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),
38 for ( i = 0; i < node->nChildren(); ++i ) {
39 SGPropertyNode *child = node->getChild(i);
40 string cname = child->getName();
41 string cval = child->getStringValue();
42 if ( cname == "name" ) {
44 } else if ( cname == "number" ) {
45 num = child->getIntValue();
47 SG_LOG( SG_AUTOPILOT, SG_WARN, "Error in gps config logic" );
48 if ( name.length() ) {
49 SG_LOG( SG_AUTOPILOT, SG_WARN, "Section = " << name );
57 _last_longitude_deg(0),
58 _last_latitude_deg(0),
75 branch = "/instrumentation/" + name;
77 SGPropertyNode *node = fgGetNode(branch.c_str(), num, true );
79 _longitude_node = fgGetNode("/position/longitude-deg", true);
80 _latitude_node = fgGetNode("/position/latitude-deg", true);
81 _altitude_node = fgGetNode("/position/altitude-ft", true);
82 _magvar_node = fgGetNode("/environment/magnetic-variation-deg", true);
83 _serviceable_node = node->getChild("serviceable", 0, true);
84 _electrical_node = fgGetNode("/systems/electrical/outputs/gps", true);
86 SGPropertyNode *wp_node = node->getChild("wp", 0, true);
87 SGPropertyNode *wp0_node = wp_node->getChild("wp", 0, true);
88 SGPropertyNode *wp1_node = wp_node->getChild("wp", 1, true);
89 addWp = wp1_node->getChild("Add-to-route", 0, true);
91 _wp0_longitude_node = wp0_node->getChild("longitude-deg", 0, true);
92 _wp0_latitude_node = wp0_node->getChild("latitude-deg", 0, true);
93 _wp0_altitude_node = wp0_node->getChild("altitude-deg", 0, true);
94 _wp0_ID_node = wp0_node->getChild("ID", 0, true);
95 _wp0_name_node = wp0_node->getChild("name", 0, true);
96 _wp0_course_node = wp0_node->getChild("desired-course-deg", 0, true);
97 _wp0_waypoint_type_node = wp0_node->getChild("waypoint-type", 0, true);
98 _wp0_distance_node = wp0_node->getChild("distance-nm", 0, true);
99 _wp0_ttw_node = wp0_node->getChild("TTW", 0, true);
100 _wp0_bearing_node = wp0_node->getChild("bearing-true-deg", 0, true);
101 _wp0_mag_bearing_node = wp0_node->getChild("bearing-mag-deg", 0, true);
102 _wp0_course_deviation_node =
103 wp0_node->getChild("course-deviation-deg", 0, true);
104 _wp0_course_error_nm_node = wp0_node->getChild("course-error-nm", 0, true);
105 _wp0_to_flag_node = wp0_node->getChild("to-flag", 0, true);
106 _true_wp0_bearing_error_node =
107 wp0_node->getChild("true-bearing-error-deg", 0, true);
108 _magnetic_wp0_bearing_error_node =
109 wp0_node->getChild("magnetic-bearing-error-deg", 0, true);
111 _wp1_longitude_node = wp1_node->getChild("longitude-deg", 0, true);
112 _wp1_latitude_node = wp1_node->getChild("latitude-deg", 0, true);
113 _wp1_altitude_node = wp1_node->getChild("altitude-deg", 0, true);
114 _wp1_ID_node = wp1_node->getChild("ID", 0, true);
115 _wp1_name_node = wp1_node->getChild("name", 0, true);
116 _wp1_course_node = wp1_node->getChild("desired-course-deg", 0, true);
117 _wp1_waypoint_type_node = wp1_node->getChild("waypoint-type", 0, true);
118 _wp1_distance_node = wp1_node->getChild("distance-nm", 0, true);
119 _wp1_ttw_node = wp1_node->getChild("TTW", 0, true);
120 _wp1_bearing_node = wp1_node->getChild("bearing-true-deg", 0, true);
121 _wp1_mag_bearing_node = wp1_node->getChild("bearing-mag-deg", 0, true);
122 _wp1_course_deviation_node =
123 wp1_node->getChild("course-deviation-deg", 0, true);
124 _wp1_course_error_nm_node = wp1_node->getChild("course-error-nm", 0, true);
125 _wp1_to_flag_node = wp1_node->getChild("to-flag", 0, true);
126 _true_wp1_bearing_error_node =
127 wp1_node->getChild("true-bearing-error-deg", 0, true);
128 _magnetic_wp1_bearing_error_node =
129 wp1_node->getChild("magnetic-bearing-error-deg", 0, true);
130 _get_nearest_airport_node =
131 wp1_node->getChild("get-nearest-airport", 0, true);
133 _tracking_bug_node = node->getChild("tracking-bug", 0, true);
134 _raim_node = node->getChild("raim", 0, true);
136 _indicated_longitude_node =
137 node->getChild("indicated-longitude-deg", 0, true);
138 _indicated_latitude_node =
139 node->getChild("indicated-latitude-deg", 0, true);
140 _indicated_altitude_node =
141 node->getChild("indicated-altitude-ft", 0, true);
142 _indicated_vertical_speed_node =
143 node->getChild("indicated-vertical-speed", 0, true);
145 node->getChild("indicated-track-true-deg", 0, true);
146 _magnetic_track_node =
147 node->getChild("indicated-track_magnetic-deg", 0, true);
149 node->getChild("indicated-ground-speed-kt", 0, true);
151 node->getChild("odometer", 0, true);
152 _trip_odometer_node =
153 node->getChild("trip-odometer", 0, true);
154 _true_bug_error_node =
155 node->getChild("true-bug-error-deg", 0, true);
156 _magnetic_bug_error_node =
157 node->getChild("magnetic-bug-error-deg", 0, true);
160 wp_node->getChild("leg-distance-nm", 0, true);
162 wp_node->getChild("leg-true-course-deg", 0, true);
163 _leg_magnetic_course_node =
164 wp_node->getChild("leg-mag-course-deg", 0, true);
165 _alt_dist_ratio_node =
166 wp_node->getChild("alt-dist-ratio", 0, true);
167 _leg_course_deviation_node =
168 wp_node->getChild("leg-course-deviation-deg", 0, true);
169 _leg_course_error_nm_node =
170 wp_node->getChild("leg-course-error-nm", 0, true);
172 wp_node->getChild("leg-to-flag", 0, true);
173 _alt_deviation_node =
174 wp_node->getChild("alt-deviation-ft", 0, true);
176 _route = node->getChild("route", 0, true);
177 popWp = _route->getChild("Pop-WP", 0, true);
179 addWp->setBoolValue(false);
180 popWp->setBoolValue(false);
182 _serviceable_node->setBoolValue(true);
186 GPS::update (double delta_time_sec)
188 // If it's off, don't bother.
189 if (!_serviceable_node->getBoolValue() ||
190 !_electrical_node->getBoolValue()) {
192 _last_longitude_deg = 0;
193 _last_latitude_deg = 0;
194 _last_altitude_m = 0;
196 _raim_node->setDoubleValue(false);
197 _indicated_longitude_node->setDoubleValue(0);
198 _indicated_latitude_node->setDoubleValue(0);
199 _indicated_altitude_node->setDoubleValue(0);
200 _indicated_vertical_speed_node->setDoubleValue(0);
201 _true_track_node->setDoubleValue(0);
202 _magnetic_track_node->setDoubleValue(0);
203 _speed_node->setDoubleValue(0);
204 _wp1_distance_node->setDoubleValue(0);
205 _wp1_bearing_node->setDoubleValue(0);
206 _wp1_longitude_node->setDoubleValue(0);
207 _wp1_latitude_node->setDoubleValue(0);
208 _wp1_course_node->setDoubleValue(0);
209 _odometer_node->setDoubleValue(0);
210 _trip_odometer_node->setDoubleValue(0);
211 _tracking_bug_node->setDoubleValue(0);
212 _true_bug_error_node->setDoubleValue(0);
213 _magnetic_bug_error_node->setDoubleValue(0);
214 _true_wp1_bearing_error_node->setDoubleValue(0);
215 _magnetic_wp1_bearing_error_node->setDoubleValue(0);
219 // Get the aircraft position
220 // TODO: Add noise and other errors.
221 double longitude_deg = _longitude_node->getDoubleValue();
222 double latitude_deg = _latitude_node->getDoubleValue();
223 double altitude_m = _altitude_node->getDoubleValue() * SG_FEET_TO_METER;
224 double magvar_deg = _magvar_node->getDoubleValue();
228 // Bias and random error
229 double random_factor = sg_random();
230 double random_error = 1.4;
231 double error_radius = 5.1;
232 double bias_max_radius = 5.1;
233 double random_max_radius = 1.4;
235 bias_length += (random_factor-0.5) * 1.0e-3;
236 if (bias_length <= 0.0) bias_length = 0.0;
237 else if (bias_length >= bias_max_radius) bias_length = bias_max_radius;
238 bias_angle += (random_factor-0.5) * 1.0e-3;
239 if (bias_angle <= 0.0) bias_angle = 0.0;
240 else if (bias_angle >= 360.0) bias_angle = 360.0;
242 double random_length = random_factor * random_max_radius;
243 double random_angle = random_factor * 360.0;
245 double bias_x = bias_length * cos(bias_angle * SG_PI / 180.0);
246 double bias_y = bias_length * sin(bias_angle * SG_PI / 180.0);
247 double random_x = random_length * cos(random_angle * SG_PI / 180.0);
248 double random_y = random_length * sin(random_angle * SG_PI / 180.0);
249 double error_x = bias_x + random_x;
250 double error_y = bias_y + random_y;
251 double error_length = sqrt(error_x*error_x + error_y*error_y);
252 double error_angle = atan(error_y / error_x) * 180.0 / SG_PI;
257 geo_direct_wgs_84 ( altitude_m, latitude_deg,
258 longitude_deg, error_angle,
259 error_length, &lat2, &lon2,
261 //cout << lat2 << " " << lon2 << endl;
262 printf("%f %f \n", bias_length, bias_angle);
263 printf("%3.7f %3.7f \n", lat2, lon2);
264 printf("%f %f \n", error_length, error_angle);
270 double speed_kt, vertical_speed_mpm;
272 _raim_node->setBoolValue(true);
273 _indicated_longitude_node->setDoubleValue(longitude_deg);
274 _indicated_latitude_node->setDoubleValue(latitude_deg);
275 _indicated_altitude_node->setDoubleValue(altitude_m * SG_METER_TO_FEET);
278 double track1_deg, track2_deg, distance_m, odometer, mag_track_bearing;
279 geo_inverse_wgs_84(altitude_m,
280 _last_latitude_deg, _last_longitude_deg,
281 latitude_deg, longitude_deg,
282 &track1_deg, &track2_deg, &distance_m);
283 speed_kt = ((distance_m * SG_METER_TO_NM) *
284 ((1 / delta_time_sec) * 3600.0));
285 vertical_speed_mpm = ((altitude_m - _last_altitude_m) * 60 /
287 _indicated_vertical_speed_node->setDoubleValue
288 (vertical_speed_mpm * SG_METER_TO_FEET);
289 _true_track_node->setDoubleValue(track1_deg);
290 mag_track_bearing = track1_deg - magvar_deg;
291 SG_NORMALIZE_RANGE(mag_track_bearing, 0.0, 360.0);
292 _magnetic_track_node->setDoubleValue(mag_track_bearing);
293 speed_kt = fgGetLowPass(_last_speed_kts, speed_kt, delta_time_sec/20.0);
294 _last_speed_kts = speed_kt;
295 _speed_node->setDoubleValue(speed_kt);
297 odometer = _odometer_node->getDoubleValue();
298 _odometer_node->setDoubleValue(odometer + distance_m * SG_METER_TO_NM);
299 odometer = _trip_odometer_node->getDoubleValue();
300 _trip_odometer_node->setDoubleValue(odometer + distance_m * SG_METER_TO_NM);
302 // Get waypoint 0 position
303 double wp0_longitude_deg = _wp0_longitude_node->getDoubleValue();
304 double wp0_latitude_deg = _wp0_latitude_node->getDoubleValue();
305 double wp0_altitude_m = _wp0_altitude_node->getDoubleValue()
307 double wp0_course_deg = _wp0_course_node->getDoubleValue();
308 double wp0_distance, wp0_bearing_deg, wp0_course_deviation_deg,
309 wp0_course_error_m, wp0_TTW, wp0_bearing_error_deg;
310 string wp0_ID = _wp0_ID_node->getStringValue();
312 // Get waypoint 1 position
313 double wp1_longitude_deg = _wp1_longitude_node->getDoubleValue();
314 double wp1_latitude_deg = _wp1_latitude_node->getDoubleValue();
315 double wp1_altitude_m = _wp1_altitude_node->getDoubleValue()
317 double wp1_course_deg = _wp1_course_node->getDoubleValue();
318 double wp1_distance, wp1_bearing_deg, wp1_course_deviation_deg,
319 wp1_course_error_m, wp1_TTW, wp1_bearing_error_deg;
320 string wp1_ID = _wp1_ID_node->getStringValue();
322 // If the get-nearest-airport-node is true.
323 // Get the nearest airport, and set it as waypoint 1.
324 if (_get_nearest_airport_node->getBoolValue()) {
326 //cout << "Airport found" << endl;
327 a = globals->get_airports()->search(longitude_deg, latitude_deg, false);
328 _wp1_ID_node->setStringValue(a.id.c_str());
329 wp1_longitude_deg = a.longitude;
330 wp1_latitude_deg = a.latitude;
331 _wp1_name_node->setStringValue(a.name.c_str());
332 _get_nearest_airport_node->setBoolValue(false);
333 _last_wp1_ID = wp1_ID = a.id.c_str();
336 // If the waypoint 0 ID has changed, try to find the new ID
337 // in the airport-, fix-, nav-database.
338 if ( !(_last_wp0_ID == wp0_ID) ) {
339 string waypont_type =
340 _wp0_waypoint_type_node->getStringValue();
341 if (waypont_type == "airport") {
343 a = globals->get_airports()->search( wp0_ID );
344 if ( a.id == wp0_ID ) {
345 //cout << "Airport found" << endl;
346 wp0_longitude_deg = a.longitude;
347 wp0_latitude_deg = a.latitude;
348 _wp0_name_node->setStringValue(a.name.c_str());
351 else if (waypont_type == "nav") {
353 = globals->get_navlist()->findByIdent(wp0_ID.c_str(),
357 //cout << "Nav found" << endl;
358 wp0_longitude_deg = n->get_lon();
359 wp0_latitude_deg = n->get_lat();
360 _wp0_name_node->setStringValue(n->get_name().c_str());
363 else if (waypont_type == "fix") {
365 if ( globals->get_fixlist()->query(wp0_ID, &f) ) {
366 //cout << "Fix found" << endl;
367 wp0_longitude_deg = f.get_lon();
368 wp0_latitude_deg = f.get_lat();
369 _wp0_name_node->setStringValue(wp0_ID.c_str());
372 _last_wp0_ID = wp0_ID;
375 // If the waypoint 1 ID has changed, try to find the new ID
376 // in the airport-, fix-, nav-database.
377 if ( !(_last_wp1_ID == wp1_ID) ) {
378 string waypont_type =
379 _wp1_waypoint_type_node->getStringValue();
380 if (waypont_type == "airport") {
382 a = globals->get_airports()->search( wp1_ID );
383 if ( a.id == wp1_ID ) {
384 //cout << "Airport found" << endl;
385 wp1_longitude_deg = a.longitude;
386 wp1_latitude_deg = a.latitude;
387 _wp1_name_node->setStringValue(a.name.c_str());
390 else if (waypont_type == "nav") {
392 = globals->get_navlist()->findByIdent(wp1_ID.c_str(),
396 //cout << "Nav found" << endl;
397 wp1_longitude_deg = n->get_lon();
398 wp1_latitude_deg = n->get_lat();
399 _wp1_name_node->setStringValue(n->get_name().c_str());
402 else if (waypont_type == "fix") {
404 if ( globals->get_fixlist()->query(wp1_ID, &f) ) {
405 //cout << "Fix found" << endl;
406 wp1_longitude_deg = f.get_lon();
407 wp1_latitude_deg = f.get_lat();
408 _wp1_name_node->setStringValue(wp1_ID.c_str());
411 _last_wp1_ID = wp1_ID;
416 // If any of the two waypoints have changed
417 // we need to calculate a new course between them,
418 // and values for vertical navigation.
419 if ( wp0_longitude_deg != _wp0_longitude_deg ||
420 wp0_latitude_deg != _wp0_latitude_deg ||
421 wp0_altitude_m != _wp0_altitude_m ||
422 wp1_longitude_deg != _wp1_longitude_deg ||
423 wp1_latitude_deg != _wp1_latitude_deg ||
424 wp1_altitude_m != _wp1_altitude_m )
426 // Update the global variables
427 _wp0_longitude_deg = wp0_longitude_deg;
428 _wp0_latitude_deg = wp0_latitude_deg;
429 _wp0_altitude_m = wp0_altitude_m;
430 _wp1_longitude_deg = wp1_longitude_deg;
431 _wp1_latitude_deg = wp1_latitude_deg;
432 _wp1_altitude_m = wp1_altitude_m;
434 // Get the course and distance from wp0 to wp1
435 SGWayPoint wp0(wp0_longitude_deg,
436 wp0_latitude_deg, wp0_altitude_m);
437 SGWayPoint wp1(wp1_longitude_deg,
438 wp1_latitude_deg, wp1_altitude_m);
440 wp1.CourseAndDistance(wp0, &_course_deg, &_distance_m);
441 double leg_mag_course = _course_deg - magvar_deg;
442 SG_NORMALIZE_RANGE(leg_mag_course, 0.0, 360.0);
444 // Get the altitude / distance ratio
445 if ( distance_m > 0.0 ) {
446 double alt_difference_m = wp0_altitude_m - wp1_altitude_m;
447 _alt_dist_ratio = alt_difference_m / _distance_m;
450 _leg_distance_node->setDoubleValue(_distance_m * SG_METER_TO_NM);
451 _leg_course_node->setDoubleValue(_course_deg);
452 _leg_magnetic_course_node->setDoubleValue(leg_mag_course);
453 _alt_dist_ratio_node->setDoubleValue(_alt_dist_ratio);
455 _wp0_longitude_node->setDoubleValue(wp0_longitude_deg);
456 _wp0_latitude_node->setDoubleValue(wp0_latitude_deg);
457 _wp1_longitude_node->setDoubleValue(wp1_longitude_deg);
458 _wp1_latitude_node->setDoubleValue(wp1_latitude_deg);
462 // Find the bearing and distance to waypoint 0.
463 SGWayPoint wp0(wp0_longitude_deg, wp0_latitude_deg, wp0_altitude_m);
464 wp0.CourseAndDistance(longitude_deg, latitude_deg, altitude_m,
465 &wp0_bearing_deg, &wp0_distance);
466 _wp0_distance_node->setDoubleValue(wp0_distance * SG_METER_TO_NM);
467 _wp0_bearing_node->setDoubleValue(wp0_bearing_deg);
468 double wp0_mag_bearing_deg = wp0_bearing_deg - magvar_deg;
469 SG_NORMALIZE_RANGE(wp0_mag_bearing_deg, 0.0, 360.0);
470 _wp0_mag_bearing_node->setDoubleValue(wp0_mag_bearing_deg);
471 wp0_bearing_error_deg = track1_deg - wp0_bearing_deg;
472 SG_NORMALIZE_RANGE(wp0_bearing_error_deg, -180.0, 180.0);
473 _true_wp0_bearing_error_node->setDoubleValue(wp0_bearing_error_deg);
475 // Estimate time to waypoint 0.
476 // The estimation does not take track into consideration,
477 // so if you are going away from the waypoint the TTW will
478 // increase. Makes most sense when travelling directly towards
480 if (speed_kt > 0.0 && wp0_distance > 0.0) {
481 wp0_TTW = (wp0_distance * SG_METER_TO_NM) / (speed_kt / 3600);
486 unsigned int wp0_TTW_seconds = (int) (wp0_TTW + 0.5);
487 if (wp0_TTW_seconds < 356400) { // That's 99 hours
488 unsigned int wp0_TTW_minutes = 0;
489 unsigned int wp0_TTW_hours = 0;
491 while (wp0_TTW_seconds >= 3600) {
492 wp0_TTW_seconds -= 3600;
495 while (wp0_TTW_seconds >= 60) {
496 wp0_TTW_seconds -= 60;
499 snprintf(wp0_TTW_str, 9, "%02d:%02d:%02d",
500 wp0_TTW_hours, wp0_TTW_minutes, wp0_TTW_seconds);
501 _wp0_ttw_node->setStringValue(wp0_TTW_str);
504 _wp0_ttw_node->setStringValue("--:--:--");
506 // Course deviation is the diffenrence between the bearing
508 wp0_course_deviation_deg = wp0_bearing_deg -
510 SG_NORMALIZE_RANGE(wp0_course_deviation_deg, -180.0, 180.0);
512 // If the course deviation is less than 90 degrees to either side,
513 // our desired course is towards the waypoint.
514 // It does not matter if we are actually moving
515 // towards or from the waypoint.
516 if (fabs(wp0_course_deviation_deg) < 90.0) {
517 _wp0_to_flag_node->setBoolValue(true); }
518 // If it's more than 90 degrees the desired
519 // course is from the waypoint.
520 else if (fabs(wp0_course_deviation_deg) > 90.0) {
521 _wp0_to_flag_node->setBoolValue(false);
522 // When the course is away from the waypoint,
523 // it makes sense to change the sign of the deviation.
524 wp0_course_deviation_deg *= -1.0;
525 SG_NORMALIZE_RANGE(wp0_course_deviation_deg, -90.0, 90.0);
528 _wp0_course_deviation_node->setDoubleValue(wp0_course_deviation_deg);
530 // Cross track error.
531 wp0_course_error_m = sin(wp0_course_deviation_deg * SG_PI / 180.0)
533 _wp0_course_error_nm_node->setDoubleValue(wp0_course_error_m
538 // Find the bearing and distance to waypoint 1.
539 SGWayPoint wp1(wp1_longitude_deg, wp1_latitude_deg, wp1_altitude_m);
540 wp1.CourseAndDistance(longitude_deg, latitude_deg, altitude_m,
541 &wp1_bearing_deg, &wp1_distance);
542 _wp1_distance_node->setDoubleValue(wp1_distance * SG_METER_TO_NM);
543 _wp1_bearing_node->setDoubleValue(wp1_bearing_deg);
544 double wp1_mag_bearing_deg = wp1_bearing_deg - magvar_deg;
545 SG_NORMALIZE_RANGE(wp1_mag_bearing_deg, 0.0, 360.0);
546 _wp1_mag_bearing_node->setDoubleValue(wp1_mag_bearing_deg);
547 wp1_bearing_error_deg = track1_deg - wp1_bearing_deg;
548 SG_NORMALIZE_RANGE(wp1_bearing_error_deg, -180.0, 180.0);
549 _true_wp1_bearing_error_node->setDoubleValue(wp1_bearing_error_deg);
551 // Estimate time to waypoint 1.
552 // The estimation does not take track into consideration,
553 // so if you are going away from the waypoint the TTW will
554 // increase. Makes most sense when travelling directly towards
556 if (speed_kt > 0.0 && wp1_distance > 0.0) {
557 wp1_TTW = (wp1_distance * SG_METER_TO_NM) / (speed_kt / 3600);
562 unsigned int wp1_TTW_seconds = (int) (wp1_TTW + 0.5);
563 if (wp1_TTW_seconds < 356400) { // That's 99 hours
564 unsigned int wp1_TTW_minutes = 0;
565 unsigned int wp1_TTW_hours = 0;
567 while (wp1_TTW_seconds >= 3600) {
568 wp1_TTW_seconds -= 3600;
571 while (wp1_TTW_seconds >= 60) {
572 wp1_TTW_seconds -= 60;
575 snprintf(wp1_TTW_str, 9, "%02d:%02d:%02d",
576 wp1_TTW_hours, wp1_TTW_minutes, wp1_TTW_seconds);
577 _wp1_ttw_node->setStringValue(wp1_TTW_str);
580 _wp1_ttw_node->setStringValue("--:--:--");
582 // Course deviation is the diffenrence between the bearing
584 wp1_course_deviation_deg = wp1_bearing_deg - wp1_course_deg;
585 SG_NORMALIZE_RANGE(wp1_course_deviation_deg, -180.0, 180.0);
587 // If the course deviation is less than 90 degrees to either side,
588 // our desired course is towards the waypoint.
589 // It does not matter if we are actually moving
590 // towards or from the waypoint.
591 if (fabs(wp1_course_deviation_deg) < 90.0) {
592 _wp1_to_flag_node->setBoolValue(true); }
593 // If it's more than 90 degrees the desired
594 // course is from the waypoint.
595 else if (fabs(wp1_course_deviation_deg) > 90.0) {
596 _wp1_to_flag_node->setBoolValue(false);
597 // When the course is away from the waypoint,
598 // it makes sense to change the sign of the deviation.
599 wp1_course_deviation_deg *= -1.0;
600 SG_NORMALIZE_RANGE(wp1_course_deviation_deg, -90.0, 90.0);
603 _wp1_course_deviation_node->setDoubleValue(wp1_course_deviation_deg);
605 // Cross track error.
606 wp1_course_error_m = sin(wp1_course_deviation_deg * SG_PI / 180.0)
608 _wp1_course_error_nm_node->setDoubleValue(wp1_course_error_m
612 // Leg course deviation is the diffenrence between the bearing
614 double course_deviation_deg = wp1_bearing_deg - _course_deg;
615 SG_NORMALIZE_RANGE(course_deviation_deg, -180.0, 180.0);
617 // If the course deviation is less than 90 degrees to either side,
618 // our desired course is towards the waypoint.
619 // It does not matter if we are actually moving
620 // towards or from the waypoint.
621 if (fabs(course_deviation_deg) < 90.0) {
622 _leg_to_flag_node->setBoolValue(true); }
623 // If it's more than 90 degrees the desired
624 // course is from the waypoint.
625 else if (fabs(course_deviation_deg) > 90.0) {
626 _leg_to_flag_node->setBoolValue(false);
627 // When the course is away from the waypoint,
628 // it makes sense to change the sign of the deviation.
629 course_deviation_deg *= -1.0;
630 SG_NORMALIZE_RANGE(course_deviation_deg, -90.0, 90.0);
633 _leg_course_deviation_node->setDoubleValue(course_deviation_deg);
635 // Cross track error.
636 double course_error_m = sin(course_deviation_deg * SG_PI / 180.0)
638 _leg_course_error_nm_node->setDoubleValue(course_error_m * SG_METER_TO_NM);
640 // Altitude deviation
641 double desired_altitude_m = wp1_altitude_m
642 + wp1_distance * _alt_dist_ratio;
643 double altitude_deviation_m = altitude_m - desired_altitude_m;
644 _alt_deviation_node->setDoubleValue(altitude_deviation_m * SG_METER_TO_FEET);
649 double tracking_bug = _tracking_bug_node->getDoubleValue();
650 double true_bug_error = tracking_bug - track1_deg;
651 double magnetic_bug_error = tracking_bug - mag_track_bearing;
653 // Get the errors into the (-180,180) range.
654 SG_NORMALIZE_RANGE(true_bug_error, -180.0, 180.0);
655 SG_NORMALIZE_RANGE(magnetic_bug_error, -180.0, 180.0);
657 _true_bug_error_node->setDoubleValue(true_bug_error);
658 _magnetic_bug_error_node->setDoubleValue(magnetic_bug_error);
661 // Add WP 1 to the route.
662 if ( addWp->getBoolValue() )
664 addWp->setBoolValue(false);
666 SGWayPoint tempWp( _wp1_longitude_node->getDoubleValue(),
667 _wp1_latitude_node->getDoubleValue(),
668 _wp1_altitude_node->getDoubleValue(),
670 _wp1_ID_node->getStringValue(),
671 _wp1_name_node->getStringValue() );
673 route->add_waypoint(tempWp);
676 _route->getChild("Waypoint", route->size()-1, true);
677 SGPropertyNode *id = wp->getChild("ID", 0, true);
678 SGPropertyNode *name = wp->getChild("Name", 0, true);
679 SGPropertyNode *lat = wp->getChild("Latitude", 0, true);
680 SGPropertyNode *lon = wp->getChild("Longitude", 0, true);
681 SGPropertyNode *alt = wp->getChild("Altitude", 0, true);
683 id->setStringValue( tempWp.get_id().c_str() );
684 name->setStringValue( tempWp.get_name().c_str() );
685 lat->setDoubleValue( tempWp.get_target_lat() );
686 lon->setDoubleValue( tempWp.get_target_lon() );
687 alt->setDoubleValue( tempWp.get_target_alt() );
690 if ( popWp->getBoolValue() )
692 popWp->setBoolValue(false);
694 route->delete_first();
698 _true_track_node->setDoubleValue(0.0);
699 _magnetic_track_node->setDoubleValue(0.0);
700 _speed_node->setDoubleValue(0.0);
704 _last_longitude_deg = longitude_deg;
705 _last_latitude_deg = latitude_deg;
706 _last_altitude_m = altitude_m;