mirror of
https://github.com/csete/gpredict
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65b85b17b7
git-svn-id: https://gpredict.svn.sourceforge.net/svnroot/gpredict/trunk@697 ab6734ba-2843-0410-b83b-99c217ef6c0f
128 lines
3.4 KiB
C
128 lines
3.4 KiB
C
/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/*
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Gpredict: Real-time satellite tracking and orbit prediction program
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Copyright (C) 2001-2009 Alexandru Csete, OZ9AEC.
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Authors: Alexandru Csete <oz9aec@gmail.com>
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Comments, questions and bugreports should be submitted via
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http://sourceforge.net/projects/gpredict/
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More details can be found at the project home page:
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http://gpredict.oz9aec.net/
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, visit http://www.fsf.org/
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*/
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/** \brief Satellite visibility calculations. */
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#include <gtk/gtk.h>
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#include <glib/gi18n.h>
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#include "sgpsdp/sgp4sdp4.h"
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#include "gtk-sat-data.h"
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#include "sat-vis.h"
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#include "sat-cfg.h"
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static gchar VIS2CHR[SAT_VIS_NUM] = { '-', 'V', 'D', 'E'};
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static gchar *VIS2STR[SAT_VIS_NUM] = {
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N_("Unknown"),
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N_("Visible"),
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N_("Daylight"),
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N_("Eclipsed")
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};
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/** \brief Calculate satellite visibility.
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* \param sat The satellite structure.
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* \param qth The QTH
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* \param jul_utc The time at which the visibility should be calculated.
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* \return The visiblity code.
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*
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*/
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sat_vis_t
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get_sat_vis (sat_t *sat, qth_t *qth, gdouble jul_utc)
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{
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gboolean sat_sun_status;
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gdouble sun_el;
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gdouble threshold;
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gdouble eclipse_depth;
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sat_vis_t vis = SAT_VIS_NONE;
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vector_t zero_vector = {0,0,0,0};
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geodetic_t obs_geodetic;
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/* Solar ECI position vector */
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vector_t solar_vector=zero_vector;
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/* Solar observed az and el vector */
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obs_set_t solar_set;
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/* FIXME: could be passed as parameter */
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obs_geodetic.lon = qth->lon * de2ra;
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obs_geodetic.lat = qth->lat * de2ra;
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obs_geodetic.alt = qth->alt / 1000.0;
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obs_geodetic.theta = 0;
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Calculate_Solar_Position (jul_utc, &solar_vector);
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Calculate_Obs (jul_utc, &solar_vector, &zero_vector, &obs_geodetic, &solar_set);
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if (Sat_Eclipsed (&sat->pos, &solar_vector, &eclipse_depth)) {
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/* satellite is eclipsed */
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sat_sun_status = FALSE;
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}
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else {
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/* satellite in sunlight => may be visible */
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sat_sun_status = TRUE;
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}
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if (sat_sun_status) {
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sun_el = Degrees (solar_set.el);
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threshold = (gdouble) sat_cfg_get_int (SAT_CFG_INT_PRED_TWILIGHT_THLD);
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if (sun_el <= threshold && sat->el >= 0.0)
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vis = SAT_VIS_VISIBLE;
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else
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vis = SAT_VIS_DAYLIGHT;
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}
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else
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vis = SAT_VIS_ECLIPSED;
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return vis;
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}
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/** \brief Convert visibility to character code. */
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gchar
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vis_to_chr (sat_vis_t vis)
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{
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return VIS2CHR[vis];
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}
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/** \brief Convert visibility to character string.
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* \param vis The visibility code
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*
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* The returned string must be freed when no longer needed.
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*/
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gchar *
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vis_to_str (sat_vis_t vis)
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{
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return g_strdup (_(VIS2STR[vis]));
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}
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