eunkyoung kim / GPS

wrong calculation of longitude

Dependents:   GPS_HelloWorld GPS_Buzzer_Alert_Helloworld Twitter_GPS_Web_Client_WIZwiki-W7500

Fork of GPS by Boris Adryan

GPS.cpp@2:e2b8d86abee3, 2015-07-27 (annotated)

Committer:
eunkyoungkim
Date:
Mon Jul 27 04:55:38 2015 +0000
Revision:
2:e2b8d86abee3
Parent:
1:1d60e6a0ffd9 
wrong calculation value of longitude

Who changed what in which revision?

UserRevisionLine numberNew contents of line
8fromPi 1:1d60e6a0ffd9 1 /* mbed GPS Module Library
simon 0:15611c7938a3 2 * Copyright (c) 2008-2010, sford
8fromPi 1:1d60e6a0ffd9 3 * Copyright (c) 2013, B.Adryan
simon 0:15611c7938a3 4 *
simon 0:15611c7938a3 5 * Permission is hereby granted, free of charge, to any person obtaining a copy
simon 0:15611c7938a3 6 * of this software and associated documentation files (the "Software"), to deal
simon 0:15611c7938a3 7 * in the Software without restriction, including without limitation the rights
simon 0:15611c7938a3 8 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
simon 0:15611c7938a3 9 * copies of the Software, and to permit persons to whom the Software is
simon 0:15611c7938a3 10 * furnished to do so, subject to the following conditions:
simon 0:15611c7938a3 11 *
simon 0:15611c7938a3 12 * The above copyright notice and this permission notice shall be included in
simon 0:15611c7938a3 13 * all copies or substantial portions of the Software.
simon 0:15611c7938a3 14 *
simon 0:15611c7938a3 15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
simon 0:15611c7938a3 16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
simon 0:15611c7938a3 17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
simon 0:15611c7938a3 18 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
simon 0:15611c7938a3 19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
simon 0:15611c7938a3 20 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
simon 0:15611c7938a3 21 * THE SOFTWARE.
simon 0:15611c7938a3 22 */
simon 0:15611c7938a3 23
simon 0:15611c7938a3 24 #include "GPS.h"
simon 0:15611c7938a3 25
8fromPi 1:1d60e6a0ffd9 26 GPS::GPS(PinName tx, PinName rx, int Baud) : _gps(tx, rx) {
8fromPi 1:1d60e6a0ffd9 27 _gps.baud(Baud);
simon 0:15611c7938a3 28 longitude = 0.0;
simon 0:15611c7938a3 29 latitude = 0.0;
simon 0:15611c7938a3 30 }
simon 0:15611c7938a3 31
simon 0:15611c7938a3 32 int GPS::sample() {
8fromPi 1:1d60e6a0ffd9 33 char ns, ew, unit;
simon 0:15611c7938a3 34 int lock;
simon 0:15611c7938a3 35
simon 0:15611c7938a3 36 while(1) {
simon 0:15611c7938a3 37 getline();
simon 0:15611c7938a3 38
simon 0:15611c7938a3 39 // Check if it is a GPGGA msg (matches both locked and non-locked msg)
8fromPi 1:1d60e6a0ffd9 40 if(sscanf(msg, "GPGGA,%f,%f,%c,%f,%c,%d,%d,%f,%f,%c,%f", &time, &latitude, &ns, &longitude, &ew, &lock, &sats, &hdop, &alt, &unit, &geoid) >= 1) {
simon 0:15611c7938a3 41 if(!lock) {
8fromPi 1:1d60e6a0ffd9 42 time = 0.0;
simon 0:15611c7938a3 43 longitude = 0.0;
8fromPi 1:1d60e6a0ffd9 44 latitude = 0.0;
8fromPi 1:1d60e6a0ffd9 45 sats = 0;
8fromPi 1:1d60e6a0ffd9 46 hdop = 0.0;
8fromPi 1:1d60e6a0ffd9 47 alt = 0.0;
8fromPi 1:1d60e6a0ffd9 48 geoid = 0.0;
simon 0:15611c7938a3 49 return 0;
simon 0:15611c7938a3 50 } else {
8fromPi 1:1d60e6a0ffd9 51 //GPGGA format according http://aprs.gids.nl/nmea/#gga
8fromPi 1:1d60e6a0ffd9 52 // time (float), lat (f), (N/S) (c), long (f), (E/W) (c), fix (d), sats (d),
8fromPi 1:1d60e6a0ffd9 53 // hdop (float), altitude (float), M, geoid (float), M, , ,
8fromPi 1:1d60e6a0ffd9 54 //GPGGA,092010.000,5210.9546,N,00008.8913,E,1,07,1.3,9.7,M,47.0,M,,0000*5D
8fromPi 1:1d60e6a0ffd9 55
simon 0:15611c7938a3 56 if(ns == 'S') { latitude *= -1.0; }
simon 0:15611c7938a3 57 if(ew == 'W') { longitude *= -1.0; }
simon 0:15611c7938a3 58 float degrees = trunc(latitude / 100.0f);
simon 0:15611c7938a3 59 float minutes = latitude - (degrees * 100.0f);
simon 0:15611c7938a3 60 latitude = degrees + minutes / 60.0f;
eunkyoungkim 2:e2b8d86abee3 61 degrees = trunc(longitude / 100.0f);// * 0.01f);
simon 0:15611c7938a3 62 minutes = longitude - (degrees * 100.0f);
simon 0:15611c7938a3 63 longitude = degrees + minutes / 60.0f;
simon 0:15611c7938a3 64 return 1;
simon 0:15611c7938a3 65 }
simon 0:15611c7938a3 66 }
simon 0:15611c7938a3 67 }
simon 0:15611c7938a3 68 }
simon 0:15611c7938a3 69
simon 0:15611c7938a3 70 float GPS::trunc(float v) {
simon 0:15611c7938a3 71 if(v < 0.0) {
simon 0:15611c7938a3 72 v*= -1.0;
simon 0:15611c7938a3 73 v = floor(v);
simon 0:15611c7938a3 74 v*=-1.0;
simon 0:15611c7938a3 75 } else {
simon 0:15611c7938a3 76 v = floor(v);
simon 0:15611c7938a3 77 }
simon 0:15611c7938a3 78 return v;
simon 0:15611c7938a3 79 }
simon 0:15611c7938a3 80
simon 0:15611c7938a3 81 void GPS::getline() {
simon 0:15611c7938a3 82 while(_gps.getc() != '$'); // wait for the start of a line
simon 0:15611c7938a3 83 for(int i=0; i<256; i++) {
simon 0:15611c7938a3 84 msg[i] = _gps.getc();
simon 0:15611c7938a3 85 if(msg[i] == '\r') {
simon 0:15611c7938a3 86 msg[i] = 0;
simon 0:15611c7938a3 87 return;
simon 0:15611c7938a3 88 }
simon 0:15611c7938a3 89 }
simon 0:15611c7938a3 90 error("Overflowed message limit");
8fromPi 1:1d60e6a0ffd9 91 }