ubx.h

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#ifndef STAR_UBX_H
#define STAR_UBX_H
 
/*
 * u-blox UBX protocol pieces for the MAX-M10S (MD1). Interface Description
 * "u-blox M10 SPG 5.10", UBX-21035062 R02:
 *   frame      B5 62 class id len16 payload CK_A CK_B, 8-bit Fletcher over
 *              class..payload
 *   VALSET     0x06 0x8A: version 0, layers, 2 reserved, key/value pairs
 *              (3.10.5.1, p.55); this code writes the RAM layer only, so the
 *              configuration is re-sent on every power-up
 *   ACK        0x05 0x01 ACK / 0x05 0x00 NAK, payload = acked class, id
 *   NAV-PVT    0x01 0x07, 92 bytes (3.15.11, p.95)
 *   NAV-SAT    0x01 0x35, 8 + numSvs*12 bytes (3.15.13, p.98)
 *   MON-RF     0x0A 0x38, 4 + nBlocks*24 bytes (3.14.6, p.86)
 *   A message with an empty payload polls the module for that message.
 * Keys used (Section 6, p.136-154): CFG-UART1-BAUDRATE 0x40520001 U4,
 * CFG-UART1OUTPROT-NMEA 0x10740002 L, CFG-MSGOUT-UBX_NAV_PVT_UART1
 * 0x20910007 U1, CFG-RATE-MEAS 0x30210001 U2 (ms), CFG-NAVSPG-DYNMODEL
 * 0x20110021 E1 (AIR4 = 8, "airborne <4g", Table 23 p.141).
 */
 
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
 
#ifdef __cplusplus
extern "C" {
#endif
 
#define UBX_CLASS_NAV 0x01U
#define UBX_CLASS_ACK 0x05U
#define UBX_CLASS_CFG 0x06U
#define UBX_CLASS_MON 0x0AU
#define UBX_ID_NAV_PVT 0x07U
#define UBX_ID_NAV_SAT 0x35U
#define UBX_ID_MON_RF 0x38U
#define UBX_ID_ACK_ACK 0x01U
#define UBX_ID_ACK_NAK 0x00U
#define UBX_ID_CFG_VALSET 0x8AU
#define UBX_NAV_PVT_LEN 92U
 
#define UBX_KEY_UART1_BAUDRATE 0x40520001UL
#define UBX_KEY_UART1OUTPROT_NMEA 0x10740002UL
#define UBX_KEY_MSGOUT_NAV_PVT_UART1 0x20910007UL
#define UBX_KEY_RATE_MEAS 0x30210001UL
#define UBX_KEY_NAVSPG_DYNMODEL 0x20110021UL
#define UBX_DYNMODEL_AIR4 8U
 
typedef struct {
    uint32_t key;
    uint8_t size; /* 1, 2 or 4 bytes (L/U1/E1, U2, U4) */
    uint32_t value;
} ubx_item_t;
 
/* Whole frame into out; returns its length, 0 if it does not fit. */
size_t ubx_frame(uint8_t* out, size_t cap, uint8_t cls, uint8_t id,
                 const uint8_t* payload, uint16_t len);
 
/* UBX-CFG-VALSET to the RAM layer; returns frame length, 0 on error. */
size_t ubx_valset(uint8_t* out, size_t cap, const ubx_item_t* items,
                  size_t count);
 
typedef struct {
    uint32_t itow_ms;
    uint16_t year;
    uint8_t month, day, hour, min, sec, valid;
    uint8_t fix_type; /* 0 none, 2 2D, 3 3D */
    uint8_t flags;    /* bit 0 gnssFixOK */
    uint8_t num_sv;
    int32_t lon_e7, lat_e7; /* 1e-7 deg */
    int32_t height_mm, hmsl_mm;
    uint32_t hacc_mm, vacc_mm;
    int32_t vel_n_mms, vel_e_mms, vel_d_mms;
    uint32_t sacc_mms;
    uint16_t pdop_e2;
} ubx_pvt_t;
 
/* Decode a NAV-PVT payload (exactly 92 bytes). */
bool ubx_parse_nav_pvt(const uint8_t* payload, uint16_t len, ubx_pvt_t* out);
 
/* A poll request (the message with no payload); returns frame length. */
size_t ubx_poll(uint8_t* out, size_t cap, uint8_t cls, uint8_t id);
 
/* MON-RF antenna supervisor values (3.14.6, p.86) */
#define UBX_ANT_INIT 0U
#define UBX_ANT_DONTKNOW 1U
#define UBX_ANT_OK 2U
#define UBX_ANT_SHORT 3U
#define UBX_ANT_OPEN 4U
#define UBX_ANT_POWER_OFF 0U
#define UBX_ANT_POWER_ON 1U
#define UBX_ANT_POWER_DONTKNOW 2U
 
/* MON-RF, first RF block (L1, the only band on the MAX-M10S). */
typedef struct {
    uint8_t ant_status; /* UBX_ANT_* */
    uint8_t ant_power;  /* UBX_ANT_POWER_* */
    uint8_t jamming;    /* 0 unknown, 1 ok, 2 warning, 3 critical */
    uint8_t cw;         /* CW jamming suppression, 0 none .. 255 strong */
    uint16_t noise;     /* noisePerMS */
    uint16_t agc;       /* agcCnt, 0..8191 */
} ubx_rf_t;
 
/* Decode a MON-RF payload with at least one RF block. */
bool ubx_parse_mon_rf(const uint8_t* payload, uint16_t len, ubx_rf_t* out);
 
/* NAV-SAT condensed to counts. `len` may be a captured prefix of the
 * payload: `listed` is the module's numSvs, the rest count only the SVs
 * whose 12-byte blocks are within `len` (`seen` of them). */
typedef struct {
    uint8_t listed;      /* numSvs: known visible or tracked */
    uint8_t seen;        /* blocks decoded (< listed if truncated) */
    uint8_t with_signal; /* cno > 0 */
    uint8_t locked;      /* qualityInd >= 4: code locked, time synced */
    uint8_t used;        /* svUsed: in the navigation solution */
    uint8_t best_cno;    /* strongest C/N0, dB-Hz */
} ubx_sats_t;
 
bool ubx_sat_summary(const uint8_t* payload, uint16_t len, ubx_sats_t* out);
 
#ifdef __cplusplus
}
#endif
#endif