zodiac.c

来自「gpsd, a popular GPS daemon.」· C语言 代码 · 共 457 行 · 第 1/2 页

/* $Id: zodiac.c 4661 2008-01-19 22:54:23Z garyemiller $ */
/*
 * Handle the Rockwell binary packet format supported by the old Zodiac chipset
 */
#include <sys/types.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <math.h>
#include "gpsd_config.h"
#include "gpsd.h"

#define LITTLE_ENDIAN_PROTOCOL
#include "bits.h"

#ifdef ZODIAC_ENABLE
struct header {
    unsigned short sync;
    unsigned short id;
    unsigned short ndata;
    unsigned short flags;
    unsigned short csum;
};

static unsigned short zodiac_checksum(unsigned short *w, int n)
{
    unsigned short csum = 0;

    while (n-- > 0)
	csum += *(w++);
    return -csum;
}

/* zodiac_spew - Takes a message type, an array of data words, and a length
   for the array, and prepends a 5 word header (including checksum).
   The data words are expected to be checksummed */
#if defined (WORDS_BIGENDIAN)
/* data is assumed to contain len/2 unsigned short words
 * we change the endianness to little, when needed.
 */
static int end_write(int fd, void *d, int len)
{
    char buf[BUFSIZ];
    char *p = buf;
    char *data = (char *)d;
    size_t n = (size_t)len;

    while (n>0) {
	*p++ = *(data+1); *p++ = *data;
	data += 2; n -= 2;
    }
    return write(fd, buf, len);
}
#else
#define end_write write
#endif

static void zodiac_spew(struct gps_device_t *session, int type, unsigned short *dat, int dlen)
{
    struct header h;
    int i;
    char buf[BUFSIZ];

    h.sync = 0x81ff;
    h.id = (unsigned short)type;
    h.ndata = (unsigned short)(dlen - 1);
    h.flags = 0;
    h.csum = zodiac_checksum((unsigned short *) &h, 4);

    if (session->gpsdata.gps_fd != -1) {
#ifdef ALLOW_RECONFIGURE
	(void)end_write(session->gpsdata.gps_fd, &h, sizeof(h));
	(void)end_write(session->gpsdata.gps_fd, dat, sizeof(unsigned short) * dlen);
#endif /* ALLOW_RECONFIGURE */
    }

    (void)snprintf(buf, sizeof(buf),
		   "%04x %04x %04x %04x %04x",
		   h.sync,h.id,h.ndata,h.flags,h.csum);
    for (i = 0; i < dlen; i++)
	(void)snprintf(buf+strlen(buf), sizeof(buf)-strlen(buf),
		       " %04x", dat[i]);

    gpsd_report(LOG_RAW, "Sent Zodiac packet: %s\n",buf);
}

static bool zodiac_speed_switch(struct gps_device_t *session, speed_t speed)
{
    unsigned short data[15];

    if (session->driver.zodiac.sn++ > 32767)
	session->driver.zodiac.sn = 0;
      
    memset(data, 0, sizeof(data));
    /* data is the part of the message starting at word 6 */
    data[0] = session->driver.zodiac.sn;	/* sequence number */
    data[1] = 1;			/* port 1 data valid */
    data[2] = 1;			/* port 1 character width (8 bits) */
    data[3] = 0;			/* port 1 stop bits (1 stopbit) */
    data[4] = 0;			/* port 1 parity (none) */
    data[5] = (unsigned short)(round(log((double)speed/300)/M_LN2)+1); /* port 1 speed */
    data[14] = zodiac_checksum(data, 14);

    zodiac_spew(session, 1330, data, 15);
#ifdef ALLOW_RECONFIGURE
    return true; /* it would be nice to error-check this */
#else
    return false;
#endif /* ALLOW_RECONFIGURE */

}

static void send_rtcm(struct gps_device_t *session, 
		      char *rtcmbuf, size_t rtcmbytes)
{
    unsigned short data[34];
    int n = 1 + (int)(rtcmbytes/2 + rtcmbytes%2);

    if (session->driver.zodiac.sn++ > 32767)
	session->driver.zodiac.sn = 0;

    memset(data, 0, sizeof(data));
    data[0] = session->driver.zodiac.sn;		/* sequence number */
    memcpy(&data[1], rtcmbuf, rtcmbytes);
    data[n] = zodiac_checksum(data, n);

    zodiac_spew(session, 1351, data, n+1);
}

static ssize_t zodiac_send_rtcm(struct gps_device_t *session,
			char *rtcmbuf, size_t rtcmbytes)
{
    size_t len;

    while (rtcmbytes > 0) {
	len = (size_t)(rtcmbytes>64?64:rtcmbytes);
	send_rtcm(session, rtcmbuf, len);
	rtcmbytes -= len;
	rtcmbuf += len;
    }
    return 1;
}

static gps_mask_t handle1000(struct gps_device_t *session)
{
    double subseconds;
    struct tm unpacked_date;
    /* ticks                      = getlong(6); */
    /* sequence                   = getword(8); */
    /* measurement_sequence       = getword(9); */
    /*@ -boolops -predboolothers @*/
    session->gpsdata.status       = (getword(10) & 0x1c) ? 0 : 1;
    if (session->gpsdata.status != 0)
	session->gpsdata.fix.mode = (getword(10) & 1) ? MODE_2D : MODE_3D;
    else
	session->gpsdata.fix.mode = MODE_NO_FIX;
    /*@ +boolops -predboolothers @*/

    /* solution_type                 = getword(11); */
    session->gpsdata.satellites_used = (int)getword(12);
    /* polar_navigation              = getword(13); */
    /* gps_week                      = getword(14); */
    /* gps_seconds                   = getlong(15); */
    /* gps_nanoseconds               = getlong(17); */
    unpacked_date.tm_mday = (int)getword(19);
    unpacked_date.tm_mon = (int)getword(20) - 1;
    unpacked_date.tm_year = (int)getword(21) - 1900;
    unpacked_date.tm_hour = (int)getword(22);
    unpacked_date.tm_min = (int)getword(23);
    unpacked_date.tm_sec = (int)getword(24);
    subseconds = (int)getlong(25) / 1e9;
    /*@ -compdef */
    session->gpsdata.fix.time = session->gpsdata.sentence_time =
	(double)mkgmtime(&unpacked_date) + subseconds;
    /*@ +compdef */
#ifdef NTPSHM_ENABLE
    /* Removing/changing the magic number below is likely to disturb
     * the handling of the 1pps signal from the gps device. The regression
     * tests and simple gps applications do not detect this. A live test
     * with the 1pps signal active is required. */
    if (session->context->enable_ntpshm && session->gpsdata.fix.mode > MODE_NO_FIX)
	(void)ntpshm_put(session, session->gpsdata.fix.time + 1.1);
#endif
    /*@ -type @*/
    session->gpsdata.fix.latitude  = ((long)getlong(27)) * RAD_2_DEG * 1e-8;
    session->gpsdata.fix.longitude = ((long)getlong(29)) * RAD_2_DEG * 1e-8;
    /*
     * The Rockwell Jupiter TU30-D140 reports altitude as uncorrected height
     * above WGS84 geoid.  The Zodiac binary protocol manual does not 
     * specify whether word 31 is geodetic or WGS 84. 
     */
    session->gpsdata.fix.altitude  = ((long)getlong(31)) * 1e-2;
    /*@ +type @*/
    session->gpsdata.separation    = ((short)getword(33)) * 1e-2;
    session->gpsdata.fix.altitude -= session->gpsdata.separation;
    session->gpsdata.fix.speed     = (int)getlong(34) * 1e-2;
    session->gpsdata.fix.track     = (int)getword(36) * RAD_2_DEG * 1e-3;
    session->mag_var               = ((short)getword(37)) * RAD_2_DEG * 1e-4;
    session->gpsdata.fix.climb     = ((short)getword(38)) * 1e-2;
    /* map_datum                   = getword(39); */
    /* manual says these are 1-sigma */
    session->gpsdata.fix.eph       = (int)getlong(40) * 1e-2 * GPSD_CONFIDENCE;
    session->gpsdata.fix.epv       = (int)getlong(42) * 1e-2 * GPSD_CONFIDENCE;
    session->gpsdata.fix.ept       = (int)getlong(44) * 1e-2 * GPSD_CONFIDENCE;
    session->gpsdata.fix.eps       = (int)getword(46) * 1e-2 * GPSD_CONFIDENCE;
    /* clock_bias                  = (int)getlong(47) * 1e-2; */
    /* clock_bias_sd               = (int)getlong(49) * 1e-2; */
    /* clock_drift                 = (int)getlong(51) * 1e-2; */
    /* clock_drift_sd              = (int)getlong(53) * 1e-2; */

#if 0
    gpsd_report(LOG_INF, "date: %lf\n", session->gpsdata.fix.time);
    gpsd_report(LOG_INF, "  solution invalid:\n");
    gpsd_report(LOG_INF, "    altitude: %d\n", (getword(10) & 1) ? 1 : 0);
    gpsd_report(LOG_INF, "    no diff gps: %d\n", (getword(10) & 2) ? 1 : 0);
    gpsd_report(LOG_INF, "    not enough satellites: %d\n", (getword(10) & 4) ? 1 : 0);
    gpsd_report(LOG_INF, "    exceed max EHPE: %d\n", (getword(10) & 8) ? 1 : 0);
    gpsd_report(LOG_INF, "    exceed max EVPE: %d\n", (getword(10) & 16) ? 1 : 0);
    gpsd_report(LOG_INF, "  solution type:\n");
    gpsd_report(LOG_INF, "    propagated: %d\n", (getword(11) & 1) ? 1 : 0);
    gpsd_report(LOG_INF, "    altitude: %d\n", (getword(11) & 2) ? 1 : 0);
    gpsd_report(LOG_INF, "    differential: %d\n", (getword(11) & 4) ? 1 : 0);
    gpsd_report(LOG_INF, "Number of measurements in solution: %d\n", getword(12));
    gpsd_report(LOG_INF, "Lat: %f\n", getlong(27) * RAD_2_DEG * 1e-8);
    gpsd_report(LOG_INF, "Lon: %f\n", getlong(29) * RAD_2_DEG * 1e-8);
    gpsd_report(LOG_INF, "Alt: %f\n", (double) getlong(31) * 1e-2);
    gpsd_report(LOG_INF, "Speed: %f\n", (double) getlong(34) * 1e-2 * MPS_TO_KNOTS);
    gpsd_report(LOG_INF, "Map datum: %d\n", getword(39));