gpstime.h File Reference

#include <time.h>
#include "common.h"

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Defines
#define	GPS_EPOCH   315964800
#define	GPS_MINUS_UTC_SECS   16
#define	GPS_WEEK_CYCLE   1
Functions
struct	__attribute__ ((packed))
time_t	gps2time (gps_time_t t)
double	gpsdifftime (gps_time_t end, gps_time_t beginning)
gps_time_t	normalize_gps_time (gps_time_t)
Variables
	gps_time_t

---

Define Documentation

#define GPS_EPOCH   315964800

Unix timestamp of the GPS epoch 1980-01-06 00:00:00 UTC

Definition at line 31 of file gpstime.h.

#define GPS_MINUS_UTC_SECS   16

Offset between GPS and UTC times in seconds. Update when a new leap second is inserted and be careful about times in the past when this offset was different.

Definition at line 28 of file gpstime.h.

#define GPS_WEEK_CYCLE   1

Number of rollovers in the 10-bit broadcast GPS week number. Update on next rollover on April 7, 2019.

Todo:

Detect and handle rollover more gracefully.

Definition at line 23 of file gpstime.h.

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Function Documentation

struct __attribute__

(

(packed)

)

[read]

Structure representing a GPS time.

< Seconds since the GPS start of week.

< GPS week number.

Definition at line 34 of file gpstime.h.

time_t gps2time

(

gps_time_t

gps_t

)

Convert a `gps_time_t` GPS time to a Unix `time_t`.

Note:

Adjusts for leap seconds using the current constant offset.

Parameters:

t	GPS time struct.

Returns:

Unix time.

Definition at line 45 of file gpstime.c.

double gpsdifftime	(	gps_time_t	end,
		gps_time_t	beginning
	)

Time difference in seconds between two GPS times.

Parameters:

end	Higher bound of the time interval whose length is calculated.
beginning	Lower bound of the time interval whose length is calculated. If this describes a time point later than end, the result is negative.

Returns:

The time difference in seconds between `beginning` and `end`.

Definition at line 62 of file gpstime.c.

gps_time_t normalize_gps_time

(

gps_time_t

t

)

Normalize a `gps_time_t` GPS time struct. Ensures that the time of week is greater than zero and less than one week by wrapping and adjusting the week number accordingly.

Parameters:

t	GPS time struct.

Returns:

Normalized GPS time struct.

Definition at line 24 of file gpstime.c.

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Variable Documentation

gps_time_t

Definition at line 37 of file gpstime.h.