1 // FGApproach - a class to provide approach control at larger airports.
3 // Written by Alexander Kappes, started March 2002.
5 // Copyright (C) 2002 Alexander Kappes
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.
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.
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.
25 #include "approach.hxx"
26 #include "transmission.hxx"
27 #include "transmissionlist.hxx"
28 #include "ATCdisplay.hxx"
29 #include "ATCDialog.hxx"
31 #include <Airports/runways.hxx>
32 #include <simgear/constants.h>
33 #include <simgear/math/polar3d.hxx>
34 #include <simgear/misc/sg_path.hxx>
36 #include <Environment/environment_mgr.hxx>
37 #include <Environment/environment.hxx>
43 FGApproach::FGApproach(){
44 comm1_node = fgGetNode("/instrumentation/comm[0]/frequencies/selected-mhz", true);
45 comm2_node = fgGetNode("/instrumentation/comm[1]/frequencies/selected-mhz", true);
50 lon_node = fgGetNode("/position/longitude-deg", true);
51 lat_node = fgGetNode("/position/latitude-deg", true);
52 elev_node = fgGetNode("/position/altitude-ft", true);
53 hdg_node = fgGetNode("/orientation/heading-deg", true);
54 speed_node = fgGetNode("/velocities/airspeed-kt", true);
55 etime_node = fgGetNode("/sim/time/elapsed-sec", true);
60 for ( i=0; i<max_planes; i++) {
61 planes[i].contact = 0;
63 planes[i].dnwp = -999.;
64 planes[i].on_crs = true;
65 planes[i].turn_rate = 10.0;
66 planes[i].desc_rate = 1000.0;
67 planes[i].clmb_rate = 500.0;
71 planes[i].lmc.c3 = -1;
72 planes[i].wp_change = false;
77 FGApproach::~FGApproach(){
80 void FGApproach::Init() {
85 // ============================================================================
86 // the main update function
87 // ============================================================================
88 void FGApproach::Update(double dt) {
90 const int max_trans = 20;
91 FGTransmission tmissions[max_trans];
93 atc_type station = APPROACH;
101 //static string atcmsg1[10];
102 //static string atcmsg2[10];
106 //static bool TransDisplayed = false;
109 if ( active_runway == "" ) get_active_runway();
111 double comm1_freq = comm1_node->getDoubleValue();
113 //bool DisplayTransmissions = true;
115 for (i=0; i<num_planes; i++) {
116 if ( planes[i].ident == "Player") {
118 tpars.station = name;
119 tpars.callsign = "Player";
120 tpars.airport = ident;
122 //cout << "ident = " << ident << " name = " << name << '\n';
125 // is the frequency of the station tuned in?
126 if ( freq == (int)(comm1_freq*100.0 + 0.5) ) {
127 current_transmissionlist->query_station( station, tmissions, max_trans, num_trans );
128 // loop over all transmissions for station
129 for ( j=0; j<=num_trans-1; j++ ) {
130 code = tmissions[j].get_code();
131 //cout << "code is " << code.c1 << " " << code.c2 << " " << code.c3 << '\n';
132 // select proper transmissions
133 if(code.c3 != 2) { // DCL - hack to prevent request crossing airspace being displayed since this isn't implemented yet.
134 if ( ( code.c2 == -1 && planes[i].lmc.c3 == 0 ) ||
135 ( code.c1 == 0 && code.c2 == planes[i].lmc.c2 ) ) {
136 mentry = current_transmissionlist->gen_text(station, code, tpars, false);
137 transm = current_transmissionlist->gen_text(station, code, tpars, true);
138 // is the transmission already registered?
139 if (!current_atcdialog->trans_reg( ident, transm, APPROACH )) {
140 current_atcdialog->add_entry( ident, transm, mentry, APPROACH, 0 );
149 for ( i=0; i<num_planes; i++ ) {
150 //cout << "TPar.airport = " << TPar.airport << " TPar.station = " << TPar.station << " TPar.callsign = " << TPar.callsign << '\n';
151 //if ( planes[i].ident == TPar.callsign && name == TPar.airport && TPar.station == "approach" ) {
152 //if ( TPar.request && TPar.intention == "landing" && ident == TPar.intid) {
153 if(planes[i].ident == "Player" && fgGetBool("/sim/atc/opt0")) {
154 //cout << "Landing requested\n";
155 fgSetBool("/sim/atc/opt0", false);
157 // ===========================
158 // === calculate waypoints ===
159 // ===========================
162 wpn = planes[i].wpn-1;
163 planes[i].aalt = planes[i].wpts[wpn-1][2];
164 planes[i].ahdg = planes[i].wpts[wpn][4];
166 // generate the message
170 adif = angle_diff_deg( planes[i].hdg, planes[i].ahdg );
171 tpars.station = name;
172 tpars.callsign = "Player";
173 if ( adif < 0 ) tpars.tdir = 1;
175 tpars.heading = planes[i].ahdg;
176 if (planes[i].alt-planes[i].aalt > 100.0) tpars.VDir = 1;
177 else if (planes[i].alt-planes[i].aalt < -100.0) tpars.VDir = 3;
179 tpars.alt = planes[i].aalt;
180 message = current_transmissionlist->gen_text(station, code, tpars, true );
181 //cout << message << '\n';
182 globals->get_ATC_display()->RegisterSingleMessage( message, 0 );
183 planes[i].lmc = code;
184 planes[i].tlm = etime_node->getDoubleValue();
185 planes[i].on_crs = true;
186 planes[i].contact = 1;
191 if ( planes[i].contact == 1 ) {
192 // =========================
193 // === update parameters ===
194 // =========================
196 //cout << planes[i].brg << " " << planes[i].dist << " " << planes[i].wpts[wpn+1][0]
197 //<< " " << planes[i].wpts[wpn+1][1] << " " << planes[i].wpts[wpn+1][4]
198 //cout << wpn << " distance to current course = " << planes[i].dcc << endl;
199 //cout << etime_node->getDoubleValue() << endl;
201 // =========================
202 // === reached waypoint? ===
203 // =========================
204 wpn = planes[i].wpn-2;
205 adif = angle_diff_deg( planes[i].hdg, planes[i].wpts[wpn][4] )
206 * SGD_DEGREES_TO_RADIANS;
207 datp = 2*sin(fabs(adif)/2.0)*sin(fabs(adif)/2.0) *
208 planes[i].spd/3600. * planes[i].turn_rate +
209 planes[i].spd/3600. * 3.0;
210 //cout << adif/SGD_DEGREES_TO_RADIANS << " "
211 // << datp << " " << planes[i].dnc << " " << planes[i].dcc <<endl;
212 if ( fabs(planes[i].dnc) < datp ) {
213 //if ( fabs(planes[i].dnc) < 0.3 && planes[i].dnwp < 1.0 ) {
214 //cout << "Reached next waypoint!\n";
216 wpn = planes[i].wpn-1;
217 planes[i].ahdg = planes[i].wpts[wpn][4];
218 planes[i].aalt = planes[i].wpts[wpn-1][2];
219 planes[i].wp_change = true;
221 // generate the message
222 adif = angle_diff_deg( planes[i].hdg, planes[i].ahdg );
223 tpars.station = name;
224 tpars.callsign = "Player";
225 if ( adif < 0 ) tpars.tdir = 1;
227 tpars.heading = planes[i].ahdg;
233 if (planes[i].alt-planes[i].aalt > 100.0) tpars.VDir = 1;
234 else if (planes[i].alt-planes[i].aalt < -100.0) tpars.VDir = 3;
236 tpars.alt = planes[i].aalt;
237 message = current_transmissionlist->gen_text(station, code, tpars, true );
238 //cout << "Approach transmitting...\n";
239 //cout << message << endl;
240 globals->get_ATC_display()->RegisterSingleMessage( message, 0 );
247 tpars.runway = active_runway;
248 message = current_transmissionlist->gen_text(station, code, tpars, true);
249 //cout << "Approach transmitting 2 ...\n";
250 //cout << message << endl;
251 globals->get_ATC_display()->RegisterSingleMessage( message, 0 );
253 planes[i].lmc = code;
254 planes[i].tlm = etime_node->getDoubleValue();
255 planes[i].on_crs = true;
260 // =========================
261 // === come off course ? ===
262 // =========================
263 if ( fabs(planes[i].dcc) > 1.0 &&
264 ( !planes[i].wp_change || etime_node->getDoubleValue() - planes[i].tlm > tbm ) ) {
265 //cout << "Off course!\n";
266 if ( planes[i].on_crs ) {
267 if ( planes[i].dcc < 0) {
268 planes[i].ahdg += 30.0;
271 planes[i].ahdg -= 30.0;
273 if (planes[i].ahdg > 360.0) planes[i].ahdg -= 360.0;
274 else if (planes[i].ahdg < 0.0) planes[i].ahdg += 360.0;
276 //cout << planes[i].on_crs << " "
277 // << angle_diff_deg( planes[i].hdg, planes[i].ahdg) << " "
278 // << etime_node->getDoubleValue() << " "
279 // << planes[i].tlm << endl;
280 // generate the message
281 if ( planes[i].on_crs ||
282 ( fabs(angle_diff_deg( planes[i].hdg, planes[i].ahdg )) > 30.0 &&
283 etime_node->getDoubleValue() - planes[i].tlm > tbm) ) {
284 // generate the message
288 adif = angle_diff_deg( planes[i].hdg, planes[i].ahdg );
289 tpars.station = name;
290 tpars.callsign = "Player";
291 tpars.miles = fabs(planes[i].dcc);
292 if ( adif < 0 ) tpars.tdir = 1;
294 tpars.heading = planes[i].ahdg;
295 message = current_transmissionlist->gen_text(station, code, tpars, true);
296 //cout << "Approach transmitting 3 ...\n";
297 //cout << message << '\n';
298 globals->get_ATC_display()->RegisterSingleMessage( message, 0 );
299 planes[i].lmc = code;
300 planes[i].tlm = etime_node->getDoubleValue();
303 planes[i].on_crs = false;
305 else if ( !planes[i].on_crs ) {
306 //cout << "Off course 2!\n";
307 wpn = planes[i].wpn-1;
308 adif = angle_diff_deg( planes[i].hdg, planes[i].wpts[wpn][4] )
309 * SGD_DEGREES_TO_RADIANS;
310 datp = 2*sin(fabs(adif)/2.0)*sin(fabs(adif)/2.0) *
311 planes[i].spd/3600. * planes[i].turn_rate +
312 planes[i].spd/3600. * 3.0;
313 if ( fabs(planes[i].dcc) < datp ) {
314 planes[i].ahdg = fabs(planes[i].wpts[wpn][4]);
316 // generate the message
320 tpars.station = name;
321 tpars.callsign = "Player";
322 if ( adif < 0 ) tpars.tdir = 1;
324 tpars.heading = planes[i].ahdg;
325 message = current_transmissionlist->gen_text(station, code, tpars, true);
326 //cout << "Approach transmitting 4 ...\n";
327 //cout << message << '\n';
328 globals->get_ATC_display()->RegisterSingleMessage( message, 0 );
329 planes[i].lmc = code;
330 planes[i].tlm = etime_node->getDoubleValue();
332 planes[i].on_crs = true;
335 else if ( planes[i].wp_change ) {
336 planes[i].wp_change = false;
339 // ===================================================================
340 // === Less than two minutes away from touchdown? -> Contact Tower ===
341 // ===================================================================
342 if ( planes[i].wpn == 2 && planes[i].dnwp < planes[i].spd/60.*2.0 ) {
344 double freq = 121.95; // Hardwired - FIXME
349 tpars.station = name;
350 tpars.callsign = "Player";
352 message = current_transmissionlist->gen_text(station, code, tpars, true);
353 //cout << "Approach transmitting 5 ...\n";
354 //cout << message << '\n';
355 globals->get_ATC_display()->RegisterSingleMessage( message, 0 );
356 planes[i].lmc = code;
357 planes[i].tlm = etime_node->getDoubleValue();
359 planes[i].contact = 2;
366 // ============================================================================
367 // update course parameters
368 // ============================================================================
369 void FGApproach::update_param( const int &i ) {
373 int wpn = planes[i].wpn-1; // this is the current waypoint
375 planes[i].dcc = calc_psl_dist(planes[i].brg, planes[i].dist,
376 planes[i].wpts[wpn][0], planes[i].wpts[wpn][1],
377 planes[i].wpts[wpn][4]);
378 planes[i].dnc = calc_psl_dist(planes[i].brg, planes[i].dist,
379 planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1],
380 planes[i].wpts[wpn-1][4]);
381 calc_hd_course_dist(planes[i].brg, planes[i].dist,
382 planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1],
388 // ============================================================================
389 // smallest difference between two angles in degree
390 // difference is negative if a1 > a2 and positive if a2 > a1
391 // ===========================================================================
392 double FGApproach::angle_diff_deg( const double &a1, const double &a2) {
395 if (a3 < 180.0) a3 += 360.0;
396 if (a3 > 180.0) a3 -= 360.0;
401 // ============================================================================
402 // calculate waypoints
403 // ============================================================================
404 void FGApproach::calc_wp( const int &i ) {
407 double course, d, cd, a1;
409 int wpn = planes[i].wpn;
410 // waypoint 0: Threshold of active runway
411 calc_gc_course_dist(Point3D(lon*SGD_DEGREES_TO_RADIANS, lat*SGD_DEGREES_TO_RADIANS, 0.0),
412 Point3D(active_rw_lon*SGD_DEGREES_TO_RADIANS,active_rw_lat*SGD_DEGREES_TO_RADIANS, 0.0 ),
414 double d1 = active_rw_hdg+180.0;
415 if ( d1 > 360.0 ) d1 -=360.0;
416 calc_cd_head_dist(360.0-course*SGD_RADIANS_TO_DEGREES, d/SG_NM_TO_METER,
417 d1, active_rw_len/SG_NM_TO_METER/2.0,
418 &planes[i].wpts[wpn][0], &planes[i].wpts[wpn][1]);
419 planes[i].wpts[wpn][2] = elev;
420 planes[i].wpts[wpn][4] = 0.0;
421 planes[i].wpts[wpn][5] = 0.0;
424 // ======================
425 // horizontal navigation
426 // ======================
427 // waypoint 1: point for turning onto final
428 calc_cd_head_dist(planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1], d1, lfl,
429 &planes[i].wpts[wpn][0], &planes[i].wpts[wpn][1]);
430 calc_hd_course_dist(planes[i].wpts[wpn][0], planes[i].wpts[wpn][1],
431 planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1],
433 planes[i].wpts[wpn][4] = course;
434 planes[i].wpts[wpn][5] = d;
437 // calculate course and distance from plane position to waypoint 1
438 calc_hd_course_dist(planes[i].brg, planes[i].dist, planes[i].wpts[1][0],
439 planes[i].wpts[1][1], &course, &d);
440 // check if airport is not between plane and waypoint 1 and
441 // DCA to airport on course to waypoint 1 is larger than 10 miles
443 if ( fabs(angle_diff_deg( planes[i].wpts[1][0], planes[i].brg )) < 90.0 ||
444 calc_psl_dist( zero, zero, planes[i].brg, planes[i].dist, course ) > 10.0 ) {
445 // check if turning angle at waypoint 1 would be > max_ta
446 if ( fabs(angle_diff_deg( planes[i].wpts[1][4], course )) > max_ta ) {
447 cd = calc_psl_dist(planes[i].brg, planes[i].dist,
448 planes[i].wpts[1][0], planes[i].wpts[1][1],
449 planes[i].wpts[1][4]);
450 a1 = atan2(cd,planes[i].wpts[1][1]);
451 planes[i].wpts[wpn][0] = planes[i].wpts[1][0] - a1/SGD_DEGREES_TO_RADIANS;
452 if ( planes[i].wpts[wpn][0] < 0.0) planes[i].wpts[wpn][0] += 360.0;
453 if ( planes[i].wpts[wpn][0] > 360.0) planes[i].wpts[wpn][0] -= 360.0;
454 planes[i].wpts[wpn][1] = fabs(cd) / sin(fabs(a1));
455 calc_hd_course_dist(planes[i].wpts[wpn][0], planes[i].wpts[wpn][1],
456 planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1],
458 planes[i].wpts[wpn][4] = course;
459 planes[i].wpts[wpn][5] = d;
462 calc_hd_course_dist(planes[i].brg, planes[i].dist, planes[i].wpts[wpn-1][0],
463 planes[i].wpts[wpn-1][1], &course, &d);
467 a1 = atan2(planes[i].wpts[1][1], leg );
469 if ( angle_diff_deg(planes[i].brg,planes[i].wpts[1][0]) < 0 )
470 planes[i].wpts[wpn][0] = planes[i].wpts[1][0] + a1/SGD_DEGREES_TO_RADIANS;
471 else planes[i].wpts[wpn][0] = planes[i].wpts[1][0] - a1/SGD_DEGREES_TO_RADIANS;
473 planes[i].wpts[wpn][1] = sqrt( planes[i].wpts[1][1]*planes[i].wpts[1][1] + leg*leg );
474 calc_hd_course_dist(planes[i].wpts[wpn][0], planes[i].wpts[wpn][1],
475 planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1],
477 planes[i].wpts[wpn][4] = course;
478 planes[i].wpts[wpn][5] = d;
481 calc_hd_course_dist(planes[i].brg, planes[i].dist,
482 planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1],
486 planes[i].wpts[wpn][0] = planes[i].brg;
487 planes[i].wpts[wpn][1] = planes[i].dist;
488 planes[i].wpts[wpn][2] = planes[i].alt;
489 planes[i].wpts[wpn][4] = course;
490 planes[i].wpts[wpn][5] = d;
495 // Now check if legs are too short or if legs can be shortend
496 // legs must be at least 2 flight minutes long
497 double mdist = planes[i].spd / 60.0 * 2.0;
498 for ( j=2; j<wpn-1; ++j ) {
499 if ( planes[i].wpts[j][1] < mdist) {
503 // ====================
504 // vertical navigation
505 // ====================
506 double alt = elev+3000.0;
507 planes[i].wpts[1][2] = round_alt( true, alt );
508 for ( j=2; j<wpn-1; ++j ) {
509 double dalt = planes[i].alt - planes[i].wpts[j-1][2];
511 alt = planes[i].wpts[j-1][2] +
512 (planes[i].wpts[j][5] / planes[i].spd) * 60.0 * planes[i].desc_rate;
513 planes[i].wpts[j][2] = round_alt( false, alt );
514 if ( planes[i].wpts[j][2] > planes[i].alt )
515 planes[i].wpts[j][2] = round_alt( false, planes[i].alt );
518 planes[i].wpts[j][2] = planes[i].wpts[1][2];
522 cout << "Plane position: " << planes[i].brg << " " << planes[i].dist << endl;
523 for ( j=0; j<wpn; ++j ) {
524 cout << "Waypoint " << j << endl;
525 cout << "------------------" << endl;
526 cout << planes[i].wpts[j][0] << " " << planes[i].wpts[j][1]
527 << " " << planes[i].wpts[j][2] << " " << planes[i].wpts[j][5];
528 cout << endl << endl;
534 // ============================================================================
535 // round altitude value to next highest/lowest 500 feet
536 // ============================================================================
537 double FGApproach::round_alt( const bool hl, double alt ) {
541 if ( alt > (int)(alt)+0.5 ) alt = ((int)(alt)+1)*1000.0;
542 else alt = ((int)(alt)+0.5)*1000.0;
545 if ( alt > (int)(alt)+0.5 ) alt = ((int)(alt)+0.5)*1000.0;
546 else alt = ((int)(alt))*1000.0;
553 // ============================================================================
555 // ============================================================================
556 void FGApproach::get_active_runway() {
557 //cout << "Entering FGApproach::get_active_runway()\n";
559 FGEnvironment stationweather =
560 ((FGEnvironmentMgr *)globals->get_subsystem("environment"))
561 ->getEnvironment(lat, lon, elev);
563 double hdg = stationweather.get_wind_from_heading_deg();
566 if ( globals->get_runways()->search( ident, int(hdg), &runway) ) {
567 active_runway = runway._rwy_no;
568 active_rw_hdg = runway._heading;
569 active_rw_lon = runway._lon;
570 active_rw_lat = runway._lat;
571 active_rw_len = runway._length;
572 //cout << "Active runway is: " << active_runway << " heading = "
574 // << " lon = " << active_rw_lon
575 // << " lat = " << active_rw_lat <<endl;
577 else cout << "FGRunways search failed\n";
581 // ========================================================================
582 // update infos about plane
583 // ========================================================================
584 void FGApproach::update_plane_dat() {
586 //cout << "Update Approach " << ident << " " << num_planes << " registered" << endl;
587 // update plane positions
589 for (i=0; i<num_planes; i++) {
590 planes[i].lon = lon_node->getDoubleValue();
591 planes[i].lat = lat_node->getDoubleValue();
592 planes[i].alt = elev_node->getDoubleValue();
593 planes[i].hdg = hdg_node->getDoubleValue();
594 planes[i].spd = speed_node->getDoubleValue();
596 /*Point3D aircraft = sgGeodToCart( Point3D(planes[i].lon*SGD_DEGREES_TO_RADIANS,
597 planes[i].lat*SGD_DEGREES_TO_RADIANS,
598 planes[i].alt*SG_FEET_TO_METER) );*/
599 double course, distance;
600 calc_gc_course_dist(Point3D(lon*SGD_DEGREES_TO_RADIANS, lat*SGD_DEGREES_TO_RADIANS, 0.0),
601 Point3D(planes[i].lon*SGD_DEGREES_TO_RADIANS,planes[i].lat*SGD_DEGREES_TO_RADIANS, 0.0 ),
603 planes[i].dist = distance/SG_NM_TO_METER;
604 planes[i].brg = 360.0-course*SGD_RADIANS_TO_DEGREES;
606 //cout << "Plane Id: " << planes[i].ident << " Distance to " << ident
607 // << " is " << planes[i].dist << " miles " << "Bearing " << planes[i].brg << endl;
612 // =======================================================================
613 // Add plane to Approach list
614 // =======================================================================
615 void FGApproach::AddPlane(const string& pid) {
618 for ( i=0; i<num_planes; i++) {
619 if ( planes[i].ident == pid) {
620 //cout << "Plane already registered: " << planes[i].ident << ' ' << ident << ' ' << num_planes << endl;
624 planes[num_planes].ident = pid;
626 //cout << "Plane added to list: " << ident << " " << num_planes << endl;
630 // ================================================================================
631 // closest distance between a point (h1,d1) and a straigt line (h2,d2,h3) in 2 dim.
632 // ================================================================================
633 double FGApproach::calc_psl_dist(const double &h1, const double &d1,
634 const double &h2, const double &d2,
637 double a1 = h1 * SGD_DEGREES_TO_RADIANS;
638 double a2 = h2 * SGD_DEGREES_TO_RADIANS;
639 double a3 = h3 * SGD_DEGREES_TO_RADIANS;
640 double x1 = cos(a1) * d1;
641 double y1 = sin(a1) * d1;
642 double x2 = cos(a2) * d2;
643 double y2 = sin(a2) * d2;
647 // formula: dis = sqrt( (v1-v2)**2 - ((v1-v2)*v3)**2 ); vi = (xi,yi)
648 double val1 = (x1-x2)*(x1-x2) + (y1-y2)*(y1-y2);
649 double val2 = ((x1-x2)*x3 + (y1-y2)*y3) * ((x1-x2)*x3 + (y1-y2)*y3);
650 double dis = val1 - val2;
651 // now get sign for offset
652 //cout << x1 << " " << x2 << " " << y1 << " " << y2 << " "
653 // << x3 << " " << y3 << " "
654 // << val1 << " " << val2 << " " << dis << endl;
657 double da = fabs(atan2(y3,x3) - atan2(y1-y2,x1-x2));
658 if ( da > SGD_PI ) da -= SGD_2PI;
659 if ( fabs(da) > SGD_PI_2) {
660 //if ( x3*(x1-x2) < 0.0 && y3*(y1-y2) < 0.0) {
664 //cout << x3 << " " << y3 << endl;
665 double dis1 = x1-x2-x3;
666 double dis2 = y1-y2-y3;
668 da = atan2(dis2,dis1);
669 if ( da < 0.0 ) da += SGD_2PI;
670 if ( da < a3 ) dis *= -1.0;
671 //cout << dis1 << " " << dis2 << " " << da*SGD_RADIANS_TO_DEGREES << " " << h3
672 // << " " << sqrt(dis1*dis1 + dis2*dis2) << " " << dis << endl;
673 //cout << atan2(dis2,dis1)*SGD_RADIANS_TO_DEGREES << " " << dis << endl;
679 // ========================================================================
680 // Calculate new bear/dist given starting bear/dis, and offset radial,
682 // ========================================================================
683 void FGApproach::calc_cd_head_dist(const double &h1, const double &d1,
684 const double &course, const double &dist,
685 double *h2, double *d2)
687 double a1 = h1 * SGD_DEGREES_TO_RADIANS;
688 double a2 = course * SGD_DEGREES_TO_RADIANS;
689 double x1 = cos(a1) * d1;
690 double y1 = sin(a1) * d1;
691 double x2 = cos(a2) * dist;
692 double y2 = sin(a2) * dist;
694 *d2 = sqrt((x1+x2)*(x1+x2) + (y1+y2)*(y1+y2));
695 *h2 = atan2( (y1+y2), (x1+x2) ) * SGD_RADIANS_TO_DEGREES;
696 if ( *h2 < 0 ) *h2 = *h2+360;
701 // ========================================================================
702 // get heading and distance between two points; point1 ---> point2
703 // ========================================================================
704 void FGApproach::calc_hd_course_dist(const double &h1, const double &d1,
705 const double &h2, const double &d2,
706 double *course, double *dist)
708 double a1 = h1 * SGD_DEGREES_TO_RADIANS;
709 double a2 = h2 * SGD_DEGREES_TO_RADIANS;
710 double x1 = cos(a1) * d1;
711 double y1 = sin(a1) * d1;
712 double x2 = cos(a2) * d2;
713 double y2 = sin(a2) * d2;
715 *dist = sqrt( (y2-y1)*(y2-y1) + (x2-x1)*(x2-x1) );
716 *course = atan2( (y2-y1), (x2-x1) ) * SGD_RADIANS_TO_DEGREES;
717 if ( *course < 0 ) *course = *course+360;
718 //cout << x1 << " " << y1 << " " << x2 << " " << y2 << " " << *dist << " " << *course << endl;
723 int FGApproach::RemovePlane() {
725 // first check if anything has to be done
726 bool rmplane = false;
729 for (i=0; i<num_planes; i++) {
730 if (planes[i].dist > range*SG_NM_TO_METER) {
735 if (!rmplane) return num_planes;
737 // now make a copy of the plane list
738 PlaneApp tmp[max_planes];
739 for (i=0; i<num_planes; i++) {
744 // now check which planes are still in range
745 for (i=0; i<num_planes; i++) {
746 if (tmp[i].dist <= range*SG_NM_TO_METER) {