src/ATC/tower.cxx

   1 // FGTower - a class to provide tower control at towered airports.
   2 //
   3 // Written by David Luff, started March 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 <Main/globals.hxx>
  22 #include <Airports/runways.hxx>
  23 #include <simgear/math/sg_geodesy.hxx>
  24 #include <simgear/debug/logstream.hxx>
  25
  26 #include "tower.hxx"
  27 #include "ATCdisplay.hxx"
  28 #include "ATCmgr.hxx"
  29 #include "ATCutils.hxx"
  30 #include "commlist.hxx"
  31 #include "AILocalTraffic.hxx"
  32
  33 SG_USING_STD(cout);
  34
  35 // TowerPlaneRec
  36
  37 TowerPlaneRec::TowerPlaneRec() :
  38 clearedToLand(false),
  39 clearedToLineUp(false),
  40 clearedToTakeOff(false),
  41 holdShortReported(false),
  42 longFinalReported(false),
  43 longFinalAcknowledged(false),
  44 finalReported(false),
  45 finalAcknowledged(false),
  46 opType(TTT_UNKNOWN),
  47 isUser(false)
  48 {
  49         plane.callsign = "UNKNOWN";
  50 }
  51
  52 TowerPlaneRec::TowerPlaneRec(PlaneRec p) :
  53 clearedToLand(false),
  54 clearedToLineUp(false),
  55 clearedToTakeOff(false),
  56 holdShortReported(false),
  57 longFinalReported(false),
  58 longFinalAcknowledged(false),
  59 finalReported(false),
  60 finalAcknowledged(false),
  61 opType(TTT_UNKNOWN),
  62 isUser(false)
  63 {
  64         plane = p;
  65 }
  66
  67 TowerPlaneRec::TowerPlaneRec(Point3D pt) :
  68 clearedToLand(false),
  69 clearedToLineUp(false),
  70 clearedToTakeOff(false),
  71 holdShortReported(false),
  72 longFinalReported(false),
  73 longFinalAcknowledged(false),
  74 finalReported(false),
  75 finalAcknowledged(false),
  76 opType(TTT_UNKNOWN),
  77 isUser(false)
  78 {
  79         plane.callsign = "UNKNOWN";
  80         pos = pt;
  81 }
  82
  83 TowerPlaneRec::TowerPlaneRec(PlaneRec p, Point3D pt) :
  84 clearedToLand(false),
  85 clearedToLineUp(false),
  86 clearedToTakeOff(false),
  87 holdShortReported(false),
  88 longFinalReported(false),
  89 longFinalAcknowledged(false),
  90 finalReported(false),
  91 finalAcknowledged(false),
  92 opType(TTT_UNKNOWN),
  93 isUser(false)
  94 {
  95         plane = p;
  96         pos = pt;
  97 }
  98
  99
 100 // FGTower
 101
 102 FGTower::FGTower() {
 103         ATCmgr = globals->get_ATC_mgr();
 104
 105         // Init the property nodes - TODO - need to make sure we're getting surface winds.
 106         wind_from_hdg = fgGetNode("/environment/wind-from-heading-deg", true);
 107         wind_speed_knots = fgGetNode("/environment/wind-speed-kts", true);
 108
 109         holdListItr = holdList.begin();
 110         appListItr = appList.begin();
 111         depListItr = depList.begin();
 112         rwyListItr = rwyList.begin();
 113         circuitListItr = circuitList.begin();
 114         trafficListItr = trafficList.begin();
 115 }
 116
 117 FGTower::~FGTower() {
 118         if(!separateGround) {
 119                 delete ground;
 120         }
 121 }
 122
 123 void FGTower::Init() {
 124     display = false;
 125
 126         // Pointers to user's position
 127         user_lon_node = fgGetNode("/position/longitude-deg", true);
 128         user_lat_node = fgGetNode("/position/latitude-deg", true);
 129         user_elev_node = fgGetNode("/position/altitude-ft", true);
 130         user_hdg_node = fgGetNode("/orientation/heading-deg", true);
 131
 132         // Need some way to initialise rwyOccupied flag correctly if the user is on the runway and to know its the user.
 133         // I'll punt the startup issue for now though!!!
 134         rwyOccupied = false;
 135
 136         // Setup the ground control at this airport
 137         AirportATC a;
 138         //cout << "Tower ident = " << ident << '\n';
 139         if(ATCmgr->GetAirportATCDetails(ident, &a)) {
 140                 if(a.ground_freq) {             // Ground control
 141                         ground = (FGGround*)ATCmgr->GetATCPointer(ident, GROUND);
 142                         separateGround = true;
 143                         if(ground == NULL) {
 144                                 // Something has gone wrong :-(
 145                                 SG_LOG(SG_ATC, SG_WARN, "ERROR - ground has frequency but can't get ground pointer :-(");
 146                                 ground = new FGGround(ident);
 147                                 separateGround = false;
 148                                 ground->Init();
 149                                 if(display) {
 150                                         ground->SetDisplay();
 151                                 } else {
 152                                         ground->SetNoDisplay();
 153                                 }
 154                         }
 155                 } else {
 156                         // Initialise ground anyway to do the shortest path stuff!
 157                         // Note that we're now responsible for updating and deleting this - NOT the ATCMgr.
 158                         ground = new FGGround(ident);
 159                         separateGround = false;
 160                         ground->Init();
 161                         if(display) {
 162                                 ground->SetDisplay();
 163                         } else {
 164                                 ground->SetNoDisplay();
 165                         }
 166                 }
 167         } else {
 168                 SG_LOG(SG_ATC, SG_ALERT, "Unable to find airport details for " << ident << " in FGTower::Init()");
 169                 // Initialise ground anyway to avoid segfault later
 170                 ground = new FGGround(ident);
 171                 separateGround = false;
 172                 ground->Init();
 173                 if(display) {
 174                         ground->SetDisplay();
 175                 } else {
 176                         ground->SetNoDisplay();
 177                 }
 178         }
 179
 180         // Get the airport elevation
 181         aptElev = dclGetAirportElev(ident.c_str()) * SG_FEET_TO_METER;
 182
 183         DoRwyDetails();
 184
 185         // FIXME - this currently assumes use of the active rwy by the user.
 186         rwyOccupied = OnAnyRunway(Point3D(user_lon_node->getDoubleValue(), user_lat_node->getDoubleValue(), 0.0));
 187         if(rwyOccupied) {
 188                 // Assume the user is started at the threshold ready to take-off
 189                 TowerPlaneRec* t = new TowerPlaneRec;
 190                 t->plane.callsign = "Charlie Foxtrot Sierra";   // C-FGFS !!! - fixme - this is a bit hardwired
 191                 t->opType = TTT_UNKNOWN;        // We don't know if the user wants to do circuits or a departure...
 192                 t->leg = TAKEOFF_ROLL;
 193                 t->isUser = true;
 194                 t->planePtr = NULL;
 195                 t->clearedToTakeOff = true;
 196                 rwyList.push_back(t);
 197         }
 198 }
 199
 200 void FGTower::Update(double dt) {
 201         static int ii = 0;      // Counter for spreading the load
 202         int ii_max = 15;
 203         //cout << "T" << flush;
 204         // Each time step, what do we need to do?
 205         // We need to go through the list of outstanding requests and acknowedgements
 206         // and process at least one of them.
 207         // We need to go through the list of planes under our control and check if
 208         // any need to be addressed.
 209         // We need to check for planes not under our control coming within our
 210         // control area and address if necessary.
 211
 212         // TODO - a lot of the below probably doesn't need to be called every frame and should be staggered.
 213
 214         // Sort the arriving planes
 215
 216         // Calculate the eta of each plane to the threshold.
 217         // For ground traffic this is the fastest they can get there.
 218         // For air traffic this is the middle approximation.
 219         if(ii == 1) {
 220                 doThresholdETACalc();
 221         }
 222
 223         // Order the list of traffic as per expected threshold use and flag any conflicts
 224         if(ii == 2) {
 225                 bool conflicts = doThresholdUseOrder();
 226         }
 227
 228         // sortConficts() !!!
 229
 230         // Do one plane from the hold list
 231         if(ii == 4) {
 232                 if(holdList.size()) {
 233                         //cout << "A" << endl;
 234                         //cout << "*holdListItr = " << *holdListItr << endl;
 235                         if(holdListItr == holdList.end()) {
 236                                 holdListItr = holdList.begin();
 237                         }
 238                         //cout << "*holdListItr = " << *holdListItr << endl;
 239                         //Process(*holdListItr);
 240                         TowerPlaneRec* t = *holdListItr;
 241                         //cout << "t = " << t << endl;
 242                         if(t->holdShortReported) {
 243                                 //cout << "B" << endl;
 244                                 double responseTime = 10.0;             // seconds - this should get more sophisticated at some point
 245                                 if(t->clearanceCounter > responseTime) {
 246                                         //cout << "C" << endl;
 247                                         if(t->nextOnRwy) {
 248                                                 //cout << "D" << endl;
 249                                                 if(rwyOccupied) {
 250                                                         //cout << "E" << endl;
 251                                                         // Do nothing for now - consider acknowloging hold short eventually
 252                                                 } else {
 253                                                         // Lets Roll !!!!
 254                                                         string trns = t->plane.callsign;
 255                                                         //if(departed plane < some threshold in time away) {
 256                                                                 if(0) {         // FIXME
 257                                                                         trns += " line up";
 258                                                                         t->clearedToLineUp = true;
 259                                                                         t->planePtr->RegisterTransmission(3);   // cleared to line-up
 260                                                                         t->leg = TAKEOFF_ROLL;
 261                                                         //} else if(arriving plane < some threshold away) {
 262                                                                 } else if(0) {  // FIXME
 263                                                                         trns += " cleared immediate take-off";
 264                                                                         // TODO - add traffic is... ?
 265                                                                         t->clearedToTakeOff = true;
 266                                                                         t->planePtr->RegisterTransmission(4);   // cleared to take-off - TODO differentiate between immediate and normal take-off
 267                                                                         t->leg = TAKEOFF_ROLL;
 268                                                                 } else {
 269                                                                         trns += " cleared for take-off";
 270                                                                         // TODO - add traffic is... ?
 271                                                                         t->clearedToTakeOff = true;
 272                                                                         t->planePtr->RegisterTransmission(4);   // cleared to take-off
 273                                                                         t->leg = TAKEOFF_ROLL;
 274                                                                 }
 275                                                                 if(display) {
 276                                                                         globals->get_ATC_display()->RegisterSingleMessage(trns, 0);
 277                                                                 }
 278                                                                 t->holdShortReported = false;
 279                                                                 t->clearanceCounter = 0;
 280                                                                 rwyList.push_back(t);
 281                                                                 rwyOccupied = true;
 282                                                                 holdList.erase(holdListItr);
 283                                                                 holdListItr = holdList.begin();
 284                                                 }
 285                                         } else {
 286                                                 // possibly tell him to hold and what position he is?
 287                                         }
 288                                 } else {
 289                                         t->clearanceCounter += (dt * holdList.size() * ii_max);
 290                                 }
 291                         }
 292                         ++holdListItr;
 293                 }
 294         }
 295
 296         // Do the runway list - we'll do the whole runway list since it's important and there'll never be many planes on the rwy at once!!
 297         if(ii == 5) {
 298                 if(rwyOccupied) {
 299                         if(!rwyList.size()) {
 300                                 rwyOccupied = false;
 301                         } else {
 302                                 rwyListItr = rwyList.begin();
 303                                 TowerPlaneRec* t = *rwyListItr;
 304                                 if(t->isUser) {
 305                                         bool on_rwy = OnActiveRunway(Point3D(user_lon_node->getDoubleValue(), user_lat_node->getDoubleValue(), 0.0));
 306                                         // TODO - how do we find the position when it's not the user?
 307                                         if(!on_rwy) {
 308                                                 if((t->opType == INBOUND) || (t->opType == STRAIGHT_IN)) {
 309                                                         rwyList.pop_front();
 310                                                         delete t;
 311                                                         // TODO - tell it to taxi / contact ground / don't delete it etc!
 312                                                 } else if(t->opType == OUTBOUND) {
 313                                                         depList.push_back(t);
 314                                                         rwyList.pop_front();
 315                                                 } else if(t->opType == CIRCUIT) {
 316                                                         circuitList.push_back(t);
 317                                                         rwyList.pop_front();
 318                                                 } else if(t->opType == TTT_UNKNOWN) {
 319                                                         depList.push_back(t);
 320                                                         circuitList.push_back(t);
 321                                                         rwyList.pop_front();
 322                                                 } else {
 323                                                         // HELP - we shouldn't ever get here!!!
 324                                                 }
 325                                         }
 326                                 } // else TODO figure out what to do when it's not the user
 327                         }
 328                 }
 329         }
 330
 331         // do the ciruit list
 332         if(ii == 6) {
 333                 // Clear the constraints - we recalculate here.
 334                 base_leg_pos = 0.0;
 335                 downwind_leg_pos = 0.0;
 336                 crosswind_leg_pos = 0.0;
 337                 if(circuitList.size()) {
 338                         circuitListItr = circuitList.begin();   // TODO - at the moment we're constraining plane 2 based on plane 1 - this won't work for 3 planes in the circuit!!
 339                         TowerPlaneRec* t = *circuitListItr;
 340                         Point3D tortho = ortho.ConvertToLocal(t->pos);
 341                         if(t->isUser) {
 342                                 // Need to figure out which leg he's on
 343                                 double ho = GetAngleDiff_deg(user_hdg_node->getDoubleValue(), rwy.hdg);
 344                                 // TODO FIXME - get the wind and convert this to track, or otherwise use track somehow!!!
 345                                 // If it's gusty might need to filter the value, although we are leaving 30 degrees each way leeway!
 346                                 if(abs(ho) < 30) {
 347                                         // could be either takeoff, climbout or landing - check orthopos.y
 348                                         if((tortho.y() < 0) || (t->leg == TURN4) || (t->leg == LANDING_ROLL)) {
 349                                                 t->leg = LANDING_ROLL;
 350                                                 //cout << "Landing_roll\n";
 351                                         } else {
 352                                                 t->leg = CLIMBOUT;      // TODO - check elev wrt. apt elev to differentiate takeoff roll and climbout
 353                                                 //cout << "Climbout\n";
 354                                         }
 355                                 } else if(abs(ho) < 60) {
 356                                         // turn1 or turn 4
 357                                         // TODO - either fix or doublecheck this hack by looking at heading and pattern direction
 358                                         if((t->leg == CLIMBOUT) || (t->leg == TURN1)) {
 359                                                 t->leg = TURN1;
 360                                                 //cout << "Turn1\n";
 361                                         } else {
 362                                                 t->leg = TURN4;
 363                                                 //cout << "Turn4\n";
 364                                         }
 365                                 } else if(abs(ho) < 120) {
 366                                         // crosswind or base
 367                                         // TODO - either fix or doublecheck this hack by looking at heading and pattern direction
 368                                         if((t->leg == TURN1) || (t->leg == CROSSWIND)) {
 369                                                 t->leg = CROSSWIND;
 370                                                 //cout << "Crosswind\n";
 371                                         } else {
 372                                                 t->leg = BASE;
 373                                                 //cout << "Base\n";
 374                                         }
 375                                 } else if(abs(ho) < 150) {
 376                                         // turn2 or turn 3
 377                                         // TODO - either fix or doublecheck this hack by looking at heading and pattern direction
 378                                         if((t->leg == CROSSWIND) || (t->leg == TURN2)) {
 379                                                 t->leg = TURN2;
 380                                                 //cout << "Turn2\n";
 381                                         } else {
 382                                                 t->leg = TURN3;
 383                                                 //cout << "Turn3\n";
 384                                         }
 385                                 } else {
 386                                         // downwind
 387                                         t->leg = DOWNWIND;
 388                                         //cout << "Downwind\n";
 389                                 }
 390                         } else {
 391                                 t->leg = t->planePtr->GetLeg();
 392                         }
 393                         switch(t->leg) {
 394                         case FINAL:
 395                                 // Base leg must be at least as far out as the plane is - actually possibly not necessary for separation, but we'll use that for now.
 396                                 base_leg_pos = tortho.y();
 397                                 break;
 398                         case TURN4:
 399                                 // Fall through to base
 400                         case BASE:
 401                                 base_leg_pos = tortho.y();
 402                                 break;
 403                         case TURN3:
 404                                 // Fall through to downwind
 405                         case DOWNWIND:
 406                                 // Only have the downwind leg pos as turn-to-base constraint if more negative than we already have.
 407                                 base_leg_pos = (tortho.y() < base_leg_pos ? tortho.y() : base_leg_pos);
 408                                 downwind_leg_pos = tortho.x();          // Assume that a following plane can simply be constrained by the immediately in front downwind plane
 409                                 break;
 410                         case TURN2:
 411                                 // Fall through to crosswind
 412                         case CROSSWIND:
 413                                 crosswind_leg_pos = tortho.y();
 414                                 break;
 415                         case TURN1:
 416                                 // Fall through to climbout
 417                         case CLIMBOUT:
 418                                 // Only use current by constraint as largest
 419                                 crosswind_leg_pos = (tortho.y() > crosswind_leg_pos ? tortho.x() : crosswind_leg_pos);
 420                                 break;
 421                         case TAKEOFF_ROLL:
 422                                 break;
 423                         case LEG_UNKNOWN:
 424                                 break;
 425                         case LANDING_ROLL:
 426                                 break;
 427                         default:
 428                                 break;
 429                         }
 430                 }
 431         }
 432
 433         doCommunication();
 434
 435         if(!separateGround) {
 436                 // The display stuff might have to get more clever than this when not separate
 437                 // since the tower and ground might try communicating simultaneously even though
 438                 // they're mean't to be the same contoller/frequency!!
 439                 if(display) {
 440                         ground->SetDisplay();
 441                 } else {
 442                         ground->SetNoDisplay();
 443                 }
 444                 ground->Update(dt);
 445         }
 446
 447         ++ii;
 448         // How big should ii get - ie how long should the update cycle interval stretch?
 449         if(ii >= ii_max) {
 450                 ii = 0;
 451         }
 452 }
 453
 454
 455 // Figure out which runways are active.
 456 // For now we'll just be simple and do one active runway - eventually this will get much more complex
 457 // This is a private function - public interface to the results of this is through GetActiveRunway
 458 void FGTower::DoRwyDetails() {
 459         //cout << "GetRwyDetails called" << endl;
 460
 461         // Based on the airport-id and wind get the active runway
 462         SGPath path( globals->get_fg_root() );
 463         path.append( "Airports" );
 464         path.append( "runways.mk4" );
 465         FGRunways runways( path.c_str() );
 466
 467         //wind
 468         double hdg = wind_from_hdg->getDoubleValue();
 469         double speed = wind_speed_knots->getDoubleValue();
 470         hdg = (speed == 0.0 ? 270.0 : hdg);
 471         //cout << "Heading = " << hdg << '\n';
 472
 473         FGRunway runway;
 474         bool rwyGood = runways.search(ident, int(hdg), &runway);
 475         if(rwyGood) {
 476                 activeRwy = runway.rwy_no;
 477                 rwy.rwyID = runway.rwy_no;
 478                 SG_LOG(SG_ATC, SG_INFO, "Active runway for airport " << ident << " is " << activeRwy);
 479
 480                 // Get the threshold position
 481                 double other_way = runway.heading - 180.0;
 482                 while(other_way <= 0.0) {
 483                         other_way += 360.0;
 484                 }
 485         // move to the +l end/center of the runway
 486                 //cout << "Runway center is at " << runway.lon << ", " << runway.lat << '\n';
 487         Point3D origin = Point3D(runway.lon, runway.lat, aptElev);
 488                 Point3D ref = origin;
 489         double tshlon, tshlat, tshr;
 490                 double tolon, tolat, tor;
 491                 rwy.length = runway.length * SG_FEET_TO_METER;
 492                 rwy.width = runway.width * SG_FEET_TO_METER;
 493         geo_direct_wgs_84 ( aptElev, ref.lat(), ref.lon(), other_way,
 494                                 rwy.length / 2.0 - 25.0, &tshlat, &tshlon, &tshr );
 495         geo_direct_wgs_84 ( aptElev, ref.lat(), ref.lon(), runway.heading,
 496                                 rwy.length / 2.0 - 25.0, &tolat, &tolon, &tor );
 497                 // Note - 25 meters in from the runway end is a bit of a hack to put the plane ahead of the user.
 498                 // now copy what we need out of runway into rwy
 499         rwy.threshold_pos = Point3D(tshlon, tshlat, aptElev);
 500                 Point3D takeoff_end = Point3D(tolon, tolat, aptElev);
 501                 //cout << "Threshold position = " << tshlon << ", " << tshlat << ", " << aptElev << '\n';
 502                 //cout << "Takeoff position = " << tolon << ", " << tolat << ", " << aptElev << '\n';
 503                 rwy.hdg = runway.heading;
 504                 // Set the projection for the local area based on this active runway
 505                 ortho.Init(rwy.threshold_pos, rwy.hdg);
 506                 rwy.end1ortho = ortho.ConvertToLocal(rwy.threshold_pos);        // should come out as zero
 507                 rwy.end2ortho = ortho.ConvertToLocal(takeoff_end);
 508         } else {
 509                 SG_LOG(SG_ATC, SG_ALERT, "Help  - can't get good runway in FGTower!!");
 510                 activeRwy = "NN";
 511         }
 512 }
 513
 514
 515 // Figure out if a given position lies on the active runway
 516 // Might have to change when we consider more than one active rwy.
 517 bool FGTower::OnActiveRunway(Point3D pt) {
 518         // TODO - check that the centre calculation below isn't confused by displaced thesholds etc.
 519         Point3D xyc((rwy.end1ortho.x() + rwy.end2ortho.x())/2.0, (rwy.end1ortho.y() + rwy.end2ortho.y())/2.0, 0.0);
 520         Point3D xyp = ortho.ConvertToLocal(pt);
 521
 522         //cout << "Length offset = " << fabs(xyp.y() - xyc.y()) << '\n';
 523         //cout << "Width offset = " << fabs(xyp.x() - xyc.x()) << '\n';
 524
 525         double rlen = rwy.length/2.0 + 5.0;
 526         double rwidth = rwy.width/2.0;
 527         double ldiff = fabs(xyp.y() - xyc.y());
 528         double wdiff = fabs(xyp.x() - xyc.x());
 529
 530         return((ldiff < rlen) && (wdiff < rwidth));
 531 }
 532
 533
 534 // Figure out if a given position lies on any runway or not
 535 // Only call this at startup - reading the runways database is expensive and needs to be fixed!
 536 bool FGTower::OnAnyRunway(Point3D pt) {
 537         ATCData ad;
 538         double dist = current_commlist->FindClosest(lon, lat, elev, ad, TOWER, 10.0);
 539         if(dist < 0.0) {
 540                 return(false);
 541         }
 542         // Based on the airport-id, go through all the runways and check for a point in them
 543         SGPath spath( globals->get_fg_root() );
 544         spath.append( "Airports" );
 545         spath.append( "runways.mk4" );
 546         FGRunways runways( spath.c_str() );
 547
 548         // TODO - do we actually need to search for the airport - surely we already know our ident and
 549         // can just search runways of our airport???
 550         //cout << "Airport ident is " << ad.ident << '\n';
 551         FGRunway runway;
 552         bool rwyGood = runways.search(ad.ident, &runway);
 553         if(!rwyGood) {
 554                 SG_LOG(SG_ATC, SG_WARN, "Unable to find any runways for airport ID " << ad.ident << " in FGTower");
 555         }
 556         bool on = false;
 557         while(runway.id == ad.ident) {
 558                 on = OnRunway(pt, runway);
 559                 //cout << "Runway " << runway.rwy_no << ": On = " << (on ? "true\n" : "false\n");
 560                 if(on) return(true);
 561                 runways.next(&runway);
 562         }
 563         return(on);
 564 }
 565
 566
 567 // Calculate the eta of each plane to the threshold.
 568 // For ground traffic this is the fastest they can get there.
 569 // For air traffic this is the middle approximation.
 570 void FGTower::doThresholdETACalc() {
 571         // For now we'll be very crude and hardwire expected speeds to C172-like values
 572         // The speeds below are specified in knots IAS and then converted to m/s
 573         double app_ias = 100.0 * 0.514444;                      // Speed during straight-in approach
 574         double circuit_ias = 80.0 * 0.514444;           // Speed around circuit
 575         double final_ias = 70.0 * 0.514444;             // Speed during final approach
 576
 577         tower_plane_rec_list_iterator twrItr;
 578
 579         // Sign convention - dist_out is -ve for approaching planes and +ve for departing planes
 580         // dist_across is +ve in the pattern direction - ie a plane correctly on downwind will have a +ve dist_across
 581         for(twrItr = trafficList.begin(); twrItr != trafficList.end(); twrItr++) {
 582                 TowerPlaneRec* tpr = *twrItr;
 583                 Point3D op = ortho.ConvertToLocal(tpr->pos);
 584                 double dist_out_m = op.y();
 585                 double dist_across_m = fabs(op.x());    // FIXME = the fabs is a hack to cope with the fact that we don't know the circuit direction yet
 586                 //cout << "Doing ETA calc for " << tpr->plane.callsign << '\n';
 587                 if(tpr->opType == CIRCUIT) {
 588                         // It's complicated - depends on if base leg is delayed or not
 589                         if(tpr->leg == LANDING_ROLL) {
 590                                 tpr->eta = 0;
 591                         } else if((tpr->leg == FINAL) || (tpr->leg == TURN4)) {
 592                                 tpr->eta = fabs(dist_out_m) / final_ias;
 593                         } else if((tpr->leg == BASE) || (tpr->leg == TURN3)) {
 594                                 tpr->eta = (fabs(dist_out_m) / final_ias) + (dist_across_m / circuit_ias);
 595                         } else {
 596                                 // Need to calculate where base leg is likely to be
 597                                 // FIXME - for now I'll hardwire it to 1000m which is what AILocalTraffic uses!!!
 598                                 // TODO - as a matter of design - AILocalTraffic should get the nominal no-traffic base turn distance from Tower, since in real life the published pattern might differ from airport to airport
 599                                 double nominal_base_dist_out_m = -1000;
 600                                 double current_base_dist_out_m = nominal_base_dist_out_m;
 601                                 double nominal_dist_across_m = 1000;    // Hardwired value from AILocalTraffic
 602                                 double nominal_cross_dist_out_m = 1000; // Bit of a guess - AI plane turns to crosswind at 600ft agl.
 603                                 tpr->eta = fabs(current_base_dist_out_m) / final_ias;   // final
 604                                 if((tpr->leg == DOWNWIND) || (tpr->leg == TURN2)) {
 605                                         tpr->eta += dist_across_m / circuit_ias;
 606                                         tpr->eta += fabs(current_base_dist_out_m - dist_out_m) / circuit_ias;
 607                                 } else if((tpr->leg == CROSSWIND) || (tpr->leg == TURN1)) {
 608                                         tpr->eta += nominal_dist_across_m / circuit_ias;        // should we use the dist across of the previous plane if there is previous still on downwind?
 609                                         tpr->eta += fabs(current_base_dist_out_m - nominal_cross_dist_out_m) / circuit_ias;
 610                                         tpr->eta += (nominal_dist_across_m - dist_across_m) / circuit_ias;
 611                                 } else {
 612                                         // We've only just started - why not use a generic estimate?
 613                                 }
 614                         }
 615                 } else if((tpr->opType == INBOUND) || (tpr->opType == STRAIGHT_IN)) {
 616                         // It's simpler!
 617                 } else {
 618                         // Must be outbound - ignore it!
 619                 }
 620                 //cout << "ETA = " << tpr->eta << '\n';
 621         }
 622 }
 623
 624
 625 bool FGTower::doThresholdUseOrder() {
 626         return(true);
 627 }
 628
 629 void FGTower::doCommunication() {
 630 }
 631
 632 void FGTower::ContactAtHoldShort(PlaneRec plane, FGAIPlane* requestee, tower_traffic_type operation) {
 633         // HACK - assume that anything contacting at hold short is new for now - FIXME LATER
 634         TowerPlaneRec* t = new TowerPlaneRec;
 635         t->plane = plane;
 636         t->planePtr = requestee;
 637         t->holdShortReported = true;
 638         t->clearanceCounter = 0;
 639         t->clearedToLineUp = false;
 640         t->clearedToTakeOff = false;
 641         t->opType = operation;
 642
 643         // HACK ALERT - THIS IS HARDWIRED FOR TESTING - FIXME TODO ETC
 644         t->nextOnRwy = true;
 645
 646         //cout << "t = " << t << '\n';
 647
 648         holdList.push_back(t);
 649 }
 650
 651 void FGTower::RequestLandingClearance(string ID) {
 652         //cout << "Request Landing Clearance called...\n";
 653 }
 654 void FGTower::RequestDepartureClearance(string ID) {
 655         //cout << "Request Departure Clearance called...\n";
 656 }
 657 //void FGTower::ReportFinal(string ID);
 658 //void FGTower::ReportLongFinal(string ID);
 659 //void FGTower::ReportOuterMarker(string ID);
 660 //void FGTower::ReportMiddleMarker(string ID);
 661 //void FGTower::ReportInnerMarker(string ID);
 662 //void FGTower::ReportGoingAround(string ID);
 663 void FGTower::ReportRunwayVacated(string ID) {
 664         //cout << "Report Runway Vacated Called...\n";
 665 }