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.
21 #include "approach.hxx"
22 #include "transmission.hxx"
23 #include "transmissionlist.hxx"
24 #include "ATCdisplay.hxx"
25 #include "ATCDialog.hxx"
27 #include <Airports/runways.hxx>
28 #include <simgear/misc/sg_path.hxx>
31 # include <WeatherCM/FGLocalWeatherDatabase.h>
33 # include <Environment/environment_mgr.hxx>
34 # include <Environment/environment.hxx>
41 FGApproach::FGApproach(){
42 comm1_node = fgGetNode("/radios/comm[0]/frequencies/selected-mhz", true);
43 comm2_node = fgGetNode("/radios/comm[1]/frequencies/selected-mhz", true);
46 lon_node = fgGetNode("/position/longitude-deg", true);
47 lat_node = fgGetNode("/position/latitude-deg", true);
48 elev_node = fgGetNode("/position/altitude-ft", true);
49 hdg_node = fgGetNode("/orientation/heading-deg", true);
50 speed_node = fgGetNode("/velocities/airspeed-kt", true);
51 etime_node = fgGetNode("/sim/time/elapsed-ms", true);
56 for ( i=0; i<max_planes; i++) {
57 planes[i].contact = 0;
59 planes[i].dnwp = -999.;
60 planes[i].on_crs = true;
61 planes[i].turn_rate = 10.0;
62 planes[i].desc_rate = 1000.0;
63 planes[i].clmb_rate = 500.0;
67 planes[i].lmc.c3 = -1;
68 planes[i].wp_change = false;
73 FGApproach::~FGApproach(){
76 void FGApproach::Init() {
82 // ============================================================================
83 // the main update function
84 // ============================================================================
85 void FGApproach::Update(double dt) {
87 const int max_trans = 20;
88 FGTransmission tmissions[max_trans];
98 //static string atcmsg1[10];
99 //static string atcmsg2[10];
103 //static bool TransDisplayed = false;
106 if ( active_runway == "" ) get_active_runway();
108 double comm1_freq = comm1_node->getDoubleValue();
110 //bool DisplayTransmissions = true;
112 for (i=0; i<num_planes; i++) {
113 if ( planes[i].ident == "Player") {
115 tpars.station = name;
116 tpars.callsign = "Player";
117 tpars.airport = ident;
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 // select proper transmissions
127 if ( ( code.c2 == -1 && planes[i].lmc.c3 == 0 ) ||
128 ( code.c1 == 0 && code.c2 == planes[i].lmc.c2 ) ) {
129 mentry = current_transmissionlist->gen_text(station, code, tpars, false);
130 transm = current_transmissionlist->gen_text(station, code, tpars, true);
131 // is the transmission already registered?
132 if (!current_atcdialog->trans_reg( ident, transm )) {
133 current_atcdialog->add_entry( ident, transm, mentry );
141 for ( i=0; i<num_planes; i++ ) {
143 if ( planes[i].ident == TPar.callsign && name == TPar.airport && TPar.station == "approach" ) {
145 if ( TPar.request && TPar.intention == "landing" && ident == TPar.intid) {
147 // ===========================
148 // === calculate waypoints ===
149 // ===========================
152 wpn = planes[i].wpn-1;
153 planes[i].aalt = planes[i].wpts[wpn-1][2];
154 planes[i].ahdg = planes[i].wpts[wpn][4];
156 // generate the message
160 adif = angle_diff_deg( planes[i].hdg, planes[i].ahdg );
161 tpars.station = name;
162 tpars.callsign = "Player";
163 if ( adif < 0 ) tpars.tdir = 1;
165 tpars.heading = planes[i].ahdg;
166 if (planes[i].alt-planes[i].aalt > 100.0) tpars.VDir = 1;
167 else if (planes[i].alt-planes[i].aalt < -100.0) tpars.VDir = 3;
169 tpars.alt = planes[i].aalt;
170 message = current_transmissionlist->gen_text(station, code, tpars, true );
171 globals->get_ATC_display()->RegisterSingleMessage( message, 0 );
172 planes[i].lmc = code;
173 planes[i].tlm = etime_node->getDoubleValue();
174 planes[i].on_crs = true;
175 planes[i].contact = 1;
179 if ( planes[i].contact == 1 ) {
180 // =========================
181 // === update parameters ===
182 // =========================
184 //cout << planes[i].brg << " " << planes[i].dist << " " << planes[i].wpts[wpn+1][0]
185 //<< " " << planes[i].wpts[wpn+1][1] << " " << planes[i].wpts[wpn+1][4]
186 //cout << wpn << " distance to current course = " << planes[i].dcc << endl;
187 //cout << etime_node->getDoubleValue() << endl;
189 // =========================
190 // === reached waypoint? ===
191 // =========================
192 wpn = planes[i].wpn-2;
193 adif = angle_diff_deg( planes[i].hdg, planes[i].wpts[wpn][4] )
194 * SGD_DEGREES_TO_RADIANS;
195 datp = 2*sin(fabs(adif)/2.0)*sin(fabs(adif)/2.0) *
196 planes[i].spd/3600. * planes[i].turn_rate +
197 planes[i].spd/3600. * 3.0;
198 //cout << adif/SGD_DEGREES_TO_RADIANS << " "
199 // << datp << " " << planes[i].dnc << " " << planes[i].dcc <<endl;
200 if ( fabs(planes[i].dnc) < datp ) {
201 //if ( fabs(planes[i].dnc) < 0.3 && planes[i].dnwp < 1.0 ) {
203 wpn = planes[i].wpn-1;
204 planes[i].ahdg = planes[i].wpts[wpn][4];
205 planes[i].aalt = planes[i].wpts[wpn-1][2];
206 planes[i].wp_change = true;
208 // generate the message
209 adif = angle_diff_deg( planes[i].hdg, planes[i].ahdg );
210 tpars.station = name;
211 tpars.callsign = "Player";
212 if ( adif < 0 ) tpars.tdir = 1;
214 tpars.heading = planes[i].ahdg;
220 if (planes[i].alt-planes[i].aalt > 100.0) tpars.VDir = 1;
221 else if (planes[i].alt-planes[i].aalt < -100.0) tpars.VDir = 3;
223 tpars.alt = planes[i].aalt;
224 message = current_transmissionlist->gen_text(station, code, tpars, true );
225 globals->get_ATC_display()->RegisterSingleMessage( message, 0 );
232 tpars.runway = active_runway;
233 message = current_transmissionlist->gen_text(station, code, tpars, true);
234 globals->get_ATC_display()->RegisterSingleMessage( message, 0 );
236 planes[i].lmc = code;
237 planes[i].tlm = etime_node->getDoubleValue();
238 planes[i].on_crs = true;
243 // =========================
244 // === come off course ? ===
245 // =========================
246 if ( fabs(planes[i].dcc) > 1.0 &&
247 ( !planes[i].wp_change ||
248 etime_node->getDoubleValue() - planes[i].tlm > tbm ) ) {
249 if ( planes[i].on_crs ) {
250 if ( planes[i].dcc < 0) {
251 planes[i].ahdg += 30.0;
254 planes[i].ahdg -= 30.0;
256 if (planes[i].ahdg > 360.0) planes[i].ahdg -= 360.0;
257 else if (planes[i].ahdg < 0.0) planes[i].ahdg += 360.0;
259 //cout << planes[i].on_crs << " "
260 // << angle_diff_deg( planes[i].hdg, planes[i].ahdg) << " "
261 // << etime_node->getDoubleValue() << " "
262 // << planes[i].tlm << endl;
263 // generate the message
264 if ( planes[i].on_crs ||
265 ( fabs(angle_diff_deg( planes[i].hdg, planes[i].ahdg )) > 30.0 &&
266 etime_node->getDoubleValue() - planes[i].tlm > tbm) ) {
267 // generate the message
271 adif = angle_diff_deg( planes[i].hdg, planes[i].ahdg );
272 tpars.station = name;
273 tpars.callsign = "Player";
274 tpars.miles = fabs(planes[i].dcc);
275 if ( adif < 0 ) tpars.tdir = 1;
277 tpars.heading = planes[i].ahdg;
278 message = current_transmissionlist->gen_text(station, code, tpars, true);
279 globals->get_ATC_display()->RegisterSingleMessage( message, 0 );
280 planes[i].lmc = code;
281 planes[i].tlm = etime_node->getDoubleValue();
284 planes[i].on_crs = false;
286 else if ( !planes[i].on_crs ) {
287 wpn = planes[i].wpn-1;
288 adif = angle_diff_deg( planes[i].hdg, planes[i].wpts[wpn][4] )
289 * SGD_DEGREES_TO_RADIANS;
290 datp = 2*sin(fabs(adif)/2.0)*sin(fabs(adif)/2.0) *
291 planes[i].spd/3600. * planes[i].turn_rate +
292 planes[i].spd/3600. * 3.0;
293 if ( fabs(planes[i].dcc) < datp ) {
294 planes[i].ahdg = fabs(planes[i].wpts[wpn][4]);
296 // generate the message
300 tpars.station = name;
301 tpars.callsign = "Player";
302 if ( adif < 0 ) tpars.tdir = 1;
304 tpars.heading = planes[i].ahdg;
305 message = current_transmissionlist->gen_text(station, code, tpars, true);
306 globals->get_ATC_display()->RegisterSingleMessage( message, 0 );
307 planes[i].lmc = code;
308 planes[i].tlm = etime_node->getDoubleValue();
310 planes[i].on_crs = true;
313 else if ( planes[i].wp_change ) {
314 planes[i].wp_change = false;
317 // ===================================================================
318 // === Less than two minutes away from touchdown? -> Contact Tower ===
319 // ===================================================================
320 if ( planes[i].wpn == 2 && planes[i].dnwp < planes[i].spd/60.*2.0 ) {
322 double freq = 121.95;
327 tpars.station = name;
328 tpars.callsign = "Player";
330 message = current_transmissionlist->gen_text(station, code, tpars, true);
331 globals->get_ATC_display()->RegisterSingleMessage( message, 0 );
332 planes[i].lmc = code;
333 planes[i].tlm = etime_node->getDoubleValue();
335 planes[i].contact = 2;
343 // ============================================================================
344 // update course parameters
345 // ============================================================================
346 void FGApproach::update_param( const int &i ) {
350 int wpn = planes[i].wpn-1; // this is the current waypoint
352 planes[i].dcc = calc_psl_dist(planes[i].brg, planes[i].dist,
353 planes[i].wpts[wpn][0], planes[i].wpts[wpn][1],
354 planes[i].wpts[wpn][4]);
355 planes[i].dnc = calc_psl_dist(planes[i].brg, planes[i].dist,
356 planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1],
357 planes[i].wpts[wpn-1][4]);
358 calc_hd_course_dist(planes[i].brg, planes[i].dist,
359 planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1],
365 // ============================================================================
366 // smallest difference between two angles in degree
367 // difference is negative if a1 > a2 and positive if a2 > a1
368 // ===========================================================================
369 double FGApproach::angle_diff_deg( const double &a1, const double &a2) {
372 if (a3 < 180.0) a3 += 360.0;
373 if (a3 > 180.0) a3 -= 360.0;
378 // ============================================================================
379 // calculate waypoints
380 // ============================================================================
381 void FGApproach::calc_wp( const int &i ) {
384 double course, d, cd, a1;
386 int wpn = planes[i].wpn;
387 // waypoint 0: Threshold of active runway
388 calc_gc_course_dist(Point3D(lon*SGD_DEGREES_TO_RADIANS, lat*SGD_DEGREES_TO_RADIANS, 0.0),
389 Point3D(active_rw_lon*SGD_DEGREES_TO_RADIANS,active_rw_lat*SGD_DEGREES_TO_RADIANS, 0.0 ),
391 double d1 = active_rw_hdg+180.0;
392 if ( d1 > 360.0 ) d1 -=360.0;
393 calc_cd_head_dist(360.0-course*SGD_RADIANS_TO_DEGREES, d/SG_NM_TO_METER,
394 d1, active_rw_len/SG_NM_TO_METER/2.,
395 &planes[i].wpts[wpn][0], &planes[i].wpts[wpn][1]);
396 planes[i].wpts[wpn][2] = elev;
397 planes[i].wpts[wpn][4] = 0.0;
398 planes[i].wpts[wpn][5] = 0.0;
401 // ======================
402 // horizontal navigation
403 // ======================
404 // waypoint 1: point for turning onto final
405 calc_cd_head_dist(planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1] ,
407 &planes[i].wpts[wpn][0], &planes[i].wpts[wpn][1]);
408 calc_hd_course_dist(planes[i].wpts[wpn][0], planes[i].wpts[wpn][1],
409 planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1],
411 planes[i].wpts[wpn][4] = course;
412 planes[i].wpts[wpn][5] = d;
415 // calculate course and distance from plane position to waypoint 1
416 calc_hd_course_dist(planes[i].brg, planes[i].dist,
417 planes[i].wpts[1][0], planes[i].wpts[1][1],
419 // check if airport is not between plane and waypoint 1 and
420 // DCA to airport on course to waypoint 1 is larger than 10 miles
422 if ( fabs(angle_diff_deg( planes[i].wpts[1][0], planes[i].brg )) < 90.0 ||
423 calc_psl_dist( zero, zero, planes[i].brg, planes[i].dist, course ) > 10.0 ) {
424 // check if turning angle at waypoint 1 would be > max_ta
425 if ( fabs(angle_diff_deg( planes[i].wpts[1][4], course )) > max_ta ) {
426 cd = calc_psl_dist(planes[i].brg, planes[i].dist,
427 planes[i].wpts[1][0], planes[i].wpts[1][1],
428 planes[i].wpts[1][4]);
429 a1 = atan2(cd,planes[i].wpts[1][1]);
430 planes[i].wpts[wpn][0] = planes[i].wpts[1][0] - a1/SGD_DEGREES_TO_RADIANS;
431 if ( planes[i].wpts[wpn][0] < 0.0) planes[i].wpts[wpn][0] += 360.0;
432 if ( planes[i].wpts[wpn][0] > 360.0) planes[i].wpts[wpn][0] -= 360.0;
433 planes[i].wpts[wpn][1] = fabs(cd) / sin(fabs(a1));
434 calc_hd_course_dist(planes[i].wpts[wpn][0], planes[i].wpts[wpn][1],
435 planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1],
437 planes[i].wpts[wpn][4] = course;
438 planes[i].wpts[wpn][5] = d;
441 calc_hd_course_dist(planes[i].brg, planes[i].dist,
442 planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1],
447 a1 = atan2(planes[i].wpts[1][1], leg );
449 if ( angle_diff_deg(planes[i].brg,planes[i].wpts[1][0]) < 0 )
450 planes[i].wpts[wpn][0] = planes[i].wpts[1][0] + a1/SGD_DEGREES_TO_RADIANS;
451 else planes[i].wpts[wpn][0] = planes[i].wpts[1][0] - a1/SGD_DEGREES_TO_RADIANS;
453 planes[i].wpts[wpn][1] = sqrt( planes[i].wpts[1][1]*planes[i].wpts[1][1] + leg*leg );
454 calc_hd_course_dist(planes[i].wpts[wpn][0], planes[i].wpts[wpn][1],
455 planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1],
457 planes[i].wpts[wpn][4] = course;
458 planes[i].wpts[wpn][5] = d;
461 calc_hd_course_dist(planes[i].brg, planes[i].dist,
462 planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1],
466 planes[i].wpts[wpn][0] = planes[i].brg;
467 planes[i].wpts[wpn][1] = planes[i].dist;
468 planes[i].wpts[wpn][2] = planes[i].alt;
469 planes[i].wpts[wpn][4] = course;
470 planes[i].wpts[wpn][5] = d;
475 // Now check if legs are too short or if legs can be shortend
476 // legs must be at least 2 flight minutes long
477 double mdist = planes[i].spd / 60.0 * 2.0;
478 for ( j=2; j<wpn-1; ++j ) {
479 if ( planes[i].wpts[j][1] < mdist) {
483 // ====================
484 // vertical navigation
485 // ====================
486 double alt = elev+3000.0;
487 planes[i].wpts[1][2] = round_alt( true, alt );
488 for ( j=2; j<wpn-1; ++j ) {
489 double dalt = planes[i].alt - planes[i].wpts[j-1][2];
491 alt = planes[i].wpts[j-1][2] +
492 (planes[i].wpts[j][5] / planes[i].spd) * 60.0 * planes[i].desc_rate;
493 planes[i].wpts[j][2] = round_alt( false, alt );
494 if ( planes[i].wpts[j][2] > planes[i].alt )
495 planes[i].wpts[j][2] = round_alt( false, planes[i].alt );
498 planes[i].wpts[j][2] = planes[i].wpts[1][2];
502 cout << "Plane position: " << planes[i].brg << " " << planes[i].dist << endl;
503 for ( j=0; j<wpn; ++j ) {
504 cout << "Waypoint " << j << endl;
505 cout << "------------------" << endl;
506 cout << planes[i].wpts[j][0] << " " << planes[i].wpts[j][1]
507 << " " << planes[i].wpts[j][2] << " " << planes[i].wpts[j][5];
508 cout << endl << endl;
514 // ============================================================================
515 // round altitude value to next highest/lowest 500 feet
516 // ============================================================================
517 double FGApproach::round_alt( const bool hl, double alt ) {
521 if ( alt > (int)(alt)+0.5 ) alt = ((int)(alt)+1)*1000.0;
522 else alt = ((int)(alt)+0.5)*1000.0;
525 if ( alt > (int)(alt)+0.5 ) alt = ((int)(alt)+0.5)*1000.0;
526 else alt = ((int)(alt))*1000.0;
533 // ============================================================================
535 // ============================================================================
536 void FGApproach::get_active_runway() {
539 sgVec3 position = { lat, lon, elev };
540 FGPhysicalProperty stationweather = WeatherDatabase->get(position);
542 FGEnvironment stationweather =
543 ((FGEnvironmentMgr *)globals->get_subsystem("environment"))
544 ->getEnvironment(lat, lon, elev);
548 //Set the heading to into the wind
549 double wind_x = stationweather.Wind[0];
550 double wind_y = stationweather.Wind[1];
552 double speed = sqrt( wind_x*wind_x + wind_y*wind_y ) * SG_METER_TO_NM / (60.0*60.0);
555 //If no wind use 270degrees
559 // //normalize the wind to get the direction
560 //wind_x /= speed; wind_y /= speed;
562 hdg = - atan2 ( wind_x, wind_y ) * SG_RADIANS_TO_DEGREES ;
567 double hdg = stationweather.get_wind_from_heading_deg();
571 if ( globals->get_runways()->search( ident, int(hdg), &runway) ) {
572 active_runway = runway.rwy_no;
573 active_rw_hdg = runway.heading;
574 active_rw_lon = runway.lon;
575 active_rw_lat = runway.lat;
576 active_rw_len = runway.length;
577 //cout << "Active runway is: " << active_runway << " heading = "
579 // << " lon = " << active_rw_lon
580 // << " lat = " << active_rw_lat <<endl;
582 else cout << "FGRunways search failed\n";
586 // ========================================================================
587 // update infos about plane
588 // ========================================================================
589 void FGApproach::update_plane_dat() {
591 //cout << "Update Approach " << ident << " " << num_planes << " registered" << endl;
592 // update plane positions
594 for (i=0; i<num_planes; i++) {
595 planes[i].lon = lon_node->getDoubleValue();
596 planes[i].lat = lat_node->getDoubleValue();
597 planes[i].alt = elev_node->getDoubleValue();
598 planes[i].hdg = hdg_node->getDoubleValue();
599 planes[i].spd = speed_node->getDoubleValue();
601 /*Point3D aircraft = sgGeodToCart( Point3D(planes[i].lon*SGD_DEGREES_TO_RADIANS,
602 planes[i].lat*SGD_DEGREES_TO_RADIANS,
603 planes[i].alt*SG_FEET_TO_METER) );*/
604 double course, distance;
605 calc_gc_course_dist(Point3D(lon*SGD_DEGREES_TO_RADIANS, lat*SGD_DEGREES_TO_RADIANS, 0.0),
606 Point3D(planes[i].lon*SGD_DEGREES_TO_RADIANS,planes[i].lat*SGD_DEGREES_TO_RADIANS, 0.0 ),
608 planes[i].dist = distance/SG_NM_TO_METER;
609 planes[i].brg = 360.0-course*SGD_RADIANS_TO_DEGREES;
611 //cout << "Plane Id: " << planes[i].ident << " Distance to " << ident
612 // << " is " << planes[i].dist << " miles " << "Bearing " << planes[i].brg << endl;
617 // =======================================================================
618 // Add plane to Approach list
619 // =======================================================================
620 void FGApproach::AddPlane(string pid) {
623 for ( i=0; i<num_planes; i++) {
624 if ( planes[i].ident == pid) {
625 //cout << "Plane already registered: " << ident << " " << num_planes << endl;
629 planes[num_planes].ident = pid;
631 //cout << "Plane added to list: " << ident << " " << num_planes << endl;
635 // ================================================================================
636 // closest distance between a point (h1,d1) and a straigt line (h2,d2,h3) in 2 dim.
637 // ================================================================================
638 double FGApproach::calc_psl_dist(const double &h1, const double &d1,
639 const double &h2, const double &d2,
642 double a1 = h1 * SGD_DEGREES_TO_RADIANS;
643 double a2 = h2 * SGD_DEGREES_TO_RADIANS;
644 double a3 = h3 * SGD_DEGREES_TO_RADIANS;
645 double x1 = cos(a1) * d1;
646 double y1 = sin(a1) * d1;
647 double x2 = cos(a2) * d2;
648 double y2 = sin(a2) * d2;
652 // formula: dis = sqrt( (v1-v2)**2 - ((v1-v2)*v3)**2 ); vi = (xi,yi)
653 double val1 = (x1-x2)*(x1-x2) + (y1-y2)*(y1-y2);
654 double val2 = ((x1-x2)*x3 + (y1-y2)*y3) * ((x1-x2)*x3 + (y1-y2)*y3);
655 double dis = val1 - val2;
656 // now get sign for offset
657 //cout << x1 << " " << x2 << " " << y1 << " " << y2 << " "
658 // << x3 << " " << y3 << " "
659 // << val1 << " " << val2 << " " << dis << endl;
662 double da = fabs(atan2(y3,x3) - atan2(y1-y2,x1-x2));
663 if ( da > SGD_PI ) da -= 2*SGD_PI;
664 if ( fabs(da) > SGD_PI/2.) {
665 //if ( x3*(x1-x2) < 0.0 && y3*(y1-y2) < 0.0) {
669 //cout << x3 << " " << y3 << endl;
670 double dis1 = x1-x2-x3;
671 double dis2 = y1-y2-y3;
673 da = atan2(dis2,dis1);
674 if ( da < 0.0 ) da += 2*SGD_PI;
675 if ( da < a3 ) dis *= -1.0;
676 //cout << dis1 << " " << dis2 << " " << da*SGD_RADIANS_TO_DEGREES << " " << h3
677 // << " " << sqrt(dis1*dis1 + dis2*dis2) << " " << dis << endl;
678 //cout << atan2(dis2,dis1)*SGD_RADIANS_TO_DEGREES << " " << dis << endl;
684 // ========================================================================
685 // Calculate new bear/dist given starting bear/dis, and offset radial,
687 // ========================================================================
688 void FGApproach::calc_cd_head_dist(const double &h1, const double &d1,
689 const double &course, const double &dist,
690 double *h2, double *d2)
692 double a1 = h1 * SGD_DEGREES_TO_RADIANS;
693 double a2 = course * SGD_DEGREES_TO_RADIANS;
694 double x1 = cos(a1) * d1;
695 double y1 = sin(a1) * d1;
696 double x2 = cos(a2) * dist;
697 double y2 = sin(a2) * dist;
699 *d2 = sqrt((x1+x2)*(x1+x2) + (y1+y2)*(y1+y2));
700 *h2 = atan2( (y1+y2), (x1+x2) ) * SGD_RADIANS_TO_DEGREES;
701 if ( *h2 < 0 ) *h2 = *h2+360;
706 // ========================================================================
707 // get heading and distance between two points; point1 ---> point2
708 // ========================================================================
709 void FGApproach::calc_hd_course_dist(const double &h1, const double &d1,
710 const double &h2, const double &d2,
711 double *course, double *dist)
713 double a1 = h1 * SGD_DEGREES_TO_RADIANS;
714 double a2 = h2 * SGD_DEGREES_TO_RADIANS;
715 double x1 = cos(a1) * d1;
716 double y1 = sin(a1) * d1;
717 double x2 = cos(a2) * d2;
718 double y2 = sin(a2) * d2;
720 *dist = sqrt( (y2-y1)*(y2-y1) + (x2-x1)*(x2-x1) );
721 *course = atan2( (y2-y1), (x2-x1) ) * SGD_RADIANS_TO_DEGREES;
722 if ( *course < 0 ) *course = *course+360;
723 //cout << x1 << " " << y1 << " " << x2 << " " << y2 << " " << *dist << " " << *course << endl;
728 int FGApproach::RemovePlane() {
730 // first check if anything has to be done
731 bool rmplane = false;
734 for (i=0; i<num_planes; i++) {
735 if (planes[i].dist > range*SG_NM_TO_METER) {
740 if (!rmplane) return num_planes;
742 // now make a copy of the plane list
743 PlaneApp tmp[max_planes];
744 for (i=0; i<num_planes; i++) {
749 // now check which planes are still in range
750 for (i=0; i<num_planes; i++) {
751 if (tmp[i].dist <= range*SG_NM_TO_METER) {