1 // gps.cxx - distance-measuring equipment.
2 // Written by David Megginson, started 2003.
4 // This file is in the Public Domain and comes with no warranty.
10 #include <simgear/compiler.h>
11 #include <Aircraft/aircraft.hxx>
13 #include <simgear/route/route.hxx>
14 #include <simgear/math/sg_random.h>
15 #include <simgear/sg_inlines.h>
16 #include <Airports/simple.hxx>
18 #include <Main/fg_init.hxx>
19 #include <Main/globals.hxx>
20 #include <Main/fg_props.hxx>
21 #include <Main/util.hxx>
22 #include <Navaids/fixlist.hxx>
23 #include <Navaids/navlist.hxx>
30 GPS::GPS ( SGPropertyNode *node)
32 _last_longitude_deg(0),
33 _last_latitude_deg(0),
37 _wp0_longitude_deg(0),
40 _wp1_longitude_deg(0),
45 _name(node->getStringValue("name", "gps")),
46 _num(node->getIntValue("number", 0)),
59 delete route; // in case init is called twice
64 branch = "/instrumentation/" + _name;
66 SGPropertyNode *node = fgGetNode(branch.c_str(), _num, true );
68 _longitude_node = fgGetNode("/position/longitude-deg", true);
69 _latitude_node = fgGetNode("/position/latitude-deg", true);
70 _altitude_node = fgGetNode("/position/altitude-ft", true);
71 _magvar_node = fgGetNode("/environment/magnetic-variation-deg", true);
72 _serviceable_node = node->getChild("serviceable", 0, true);
73 _electrical_node = fgGetNode("/systems/electrical/outputs/gps", true);
75 SGPropertyNode *wp_node = node->getChild("wp", 0, true);
76 SGPropertyNode *wp0_node = wp_node->getChild("wp", 0, true);
77 SGPropertyNode *wp1_node = wp_node->getChild("wp", 1, true);
78 addWp = wp1_node->getChild("Add-to-route", 0, true);
80 _wp0_longitude_node = wp0_node->getChild("longitude-deg", 0, true);
81 _wp0_latitude_node = wp0_node->getChild("latitude-deg", 0, true);
82 _wp0_altitude_node = wp0_node->getChild("altitude-ft", 0, true);
83 _wp0_ID_node = wp0_node->getChild("ID", 0, true);
84 _wp0_name_node = wp0_node->getChild("name", 0, true);
85 _wp0_course_node = wp0_node->getChild("desired-course-deg", 0, true);
86 _wp0_waypoint_type_node = wp0_node->getChild("waypoint-type", 0, true);
87 _wp0_distance_node = wp0_node->getChild("distance-nm", 0, true);
88 _wp0_ttw_node = wp0_node->getChild("TTW", 0, true);
89 _wp0_bearing_node = wp0_node->getChild("bearing-true-deg", 0, true);
90 _wp0_mag_bearing_node = wp0_node->getChild("bearing-mag-deg", 0, true);
91 _wp0_course_deviation_node =
92 wp0_node->getChild("course-deviation-deg", 0, true);
93 _wp0_course_error_nm_node = wp0_node->getChild("course-error-nm", 0, true);
94 _wp0_to_flag_node = wp0_node->getChild("to-flag", 0, true);
95 _true_wp0_bearing_error_node =
96 wp0_node->getChild("true-bearing-error-deg", 0, true);
97 _magnetic_wp0_bearing_error_node =
98 wp0_node->getChild("magnetic-bearing-error-deg", 0, true);
100 _wp1_longitude_node = wp1_node->getChild("longitude-deg", 0, true);
101 _wp1_latitude_node = wp1_node->getChild("latitude-deg", 0, true);
102 _wp1_altitude_node = wp1_node->getChild("altitude-ft", 0, true);
103 _wp1_ID_node = wp1_node->getChild("ID", 0, true);
104 _wp1_name_node = wp1_node->getChild("name", 0, true);
105 _wp1_course_node = wp1_node->getChild("desired-course-deg", 0, true);
106 _wp1_waypoint_type_node = wp1_node->getChild("waypoint-type", 0, true);
107 _wp1_distance_node = wp1_node->getChild("distance-nm", 0, true);
108 _wp1_ttw_node = wp1_node->getChild("TTW", 0, true);
109 _wp1_bearing_node = wp1_node->getChild("bearing-true-deg", 0, true);
110 _wp1_mag_bearing_node = wp1_node->getChild("bearing-mag-deg", 0, true);
111 _wp1_course_deviation_node =
112 wp1_node->getChild("course-deviation-deg", 0, true);
113 _wp1_course_error_nm_node = wp1_node->getChild("course-error-nm", 0, true);
114 _wp1_to_flag_node = wp1_node->getChild("to-flag", 0, true);
115 _true_wp1_bearing_error_node =
116 wp1_node->getChild("true-bearing-error-deg", 0, true);
117 _magnetic_wp1_bearing_error_node =
118 wp1_node->getChild("magnetic-bearing-error-deg", 0, true);
119 _get_nearest_airport_node =
120 wp1_node->getChild("get-nearest-airport", 0, true);
122 _tracking_bug_node = node->getChild("tracking-bug", 0, true);
123 _raim_node = node->getChild("raim", 0, true);
125 _indicated_longitude_node =
126 node->getChild("indicated-longitude-deg", 0, true);
127 _indicated_latitude_node =
128 node->getChild("indicated-latitude-deg", 0, true);
129 _indicated_altitude_node =
130 node->getChild("indicated-altitude-ft", 0, true);
131 _indicated_vertical_speed_node =
132 node->getChild("indicated-vertical-speed", 0, true);
134 node->getChild("indicated-track-true-deg", 0, true);
135 _magnetic_track_node =
136 node->getChild("indicated-track-magnetic-deg", 0, true);
138 node->getChild("indicated-ground-speed-kt", 0, true);
140 node->getChild("odometer", 0, true);
141 _trip_odometer_node =
142 node->getChild("trip-odometer", 0, true);
143 _true_bug_error_node =
144 node->getChild("true-bug-error-deg", 0, true);
145 _magnetic_bug_error_node =
146 node->getChild("magnetic-bug-error-deg", 0, true);
149 wp_node->getChild("leg-distance-nm", 0, true);
151 wp_node->getChild("leg-true-course-deg", 0, true);
152 _leg_magnetic_course_node =
153 wp_node->getChild("leg-mag-course-deg", 0, true);
154 _alt_dist_ratio_node =
155 wp_node->getChild("alt-dist-ratio", 0, true);
156 _leg_course_deviation_node =
157 wp_node->getChild("leg-course-deviation-deg", 0, true);
158 _leg_course_error_nm_node =
159 wp_node->getChild("leg-course-error-nm", 0, true);
161 wp_node->getChild("leg-to-flag", 0, true);
162 _alt_deviation_node =
163 wp_node->getChild("alt-deviation-ft", 0, true);
165 _route = node->getChild("route", 0, true);
166 popWp = _route->getChild("Pop-WP", 0, true);
168 addWp->setBoolValue(false);
169 popWp->setBoolValue(false);
171 _serviceable_node->setBoolValue(true);
175 GPS::update (double delta_time_sec)
177 // If it's off, don't bother.
178 if (!_serviceable_node->getBoolValue() ||
179 !_electrical_node->getBoolValue()) {
181 _last_longitude_deg = 0;
182 _last_latitude_deg = 0;
183 _last_altitude_m = 0;
185 _raim_node->setDoubleValue(false);
186 _indicated_longitude_node->setDoubleValue(0);
187 _indicated_latitude_node->setDoubleValue(0);
188 _indicated_altitude_node->setDoubleValue(0);
189 _indicated_vertical_speed_node->setDoubleValue(0);
190 _true_track_node->setDoubleValue(0);
191 _magnetic_track_node->setDoubleValue(0);
192 _speed_node->setDoubleValue(0);
193 _wp1_distance_node->setDoubleValue(0);
194 _wp1_bearing_node->setDoubleValue(0);
195 _wp1_longitude_node->setDoubleValue(0);
196 _wp1_latitude_node->setDoubleValue(0);
197 _wp1_course_node->setDoubleValue(0);
198 _odometer_node->setDoubleValue(0);
199 _trip_odometer_node->setDoubleValue(0);
200 _tracking_bug_node->setDoubleValue(0);
201 _true_bug_error_node->setDoubleValue(0);
202 _magnetic_bug_error_node->setDoubleValue(0);
203 _true_wp1_bearing_error_node->setDoubleValue(0);
204 _magnetic_wp1_bearing_error_node->setDoubleValue(0);
208 // Get the aircraft position
209 // TODO: Add noise and other errors.
210 double longitude_deg = _longitude_node->getDoubleValue();
211 double latitude_deg = _latitude_node->getDoubleValue();
212 double altitude_m = _altitude_node->getDoubleValue() * SG_FEET_TO_METER;
213 double magvar_deg = _magvar_node->getDoubleValue();
217 // Bias and random error
218 double random_factor = sg_random();
219 double random_error = 1.4;
220 double error_radius = 5.1;
221 double bias_max_radius = 5.1;
222 double random_max_radius = 1.4;
224 bias_length += (random_factor-0.5) * 1.0e-3;
225 if (bias_length <= 0.0) bias_length = 0.0;
226 else if (bias_length >= bias_max_radius) bias_length = bias_max_radius;
227 bias_angle += (random_factor-0.5) * 1.0e-3;
228 if (bias_angle <= 0.0) bias_angle = 0.0;
229 else if (bias_angle >= 360.0) bias_angle = 360.0;
231 double random_length = random_factor * random_max_radius;
232 double random_angle = random_factor * 360.0;
234 double bias_x = bias_length * cos(bias_angle * SG_PI / 180.0);
235 double bias_y = bias_length * sin(bias_angle * SG_PI / 180.0);
236 double random_x = random_length * cos(random_angle * SG_PI / 180.0);
237 double random_y = random_length * sin(random_angle * SG_PI / 180.0);
238 double error_x = bias_x + random_x;
239 double error_y = bias_y + random_y;
240 double error_length = sqrt(error_x*error_x + error_y*error_y);
241 double error_angle = atan(error_y / error_x) * 180.0 / SG_PI;
246 geo_direct_wgs_84 ( altitude_m, latitude_deg,
247 longitude_deg, error_angle,
248 error_length, &lat2, &lon2,
250 //cout << lat2 << " " << lon2 << endl;
251 printf("%f %f \n", bias_length, bias_angle);
252 printf("%3.7f %3.7f \n", lat2, lon2);
253 printf("%f %f \n", error_length, error_angle);
259 double speed_kt, vertical_speed_mpm;
261 _raim_node->setBoolValue(true);
262 _indicated_longitude_node->setDoubleValue(longitude_deg);
263 _indicated_latitude_node->setDoubleValue(latitude_deg);
264 _indicated_altitude_node->setDoubleValue(altitude_m * SG_METER_TO_FEET);
267 double track1_deg, track2_deg, distance_m, odometer, mag_track_bearing;
268 geo_inverse_wgs_84(altitude_m,
269 _last_latitude_deg, _last_longitude_deg,
270 latitude_deg, longitude_deg,
271 &track1_deg, &track2_deg, &distance_m);
272 speed_kt = ((distance_m * SG_METER_TO_NM) *
273 ((1 / delta_time_sec) * 3600.0));
274 vertical_speed_mpm = ((altitude_m - _last_altitude_m) * 60 /
276 _indicated_vertical_speed_node->setDoubleValue
277 (vertical_speed_mpm * SG_METER_TO_FEET);
278 _true_track_node->setDoubleValue(track1_deg);
279 mag_track_bearing = track1_deg - magvar_deg;
280 SG_NORMALIZE_RANGE(mag_track_bearing, 0.0, 360.0);
281 _magnetic_track_node->setDoubleValue(mag_track_bearing);
282 speed_kt = fgGetLowPass(_last_speed_kts, speed_kt, delta_time_sec/20.0);
283 _last_speed_kts = speed_kt;
284 _speed_node->setDoubleValue(speed_kt);
286 odometer = _odometer_node->getDoubleValue();
287 _odometer_node->setDoubleValue(odometer + distance_m * SG_METER_TO_NM);
288 odometer = _trip_odometer_node->getDoubleValue();
289 _trip_odometer_node->setDoubleValue(odometer + distance_m * SG_METER_TO_NM);
291 // Get waypoint 0 position
292 double wp0_longitude_deg = _wp0_longitude_node->getDoubleValue();
293 double wp0_latitude_deg = _wp0_latitude_node->getDoubleValue();
294 double wp0_altitude_m = _wp0_altitude_node->getDoubleValue()
296 double wp0_course_deg = _wp0_course_node->getDoubleValue();
297 double wp0_distance, wp0_bearing_deg, wp0_course_deviation_deg,
298 wp0_course_error_m, wp0_TTW, wp0_bearing_error_deg;
299 string wp0_ID = _wp0_ID_node->getStringValue();
301 // Get waypoint 1 position
302 double wp1_longitude_deg = _wp1_longitude_node->getDoubleValue();
303 double wp1_latitude_deg = _wp1_latitude_node->getDoubleValue();
304 double wp1_altitude_m = _wp1_altitude_node->getDoubleValue()
306 double wp1_course_deg = _wp1_course_node->getDoubleValue();
307 double wp1_distance, wp1_bearing_deg, wp1_course_deviation_deg,
308 wp1_course_error_m, wp1_TTW, wp1_bearing_error_deg;
309 string wp1_ID = _wp1_ID_node->getStringValue();
311 // If the get-nearest-airport-node is true.
312 // Get the nearest airport, and set it as waypoint 1.
313 if (_get_nearest_airport_node->getBoolValue()) {
314 const FGAirport* a = globals->get_airports()->search(longitude_deg, latitude_deg);
316 _wp1_ID_node->setStringValue(a->getId().c_str());
317 wp1_longitude_deg = a->getLongitude();
318 wp1_latitude_deg = a->getLatitude();
319 _wp1_name_node->setStringValue(a->getName().c_str());
320 _get_nearest_airport_node->setBoolValue(false);
321 _last_wp1_ID = wp1_ID = a->getId().c_str();
325 // If the waypoint 0 ID has changed, try to find the new ID
326 // in the airport-, fix-, nav-database.
327 if ( !(_last_wp0_ID == wp0_ID) ) {
328 string waypont_type =
329 _wp0_waypoint_type_node->getStringValue();
330 if (waypont_type == "airport") {
331 const FGAirport* a = globals->get_airports()->search( wp0_ID );
333 wp0_longitude_deg = a->getLongitude();
334 wp0_latitude_deg = a->getLatitude();
335 _wp0_name_node->setStringValue(a->getName().c_str());
338 else if (waypont_type == "nav") {
340 = globals->get_navlist()->findByIdent(wp0_ID.c_str(),
344 //cout << "Nav found" << endl;
345 wp0_longitude_deg = n->get_lon();
346 wp0_latitude_deg = n->get_lat();
347 _wp0_name_node->setStringValue(n->get_name().c_str());
350 else if (waypont_type == "fix") {
352 if ( globals->get_fixlist()->query(wp0_ID, &f) ) {
353 //cout << "Fix found" << endl;
354 wp0_longitude_deg = f.get_lon();
355 wp0_latitude_deg = f.get_lat();
356 _wp0_name_node->setStringValue(wp0_ID.c_str());
359 _last_wp0_ID = wp0_ID;
362 // If the waypoint 1 ID has changed, try to find the new ID
363 // in the airport-, fix-, nav-database.
364 if ( !(_last_wp1_ID == wp1_ID) ) {
365 string waypont_type =
366 _wp1_waypoint_type_node->getStringValue();
367 if (waypont_type == "airport") {
368 const FGAirport* a = globals->get_airports()->search( wp1_ID );
370 wp1_longitude_deg = a->getLongitude();
371 wp1_latitude_deg = a->getLatitude();
372 _wp1_name_node->setStringValue(a->getName().c_str());
375 else if (waypont_type == "nav") {
377 = globals->get_navlist()->findByIdent(wp1_ID.c_str(),
381 //cout << "Nav found" << endl;
382 wp1_longitude_deg = n->get_lon();
383 wp1_latitude_deg = n->get_lat();
384 _wp1_name_node->setStringValue(n->get_name().c_str());
387 else if (waypont_type == "fix") {
389 if ( globals->get_fixlist()->query(wp1_ID, &f) ) {
390 //cout << "Fix found" << endl;
391 wp1_longitude_deg = f.get_lon();
392 wp1_latitude_deg = f.get_lat();
393 _wp1_name_node->setStringValue(wp1_ID.c_str());
396 _last_wp1_ID = wp1_ID;
401 // If any of the two waypoints have changed
402 // we need to calculate a new course between them,
403 // and values for vertical navigation.
404 if ( wp0_longitude_deg != _wp0_longitude_deg ||
405 wp0_latitude_deg != _wp0_latitude_deg ||
406 wp0_altitude_m != _wp0_altitude_m ||
407 wp1_longitude_deg != _wp1_longitude_deg ||
408 wp1_latitude_deg != _wp1_latitude_deg ||
409 wp1_altitude_m != _wp1_altitude_m )
411 // Update the global variables
412 _wp0_longitude_deg = wp0_longitude_deg;
413 _wp0_latitude_deg = wp0_latitude_deg;
414 _wp0_altitude_m = wp0_altitude_m;
415 _wp1_longitude_deg = wp1_longitude_deg;
416 _wp1_latitude_deg = wp1_latitude_deg;
417 _wp1_altitude_m = wp1_altitude_m;
419 // Get the course and distance from wp0 to wp1
420 SGWayPoint wp0(wp0_longitude_deg,
421 wp0_latitude_deg, wp0_altitude_m);
422 SGWayPoint wp1(wp1_longitude_deg,
423 wp1_latitude_deg, wp1_altitude_m);
425 wp1.CourseAndDistance(wp0, &_course_deg, &_distance_m);
426 double leg_mag_course = _course_deg - magvar_deg;
427 SG_NORMALIZE_RANGE(leg_mag_course, 0.0, 360.0);
429 // Get the altitude / distance ratio
430 if ( distance_m > 0.0 ) {
431 double alt_difference_m = wp0_altitude_m - wp1_altitude_m;
432 _alt_dist_ratio = alt_difference_m / _distance_m;
435 _leg_distance_node->setDoubleValue(_distance_m * SG_METER_TO_NM);
436 _leg_course_node->setDoubleValue(_course_deg);
437 _leg_magnetic_course_node->setDoubleValue(leg_mag_course);
438 _alt_dist_ratio_node->setDoubleValue(_alt_dist_ratio);
440 _wp0_longitude_node->setDoubleValue(wp0_longitude_deg);
441 _wp0_latitude_node->setDoubleValue(wp0_latitude_deg);
442 _wp1_longitude_node->setDoubleValue(wp1_longitude_deg);
443 _wp1_latitude_node->setDoubleValue(wp1_latitude_deg);
447 // Find the bearing and distance to waypoint 0.
448 SGWayPoint wp0(wp0_longitude_deg, wp0_latitude_deg, wp0_altitude_m);
449 wp0.CourseAndDistance(longitude_deg, latitude_deg, altitude_m,
450 &wp0_bearing_deg, &wp0_distance);
451 _wp0_distance_node->setDoubleValue(wp0_distance * SG_METER_TO_NM);
452 _wp0_bearing_node->setDoubleValue(wp0_bearing_deg);
453 double wp0_mag_bearing_deg = wp0_bearing_deg - magvar_deg;
454 SG_NORMALIZE_RANGE(wp0_mag_bearing_deg, 0.0, 360.0);
455 _wp0_mag_bearing_node->setDoubleValue(wp0_mag_bearing_deg);
456 wp0_bearing_error_deg = track1_deg - wp0_bearing_deg;
457 SG_NORMALIZE_RANGE(wp0_bearing_error_deg, -180.0, 180.0);
458 _true_wp0_bearing_error_node->setDoubleValue(wp0_bearing_error_deg);
460 // Estimate time to waypoint 0.
461 // The estimation does not take track into consideration,
462 // so if you are going away from the waypoint the TTW will
463 // increase. Makes most sense when travelling directly towards
465 if (speed_kt > 0.0 && wp0_distance > 0.0) {
466 wp0_TTW = (wp0_distance * SG_METER_TO_NM) / (speed_kt / 3600);
471 unsigned int wp0_TTW_seconds = (int) (wp0_TTW + 0.5);
472 if (wp0_TTW_seconds < 356400) { // That's 99 hours
473 unsigned int wp0_TTW_minutes = 0;
474 unsigned int wp0_TTW_hours = 0;
476 while (wp0_TTW_seconds >= 3600) {
477 wp0_TTW_seconds -= 3600;
480 while (wp0_TTW_seconds >= 60) {
481 wp0_TTW_seconds -= 60;
484 snprintf(wp0_TTW_str, 9, "%02d:%02d:%02d",
485 wp0_TTW_hours, wp0_TTW_minutes, wp0_TTW_seconds);
486 _wp0_ttw_node->setStringValue(wp0_TTW_str);
489 _wp0_ttw_node->setStringValue("--:--:--");
491 // Course deviation is the diffenrence between the bearing
493 wp0_course_deviation_deg = wp0_bearing_deg -
495 SG_NORMALIZE_RANGE(wp0_course_deviation_deg, -180.0, 180.0);
497 // If the course deviation is less than 90 degrees to either side,
498 // our desired course is towards the waypoint.
499 // It does not matter if we are actually moving
500 // towards or from the waypoint.
501 if (fabs(wp0_course_deviation_deg) < 90.0) {
502 _wp0_to_flag_node->setBoolValue(true); }
503 // If it's more than 90 degrees the desired
504 // course is from the waypoint.
505 else if (fabs(wp0_course_deviation_deg) > 90.0) {
506 _wp0_to_flag_node->setBoolValue(false);
507 // When the course is away from the waypoint,
508 // it makes sense to change the sign of the deviation.
509 wp0_course_deviation_deg *= -1.0;
510 SG_NORMALIZE_RANGE(wp0_course_deviation_deg, -90.0, 90.0);
513 _wp0_course_deviation_node->setDoubleValue(wp0_course_deviation_deg);
515 // Cross track error.
516 wp0_course_error_m = sin(wp0_course_deviation_deg * SG_PI / 180.0)
518 _wp0_course_error_nm_node->setDoubleValue(wp0_course_error_m
523 // Find the bearing and distance to waypoint 1.
524 SGWayPoint wp1(wp1_longitude_deg, wp1_latitude_deg, wp1_altitude_m);
525 wp1.CourseAndDistance(longitude_deg, latitude_deg, altitude_m,
526 &wp1_bearing_deg, &wp1_distance);
527 _wp1_distance_node->setDoubleValue(wp1_distance * SG_METER_TO_NM);
528 _wp1_bearing_node->setDoubleValue(wp1_bearing_deg);
529 double wp1_mag_bearing_deg = wp1_bearing_deg - magvar_deg;
530 SG_NORMALIZE_RANGE(wp1_mag_bearing_deg, 0.0, 360.0);
531 _wp1_mag_bearing_node->setDoubleValue(wp1_mag_bearing_deg);
532 wp1_bearing_error_deg = track1_deg - wp1_bearing_deg;
533 SG_NORMALIZE_RANGE(wp1_bearing_error_deg, -180.0, 180.0);
534 _true_wp1_bearing_error_node->setDoubleValue(wp1_bearing_error_deg);
536 // Estimate time to waypoint 1.
537 // The estimation does not take track into consideration,
538 // so if you are going away from the waypoint the TTW will
539 // increase. Makes most sense when travelling directly towards
541 if (speed_kt > 0.0 && wp1_distance > 0.0) {
542 wp1_TTW = (wp1_distance * SG_METER_TO_NM) / (speed_kt / 3600);
547 unsigned int wp1_TTW_seconds = (int) (wp1_TTW + 0.5);
548 if (wp1_TTW_seconds < 356400) { // That's 99 hours
549 unsigned int wp1_TTW_minutes = 0;
550 unsigned int wp1_TTW_hours = 0;
552 while (wp1_TTW_seconds >= 3600) {
553 wp1_TTW_seconds -= 3600;
556 while (wp1_TTW_seconds >= 60) {
557 wp1_TTW_seconds -= 60;
560 snprintf(wp1_TTW_str, 9, "%02d:%02d:%02d",
561 wp1_TTW_hours, wp1_TTW_minutes, wp1_TTW_seconds);
562 _wp1_ttw_node->setStringValue(wp1_TTW_str);
565 _wp1_ttw_node->setStringValue("--:--:--");
567 // Course deviation is the diffenrence between the bearing
569 wp1_course_deviation_deg = wp1_bearing_deg - wp1_course_deg;
570 SG_NORMALIZE_RANGE(wp1_course_deviation_deg, -180.0, 180.0);
572 // If the course deviation is less than 90 degrees to either side,
573 // our desired course is towards the waypoint.
574 // It does not matter if we are actually moving
575 // towards or from the waypoint.
576 if (fabs(wp1_course_deviation_deg) < 90.0) {
577 _wp1_to_flag_node->setBoolValue(true); }
578 // If it's more than 90 degrees the desired
579 // course is from the waypoint.
580 else if (fabs(wp1_course_deviation_deg) > 90.0) {
581 _wp1_to_flag_node->setBoolValue(false);
582 // When the course is away from the waypoint,
583 // it makes sense to change the sign of the deviation.
584 wp1_course_deviation_deg *= -1.0;
585 SG_NORMALIZE_RANGE(wp1_course_deviation_deg, -90.0, 90.0);
588 _wp1_course_deviation_node->setDoubleValue(wp1_course_deviation_deg);
590 // Cross track error.
591 wp1_course_error_m = sin(wp1_course_deviation_deg * SG_PI / 180.0)
593 _wp1_course_error_nm_node->setDoubleValue(wp1_course_error_m
597 // Leg course deviation is the diffenrence between the bearing
599 double course_deviation_deg = wp1_bearing_deg - _course_deg;
600 SG_NORMALIZE_RANGE(course_deviation_deg, -180.0, 180.0);
602 // If the course deviation is less than 90 degrees to either side,
603 // our desired course is towards the waypoint.
604 // It does not matter if we are actually moving
605 // towards or from the waypoint.
606 if (fabs(course_deviation_deg) < 90.0) {
607 _leg_to_flag_node->setBoolValue(true); }
608 // If it's more than 90 degrees the desired
609 // course is from the waypoint.
610 else if (fabs(course_deviation_deg) > 90.0) {
611 _leg_to_flag_node->setBoolValue(false);
612 // When the course is away from the waypoint,
613 // it makes sense to change the sign of the deviation.
614 course_deviation_deg *= -1.0;
615 SG_NORMALIZE_RANGE(course_deviation_deg, -90.0, 90.0);
618 _leg_course_deviation_node->setDoubleValue(course_deviation_deg);
620 // Cross track error.
621 double course_error_m = sin(course_deviation_deg * SG_PI / 180.0)
623 _leg_course_error_nm_node->setDoubleValue(course_error_m * SG_METER_TO_NM);
625 // Altitude deviation
626 double desired_altitude_m = wp1_altitude_m
627 + wp1_distance * _alt_dist_ratio;
628 double altitude_deviation_m = altitude_m - desired_altitude_m;
629 _alt_deviation_node->setDoubleValue(altitude_deviation_m * SG_METER_TO_FEET);
634 double tracking_bug = _tracking_bug_node->getDoubleValue();
635 double true_bug_error = tracking_bug - track1_deg;
636 double magnetic_bug_error = tracking_bug - mag_track_bearing;
638 // Get the errors into the (-180,180) range.
639 SG_NORMALIZE_RANGE(true_bug_error, -180.0, 180.0);
640 SG_NORMALIZE_RANGE(magnetic_bug_error, -180.0, 180.0);
642 _true_bug_error_node->setDoubleValue(true_bug_error);
643 _magnetic_bug_error_node->setDoubleValue(magnetic_bug_error);
646 // Add WP 1 to the route.
647 if ( addWp->getBoolValue() )
649 addWp->setBoolValue(false);
651 SGWayPoint tempWp( _wp1_longitude_node->getDoubleValue(),
652 _wp1_latitude_node->getDoubleValue(),
653 _wp1_altitude_node->getDoubleValue(),
655 _wp1_ID_node->getStringValue(),
656 _wp1_name_node->getStringValue() );
658 route->add_waypoint(tempWp);
661 _route->getChild("Waypoint", route->size()-1, true);
662 SGPropertyNode *id = wp->getChild("ID", 0, true);
663 SGPropertyNode *name = wp->getChild("Name", 0, true);
664 SGPropertyNode *lat = wp->getChild("Latitude", 0, true);
665 SGPropertyNode *lon = wp->getChild("Longitude", 0, true);
666 SGPropertyNode *alt = wp->getChild("Altitude", 0, true);
668 id->setStringValue( tempWp.get_id().c_str() );
669 name->setStringValue( tempWp.get_name().c_str() );
670 lat->setDoubleValue( tempWp.get_target_lat() );
671 lon->setDoubleValue( tempWp.get_target_lon() );
672 alt->setDoubleValue( tempWp.get_target_alt() );
675 if ( popWp->getBoolValue() )
677 popWp->setBoolValue(false);
679 route->delete_first();
680 _route->removeChild("Waypoint", 0, false);
684 _true_track_node->setDoubleValue(0.0);
685 _magnetic_track_node->setDoubleValue(0.0);
686 _speed_node->setDoubleValue(0.0);
690 _last_longitude_deg = longitude_deg;
691 _last_latitude_deg = latitude_deg;
692 _last_altitude_m = altitude_m;