ogr_structs.h

The OpenGPSRec receiver software runs on the real time operating system RTAI-Linux. It compiles with

/* ************************************************************************ 
   *                                                                      *
   *                            OpenGPS Receiver                          *
   *                                                                      *
   * -------------------------------------------------------------------- *
   *                                                                      *
   *    Module:   ogr_structs.h                                           *
   *                                                                      *
   *   Version:   0.1                                                     *
   *                                                                      *
   *      Date:   30.06.02                                                *
   *                                                                      *
   *    Author:   C. Kelley, G. Beyerle                                   *
   *                                                                      *
   * -------------------------------------------------------------------- *
   *                                                                      *
   * Copyright (C) 2001-2003  C. Kelley, G. Beyerle                       *
   *                                                                      *
   * This program is free software; you can redistribute it and/or modify *
   * it under the terms of the GNU General Public License as published by *
   * the Free Software Foundation; either version 2 of the License, or    *
   * (at your option) any later version.                                  *
   *                                                                      *
   * This program is distributed in the hope that it will be useful,      *
   * but WITHOUT ANY WARRANTY; without even the implied warranty of       *
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        *
   * GNU General Public License for more details.                         *
   *                                                                      *
   * You should have received a copy of the GNU General Public License    *
   * along with this program; if not, write to the Free Software          *
   * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.            *
   *                                                                      *
   * -------------------------------------------------------------------- *
   *                                                                      *
   * The files 'ogr_user.c', 'ogr_navdecode.c', 'ogr_navsolve.c',         *
   * 'ogr_rtproc.c' are modified versions of the files 'gpsfuncs.cpp',    *
   * 'gpsrcvr.cpp' from Clifford Kelley's OpenSourceGPS distribution.     *
   * The unmodified files can be obtained from                            *
   *             http://www.home.earthlink.net/~cwkelley                  *
   *                                                                      *
   * -------------------------------------------------------------------- *
   *                                                                      *
   *                              Structures                              *
   *                                                                      *
   ************************************************************************ */

/* ******************************* changes ********************************

   26.01.03 - add field 'page4' in CHN struct
              add fields 'accum_new', 'accum_missed' in struct 'PARAM'

   ************************************************************************ */

/* ----------------------------- structures ------------------------------- */

#if !defined( __OGR_STRUCTS_H__)

#define __OGR_STRUCTS_H__

// --- Approximate orbital parameters ---
typedef struct
{
  INT16  health,
         week,
         sat_file;
  double ety,              // eccentricity
         n0,               // mean motion (sqrt(GM/A^3))
         inc,              // inclination angle
         rra,              // rate of right ascension
         sqra,             // square root of semi-major axis
         lan,              // right ascension
         aop,              // argument of perigee
         ma,               // mean anomaly
         toa,              // time of applicability
         af0, af1;         // clock correction
  char   text_message[23]; // 22 ASCII chars + '\0'
} ALMANAC;

//  --- Precise orbital parameters ---
typedef struct
{
  INT16  iode,             // issue of date (ephemeris)
         iodc,             // issue of date (clock)
         ura,
         valid,
         health,
         week;
  double dn,               // mean motion - correction
         sqra,             // sqrt of semi-major axis
         W0,               // longitude of asc node
         Wdot,             // date of right ascension
         w,                // argument of perigee
         tgd,              // group dela differential
         toe,              // reference time ephemeris
         toc,              // sat clock data reference time [sec]
         inc0,             // inclination correction
         idot,
         cuc, cus, crc, crs, cic, cis, // 2nrd harmonic perturbation
         ma,               // mean anomaly
         n0,               // computed mean motion
//         e,
         ety,              // eccentricity
         af0, af1, af2;    // clock correction
} EPHEMERIS;

//  earth-centered earth-fixed co-ordinate system
typedef struct
{
  double x, y, z;
} ECEF;

typedef struct
{
  double lat, 
         lon, 
         hae;   // height above WGS-84 ellipsoid
} LLH;

/* --- variables referring to transmitter --- */
typedef struct
{
  INT16  as_and_config,    // anti-spoof and SV config
         health_status,    // SV health
         riseset;          // 1 : incr. elevation; -1 : decr. elevation
  ECEF   pos;              // position in ECEF
  double azimuth,          // azimuth [rad]
         elevation,        // elevation [deg]
         doppler, 
         xmit_clock_corr;
} XMITINFO;

/* --- variables referring to receiver --- */
typedef struct
{
  ECEF   pos; 
  LLH    llh;
  double rcvr_clock_corr,
         speed,
         heading;
} RCVRINFO;

typedef struct
{
   double x, y, z, 
          dt,
          xv, yv, zv, 
          df;
} PVT;

// --- correlator GP2021 channel info ---
typedef struct
{
  long   cod_frq,           // frq of code DCO in units of 42.6 mHz
         car_frq,           // frq of carrier DCO in units of 42.6 mHz
         car_corr,          // correction due to doppler & clock error
//         cod_phs,           // code phase
//         car_phs,           // carrier phase
         i_prompt_20ms,     // I prompt summed over 20 ms
         q_prompt_20ms,     // Q prompt summed over 20 ms
         i_dith_20ms,       // I dither summed over 20 ms
         q_dith_20ms,       // Q dither summed over 20 ms  
         i_pd_20ms,         // sum over 20mc for C/N0 estimate
         qq_pd_20ms,
         avg_20ms,
         tow_HOW,           // time of week as read from HOW [units of 1 s]
         tow;               // 'tow_HOW' is copied to 'tow' at start of next subframe
  INT16  state,             // state: acquisition/pull-in/tracking/...
         tow_sync,          // preamble is successfully decoded tow_HOW is set
         prn,               // PRN attached to this channel
         cod_slew,          // C/A code slew at next DUMP
         n_freq,            // index in carrier frq list, 1 step corresponds to frq shift 'delta_freq'
         delta_frq,         // freq step for doppler search
         i_prompt,          // in-phase prompt arm
         q_prompt,          // quad-phase promt arm
         i_dith,            // in-phase early/late arm
         q_dith,            // quad-phase early/late arm
         hidx;              // index in hist20ms[]
  UINT16 bit_count,         // bit counter, 0,...,1499
         frame_count,       // frame counter (overflows after 22.7 days)
//         pull_in_count,     // pull in timer [ms]  (ch_pull_in())
//         confirm_count,     // confirm timer (ch_confirm())
//         confirm_above_thresh, // above threshold counter (ch_confirm())
         sfid,              // subframe id: 1,...,5
         TLM,               // reserved TLM field
         missed,            // number of missed DUMPs
         page4,
         page5,
         code_slew,         // # halfchips to be slewed at next DUMP event
         code_phase,        // code phase: 0,...,2046 halfchips
         code_dco_phase,    // code fract. phase: 0,...,1023, 1024 = halfchip
         carr_dco_phase,    // carr fract. phase: 0,...,1023
         carr_cycle_lo,     // carrier cycle low word
         carr_cycle_hi,     // carrier cycle high word
         epoch,             // bit 13-8: 20 ms epoch, 0,...,49
                            // bit 4-0: 1 ms epoch, 0,...,19
                            // sampled at last TIC