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/* $Id$ */
#ifndef _GPSD_GPS_H_
#define _GPSD_GPS_H_
/* gps.h -- interface of the libgps library */
#ifdef __cplusplus
extern "C" {
#endif
#include <sys/types.h>
#include <sys/time.h>
#include <stdbool.h>
#include <inttypes.h> /* stdint.h would be smaller but not all have it */
#include <limits.h>
#include <time.h>
#include <signal.h>
#ifndef S_SPLINT_S
#include <pthread.h> /* pacifies OpenBSD's compiler */
#endif
#define MAXTAGLEN 8 /* maximum length of sentence tag name */
#define MAXCHANNELS 20 /* maximum GPS channels (*not* satellites!) */
#define SIRF_CHANNELS 12 /* max channels allowed in SiRF format */
#define GPS_PRNMAX 32 /* above this number are SBAS satellites */
/*
* The structure describing an uncertainty volume in kinematic space.
* This is what GPSes are meant to produce; all the other info is
* technical impedimenta.
*
* All double values use NAN to indicate data not available.
*
* Usually all the information in this structure was considered valid
* by the GPS at the time of update. This will be so if you are using
* a GPS chipset that speaks SiRF binary, Garmin binary, or Zodiac binary.
* This covers over 80% of GPS products in early 2005.
*
* If you are using a chipset that speaks NMEA, this structure is updated
* in bits by GPRMC (lat/lon, track, speed), GPGGA (alt, climb), GPGLL
* (lat/lon), and GPGSA (eph, epv). Most NMEA GPSes take a single fix
* at the beginning of a 1-second cycle and report the same timestamp in
* GPRMC, GPGGA, and GPGLL; for these, all info is guaranteed correctly
* synced to the time member, but you'll get different stages of the same
* update depending on where in the cycle you poll. A very few GPSes,
* like the Garmin 48, take a new fix before more than one of of
* GPRMC/GPGGA/GPGLL during a single cycle; thus, they may have different
* timestamps and some data in this structure can be up to 1 cycle (usually
* 1 second) older than the fix time.
*
* Error estimates are at 95% confidence.
*/
struct gps_fix_t {
double time; /* Time of update, seconds since Unix epoch */
int mode; /* Mode of fix */
#define MODE_NOT_SEEN 0 /* mode update not seen yet */
#define MODE_NO_FIX 1 /* none */
#define MODE_2D 2 /* good for latitude/longitude */
#define MODE_3D 3 /* good for altitude/climb too */
double ept; /* Expected time uncertainty */
double latitude; /* Latitude in degrees (valid if mode >= 2) */
double longitude; /* Longitude in degrees (valid if mode >= 2) */
double eph; /* Horizontal position uncertainty, meters */
double altitude; /* Altitude in meters (valid if mode == 3) */
double epv; /* Vertical position uncertainty, meters */
double track; /* Course made good (relative to true north) */
double epd; /* Track uncertainty, degrees */
double speed; /* Speed over ground, meters/sec */
double eps; /* Speed uncertainty, meters/sec */
double climb; /* Vertical speed, meters/sec */
double epc; /* Vertical speed uncertainty */
};
/*
* From the RCTM104 2.x standard:
*
* "The 30 bit words (as opposed to 32 bit words) coupled with a 50 Hz
* transmission rate provides a convenient timing capability where the
* times of word boundaries are a rational multiple of 0.6 seconds."
*
* "Each frame is N+2 words long, where N is the number of message data
* words. For example, a filler message (type 6 or 34) with no message
* data will have N=0, and will consist only of two header words. The
* maximum number of data words allowed by the format is 31, so that
* the longest possible message will have a total of 33 words."
*/
#define RTCM2_WORDS_MAX 33
#define MAXCORRECTIONS 18 /* max correction count in type 1 or 9 */
#define MAXSTATIONS 10 /* maximum stations in almanac, type 5 */
/* RTCM104 doesn't specify this, so give it the largest reasonable value */
#define MAXHEALTH (RTCM2_WORDS_MAX-2)
#ifndef S_SPLINT_S
/*
* A nominally 30-bit word (24 bits of data, 6 bits of parity)
* used both in the GPS downlink protocol described in IS-GPS-200
* and in the format for DGPS corrections used in RTCM-104v2.
*/
typedef /*@unsignedintegraltype@*/ uint32_t isgps30bits_t;
#endif /* S_SPLINT_S */
typedef enum {gps, glonass, galileo, unknown} navsystem;
struct rtcm2_t {
/* header contents */
unsigned type; /* RTCM message type */
unsigned length; /* length (words) */
double zcount; /* time within hour: GPS time, no leap secs */
unsigned refstaid; /* reference station ID */
unsigned seqnum; /* message sequence number (modulo 8) */
unsigned stathlth; /* station health */
/* message data in decoded form */
union {
struct {
unsigned int nentries;
struct rangesat_t { /* data from messages 1 & 9 */
unsigned ident; /* satellite ID */
unsigned udre; /* user diff. range error */
unsigned issuedata; /* issue of data */
double rangerr; /* range error */
double rangerate; /* range error rate */
} sat[MAXCORRECTIONS];
} ranges;
struct { /* data for type 3 messages */
bool valid; /* is message well-formed? */
double x, y, z;
} ecef;
struct { /* data from type 4 messages */
bool valid; /* is message well-formed? */
navsystem system;
enum {local, global, invalid} sense;
char datum[6];
double dx, dy, dz;
} reference;
struct { /* data from type 5 messages */
unsigned int nentries;
struct consat_t {
unsigned ident; /* satellite ID */
bool iodl; /* issue of data */
unsigned int health; /* is satellite healthy? */
#define HEALTH_NORMAL (0) /* Radiobeacon operation normal */
#define HEALTH_UNMONITORED (1) /* No integrity monitor operating */
#define HEALTH_NOINFO (2) /* No information available */
#define HEALTH_DONOTUSE (3) /* Do not use this radiobeacon */
int snr; /* signal-to-noise ratio, dB */
#define SNR_BAD -1 /* not reported */
unsigned int health_en; /* health enabled */
bool new_data; /* new data? */
bool los_warning; /* line-of-sight warning */
unsigned int tou; /* time to unhealth, seconds */
} sat[MAXHEALTH];
} conhealth;
struct { /* data from type 7 messages */
unsigned int nentries;
struct station_t {
double latitude, longitude; /* location */
unsigned int range; /* range in km */
double frequency; /* broadcast freq */
unsigned int health; /* station health */
unsigned int station_id; /* of the transmitter */
unsigned int bitrate; /* of station transmissions */
} station[MAXSTATIONS];
} almanac;
/* data from type 16 messages */
char message[(RTCM2_WORDS_MAX-2) * sizeof(isgps30bits_t)];
/* data from messages of unknown type */
isgps30bits_t words[RTCM2_WORDS_MAX-2];
} msg_data;
};
/* RTCM3 report structures begin here */
#define RTCM3_MAX_SATELLITES 64
#define RTCM3_MAX_DESCRIPTOR 31
#define RTCM3_MAX_ANNOUNCEMENTS 32
struct rtcm3_rtk_hdr { /* header data from 1001, 1002, 1003, 1004 */
/* Used for both GPS and GLONASS, but their timebases differ */
unsigned int msgnum; /* Message number */
unsigned int station_id; /* Reference Station ID */
time_t tow; /* GPS Epoch Time (TOW) in ms,
or GLONASS Epoch Time in ms */
bool sync; /* Synchronous GNSS Message Flag */
ushort satcount; /* # Satellite Signals Processed */
bool smoothing; /* Divergence-free Smoothing Indicator */
ushort interval; /* Smoothing Interval */
};
struct rtcm3_basic_rtk {
unsigned char indicator; /* Indicator */
unsigned char channel; /* Satellite Frequency Channel Number
(GLONASS only) */
double pseudorange; /* Pseudorange */
double rangediff; /* PhaseRange – Pseudorange in meters */
unsigned char locktime; /* Lock time Indicator */
};
struct rtcm3_extended_rtk {
unsigned char indicator; /* Indicator */
unsigned char channel; /* Satellite Frequency Channel Number
(GLONASS only) */
double pseudorange; /* Pseudorange */
double rangediff; /* PhaseRange – L1 Pseudorange */
unsigned char locktime; /* Lock time Indicator */
unsigned char ambiguity; /* Integer Pseudorange
Modulus Ambiguity */
double CNR; /* Carrier-to-Noise Ratio */
};
struct rtcm3_network_rtk_header {
unsigned int msgnum; /* Message number */
unsigned int network_id; /* Network ID */
unsigned int subnetwork_id; /* Subnetwork ID */
time_t time; /* GPS Epoch Time (TOW) in ms */
bool multimesg; /* GPS Multiple Message Indicator */
unsigned master_id; /* Master Reference Station ID */
unsigned aux_id; /* Auxilary Reference Station ID */
unsigned char satcount; /* count of GPS satellites */
};
struct rtcm3_correction_diff {
unsigned char ident; /* satellite ID */
enum {reserved, correct, widelane, uncertain} ambiguity;
unsigned char nonsync;
double geometric_diff; /* Geometric Carrier Phase
Correction Difference (1016, 1017) */
unsigned char iode; /* GPS IODE (1016, 1017) */
double ionospheric_diff; /* Ionospheric Carrier Phase
Correction Difference (1015, 1017) */
};
struct rtcm3_t {
/* header contents */
unsigned type; /* RTCM 3.x message type */
unsigned length; /* payload length, inclusive of checksum */
union {
/* 1001-1013 were present in the 3.0 version */
struct {
struct rtcm3_rtk_hdr header;
struct {
unsigned ident; /* Satellite ID */
struct rtcm3_basic_rtk L1;
} rtk_data[RTCM3_MAX_SATELLITES];
} rtcm3_1001;
struct {
struct rtcm3_rtk_hdr header;
struct {
unsigned ident; /* Satellite ID */
struct rtcm3_extended_rtk L1;
} rtk_data[RTCM3_MAX_SATELLITES];
} rtcm3_1002;
struct {
struct rtcm3_rtk_hdr header;
struct {
unsigned ident; /* Satellite ID */
struct rtcm3_basic_rtk L1;
struct rtcm3_basic_rtk L2;
} rtk_data[RTCM3_MAX_SATELLITES];
} rtcm3_1003;
struct {
struct rtcm3_rtk_hdr header;
struct {
unsigned ident; /* Satellite ID */
struct rtcm3_extended_rtk L1;
struct rtcm3_extended_rtk L2;
} rtk_data[RTCM3_MAX_SATELLITES];
} rtcm3_1004;
struct {
unsigned int station_id; /* Reference Station ID */
navsystem system; /* Which system is it? */
bool reference_station; /* Reference-station indicator */
bool single_receiver; /* Single Receiver Oscillator */
double ecef_x, ecef_y, ecef_z; /* ECEF antenna location */
} rtcm3_1005;
struct {
unsigned int station_id; /* Reference Station ID */
navsystem system; /* Which system is it? */
bool reference_station; /* Reference-station indicator */
bool single_receiver; /* Single Receiver Oscillator */
double ecef_x, ecef_y, ecef_z; /* ECEF antenna location */
double height; /* Antenna height */
} rtcm3_1006;
struct {
unsigned int station_id; /* Reference Station ID */
char descriptor[RTCM3_MAX_DESCRIPTOR+1]; /* Description string */
unsigned char setup_id;
} rtcm3_1007;
struct {
unsigned int station_id; /* Reference Station ID */
char descriptor[RTCM3_MAX_DESCRIPTOR+1]; /* Description string */
unsigned char setup_id;
char serial[RTCM3_MAX_DESCRIPTOR+1]; /* Serial # string */
} rtcm3_1008;
struct {
struct rtcm3_rtk_hdr header;
struct {
unsigned ident; /* Satellite ID */
struct rtcm3_basic_rtk L1;
} rtk_data[RTCM3_MAX_SATELLITES];
} rtcm3_1009;
struct {
struct rtcm3_rtk_hdr header;
struct {
unsigned ident; /* Satellite ID */
struct rtcm3_extended_rtk L1;
} rtk_data[RTCM3_MAX_SATELLITES];
} rtcm3_1010;
struct {
struct rtcm3_rtk_hdr header;
struct {
unsigned ident; /* Satellite ID */
struct rtcm3_extended_rtk L1;
struct rtcm3_extended_rtk L2;
} rtk_data[RTCM3_MAX_SATELLITES];
} rtcm3_1011;
struct {
struct rtcm3_rtk_hdr header;
struct {
unsigned ident; /* Satellite ID */
struct rtcm3_extended_rtk L1;
struct rtcm3_extended_rtk L2;
} rtk_data[RTCM3_MAX_SATELLITES];
} rtcm3_1012;
struct {
unsigned int msgnum; /* Message number */
unsigned int station_id; /* Reference Station ID */
unsigned short mjd; /* Modified Julian Day (MJD) Number */
unsigned int sod; /* Seconds of Day (UTC) */
unsigned char leapsecs; /* Leap Seconds, GPS-UTC */
unsigned char ncount; /* Count of announcements to follow */
struct {
unsigned short id;
bool sync;
unsigned short interval;
} announcements[RTCM3_MAX_ANNOUNCEMENTS];
} rtcm3_1013;
/* 1014-1017 were added in the 3.1 version */
struct {
unsigned int msgnum; /* Message number */
unsigned int network_id; /* Network ID */
unsigned int subnetwork_id; /* Subnetwork ID */
unsigned char stationcount; /* # auxiliary stations transmitted */
unsigned int master_id; /* Master Reference Station ID */
unsigned int aux_id; /* Auxilary Reference Station ID */
double d_lat, d_lon, d_alt; /* Aux-master location delta */
} rtcm3_1014;
struct {
struct rtcm3_network_rtk_header header;
struct rtcm3_correction_diff corrections[RTCM3_MAX_SATELLITES];
} rtcm3_1015;
struct {
struct rtcm3_network_rtk_header header;
struct rtcm3_correction_diff corrections[RTCM3_MAX_SATELLITES];
} rtcm3_1016;
struct {
struct rtcm3_network_rtk_header header;
struct rtcm3_correction_diff corrections[RTCM3_MAX_SATELLITES];
} rtcm3_1017;
struct {
unsigned int msgnum; /* Message number */
unsigned int ident; /* Satellite ID */
unsigned int week; /* GPS Week Number */
unsigned char sv_accuracy; /* GPS SV ACCURACY */
enum {reserved_code, p, ca, l2c} code;
double idot;
unsigned char iode;
/* ephemeris fields, not scaled */
unsigned int t_sub_oc;
signed int a_sub_f2;
signed int a_sub_f1;
signed int a_sub_f0;
unsigned int iodc;
signed int C_sub_rs;
signed int delta_sub_n;
signed int M_sub_0;
signed int C_sub_uc;
unsigned int e;
signed int C_sub_us;
unsigned int sqrt_sub_A;
unsigned int t_sub_oe;
signed int C_sub_ic;
signed int OMEGA_sub_0;
signed int C_sub_is;
signed int i_sub_0;
signed int C_sub_rc;
signed int argument_of_perigee;
signed int omegadot;
signed int t_sub_GD;
unsigned char sv_health;
bool p_data;
bool fit_interval;
} rtcm3_1019;
struct {
unsigned int msgnum; /* Message number */
unsigned int ident; /* Satellite ID */
unsigned short channel; /* Satellite Frequency Channel Number */
/* ephemeris fields, not scaled */
bool C_sub_n;
bool health_avAilability_indicator;
unsigned char P1;
unsigned short t_sub_k;
bool msb_of_B_sub_n;
bool P2;
bool t_sub_b;
signed int x_sub_n_t_of_t_sub_b_prime;
signed int x_sub_n_t_of_t_sub_b;
signed int x_sub_n_t_of_t_sub_b_prime_prime;
signed int y_sub_n_t_of_t_sub_b_prime;
signed int y_sub_n_t_of_t_sub_b;
signed int y_sub_n_t_of_t_sub_b_prime_prime;
signed int z_sub_n_t_of_t_sub_b_prime;
signed int z_sub_n_t_of_t_sub_b;
signed int z_sub_n_t_of_t_sub_b_prime_prime;
bool P3;
signed int gamma_sub_n_of_t_sub_b;
unsigned char MP;
bool Ml_n;
signed int tau_n_of_t_sub_b;
signed int M_delta_tau_sub_n;
unsigned int E_sub_n;
bool MP4;
unsigned char MF_sub_T;
unsigned char MN_sub_T;
unsigned char MM;
bool additioinal_data_availability;
unsigned int N_sup_A;
unsigned int tau_sub_c;
unsigned int M_N_sub_4;
signed int M_tau_sub_GPS;
bool M_l_sub_n;
} rtcm3_1020;
struct {
unsigned int msgnum; /* Message number */
unsigned int station_id; /* Reference Station ID */
unsigned short mjd; /* Modified Julian Day (MJD) Number */
unsigned int sod; /* Seconds of Day (UTC) */
unsigned char len; /* # Chars to follow */
unsigned char unicode_units;
unsigned char text[128];
} rtcm3_1029;
} rtcmtypes;
};
typedef /*@unsignedintegraltype@*/ unsigned int gps_mask_t;
struct gps_data_t {
gps_mask_t set; /* has field been set since this was last cleared? */
#define ONLINE_SET 0x00000001u
#define TIME_SET 0x00000002u
#define TIMERR_SET 0x00000004u
#define LATLON_SET 0x00000008u
#define ALTITUDE_SET 0x00000010u
#define SPEED_SET 0x00000020u
#define TRACK_SET 0x00000040u
#define CLIMB_SET 0x00000080u
#define STATUS_SET 0x00000100u
#define MODE_SET 0x00000200u
#define HDOP_SET 0x00000400u
#define VDOP_SET 0x00000800u
#define PDOP_SET 0x00001000u
#define TDOP_SET 0x00002000u
#define GDOP_SET 0x00004000u
#define DOP_SET (HDOP_SET|VDOP_SET|PDOP_SET|TDOP_SET|GDOP_SET)
#define HERR_SET 0x00008000u
#define VERR_SET 0x00010000u
#define PERR_SET 0x00020000u
#define ERR_SET (HERR_SET | VERR_SET | PERR_SET)
#define SATELLITE_SET 0x00040000u
#define PSEUDORANGE_SET 0x00080000u
#define USED_SET 0x00100000u
#define SPEEDERR_SET 0x00200000u
#define TRACKERR_SET 0x00400000u
#define CLIMBERR_SET 0x00800000u
#define DEVICE_SET 0x01000000u
#define DEVICELIST_SET 0x02000000u
#define DEVICEID_SET 0x04000000u
#define ERROR_SET 0x08000000u
#define CYCLE_START_SET 0x10000000u
#define RTCM2_SET 0x20000000u
#define RTCM3_SET 0x40000000u
#define FIX_SET (TIME_SET|MODE_SET|TIMERR_SET|LATLON_SET|HERR_SET|ALTITUDE_SET|VERR_SET|TRACK_SET|TRACKERR_SET|SPEED_SET|SPEEDERR_SET|CLIMB_SET|CLIMBERR_SET)
double online; /* NZ 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 gps_fix_t fix; /* accumulated PVT data */
double separation; /* Geoidal separation, MSL - WGS84 (Meters) */
/* GPS status -- always valid */
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 */
/* precision of fix -- valid if satellites_used > 0 */
int satellites_used; /* Number of satellites used in solution */
int used[MAXCHANNELS]; /* PRNs of satellites used in solution */
double pdop, hdop, vdop, tdop, gdop; /* Dilution of precision */
/* redundant with the estimate elments in the fix structure */
double epe; /* spherical position error, 95% confidence (meters) */
/* satellite status -- valid when satellites > 0 */
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-to-noise ratio (dB) */
#if 0 /* not yet used or filled in */
/* measurement data */
double pseudorange[MAXCHANNELS]; /* meters */
double deltarange[MAXCHANNELS]; /* meters/sec */
double doppler[MAXCHANNELS]; /* Hz */
unsigned satstat[MAXCHANNELS]; /* tracking status */
#define SAT_ACQUIRED 0x01 /* satellite acquired */
#define SAT_CODE_TRACK 0x02 /* code-tracking loop acquired */
#define SAT_CARR_TRACK 0x04 /* carrier-tracking loop acquired */
#define SAT_DATA_SYNC 0x08 /* data-bit synchronization done */
#define SAT_FRAME_SYNC 0x10 /* frame synchronization done */
#define SAT_EPHEMERIS 0x20 /* ephemeris collected */
#define SAT_FIX_USED 0x40 /* used for position fix */
#endif
#if defined(TNT_ENABLE) || defined(OCEANSERVER_ENABLE)
/* compass status -- TrueNorth (and any similar) devices only */
char headingStatus;
char pitchStatus;
char rollStatus;
double horzField; /* Magnitude of horizontal magnetic field */
#endif
#ifdef OCEANSERVER_ENABLE
double magnetic_length; /* unitvector sqrt(x^2 + y^2 +z^2) */
double magnetic_field_x;
double magnetic_field_y;
double magnetic_field_z;
double acceleration_length; /* unitvector sqrt(x^2 + y^2 +z^2) */
double acceleration_field_x;
double acceleration_field_y;
double acceleration_field_z;
double gyro_output_x;
double gyro_output_y;
double temperature;
#endif
/* where and what gpsd thinks the device is */
char gps_device[PATH_MAX]; /* only valid if non-null. */
char *gps_id; /* only valid if non-null. */
unsigned int baudrate, parity, stopbits; /* RS232 link parameters */
unsigned int driver_mode; /* whether driver is in native mode or not */
/* RTCM-104 data */
struct rtcm2_t rtcm2;
struct rtcm3_t rtcm3;
/* device list */
int ndevices; /* count of available devices */
char **devicelist; /* list of pathnames */
/* profiling data for last sentence */
bool profiling; /* profiling enabled? */
char tag[MAXTAGLEN+1]; /* tag of last sentence processed */
size_t sentence_length; /* character count of last sentence */
double sentence_time; /* sentence timestamp */
double d_xmit_time; /* beginning of sentence transmission */
double d_recv_time; /* daemon receipt time (-> E1+T1) */
double d_decode_time; /* daemon end-of-decode time (-> D1) */
double poll_time; /* daemon poll time (-> W) */
double emit_time; /* emission time (-> E2) */
double c_recv_time; /* client receipt time (-> T2) */
double c_decode_time; /* client end-of-decode time (-> D2) */
double cycle, mincycle; /* refresh cycle time in seconds */
/* these members are private */
int gps_fd; /* socket or file descriptor to GPS */
void (*raw_hook)(struct gps_data_t *, char *, size_t len, int level);/* Raw-mode hook for GPS data. */
void (*thread_hook)(struct gps_data_t *, char *, size_t len, int level);/* Thread-callback hook for GPS data. */
};
extern /*@null@*/ 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 *fmt, ... );
int gps_poll(struct gps_data_t *gpsdata);
void gps_set_raw_hook(struct gps_data_t *gpsdata, void (*hook)(struct gps_data_t *sentence, char *buf, size_t len, int level));
int gps_set_callback(struct gps_data_t *gpsdata, void (*callback)(struct gps_data_t *sentence, char *buf, size_t len, int level), pthread_t *handler);
int gps_del_callback(struct gps_data_t *gpsdata, pthread_t *handler);
enum unit {unspecified, imperial, nautical, metric};
enum unit gpsd_units(void);
enum deg_str_type { deg_dd, deg_ddmm, deg_ddmmss };
extern /*@observer@*/ char *deg_to_str( enum deg_str_type type, double f);
extern void gps_clear_fix(/*@ out @*/struct gps_fix_t *);
extern void gps_merge_fix(/*@ out @*/struct gps_fix_t *,
gps_mask_t,
/*@ in @*/struct gps_fix_t *);
extern unsigned int gps_valid_fields(/*@ in @*/struct gps_fix_t *);
extern char *gps_show_transfer(int);
extern time_t mkgmtime(register struct tm *);
extern double timestamp(void);
extern double iso8601_to_unix(char *);
extern /*@observer@*/char *unix_to_iso8601(double t, /*@ out @*/char[], size_t len);
extern double gpstime_to_unix(int, double);
extern void unix_to_gpstime(double, /*@out@*/int *, /*@out@*/double *);
extern double earth_distance(double, double, double, double);
extern double wgs84_separation(double, double);
/* some multipliers for interpreting GPS output */
#define METERS_TO_FEET 3.2808399 /* Meters to U.S./British feet */
#define METERS_TO_MILES 0.00062137119 /* Meters to miles */
#define KNOTS_TO_MPH 1.1507794 /* Knots to miles per hour */
#define KNOTS_TO_KPH 1.852 /* Knots to kilometers per hour */
#define KNOTS_TO_MPS 0.51444444 /* Knots to meters per second */
#define MPS_TO_KPH 3.6 /* Meters per second to klicks/hr */
#define MPS_TO_MPH 2.2369363 /* Meters/second to miles per hour */
#define MPS_TO_KNOTS 1.9438445 /* Meters per second to knots */
/* miles and knots are both the international standard versions of the units */
/* angle conversion multipliers */
#define GPS_PI 3.1415926535897932384626433832795029
#define RAD_2_DEG 57.2957795130823208767981548141051703
#define DEG_2_RAD 0.0174532925199432957692369076848861271
/* gps_open() errno 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 */
#define DEFAULT_RTCM_PORT "2101" /* IANA assignment */
#ifdef __cplusplus
} /* End of the 'extern "C"' block */
#endif
/* gps.h ends here */
#endif /* _GPSD_GPS_H_ */