src/ATC/approach.cxx

   1 // FGApproach - a class to provide approach control at larger airports.
   2 //
   3 // Written by Alexander Kappes, started March 2002.
   4 //
   5 // Copyright (C) 2002  Alexander Kappes
   6 //
   7 // This program is free software; you can redistribute it and/or
   8 // modify it under the terms of the GNU General Public License as
   9 // published by the Free Software Foundation; either version 2 of the
  10 // License, or (at your option) any later version.
  11 //
  12 // This program is distributed in the hope that it will be useful, but
  13 // WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15 // General Public License for more details.
  16 //
  17 // You should have received a copy of the GNU General Public License
  18 // along with this program; if not, write to the Free Software
  19 // Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20
  21 #include "approach.hxx"
  22 #include "transmission.hxx"
  23 #include "transmissionlist.hxx"
  24 #include "ATCdisplay.hxx"
  25 #include "ATCDialog.hxx"
  26
  27 #include <Airports/runways.hxx>
  28 #include <simgear/math/polar3d.hxx>
  29 #include <simgear/misc/sg_path.hxx>
  30
  31 #include <Environment/environment_mgr.hxx>
  32 #include <Environment/environment.hxx>
  33
  34
  35 #include <GUI/gui.h>
  36
  37 //Constructor
  38 FGApproach::FGApproach(){
  39   comm1_node = fgGetNode("/instrumentation/comm[0]/frequencies/selected-mhz", true);
  40   comm2_node = fgGetNode("/instrumentation/comm[1]/frequencies/selected-mhz", true);
  41
  42   _type = APPROACH;
  43
  44   num_planes = 0;
  45   lon_node   = fgGetNode("/position/longitude-deg", true);
  46   lat_node   = fgGetNode("/position/latitude-deg", true);
  47   elev_node  = fgGetNode("/position/altitude-ft", true);
  48   hdg_node   = fgGetNode("/orientation/heading-deg", true);
  49   speed_node = fgGetNode("/velocities/airspeed-kt", true);
  50   etime_node = fgGetNode("/sim/time/elapsed-sec", true);
  51
  52   first = true;
  53   active_runway = "";
  54   int i;
  55   for ( i=0; i<max_planes; i++) {
  56     planes[i].contact   = 0;
  57     planes[i].wpn       = 0;
  58     planes[i].dnwp      = -999.;
  59     planes[i].on_crs    = true;
  60     planes[i].turn_rate = 10.0;
  61     planes[i].desc_rate = 1000.0;
  62     planes[i].clmb_rate = 500.0;
  63     planes[i].tlm       = 0.0;
  64     planes[i].lmc.c1    = 0;
  65     planes[i].lmc.c2    = 0;
  66     planes[i].lmc.c3    = -1;
  67     planes[i].wp_change = false;
  68   }
  69 }
  70
  71 //Destructor
  72 FGApproach::~FGApproach(){
  73 }
  74
  75 void FGApproach::Init() {
  76 }
  77
  78
  79
  80 // ============================================================================
  81 // the main update function
  82 // ============================================================================
  83 void FGApproach::Update(double dt) {
  84
  85         const int max_trans = 20;
  86         FGTransmission tmissions[max_trans];
  87         int    wpn;
  88         atc_type station = APPROACH;
  89         TransCode code;
  90         TransPar TPar;
  91         int    i,j;
  92         //double course, d,
  93         double adif, datp;
  94         //char   buf[10];
  95         string message;
  96         //static string atcmsg1[10];
  97         //static string atcmsg2[10];
  98         string mentry;
  99         string transm;
 100         TransPar tpars;
 101         //static bool TransDisplayed = false;
 102
 103         update_plane_dat();
 104         if ( active_runway == "" ) get_active_runway();
 105
 106         double comm1_freq = comm1_node->getDoubleValue();
 107
 108         //bool DisplayTransmissions = true;
 109
 110         for (i=0; i<num_planes; i++) {
 111                 if ( planes[i].ident == "Player") {
 112                         station = APPROACH;
 113                         tpars.station = name;
 114                         tpars.callsign = "Player";
 115                         tpars.airport = ident;
 116
 117                         //cout << "ident = " << ident << " name = " << name << '\n';
 118
 119                         int num_trans = 0;
 120                         // is the frequency of the station tuned in?
 121                         if ( freq == (int)(comm1_freq*100.0 + 0.5) ) {
 122                                 current_transmissionlist->query_station( station, tmissions, max_trans, num_trans );
 123                                 // loop over all transmissions for station
 124                                 for ( j=0; j<=num_trans-1; j++ ) {
 125                                         code = tmissions[j].get_code();
 126                                         //cout << "code is " << code.c1 << "  " << code.c2 << "  " << code.c3 << '\n';
 127                                         // select proper transmissions
 128                                         if(code.c3 != 2) {    // DCL - hack to prevent request crossing airspace being displayed since this isn't implemented yet.
 129                                             if ( ( code.c2 == -1 && planes[i].lmc.c3 == 0 ) ||
 130                                                     ( code.c1 == 0  && code.c2 == planes[i].lmc.c2 ) ) {
 131                                                     mentry = current_transmissionlist->gen_text(station, code, tpars, false);
 132                                                     transm = current_transmissionlist->gen_text(station, code, tpars, true);
 133                                                     // is the transmission already registered?
 134                                                     if (!current_atcdialog->trans_reg( ident, transm, APPROACH )) {
 135                                                             current_atcdialog->add_entry( ident, transm, mentry, APPROACH, 0 );
 136                                                     }
 137                                             }
 138                                         }
 139                                 }
 140                         }
 141                 }
 142         }
 143
 144         for ( i=0; i<num_planes; i++ ) {
 145                 //cout << "TPar.airport = " << TPar.airport << " TPar.station = " << TPar.station << " TPar.callsign = " << TPar.callsign << '\n';
 146                 //if ( planes[i].ident == TPar.callsign && name == TPar.airport && TPar.station == "approach" ) {
 147                         //if ( TPar.request && TPar.intention == "landing" && ident == TPar.intid) {
 148                         if(planes[i].ident == "Player" && fgGetBool("/sim/atc/opt0")) {
 149                                 //cout << "Landing requested\n";
 150                                 fgSetBool("/sim/atc/opt0", false);
 151                                 planes[i].wpn = 0;
 152                                 // ===========================
 153                                 // === calculate waypoints ===
 154                                 // ===========================
 155                                 calc_wp( i );
 156                                 update_param( i );
 157                                 wpn = planes[i].wpn-1;
 158                                 planes[i].aalt = planes[i].wpts[wpn-1][2];
 159                                 planes[i].ahdg = planes[i].wpts[wpn][4];
 160
 161                                 // generate the message
 162                                 code.c1 = 1;
 163                                 code.c2 = 1;
 164                                 code.c3 = 0;
 165                                 adif = angle_diff_deg( planes[i].hdg, planes[i].ahdg );
 166                                 tpars.station = name;
 167                                 tpars.callsign = "Player";
 168                                 if ( adif < 0 ) tpars.tdir = 1;
 169                                 else            tpars.tdir = 2;
 170                                 tpars.heading = planes[i].ahdg;
 171                                 if      (planes[i].alt-planes[i].aalt > 100.0)  tpars.VDir = 1;
 172                                 else if (planes[i].alt-planes[i].aalt < -100.0) tpars.VDir = 3;
 173                                 else tpars.VDir = 2;
 174                                 tpars.alt = planes[i].aalt;
 175                                 message = current_transmissionlist->gen_text(station, code, tpars, true );
 176                                 //cout << message << '\n';
 177                                 globals->get_ATC_display()->RegisterSingleMessage( message, 0 );
 178                                 planes[i].lmc = code;
 179                                 planes[i].tlm = etime_node->getDoubleValue();
 180                                 planes[i].on_crs = true;
 181                                 planes[i].contact = 1;
 182                         }
 183                 //}
 184
 185                 //if(1) {
 186                 if ( planes[i].contact == 1 ) {
 187                         // =========================
 188                         // === update parameters ===
 189                         // =========================
 190                         update_param( i );
 191                         //cout << planes[i].brg << " " << planes[i].dist << " " << planes[i].wpts[wpn+1][0]
 192                         //<< " " << planes[i].wpts[wpn+1][1] << " " << planes[i].wpts[wpn+1][4]
 193                         //cout << wpn << " distance to current course = " << planes[i].dcc << endl;
 194                         //cout << etime_node->getDoubleValue() << endl;
 195
 196                         // =========================
 197                         // === reached waypoint? ===
 198                         // =========================
 199                         wpn = planes[i].wpn-2;
 200                         adif = angle_diff_deg( planes[i].hdg, planes[i].wpts[wpn][4] )
 201                         * SGD_DEGREES_TO_RADIANS;
 202                         datp = 2*sin(fabs(adif)/2.0)*sin(fabs(adif)/2.0) *
 203                                planes[i].spd/3600. * planes[i].turn_rate +
 204                                planes[i].spd/3600. * 3.0;
 205                         //cout << adif/SGD_DEGREES_TO_RADIANS << " "
 206                         //     << datp << " " << planes[i].dnc << " " << planes[i].dcc <<endl;
 207                         if ( fabs(planes[i].dnc) < datp ) {
 208                         //if ( fabs(planes[i].dnc) < 0.3 && planes[i].dnwp < 1.0 ) {
 209                                 //cout << "Reached next waypoint!\n";
 210                                 planes[i].wpn -= 1;
 211                                 wpn = planes[i].wpn-1;
 212                                 planes[i].ahdg = planes[i].wpts[wpn][4];
 213                                 planes[i].aalt = planes[i].wpts[wpn-1][2];
 214                                 planes[i].wp_change = true;
 215
 216                                 // generate the message
 217                                 adif = angle_diff_deg( planes[i].hdg, planes[i].ahdg );
 218                                 tpars.station = name;
 219                                 tpars.callsign = "Player";
 220                                 if ( adif < 0 ) tpars.tdir = 1;
 221                                 else            tpars.tdir = 2;
 222                                 tpars.heading = planes[i].ahdg;
 223
 224                                 if ( wpn-1 != 0) {
 225                                         code.c1 = 1;
 226                                         code.c2 = 1;
 227                                         code.c3 = 0;
 228                                         if      (planes[i].alt-planes[i].aalt > 100.0)  tpars.VDir = 1;
 229                                         else if (planes[i].alt-planes[i].aalt < -100.0) tpars.VDir = 3;
 230                                         else tpars.VDir = 2;
 231                                         tpars.alt = planes[i].aalt;
 232                                         message = current_transmissionlist->gen_text(station, code, tpars, true );
 233                                         //cout << "Approach transmitting...\n";
 234                                         //cout << message << endl;
 235                                         globals->get_ATC_display()->RegisterSingleMessage( message, 0 );
 236
 237                                 }
 238                                 else {
 239                                         code.c1 = 1;
 240                                         code.c2 = 3;
 241                                         code.c3 = 0;
 242                                         tpars.runway = active_runway;
 243                                         message = current_transmissionlist->gen_text(station, code, tpars, true);
 244                                         //cout << "Approach transmitting 2 ...\n";
 245                                         //cout << message << endl;
 246                                         globals->get_ATC_display()->RegisterSingleMessage( message, 0 );
 247                                 }
 248                                 planes[i].lmc = code;
 249                                 planes[i].tlm = etime_node->getDoubleValue();
 250                                 planes[i].on_crs = true;
 251
 252                                 update_param( i );
 253                         }
 254
 255                         // =========================
 256                         // === come off course ? ===
 257                         // =========================
 258                         if ( fabs(planes[i].dcc) > 1.0 &&
 259                            ( !planes[i].wp_change || etime_node->getDoubleValue() - planes[i].tlm > tbm ) ) {
 260                                 //cout << "Off course!\n";
 261                                 if ( planes[i].on_crs ) {
 262                                         if ( planes[i].dcc < 0) {
 263                                                 planes[i].ahdg += 30.0;
 264                                         }
 265                                         else {
 266                                                 planes[i].ahdg -= 30.0;
 267                                         }
 268                                         if (planes[i].ahdg > 360.0) planes[i].ahdg -= 360.0;
 269                                         else if (planes[i].ahdg < 0.0) planes[i].ahdg += 360.0;
 270                                 }
 271                                 //cout << planes[i].on_crs << " "
 272                                 //     << angle_diff_deg( planes[i].hdg, planes[i].ahdg) << " "
 273                                 //     << etime_node->getDoubleValue() << " "
 274                                 //     << planes[i].tlm << endl;
 275                                 // generate the message
 276                                 if ( planes[i].on_crs ||
 277                                    ( fabs(angle_diff_deg( planes[i].hdg, planes[i].ahdg )) >  30.0  &&
 278                                     etime_node->getDoubleValue() - planes[i].tlm > tbm) ) {
 279                                         // generate the message
 280                                         code.c1 = 1;
 281                                         code.c2 = 4;
 282                                         code.c3 = 0;
 283                                         adif = angle_diff_deg( planes[i].hdg, planes[i].ahdg );
 284                                         tpars.station = name;
 285                                         tpars.callsign = "Player";
 286                                         tpars.miles   = fabs(planes[i].dcc);
 287                                         if ( adif < 0 ) tpars.tdir = 1;
 288                                         else            tpars.tdir = 2;
 289                                         tpars.heading = planes[i].ahdg;
 290                                         message = current_transmissionlist->gen_text(station, code, tpars, true);
 291                                         //cout << "Approach transmitting 3 ...\n";
 292                                         //cout << message << '\n';
 293                                         globals->get_ATC_display()->RegisterSingleMessage( message, 0 );
 294                                         planes[i].lmc = code;
 295                                         planes[i].tlm = etime_node->getDoubleValue();
 296                                 }
 297
 298                                 planes[i].on_crs = false;
 299                         }
 300                         else if ( !planes[i].on_crs ) {
 301                                 //cout << "Off course 2!\n";
 302                                 wpn = planes[i].wpn-1;
 303                                 adif = angle_diff_deg( planes[i].hdg, planes[i].wpts[wpn][4] )
 304                                        * SGD_DEGREES_TO_RADIANS;
 305                                 datp = 2*sin(fabs(adif)/2.0)*sin(fabs(adif)/2.0) *
 306                                 planes[i].spd/3600. * planes[i].turn_rate +
 307                                 planes[i].spd/3600. * 3.0;
 308                                 if ( fabs(planes[i].dcc) < datp ) {
 309                                         planes[i].ahdg = fabs(planes[i].wpts[wpn][4]);
 310
 311                                         // generate the message
 312                                         code.c1 = 1;
 313                                         code.c2 = 2;
 314                                         code.c3 = 0;
 315                                         tpars.station = name;
 316                                         tpars.callsign = "Player";
 317                                         if ( adif < 0 ) tpars.tdir = 1;
 318                                         else            tpars.tdir = 2;
 319                                         tpars.heading = planes[i].ahdg;
 320                                         message = current_transmissionlist->gen_text(station, code, tpars, true);
 321                                         //cout << "Approach transmitting 4 ...\n";
 322                                         //cout << message << '\n';
 323                                         globals->get_ATC_display()->RegisterSingleMessage( message, 0 );
 324                                         planes[i].lmc = code;
 325                                         planes[i].tlm = etime_node->getDoubleValue();
 326
 327                                         planes[i].on_crs = true;
 328                                 }
 329                         }
 330                         else if ( planes[i].wp_change  ) {
 331                                 planes[i].wp_change = false;
 332                         }
 333
 334                         // ===================================================================
 335                         // === Less than two minutes away from touchdown? -> Contact Tower ===
 336                         // ===================================================================
 337                         if ( planes[i].wpn == 2 && planes[i].dnwp < planes[i].spd/60.*2.0 ) {
 338
 339                                 double freq = 121.95;   // Hardwired - FIXME
 340                                 // generate message
 341                                 code.c1 = 1;
 342                                 code.c2 = 5;
 343                                 code.c3 = 0;
 344                                 tpars.station = name;
 345                                 tpars.callsign = "Player";
 346                                 tpars.freq    = freq;
 347                                 message = current_transmissionlist->gen_text(station, code, tpars, true);
 348                                 //cout << "Approach transmitting 5 ...\n";
 349                                 //cout << message << '\n';
 350                                 globals->get_ATC_display()->RegisterSingleMessage( message, 0 );
 351                                 planes[i].lmc = code;
 352                                 planes[i].tlm = etime_node->getDoubleValue();
 353
 354                                 planes[i].contact = 2;
 355                         }
 356                 }
 357         }
 358 }
 359
 360
 361 // ============================================================================
 362 // update course parameters
 363 // ============================================================================
 364 void FGApproach::update_param( const int &i ) {
 365
 366   double course, d;
 367
 368   int wpn = planes[i].wpn-1;            // this is the current waypoint
 369
 370   planes[i].dcc  = calc_psl_dist(planes[i].brg, planes[i].dist,
 371                                  planes[i].wpts[wpn][0], planes[i].wpts[wpn][1],
 372                                  planes[i].wpts[wpn][4]);
 373   planes[i].dnc  = calc_psl_dist(planes[i].brg, planes[i].dist,
 374                                  planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1],
 375                                  planes[i].wpts[wpn-1][4]);
 376   calc_hd_course_dist(planes[i].brg, planes[i].dist,
 377                       planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1],
 378                       &course, &d);
 379   planes[i].dnwp = d;
 380
 381 }
 382
 383 // ============================================================================
 384 // smallest difference between two angles in degree
 385 // difference is negative if a1 > a2 and positive if a2 > a1
 386 // ===========================================================================
 387 double FGApproach::angle_diff_deg( const double &a1, const double &a2) {
 388
 389   double a3 = a2 - a1;
 390   if (a3 < 180.0) a3 += 360.0;
 391   if (a3 > 180.0) a3 -= 360.0;
 392
 393   return a3;
 394 }
 395
 396 // ============================================================================
 397 // calculate waypoints
 398 // ============================================================================
 399 void FGApproach::calc_wp( const int &i ) {
 400
 401         int j;
 402         double course, d, cd, a1;
 403
 404         int wpn = planes[i].wpn;
 405         // waypoint 0: Threshold of active runway
 406         calc_gc_course_dist(Point3D(lon*SGD_DEGREES_TO_RADIANS, lat*SGD_DEGREES_TO_RADIANS, 0.0),
 407                             Point3D(active_rw_lon*SGD_DEGREES_TO_RADIANS,active_rw_lat*SGD_DEGREES_TO_RADIANS, 0.0 ),
 408                             &course, &d);
 409         double d1 = active_rw_hdg+180.0;
 410         if ( d1 > 360.0 ) d1 -=360.0;
 411         calc_cd_head_dist(360.0-course*SGD_RADIANS_TO_DEGREES, d/SG_NM_TO_METER,
 412                           d1, active_rw_len/SG_NM_TO_METER/2.0,
 413                           &planes[i].wpts[wpn][0], &planes[i].wpts[wpn][1]);
 414         planes[i].wpts[wpn][2] = elev;
 415         planes[i].wpts[wpn][4] = 0.0;
 416         planes[i].wpts[wpn][5] = 0.0;
 417         wpn += 1;
 418
 419         // ======================
 420         // horizontal navigation
 421         // ======================
 422         // waypoint 1: point for turning onto final
 423         calc_cd_head_dist(planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1], d1, lfl,
 424                           &planes[i].wpts[wpn][0], &planes[i].wpts[wpn][1]);
 425         calc_hd_course_dist(planes[i].wpts[wpn][0],   planes[i].wpts[wpn][1],
 426                             planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1],
 427                             &course, &d);
 428         planes[i].wpts[wpn][4] = course;
 429         planes[i].wpts[wpn][5] = d;
 430         wpn += 1;
 431
 432         // calculate course and distance from plane position to waypoint 1
 433         calc_hd_course_dist(planes[i].brg, planes[i].dist, planes[i].wpts[1][0],
 434                             planes[i].wpts[1][1], &course, &d);
 435         // check if airport is not between plane and waypoint 1 and
 436         // DCA to airport on course to waypoint 1 is larger than 10 miles
 437         double zero = 0.0;
 438         if ( fabs(angle_diff_deg( planes[i].wpts[1][0], planes[i].brg  )) < 90.0 ||
 439                 calc_psl_dist( zero, zero, planes[i].brg, planes[i].dist, course ) > 10.0 ) {
 440                 // check if turning angle at waypoint 1 would be > max_ta
 441                 if ( fabs(angle_diff_deg( planes[i].wpts[1][4], course )) > max_ta ) {
 442                         cd = calc_psl_dist(planes[i].brg, planes[i].dist,
 443                              planes[i].wpts[1][0], planes[i].wpts[1][1],
 444                              planes[i].wpts[1][4]);
 445                         a1 = atan2(cd,planes[i].wpts[1][1]);
 446                         planes[i].wpts[wpn][0] = planes[i].wpts[1][0] - a1/SGD_DEGREES_TO_RADIANS;
 447                         if ( planes[i].wpts[wpn][0] < 0.0)   planes[i].wpts[wpn][0] += 360.0;
 448                         if ( planes[i].wpts[wpn][0] > 360.0) planes[i].wpts[wpn][0] -= 360.0;
 449                         planes[i].wpts[wpn][1] = fabs(cd) / sin(fabs(a1));
 450                         calc_hd_course_dist(planes[i].wpts[wpn][0],   planes[i].wpts[wpn][1],
 451                                             planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1],
 452                                             &course, &d);
 453                         planes[i].wpts[wpn][4] = course;
 454                         planes[i].wpts[wpn][5] = d;
 455                         wpn += 1;
 456
 457                         calc_hd_course_dist(planes[i].brg, planes[i].dist, planes[i].wpts[wpn-1][0],
 458                                             planes[i].wpts[wpn-1][1], &course, &d);
 459                 }
 460         } else {
 461                 double leg = 10.0;
 462                 a1 = atan2(planes[i].wpts[1][1], leg );
 463
 464                 if ( angle_diff_deg(planes[i].brg,planes[i].wpts[1][0]) < 0 )
 465                         planes[i].wpts[wpn][0] = planes[i].wpts[1][0] + a1/SGD_DEGREES_TO_RADIANS;
 466                 else planes[i].wpts[wpn][0] = planes[i].wpts[1][0] - a1/SGD_DEGREES_TO_RADIANS;
 467
 468                 planes[i].wpts[wpn][1] = sqrt( planes[i].wpts[1][1]*planes[i].wpts[1][1] + leg*leg );
 469                 calc_hd_course_dist(planes[i].wpts[wpn][0],   planes[i].wpts[wpn][1],
 470                                     planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1],
 471                                     &course, &d);
 472                 planes[i].wpts[wpn][4] = course;
 473                 planes[i].wpts[wpn][5] = d;
 474                 wpn += 1;
 475
 476                 calc_hd_course_dist(planes[i].brg, planes[i].dist,
 477                                     planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1],
 478                                     &course, &d);
 479         }
 480
 481         planes[i].wpts[wpn][0] = planes[i].brg;
 482         planes[i].wpts[wpn][1] = planes[i].dist;
 483         planes[i].wpts[wpn][2] = planes[i].alt;
 484         planes[i].wpts[wpn][4] = course;
 485         planes[i].wpts[wpn][5] = d;
 486         wpn += 1;
 487
 488         planes[i].wpn = wpn;
 489
 490         // Now check if legs are too short or if legs can be shortend
 491         // legs must be at least 2 flight minutes long
 492         double mdist = planes[i].spd / 60.0 * 2.0;
 493         for ( j=2; j<wpn-1; ++j ) {
 494                 if ( planes[i].wpts[j][1] < mdist) {
 495                 }
 496         }
 497
 498         // ====================
 499         // vertical navigation
 500         // ====================
 501         double alt = elev+3000.0;
 502         planes[i].wpts[1][2] = round_alt( true, alt );
 503         for ( j=2; j<wpn-1; ++j ) {
 504                 double dalt = planes[i].alt - planes[i].wpts[j-1][2];
 505                 if ( dalt > 0 ) {
 506                         alt = planes[i].wpts[j-1][2] +
 507                               (planes[i].wpts[j][5] / planes[i].spd) * 60.0 * planes[i].desc_rate;
 508                         planes[i].wpts[j][2] = round_alt( false, alt );
 509                         if ( planes[i].wpts[j][2] > planes[i].alt )
 510                                 planes[i].wpts[j][2] = round_alt( false, planes[i].alt );
 511                 }
 512                 else {
 513                         planes[i].wpts[j][2] = planes[i].wpts[1][2];
 514                 }
 515         }
 516
 517         cout << "Plane position: " << planes[i].brg << " " << planes[i].dist << endl;
 518         for ( j=0; j<wpn; ++j ) {
 519                 cout << "Waypoint " << j << endl;
 520                 cout << "------------------" << endl;
 521                 cout << planes[i].wpts[j][0] << "   " << planes[i].wpts[j][1]
 522                      << "   " << planes[i].wpts[j][2] << "   " << planes[i].wpts[j][5];
 523                 cout << endl << endl;
 524         }
 525
 526 }
 527
 528
 529 // ============================================================================
 530 // round altitude value to next highest/lowest 500 feet
 531 // ============================================================================
 532 double FGApproach::round_alt( const bool hl, double alt ) {
 533
 534   alt = alt/1000.0;
 535   if ( hl ) {
 536     if ( alt > (int)(alt)+0.5 ) alt = ((int)(alt)+1)*1000.0;
 537     else alt = ((int)(alt)+0.5)*1000.0;
 538   }
 539   else {
 540     if ( alt > (int)(alt)+0.5 ) alt = ((int)(alt)+0.5)*1000.0;
 541     else alt = ((int)(alt))*1000.0;
 542   }
 543
 544   return alt;
 545 }
 546
 547
 548 // ============================================================================
 549 // get active runway
 550 // ============================================================================
 551 void FGApproach::get_active_runway() {
 552         //cout << "Entering FGApproach::get_active_runway()\n";
 553
 554   FGEnvironment stationweather =
 555       ((FGEnvironmentMgr *)globals->get_subsystem("environment"))
 556         ->getEnvironment(lat, lon, elev);
 557
 558   double hdg = stationweather.get_wind_from_heading_deg();
 559
 560   FGRunway runway;
 561   if ( globals->get_runways()->search( ident, int(hdg), &runway) ) {
 562     active_runway = runway._rwy_no;
 563     active_rw_hdg = runway._heading;
 564     active_rw_lon = runway._lon;
 565     active_rw_lat = runway._lat;
 566     active_rw_len = runway._length;
 567     //cout << "Active runway is: " << active_runway << "  heading = "
 568     // << active_rw_hdg
 569     // << " lon = " << active_rw_lon
 570     // << " lat = " << active_rw_lat <<endl;
 571   }
 572   else cout << "FGRunways search failed\n";
 573
 574 }
 575
 576 // ========================================================================
 577 // update infos about plane
 578 // ========================================================================
 579 void FGApproach::update_plane_dat() {
 580
 581   //cout << "Update Approach " << ident << "   " << num_planes << " registered" << endl;
 582   // update plane positions
 583   int i;
 584   for (i=0; i<num_planes; i++) {
 585     planes[i].lon = lon_node->getDoubleValue();
 586     planes[i].lat = lat_node->getDoubleValue();
 587     planes[i].alt = elev_node->getDoubleValue();
 588     planes[i].hdg = hdg_node->getDoubleValue();
 589     planes[i].spd = speed_node->getDoubleValue();
 590
 591     /*Point3D aircraft = sgGeodToCart( Point3D(planes[i].lon*SGD_DEGREES_TO_RADIANS,
 592                                              planes[i].lat*SGD_DEGREES_TO_RADIANS,
 593                                              planes[i].alt*SG_FEET_TO_METER) );*/
 594     double course, distance;
 595     calc_gc_course_dist(Point3D(lon*SGD_DEGREES_TO_RADIANS, lat*SGD_DEGREES_TO_RADIANS, 0.0),
 596                         Point3D(planes[i].lon*SGD_DEGREES_TO_RADIANS,planes[i].lat*SGD_DEGREES_TO_RADIANS, 0.0 ),
 597                         &course, &distance);
 598     planes[i].dist = distance/SG_NM_TO_METER;
 599     planes[i].brg  = 360.0-course*SGD_RADIANS_TO_DEGREES;
 600
 601     //cout << "Plane Id: " << planes[i].ident << "  Distance to " << ident
 602     // << " is " << planes[i].dist << " miles   " << "Bearing " << planes[i].brg << endl;
 603
 604   }
 605 }
 606
 607 // =======================================================================
 608 // Add plane to Approach list
 609 // =======================================================================
 610 void FGApproach::AddPlane(string pid) {
 611
 612   int i;
 613   for ( i=0; i<num_planes; i++) {
 614     if ( planes[i].ident == pid) {
 615       //cout << "Plane already registered: " << planes[i].ident << ' ' << ident << ' ' << num_planes << endl;
 616       return;
 617     }
 618   }
 619   planes[num_planes].ident = pid;
 620   ++num_planes;
 621   //cout << "Plane added to list: " << ident << " " << num_planes << endl;
 622   return;
 623 }
 624
 625 // ================================================================================
 626 // closest distance between a point (h1,d1) and a straigt line (h2,d2,h3) in 2 dim.
 627 // ================================================================================
 628 double FGApproach::calc_psl_dist(const double &h1, const double &d1,
 629                                  const double &h2, const double &d2,
 630                                  const double &h3)
 631 {
 632   double a1 = h1 * SGD_DEGREES_TO_RADIANS;
 633   double a2 = h2 * SGD_DEGREES_TO_RADIANS;
 634   double a3 = h3 * SGD_DEGREES_TO_RADIANS;
 635   double x1 = cos(a1) * d1;
 636   double y1 = sin(a1) * d1;
 637   double x2 = cos(a2) * d2;
 638   double y2 = sin(a2) * d2;
 639   double x3 = cos(a3);
 640   double y3 = sin(a3);
 641
 642   // formula: dis = sqrt( (v1-v2)**2 - ((v1-v2)*v3)**2 ); vi = (xi,yi)
 643   double val1   = (x1-x2)*(x1-x2) + (y1-y2)*(y1-y2);
 644   double val2   = ((x1-x2)*x3 + (y1-y2)*y3) * ((x1-x2)*x3 + (y1-y2)*y3);
 645   double dis    = val1 - val2;
 646   // now get sign for offset
 647   //cout << x1 << " " << x2 << " " << y1 << " " << y2 << " "
 648   //     << x3 << " " << y3 << " "
 649   //     << val1 << " " << val2 << " " << dis << endl;
 650   x3 *= sqrt(val2);
 651   y3 *= sqrt(val2);
 652   double da = fabs(atan2(y3,x3) - atan2(y1-y2,x1-x2));
 653   if ( da > SGD_PI ) da -= 2*SGD_PI;
 654   if ( fabs(da) > SGD_PI/2.) {
 655     //if ( x3*(x1-x2) < 0.0 && y3*(y1-y2) < 0.0) {
 656     x3 *= -1.0;
 657     y3 *= -1.0;
 658   }
 659   //cout << x3 << " " << y3 << endl;
 660   double dis1   = x1-x2-x3;
 661   double dis2   = y1-y2-y3;
 662   dis = sqrt(dis);
 663   da = atan2(dis2,dis1);
 664   if ( da < 0.0 ) da  += 2*SGD_PI;
 665   if ( da < a3 )  dis *= -1.0;
 666   //cout << dis1 << " " << dis2 << " " << da*SGD_RADIANS_TO_DEGREES << " " << h3
 667   //     << " " << sqrt(dis1*dis1 + dis2*dis2) << " " << dis << endl;
 668   //cout << atan2(dis2,dis1)*SGD_RADIANS_TO_DEGREES << " " << dis << endl;
 669
 670   return dis;
 671 }
 672
 673
 674 // ========================================================================
 675 // Calculate new bear/dist given starting bear/dis, and offset radial,
 676 // and distance.
 677 // ========================================================================
 678 void FGApproach::calc_cd_head_dist(const double &h1, const double &d1,
 679                                    const double &course, const double &dist,
 680                                    double *h2, double *d2)
 681 {
 682   double a1 = h1 * SGD_DEGREES_TO_RADIANS;
 683   double a2 = course * SGD_DEGREES_TO_RADIANS;
 684   double x1 = cos(a1) * d1;
 685   double y1 = sin(a1) * d1;
 686   double x2 = cos(a2) * dist;
 687   double y2 = sin(a2) * dist;
 688
 689   *d2 = sqrt((x1+x2)*(x1+x2) + (y1+y2)*(y1+y2));
 690   *h2 = atan2( (y1+y2), (x1+x2) ) * SGD_RADIANS_TO_DEGREES;
 691   if ( *h2 < 0 ) *h2 = *h2+360;
 692 }
 693
 694
 695
 696 // ========================================================================
 697 // get heading and distance between two points; point1 ---> point2
 698 // ========================================================================
 699 void FGApproach::calc_hd_course_dist(const double &h1, const double &d1,
 700                                      const double &h2, const double &d2,
 701                                      double *course, double *dist)
 702 {
 703   double a1 = h1 * SGD_DEGREES_TO_RADIANS;
 704   double a2 = h2 * SGD_DEGREES_TO_RADIANS;
 705   double x1 = cos(a1) * d1;
 706   double y1 = sin(a1) * d1;
 707   double x2 = cos(a2) * d2;
 708   double y2 = sin(a2) * d2;
 709
 710   *dist   = sqrt( (y2-y1)*(y2-y1) + (x2-x1)*(x2-x1) );
 711   *course = atan2( (y2-y1), (x2-x1) ) * SGD_RADIANS_TO_DEGREES;
 712   if ( *course < 0 ) *course = *course+360;
 713   //cout << x1 << " " << y1 << " " << x2 << " " << y2 << " " << *dist << " " << *course << endl;
 714 }
 715
 716
 717
 718 int FGApproach::RemovePlane() {
 719
 720   // first check if anything has to be done
 721   bool rmplane = false;
 722   int i;
 723
 724   for (i=0; i<num_planes; i++) {
 725     if (planes[i].dist > range*SG_NM_TO_METER) {
 726       rmplane = true;
 727       break;
 728     }
 729   }
 730   if (!rmplane) return num_planes;
 731
 732   // now make a copy of the plane list
 733   PlaneApp tmp[max_planes];
 734   for (i=0; i<num_planes; i++) {
 735     tmp[i] = planes[i];
 736   }
 737
 738   int np = 0;
 739   // now check which planes are still in range
 740   for (i=0; i<num_planes; i++) {
 741     if (tmp[i].dist <= range*SG_NM_TO_METER) {
 742       planes[np] = tmp[i];
 743       np += 1;
 744     }
 745   }
 746   num_planes = np;
 747
 748   return num_planes;
 749 }