENE", "E", "ESE", "SE", "SSE", "S", "SSW", "SW", "WSW", "W", "WNW", "NW", "NNW"};
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int direction = (int)((course + 11.25f) / 22.5f);
|
||
|
|
return directions[direction % 16];
|
||
|
|
}
|
||
|
|
|
||
|
|
// lat/long in hundred thousandths of a degree and age of fix in milliseconds
|
||
|
|
void TinyGPS::get_position(long *latitude, long *longitude, unsigned long *fix_age)
|
||
|
|
{
|
||
|
|
if (latitude) *latitude = _latitude;
|
||
|
|
if (longitude) *longitude = _longitude;
|
||
|
|
if (fix_age) {
|
||
|
|
if (_last_position_fix == GPS_INVALID_FIX_TIME)
|
||
|
|
*fix_age = GPS_INVALID_AGE;
|
||
|
|
else
|
||
|
|
*fix_age = millis() - _last_position_fix;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// date as ddmmyy, time as hhmmsscc, and age in milliseconds
|
||
|
|
void TinyGPS::get_datetime(unsigned long *date, unsigned long *time, unsigned long *age)
|
||
|
|
{
|
||
|
|
if (date) *date = _date;
|
||
|
|
if (time) *time = _time;
|
||
|
|
if (age) {
|
||
|
|
if (_last_time_fix == GPS_INVALID_FIX_TIME)
|
||
|
|
*age = GPS_INVALID_AGE;
|
||
|
|
else
|
||
|
|
*age = millis() - _last_time_fix;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
void TinyGPS::f_get_position(float *latitude, float *longitude, unsigned long *fix_age)
|
||
|
|
{
|
||
|
|
long lat, lon;
|
||
|
|
get_position(&lat, &lon, fix_age);
|
||
|
|
*latitude = lat == GPS_INVALID_ANGLE ? GPS_INVALID_F_ANGLE : (lat / 100000.0);
|
||
|
|
*longitude = lat == GPS_INVALID_ANGLE ? GPS_INVALID_F_ANGLE : (lon / 100000.0);
|
||
|
|
}
|
||
|
|
|
||
|
|
void TinyGPS::crack_datetime(int *year, byte *month, byte *day,
|
||
|
|
byte *hour, byte *minute, byte *second, byte *hundredths, unsigned long *age)
|
||
|
|
{
|
||
|
|
unsigned long date, time;
|
||
|
|
get_datetime(&date, &time, age);
|
||
|
|
if (year)
|
||
|
|
{
|
||
|
|
*year = date % 100;
|
||
|
|
*year += *year > 80 ? 1900 : 2000;
|
||
|
|
}
|
||
|
|
if (month) *month = (date / 100) % 100;
|
||
|
|
if (day) *day = date / 10000;
|
||
|
|
if (hour) *hour = time / 1000000;
|
||
|
|
if (minute) *minute = (time / 10000) % 100;
|
||
|
|
if (second) *second = (time / 100) % 100;
|
||
|
|
if (hundredths) *hundredths = time % 100;
|
||
|
|
}
|
||
|
|
|
||
|
|
float TinyGPS::f_altitude()
|
||
|
|
{
|
||
|
|
return _altitude == GPS_INVALID_ALTITUDE ? GPS_INVALID_F_ALTITUDE : _altitude / 100.0;
|
||
|
|
}
|
||
|
|
|
||
|
|
float TinyGPS::f_course()
|
||
|
|
{
|
||
|
|
return _course == GPS_INVALID_ANGLE ? GPS_INVALID_F_ANGLE : _course / 100.0;
|
||
|
|
}
|
||
|
|
|
||
|
|
float TinyGPS::f_speed_knots()
|
||
|
|
{
|
||
|
|
return _speed == GPS_INVALID_SPEED ? GPS_INVALID_F_SPEED : _speed / 100.0;
|
||
|
|
}
|
||
|
|
|
||
|
|
float TinyGPS::f_speed_mph()
|
||
|
|
{
|
||
|
|
float sk = f_speed_knots();
|
||
|
|
return sk == GPS_INVALID_F_SPEED ? GPS_INVALID_F_SPEED : _GPS_MPH_PER_KNOT * f_speed_knots();
|
||
|
|
}
|
||
|
|
|
||
|
|
float TinyGPS::f_speed_mps()
|
||
|
|
{
|
||
|
|
float sk = f_speed_knots();
|
||
|
|
return sk == GPS_INVALID_F_SPEED ? GPS_INVALID_F_SPEED : _GPS_MPS_PER_KNOT * f_speed_knots();
|
||
|
|
}
|
||
|
|
|
||
|
|
float TinyGPS::f_speed_kmph()
|
||
|
|
{
|
||
|
|
float sk = f_speed_knots();
|
||
|
|
return sk == GPS_INVALID_F_SPEED ? GPS_INVALID_F_SPEED : _GPS_KMPH_PER_KNOT * f_speed_knots();
|
||
|
|
}
|
||
|
|
|
||
|
|
const float TinyGPS::GPS_INVALID_F_ANGLE = 1000.0;
|
||
|
|
const float TinyGPS::GPS_INVALID_F_ALTITUDE = 1000000.0;
|
||
|
|
const float TinyGPS::GPS_INVALID_F_SPEED = -1.0;
|