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/fix.hxx>
26 #include <Navaids/navlist.hxx>
33 GPS::GPS ( SGPropertyNode *node)
35 _last_longitude_deg(0),
36 _last_latitude_deg(0),
40 _wp0_longitude_deg(0),
43 _wp1_longitude_deg(0),
48 _name(node->getStringValue("name", "gps")),
49 _num(node->getIntValue("number", 0)),
62 delete route; // in case init is called twice
67 branch = "/instrumentation/" + _name;
69 SGPropertyNode *node = fgGetNode(branch.c_str(), _num, true );
71 _longitude_node = fgGetNode("/position/longitude-deg", true);
72 _latitude_node = fgGetNode("/position/latitude-deg", true);
73 _altitude_node = fgGetNode("/position/altitude-ft", true);
74 _magvar_node = fgGetNode("/environment/magnetic-variation-deg", true);
75 _serviceable_node = node->getChild("serviceable", 0, true);
76 _electrical_node = fgGetNode("/systems/electrical/outputs/gps", true);
78 SGPropertyNode *wp_node = node->getChild("wp", 0, true);
79 SGPropertyNode *wp0_node = wp_node->getChild("wp", 0, true);
80 SGPropertyNode *wp1_node = wp_node->getChild("wp", 1, true);
81 addWp = wp1_node->getChild("Add-to-route", 0, true);
83 _wp0_longitude_node = wp0_node->getChild("longitude-deg", 0, true);
84 _wp0_latitude_node = wp0_node->getChild("latitude-deg", 0, true);
85 _wp0_altitude_node = wp0_node->getChild("altitude-ft", 0, true);
86 _wp0_ID_node = wp0_node->getChild("ID", 0, true);
87 _wp0_name_node = wp0_node->getChild("name", 0, true);
88 _wp0_course_node = wp0_node->getChild("desired-course-deg", 0, true);
89 _wp0_waypoint_type_node = wp0_node->getChild("waypoint-type", 0, true);
90 _wp0_distance_node = wp0_node->getChild("distance-nm", 0, true);
91 _wp0_ttw_node = wp0_node->getChild("TTW", 0, true);
92 _wp0_bearing_node = wp0_node->getChild("bearing-true-deg", 0, true);
93 _wp0_mag_bearing_node = wp0_node->getChild("bearing-mag-deg", 0, true);
94 _wp0_course_deviation_node =
95 wp0_node->getChild("course-deviation-deg", 0, true);
96 _wp0_course_error_nm_node = wp0_node->getChild("course-error-nm", 0, true);
97 _wp0_to_flag_node = wp0_node->getChild("to-flag", 0, true);
98 _true_wp0_bearing_error_node =
99 wp0_node->getChild("true-bearing-error-deg", 0, true);
100 _magnetic_wp0_bearing_error_node =
101 wp0_node->getChild("magnetic-bearing-error-deg", 0, true);
103 _wp1_longitude_node = wp1_node->getChild("longitude-deg", 0, true);
104 _wp1_latitude_node = wp1_node->getChild("latitude-deg", 0, true);
105 _wp1_altitude_node = wp1_node->getChild("altitude-ft", 0, true);
106 _wp1_ID_node = wp1_node->getChild("ID", 0, true);
107 _wp1_name_node = wp1_node->getChild("name", 0, true);
108 _wp1_course_node = wp1_node->getChild("desired-course-deg", 0, true);
109 _wp1_waypoint_type_node = wp1_node->getChild("waypoint-type", 0, true);
110 _wp1_distance_node = wp1_node->getChild("distance-nm", 0, true);
111 _wp1_ttw_node = wp1_node->getChild("TTW", 0, true);
112 _wp1_bearing_node = wp1_node->getChild("bearing-true-deg", 0, true);
113 _wp1_mag_bearing_node = wp1_node->getChild("bearing-mag-deg", 0, true);
114 _wp1_course_deviation_node =
115 wp1_node->getChild("course-deviation-deg", 0, true);
116 _wp1_course_error_nm_node = wp1_node->getChild("course-error-nm", 0, true);
117 _wp1_to_flag_node = wp1_node->getChild("to-flag", 0, true);
118 _true_wp1_bearing_error_node =
119 wp1_node->getChild("true-bearing-error-deg", 0, true);
120 _magnetic_wp1_bearing_error_node =
121 wp1_node->getChild("magnetic-bearing-error-deg", 0, true);
122 _get_nearest_airport_node =
123 wp1_node->getChild("get-nearest-airport", 0, true);
125 _tracking_bug_node = node->getChild("tracking-bug", 0, true);
126 _raim_node = node->getChild("raim", 0, true);
128 _indicated_longitude_node =
129 node->getChild("indicated-longitude-deg", 0, true);
130 _indicated_latitude_node =
131 node->getChild("indicated-latitude-deg", 0, true);
132 _indicated_altitude_node =
133 node->getChild("indicated-altitude-ft", 0, true);
134 _indicated_vertical_speed_node =
135 node->getChild("indicated-vertical-speed", 0, true);
137 node->getChild("indicated-track-true-deg", 0, true);
138 _magnetic_track_node =
139 node->getChild("indicated-track-magnetic-deg", 0, true);
141 node->getChild("indicated-ground-speed-kt", 0, true);
143 node->getChild("odometer", 0, true);
144 _trip_odometer_node =
145 node->getChild("trip-odometer", 0, true);
146 _true_bug_error_node =
147 node->getChild("true-bug-error-deg", 0, true);
148 _magnetic_bug_error_node =
149 node->getChild("magnetic-bug-error-deg", 0, true);
152 wp_node->getChild("leg-distance-nm", 0, true);
154 wp_node->getChild("leg-true-course-deg", 0, true);
155 _leg_magnetic_course_node =
156 wp_node->getChild("leg-mag-course-deg", 0, true);
157 _alt_dist_ratio_node =
158 wp_node->getChild("alt-dist-ratio", 0, true);
159 _leg_course_deviation_node =
160 wp_node->getChild("leg-course-deviation-deg", 0, true);
161 _leg_course_error_nm_node =
162 wp_node->getChild("leg-course-error-nm", 0, true);
164 wp_node->getChild("leg-to-flag", 0, true);
165 _alt_deviation_node =
166 wp_node->getChild("alt-deviation-ft", 0, true);
168 _route = node->getChild("route", 0, true);
169 popWp = _route->getChild("Pop-WP", 0, true);
171 addWp->setBoolValue(false);
172 popWp->setBoolValue(false);
174 _serviceable_node->setBoolValue(true);
178 GPS::update (double delta_time_sec)
180 // If it's off, don't bother.
181 if (!_serviceable_node->getBoolValue() ||
182 !_electrical_node->getBoolValue()) {
184 _last_longitude_deg = 0;
185 _last_latitude_deg = 0;
186 _last_altitude_m = 0;
188 _raim_node->setDoubleValue(false);
189 _indicated_longitude_node->setDoubleValue(0);
190 _indicated_latitude_node->setDoubleValue(0);
191 _indicated_altitude_node->setDoubleValue(0);
192 _indicated_vertical_speed_node->setDoubleValue(0);
193 _true_track_node->setDoubleValue(0);
194 _magnetic_track_node->setDoubleValue(0);
195 _speed_node->setDoubleValue(0);
196 _wp1_distance_node->setDoubleValue(0);
197 _wp1_bearing_node->setDoubleValue(0);
198 _wp1_longitude_node->setDoubleValue(0);
199 _wp1_latitude_node->setDoubleValue(0);
200 _wp1_course_node->setDoubleValue(0);
201 _odometer_node->setDoubleValue(0);
202 _trip_odometer_node->setDoubleValue(0);
203 _tracking_bug_node->setDoubleValue(0);
204 _true_bug_error_node->setDoubleValue(0);
205 _magnetic_bug_error_node->setDoubleValue(0);
206 _true_wp1_bearing_error_node->setDoubleValue(0);
207 _magnetic_wp1_bearing_error_node->setDoubleValue(0);
211 // Get the aircraft position
212 // TODO: Add noise and other errors.
213 double longitude_deg = _longitude_node->getDoubleValue();
214 double latitude_deg = _latitude_node->getDoubleValue();
215 double altitude_m = _altitude_node->getDoubleValue() * SG_FEET_TO_METER;
216 double magvar_deg = _magvar_node->getDoubleValue();
220 // Bias and random error
221 double random_factor = sg_random();
222 double random_error = 1.4;
223 double error_radius = 5.1;
224 double bias_max_radius = 5.1;
225 double random_max_radius = 1.4;
227 bias_length += (random_factor-0.5) * 1.0e-3;
228 if (bias_length <= 0.0) bias_length = 0.0;
229 else if (bias_length >= bias_max_radius) bias_length = bias_max_radius;
230 bias_angle += (random_factor-0.5) * 1.0e-3;
231 if (bias_angle <= 0.0) bias_angle = 0.0;
232 else if (bias_angle >= 360.0) bias_angle = 360.0;
234 double random_length = random_factor * random_max_radius;
235 double random_angle = random_factor * 360.0;
237 double bias_x = bias_length * cos(bias_angle * SG_PI / 180.0);
238 double bias_y = bias_length * sin(bias_angle * SG_PI / 180.0);
239 double random_x = random_length * cos(random_angle * SG_PI / 180.0);
240 double random_y = random_length * sin(random_angle * SG_PI / 180.0);
241 double error_x = bias_x + random_x;
242 double error_y = bias_y + random_y;
243 double error_length = sqrt(error_x*error_x + error_y*error_y);
244 double error_angle = atan(error_y / error_x) * 180.0 / SG_PI;
249 geo_direct_wgs_84 ( altitude_m, latitude_deg,
250 longitude_deg, error_angle,
251 error_length, &lat2, &lon2,
253 //cout << lat2 << " " << lon2 << endl;
254 printf("%f %f \n", bias_length, bias_angle);
255 printf("%3.7f %3.7f \n", lat2, lon2);
256 printf("%f %f \n", error_length, error_angle);
262 double speed_kt, vertical_speed_mpm;
264 _raim_node->setBoolValue(true);
265 _indicated_longitude_node->setDoubleValue(longitude_deg);
266 _indicated_latitude_node->setDoubleValue(latitude_deg);
267 _indicated_altitude_node->setDoubleValue(altitude_m * SG_METER_TO_FEET);
270 double track1_deg, track2_deg, distance_m, odometer, mag_track_bearing;
271 geo_inverse_wgs_84(altitude_m,
272 _last_latitude_deg, _last_longitude_deg,
273 latitude_deg, longitude_deg,
274 &track1_deg, &track2_deg, &distance_m);
275 speed_kt = ((distance_m * SG_METER_TO_NM) *
276 ((1 / delta_time_sec) * 3600.0));
277 vertical_speed_mpm = ((altitude_m - _last_altitude_m) * 60 /
279 _indicated_vertical_speed_node->setDoubleValue
280 (vertical_speed_mpm * SG_METER_TO_FEET);
281 _true_track_node->setDoubleValue(track1_deg);
282 mag_track_bearing = track1_deg - magvar_deg;
283 SG_NORMALIZE_RANGE(mag_track_bearing, 0.0, 360.0);
284 _magnetic_track_node->setDoubleValue(mag_track_bearing);
285 speed_kt = fgGetLowPass(_last_speed_kts, speed_kt, delta_time_sec/20.0);
286 _last_speed_kts = speed_kt;
287 _speed_node->setDoubleValue(speed_kt);
289 odometer = _odometer_node->getDoubleValue();
290 _odometer_node->setDoubleValue(odometer + distance_m * SG_METER_TO_NM);
291 odometer = _trip_odometer_node->getDoubleValue();
292 _trip_odometer_node->setDoubleValue(odometer + distance_m * SG_METER_TO_NM);
294 // Get waypoint 0 position
295 double wp0_longitude_deg = _wp0_longitude_node->getDoubleValue();
296 double wp0_latitude_deg = _wp0_latitude_node->getDoubleValue();
297 double wp0_altitude_m = _wp0_altitude_node->getDoubleValue()
299 double wp0_course_deg = _wp0_course_node->getDoubleValue();
300 double wp0_distance, wp0_bearing_deg, wp0_course_deviation_deg,
301 wp0_course_error_m, wp0_TTW, wp0_bearing_error_deg;
302 string wp0_ID = _wp0_ID_node->getStringValue();
304 // Get waypoint 1 position
305 double wp1_longitude_deg = _wp1_longitude_node->getDoubleValue();
306 double wp1_latitude_deg = _wp1_latitude_node->getDoubleValue();
307 double wp1_altitude_m = _wp1_altitude_node->getDoubleValue()
309 double wp1_course_deg = _wp1_course_node->getDoubleValue();
310 double wp1_distance, wp1_bearing_deg, wp1_course_deviation_deg,
311 wp1_course_error_m, wp1_TTW, wp1_bearing_error_deg;
312 string wp1_ID = _wp1_ID_node->getStringValue();
314 // If the get-nearest-airport-node is true.
315 // Get the nearest airport, and set it as waypoint 1.
316 if (_get_nearest_airport_node->getBoolValue()) {
317 const FGAirport* a = globals->get_airports()->search(longitude_deg, latitude_deg, 360.0);
319 _wp1_ID_node->setStringValue(a->getId().c_str());
320 wp1_longitude_deg = a->getLongitude();
321 wp1_latitude_deg = a->getLatitude();
322 _wp1_name_node->setStringValue(a->getName().c_str());
323 _get_nearest_airport_node->setBoolValue(false);
324 _last_wp1_ID = wp1_ID = a->getId().c_str();
328 // If the waypoint 0 ID has changed, try to find the new ID
329 // in the airport-, fix-, nav-database.
330 if ( !(_last_wp0_ID == wp0_ID) ) {
331 string waypont_type =
332 _wp0_waypoint_type_node->getStringValue();
333 if (waypont_type == "airport") {
334 const FGAirport* a = globals->get_airports()->search( wp0_ID );
336 wp0_longitude_deg = a->getLongitude();
337 wp0_latitude_deg = a->getLatitude();
338 _wp0_name_node->setStringValue(a->getName().c_str());
341 else if (waypont_type == "nav") {
343 = globals->get_navlist()->findByIdent(wp0_ID.c_str(),
347 //cout << "Nav found" << endl;
348 wp0_longitude_deg = n->get_lon();
349 wp0_latitude_deg = n->get_lat();
350 _wp0_name_node->setStringValue(n->get_name().c_str());
353 else if (waypont_type == "fix") {
355 if ( globals->get_fixlist()->query(wp0_ID, f) ) {
356 //cout << "Fix found" << endl;
357 wp0_longitude_deg = f->get_lon();
358 wp0_latitude_deg = f->get_lat();
359 _wp0_name_node->setStringValue(wp0_ID.c_str());
362 _last_wp0_ID = wp0_ID;
365 // If the waypoint 1 ID has changed, try to find the new ID
366 // in the airport-, fix-, nav-database.
367 if ( !(_last_wp1_ID == wp1_ID) ) {
368 string waypont_type =
369 _wp1_waypoint_type_node->getStringValue();
370 if (waypont_type == "airport") {
371 const FGAirport* a = globals->get_airports()->search( wp1_ID );
373 wp1_longitude_deg = a->getLongitude();
374 wp1_latitude_deg = a->getLatitude();
375 _wp1_name_node->setStringValue(a->getName().c_str());
378 else if (waypont_type == "nav") {
380 = globals->get_navlist()->findByIdent(wp1_ID.c_str(),
384 //cout << "Nav found" << endl;
385 wp1_longitude_deg = n->get_lon();
386 wp1_latitude_deg = n->get_lat();
387 _wp1_name_node->setStringValue(n->get_name().c_str());
390 else if (waypont_type == "fix") {
392 if ( globals->get_fixlist()->query(wp1_ID, f) ) {
393 //cout << "Fix found" << endl;
394 wp1_longitude_deg = f->get_lon();
395 wp1_latitude_deg = f->get_lat();
396 _wp1_name_node->setStringValue(wp1_ID.c_str());
399 _last_wp1_ID = wp1_ID;
404 // If any of the two waypoints have changed
405 // we need to calculate a new course between them,
406 // and values for vertical navigation.
407 if ( wp0_longitude_deg != _wp0_longitude_deg ||
408 wp0_latitude_deg != _wp0_latitude_deg ||
409 wp0_altitude_m != _wp0_altitude_m ||
410 wp1_longitude_deg != _wp1_longitude_deg ||
411 wp1_latitude_deg != _wp1_latitude_deg ||
412 wp1_altitude_m != _wp1_altitude_m )
414 // Update the global variables
415 _wp0_longitude_deg = wp0_longitude_deg;
416 _wp0_latitude_deg = wp0_latitude_deg;
417 _wp0_altitude_m = wp0_altitude_m;
418 _wp1_longitude_deg = wp1_longitude_deg;
419 _wp1_latitude_deg = wp1_latitude_deg;
420 _wp1_altitude_m = wp1_altitude_m;
422 // Get the course and distance from wp0 to wp1
423 SGWayPoint wp0(wp0_longitude_deg,
424 wp0_latitude_deg, wp0_altitude_m);
425 SGWayPoint wp1(wp1_longitude_deg,
426 wp1_latitude_deg, wp1_altitude_m);
428 wp1.CourseAndDistance(wp0, &_course_deg, &_distance_m);
429 double leg_mag_course = _course_deg - magvar_deg;
430 SG_NORMALIZE_RANGE(leg_mag_course, 0.0, 360.0);
432 // Get the altitude / distance ratio
433 if ( distance_m > 0.0 ) {
434 double alt_difference_m = wp0_altitude_m - wp1_altitude_m;
435 _alt_dist_ratio = alt_difference_m / _distance_m;
438 _leg_distance_node->setDoubleValue(_distance_m * SG_METER_TO_NM);
439 _leg_course_node->setDoubleValue(_course_deg);
440 _leg_magnetic_course_node->setDoubleValue(leg_mag_course);
441 _alt_dist_ratio_node->setDoubleValue(_alt_dist_ratio);
443 _wp0_longitude_node->setDoubleValue(wp0_longitude_deg);
444 _wp0_latitude_node->setDoubleValue(wp0_latitude_deg);
445 _wp1_longitude_node->setDoubleValue(wp1_longitude_deg);
446 _wp1_latitude_node->setDoubleValue(wp1_latitude_deg);
450 // Find the bearing and distance to waypoint 0.
451 SGWayPoint wp0(wp0_longitude_deg, wp0_latitude_deg, wp0_altitude_m);
452 wp0.CourseAndDistance(longitude_deg, latitude_deg, altitude_m,
453 &wp0_bearing_deg, &wp0_distance);
454 _wp0_distance_node->setDoubleValue(wp0_distance * SG_METER_TO_NM);
455 _wp0_bearing_node->setDoubleValue(wp0_bearing_deg);
456 double wp0_mag_bearing_deg = wp0_bearing_deg - magvar_deg;
457 SG_NORMALIZE_RANGE(wp0_mag_bearing_deg, 0.0, 360.0);
458 _wp0_mag_bearing_node->setDoubleValue(wp0_mag_bearing_deg);
459 wp0_bearing_error_deg = track1_deg - wp0_bearing_deg;
460 SG_NORMALIZE_RANGE(wp0_bearing_error_deg, -180.0, 180.0);
461 _true_wp0_bearing_error_node->setDoubleValue(wp0_bearing_error_deg);
463 // Estimate time to waypoint 0.
464 // The estimation does not take track into consideration,
465 // so if you are going away from the waypoint the TTW will
466 // increase. Makes most sense when travelling directly towards
468 if (speed_kt > 0.0 && wp0_distance > 0.0) {
469 wp0_TTW = (wp0_distance * SG_METER_TO_NM) / (speed_kt / 3600);
474 unsigned int wp0_TTW_seconds = (int) (wp0_TTW + 0.5);
475 if (wp0_TTW_seconds < 356400) { // That's 99 hours
476 unsigned int wp0_TTW_minutes = 0;
477 unsigned int wp0_TTW_hours = 0;
479 while (wp0_TTW_seconds >= 3600) {
480 wp0_TTW_seconds -= 3600;
483 while (wp0_TTW_seconds >= 60) {
484 wp0_TTW_seconds -= 60;
487 snprintf(wp0_TTW_str, 9, "%02d:%02d:%02d",
488 wp0_TTW_hours, wp0_TTW_minutes, wp0_TTW_seconds);
489 _wp0_ttw_node->setStringValue(wp0_TTW_str);
492 _wp0_ttw_node->setStringValue("--:--:--");
494 // Course deviation is the diffenrence between the bearing
496 wp0_course_deviation_deg = wp0_bearing_deg -
498 SG_NORMALIZE_RANGE(wp0_course_deviation_deg, -180.0, 180.0);
500 // If the course deviation is less than 90 degrees to either side,
501 // our desired course is towards the waypoint.
502 // It does not matter if we are actually moving
503 // towards or from the waypoint.
504 if (fabs(wp0_course_deviation_deg) < 90.0) {
505 _wp0_to_flag_node->setBoolValue(true); }
506 // If it's more than 90 degrees the desired
507 // course is from the waypoint.
508 else if (fabs(wp0_course_deviation_deg) > 90.0) {
509 _wp0_to_flag_node->setBoolValue(false);
510 // When the course is away from the waypoint,
511 // it makes sense to change the sign of the deviation.
512 wp0_course_deviation_deg *= -1.0;
513 SG_NORMALIZE_RANGE(wp0_course_deviation_deg, -90.0, 90.0);
516 _wp0_course_deviation_node->setDoubleValue(wp0_course_deviation_deg);
518 // Cross track error.
519 wp0_course_error_m = sin(wp0_course_deviation_deg * SG_PI / 180.0)
521 _wp0_course_error_nm_node->setDoubleValue(wp0_course_error_m
526 // Find the bearing and distance to waypoint 1.
527 SGWayPoint wp1(wp1_longitude_deg, wp1_latitude_deg, wp1_altitude_m);
528 wp1.CourseAndDistance(longitude_deg, latitude_deg, altitude_m,
529 &wp1_bearing_deg, &wp1_distance);
530 _wp1_distance_node->setDoubleValue(wp1_distance * SG_METER_TO_NM);
531 _wp1_bearing_node->setDoubleValue(wp1_bearing_deg);
532 double wp1_mag_bearing_deg = wp1_bearing_deg - magvar_deg;
533 SG_NORMALIZE_RANGE(wp1_mag_bearing_deg, 0.0, 360.0);
534 _wp1_mag_bearing_node->setDoubleValue(wp1_mag_bearing_deg);
535 wp1_bearing_error_deg = track1_deg - wp1_bearing_deg;
536 SG_NORMALIZE_RANGE(wp1_bearing_error_deg, -180.0, 180.0);
537 _true_wp1_bearing_error_node->setDoubleValue(wp1_bearing_error_deg);
539 // Estimate time to waypoint 1.
540 // The estimation does not take track into consideration,
541 // so if you are going away from the waypoint the TTW will
542 // increase. Makes most sense when travelling directly towards
544 if (speed_kt > 0.0 && wp1_distance > 0.0) {
545 wp1_TTW = (wp1_distance * SG_METER_TO_NM) / (speed_kt / 3600);
550 unsigned int wp1_TTW_seconds = (int) (wp1_TTW + 0.5);
551 if (wp1_TTW_seconds < 356400) { // That's 99 hours
552 unsigned int wp1_TTW_minutes = 0;
553 unsigned int wp1_TTW_hours = 0;
555 while (wp1_TTW_seconds >= 3600) {
556 wp1_TTW_seconds -= 3600;
559 while (wp1_TTW_seconds >= 60) {
560 wp1_TTW_seconds -= 60;
563 snprintf(wp1_TTW_str, 9, "%02d:%02d:%02d",
564 wp1_TTW_hours, wp1_TTW_minutes, wp1_TTW_seconds);
565 _wp1_ttw_node->setStringValue(wp1_TTW_str);
568 _wp1_ttw_node->setStringValue("--:--:--");
570 // Course deviation is the diffenrence between the bearing
572 wp1_course_deviation_deg = wp1_bearing_deg - wp1_course_deg;
573 SG_NORMALIZE_RANGE(wp1_course_deviation_deg, -180.0, 180.0);
575 // If the course deviation is less than 90 degrees to either side,
576 // our desired course is towards the waypoint.
577 // It does not matter if we are actually moving
578 // towards or from the waypoint.
579 if (fabs(wp1_course_deviation_deg) < 90.0) {
580 _wp1_to_flag_node->setBoolValue(true); }
581 // If it's more than 90 degrees the desired
582 // course is from the waypoint.
583 else if (fabs(wp1_course_deviation_deg) > 90.0) {
584 _wp1_to_flag_node->setBoolValue(false);
585 // When the course is away from the waypoint,
586 // it makes sense to change the sign of the deviation.
587 wp1_course_deviation_deg *= -1.0;
588 SG_NORMALIZE_RANGE(wp1_course_deviation_deg, -90.0, 90.0);
591 _wp1_course_deviation_node->setDoubleValue(wp1_course_deviation_deg);
593 // Cross track error.
594 wp1_course_error_m = sin(wp1_course_deviation_deg * SG_PI / 180.0)
596 _wp1_course_error_nm_node->setDoubleValue(wp1_course_error_m
600 // Leg course deviation is the diffenrence between the bearing
602 double course_deviation_deg = wp1_bearing_deg - _course_deg;
603 SG_NORMALIZE_RANGE(course_deviation_deg, -180.0, 180.0);
605 // If the course deviation is less than 90 degrees to either side,
606 // our desired course is towards the waypoint.
607 // It does not matter if we are actually moving
608 // towards or from the waypoint.
609 if (fabs(course_deviation_deg) < 90.0) {
610 _leg_to_flag_node->setBoolValue(true); }
611 // If it's more than 90 degrees the desired
612 // course is from the waypoint.
613 else if (fabs(course_deviation_deg) > 90.0) {
614 _leg_to_flag_node->setBoolValue(false);
615 // When the course is away from the waypoint,
616 // it makes sense to change the sign of the deviation.
617 course_deviation_deg *= -1.0;
618 SG_NORMALIZE_RANGE(course_deviation_deg, -90.0, 90.0);
621 _leg_course_deviation_node->setDoubleValue(course_deviation_deg);
623 // Cross track error.
624 double course_error_m = sin(course_deviation_deg * SG_PI / 180.0)
626 _leg_course_error_nm_node->setDoubleValue(course_error_m * SG_METER_TO_NM);
628 // Altitude deviation
629 double desired_altitude_m = wp1_altitude_m
630 + wp1_distance * _alt_dist_ratio;
631 double altitude_deviation_m = altitude_m - desired_altitude_m;
632 _alt_deviation_node->setDoubleValue(altitude_deviation_m * SG_METER_TO_FEET);
637 double tracking_bug = _tracking_bug_node->getDoubleValue();
638 double true_bug_error = tracking_bug - track1_deg;
639 double magnetic_bug_error = tracking_bug - mag_track_bearing;
641 // Get the errors into the (-180,180) range.
642 SG_NORMALIZE_RANGE(true_bug_error, -180.0, 180.0);
643 SG_NORMALIZE_RANGE(magnetic_bug_error, -180.0, 180.0);
645 _true_bug_error_node->setDoubleValue(true_bug_error);
646 _magnetic_bug_error_node->setDoubleValue(magnetic_bug_error);
649 // Add WP 1 to the route.
650 if ( addWp->getBoolValue() )
652 addWp->setBoolValue(false);
654 SGWayPoint tempWp( _wp1_longitude_node->getDoubleValue(),
655 _wp1_latitude_node->getDoubleValue(),
656 _wp1_altitude_node->getDoubleValue(),
658 _wp1_ID_node->getStringValue(),
659 _wp1_name_node->getStringValue() );
661 route->add_waypoint(tempWp);
664 _route->getChild("Waypoint", route->size()-1, true);
665 SGPropertyNode *id = wp->getChild("ID", 0, true);
666 SGPropertyNode *name = wp->getChild("Name", 0, true);
667 SGPropertyNode *lat = wp->getChild("Latitude", 0, true);
668 SGPropertyNode *lon = wp->getChild("Longitude", 0, true);
669 SGPropertyNode *alt = wp->getChild("Altitude", 0, true);
671 id->setStringValue( tempWp.get_id().c_str() );
672 name->setStringValue( tempWp.get_name().c_str() );
673 lat->setDoubleValue( tempWp.get_target_lat() );
674 lon->setDoubleValue( tempWp.get_target_lon() );
675 alt->setDoubleValue( tempWp.get_target_alt() );
678 if ( popWp->getBoolValue() )
680 popWp->setBoolValue(false);
682 route->delete_first();
683 _route->removeChild("Waypoint", 0, false);
687 _true_track_node->setDoubleValue(0.0);
688 _magnetic_track_node->setDoubleValue(0.0);
689 _speed_node->setDoubleValue(0.0);
693 _last_longitude_deg = longitude_deg;
694 _last_latitude_deg = latitude_deg;
695 _last_altitude_m = altitude_m;