David Spillman / GPS2

Updated version with new commands and sleep mode

Fork of GPS by Sam Clarke

GPS.cpp@6:af055728e564, 2015-04-05 (annotated)

Committer:
Spilly
Date:
Sun Apr 05 01:41:34 2015 +0000
Revision:
6:af055728e564
Parent:
5:96d5736d9613
Child:
7:7aac669b0075
Added several new initialization commands and a sleep function

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Spilly 6:af055728e564 1 /**************************************************************************************************************************************************************
Spilly 6:af055728e564 2 // This is a modified version of mbed /users/SamClarke/code/GPS/ for MTK3339 GPS module
Spilly 6:af055728e564 3 //
Spilly 6:af055728e564 4 // Changes made by Ryan Spillman:
Spilly 6:af055728e564 5 // added commands to the initialization function to set baud rate, set update rate, enabled DGPS WAAS, and set minimum navigation speed
Spilly 6:af055728e564 6 // added a function to put the unit into sleep mode
Spilly 6:af055728e564 7 // added several zeros after the decimal places to fix weird rounding errors
Spilly 6:af055728e564 8 // added information about checksums
Spilly 6:af055728e564 9 //
Spilly 6:af055728e564 10 // IMPORTANT:
Spilly 6:af055728e564 11 // Any changes made to commands sent to GPS unit require corresponding changes to the
Spilly 6:af055728e564 12 // checksum at the end of the command
Spilly 6:af055728e564 13 // Here is a tool for calculating the checksum:
Spilly 6:af055728e564 14 // http://siliconsparrow.com/demos/nmeachecksum.php
Spilly 6:af055728e564 15 **************************************************************************************************************************************************************/
Spilly 6:af055728e564 16
SamClarke 1:0a034c2dbea6 17 #include "GPS.h"
SamClarke 1:0a034c2dbea6 18 GPS::GPS(PinName tx, PinName rx) : _UltimateGps(tx, rx)
SamClarke 1:0a034c2dbea6 19 {
Spilly 6:af055728e564 20 //_UltimateGps.baud(9600); //use this for default MTK3339 adafruit firmware
Spilly 6:af055728e564 21 _UltimateGps.baud(38400); //Changed firmware of MTK3339 to 38400 baud with update rate of 5Hz (GlobalTopFlashTool to change firmware)
SamClarke 1:0a034c2dbea6 22 }
SamClarke 1:0a034c2dbea6 23
SamClarke 1:0a034c2dbea6 24 int GPS::parseData()
SamClarke 1:0a034c2dbea6 25 {
SamClarke 1:0a034c2dbea6 26 while(1) {
SamClarke 1:0a034c2dbea6 27 getData();
SamClarke 1:0a034c2dbea6 28 if(sscanf(NEMA, "GPGGA, %*f, %*f, %*c, %*f, %*c, %d, %d, %*f, %f", &fixtype, &satellites, &altitude) >=1);
SamClarke 4:9ac674d05370 29 if(sscanf(NEMA, "GPRMC, %2d%2d%f, %c, %f, %c, %f, %c, %f, %f, %2d%2d%2d", &hours, &minutes, &seconds, &validity, &latitude, &ns, &longitude, &ew, &speed, &heading, &day, &month, &year) >=1) {
SamClarke 1:0a034c2dbea6 30 if(fixtype == 0) {
SamClarke 1:0a034c2dbea6 31 return 0;
SamClarke 1:0a034c2dbea6 32 }
SamClarke 4:9ac674d05370 33 year += 2000;
SamClarke 1:0a034c2dbea6 34 if(ns =='S') {
Spilly 6:af055728e564 35 latitude *= -1.00000000000000000f;
SamClarke 1:0a034c2dbea6 36 }
SamClarke 1:0a034c2dbea6 37 if(ew =='W') {
Spilly 6:af055728e564 38 longitude *= -1.00000000000000000f;
SamClarke 1:0a034c2dbea6 39 }
Spilly 6:af055728e564 40 float degrees = trunc(latitude / 100.0000000000000000f);
Spilly 6:af055728e564 41 float minutes = latitude - (degrees * 100.00000000000000000f);
Spilly 6:af055728e564 42 latitude = degrees + minutes / 60.00000000000000000f;
Spilly 6:af055728e564 43 degrees = trunc(longitude / 100.0000000000000000f);
Spilly 6:af055728e564 44 minutes = longitude - (degrees * 100.00000000000000000f);
Spilly 6:af055728e564 45 longitude = degrees + minutes / 60.00000000000000000f;
SamClarke 3:5cb504ce2793 46 if(fixtype == 1) {
SamClarke 3:5cb504ce2793 47 fix = "Positive";
SamClarke 3:5cb504ce2793 48 }
SamClarke 3:5cb504ce2793 49 if(fixtype == 2) {
SamClarke 3:5cb504ce2793 50 fix = "Differential";
SamClarke 3:5cb504ce2793 51 }
Spilly 6:af055728e564 52 if(heading > 0.00f && heading < 45.00f) {
SamClarke 3:5cb504ce2793 53 cardinal = "NNE";
SamClarke 3:5cb504ce2793 54 }
Spilly 6:af055728e564 55 if(heading == 45.00f) {
SamClarke 3:5cb504ce2793 56 cardinal = "NE";
SamClarke 3:5cb504ce2793 57 }
Spilly 6:af055728e564 58 if(heading > 45.00f && heading < 90.00f) {
SamClarke 3:5cb504ce2793 59 cardinal = "ENE";
SamClarke 3:5cb504ce2793 60 }
Spilly 6:af055728e564 61 if(heading == 90.00f) {
SamClarke 3:5cb504ce2793 62 cardinal = "E";
SamClarke 3:5cb504ce2793 63 }
Spilly 6:af055728e564 64 if(heading > 90.00f && heading < 135.00f) {
SamClarke 3:5cb504ce2793 65 cardinal = "ESE";
SamClarke 3:5cb504ce2793 66 }
Spilly 6:af055728e564 67 if(heading == 135.00f) {
SamClarke 3:5cb504ce2793 68 cardinal = "SE";
SamClarke 3:5cb504ce2793 69 }
Spilly 6:af055728e564 70 if(heading > 135.00f && heading < 180.00f) {
SamClarke 3:5cb504ce2793 71 cardinal = "SSE";
SamClarke 3:5cb504ce2793 72 }
Spilly 6:af055728e564 73 if(heading == 180.00f) {
SamClarke 3:5cb504ce2793 74 cardinal = "S";
SamClarke 3:5cb504ce2793 75 }
Spilly 6:af055728e564 76 if(heading > 180.00f && heading < 225.00f) {
SamClarke 3:5cb504ce2793 77 cardinal = "SSW";
SamClarke 3:5cb504ce2793 78 }
Spilly 6:af055728e564 79 if(heading == 225.00f) {
SamClarke 3:5cb504ce2793 80 cardinal = "SW";
SamClarke 3:5cb504ce2793 81 }
Spilly 6:af055728e564 82 if(heading > 225.00f && heading < 270.00f) {
SamClarke 3:5cb504ce2793 83 cardinal = "WSW";
SamClarke 3:5cb504ce2793 84 }
Spilly 6:af055728e564 85 if(heading == 270.00f) {
SamClarke 3:5cb504ce2793 86 cardinal = "W";
SamClarke 3:5cb504ce2793 87 }
Spilly 6:af055728e564 88 if(heading > 270.00f && heading < 315.00f) {
SamClarke 3:5cb504ce2793 89 cardinal = "WNW";
SamClarke 3:5cb504ce2793 90 }
Spilly 6:af055728e564 91 if(heading == 315.00f) {
SamClarke 3:5cb504ce2793 92 cardinal = "NW";
SamClarke 3:5cb504ce2793 93 }
Spilly 6:af055728e564 94 if(heading > 315.00f && heading < 360.00f) {
SamClarke 3:5cb504ce2793 95 cardinal = "NNW";
SamClarke 3:5cb504ce2793 96 }
Spilly 6:af055728e564 97 if(heading == 360.00f || heading == 0.00f) {
SamClarke 3:5cb504ce2793 98 cardinal = "N";
SamClarke 3:5cb504ce2793 99 }
Spilly 6:af055728e564 100 kph = speed*1.852f;
SamClarke 1:0a034c2dbea6 101 return 1;
SamClarke 1:0a034c2dbea6 102 }
SamClarke 1:0a034c2dbea6 103 }
SamClarke 1:0a034c2dbea6 104 }
SamClarke 1:0a034c2dbea6 105
SamClarke 1:0a034c2dbea6 106
SamClarke 1:0a034c2dbea6 107 float GPS::trunc(float v)
SamClarke 1:0a034c2dbea6 108 {
Spilly 6:af055728e564 109 if(v < 0.0f) {
Spilly 6:af055728e564 110 v*= -1.0f;
SamClarke 1:0a034c2dbea6 111 v = floor(v);
Spilly 6:af055728e564 112 v*=-1.0f;
SamClarke 1:0a034c2dbea6 113 } else {
SamClarke 1:0a034c2dbea6 114 v = floor(v);
SamClarke 1:0a034c2dbea6 115 }
SamClarke 1:0a034c2dbea6 116 return v;
SamClarke 1:0a034c2dbea6 117 }
SamClarke 1:0a034c2dbea6 118
SamClarke 1:0a034c2dbea6 119 void GPS::getData()
SamClarke 1:0a034c2dbea6 120 {
SamClarke 1:0a034c2dbea6 121 while(_UltimateGps.getc() != '$');
SamClarke 1:0a034c2dbea6 122 for(int i=0; i<256; i++) {
SamClarke 1:0a034c2dbea6 123 NEMA[i] = _UltimateGps.getc();
SamClarke 1:0a034c2dbea6 124 if(NEMA[i] == '\r') {
SamClarke 1:0a034c2dbea6 125 NEMA[i] = 0;
SamClarke 1:0a034c2dbea6 126 return;
SamClarke 1:0a034c2dbea6 127 }
SamClarke 1:0a034c2dbea6 128 }
SamClarke 1:0a034c2dbea6 129 error("overflowed message limit");
SamClarke 1:0a034c2dbea6 130 }
SamClarke 1:0a034c2dbea6 131
SamClarke 1:0a034c2dbea6 132 void GPS::Init()
SamClarke 1:0a034c2dbea6 133 {
Spilly 6:af055728e564 134 _UltimateGps.printf("$PMTK251,38400*27\r\n"); //set baud (any higher and the serial buffer overflows)
Spilly 6:af055728e564 135 //_UltimateGps.printf("$PMTK220,100*2F\r\n"); //10 Hz update
Spilly 6:af055728e564 136 _UltimateGps.printf("$PMTK220,200*2C\r\n"); //5 Hz udpate
Spilly 6:af055728e564 137 _UltimateGps.printf("$PMTK225,0*2bt\r\n"); //disable always locate (datasheet indicates that this negatively affects accuracy)
Spilly 6:af055728e564 138 _UltimateGps.printf("$PMTK301,2*2et\r\n"); //set DGPS to use WAAS
Spilly 6:af055728e564 139 _UltimateGps.printf("$PMTK386,0.8*35\r\n"); //set Nav Speed threshold to 0.8 m/s
Spilly 6:af055728e564 140 _UltimateGps.printf("$PMTK314,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*28\r\n");
Spilly 6:af055728e564 141 }
Spilly 6:af055728e564 142
Spilly 6:af055728e564 143 void GPS::Sleep(int sleep)
Spilly 6:af055728e564 144 {
Spilly 6:af055728e564 145 if(sleep == 1)
Spilly 6:af055728e564 146 {
Spilly 6:af055728e564 147 _UltimateGps.printf("$$PMTK161,0*28\r\n"); //go to sleep
Spilly 6:af055728e564 148 }
Spilly 6:af055728e564 149 else
Spilly 6:af055728e564 150 {
Spilly 6:af055728e564 151 _UltimateGps.printf("$$PMTK161,1*28\r\n"); //wake up
Spilly 6:af055728e564 152 _UltimateGps.printf("$PMTK220,200*2C\r\n"); //5 Hz udpate
SamClarke 1:0a034c2dbea6 153 _UltimateGps.printf("$PMTK314,0,1,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*28\r\n");
Spilly 6:af055728e564 154 }
SamClarke 1:0a034c2dbea6 155 }