src/ATC/ATCmgr.cxx

   1 // ATCmgr.cxx - Implementation of FGATCMgr - a global Flightgear ATC manager.
   2 //
   3 // Written by David Luff, started February 2002.
   4 //
   5 // Copyright (C) 2002  David C Luff - david.luff@nottingham.ac.uk
   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 <Time/event.hxx>
  22
  23 #include <simgear/misc/sg_path.hxx>
  24 #include <simgear/misc/commands.hxx>
  25 #include <simgear/debug/logstream.hxx>
  26
  27 #include "ATCmgr.hxx"
  28 #include "commlist.hxx"
  29 //#include "atislist.hxx"
  30 //#include "groundlist.hxx"
  31 //#include "towerlist.hxx"
  32 //#include "approachlist.hxx"
  33 #include "ATCdisplay.hxx"
  34
  35 /*
  36 // periodic radio station search wrapper
  37 static void fgATCSearch( void ) {
  38         globals->get_ATC_mgr()->Search();
  39 }
  40 */ //This wouldn't compile - including Time/event.hxx breaks it :-(
  41
  42 static char* t0 = "Request landing clearance";
  43 static char* t1 = "Request departure clearance";
  44 static char* t2 = "Report Runway vacated";
  45 static char** towerOptions = new char*[4];
  46 static char* a0 = "Request vectors";
  47 static char** approachOptions = new char*[2];
  48
  49 // For the ATC dialog - copied from the Autopilot new heading dialog code!
  50 static puDialogBox*             atcDialog;
  51 static puFrame*                 atcDialogFrame;
  52 static puText*                  atcDialogMessage;
  53 //static puInput*                       atcDialogInput;
  54 static puOneShot*               atcDialogOkButton;
  55 static puOneShot*               atcDialogCancelButton;
  56 static puButtonBox*             atcDialogCommunicationOptions;
  57
  58 static void ATCDialogCancel(puObject *)
  59 {
  60     //ATCDialogInput->rejectInput();
  61     FG_POP_PUI_DIALOG( atcDialog );
  62 }
  63
  64 static void ATCDialogOK (puObject *me)
  65 {
  66         // Note that currently the dialog is hardwired to comm1 only here.
  67         switch(globals->get_ATC_mgr()->GetComm1ATCType()) {
  68         case INVALID:
  69                 break;
  70         case ATIS:
  71                 break;
  72         case TOWER: {
  73                 FGTower* twr = (FGTower*)globals->get_ATC_mgr()->GetComm1ATCPointer();
  74                 switch(atcDialogCommunicationOptions->getValue()) {
  75                 case 0:
  76                         //cout << "Option 0 chosen\n";
  77                         twr->RequestLandingClearance("golf bravo echo");
  78                         break;
  79                 case 1:
  80                         //cout << "Option 1 chosen\n";
  81                         twr->RequestDepartureClearance("golf bravo echo");
  82                         break;
  83                 case 2:
  84                         //cout << "Option 2 chosen\n";
  85                         twr->ReportRunwayVacated("golf bravo echo");
  86                         break;
  87                 default:
  88                         break;
  89                 }
  90                 break;
  91         }
  92         case GROUND:
  93                 break;
  94         case APPROACH:
  95                 break;
  96         default:
  97                 break;
  98         }
  99
 100     ATCDialogCancel(me);
 101     //if(error) mkDialog(s.c_str());
 102 }
 103
 104 static void ATCDialog(puObject *cb)
 105 {
 106     //ApHeadingDialogInput   ->    setValue ( heading );
 107     //ApHeadingDialogInput    -> acceptInput();
 108     FG_PUSH_PUI_DIALOG(atcDialog);
 109 }
 110
 111 static void ATCDialogInit()
 112 {
 113         char defaultATCLabel[] = "Enter desired option to communicate with ATC:";
 114         char *s;
 115
 116         // Option lists hardwired per ATC type
 117         towerOptions[0] = new char[strlen(t0)+1];
 118         strcpy(towerOptions[0], t0);
 119         towerOptions[1] = new char[strlen(t1)+1];
 120         strcpy(towerOptions[1], t1);
 121         towerOptions[2] = new char[strlen(t2)+1];
 122         strcpy(towerOptions[2], t2);
 123         towerOptions[3] = NULL;
 124
 125         approachOptions[0] = new char[strlen(a0)+1];
 126         strcpy(approachOptions[0], a0);
 127         approachOptions[1] = NULL;
 128
 129         atcDialog = new puDialogBox (150, 50);
 130         {
 131                 atcDialogFrame   = new puFrame (0, 0, 500, 250);
 132
 133                 atcDialogMessage = new puText          (250, 220);
 134                 atcDialogMessage    -> setDefaultValue (defaultATCLabel);
 135                 atcDialogMessage    -> getDefaultValue (&s);
 136                 atcDialogMessage    -> setLabel        (s);
 137                 atcDialogMessage    -> setLabelPlace   (PUPLACE_TOP_CENTERED);
 138
 139                 atcDialogCommunicationOptions = new puButtonBox (50, 50, 450, 210, NULL, true);
 140
 141                 atcDialogOkButton     =  new puOneShot         (50, 10, 110, 50);
 142                 atcDialogOkButton     ->     setLegend         (gui_msg_OK);
 143                 atcDialogOkButton     ->     makeReturnDefault (TRUE);
 144                 atcDialogOkButton     ->     setCallback       (ATCDialogOK);
 145
 146                 atcDialogCancelButton =  new puOneShot         (140, 10, 210, 50);
 147                 atcDialogCancelButton ->     setLegend         (gui_msg_CANCEL);
 148                 atcDialogCancelButton ->     setCallback       (ATCDialogCancel);
 149
 150         }
 151         FG_FINALIZE_PUI_DIALOG(atcDialog);
 152 }
 153
 154 // For the command manager - maybe eventually this should go in the built in command list
 155 static bool do_ATC_dialog(const SGPropertyNode* arg) {
 156         globals->get_ATC_mgr()->doStandardDialog();
 157         return(true);
 158 }
 159
 160
 161 FGATCMgr::FGATCMgr() {
 162         comm_ident[0] = "";
 163         comm_ident[1] = "";
 164         last_comm_ident[0] = "";
 165         last_comm_ident[1] = "";
 166         approach_ident = "";
 167         last_in_range = false;
 168         comm_type[0] = INVALID;
 169         comm_type[1] = INVALID;
 170         comm_atc_ptr[0] = NULL;
 171         comm_atc_ptr[1] = NULL;
 172 }
 173
 174 FGATCMgr::~FGATCMgr() {
 175 }
 176
 177 void FGATCMgr::bind() {
 178 }
 179
 180 void FGATCMgr::unbind() {
 181 }
 182
 183 void FGATCMgr::init() {
 184         comm_node[0] = fgGetNode("/radios/comm[0]/frequencies/selected-mhz", true);
 185         comm_node[1] = fgGetNode("/radios/comm[1]/frequencies/selected-mhz", true);
 186         lon_node = fgGetNode("/position/longitude-deg", true);
 187         lat_node = fgGetNode("/position/latitude-deg", true);
 188         elev_node = fgGetNode("/position/altitude-ft", true);
 189         atc_list_itr = atc_list.begin();
 190         // Search for connected ATC stations once per 0.8 seconds or so
 191         // global_events.Register( "fgATCSearch()", fgATCSearch,
 192         //                  fgEVENT::FG_EVENT_READY, 800);
 193         // For some reason the above doesn't compile - including Time/event.hxx stops compilation.
 194
 195         // Initialise the frequency search map
 196     current_commlist = new FGCommList;
 197     SGPath p_comm( globals->get_fg_root() );
 198     current_commlist->init( p_comm );
 199
 200         // Initialise the airport_atc_map - we'll cheat for now and just hardcode KEMT and any others that may be needed for development
 201         AirportATC *a = new AirportATC;
 202         a->lon = -118.034719;
 203         a->lat = 34.086114;
 204         a->elev = 296.0;
 205         a->atis_freq = 118.75;
 206         a->atis_active = false;
 207         a->tower_freq = 121.2;
 208         a->tower_active = false;
 209         a->ground_freq = 125.9;
 210         a->ground_active = false;
 211
 212         //a->set_by_AI = true;
 213         //a->set_by_comm_search = false;
 214
 215         airport_atc_map[(string)"KEMT"] = a;
 216
 217 #ifdef ENABLE_AUDIO_SUPPORT
 218         // Load all available voices.
 219         // For now we'll do one hardwired one
 220         voiceOK = v1.LoadVoice("default");
 221         /* I've loaded the voice even if /sim/sound/audible is false
 222         *  since I know no way of forcing load of the voice if the user
 223         *  subsequently switches /sim/sound/audible to true. */
 224 #else
 225         voice = false;
 226 #endif
 227
 228         // Initialise the ATC Dialogs
 229         ATCDialogInit();
 230
 231         // Add ATC-dialog to the command list
 232         globals->get_commands()->addCommand("ATC-dialog", do_ATC_dialog);
 233 }
 234
 235 void FGATCMgr::update(double dt) {
 236         //cout << "Entering update..." << endl;
 237         //Traverse the list of active stations.
 238         //Only update one class per update step to avoid the whole ATC system having to calculate between frames.
 239         //Eventually we should only update every so many steps.
 240         //cout << "In FGATCMgr::update - atc_list.size = " << atc_list.size() << '\n';
 241         if(atc_list.size()) {
 242                 if(atc_list_itr == atc_list.end()) {
 243                         atc_list_itr = atc_list.begin();
 244                 }
 245                 //cout << "Updating " << (*atc_list_itr)->get_ident() << ' ' << (*atc_list_itr)->GetType() << '\n';
 246                 //cout << "Freq = " << (*atc_list_itr)->get_freq() << '\n';
 247                 (*atc_list_itr)->Update();
 248                 //cout << "Done ATC update..." << endl;
 249                 ++atc_list_itr;
 250         }
 251
 252         // Search the tuned frequencies every now and then - this should be done with the event scheduler
 253         static int i = 0;
 254         if(i == 7) {
 255                 AreaSearch();
 256         }
 257         if(i == 15) {
 258                 //cout << "About to search(1)" << endl;
 259                 FreqSearch(1);
 260         }
 261         if(i == 30) {
 262                 //cout << "About to search(2)" << endl;
 263                 FreqSearch(2);
 264                 i = 0;
 265         }
 266         ++i;
 267 }
 268
 269 // Remove from list only if not needed by the AI system or the other comm channel
 270 // TODO - implement me!!
 271 void FGATCMgr::CommRemoveFromList(const char* id, atc_type tp, int chan) {
 272         /*AirportATC a;
 273         if(GetAirportATCDetails((string)id, &a)) {
 274                 if(a.set_by_AI) {
 275                         // Don't remove
 276                         a.set_by_comm_search = false;
 277                         airport_atc_map[(string)id] = a;
 278                         return;
 279                 } else {
 280                         // remove
 281                 }
 282         }*/
 283
 284         // Hack - need to implement this properly
 285         RemoveFromList(id, tp);
 286 }
 287
 288
 289 // Remove from list - should only be called from above or similar
 290 // This function *will* remove it from the list regardless of who else might want it.
 291 void FGATCMgr::RemoveFromList(const char* id, atc_type tp) {
 292         //cout << "Requested type = " << tp << '\n';
 293         //cout << "id = " << id << '\n';
 294         atc_list_itr = atc_list.begin();
 295         while(atc_list_itr != atc_list.end()) {
 296                 //cout << "type = " << (*atc_list_itr)->GetType() << '\n';
 297                 //cout << "Ident = " << (*atc_list_itr)->get_ident() << '\n';
 298                 if( (!strcmp((*atc_list_itr)->get_ident(), id))
 299                         && ((*atc_list_itr)->GetType() == tp) ) {
 300                                 //Before removing it stop it transmitting!!
 301                                 //cout << "OBLITERATING FROM LIST!!!\n";
 302                                 (*atc_list_itr)->SetNoDisplay();
 303                                 (*atc_list_itr)->Update();
 304                                 delete (*atc_list_itr);
 305                                 atc_list_itr = atc_list.erase(atc_list_itr);
 306                                 break;
 307                         }  // Note that that can upset where we are in the list but that doesn't really matter
 308                 ++atc_list_itr;
 309         }
 310 }
 311
 312
 313 // Find in list - return a currently active ATC pointer given ICAO code and type
 314 // Return NULL if the given service is not in the list
 315 // - *** THE CALLING FUNCTION MUST CHECK FOR THIS ***
 316 FGATC* FGATCMgr::FindInList(const char* id, atc_type tp) {
 317         atc_list_itr = atc_list.begin();
 318         while(atc_list_itr != atc_list.end()) {
 319                 if( (!strcmp((*atc_list_itr)->get_ident(), id))
 320                 && ((*atc_list_itr)->GetType() == tp) ) {
 321                         return(*atc_list_itr);
 322                 }       // Note that that can upset where we are in the list but that shouldn't really matter
 323                 ++atc_list_itr;
 324         }
 325         // If we get here it's not in the list
 326         return(NULL);
 327 }
 328
 329 // Returns true if the airport is found in the map
 330 bool FGATCMgr::GetAirportATCDetails(string icao, AirportATC* a) {
 331         if(airport_atc_map.find(icao) != airport_atc_map.end()) {
 332                 *a = *airport_atc_map[icao];
 333                 return(true);
 334         } else {
 335                 return(false);
 336         }
 337 }
 338
 339
 340 // Return a pointer to a given sort of ATC at a given airport and activate if necessary
 341 // ONLY CALL THIS FUNCTION AFTER FIRST CHECKING THE SERVICE EXISTS BY CALLING GetAirportATCDetails
 342 // FIXME - we really ought to take out the necessity for two function calls by simply returning
 343 // a NULL pointer if the service doesn't exist and requiring the caller to check for it (NULL).
 344 FGATC* FGATCMgr::GetATCPointer(string icao, atc_type type) {
 345         AirportATC *a = airport_atc_map[icao];
 346         //cout << "a->lon = " << a->lon << '\n';
 347         //cout << "a->elev = " << a->elev << '\n';
 348         //cout << "a->tower_freq = " << a->tower_freq << '\n';
 349         switch(type) {
 350                 case TOWER:
 351                 if(a->tower_active) {
 352                         // Get the pointer from the list
 353                         return(FindInList(icao.c_str(), type)); // DCL - this untested so far.
 354                 } else {
 355                         FGTower* t = new FGTower;
 356                         ATCData data;
 357                         if(current_commlist->FindByFreq(a->lon, a->lat, a->elev, a->tower_freq, &data, TOWER)) {
 358                                 t->SetData(&data);
 359                                 atc_list.push_back(t);
 360                                 a->tower_active = true;
 361                                 airport_atc_map[icao] = a;
 362                                 return(t);
 363                         } else {
 364                                 cout << "ERROR - tower that should exist in FGATCMgr::GetATCPointer for airport " << icao << " not found\n";
 365                         }
 366                 }
 367                 break;
 368                 // Lets add the rest to get rid of the compiler warnings even though we don't need them yet.
 369                 case APPROACH:
 370                 break;
 371                 case ATIS:
 372                 SG_LOG(SG_GENERAL, SG_ALERT, "ERROR - ATIS station should not be requested from FGATCMgr::GetATCPointer");
 373                 break;
 374                 case GROUND:
 375                 break;
 376                 case INVALID:
 377                 break;
 378                 case ENROUTE:
 379                 break;
 380                 case DEPARTURE:
 381                 break;
 382         }
 383
 384         SG_LOG(SG_GENERAL, SG_ALERT, "ERROR IN FGATCMgr - reached end of GetATCPointer");
 385
 386         return(NULL);
 387 }
 388
 389
 390 // Render a transmission
 391 // Outputs the transmission either on screen or as audio depending on user preference
 392 // The refname is a string to identify this sample to the sound manager
 393 // The repeating flag indicates whether the message should be repeated continuously or played once.
 394 void FGATCMgr::Render(string msg, string refname, bool repeating) {
 395 #ifdef ENABLE_AUDIO_SUPPORT
 396         voice = voiceOK && fgGetBool("/sim/sound/audible");
 397         if(voice) {
 398                 int len;
 399                 unsigned char* buf = v1.WriteMessage((char*)msg.c_str(), len, voice);
 400                 if(voice) {
 401                         FGSimpleSound* simple = new FGSimpleSound(buf, len);
 402                         // TODO - at the moment the volume is always set off comm1
 403                         // and can't be changed after the transmission has started.
 404                         simple->set_volume(5.0 * fgGetDouble("/radios/comm[0]/volume"));
 405                         globals->get_soundmgr()->add(simple, refname);
 406                         if(repeating) {
 407                                 globals->get_soundmgr()->play_looped(refname);
 408                         } else {
 409                                 globals->get_soundmgr()->play_once(refname);
 410                         }
 411                 }
 412                 delete[] buf;
 413         }
 414 #endif  // ENABLE_AUDIO_SUPPORT
 415         if(!voice) {
 416                 // first rip the underscores and the pause hints out of the string - these are for the convienience of the voice parser
 417                 for(unsigned int i = 0; i < msg.length(); ++i) {
 418                         if((msg.substr(i,1) == "_") || (msg.substr(i,1) == "/")) {
 419                                 msg[i] = ' ';
 420                         }
 421                 }
 422                 globals->get_ATC_display()->RegisterRepeatingMessage(msg);
 423         }
 424         playing = true;
 425 }
 426
 427
 428 // Cease rendering a transmission.
 429 void FGATCMgr::NoRender(string refname) {
 430         if(playing) {
 431                 if(voice) {
 432 #ifdef ENABLE_AUDIO_SUPPORT
 433                         globals->get_soundmgr()->stop(refname);
 434                         globals->get_soundmgr()->remove(refname);
 435 #endif
 436                 } else {
 437                         globals->get_ATC_display()->CancelRepeatingMessage();
 438                 }
 439                 playing = false;
 440         }
 441 }
 442
 443
 444 // Display a dialog box with options relevant to the currently tuned ATC service.
 445 void FGATCMgr::doStandardDialog() {
 446         /* DCL 2002/12/06 - This function currently in development
 447            and dosen't display anything usefull to the end-user */
 448         //cout << "FGATCMgr::doStandardDialog called..." << endl;
 449
 450         // First - need to determine which ATC service (if any) the user is tuned to.
 451         //cout << "comm1_type = " << comm1_type << endl;
 452
 453         // Second - customise the dialog box
 454         switch(comm_type[0]) {
 455         case INVALID:
 456                 atcDialogCommunicationOptions->newList(NULL);
 457                 atcDialogMessage->setLabel("Not tuned in to any ATC service.");
 458                 break;
 459         case ATIS:
 460                 atcDialogCommunicationOptions->newList(NULL);
 461                 atcDialogMessage->setLabel("Tuned in to ATIS: no communication possible.");
 462                 break;
 463         case TOWER:
 464                 atcDialogCommunicationOptions->newList(towerOptions);
 465                 atcDialogMessage->setLabel("Tuned in to Tower - select communication to transmit:");
 466                 break;
 467         case GROUND:
 468                 atcDialogCommunicationOptions->newList(NULL);
 469                 atcDialogMessage->setLabel("Tuned in to Ground - select communication to transmit:");
 470                 break;
 471         case APPROACH:
 472                 atcDialogCommunicationOptions->newList(approachOptions);
 473                 atcDialogMessage->setLabel("Tuned in to Approach - select communication to transmit:");
 474                 break;
 475         default:
 476                 atcDialogCommunicationOptions->newList(NULL);
 477                 atcDialogMessage->setLabel("Tuned in to unknown ATC service - enter transmission:");
 478                 break;
 479         }
 480
 481         // Third - display the dialog without pausing sim.
 482         ATCDialog(NULL);
 483
 484         // Forth - need to direct input back from the dialog to the relevant ATC service.
 485         // This is in ATCDialogOK()
 486 }
 487
 488 // Search for ATC stations by frequency
 489 void FGATCMgr::FreqSearch(int channel) {
 490         int chan = channel - 1;         // Convert to zero-based for the arrays
 491
 492         ATCData data;
 493         double freq = comm_node[chan]->getDoubleValue();
 494         lon = lon_node->getDoubleValue();
 495         lat = lat_node->getDoubleValue();
 496         elev = elev_node->getDoubleValue() * SG_FEET_TO_METER;
 497
 498         // Query the data store and get the closest match if any
 499         if(current_commlist->FindByFreq(lon, lat, elev, freq, &data)) {
 500                 // We have a match
 501                 // What's the logic?
 502                 // If this channel not previously valid then easy - add ATC to list
 503                 // If this channel was valid then - Have we tuned to a different service?
 504                 // If so - de-register one and add the other
 505                 if(comm_valid[chan]) {
 506                         if((comm_ident[chan] == data.ident) && (comm_type[chan] == data.type)) {
 507                                 // Then we're still tuned into the same service so do nought and return
 508                                 return;
 509                         } else {
 510                                 // Something's changed - either the location or the service type
 511                                 // We need to feed the channel in so we're not removing it if we're also tuned in on the other channel
 512                                 CommRemoveFromList(comm_ident[chan], comm_type[chan], chan);
 513                         }
 514                 }
 515                 // At this point we can assume that we need to add the service.
 516                 comm_ident[chan] = (data.ident).c_str();
 517                 comm_type[chan] = data.type;
 518                 comm_x[chan] = (double)data.x;
 519                 comm_y[chan] = (double)data.y;
 520                 comm_z[chan] = (double)data.z;
 521                 comm_lon[chan] = (double)data.lon;
 522                 comm_lat[chan] = (double)data.lat;
 523                 comm_elev[chan] = (double)data.elev;
 524                 comm_valid[chan] = true;
 525
 526                 // This was a switch-case statement but the compiler didn't like the new variable creation with it.
 527                 if(comm_type[chan] == ATIS) {
 528                         FGATIS* a = new FGATIS;
 529                         a->SetData(&data);
 530                         comm_atc_ptr[chan] = a;
 531                         a->SetDisplay();
 532                         //a->set_refname((chan) ? "atis2" : "atis1");           // FIXME - that line is limited to 2 channels
 533                         atc_list.push_back(a);
 534                 } else if (comm_type[chan] == TOWER) {
 535                         FGATC* app = FindInList(comm_ident[chan], TOWER);
 536                         if(app != NULL) {
 537                                 // The station is already in the ATC list
 538                                 app->SetDisplay();
 539                         } else {
 540                                 // Generate the station and put in the ATC list
 541                                 FGTower* t = new FGTower;
 542                                 t->SetData(&data);
 543                                 comm_atc_ptr[chan] = t;
 544                                 t->SetDisplay();
 545                                 atc_list.push_back(t);
 546                         }
 547                 } /*else if (comm_type[chan] == APPROACH) {
 548                         // We have to be a bit more carefull here since approaches are also searched by area
 549                         FGATC* app = FindInList(comm_ident[chan], APPROACH);
 550                         if(app != NULL) {
 551                                 // The station is already in the ATC list
 552                                 app->AddPlane("Player");
 553                                 app->SetDisplay();
 554                         } else {
 555                                 // Generate the station and put in the ATC list
 556                                 FGApproach* a = new FGApproach;
 557                                 a->SetData(&data);
 558                                 a->AddPlane("Player");
 559                                 atc_list.push_back(a);
 560                         }
 561                 }*/
 562         } else {
 563                 if(comm_valid[chan]) {
 564                         if(comm_type[chan] != APPROACH) {
 565                                 // Currently approaches are removed by Alexander's out-of-range mechanism
 566                                 CommRemoveFromList(comm_ident[chan], comm_type[chan], chan);
 567                         }
 568                         // Note that we *don't* call SetNoDisplay() here because the other comm channel
 569                         // might be tuned into the same station - this is handled by CommRemoveFromList(...)
 570                         comm_type[chan] = INVALID;
 571                         comm_atc_ptr[chan] = NULL;
 572                         comm_valid[chan] = false;
 573                 }
 574         }
 575 }
 576
 577
 578 // Search ATC stations by area in order that we appear 'on the radar'
 579 void FGATCMgr::AreaSearch() {
 580         // Search for Approach stations
 581         comm_list_type approaches;
 582         comm_list_iterator app_itr;
 583
 584         lon = lon_node->getDoubleValue();
 585         lat = lat_node->getDoubleValue();
 586         elev = elev_node->getDoubleValue() * SG_FEET_TO_METER;
 587
 588         // search stations in range
 589         int num_app = current_commlist->FindByPos(lon, lat, elev, &approaches, APPROACH);
 590         if (num_app != 0) {
 591                 //cout << num_app << " approaches found in radiostack search !!!!" << endl;
 592
 593                 for(app_itr = approaches.begin(); app_itr != approaches.end(); app_itr++) {
 594
 595                         FGATC* app = FindInList((app_itr->ident).c_str(), app_itr->type);
 596                         if(app != NULL) {
 597                                 // The station is already in the ATC list
 598                                 app->AddPlane("Player");
 599                                 //app->Update();
 600                         } else {
 601                                 // Generate the station and put in the ATC list
 602                                 FGApproach* a = new FGApproach;
 603                                 a->SetData(&(*app_itr));
 604                                 a->AddPlane("Player");
 605                                 //a->Update();
 606                                 atc_list.push_back(a);
 607                         }
 608                 }
 609         }
 610
 611         // remove planes which are out of range
 612         // TODO - I'm not entirely sure that this belongs here.
 613         atc_list_itr = atc_list.begin();
 614         while(atc_list_itr != atc_list.end()) {
 615                 if((*atc_list_itr)->GetType() == APPROACH ) {
 616                         int np = (*atc_list_itr)->RemovePlane();
 617                         // if approach has no planes left remove it from ATC list
 618                         if ( np == 0) {
 619                                 (*atc_list_itr)->SetNoDisplay();
 620                                 (*atc_list_itr)->Update();
 621                                 delete (*atc_list_itr);
 622                                 atc_list_itr = atc_list.erase(atc_list_itr);
 623                                 break;     // the other stations will be checked next time
 624                         }
 625                 }
 626                 ++atc_list_itr;
 627         }
 628 }