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Diffstat (limited to 'src/fsm/minmea.h')
| -rw-r--r-- | src/fsm/minmea.h | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/src/fsm/minmea.h b/src/fsm/minmea.h new file mode 100644 index 0000000..6d7fe18 --- /dev/null +++ b/src/fsm/minmea.h @@ -0,0 +1,234 @@ +/* + * Copyright © 2014 Kosma Moczek <kosma@cloudyourcar.com> + * This program is free software. It comes without any warranty, to the extent + * permitted by applicable law. You can redistribute it and/or modify it under + * the terms of the Do What The Fuck You Want To Public License, Version 2, as + * published by Sam Hocevar. See the COPYING file for more details. + */ + +#ifndef MINMEA_H +#define MINMEA_H + +#ifdef __cplusplus +extern "C" { +#endif + +#include <stdio.h> +#include <stdint.h> +#include <stdbool.h> +#include <errno.h> +#include <time.h> +#include <math.h> + +#define MINMEA_MAX_LENGTH 80 + +enum minmea_sentence_id { + MINMEA_INVALID = -1, + MINMEA_UNKNOWN = 0, + MINMEA_SENTENCE_RMC, + MINMEA_SENTENCE_GGA, + MINMEA_SENTENCE_GSA, + MINMEA_SENTENCE_GLL, + MINMEA_SENTENCE_GST, + MINMEA_SENTENCE_GSV, +}; + +struct minmea_float { + int_least32_t value; + int_least32_t scale; +}; + +struct minmea_date { + int day; + int month; + int year; +}; + +struct minmea_time { + int hours; + int minutes; + int seconds; + int microseconds; +}; + +struct minmea_sentence_rmc { + struct minmea_time time; + bool valid; + struct minmea_float latitude; + struct minmea_float longitude; + struct minmea_float speed; + struct minmea_float course; + struct minmea_date date; + struct minmea_float variation; +}; + +struct minmea_sentence_gga { + struct minmea_time time; + struct minmea_float latitude; + struct minmea_float longitude; + int fix_quality; + int satellites_tracked; + struct minmea_float hdop; + struct minmea_float altitude; char altitude_units; + struct minmea_float height; char height_units; + int dgps_age; +}; + +enum minmea_gll_status { + MINMEA_GLL_STATUS_DATA_VALID = 'A', + MINMEA_GLL_STATUS_DATA_NOT_VALID = 'V', +}; + +enum minmea_gll_mode { + MINMEA_GLL_MODE_AUTONOMOUS = 'A', + MINMEA_GLL_MODE_DPGS = 'D', + MINMEA_GLL_MODE_DR = 'E', +}; + +struct minmea_sentence_gll { + struct minmea_float latitude; + struct minmea_float longitude; + struct minmea_time time; + char status; + char mode; +}; + +struct minmea_sentence_gst { + struct minmea_time time; + struct minmea_float rms_deviation; + struct minmea_float semi_major_deviation; + struct minmea_float semi_minor_deviation; + struct minmea_float semi_major_orientation; + struct minmea_float latitude_error_deviation; + struct minmea_float longitude_error_deviation; + struct minmea_float altitude_error_deviation; +}; + +enum minmea_gsa_mode { + MINMEA_GPGSA_MODE_AUTO = 'A', + MINMEA_GPGSA_MODE_FORCED = 'M', +}; + +enum minmea_gsa_fix_type { + MINMEA_GPGSA_FIX_NONE = 1, + MINMEA_GPGSA_FIX_2D = 2, + MINMEA_GPGSA_FIX_3D = 3, +}; + +struct minmea_sentence_gsa { + char mode; + int fix_type; + int sats[12]; + struct minmea_float pdop; + struct minmea_float hdop; + struct minmea_float vdop; +}; + +struct minmea_sat_info { + int nr; + int elevation; + int azimuth; + int snr; +}; + +struct minmea_sentence_gsv { + int total_msgs; + int msg_nr; + int total_sats; + struct minmea_sat_info sats[4]; +}; + +/** + * Calculate raw sentence checksum. Does not check sentence integrity. + */ +uint8_t minmea_checksum(const char *sentence); + +/** + * Check sentence validity and checksum. Returns true for valid sentences. + */ +bool minmea_check(const char *sentence, bool strict); + +/** + * Determine talker identifier. + */ +bool minmea_talker_id(char talker[3], const char *sentence); + +/** + * Determine sentence identifier. + */ +enum minmea_sentence_id minmea_sentence_id(const char *sentence, bool strict); + +/** + * Scanf-like processor for NMEA sentences. Supports the following formats: + * c - single character (char *) + * d - direction, returned as 1/-1, default 0 (int *) + * f - fractional, returned as value + scale (int *, int *) + * i - decimal, default zero (int *) + * s - string (char *) + * t - talker identifier and type (char *) + * T - date/time stamp (int *, int *, int *) + * Returns true on success. See library source code for details. + */ +bool minmea_scan(const char *sentence, const char *format, ...); + +/* + * Parse a specific type of sentence. Return true on success. + */ +bool minmea_parse_rmc(struct minmea_sentence_rmc *frame, const char *sentence); +bool minmea_parse_gga(struct minmea_sentence_gga *frame, const char *sentence); +bool minmea_parse_gsa(struct minmea_sentence_gsa *frame, const char *sentence); +bool minmea_parse_gll(struct minmea_sentence_gll *frame, const char *sentence); +bool minmea_parse_gst(struct minmea_sentence_gst *frame, const char *sentence); +bool minmea_parse_gsv(struct minmea_sentence_gsv *frame, const char *sentence); + +/** + * Convert GPS UTC date/time representation to a UNIX timestamp. + */ +int minmea_gettime(struct timespec *ts, const struct minmea_date *date, const struct minmea_time *time_); + +/** + * Rescale a fixed-point value to a different scale. Rounds towards zero. + */ +static inline int_least32_t minmea_rescale(struct minmea_float *f, int_least32_t new_scale) +{ + if (f->scale == 0) + return 0; + if (f->scale == new_scale) + return f->value; + if (f->scale > new_scale) + return (f->value + ((f->value > 0) - (f->value < 0)) * f->scale/new_scale/2) / (f->scale/new_scale); + else + return f->value * (new_scale/f->scale); +} + +/** + * Convert a fixed-point value to a floating-point value. + * Returns NaN for "unknown" values. + */ +static inline float minmea_tofloat(struct minmea_float *f) +{ + if (f->scale == 0) + return NAN; + return (float) f->value / (float) f->scale; +} + +/** + * Convert a raw coordinate to a floating point DD.DDD... value. + * Returns NaN for "unknown" values. + */ +static inline float minmea_tocoord(struct minmea_float *f) +{ + if (f->scale == 0) + return NAN; + int_least32_t degrees = f->value / (f->scale * 100); + int_least32_t minutes = f->value % (f->scale * 100); + return (float) degrees + (float) minutes / (60 * f->scale); +} + +#ifdef __cplusplus +} +#endif + +#endif /* MINMEA_H */ + +/* vim: set ts=4 sw=4 et: */ |