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direwolf/nmea.c

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//
// This file is part of Dire Wolf, an amateur radio packet TNC.
//
// Copyright (C) 2014 John Langner, WB2OSZ
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
//
//#define DEBUG 1
/*------------------------------------------------------------------
*
* Module: nmea.c
*
* Purpose: Receive NMEA sentences from a GPS receiver.
* Send NMEA waypoint sentences to GPS display or mapping application.
*
*---------------------------------------------------------------*/
#include <stdio.h>
#include <unistd.h>
#if __WIN32__
#include <stdlib.h>
#include <windows.h>
#else
#define __USE_XOPEN2KXSI 1
#define __USE_XOPEN 1
//#define __USE_POSIX 1
#include <stdlib.h>
#include <ctype.h>
#include <fcntl.h>
#include <termios.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/errno.h>
#endif
#include <assert.h>
#include <string.h>
#if __WIN32__
char *strsep(char **stringp, const char *delim);
#endif
#include "direwolf.h"
#include "config.h"
#include "ax25_pad.h"
#include "textcolor.h"
//#include "xmit.h"
#include "latlong.h"
#include "nmea.h"
#include "grm_sym.h" /* Garmin symbols */
#include "mgn_icon.h" /* Magellan icons */
#if __WIN32__
typedef HANDLE MYFDTYPE;
#define MYFDERROR INVALID_HANDLE_VALUE
#else
typedef int MYFDTYPE;
#define MYFDERROR (-1)
#endif
// TODO: receive buffer... static kiss_frame_t kf; /* Accumulated KISS frame and state of decoder. */
static MYFDTYPE nmea_port_fd = MYFDERROR;
static void nmea_send_sentence (char *sent);
#if __WIN32__
static unsigned __stdcall nmea_listen_thread (void *arg);
#else
static void * nmea_listen_thread (void *arg);
#endif
static void nmea_parse_gps (char *sentence);
static int nmea_debug = 0; /* Print information flowing from and to attached device. */
void nmea_set_debug (int n)
{
nmea_debug = n;
}
/*-------------------------------------------------------------------
*
* Name: nmea_init
*
* Purpose: Initialization for NMEA communication port.
&
* Inputs: mc->nmea_port - name of serial port.
*
* Global output: nmea_port_fd
*
*
* Description: (1) Open serial port device.
* (2) Start a new thread to listen for GPS receiver.
*
* Reference: http://www.robbayer.com/files/serial-win.pdf
*
*---------------------------------------------------------------*/
static MYFDTYPE nmea_open_port (char *device);
void nmea_init (struct misc_config_s *mc)
{
#if __WIN32__
HANDLE nmea_listen_th;
#else
pthread_t nmea_listen_tid;
#endif
/*
* Open serial port connection.
*/
if (strlen(mc->nmea_port) > 0) {
#if ! __WIN32__
/* Translate Windows device name into Linux name. */
/* COM1 -> /dev/ttyS0, etc. */
if (strncasecmp(mc->nmea_port, "COM", 3) == 0) {
int n = atoi (mc->nmea_port + 3);
text_color_set(DW_COLOR_INFO);
dw_printf ("Converted NMEA device '%s'", mc->nmea_port);
if (n < 1) n = 1;
sprintf (mc->nmea_port, "/dev/ttyS%d", n-1);
dw_printf (" to Linux equivalent '%s'\n", mc->nmea_port);
}
#endif
nmea_port_fd = nmea_open_port (mc->nmea_port);
if (nmea_port_fd != MYFDERROR) {
#if __WIN32__
nmea_listen_th = (HANDLE)_beginthreadex (NULL, 0, nmea_listen_thread, (void*)(long)nmea_port_fd, 0, NULL);
if (nmea_listen_th == NULL) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("Could not create NMEA listening thread.\n");
return;
}
#else
int e;
e = pthread_create (&nmea_listen_tid, NULL, nmea_listen_thread, (void*)(long)nmea_port_fd);
if (e != 0) {
text_color_set(DW_COLOR_ERROR);
perror("Could not create NMEA listening thread.");
}
#endif
}
}
#if DEBUG
text_color_set (DW_COLOR_DEBUG);
dw_printf ("end of nmea_init: nmea_port_fd = %d\n", nmea_port_fd);
#endif
}
/*
* Returns fd for serial port or MYFDERROR for error.
*/
static MYFDTYPE nmea_open_port (char *devicename)
{
#if __WIN32__
MYFDTYPE fd;
DCB dcb;
int ok;
char bettername[50];
#if DEBUG
text_color_set(DW_COLOR_DEBUG);
dw_printf ("nmea_open_port ( '%s' )\n", devicename);
#endif
// Need to use FILE_FLAG_OVERLAPPED for full duplex operation.
// Without it, write blocks when waiting on read.
// Read http://support.microsoft.com/kb/156932
// Bug fix in release 1.1 - Need to munge name for COM10 and up.
// http://support.microsoft.com/kb/115831
strcpy (bettername, devicename);
if (strncasecmp(devicename, "COM", 3) == 0) {
int n;
n = atoi(devicename+3);
if (n >= 10) {
strcpy (bettername, "\\\\.\\");
strcat (bettername, devicename);
}
}
fd = CreateFile(bettername, GENERIC_READ | GENERIC_WRITE,
0, NULL, OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL);
if (fd == MYFDERROR) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("ERROR - Could not open NMEA port %s.\n", devicename);
return (MYFDERROR);
}
/* Reference: http://msdn.microsoft.com/en-us/library/windows/desktop/aa363201(v=vs.85).aspx */
memset (&dcb, 0, sizeof(dcb));
dcb.DCBlength = sizeof(DCB);
ok = GetCommState (fd, &dcb);
if (! ok) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("nmea_open_port: GetCommState failed.\n");
}
/* http://msdn.microsoft.com/en-us/library/windows/desktop/aa363214(v=vs.85).aspx */
dcb.DCBlength = sizeof(DCB);
dcb.BaudRate = CBR_4800;
dcb.fBinary = 1;
dcb.fParity = 0;
dcb.fOutxCtsFlow = 0;
dcb.fOutxDsrFlow = 0;
dcb.fDtrControl = DTR_CONTROL_DISABLE;
dcb.fDsrSensitivity = 0;
dcb.fOutX = 0;
dcb.fInX = 0;
dcb.fErrorChar = 0;
dcb.fNull = 0; /* Don't drop nul characters! */
dcb.fRtsControl = 0;
dcb.ByteSize = 8;
dcb.Parity = NOPARITY;
dcb.StopBits = ONESTOPBIT;
ok = SetCommState (fd, &dcb);
if (! ok) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("nmea_open_port: SetCommState failed.\n");
}
text_color_set(DW_COLOR_INFO);
dw_printf("NMEA communication started on %s.\n", devicename);
#else
/* Linux version. */
int fd;
struct termios ts;
int e;
#if DEBUG
text_color_set(DW_COLOR_DEBUG);
dw_printf ("nmea_open_port ( '%s' )\n", devicename);
#endif
fd = open (devicename, O_RDWR);
if (fd == MYFDERROR) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("ERROR - Could not open NMEA port %s.\n", devicename);
return (MYFDERROR);
}
e = tcgetattr (fd, &ts);
if (e != 0) { perror ("nm tcgetattr"); }
cfmakeraw (&ts);
ts.c_cc[VMIN] = 1; /* wait for at least one character */
ts.c_cc[VTIME] = 0; /* no fancy timing. */
cfsetispeed (&ts, B4800);
cfsetospeed (&ts, B4800);
e = tcsetattr (fd, TCSANOW, &ts);
if (e != 0) { perror ("nmea tcsetattr"); }
text_color_set(DW_COLOR_INFO);
dw_printf("NMEA communication started on %s.\n", devicename);
#endif
return (fd);
}
/*-------------------------------------------------------------------
*
* Name: append_checksum
*
* Purpose: Append checksum to the sentence.
*
* In/out: sentence - NMEA sentence beginning with '$'.
*
* Description: Checksum is exclusive of characters except leading '$'.
* We append '*' and an upper case two hexadecimal value.
*
*--------------------------------------------------------------------*/
static void append_checksum (char *sentence)
{
char *p;
int cs;
assert (sentence[0] == '$');
cs = 0;
for (p = sentence+1; *p != '\0'; p++) {
cs ^= *p;
}
sprintf (p, "*%02X", cs & 0xff);
// Add crlf too?
} /* end append_checksum */
/*-------------------------------------------------------------------
*
* Name: nema_send_waypoint
*
* Purpose: Convert APRS position or object into NMEA waypoint sentence
* for use by a GPS display or other mapping application.
*
* Inputs: wname_in - Name of waypoint.
* dlat - Latitude.
* dlong - Longitude.
* symtab - Symbol table or overlay character.
* symbol - Symbol code.
* alt - Altitude in meters or G_UNKOWN.
* course - Course in degrees or ??? for unknown.
* speed - Speed in knots ?? or ??
* comment - Description or message.
*
*
* Description: Currently we send multiple styles. Maybe someday there might
* be an option to send a selected subset.
*
* $GPWPL - Generic with only location and name.
* $PGRMW - Garmin, adds altitude, symbol, and comment
* to previously named waypoint.
* $PMGNWPL - Magellan, more complete for stationary objects.
* $PKWDWPL - Kenwood with APRS style symbol but missing comment.
*
*--------------------------------------------------------------------*/
void nmea_send_waypoint (char *wname_in, double dlat, double dlong, char symtab, char symbol,
float alt, float course, float speed, char *comment)
{
char wname[12]; /* Waypoint name. Any , or * removed. */
char slat[12]; /* DDMM.mmmm */
char slat_ns[2]; /* N or S */
char slong[12]; /* DDDMM.mmmm */
char slong_ew[2]; /* E or W */
char sentence[500];
char salt[12]; /* altitude as string, empty if unknown */
char sspeed[12]; /* speed as string, empty if unknown */
char scourse[12]; /* course as string, empty if unknown */
int grm_sym; /* Garmin symbol code. */
char sicon[4]; /* Magellan icon string */
char stime[8];
char sdate[8];
char *p;
// Remove any comma from name.
// TODO: remove any , or * from comment.
strcpy (wname, wname_in);
for (p=wname; *p != '\0'; p++) {
if (*p == ',') *p = ' ';
if (*p == '*') *p = ' ';
}
// Convert position to character form.
latitude_to_nmea (dlat, slat, slat_ns);
longitude_to_nmea (dlong, slong, slong_ew);
/*
* Generic.
*
* $GPWPL,ddmm.mmmm,ns,dddmm.mmmm,ew,wname*99
*
* Where,
* ddmm.mmmm,ns is latitude
* dddmm.mmmm,ew is longitude
* wname is the waypoint name
* *99 is checksum
*/
sprintf (sentence, "$GPWPL,%s,%s,%s,%s,%s", slat, slat_ns, slong, slong_ew, wname);
append_checksum (sentence);
nmea_send_sentence (sentence);
/*
* Garmin - https://www8.garmin.com/support/pdf/NMEA_0183.pdf
* http://gpsinformation.net/mag-proto.htm
*
* $PGRMW,wname,alt,symbol,comment*99
*
* Where,
*
* wname is waypoint name. Must match existing waypoint.
* alt is altitude in meters.
* symbol is symbol code. Hexadecimal up to FFFF.
* See Garmin Device Interface Specification 001-0063-00.
* comment is comment for the waypoint.
* *99 is checksum
*/
if (alt == G_UNKNOWN) {
strcpy (salt, "");
}
else {
sprintf (salt, "%.1f", alt);
}
grm_sym = 0x1234; // TODO
sprintf (sentence, "$PGRMW,%s,%s,%04X,%s", wname, salt, grm_sym, comment);
append_checksum (sentence);
nmea_send_sentence (sentence);
/*
* Magellan - http://www.gpsinformation.org/mag-proto-2-11.pdf
*
* $PMGNWPL,ddmm.mmmm,ns,dddmm.mmmm,ew,alt,unit,wname,comment,icon,xx*99
*
* Where,
* ddmm.mmmm,ns is latitude
* dddmm.mmmm,ew is longitude
* alt is altitude
* unit is M for meters or F for feet
* wname is the waypoint name
* comment is message or comment
* icon is one or two letters for icon code
* xx is waypoint type which is optional, not well
* defined, and not used in their example.
* *99 is checksum
*/
// TODO: icon
sprintf (sicon, "??");
sprintf (sentence, "$PMGNWPL,%s,%s,%s,%s,%s,M,%s,%s,%s",
slat, slat_ns, slong, slong_ew, salt, wname, comment, sicon);
append_checksum (sentence);
nmea_send_sentence (sentence);
/*
* Kenwood - Speculation due to no official spec found so far.
*
* $PKWDWPL,hhmmss,v,ddmm.mmmm,ns,dddmm.mmmm,ew,speed,course,ddmmyy,alt,wname,ts*99
*
* Where,
* hhmmss is time in UTC. Should we supply current
* time or only pass along time from
* received signal?
* v indicates valid data ?????????????????
* Why would we send if not valid?
* ddmm.mmmm,ns is latitude
* dddmm.mmmm,ew is longitude
* speed is speed in UNITS ??? knots ?????
* course is course in degrees
* ddmmyy is date. Same question as time.
* alt is altitude. in UNITS ??? meters ???
* wname is the waypoint name
* ts are the table and symbol.
* Non-standard parsing would be required
* to deal with these for symbol:
* , Boy Scouts / Girl Scouts
* * SnowMobile / Snow
* *99 is checksum
*
* Oddly, there is not place for comment.
*/
if (speed == G_UNKNOWN) {
strcpy (sspeed, "");
}
else {
sprintf (sspeed, "%.1f", speed);
}
if (course == G_UNKNOWN) {
strcpy (scourse, "");
}
else {
sprintf (scourse, "%.1f", course);
}
// TODO: how to handle time & date ???
strcpy (stime, "123456");
strcpy (sdate, "123456");
sprintf (sentence, "$PKWDWPL,%s,V,%s,%s,%s,%s,%s,%s,%s,%s,%s,%c%c",
stime, slat, slat_ns, slong, slong_ew,
sspeed, scourse, sdate, salt, wname, symtab, symbol);
append_checksum (sentence);
nmea_send_sentence (sentence);
/*
* One application recognizes these. Not implemented at this time.
*
* $GPTLL,01,ddmm.mmmm,ns,dddmm.mmmm,ew,tname,000000.00,T,R*99
*
* Where,
* ddmm.mmmm,ns is latitude
* dddmm.mmmm,ew is longitude
* tname is the target name
* 000000.00 is timestamp ???
* T is target status (S for need help)
* R is reference target ???
* *99 is checksum
*
*
* $GPTXT,01,01,tname,message*99
*
* Where,
*
* 01 is total number of messages in transmission
* 01 is message number in this transmission
* tname is target name. Should match name in WPL or TTL.
* message is the message.
* *99 is checksum
*
*/
} /* end nmea_send_waypoint */
#if 0
* d710a menu 603 $GPWPL $PMGNWPL $PKWDWPL
symbol mapping
https://freepository.com:444/50lItuLQ7fW6s-web/browser/Tracker2/trunk/sources/waypoint.c?rev=108
Data Transmission Protocol For Magellan Products <20> version 2.11
$PMGNWPL,4651.529,N,07111.425,W,0000000,M,GC5A5F, GC. The straight line,a*13
$PMGNWPL,3549.499,N,08650.827,W,0000257,M,HOME,HOME,c*4D
http://gpsbabel.sourcearchive.com/documentation/1.3.7~cvs1/magproto_8c-source.html
sscanf(trkmsg,"$PMGNWPL,%lf,%c,%lf,%c,%d,%c,%[^,],%[^,]",
&latdeg,&latdir,
&lngdeg,&lngdir,
&alt,&altunits,shortname,descr); then icon
sprintf(obuf, "PMGNWPL,%4.3f,%c,%09.3f,%c,%07.0f,M,%-.*s,%-.46s,%s",
lat, ilat < 0 ? 'S' : 'N',
lon, ilon < 0 ? 'W' : 'E',
waypointp->altitude == unknown_alt ?
0 : waypointp->altitude,
wpt_len,
owpt,
odesc,
icon_token);
https://freepository.com:444/50lItuLQ7fW6s-web/changeset/108/Tracker2/trunk/sources/waypoint.c
$PMGNWPL,4106.003,S,14640.214,E,0000069,M,KISSING SPOT,,a*3C
*
https://freepository.com:444/50lItuLQ7fW6s-web/changeset/325
#endif
static void nmea_send_sentence (char *sent)
{
int err;
int len = strlen(sent);
if (nmea_port_fd == MYFDERROR) {
return;
}
text_color_set(DW_COLOR_XMIT);
dw_printf ("%s\n", sent);
if (nmea_debug) {
// TODO: debugg out... nmea_debug_print (TO_CLIENT, NULL, nmea_buff+1, nmea_len-2);
}
// TODO: need to append CR LF.
#if __WIN32__
DWORD nwritten;
/* Without this, write blocks while we are waiting on a read. */
static OVERLAPPED ov_wr;
memset (&ov_wr, 0, sizeof(ov_wr));
if ( ! WriteFile (nmea_port_fd, sent, len, &nwritten, &ov_wr))
{
err = GetLastError();
if (err != ERROR_IO_PENDING)
{
text_color_set(DW_COLOR_ERROR);
dw_printf ("\nError sending NMEA sentence. Error %d.\n\n", (int)GetLastError());
//CloseHandle (nmea_port_fd);
//nmea_port_fd = MYFDERROR;
}
}
else if (nwritten != len)
{
text_color_set(DW_COLOR_ERROR);
dw_printf ("\nError sending NMEA sentence. Only %d of %d written.\n\n", (int)nwritten, len);
//CloseHandle (nmea_port_fd);
//nmea_port_fd = MYFDERROR;
}
#else
err = write (nmea_port_fd, sent, (size_t)len);
if (err != len)
{
text_color_set(DW_COLOR_ERROR);
dw_printf ("\nError sending NMEA sentence. err=%d\n\n", err);
//close (nmea_port_fd);
//nmea_port_fd = MYFDERROR;
}
#endif
} /* nmea_send_sentence */
/*-------------------------------------------------------------------
*
* Name: nmea_listen_thread
*
* Purpose: Wait for messages from GPS receiver.
*
* Inputs: arg - File descriptor for reading.
*
* Outputs: pt_slave_fd - File descriptor for communicating with client app.
*
* Description: Process messages from the client application.
*
*--------------------------------------------------------------------*/
//TODO: should pass fd by reference so it can be zapped.
//BUG: If we close it here, that fact doesn't get back
// to the main receiving thread.
/* Return one byte (value 0 - 255) or terminate thread on error. */
static int nmea_get (MYFDTYPE fd)
{
unsigned char ch;
#if __WIN32__ /* Native Windows version. */
DWORD n;
static OVERLAPPED ov_rd;
memset (&ov_rd, 0, sizeof(ov_rd));
ov_rd.hEvent = CreateEvent (NULL, TRUE, FALSE, NULL);
/* Overlapped I/O makes reading rather complicated. */
/* See: http://msdn.microsoft.com/en-us/library/ms810467.aspx */
/* It seems that the read completes OK with a count */
/* of 0 every time we send a message to the serial port. */
n = 0; /* Number of characters read. */
while (n == 0) {
if ( ! ReadFile (fd, &ch, 1, &n, &ov_rd))
{
int err1 = GetLastError();
if (err1 == ERROR_IO_PENDING)
{
/* Wait for completion. */
if (WaitForSingleObject (ov_rd.hEvent, INFINITE) == WAIT_OBJECT_0)
{
if ( ! GetOverlappedResult (fd, &ov_rd, &n, 1))
{
int err3 = GetLastError();
text_color_set(DW_COLOR_ERROR);
dw_printf ("\nKISS GetOverlappedResult error %d.\n\n", err3);
}
else
{
/* Success! n should be 1 */
}
}
}
else
{
text_color_set(DW_COLOR_ERROR);
dw_printf ("\nKISS ReadFile error %d. Closing connection.\n\n", err1);
//CloseHandle (fd);
//fd = MYFDERROR;
//pthread_exit (NULL);
}
}
} /* end while n==0 */
CloseHandle(ov_rd.hEvent);
if (n != 1) {
text_color_set(DW_COLOR_ERROR);
dw_printf ("\nNMEA failed to get one byte. n=%d.\n\n", (int)n);
#if DEBUG9
fprintf (log_fp, "n=%d\n", n);
#endif
}
#else /* Linux version */
int n;
n = read(fd, &ch, (size_t)1);
if (n != 1) {
//text_color_set(DW_COLOR_ERROR);
//dw_printf ("\nError receiving kiss message from client application. Closing connection %d.\n\n", fd);
close (fd);
fd = MYFDERROR;
pthread_exit (NULL);
}
#endif
#if DEBUGx
text_color_set(DW_COLOR_DEBUG);
dw_printf ("nmea_get(%d) returns 0x%02x\n", fd, ch);
#endif
return (ch);
}
// Maximum length of message from GPS receiver.
// 82 according to some people. Larger to be safe.
#define NMEA_MAX_LEN 120
static char gps_msg[NMEA_MAX_LEN];
int gps_msg_len = 0;
#if __WIN32__
static unsigned __stdcall nmea_listen_thread (void *arg)
#else
static void * nmea_listen_thread (void *arg)
#endif
{
MYFDTYPE fd = (MYFDTYPE)(long)arg;
#if DEBUG
text_color_set(DW_COLOR_DEBUG);
dw_printf ("nmea_listen_thread ( %d )\n", fd);
#endif
while (1) {
unsigned char ch;
ch = nmea_get(fd);
if (ch == '$') {
// Start of new sentence.
gps_msg_len = 0;
gps_msg[gps_msg_len++] = ch;
gps_msg[gps_msg_len] = '\0';
}
else if (ch == '\r' || ch == '\n') {
if (gps_msg_len >= 6 && gps_msg[0] == '$') {
nmea_parse_gps (gps_msg);
text_color_set(DW_COLOR_REC);
dw_printf ("%s\n", gps_msg);
}
gps_msg_len = 0;
gps_msg[gps_msg_len] = '\0';
}
else {
if (gps_msg_len < NMEA_MAX_LEN-1) {
gps_msg[gps_msg_len++] = ch;
gps_msg[gps_msg_len] = '\0';
}
}
} /* while (1) */
return (NULL); /* Unreachable but avoids compiler warning. */
}
/*-------------------------------------------------------------------
*
* Name: ...
*
* Purpose: ...
*
* Inputs: ...
*
* Outputs: ...
*
* Description: ...
*
*--------------------------------------------------------------------*/
static void remove_checksum (char *sent)
{
char *p;
char *next;
unsigned char cs;
// Do we have valid checksum?
cs = 0;
for (p = sent+1; *p != '*' && *p != '\0'; p++) {
cs ^= *p;
}
p = strchr (sent, '*');
if (p == NULL) {
text_color_set (DW_COLOR_INFO);
dw_printf("Missing GPS checksum.\n");
return;
}
if (cs != strtoul(p+1, NULL, 16)) {
text_color_set (DW_COLOR_ERROR);
dw_printf("GPS checksum error. Expected %02x but found %s.\n", cs, p+1);
return;
}
*p = '\0'; // Remove the checksum.
}
static void nmea_parse_gps (char *sentence)
{
char stemp[NMEA_MAX_LEN];
char *ptype;
char *next;
double g_lat, g_lon;
float g_speed, g_course;
static float g_alt = G_UNKNOWN;
int fix; /* 0=none, 2=2D, 3=3D */
strcpy (stemp, sentence);
// TODO: process only if good.
remove_checksum (stemp);
next = stemp;
ptype = strsep(&next, ",");
// $GPRMC has everything we care about except altitude.
//
// Examples: $GPRMC,212404.000,V,4237.1505,N,07120.8602,W,,,150614,,*0B
// $GPRMC,000029.020,V,,,,,,,080810,,,N*45
// $GPRMC,003413.710,A,4237.1240,N,07120.8333,W,5.07,291.42,160614,,,A*7F
if (strcmp(ptype, "$GPRMC") == 0)
{
char *ptime; /* Time, hhmmss[.sss] */
char *pstatus; /* Status, A=Active (valid position), V=Void */
char *plat; /* Latitude */
char *pns; /* North/South */
char *plon; /* Longitude */
char *pew; /* East/West */
char *pknots; /* Speed over ground, knots. */
char *pcourse; /* True course, degrees. */
char *pdate; /* Date, ddmmyy */
/* Magnetic variation */
/* In version 3.00, mode is added: A D E N (see below) */
/* Checksum */
ptime = strsep(&next, ",");
pstatus = strsep(&next, ",");
plat = strsep(&next, ",");
pns = strsep(&next, ",");
plon = strsep(&next, ",");
pew = strsep(&next, ",");
pknots = strsep(&next, ",");
pcourse = strsep(&next, ",");
pdate = strsep(&next, ",");
g_lat = G_UNKNOWN;
g_lon = G_UNKNOWN;
g_speed = G_UNKNOWN;
g_course = G_UNKNOWN;
if (plat != NULL && strlen(plat) > 0) {
g_lat = latitude_from_nmea(plat, pns);
}
if (plon != NULL && strlen(plon) > 0) {
g_lon = longitude_from_nmea(plon, pew);
}
if (pknots != NULL && strlen(pknots) > 0) {
g_speed = atof(pknots);
}
if (pcourse != NULL && strlen(pcourse) > 0) {
g_course = atof(pcourse);
}
if (*pstatus == 'A') {
if (g_alt != G_UNKNOWN) {
fix = 3;
}
else {
fix = 2;
}
}
else {
fix = 0;
}
text_color_set (DW_COLOR_INFO);
dw_printf("%d %.6f %.6f %.1f %.0f %.1f\n", fix, g_lat, g_lon, g_speed, g_course, g_alt);
}
// $GPGGA has altitude.
//
// Examples: $GPGGA,212407.000,4237.1505,N,07120.8602,W,0,00,,,M,,M,,*58
// $GPGGA,000409.392,,,,,0,00,,,M,0.0,M,,0000*53
// $GPGGA,003518.710,4237.1250,N,07120.8327,W,1,03,5.9,33.5,M,-33.5,M,,0000*5B
else if (strcmp(ptype, "$GPGGA") == 0)
{
char *ptime; /* Time, hhmmss[.sss] */
char *plat; /* Latitude */
char *pns; /* North/South */
char *plon; /* Longitude */
char *pew; /* East/West */
char *pfix; /* 0=invalid, 1=GPS fix, 2=DGPS fix */
char *pnum_sat; /* Number of satellites */
char *phdop; /* Horiz. Dilution fo Precision */
char *paltitude; /* Altitude, above mean sea level */
char *palt_u; /* Units for Altitude, typically M for meters. */
char *pheight; /* Height above ellipsoid */
char *pheight_u; /* Units for height, typically M for meters. */
char *psince; /* Time since last DGPS update. */
char *pdsta; /* DGPS reference station id. */
ptime = strsep(&next, ",");
plat = strsep(&next, ",");
pns = strsep(&next, ",");
plon = strsep(&next, ",");
pew = strsep(&next, ",");
pfix = strsep(&next, ",");
pnum_sat = strsep(&next, ",");
phdop = strsep(&next, ",");
paltitude = strsep(&next, ",");
palt_u = strsep(&next, ",");
pheight = strsep(&next, ",");
pheight_u = strsep(&next, ",");
psince = strsep(&next, ",");
pdsta = strsep(&next, ",");
g_alt = G_UNKNOWN;
if (paltitude != NULL && strlen(paltitude) > 0) {
g_alt = atof(paltitude);
}
}
} /* end nmea_parse_gps */
/* end nmea.c */
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