ardupilot/libraries/AP_GPS/AP_GPS_UBLOX.h

// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: t -*-
//
//  u-blox UBX GPS driver for ArduPilot and ArduPilotMega.
//	Code by Michael Smith, Jordi Munoz and Jose Julio, DIYDrones.com
//
//	This library is free software; you can redistribute it and / or
//	modify it under the terms of the GNU Lesser General Public
//	License as published by the Free Software Foundation; either
//	version 2.1 of the License, or (at your option) any later version.
//
#ifndef AP_GPS_UBLOX_h
#define AP_GPS_UBLOX_h

#include "GPS.h"

#define UBLOX_SET_BINARY	"$PUBX,41,1,0003,0001,38400,0*26"

class AP_GPS_UBLOX : public GPS
{
public:
    // Methods
    AP_GPS_UBLOX(Stream *s);
    virtual void	init();
    virtual bool	read();

private:
    // u-blox UBX protocol essentials
// XXX this is being ignored by the compiler #pragma pack(1)
    struct ubx_nav_posllh {
        uint32_t	time;				// GPS msToW
        int32_t		longitude;
        int32_t		latitude;
        int32_t		altitude_ellipsoid;
        int32_t		altitude_msl;
        uint32_t	horizontal_accuracy;
        uint32_t	vertical_accuracy;
    };
    struct ubx_nav_status {
        uint32_t	time;				// GPS msToW
        uint8_t		fix_type;
        uint8_t		fix_status;
        uint8_t		differential_status;
        uint8_t		res;
        uint32_t	time_to_first_fix;
        uint32_t	uptime;				// milliseconds
    };
    struct ubx_nav_solution {
        uint32_t	time;
        int32_t		time_nsec;
        int16_t		week;
        uint8_t		fix_type;
        uint8_t		fix_status;
        int32_t		ecef_x;
        int32_t		ecef_y;
        int32_t		ecef_z;
        uint32_t	position_accuracy_3d;
        int32_t		ecef_x_velocity;
        int32_t		ecef_y_velocity;
        int32_t		ecef_z_velocity;
        uint32_t	speed_accuracy;
        uint16_t	position_DOP;
        uint8_t		res;
        uint8_t		satellites;
        uint32_t	res2;
    };
    struct ubx_nav_velned {
        uint32_t	time;				// GPS msToW
        int32_t		ned_north;
        int32_t		ned_east;
        int32_t		ned_down;
        uint32_t	speed_3d;
        uint32_t	speed_2d;
        int32_t		heading_2d;
        uint32_t	speed_accuracy;
        uint32_t	heading_accuracy;
    };
// // #pragma pack(pop)
    enum ubs_protocol_bytes {
        PREAMBLE1 = 0xb5,
        PREAMBLE2 = 0x62,
        CLASS_NAV = 0x1,
        MSG_POSLLH = 0x2,
        MSG_STATUS = 0x3,
        MSG_SOL = 0x6,
        MSG_VELNED = 0x12
    };
    enum ubs_nav_fix_type {
        FIX_NONE = 0,
        FIX_DEAD_RECKONING = 1,
        FIX_2D = 2,
        FIX_3D = 3,
        FIX_GPS_DEAD_RECKONING = 4,
        FIX_TIME = 5
    };
    enum ubx_nav_status_bits {
        NAV_STATUS_FIX_VALID = 1
    };

    // Packet checksum accumulators
    uint8_t		_ck_a;
    uint8_t		_ck_b;

    // State machine state
    uint8_t		_step;
    uint8_t		_msg_id;
    bool   		_gather;
    uint16_t	_expect;
    uint16_t	_payload_length;
    uint16_t	_payload_counter;

	// do we have new position information?
	bool		_new_position;

	// do we have new speed information?
	bool		_new_speed;

    // Receive buffer
    union {
        ubx_nav_posllh		posllh;
        ubx_nav_status		status;
        ubx_nav_solution	solution;
        ubx_nav_velned		velned;
        uint8_t	bytes[];
    } _buffer;

    // Buffer parse & GPS state update
    bool		_parse_gps();

	// used to update fix between status and position packets
	bool next_fix;
};

#endif