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/* gps.h -- interface of the libgps library */
#ifndef gps_h
# define gps_h 1
#ifdef __cplusplus
extern "C" {
#endif
#include <sys/types.h>
#include <time.h>
#define MAXCHANNELS 12 /* maximum GPS channels (*not* satellites!) */
struct life_t {
/* lifetime structure to be associated with some piece of data */
time_t last_refresh;
int changed;
};
#define INIT(stamp, now) stamp.last_refresh=now
#define REFRESH(stamp) stamp.last_refresh = time(NULL)
#define SEEN(stamp) stamp.last_refresh
struct gps_data_t {
int online; /* 1 if GPS is on line, 0 if not.
*
* Note: gpsd clears this flag when sentences
* fail to show up within the GPS's normal
* send cycle time. If the host-to-GPS
* link is lossy enough to drop entire
* sentences, this flag will be
* prone to false negatives.
*/
struct life_t online_stamp;
char utc[28]; /* UTC date/time as "yyy-mm-ddThh:mm:ss.sssZ".
*
* Updated on every valid fix (GGA, GLL or
* GPRMC). The hhmmss.ss part is reliable to
* within one GPS send cycle time (normally one
* second). Altitude could be one send cycle
* older than the timestamp if the last
* sentence was GPRMC.
*
* Within one GPS send cycle after midnight,
* if the last sentence was GGA or GLL and not
* GPRMC, the date could be off by one.
*
* The century part of the year is spliced in
* from host-machine time.
*/
/*
* Position/velocity fields are only valid when the last_refresh
* field of the associated timestamp is nonzero, in which case it
* tells when the data was collected.
*/
double latitude; /* Latitude in degrees */
double longitude; /* Longitude in degrees */
struct life_t latlon_stamp;
double altitude; /* Altitude in meters */
struct life_t altitude_stamp;
/* velocity */
double speed; /* Speed over ground, knots */
struct life_t speed_stamp;
double track; /* Course made good (relative to true north) */
struct life_t track_stamp;
/* status of fix */
int status; /* Do we have a fix? */
#define STATUS_NO_FIX 0 /* no */
#define STATUS_FIX 1 /* yes, without DGPS */
#define STATUS_DGPS_FIX 2 /* yes, with DGPS */
struct life_t status_stamp;
int mode; /* Mode of fix */
#define MODE_NOT_SEEN 0 /* GSA not seen yet */
#define MODE_NO_FIX 1 /* none */
#define MODE_2D 2 /* good for latitude/longitude */
#define MODE_3D 3 /* good for altitude too */
struct life_t mode_stamp;
/* precision of fix */
int satellites_used; /* Number of satellites used in solution */
int used[MAXCHANNELS]; /* Used in last fix? */
double pdop, hdop, vdop; /* Dilution of precision */
struct life_t fix_quality_stamp;
/* satellite status */
int satellites; /* # of satellites in view */
int PRN[MAXCHANNELS]; /* PRNs of satellite */
int elevation[MAXCHANNELS]; /* elevation of satellite */
int azimuth[MAXCHANNELS]; /* azimuth */
int ss[MAXCHANNELS]; /* signal strength */
int part, await; /* for tracking GSV parts */
struct life_t satellite_stamp;
/* these members are private */
int gps_fd; /* socket or file descriptor to GPS */
void (*raw_hook)(char *buf);/* Raw-mode hook for GPS data. */
};
struct gps_data_t *gps_open(const char *host, const char *port);
int gps_close(struct gps_data_t *);
int gps_query(struct gps_data_t *gpsdata, const char *requests);
int gps_poll(struct gps_data_t *gpsdata);
void gps_set_raw_hook(struct gps_data_t *gpsdata, void (*hook)(char *buf));
/* some multipliers for interpreting GPS output */
#define METERS_TO_FEET 3.2808399 /* Imperial (U.S./British) feet */
#define METERS_TO_MILES 0.00062137119 /* International miles */
#define KNOTS_TO_MPH 1.1507794 /* International miles and knots */
#define KNOTS_TO_KPH 1.852 /* International knots */
#define PI 3.14159265358979323846 /* for radians-to-degrees and vv. */
/* gps_open() error return values */
#define NL_NOSERVICE -1 /* can't get service entry */
#define NL_NOHOST -2 /* can't get host entry */
#define NL_NOPROTO -3 /* can't get protocol entry */
#define NL_NOSOCK -4 /* can't create socket */
#define NL_NOSOCKOPT -5 /* error SETSOCKOPT SO_REUSEADDR */
#define NL_NOCONNECT -6 /* can't connect to host */
#define DEFAULT_GPSD_PORT "2947" /* IANA assignment */
#ifdef __cplusplus
} /* End of the 'extern "C"' block */
#endif
#endif /* gps_h */
/* gps.h ends here */
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