| /* |
| * ubx-parse.c |
| * |
| * Implementation of parsing code converting UBX messages to GPS assist |
| * data |
| * |
| * |
| * Copyright (C) 2009 Sylvain Munaut <tnt@246tNt.com> |
| * |
| * 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, see <http://www.gnu.org/licenses/>. |
| */ |
| |
| #include <stdio.h> |
| |
| #include "gps.h" |
| #include "ubx.h" |
| #include "ubx-parse.h" |
| |
| |
| /* Helpers */ |
| |
| static int |
| float_to_fixedpoint(float f, int sf) |
| { |
| if (sf < 0) { |
| while (sf++ < 0) |
| f *= 2.0f; |
| } else { |
| while (sf-- > 0) |
| f *= 0.5f; |
| } |
| |
| return (int)f; |
| } |
| |
| static inline int |
| double_to_fixedpoint(double d, int sf) |
| { |
| if (sf < 0) { |
| while (sf++ < 0) |
| d *= 2.0; |
| } else { |
| while (sf-- > 0) |
| d *= 0.5; |
| } |
| |
| return (int)d; |
| } |
| |
| |
| /* UBX message parsing to fill gps assist data */ |
| |
| static void |
| _ubx_msg_parse_nav_posllh(struct ubx_hdr *hdr, void *pl, int pl_len, void *ud) |
| { |
| struct ubx_nav_posllh *nav_posllh = pl; |
| struct gps_assist_data *gps = ud; |
| |
| //printf("[.] NAV_POSLLH\n"); |
| |
| gps->fields |= GPS_FIELD_REFPOS; |
| |
| gps->ref_pos.latitude = (double)(nav_posllh->lat) * 1e-7; |
| gps->ref_pos.longitude = (double)(nav_posllh->lon) * 1e-7; |
| gps->ref_pos.altitude = (double)(nav_posllh->height) * 1e-3; |
| } |
| |
| static void |
| _ubx_msg_parse_aid_ini(struct ubx_hdr *hdr, void *pl, int pl_len, void *ud) |
| { |
| struct ubx_aid_ini *aid_ini = pl; |
| struct gps_assist_data *gps = ud; |
| |
| //printf("[.] AID_INI\n"); |
| |
| /* Extract info for "Reference Time" */ |
| gps->fields |= GPS_FIELD_REFTIME; |
| |
| gps->ref_time.wn = aid_ini->wn; |
| gps->ref_time.tow = (double)aid_ini->tow * 1e-3; |
| |
| // FIXME: We could extract ref position as well but we need it in |
| // WGS84 geodetic coordinates and it's provided as ecef, so |
| // we need a lot of math ... |
| } |
| |
| static void |
| _ubx_msg_parse_aid_hui(struct ubx_hdr *hdr, void *pl, int pl_len, void *ud) |
| { |
| struct ubx_aid_hui *aid_hui = pl; |
| struct gps_assist_data *gps = ud; |
| |
| //printf("[.] AID_HUI\n"); |
| |
| if (aid_hui->flags & 0x2) { /* UTC parameters valid */ |
| struct gps_utc_model *utc = &gps->utc; |
| |
| gps->fields |= GPS_FIELD_UTC; |
| |
| utc->a0 = double_to_fixedpoint(aid_hui->utc_a0, -30); |
| utc->a1 = double_to_fixedpoint(aid_hui->utc_a1, -50); |
| utc->delta_t_ls = aid_hui->utc_ls; |
| utc->t_ot = aid_hui->utc_tot >> 12; |
| utc->wn_t = aid_hui->utc_wnt; |
| utc->wn_lsf = aid_hui->utc_wnf; |
| utc->dn = aid_hui->utc_dn; |
| utc->delta_t_lsf = aid_hui->utc_lsf; |
| } |
| |
| if (aid_hui->flags & 0x04) { /* Klobuchar parameters valid */ |
| struct gps_ionosphere_model *iono = &gps->ionosphere; |
| |
| gps->fields |= GPS_FIELD_IONOSPHERE; |
| |
| iono->alpha_0 = float_to_fixedpoint(aid_hui->klob_a0, -30); |
| iono->alpha_1 = float_to_fixedpoint(aid_hui->klob_a1, -27); |
| iono->alpha_2 = float_to_fixedpoint(aid_hui->klob_a2, -24); |
| iono->alpha_3 = float_to_fixedpoint(aid_hui->klob_a3, -24); |
| iono->beta_0 = float_to_fixedpoint(aid_hui->klob_b0, 11); |
| iono->beta_1 = float_to_fixedpoint(aid_hui->klob_b1, 14); |
| iono->beta_2 = float_to_fixedpoint(aid_hui->klob_b2, 16); |
| iono->beta_3 = float_to_fixedpoint(aid_hui->klob_b3, 16); |
| } |
| } |
| |
| static void |
| _ubx_msg_parse_aid_alm(struct ubx_hdr *hdr, void *pl, int pl_len, void *ud) |
| { |
| struct ubx_aid_alm *aid_alm = pl; |
| struct gps_assist_data *gps = ud; |
| |
| //printf("[.] AID_ALM %d - %d\n", aid_alm->sv_id, aid_alm->gps_week); |
| |
| if (aid_alm->gps_week) { |
| gps->fields |= GPS_FIELD_ALMANAC; |
| gps->almanac.wna = aid_alm->gps_week & 0xff; |
| gps_unpack_sf45_almanac(aid_alm->alm_words, &gps->almanac.svs[gps->almanac.n_sv++]); |
| } |
| } |
| |
| static void |
| _ubx_msg_parse_aid_eph(struct ubx_hdr *hdr, void *pl, int pl_len, void *ud) |
| { |
| struct ubx_aid_eph *aid_eph = pl; |
| struct gps_assist_data *gps = ud; |
| |
| //printf("[.] AID_EPH %d - %s\n", aid_eph->sv_id, aid_eph->present ? "present" : "not present"); |
| |
| if (aid_eph->present) { |
| int i = gps->ephemeris.n_sv++; |
| gps->fields |= GPS_FIELD_EPHEMERIS; |
| gps->ephemeris.svs[i].sv_id = aid_eph->sv_id; |
| gps_unpack_sf123(aid_eph->eph_words, &gps->ephemeris.svs[i]); |
| } |
| } |
| |
| |
| /* Dispatch table */ |
| struct ubx_dispatch_entry ubx_parse_dt[] = { |
| UBX_DISPATCH(NAV, POSLLH, _ubx_msg_parse_nav_posllh), |
| UBX_DISPATCH(AID, INI, _ubx_msg_parse_aid_ini), |
| UBX_DISPATCH(AID, HUI, _ubx_msg_parse_aid_hui), |
| UBX_DISPATCH(AID, ALM, _ubx_msg_parse_aid_alm), |
| UBX_DISPATCH(AID, EPH, _ubx_msg_parse_aid_eph), |
| }; |
| |