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/*
* This is the gpsd driver for Skytraq GPSes operating in binary mode.
*
* This file is Copyright (c) 2016 by the GPSD project
* BSD terms apply: see the file COPYING in the distribution root for details.
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <strings.h>
#include <math.h>
#include <ctype.h>
#include <unistd.h>
#include "gpsd.h"
#include "bits.h"
#include "strfuncs.h"
#if defined(SKYTRAQ_ENABLE)
#define HI(n) ((n) >> 8)
#define LO(n) ((n) & 0xff)
/*
* No ACK/NAK? Just rety after 6 seconds
*/
#define SKY_RETRY_TIME 6
#define SKY_CHANNELS 48 /* max channels allowed in format */
static gps_mask_t sky_parse(struct gps_device_t *, unsigned char *, size_t);
static gps_mask_t sky_msg_svinfo(struct gps_device_t *, unsigned char *,
size_t);
/*
* decode MID 0xDE, SV and channel status
*
* max payload: 3 + (Num_sats * 10) = 483 bytes
*/
static gps_mask_t sky_msg_svinfo(struct gps_device_t *session,
unsigned char *buf, size_t len)
{
int st, i, j, nsv;
unsigned int iod; /* Issue of data 0 - 255 */
int nsvs; /* number of SVs in this packet */
iod = (unsigned int)buf[1];
nsvs = (int)buf[2];
/* too many sats? */
if ( SKY_CHANNELS < nsvs )
return 0;
gpsd_zero_satellites(&session->gpsdata);
for (i = st = nsv = 0; i < nsvs; i++) {
int off = 3 + (10 * i); /* offset into buffer of start of this sat */
bool good; /* do we have a good record ? */
unsigned short sv_stat;
unsigned short chan_stat;
unsigned short ura;
session->gpsdata.skyview[st].PRN = (short)getub(buf, off + 1);
sv_stat = (unsigned short)getub(buf, off + 2);
ura = (unsigned short)getub(buf, off + 3);
session->gpsdata.skyview[st].ss = (float)getub(buf, off + 4);
session->gpsdata.skyview[st].elevation =
(short)getles16(buf, off + 5);
session->gpsdata.skyview[st].azimuth =
(short)getles16(buf, off + 7);
chan_stat = (unsigned short)getub(buf, off + 9);
session->gpsdata.skyview[st].used = (bool)(chan_stat & 0x30);
good = session->gpsdata.skyview[st].PRN != 0 &&
session->gpsdata.skyview[st].azimuth != 0 &&
session->gpsdata.skyview[st].elevation != 0;
// #ifndef UNUSED
gpsd_log(&session->context->errout, 1, /* PROG, */
"Skytraq: PRN=%2d El=%d Az=%d ss=%3.2f stat=%02x,%02x ura=%d %c\n",
session->gpsdata.skyview[st].PRN,
session->gpsdata.skyview[st].elevation,
session->gpsdata.skyview[st].azimuth,
session->gpsdata.skyview[st].ss,
chan_stat, sv_stat, ura,
good ? '*' : ' ');
// #endif /* UNUSED */
if ( good ) {
st += 1;
if (session->gpsdata.skyview[st].used)
nsv++;
}
}
session->gpsdata.satellites_visible = st;
session->gpsdata.satellites_used = nsv;
gpsd_log(&session->context->errout, LOG_DATA,
"Skytraq: MID 0xDE: nsvs=%d visible=%d iod=%d\n", nsvs,
session->gpsdata.satellites_visible, iod);
return SATELLITE_SET;
}
static gps_mask_t sky_parse(struct gps_device_t * session, unsigned char *buf,
size_t len)
{
if (len == 0)
return 0;
buf += 4;
len -= 8;
// session->driver.sirf.lastid = buf[0];
/* could change if the set of messages we enable does */
session->cycle_end_reliable = true;
switch (buf[0]) {
case 0xDE:
return sky_msg_svinfo(session, buf, len);
default:
gpsd_log(&session->context->errout, LOG_PROG,
"Skytraq: Unknown packet id %d length %zd\n",
buf[0], len);
return 0;
}
return 0;
}
static gps_mask_t skybin_parse_input(struct gps_device_t *session)
{
if (session->lexer.type == SKY_PACKET) {
return sky_parse(session, session->lexer.outbuffer,
session->lexer.outbuflen);
#ifdef NMEA0183_ENABLE
} else if (session->lexer.type == NMEA_PACKET) {
return nmea_parse((char *)session->lexer.outbuffer, session);
#endif /* NMEA0183_ENABLE */
} else
return 0;
}
/* this is everything we export */
/* *INDENT-OFF* */
const struct gps_type_t driver_skytraq =
{
.type_name = "Skytraq", /* full name of type */
.packet_type = SKY_PACKET, /* associated lexer packet type */
.flags = DRIVER_STICKY, /* remember this */
.trigger = NULL, /* no trigger */
.channels = SKY_CHANNELS, /* consumer-grade GPS */
.probe_detect = NULL, /* no probe */
.get_packet = generic_get, /* be prepared for Skytraq or NMEA */
.parse_packet = skybin_parse_input,/* parse message packets */
.rtcm_writer = gpsd_write, /* send RTCM data straight */
.init_query = NULL, /* non-perturbing initial qury */
.event_hook = NULL, /* lifetime event handler */
};
/* *INDENT-ON* */
#endif /* defined( SKYTRAQ_ENABLE) && defined(BINARY_ENABLE) */
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