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 <simgear/math/sg_geodesy.hxx>
18 #include <Airports/simple.hxx>
20 #include <Main/fg_init.hxx>
21 #include <Main/globals.hxx>
22 #include <Main/fg_props.hxx>
23 #include <Main/util.hxx>
24 #include <Navaids/fixlist.hxx>
25 #include <Navaids/navlist.hxx>
32 GPS::GPS ( SGPropertyNode *node)
34 _last_longitude_deg(0),
35 _last_latitude_deg(0),
39 _wp0_longitude_deg(0),
42 _wp1_longitude_deg(0),
47 _name(node->getStringValue("name", "gps")),
48 _num(node->getIntValue("number", 0)),
61 delete route; // in case init is called twice
66 branch = "/instrumentation/" + _name;
68 SGPropertyNode *node = fgGetNode(branch.c_str(), _num, true );
70 _longitude_node = fgGetNode("/position/longitude-deg", true);
71 _latitude_node = fgGetNode("/position/latitude-deg", true);
72 _altitude_node = fgGetNode("/position/altitude-ft", true);
73 _magvar_node = fgGetNode("/environment/magnetic-variation-deg", true);
74 _serviceable_node = node->getChild("serviceable", 0, true);
75 _electrical_node = fgGetNode("/systems/electrical/outputs/gps", true);
77 SGPropertyNode *wp_node = node->getChild("wp", 0, true);
78 SGPropertyNode *wp0_node = wp_node->getChild("wp", 0, true);
79 SGPropertyNode *wp1_node = wp_node->getChild("wp", 1, true);
80 addWp = wp1_node->getChild("Add-to-route", 0, true);
82 _wp0_longitude_node = wp0_node->getChild("longitude-deg", 0, true);
83 _wp0_latitude_node = wp0_node->getChild("latitude-deg", 0, true);
84 _wp0_altitude_node = wp0_node->getChild("altitude-ft", 0, true);
85 _wp0_ID_node = wp0_node->getChild("ID", 0, true);
86 _wp0_name_node = wp0_node->getChild("name", 0, true);
87 _wp0_course_node = wp0_node->getChild("desired-course-deg", 0, true);
88 _wp0_waypoint_type_node = wp0_node->getChild("waypoint-type", 0, true);
89 _wp0_distance_node = wp0_node->getChild("distance-nm", 0, true);
90 _wp0_ttw_node = wp0_node->getChild("TTW", 0, true);
91 _wp0_bearing_node = wp0_node->getChild("bearing-true-deg", 0, true);
92 _wp0_mag_bearing_node = wp0_node->getChild("bearing-mag-deg", 0, true);
93 _wp0_course_deviation_node =
94 wp0_node->getChild("course-deviation-deg", 0, true);
95 _wp0_course_error_nm_node = wp0_node->getChild("course-error-nm", 0, true);
96 _wp0_to_flag_node = wp0_node->getChild("to-flag", 0, true);
97 _true_wp0_bearing_error_node =
98 wp0_node->getChild("true-bearing-error-deg", 0, true);
99 _magnetic_wp0_bearing_error_node =
100 wp0_node->getChild("magnetic-bearing-error-deg", 0, true);
102 _wp1_longitude_node = wp1_node->getChild("longitude-deg", 0, true);
103 _wp1_latitude_node = wp1_node->getChild("latitude-deg", 0, true);
104 _wp1_altitude_node = wp1_node->getChild("altitude-ft", 0, true);
105 _wp1_ID_node = wp1_node->getChild("ID", 0, true);
106 _wp1_name_node = wp1_node->getChild("name", 0, true);
107 _wp1_course_node = wp1_node->getChild("desired-course-deg", 0, true);
108 _wp1_waypoint_type_node = wp1_node->getChild("waypoint-type", 0, true);
109 _wp1_distance_node = wp1_node->getChild("distance-nm", 0, true);
110 _wp1_ttw_node = wp1_node->getChild("TTW", 0, true);
111 _wp1_bearing_node = wp1_node->getChild("bearing-true-deg", 0, true);
112 _wp1_mag_bearing_node = wp1_node->getChild("bearing-mag-deg", 0, true);
113 _wp1_course_deviation_node =
114 wp1_node->getChild("course-deviation-deg", 0, true);
115 _wp1_course_error_nm_node = wp1_node->getChild("course-error-nm", 0, true);
116 _wp1_to_flag_node = wp1_node->getChild("to-flag", 0, true);
117 _true_wp1_bearing_error_node =
118 wp1_node->getChild("true-bearing-error-deg", 0, true);
119 _magnetic_wp1_bearing_error_node =
120 wp1_node->getChild("magnetic-bearing-error-deg", 0, true);
121 _get_nearest_airport_node =
122 wp1_node->getChild("get-nearest-airport", 0, true);
124 _tracking_bug_node = node->getChild("tracking-bug", 0, true);
125 _raim_node = node->getChild("raim", 0, true);
127 _indicated_longitude_node =
128 node->getChild("indicated-longitude-deg", 0, true);
129 _indicated_latitude_node =
130 node->getChild("indicated-latitude-deg", 0, true);
131 _indicated_altitude_node =
132 node->getChild("indicated-altitude-ft", 0, true);
133 _indicated_vertical_speed_node =
134 node->getChild("indicated-vertical-speed", 0, true);
136 node->getChild("indicated-track-true-deg", 0, true);
137 _magnetic_track_node =
138 node->getChild("indicated-track-magnetic-deg", 0, true);
140 node->getChild("indicated-ground-speed-kt", 0, true);
142 node->getChild("odometer", 0, true);
143 _trip_odometer_node =
144 node->getChild("trip-odometer", 0, true);
145 _true_bug_error_node =
146 node->getChild("true-bug-error-deg", 0, true);
147 _magnetic_bug_error_node =
148 node->getChild("magnetic-bug-error-deg", 0, true);
151 wp_node->getChild("leg-distance-nm", 0, true);
153 wp_node->getChild("leg-true-course-deg", 0, true);
154 _leg_magnetic_course_node =
155 wp_node->getChild("leg-mag-course-deg", 0, true);
156 _alt_dist_ratio_node =
157 wp_node->getChild("alt-dist-ratio", 0, true);
158 _leg_course_deviation_node =
159 wp_node->getChild("leg-course-deviation-deg", 0, true);
160 _leg_course_error_nm_node =
161 wp_node->getChild("leg-course-error-nm", 0, true);
163 wp_node->getChild("leg-to-flag", 0, true);
164 _alt_deviation_node =
165 wp_node->getChild("alt-deviation-ft", 0, true);
167 _route = node->getChild("route", 0, true);
168 popWp = _route->getChild("Pop-WP", 0, true);
170 addWp->setBoolValue(false);
171 popWp->setBoolValue(false);
173 _serviceable_node->setBoolValue(true);
177 GPS::update (double delta_time_sec)
179 // If it's off, don't bother.
180 if (!_serviceable_node->getBoolValue() ||
181 !_electrical_node->getBoolValue()) {
183 _last_longitude_deg = 0;
184 _last_latitude_deg = 0;
185 _last_altitude_m = 0;
187 _raim_node->setDoubleValue(false);
188 _indicated_longitude_node->setDoubleValue(0);
189 _indicated_latitude_node->setDoubleValue(0);
190 _indicated_altitude_node->setDoubleValue(0);
191 _indicated_vertical_speed_node->setDoubleValue(0);
192 _true_track_node->setDoubleValue(0);
193 _magnetic_track_node->setDoubleValue(0);
194 _speed_node->setDoubleValue(0);
195 _wp1_distance_node->setDoubleValue(0);
196 _wp1_bearing_node->setDoubleValue(0);
197 _wp1_longitude_node->setDoubleValue(0);
198 _wp1_latitude_node->setDoubleValue(0);
199 _wp1_course_node->setDoubleValue(0);
200 _odometer_node->setDoubleValue(0);
201 _trip_odometer_node->setDoubleValue(0);
202 _tracking_bug_node->setDoubleValue(0);
203 _true_bug_error_node->setDoubleValue(0);
204 _magnetic_bug_error_node->setDoubleValue(0);
205 _true_wp1_bearing_error_node->setDoubleValue(0);
206 _magnetic_wp1_bearing_error_node->setDoubleValue(0);
210 // Get the aircraft position
211 // TODO: Add noise and other errors.
212 double longitude_deg = _longitude_node->getDoubleValue();
213 double latitude_deg = _latitude_node->getDoubleValue();
214 double altitude_m = _altitude_node->getDoubleValue() * SG_FEET_TO_METER;
215 double magvar_deg = _magvar_node->getDoubleValue();
219 // Bias and random error
220 double random_factor = sg_random();
221 double random_error = 1.4;
222 double error_radius = 5.1;
223 double bias_max_radius = 5.1;
224 double random_max_radius = 1.4;
226 bias_length += (random_factor-0.5) * 1.0e-3;
227 if (bias_length <= 0.0) bias_length = 0.0;
228 else if (bias_length >= bias_max_radius) bias_length = bias_max_radius;
229 bias_angle += (random_factor-0.5) * 1.0e-3;
230 if (bias_angle <= 0.0) bias_angle = 0.0;
231 else if (bias_angle >= 360.0) bias_angle = 360.0;
233 double random_length = random_factor * random_max_radius;
234 double random_angle = random_factor * 360.0;
236 double bias_x = bias_length * cos(bias_angle * SG_PI / 180.0);
237 double bias_y = bias_length * sin(bias_angle * SG_PI / 180.0);
238 double random_x = random_length * cos(random_angle * SG_PI / 180.0);
239 double random_y = random_length * sin(random_angle * SG_PI / 180.0);
240 double error_x = bias_x + random_x;
241 double error_y = bias_y + random_y;
242 double error_length = sqrt(error_x*error_x + error_y*error_y);
243 double error_angle = atan(error_y / error_x) * 180.0 / SG_PI;
248 geo_direct_wgs_84 ( altitude_m, latitude_deg,
249 longitude_deg, error_angle,
250 error_length, &lat2, &lon2,
252 //cout << lat2 << " " << lon2 << endl;
253 printf("%f %f \n", bias_length, bias_angle);
254 printf("%3.7f %3.7f \n", lat2, lon2);
255 printf("%f %f \n", error_length, error_angle);
261 double speed_kt, vertical_speed_mpm;
263 _raim_node->setBoolValue(true);
264 _indicated_longitude_node->setDoubleValue(longitude_deg);
265 _indicated_latitude_node->setDoubleValue(latitude_deg);
266 _indicated_altitude_node->setDoubleValue(altitude_m * SG_METER_TO_FEET);
269 double track1_deg, track2_deg, distance_m, odometer, mag_track_bearing;
270 geo_inverse_wgs_84(altitude_m,
271 _last_latitude_deg, _last_longitude_deg,
272 latitude_deg, longitude_deg,
273 &track1_deg, &track2_deg, &distance_m);
274 speed_kt = ((distance_m * SG_METER_TO_NM) *
275 ((1 / delta_time_sec) * 3600.0));
276 vertical_speed_mpm = ((altitude_m - _last_altitude_m) * 60 /
278 _indicated_vertical_speed_node->setDoubleValue
279 (vertical_speed_mpm * SG_METER_TO_FEET);
280 _true_track_node->setDoubleValue(track1_deg);
281 mag_track_bearing = track1_deg - magvar_deg;
282 SG_NORMALIZE_RANGE(mag_track_bearing, 0.0, 360.0);
283 _magnetic_track_node->setDoubleValue(mag_track_bearing);
284 speed_kt = fgGetLowPass(_last_speed_kts, speed_kt, delta_time_sec/20.0);
285 _last_speed_kts = speed_kt;
286 _speed_node->setDoubleValue(speed_kt);
288 odometer = _odometer_node->getDoubleValue();
289 _odometer_node->setDoubleValue(odometer + distance_m * SG_METER_TO_NM);
290 odometer = _trip_odometer_node->getDoubleValue();
291 _trip_odometer_node->setDoubleValue(odometer + distance_m * SG_METER_TO_NM);
293 // Get waypoint 0 position
294 double wp0_longitude_deg = _wp0_longitude_node->getDoubleValue();
295 double wp0_latitude_deg = _wp0_latitude_node->getDoubleValue();
296 double wp0_altitude_m = _wp0_altitude_node->getDoubleValue()
298 double wp0_course_deg = _wp0_course_node->getDoubleValue();
299 double wp0_distance, wp0_bearing_deg, wp0_course_deviation_deg,
300 wp0_course_error_m, wp0_TTW, wp0_bearing_error_deg;
301 string wp0_ID = _wp0_ID_node->getStringValue();
303 // Get waypoint 1 position
304 double wp1_longitude_deg = _wp1_longitude_node->getDoubleValue();
305 double wp1_latitude_deg = _wp1_latitude_node->getDoubleValue();
306 double wp1_altitude_m = _wp1_altitude_node->getDoubleValue()
308 double wp1_course_deg = _wp1_course_node->getDoubleValue();
309 double wp1_distance, wp1_bearing_deg, wp1_course_deviation_deg,
310 wp1_course_error_m, wp1_TTW, wp1_bearing_error_deg;
311 string wp1_ID = _wp1_ID_node->getStringValue();
313 // If the get-nearest-airport-node is true.
314 // Get the nearest airport, and set it as waypoint 1.
315 if (_get_nearest_airport_node->getBoolValue()) {
316 const FGAirport* a = globals->get_airports()->search(longitude_deg, latitude_deg);
318 _wp1_ID_node->setStringValue(a->getId().c_str());
319 wp1_longitude_deg = a->getLongitude();
320 wp1_latitude_deg = a->getLatitude();
321 _wp1_name_node->setStringValue(a->getName().c_str());
322 _get_nearest_airport_node->setBoolValue(false);
323 _last_wp1_ID = wp1_ID = a->getId().c_str();
327 // If the waypoint 0 ID has changed, try to find the new ID
328 // in the airport-, fix-, nav-database.
329 if ( !(_last_wp0_ID == wp0_ID) ) {
330 string waypont_type =
331 _wp0_waypoint_type_node->getStringValue();
332 if (waypont_type == "airport") {
333 const FGAirport* a = globals->get_airports()->search( wp0_ID );
335 wp0_longitude_deg = a->getLongitude();
336 wp0_latitude_deg = a->getLatitude();
337 _wp0_name_node->setStringValue(a->getName().c_str());
340 else if (waypont_type == "nav") {
342 = globals->get_navlist()->findByIdent(wp0_ID.c_str(),
346 //cout << "Nav found" << endl;
347 wp0_longitude_deg = n->get_lon();
348 wp0_latitude_deg = n->get_lat();
349 _wp0_name_node->setStringValue(n->get_name().c_str());
352 else if (waypont_type == "fix") {
354 if ( globals->get_fixlist()->query(wp0_ID, &f) ) {
355 //cout << "Fix found" << endl;
356 wp0_longitude_deg = f.get_lon();
357 wp0_latitude_deg = f.get_lat();
358 _wp0_name_node->setStringValue(wp0_ID.c_str());
361 _last_wp0_ID = wp0_ID;
364 // If the waypoint 1 ID has changed, try to find the new ID
365 // in the airport-, fix-, nav-database.
366 if ( !(_last_wp1_ID == wp1_ID) ) {
367 string waypont_type =
368 _wp1_waypoint_type_node->getStringValue();
369 if (waypont_type == "airport") {
370 const FGAirport* a = globals->get_airports()->search( wp1_ID );
372 wp1_longitude_deg = a->getLongitude();
373 wp1_latitude_deg = a->getLatitude();
374 _wp1_name_node->setStringValue(a->getName().c_str());
377 else if (waypont_type == "nav") {
379 = globals->get_navlist()->findByIdent(wp1_ID.c_str(),
383 //cout << "Nav found" << endl;
384 wp1_longitude_deg = n->get_lon();
385 wp1_latitude_deg = n->get_lat();
386 _wp1_name_node->setStringValue(n->get_name().c_str());
389 else if (waypont_type == "fix") {
391 if ( globals->get_fixlist()->query(wp1_ID, &f) ) {
392 //cout << "Fix found" << endl;
393 wp1_longitude_deg = f.get_lon();
394 wp1_latitude_deg = f.get_lat();
395 _wp1_name_node->setStringValue(wp1_ID.c_str());
398 _last_wp1_ID = wp1_ID;
403 // If any of the two waypoints have changed
404 // we need to calculate a new course between them,
405 // and values for vertical navigation.
406 if ( wp0_longitude_deg != _wp0_longitude_deg ||
407 wp0_latitude_deg != _wp0_latitude_deg ||
408 wp0_altitude_m != _wp0_altitude_m ||
409 wp1_longitude_deg != _wp1_longitude_deg ||
410 wp1_latitude_deg != _wp1_latitude_deg ||
411 wp1_altitude_m != _wp1_altitude_m )
413 // Update the global variables
414 _wp0_longitude_deg = wp0_longitude_deg;
415 _wp0_latitude_deg = wp0_latitude_deg;
416 _wp0_altitude_m = wp0_altitude_m;
417 _wp1_longitude_deg = wp1_longitude_deg;
418 _wp1_latitude_deg = wp1_latitude_deg;
419 _wp1_altitude_m = wp1_altitude_m;
421 // Get the course and distance from wp0 to wp1
422 SGWayPoint wp0(wp0_longitude_deg,
423 wp0_latitude_deg, wp0_altitude_m);
424 SGWayPoint wp1(wp1_longitude_deg,
425 wp1_latitude_deg, wp1_altitude_m);
427 wp1.CourseAndDistance(wp0, &_course_deg, &_distance_m);
428 double leg_mag_course = _course_deg - magvar_deg;
429 SG_NORMALIZE_RANGE(leg_mag_course, 0.0, 360.0);
431 // Get the altitude / distance ratio
432 if ( distance_m > 0.0 ) {
433 double alt_difference_m = wp0_altitude_m - wp1_altitude_m;
434 _alt_dist_ratio = alt_difference_m / _distance_m;
437 _leg_distance_node->setDoubleValue(_distance_m * SG_METER_TO_NM);
438 _leg_course_node->setDoubleValue(_course_deg);
439 _leg_magnetic_course_node->setDoubleValue(leg_mag_course);
440 _alt_dist_ratio_node->setDoubleValue(_alt_dist_ratio);
442 _wp0_longitude_node->setDoubleValue(wp0_longitude_deg);
443 _wp0_latitude_node->setDoubleValue(wp0_latitude_deg);
444 _wp1_longitude_node->setDoubleValue(wp1_longitude_deg);
445 _wp1_latitude_node->setDoubleValue(wp1_latitude_deg);
449 // Find the bearing and distance to waypoint 0.
450 SGWayPoint wp0(wp0_longitude_deg, wp0_latitude_deg, wp0_altitude_m);
451 wp0.CourseAndDistance(longitude_deg, latitude_deg, altitude_m,
452 &wp0_bearing_deg, &wp0_distance);
453 _wp0_distance_node->setDoubleValue(wp0_distance * SG_METER_TO_NM);
454 _wp0_bearing_node->setDoubleValue(wp0_bearing_deg);
455 double wp0_mag_bearing_deg = wp0_bearing_deg - magvar_deg;
456 SG_NORMALIZE_RANGE(wp0_mag_bearing_deg, 0.0, 360.0);
457 _wp0_mag_bearing_node->setDoubleValue(wp0_mag_bearing_deg);
458 wp0_bearing_error_deg = track1_deg - wp0_bearing_deg;
459 SG_NORMALIZE_RANGE(wp0_bearing_error_deg, -180.0, 180.0);
460 _true_wp0_bearing_error_node->setDoubleValue(wp0_bearing_error_deg);
462 // Estimate time to waypoint 0.
463 // The estimation does not take track into consideration,
464 // so if you are going away from the waypoint the TTW will
465 // increase. Makes most sense when travelling directly towards
467 if (speed_kt > 0.0 && wp0_distance > 0.0) {
468 wp0_TTW = (wp0_distance * SG_METER_TO_NM) / (speed_kt / 3600);
473 unsigned int wp0_TTW_seconds = (int) (wp0_TTW + 0.5);
474 if (wp0_TTW_seconds < 356400) { // That's 99 hours
475 unsigned int wp0_TTW_minutes = 0;
476 unsigned int wp0_TTW_hours = 0;
478 while (wp0_TTW_seconds >= 3600) {
479 wp0_TTW_seconds -= 3600;
482 while (wp0_TTW_seconds >= 60) {
483 wp0_TTW_seconds -= 60;
486 snprintf(wp0_TTW_str, 9, "%02d:%02d:%02d",
487 wp0_TTW_hours, wp0_TTW_minutes, wp0_TTW_seconds);
488 _wp0_ttw_node->setStringValue(wp0_TTW_str);
491 _wp0_ttw_node->setStringValue("--:--:--");
493 // Course deviation is the diffenrence between the bearing
495 wp0_course_deviation_deg = wp0_bearing_deg -
497 SG_NORMALIZE_RANGE(wp0_course_deviation_deg, -180.0, 180.0);
499 // If the course deviation is less than 90 degrees to either side,
500 // our desired course is towards the waypoint.
501 // It does not matter if we are actually moving
502 // towards or from the waypoint.
503 if (fabs(wp0_course_deviation_deg) < 90.0) {
504 _wp0_to_flag_node->setBoolValue(true); }
505 // If it's more than 90 degrees the desired
506 // course is from the waypoint.
507 else if (fabs(wp0_course_deviation_deg) > 90.0) {
508 _wp0_to_flag_node->setBoolValue(false);
509 // When the course is away from the waypoint,
510 // it makes sense to change the sign of the deviation.
511 wp0_course_deviation_deg *= -1.0;
512 SG_NORMALIZE_RANGE(wp0_course_deviation_deg, -90.0, 90.0);
515 _wp0_course_deviation_node->setDoubleValue(wp0_course_deviation_deg);
517 // Cross track error.
518 wp0_course_error_m = sin(wp0_course_deviation_deg * SG_PI / 180.0)
520 _wp0_course_error_nm_node->setDoubleValue(wp0_course_error_m
525 // Find the bearing and distance to waypoint 1.
526 SGWayPoint wp1(wp1_longitude_deg, wp1_latitude_deg, wp1_altitude_m);
527 wp1.CourseAndDistance(longitude_deg, latitude_deg, altitude_m,
528 &wp1_bearing_deg, &wp1_distance);
529 _wp1_distance_node->setDoubleValue(wp1_distance * SG_METER_TO_NM);
530 _wp1_bearing_node->setDoubleValue(wp1_bearing_deg);
531 double wp1_mag_bearing_deg = wp1_bearing_deg - magvar_deg;
532 SG_NORMALIZE_RANGE(wp1_mag_bearing_deg, 0.0, 360.0);
533 _wp1_mag_bearing_node->setDoubleValue(wp1_mag_bearing_deg);
534 wp1_bearing_error_deg = track1_deg - wp1_bearing_deg;
535 SG_NORMALIZE_RANGE(wp1_bearing_error_deg, -180.0, 180.0);
536 _true_wp1_bearing_error_node->setDoubleValue(wp1_bearing_error_deg);
538 // Estimate time to waypoint 1.
539 // The estimation does not take track into consideration,
540 // so if you are going away from the waypoint the TTW will
541 // increase. Makes most sense when travelling directly towards
543 if (speed_kt > 0.0 && wp1_distance > 0.0) {
544 wp1_TTW = (wp1_distance * SG_METER_TO_NM) / (speed_kt / 3600);
549 unsigned int wp1_TTW_seconds = (int) (wp1_TTW + 0.5);
550 if (wp1_TTW_seconds < 356400) { // That's 99 hours
551 unsigned int wp1_TTW_minutes = 0;
552 unsigned int wp1_TTW_hours = 0;
554 while (wp1_TTW_seconds >= 3600) {
555 wp1_TTW_seconds -= 3600;
558 while (wp1_TTW_seconds >= 60) {
559 wp1_TTW_seconds -= 60;
562 snprintf(wp1_TTW_str, 9, "%02d:%02d:%02d",
563 wp1_TTW_hours, wp1_TTW_minutes, wp1_TTW_seconds);
564 _wp1_ttw_node->setStringValue(wp1_TTW_str);
567 _wp1_ttw_node->setStringValue("--:--:--");
569 // Course deviation is the diffenrence between the bearing
571 wp1_course_deviation_deg = wp1_bearing_deg - wp1_course_deg;
572 SG_NORMALIZE_RANGE(wp1_course_deviation_deg, -180.0, 180.0);
574 // If the course deviation is less than 90 degrees to either side,
575 // our desired course is towards the waypoint.
576 // It does not matter if we are actually moving
577 // towards or from the waypoint.
578 if (fabs(wp1_course_deviation_deg) < 90.0) {
579 _wp1_to_flag_node->setBoolValue(true); }
580 // If it's more than 90 degrees the desired
581 // course is from the waypoint.
582 else if (fabs(wp1_course_deviation_deg) > 90.0) {
583 _wp1_to_flag_node->setBoolValue(false);
584 // When the course is away from the waypoint,
585 // it makes sense to change the sign of the deviation.
586 wp1_course_deviation_deg *= -1.0;
587 SG_NORMALIZE_RANGE(wp1_course_deviation_deg, -90.0, 90.0);
590 _wp1_course_deviation_node->setDoubleValue(wp1_course_deviation_deg);
592 // Cross track error.
593 wp1_course_error_m = sin(wp1_course_deviation_deg * SG_PI / 180.0)
595 _wp1_course_error_nm_node->setDoubleValue(wp1_course_error_m
599 // Leg course deviation is the diffenrence between the bearing
601 double course_deviation_deg = wp1_bearing_deg - _course_deg;
602 SG_NORMALIZE_RANGE(course_deviation_deg, -180.0, 180.0);
604 // If the course deviation is less than 90 degrees to either side,
605 // our desired course is towards the waypoint.
606 // It does not matter if we are actually moving
607 // towards or from the waypoint.
608 if (fabs(course_deviation_deg) < 90.0) {
609 _leg_to_flag_node->setBoolValue(true); }
610 // If it's more than 90 degrees the desired
611 // course is from the waypoint.
612 else if (fabs(course_deviation_deg) > 90.0) {
613 _leg_to_flag_node->setBoolValue(false);
614 // When the course is away from the waypoint,
615 // it makes sense to change the sign of the deviation.
616 course_deviation_deg *= -1.0;
617 SG_NORMALIZE_RANGE(course_deviation_deg, -90.0, 90.0);
620 _leg_course_deviation_node->setDoubleValue(course_deviation_deg);
622 // Cross track error.
623 double course_error_m = sin(course_deviation_deg * SG_PI / 180.0)
625 _leg_course_error_nm_node->setDoubleValue(course_error_m * SG_METER_TO_NM);
627 // Altitude deviation
628 double desired_altitude_m = wp1_altitude_m
629 + wp1_distance * _alt_dist_ratio;
630 double altitude_deviation_m = altitude_m - desired_altitude_m;
631 _alt_deviation_node->setDoubleValue(altitude_deviation_m * SG_METER_TO_FEET);
636 double tracking_bug = _tracking_bug_node->getDoubleValue();
637 double true_bug_error = tracking_bug - track1_deg;
638 double magnetic_bug_error = tracking_bug - mag_track_bearing;
640 // Get the errors into the (-180,180) range.
641 SG_NORMALIZE_RANGE(true_bug_error, -180.0, 180.0);
642 SG_NORMALIZE_RANGE(magnetic_bug_error, -180.0, 180.0);
644 _true_bug_error_node->setDoubleValue(true_bug_error);
645 _magnetic_bug_error_node->setDoubleValue(magnetic_bug_error);
648 // Add WP 1 to the route.
649 if ( addWp->getBoolValue() )
651 addWp->setBoolValue(false);
653 SGWayPoint tempWp( _wp1_longitude_node->getDoubleValue(),
654 _wp1_latitude_node->getDoubleValue(),
655 _wp1_altitude_node->getDoubleValue(),
657 _wp1_ID_node->getStringValue(),
658 _wp1_name_node->getStringValue() );
660 route->add_waypoint(tempWp);
663 _route->getChild("Waypoint", route->size()-1, true);
664 SGPropertyNode *id = wp->getChild("ID", 0, true);
665 SGPropertyNode *name = wp->getChild("Name", 0, true);
666 SGPropertyNode *lat = wp->getChild("Latitude", 0, true);
667 SGPropertyNode *lon = wp->getChild("Longitude", 0, true);
668 SGPropertyNode *alt = wp->getChild("Altitude", 0, true);
670 id->setStringValue( tempWp.get_id().c_str() );
671 name->setStringValue( tempWp.get_name().c_str() );
672 lat->setDoubleValue( tempWp.get_target_lat() );
673 lon->setDoubleValue( tempWp.get_target_lon() );
674 alt->setDoubleValue( tempWp.get_target_alt() );
677 if ( popWp->getBoolValue() )
679 popWp->setBoolValue(false);
681 route->delete_first();
682 _route->removeChild("Waypoint", 0, false);
686 _true_track_node->setDoubleValue(0.0);
687 _magnetic_track_node->setDoubleValue(0.0);
688 _speed_node->setDoubleValue(0.0);
692 _last_longitude_deg = longitude_deg;
693 _last_latitude_deg = latitude_deg;
694 _last_altitude_m = altitude_m;