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<?php |
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/* |
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A limited PHP port of the gpredict program, done by Bill Shupp. |
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Original notes and author information is below. GPL2 license. |
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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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Parts are Copyright John A. Magliacane, KD2BD 1991-2003 (indicated below) |
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Authors: Alexandru Csete <[email protected]> |
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John A. Magliacane, KD2BD. |
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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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require_once 'Predict/Time.php'; |
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require_once 'Predict/Math.php'; |
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require_once 'Predict/Pass.php'; |
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require_once 'Predict/PassDetail.php'; |
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require_once 'Predict/Vector.php'; |
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require_once 'Predict/Geodetic.php'; |
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require_once 'Predict/ObsSet.php'; |
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require_once 'Predict/Solar.php'; |
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require_once 'Predict/SGPObs.php'; |
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require_once 'Predict/SGPSDP.php'; |
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/** |
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* The main Predict class. Contains constants for use by other classes, as well as |
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* the prediction logic. |
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*/ |
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class Predict |
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{ |
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const de2ra = 1.74532925E-2; /* Degrees to Radians */ |
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const pi = 3.1415926535898; /* Pi */ |
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const pio2 = 1.5707963267949; /* Pi/2 */ |
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const x3pio2 = 4.71238898; /* 3*Pi/2 */ |
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const twopi = 6.2831853071796; /* 2*Pi */ |
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const e6a = 1.0E-6; |
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const tothrd = 6.6666667E-1; /* 2/3 */ |
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const xj2 = 1.0826158E-3; /* J2 Harmonic */ |
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const xj3 = -2.53881E-6; /* J3 Harmonic */ |
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const xj4 = -1.65597E-6; /* J4 Harmonic */ |
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const xke = 7.43669161E-2; |
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const xkmper = 6.378135E3; /* Earth radius km */ |
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const xmnpda = 1.44E3; /* Minutes per day */ |
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const km2mi = 0.621371; /* Kilometers per Mile */ |
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const ae = 1.0; |
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const ck2 = 5.413079E-4; |
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const ck4 = 6.209887E-7; |
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const __f = 3.352779E-3; |
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const ge = 3.986008E5; |
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const __s__ = 1.012229; |
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const qoms2t = 1.880279E-09; |
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const secday = 8.6400E4; /* Seconds per day */ |
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const omega_E = 1.0027379; |
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const omega_ER = 6.3003879; |
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const zns = 1.19459E-5; |
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const c1ss = 2.9864797E-6; |
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const zes = 1.675E-2; |
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const znl = 1.5835218E-4; |
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const c1l = 4.7968065E-7; |
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const zel = 5.490E-2; |
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const zcosis = 9.1744867E-1; |
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const zsinis = 3.9785416E-1; |
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const zsings = -9.8088458E-1; |
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const zcosgs = 1.945905E-1; |
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const zcoshs = 1; |
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const zsinhs = 0; |
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const q22 = 1.7891679E-6; |
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const q31 = 2.1460748E-6; |
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const q33 = 2.2123015E-7; |
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const g22 = 5.7686396; |
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const g32 = 9.5240898E-1; |
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const g44 = 1.8014998; |
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const g52 = 1.0508330; |
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const g54 = 4.4108898; |
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const root22 = 1.7891679E-6; |
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const root32 = 3.7393792E-7; |
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const root44 = 7.3636953E-9; |
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const root52 = 1.1428639E-7; |
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const root54 = 2.1765803E-9; |
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const thdt = 4.3752691E-3; |
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const rho = 1.5696615E-1; |
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const mfactor = 7.292115E-5; |
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const __sr__ = 6.96000E5; /*Solar radius - kilometers (IAU 76)*/ |
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const AU = 1.49597870E8; /*Astronomical unit - kilometers (IAU 76)*/ |
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/* visibility constants */ |
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const SAT_VIS_NONE = 0; |
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const SAT_VIS_VISIBLE = 1; |
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const SAT_VIS_DAYLIGHT = 2; |
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const SAT_VIS_ECLIPSED = 3; |
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/* preferences */ |
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public $minEle = 10; // Minimum elevation |
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public $timeRes = 10; // Pass details: time resolution |
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public $numEntries = 20; // Pass details: number of entries |
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public $threshold = -6; // Twilight threshold |
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/** |
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* Predict the next pass. |
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* |
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* This function simply wraps the get_pass function using the current time |
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* as parameter. |
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* |
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* Note: the data in sat will be corrupt (future) and must be refreshed |
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* by the caller, if the caller will need it later on (eg. if the caller |
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* is GtkSatList). |
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* |
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* @param Predict_Sat $sat The satellite data. |
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* @param Predict_QTH $qth The observer data. |
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* @param int $maxdt The maximum number of days to look ahead. |
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* |
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* @return Predict_Pass Pointer instance or NULL if no pass can be |
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* found. |
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*/ |
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public function get_next_pass(Predict_Sat $sat, Predict_QTH $qth, $maxdt) |
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{ |
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/* get the current time and call the get_pass function */ |
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$now = Predict_Time::get_current_daynum(); |
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return $this->get_pass($sat, $qth, $now, $maxdt); |
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} |
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/** Predict first pass after a certain time. |
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* |
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* @param Predict_Sat $sat The satellite data. |
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* @param Predict_QTH $qth The observer's location data. |
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* @param float $start Starting time. |
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* @param int $maxdt The maximum number of days to look ahead (0 for no limit). |
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* |
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* @return Predict_Pass or NULL if there was an error. |
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* |
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* This function will find the first upcoming pass with AOS no earlier than |
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* t = start and no later than t = (start+maxdt). |
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* |
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* note For no time limit use maxdt = 0.0 |
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* |
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* note the data in sat will be corrupt (future) and must be refreshed |
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* by the caller, if the caller will need it later on |
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*/ |
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public function get_pass(Predict_Sat $sat_in, Predict_QTH $qth, $start, $maxdt) |
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{ |
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$aos = 0.0; /* time of AOS */ |
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$tca = 0.0; /* time of TCA */ |
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$los = 0.0; /* time of LOS */ |
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$dt = 0.0; /* time diff */ |
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$step = 0.0; /* time step */ |
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$t0 = $start; |
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$tres = 0.0; /* required time resolution */ |
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$max_el = 0.0; /* maximum elevation */ |
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$pass = null; |
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$detail = null; |
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$done = false; |
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$iter = 0; /* number of iterations */ |
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/* FIXME: watchdog */ |
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/*copy sat_in to a working structure*/ |
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$sat = clone $sat_in; |
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$sat_working = clone $sat_in; |
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/* get time resolution; sat-cfg stores it in seconds */ |
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$tres = $this->timeRes / 86400.0; |
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/* loop until we find a pass with elevation > SAT_CFG_INT_PRED_MIN_EL |
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or we run out of time |
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FIXME: we should have a safety break |
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*/ |
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while (!$done) { |
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/* Find los of next pass or of current pass */ |
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$los = $this->find_los($sat, $qth, $t0, $maxdt); // See if a pass is ongoing |
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$aos = $this->find_aos($sat, $qth, $t0, $maxdt); |
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/* sat_log_log(SAT_LOG_LEVEL_MSG, "%s:%s:%d: found aos %f and los %f for t0=%f", */ |
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/* __FILE__, */ |
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/* __FUNCTION__, */ |
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/* __LINE__, */ |
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/* aos, */ |
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/* los, */ |
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/* t0); */ |
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if ($aos > $los) { |
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// los is from an currently happening pass, find previous aos |
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$aos = $this->find_prev_aos($sat, $qth, $t0); |
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} |
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/* aos = 0.0 means no aos */ |
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if ($aos == 0.0) { |
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$done = true; |
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} else if (($maxdt > 0.0) && ($aos > ($start + $maxdt)) ) { |
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/* check whether we are within time limits; |
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maxdt = 0 mean no time limit. |
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*/ |
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$done = true; |
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} else { |
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//los = find_los (sat, qth, aos + 0.001, maxdt); // +1.5 min later |
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$dt = $los - $aos; |
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/* get time step, which will give us the max number of entries */ |
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$step = $dt / $this->numEntries; |
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/* but if this is smaller than the required resolution |
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we go with the resolution |
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*/ |
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if ($step < $tres) { |
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$step = $tres; |
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} |
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/* create a pass_t entry; FIXME: g_try_new in 2.8 */ |
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$pass = new Predict_Pass(); |
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$pass->aos = $aos; |
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$pass->los = $los; |
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$pass->max_el = 0.0; |
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$pass->aos_az = 0.0; |
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$pass->los_az = 0.0; |
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$pass->maxel_az = 0.0; |
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$pass->vis = '---'; |
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$pass->satname = $sat->nickname; |
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$pass->details = array(); |
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/* iterate over each time step */ |
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for ($t = $pass->aos; $t <= $pass->los; $t += $step) { |
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/* calculate satellite data */ |
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$this->predict_calc($sat, $qth, $t); |
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/* in the first iter we want to store |
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pass->aos_az |
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*/ |
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if ($t == $pass->aos) { |
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$pass->aos_az = $sat->az; |
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$pass->orbit = $sat->orbit; |
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} |
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/* append details to sat->details */ |
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$detail = new Predict_PassDetail(); |
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$detail->time = $t; |
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$detail->pos->x = $sat->pos->x; |
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$detail->pos->y = $sat->pos->y; |
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$detail->pos->z = $sat->pos->z; |
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$detail->pos->w = $sat->pos->w; |
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$detail->vel->x = $sat->vel->x; |
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$detail->vel->y = $sat->vel->y; |
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$detail->vel->z = $sat->vel->z; |
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$detail->vel->w = $sat->vel->w; |
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$detail->velo = $sat->velo; |
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$detail->az = $sat->az; |
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$detail->el = $sat->el; |
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$detail->range = $sat->range; |
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$detail->range_rate = $sat->range_rate; |
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$detail->lat = $sat->ssplat; |
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$detail->lon = $sat->ssplon; |
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$detail->alt = $sat->alt; |
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$detail->ma = $sat->ma; |
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$detail->phase = $sat->phase; |
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$detail->footprint = $sat->footprint; |
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$detail->orbit = $sat->orbit; |
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$detail->vis = $this->get_sat_vis($sat, $qth, $t); |
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/* also store visibility "bit" */ |
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switch ($detail->vis) { |
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case self::SAT_VIS_VISIBLE: |
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$pass->vis[0] = 'V'; |
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break; |
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case self::SAT_VIS_DAYLIGHT: |
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$pass->vis[1] = 'D'; |
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break; |
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case self::SAT_VIS_ECLIPSED: |
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$pass->vis[2] = 'E'; |
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break; |
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default: |
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break; |
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} |
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// Using an array, no need to prepend and reverse the list |
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// as gpredict does |
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$pass->details[] = $detail; |
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// Look up apparent magnitude if this is a visible pass |
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if ($detail->vis === self::SAT_VIS_VISIBLE) { |
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$apmag = $sat->calculateApparentMagnitude($t, $qth); |
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if ($pass->max_apparent_magnitude === null || $apmag < $pass->max_apparent_magnitude) { |
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$pass->max_apparent_magnitude = $apmag; |
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} |
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} |
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/* store elevation if greater than the |
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previously stored one |
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*/ |
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if ($sat->el > $max_el) { |
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$max_el = $sat->el; |
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$tca = $t; |
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$pass->maxel_az = $sat->az; |
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} |
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/* g_print ("TIME: %f\tAZ: %f\tEL: %f (MAX: %f)\n", */ |
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/* t, sat->az, sat->el, max_el); */ |
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} |
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/* calculate satellite data */ |
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$this->predict_calc($sat, $qth, $pass->los); |
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/* store los_az, max_el and tca */ |
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$pass->los_az = $sat->az; |
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$pass->max_el = $max_el; |
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$pass->tca = $tca; |
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|
/* check whether this pass is good */ |
329
|
|
|
if ($max_el >= $this->minEle) { |
330
|
|
|
$done = true; |
331
|
|
|
} else { |
332
|
|
|
$done = false; |
333
|
|
|
$t0 = $los + 0.014; // +20 min |
334
|
|
|
$pass = null; |
335
|
|
|
} |
336
|
|
|
|
337
|
|
|
$iter++; |
338
|
|
|
} |
339
|
|
|
} |
340
|
|
|
|
341
|
|
|
return $pass; |
342
|
|
|
} |
343
|
|
|
|
344
|
|
|
/** |
345
|
|
|
* Calculate satellite visibility. |
346
|
|
|
* |
347
|
|
|
* @param Predict_Sat $sat The satellite structure. |
348
|
|
|
* @param Predict_QTH $qth The QTH |
349
|
|
|
* @param float $jul_utc The time at which the visibility should be calculated. |
350
|
|
|
* |
351
|
|
|
* @return int The visiblity constant, 0, 1, 2, or 3 (see above) |
352
|
|
|
*/ |
353
|
|
|
public function get_sat_vis(Predict_Sat $sat, Predict_QTH $qth, $jul_utc) |
354
|
|
|
{ |
355
|
|
|
/* gboolean sat_sun_status; |
356
|
|
|
gdouble sun_el; |
357
|
|
|
gdouble threshold; |
358
|
|
|
gdouble eclipse_depth; |
359
|
|
|
sat_vis_t vis = SAT_VIS_NONE; */ |
360
|
|
|
|
361
|
|
|
$eclipse_depth = 0.0; |
362
|
|
|
$zero_vector = new Predict_Vector(); |
363
|
|
|
$obs_geodetic = new Predict_Geodetic(); |
364
|
|
|
|
365
|
|
|
/* Solar ECI position vector */ |
366
|
|
|
$solar_vector = new Predict_Vector(); |
367
|
|
|
|
368
|
|
|
/* Solar observed az and el vector */ |
369
|
|
|
$solar_set = new Predict_ObsSet(); |
370
|
|
|
|
371
|
|
|
/* FIXME: could be passed as parameter */ |
372
|
|
|
$obs_geodetic->lon = $qth->lon * self::de2ra; |
373
|
|
|
$obs_geodetic->lat = $qth->lat * self::de2ra; |
374
|
|
|
$obs_geodetic->alt = $qth->alt / 1000.0; |
375
|
|
|
$obs_geodetic->theta = 0; |
376
|
|
|
|
377
|
|
|
Predict_Solar::Calculate_Solar_Position($jul_utc, $solar_vector); |
378
|
|
|
Predict_SGPObs::Calculate_Obs($jul_utc, $solar_vector, $zero_vector, $obs_geodetic, $solar_set); |
379
|
|
|
|
380
|
|
|
if (Predict_Solar::Sat_Eclipsed($sat->pos, $solar_vector, $eclipse_depth)) { |
381
|
|
|
/* satellite is eclipsed */ |
382
|
|
|
$sat_sun_status = false; |
383
|
|
|
} else { |
384
|
|
|
/* satellite in sunlight => may be visible */ |
385
|
|
|
$sat_sun_status = true; |
386
|
|
|
} |
387
|
|
|
|
388
|
|
|
if ($sat_sun_status) { |
389
|
|
|
$sun_el = Predict_Math::Degrees($solar_set->el); |
390
|
|
|
|
391
|
|
|
if ($sun_el <= $this->threshold && $sat->el >= 0.0) { |
392
|
|
|
$vis = self::SAT_VIS_VISIBLE; |
393
|
|
|
} else { |
394
|
|
|
$vis = self::SAT_VIS_DAYLIGHT; |
395
|
|
|
} |
396
|
|
|
} else { |
397
|
|
|
$vis = self::SAT_VIS_ECLIPSED; |
398
|
|
|
} |
399
|
|
|
|
400
|
|
|
return $vis; |
401
|
|
|
} |
402
|
|
|
|
403
|
|
|
/** Find the AOS time of the next pass. |
404
|
|
|
* @author Alexandru Csete, OZ9AEC |
405
|
|
|
* @author John A. Magliacane, KD2BD |
406
|
|
|
* @param Predict_Sat $sat The satellite data. |
407
|
|
|
* @param Predict_QTH $qth The observer's location (QTH) data. |
408
|
|
|
* @param float $start The julian date where calculation should start. |
409
|
|
|
* @param int $maxdt The upper time limit in days (0.0 = no limit) |
410
|
|
|
* @return The julain date of the next AOS or 0.0 if the satellite has no AOS. |
411
|
|
|
* |
412
|
|
|
* This function finds the time of AOS for the first coming pass taking place |
413
|
|
|
* no earlier that start. |
414
|
|
|
* If the satellite is currently within range, the function first calls |
415
|
|
|
* find_los to get the next LOS time. Then the calculations are done using |
416
|
|
|
* the new start time. |
417
|
|
|
* |
418
|
|
|
*/ |
419
|
|
|
public function find_aos(Predict_Sat $sat, Predict_QTH $qth, $start, $maxdt) |
420
|
|
|
{ |
421
|
|
|
$t = $start; |
422
|
|
|
$aostime = 0.0; |
423
|
|
|
|
424
|
|
|
|
425
|
|
|
/* make sure current sat values are |
426
|
|
|
in sync with the time |
427
|
|
|
*/ |
428
|
|
|
$this->predict_calc($sat, $qth, $start); |
429
|
|
|
|
430
|
|
|
/* check whether satellite has aos */ |
431
|
|
|
if (($sat->otype == Predict_SGPSDP::ORBIT_TYPE_GEO) || |
432
|
|
|
($sat->otype == Predict_SGPSDP::ORBIT_TYPE_DECAYED) || |
433
|
|
|
!$this->has_aos($sat, $qth)) { |
434
|
|
|
|
435
|
|
|
return 0.0; |
436
|
|
|
} |
437
|
|
|
|
438
|
|
|
if ($sat->el > 0.0) { |
439
|
|
|
$t = $this->find_los($sat, $qth, $start, $maxdt) + 0.014; // +20 min |
440
|
|
|
} |
441
|
|
|
|
442
|
|
|
/* invalid time (potentially returned by find_los) */ |
443
|
|
|
if ($t < 0.1) { |
444
|
|
|
return 0.0; |
445
|
|
|
} |
446
|
|
|
|
447
|
|
|
/* update satellite data */ |
448
|
|
|
$this->predict_calc($sat, $qth, $t); |
449
|
|
|
|
450
|
|
|
/* use upper time limit */ |
451
|
|
|
if ($maxdt > 0.0) { |
452
|
|
|
|
453
|
|
|
/* coarse time steps */ |
454
|
|
|
while (($sat->el < -1.0) && ($t <= ($start + $maxdt))) { |
455
|
|
|
$t -= 0.00035 * ($sat->el * (($sat->alt / 8400.0) + 0.46) - 2.0); |
456
|
|
|
$this->predict_calc($sat, $qth, $t); |
457
|
|
|
} |
458
|
|
|
|
459
|
|
|
/* fine steps */ |
460
|
|
|
while (($aostime == 0.0) && ($t <= ($start + $maxdt))) { |
461
|
|
|
|
462
|
|
|
if (abs($sat->el) < 0.005) { |
463
|
|
|
$aostime = $t; |
464
|
|
|
} else { |
465
|
|
|
$t -= $sat->el * sqrt($sat->alt) / 530000.0; |
466
|
|
|
$this->predict_calc($sat, $qth, $t); |
467
|
|
|
} |
468
|
|
|
} |
469
|
|
|
} else { |
470
|
|
|
/* don't use upper time limit */ |
471
|
|
|
|
472
|
|
|
/* coarse time steps */ |
473
|
|
|
while ($sat->el < -1.0) { |
474
|
|
|
|
475
|
|
|
$t -= 0.00035 * ($sat->el * (($sat->alt / 8400.0) + 0.46) - 2.0); |
476
|
|
|
$this->predict_calc($sat, $qth, $t); |
477
|
|
|
} |
478
|
|
|
|
479
|
|
|
/* fine steps */ |
480
|
|
|
while ($aostime == 0.0) { |
481
|
|
|
|
482
|
|
|
if (abs($sat->el) < 0.005) { |
483
|
|
|
$aostime = $t; |
484
|
|
|
} else { |
485
|
|
|
$t -= $sat->el * sqrt($sat->alt) / 530000.0; |
486
|
|
|
$this->predict_calc($sat, $qth, $t); |
487
|
|
|
} |
488
|
|
|
|
489
|
|
|
} |
490
|
|
|
} |
491
|
|
|
|
492
|
|
|
return $aostime; |
493
|
|
|
} |
494
|
|
|
|
495
|
|
|
/** SGP4SDP4 driver for doing AOS/LOS calculations. |
496
|
|
|
* @param Predict_Sat $sat The satellite data. |
497
|
|
|
* @param Predict_QTH $qth The QTH observer location data. |
498
|
|
|
* @param float $t The time for calculation (Julian Date) |
499
|
|
|
* |
500
|
|
|
*/ |
501
|
|
|
public function predict_calc(Predict_Sat $sat, Predict_QTH $qth, $t) |
502
|
|
|
{ |
503
|
|
|
$obs_set = new Predict_ObsSet(); |
504
|
|
|
$sat_geodetic = new Predict_Geodetic(); |
505
|
|
|
$obs_geodetic = new Predict_Geodetic(); |
506
|
|
|
|
507
|
|
|
$obs_geodetic->lon = $qth->lon * self::de2ra; |
508
|
|
|
$obs_geodetic->lat = $qth->lat * self::de2ra; |
509
|
|
|
$obs_geodetic->alt = $qth->alt / 1000.0; |
510
|
|
|
$obs_geodetic->theta = 0; |
511
|
|
|
|
512
|
|
|
$sat->jul_utc = $t; |
513
|
|
|
$sat->tsince = ($sat->jul_utc - $sat->jul_epoch) * self::xmnpda; |
514
|
|
|
|
515
|
|
|
/* call the norad routines according to the deep-space flag */ |
516
|
|
|
$sgpsdp = Predict_SGPSDP::getInstance($sat); |
517
|
|
|
if ($sat->flags & Predict_SGPSDP::DEEP_SPACE_EPHEM_FLAG) { |
518
|
|
|
$sgpsdp->SDP4($sat, $sat->tsince); |
519
|
|
|
} else { |
520
|
|
|
$sgpsdp->SGP4($sat, $sat->tsince); |
521
|
|
|
} |
522
|
|
|
|
523
|
|
|
Predict_Math::Convert_Sat_State($sat->pos, $sat->vel); |
524
|
|
|
|
525
|
|
|
/* get the velocity of the satellite */ |
526
|
|
|
$sat->vel->w = sqrt($sat->vel->x * $sat->vel->x + $sat->vel->y * $sat->vel->y + $sat->vel->z * $sat->vel->z); |
|
|
|
|
527
|
|
|
$sat->velo = $sat->vel->w; |
528
|
|
|
Predict_SGPObs::Calculate_Obs($sat->jul_utc, $sat->pos, $sat->vel, $obs_geodetic, $obs_set); |
529
|
|
|
Predict_SGPObs::Calculate_LatLonAlt($sat->jul_utc, $sat->pos, $sat_geodetic); |
530
|
|
|
|
531
|
|
|
while ($sat_geodetic->lon < -self::pi) { |
532
|
|
|
$sat_geodetic->lon += self::twopi; |
533
|
|
|
} |
534
|
|
|
|
535
|
|
|
while ($sat_geodetic->lon > (self::pi)) { |
536
|
|
|
$sat_geodetic->lon -= self::twopi; |
537
|
|
|
} |
538
|
|
|
|
539
|
|
|
$sat->az = Predict_Math::Degrees($obs_set->az); |
540
|
|
|
$sat->el = Predict_Math::Degrees($obs_set->el); |
541
|
|
|
$sat->range = $obs_set->range; |
542
|
|
|
$sat->range_rate = $obs_set->range_rate; |
543
|
|
|
$sat->ssplat = Predict_Math::Degrees($sat_geodetic->lat); |
544
|
|
|
$sat->ssplon = Predict_Math::Degrees($sat_geodetic->lon); |
545
|
|
|
$sat->alt = $sat_geodetic->alt; |
546
|
|
|
$sat->ma = Predict_Math::Degrees($sat->phase); |
547
|
|
|
$sat->ma *= 256.0 / 360.0; |
548
|
|
|
$sat->phase = Predict_Math::Degrees($sat->phase); |
549
|
|
|
|
550
|
|
|
/* same formulas, but the one from predict is nicer */ |
551
|
|
|
//sat->footprint = 2.0 * xkmper * acos (xkmper/sat->pos.w); |
552
|
|
|
$sat->footprint = 12756.33 * acos(self::xkmper / (self::xkmper + $sat->alt)); |
553
|
|
|
$age = $sat->jul_utc - $sat->jul_epoch; |
554
|
|
|
$sat->orbit = floor(($sat->tle->xno * self::xmnpda / self::twopi + |
555
|
|
|
$age * $sat->tle->bstar * self::ae) * $age + |
556
|
|
|
$sat->tle->xmo / self::twopi) + $sat->tle->revnum - 1; |
557
|
|
|
} |
558
|
|
|
|
559
|
|
|
/** Find the LOS time of the next pass. |
560
|
|
|
* @author Alexandru Csete, OZ9AEC |
561
|
|
|
* @author John A. Magliacane, KD2BD |
562
|
|
|
* @param Predict_Sat $sat The satellite data. |
563
|
|
|
* @param Predict_QTH $qth The QTH observer location data. |
564
|
|
|
* @param float $start The time where calculation should start. (Julian Date) |
565
|
|
|
* @param int $maxdt The upper time limit in days (0.0 = no limit) |
566
|
|
|
* @return The time (julian date) of the next LOS or 0.0 if the satellite has no LOS. |
567
|
|
|
* |
568
|
|
|
* This function finds the time of LOS for the first coming pass taking place |
569
|
|
|
* no earlier that start. |
570
|
|
|
* If the satellite is currently out of range, the function first calls |
571
|
|
|
* find_aos to get the next AOS time. Then the calculations are done using |
572
|
|
|
* the new start time. |
573
|
|
|
* The function has a built-in watchdog to ensure that we don't end up in |
574
|
|
|
* lengthy loops. |
575
|
|
|
* |
576
|
|
|
*/ |
577
|
|
|
public function find_los(Predict_Sat $sat, Predict_QTH $qth, $start, $maxdt) |
578
|
|
|
{ |
579
|
|
|
$t = $start; |
580
|
|
|
$lostime = 0.0; |
581
|
|
|
|
582
|
|
|
|
583
|
|
|
$this->predict_calc($sat, $qth, $start); |
584
|
|
|
|
585
|
|
|
/* check whether satellite has aos */ |
586
|
|
|
if (($sat->otype == Predict_SGPSDP::ORBIT_TYPE_GEO) || |
587
|
|
|
($sat->otype == Predict_SGPSDP::ORBIT_TYPE_DECAYED) || |
588
|
|
|
!$this->has_aos ($sat, $qth)) { |
589
|
|
|
|
590
|
|
|
return 0.0; |
591
|
|
|
} |
592
|
|
|
|
593
|
|
|
if ($sat->el < 0.0) { |
594
|
|
|
$t = $this->find_aos($sat, $qth, $start, $maxdt) + 0.001; // +1.5 min |
595
|
|
|
} |
596
|
|
|
|
597
|
|
|
/* invalid time (potentially returned by find_aos) */ |
598
|
|
|
if ($t < 0.01) { |
599
|
|
|
return 0.0; |
600
|
|
|
} |
601
|
|
|
|
602
|
|
|
/* update satellite data */ |
603
|
|
|
$this->predict_calc($sat, $qth, $t); |
604
|
|
|
|
605
|
|
|
/* use upper time limit */ |
606
|
|
|
if ($maxdt > 0.0) { |
607
|
|
|
|
608
|
|
|
/* coarse steps */ |
609
|
|
|
while (($sat->el >= 1.0) && ($t <= ($start + $maxdt))) { |
610
|
|
|
$t += cos(($sat->el - 1.0) * self::de2ra) * sqrt($sat->alt) / 25000.0; |
611
|
|
|
$this->predict_calc($sat, $qth, $t); |
612
|
|
|
} |
613
|
|
|
|
614
|
|
|
/* fine steps */ |
615
|
|
|
while (($lostime == 0.0) && ($t <= ($start + $maxdt))) { |
616
|
|
|
|
617
|
|
|
$t += $sat->el * sqrt($sat->alt) / 502500.0; |
618
|
|
|
$this->predict_calc($sat, $qth, $t); |
619
|
|
|
|
620
|
|
|
if (abs($sat->el) < 0.005) { |
621
|
|
|
$lostime = $t; |
622
|
|
|
} |
623
|
|
|
} |
624
|
|
|
} else { |
625
|
|
|
/* don't use upper limit */ |
626
|
|
|
|
627
|
|
|
/* coarse steps */ |
628
|
|
|
while ($sat->el >= 1.0) { |
629
|
|
|
$t += cos(($sat->el - 1.0) * self::de2ra) * sqrt($sat->alt) / 25000.0; |
630
|
|
|
$this->predict_calc($sat, $qth, $t); |
631
|
|
|
} |
632
|
|
|
|
633
|
|
|
/* fine steps */ |
634
|
|
|
while ($lostime == 0.0) { |
635
|
|
|
|
636
|
|
|
$t += $sat->el * sqrt($sat->alt) / 502500.0; |
637
|
|
|
$this->predict_calc($sat, $qth, $t); |
638
|
|
|
|
639
|
|
|
if (abs($sat->el) < 0.005) |
640
|
|
|
$lostime = $t; |
641
|
|
|
} |
642
|
|
|
} |
643
|
|
|
|
644
|
|
|
return $lostime; |
645
|
|
|
} |
646
|
|
|
|
647
|
|
|
/** Find AOS time of current pass. |
648
|
|
|
* @param Predict_Sat $sat The satellite to find AOS for. |
649
|
|
|
* @param Predict_QTH $qth The ground station. |
650
|
|
|
* @param float $start Start time, prefereably now. |
651
|
|
|
* @return The time of the previous AOS or 0.0 if the satellite has no AOS. |
652
|
|
|
* |
653
|
|
|
* This function can be used to find the AOS time in the past of the |
654
|
|
|
* current pass. |
655
|
|
|
*/ |
656
|
|
|
public function find_prev_aos(Predict_Sat $sat, Predict_QTH $qth, $start) |
657
|
|
|
{ |
658
|
|
|
$aostime = $start; |
659
|
|
|
|
660
|
|
|
/* make sure current sat values are |
661
|
|
|
in sync with the time |
662
|
|
|
*/ |
663
|
|
|
$this->predict_calc($sat, $qth, $start); |
664
|
|
|
|
665
|
|
|
/* check whether satellite has aos */ |
666
|
|
|
if (($sat->otype == Predict_SGPSDP::ORBIT_TYPE_GEO) || |
667
|
|
|
($sat->otype == Predict_SGPSDP::ORBIT_TYPE_DECAYED) || |
668
|
|
|
!$this->has_aos($sat, $qth)) { |
669
|
|
|
|
670
|
|
|
return 0.0; |
671
|
|
|
} |
672
|
|
|
|
673
|
|
|
while ($sat->el >= 0.0) { |
674
|
|
|
$aostime -= 0.0005; // 0.75 min |
675
|
|
|
$this->predict_calc($sat, $qth, $aostime); |
676
|
|
|
} |
677
|
|
|
|
678
|
|
|
return $aostime; |
679
|
|
|
} |
680
|
|
|
|
681
|
|
|
/** Determine whether satellite ever reaches AOS. |
682
|
|
|
* @author John A. Magliacane, KD2BD |
683
|
|
|
* @author Alexandru Csete, OZ9AEC |
684
|
|
|
* @param Predict_Sat $sat The satellite data. |
685
|
|
|
* @param Predict_QTH $qth The observer's location data |
686
|
|
|
* @return bool true if the satellite will reach AOS, false otherwise. |
687
|
|
|
* |
688
|
|
|
*/ |
689
|
|
|
public function has_aos(Predict_Sat $sat, Predict_QTH $qth) |
690
|
|
|
{ |
691
|
|
|
$retcode = false; |
|
|
|
|
692
|
|
|
|
693
|
|
|
/* FIXME */ |
694
|
|
|
if ($sat->meanmo == 0.0) { |
695
|
|
|
$retcode = false; |
696
|
|
|
} else { |
697
|
|
|
|
698
|
|
|
/* xincl is already in RAD by select_ephemeris */ |
699
|
|
|
$lin = $sat->tle->xincl; |
700
|
|
|
if ($lin >= self::pio2) { |
701
|
|
|
$lin = self::pi - $lin; |
702
|
|
|
} |
703
|
|
|
|
704
|
|
|
$sma = 331.25 * exp(log(1440.0 / $sat->meanmo) * (2.0 / 3.0)); |
705
|
|
|
$apogee = $sma * (1.0 + $sat->tle->eo) - self::xkmper; |
706
|
|
|
|
707
|
|
|
if ((acos(self::xkmper / ($apogee + self::xkmper)) + ($lin)) > abs($qth->lat * self::de2ra)) { |
708
|
|
|
$retcode = true; |
709
|
|
|
} else { |
710
|
|
|
$retcode = false; |
711
|
|
|
} |
712
|
|
|
} |
713
|
|
|
|
714
|
|
|
return $retcode; |
715
|
|
|
} |
716
|
|
|
|
717
|
|
|
/** Predict passes after a certain time. |
718
|
|
|
* |
719
|
|
|
* |
720
|
|
|
* This function calculates num upcoming passes with AOS no earlier |
721
|
|
|
* than t = start and not later that t = (start+maxdt). The function will |
722
|
|
|
* repeatedly call get_pass until |
723
|
|
|
* the number of predicted passes is equal to num, the time has reached |
724
|
|
|
* limit or the get_pass function returns NULL. |
725
|
|
|
* |
726
|
|
|
* note For no time limit use maxdt = 0.0 |
727
|
|
|
* |
728
|
|
|
* note the data in sat will be corrupt (future) and must be refreshed |
729
|
|
|
* by the caller, if the caller will need it later on (eg. if the caller |
730
|
|
|
* is GtkSatList). |
731
|
|
|
* |
732
|
|
|
* note Prepending to a singly linked list is much faster than appending. |
733
|
|
|
* Therefore, the elements are prepended whereafter the GSList is |
734
|
|
|
* reversed |
735
|
|
|
* |
736
|
|
|
* |
737
|
|
|
* @param Predict_Sat $sat The satellite data |
738
|
|
|
* @param Predict_QTH $qth The observer's location data |
739
|
|
|
* @param float $start The start julian date |
740
|
|
|
* @param int $maxdt The max # of days to look |
741
|
|
|
* @param int $num The max # of passes to get |
742
|
|
|
* @return array of Predict_Pass instances if found, empty array otherwise |
743
|
|
|
*/ |
744
|
|
|
public function get_passes(Predict_Sat $sat, Predict_QTH $qth, $start, $maxdt, $num = 0) |
745
|
|
|
{ |
746
|
|
|
$passes = array(); |
747
|
|
|
|
748
|
|
|
/* if no number has been specified |
749
|
|
|
set it to something big */ |
750
|
|
|
if ($num == 0) { |
751
|
|
|
$num = 100; |
752
|
|
|
} |
753
|
|
|
|
754
|
|
|
$t = $start; |
755
|
|
|
|
756
|
|
|
for ($i = 0; $i < $num; $i++) { |
757
|
|
|
$pass = $this->get_pass($sat, $qth, $t, $maxdt); |
758
|
|
|
|
759
|
|
|
if ($pass != null) { |
760
|
|
|
$passes[] = $pass; |
761
|
|
|
$t = $pass->los + 0.014; // +20 min |
762
|
|
|
|
763
|
|
|
/* if maxdt > 0.0 check whether we have reached t = start+maxdt |
764
|
|
|
if yes finish predictions |
765
|
|
|
*/ |
766
|
|
|
if (($maxdt > 0.0) && ($t >= ($start + $maxdt))) { |
767
|
|
|
$i = $num; |
768
|
|
|
} |
769
|
|
|
} else { |
770
|
|
|
/* we can't get any more passes */ |
771
|
|
|
$i = $num; |
772
|
|
|
} |
773
|
|
|
} |
774
|
|
|
|
775
|
|
|
return $passes; |
776
|
|
|
} |
777
|
|
|
|
778
|
|
|
/** |
779
|
|
|
* Filters out visible passes and adds the visible aos, tca, los, and |
780
|
|
|
* corresponding az and ele for each. |
781
|
|
|
* |
782
|
|
|
* @param array $passes The passes returned from get_passes() |
783
|
|
|
* |
784
|
|
|
* @author Bill Shupp |
785
|
|
|
* @return array |
786
|
|
|
*/ |
787
|
|
|
public function filterVisiblePasses(array $passes) |
788
|
|
|
{ |
789
|
|
|
$filtered = array(); |
790
|
|
|
|
791
|
|
|
foreach ($passes as $result) { |
792
|
|
|
// Dummy check |
793
|
|
|
if ($result->vis[0] != 'V') { |
794
|
|
|
continue; |
795
|
|
|
} |
796
|
|
|
|
797
|
|
|
$aos = false; |
|
|
|
|
798
|
|
|
$aos_az = false; |
799
|
|
|
$aos = false; |
800
|
|
|
$tca = false; |
801
|
|
|
$los_az = false; |
802
|
|
|
$max_el = 0; |
803
|
|
|
|
804
|
|
|
foreach ($result->details as $detail) { |
805
|
|
|
if ($detail->vis != Predict::SAT_VIS_VISIBLE) { |
806
|
|
|
continue; |
807
|
|
|
} |
808
|
|
|
if ($detail->el < $this->minEle) { |
809
|
|
|
continue; |
810
|
|
|
} |
811
|
|
|
|
812
|
|
|
if ($aos == false) { |
813
|
|
|
$aos = $detail->time; |
814
|
|
|
$aos_az = $detail->az; |
815
|
|
|
$aos_el = $detail->el; |
816
|
|
|
$tca = $detail->time; |
817
|
|
|
$los = $detail->time; |
818
|
|
|
$los_az = $detail->az; |
819
|
|
|
$los_el = $detail->el; |
820
|
|
|
$max_el = $detail->el; |
821
|
|
|
$max_el_az = $detail->el; |
822
|
|
|
continue; |
823
|
|
|
} |
824
|
|
|
$los = $detail->time; |
825
|
|
|
$los_az = $detail->az; |
826
|
|
|
$los_el = $detail->el; |
827
|
|
|
|
828
|
|
|
if ($detail->el > $max_el) { |
829
|
|
|
$tca = $detail->time; |
830
|
|
|
$max_el = $detail->el; |
831
|
|
|
$max_el_az = $detail->az; |
832
|
|
|
} |
833
|
|
|
} |
834
|
|
|
|
835
|
|
|
if ($aos === false) { |
836
|
|
|
// Does not reach minimum elevation, skip |
837
|
|
|
continue; |
838
|
|
|
} |
839
|
|
|
|
840
|
|
|
$result->visible_aos = $aos; |
841
|
|
|
$result->visible_aos_az = $aos_az; |
842
|
|
|
$result->visible_aos_el = $aos_el; |
|
|
|
|
843
|
|
|
$result->visible_tca = $tca; |
844
|
|
|
$result->visible_max_el = $max_el; |
845
|
|
|
$result->visible_max_el_az = $max_el_az; |
|
|
|
|
846
|
|
|
$result->visible_los = $los; |
|
|
|
|
847
|
|
|
$result->visible_los_az = $los_az; |
848
|
|
|
$result->visible_los_el = $los_el; |
|
|
|
|
849
|
|
|
|
850
|
|
|
$filtered[] = $result; |
851
|
|
|
} |
852
|
|
|
|
853
|
|
|
return $filtered; |
854
|
|
|
} |
855
|
|
|
|
856
|
|
|
/** |
857
|
|
|
* Translates aziumuth degrees to compass direction: |
858
|
|
|
* |
859
|
|
|
* N (0°), NNE (22.5°), NE (45°), ENE (67.5°), E (90°), ESE (112.5°), |
860
|
|
|
* SE (135°), SSE (157.5°), S (180°), SSW (202.5°), SW (225°), |
861
|
|
|
* WSW (247.5°), W (270°), WNW (292.5°), NW (315°), NNW (337.5°) |
862
|
|
|
* |
863
|
|
|
* @param int $az The azimuth in degrees, defaults to 0 |
864
|
|
|
* |
865
|
|
|
* @return string |
866
|
|
|
*/ |
867
|
|
|
public function azDegreesToDirection($az = 0) |
868
|
|
|
{ |
869
|
|
|
$i = floor($az / 22.5); |
870
|
|
|
$m = (22.5 * (2 * $i + 1)) / 2; |
871
|
|
|
$i = ($az >= $m) ? $i + 1 : $i; |
872
|
|
|
|
873
|
|
|
return trim(substr('N NNENE ENEE ESESE SSES SSWSW WSWW WNWNW NNWN ', $i * 3, 3)); |
874
|
|
|
} |
875
|
|
|
} |
876
|
|
|
|
This check looks for PHPDoc comments describing methods or function parameters that do not exist on the corresponding method or function.
Consider the following example. The parameter
$italy
is not defined by the methodfinale(...)
.The most likely cause is that the parameter was removed, but the annotation was not.