1 // tacan.cxx - Tactical Navigation Beacon.
2 // Written by Vivian Meazaa, started 2005.
4 // This file is in the Public Domain and comes with no warranty.
10 #include <simgear/compiler.h>
11 #include <simgear/math/sg_geodesy.hxx>
12 #include <simgear/math/sg_random.h>
14 #include <Main/fg_props.hxx>
15 #include <Navaids/navlist.hxx>
26 * Start by calculating the radar horizon based on the elevation
27 * difference, then clamp to the maximum, then add a fudge for
28 * borderline reception.
31 adjust_range (double transmitter_elevation_ft, double aircraft_altitude_ft,
35 double delta_elevation_ft =
36 fabs(aircraft_altitude_ft - transmitter_elevation_ft);
37 double range_nm = 1.23 * sqrt(delta_elevation_ft);
38 if (range_nm > max_range_nm)
39 range_nm = max_range_nm;
40 else if (range_nm < 20.0)
42 double rand = sg_random();
43 SG_LOG( SG_INSTR, SG_DEBUG, " tacan range " << range_nm << " max range " << max_range_nm);
44 return range_nm + (range_nm * rand * rand);
48 TACAN::TACAN ( SGPropertyNode *node )
49 : _last_distance_nm(0),
50 _last_frequency_mhz(-1),
51 _time_before_search_sec(0),
52 _carrier_valid(false),
53 _transmitter_valid(false),
54 _transmitter_elevation_ft(0),
55 _transmitter_range_nm(0),
56 _transmitter_bias(0.0),
63 for ( i = 0; i < node->nChildren(); ++i ) {
64 SGPropertyNode *child = node->getChild(i);
65 string cname = child->getName();
66 string cval = child->getStringValue();
67 if ( cname == "name" ) {
69 } else if ( cname == "number" ) {
70 num = child->getIntValue();
72 SG_LOG( SG_INSTR, SG_DEBUG, "Error in TACAN config logic" );
73 if ( name.length() ) {
74 SG_LOG( SG_INSTR, SG_DEBUG, "Section = " << name );
81 : _last_distance_nm(0),
82 _last_frequency_mhz(-1),
83 _time_before_search_sec(0),
84 _carrier_valid(false),
85 _transmitter_valid(false),
86 _transmitter_elevation_ft(0),
87 _transmitter_range_nm(0),
88 _transmitter_bearing_deg(0),
89 _transmitter_bias(0.0),
90 _transmitter_name(""),
103 branch = "/instrumentation/" + name;
105 SGPropertyNode *node = fgGetNode(branch.c_str(), num, true );
107 _longitude_node = fgGetNode("/position/longitude-deg", true);
108 _latitude_node = fgGetNode("/position/latitude-deg", true);
109 _altitude_node = fgGetNode("/position/altitude-ft", true);
110 _heading_node = fgGetNode("/orientation/heading-deg", true);
111 _yaw_node = fgGetNode("/orientation/side-slip-deg", true);
112 _serviceable_node = node->getChild("serviceable", 0, true);
113 _electrical_node = fgGetNode("/systems/electrical/outputs/tacan", true);
114 SGPropertyNode *fnode = node->getChild("frequencies", 0, true);
115 _source_node = fnode->getChild("source", 0, true);
116 _frequency_node = fnode->getChild("selected-mhz", 0, true);
117 _channel_node = fnode->getChild("selected-channel", 1, true);
118 _channel_node = fnode->getChild("selected-channel", 2, true);
119 _channel_node = fnode->getChild("selected-channel", 3, true);
120 _channel_node = fnode->getChild("selected-channel", 4, true);
121 _in_range_node = node->getChild("in-range", 0, true);
122 _distance_node = node->getChild("indicated-distance-nm", 0, true);
123 _speed_node = node->getChild("indicated-ground-speed-kt", 0, true);
124 _time_node = node->getChild("indicated-time-min", 0, true);
125 _name_node = node->getChild("name", 0, true);
126 _bearing_node = node->getChild("indicated-bearing-true-deg", 0, true);
127 SGPropertyNode *dnode = node->getChild("display", 0, true);
128 _x_shift_node = dnode->getChild("x-shift", 0, true);
129 _y_shift_node = dnode->getChild("y-shift", 0, true);
130 _rotation_node = dnode->getChild("rotation", 0, true);
131 _channel_node = dnode->getChild("channel", 0, true);
133 SGPropertyNode *cnode = fgGetNode("/ai/models/carrier", num, false );
135 _carrier_name_node = cnode->getChild("name", 0, false);
137 SGPropertyNode *tnode = fgGetNode("/ai/models/aircraft", num, false);
139 _tanker_callsign_node = tnode->getChild("callsign", 0, false);
141 SGPropertyNode *mnode = fgGetNode("/ai/models/multiplayer", num, false);
143 _mp_callsign_node = mnode->getChild("callsign", 0, false);
147 TACAN::update (double delta_time_sec)
152 double carrier_az2 = 0;
153 double carrier_bearing = 0;
154 double carrier_distance = 0;
155 double tanker_az2 = 0;
156 double tanker_bearing = 0;
157 double tanker_distance = 0;
158 double frequency_mhz = 0;
159 double mobile_bearing = 0;
160 double mobile_distance = 0;
161 double mobile_elevation_ft = 0;
162 double mobile_range_nm = 0;
163 double mobile_bias = 0;
164 string mobile_name = "";
165 bool mobile_valid = false;
167 string _channel, _last_channel, _channel_1, _channel_2,_channel_3, _channel_4;
169 // If it's off, don't waste any time.
170 if (!_serviceable_node->getBoolValue() || !_electrical_node->getBoolValue()) {
171 _last_distance_nm = 0;
172 _in_range_node->setBoolValue(false);
173 _distance_node->setDoubleValue(0);
174 _speed_node->setDoubleValue(0);
175 _time_node->setDoubleValue(0);
176 SG_LOG( SG_INSTR, SG_DEBUG, "skip tacan" );
180 // Figure out the source
181 const char * source = _source_node->getStringValue();
183 if (source[0] == '\0') {
185 branch = "/instrumentation/" + name + "/frequencies/selected-channel";
186 _source_node->setStringValue(branch.c_str());
187 source = _source_node->getStringValue();
188 SG_LOG( SG_INSTR, SG_DEBUG, "source " << source );
191 _channel_1 = fgGetString("/instrumentation/tacan/frequencies/selected-channel[1]");
192 _channel_2 = fgGetString("/instrumentation/tacan/frequencies/selected-channel[2]");
193 _channel_3 = fgGetString("/instrumentation/tacan/frequencies/selected-channel[3]");
194 _channel_4 = fgGetString("/instrumentation/tacan/frequencies/selected-channel[4]");
196 SG_LOG( SG_INSTR, SG_DEBUG, "channels " << _channel_1 << _channel_2 << _channel_3 << _channel_4);
198 _channel = _channel_1 + _channel_2 + _channel_3 + _channel_4;
201 if (_channel != _last_channel) {
202 _time_before_search_sec = 0;
203 _last_channel = _channel;
204 frequency_mhz = searchChannel(_channel);
205 SG_LOG( SG_INSTR, SG_DEBUG, "frequency " << frequency_mhz );
206 _frequency_node->setDoubleValue(frequency_mhz);
209 SG_LOG( SG_INSTR, SG_DEBUG, "channel " << _channel );
210 // Get the aircraft position
211 double longitude_deg = _longitude_node->getDoubleValue();
212 double latitude_deg = _latitude_node->getDoubleValue();
213 double altitude_m = _altitude_node->getDoubleValue() * SG_FEET_TO_METER;
214 double heading = _heading_node->getDoubleValue() ;
215 double yaw = _yaw_node->getDoubleValue() ;
216 double longitude_rad = longitude_deg * SGD_DEGREES_TO_RADIANS;
217 double latitude_rad = latitude_deg * SGD_DEGREES_TO_RADIANS;
219 // On timeout, scan again
220 _time_before_search_sec -= delta_time_sec;
221 if (_time_before_search_sec < 0 && frequency_mhz >= 0)
222 search(frequency_mhz, longitude_rad, latitude_rad, altitude_m);
224 // Calculate the distance to the transmitter
226 //calculate the bearing and range of the carrier from the aircraft
227 SG_LOG( SG_INSTR, SG_DEBUG, "carrier_lat " << _carrier_lat);
228 SG_LOG( SG_INSTR, SG_DEBUG, "carrier_lon " << _carrier_lon);
229 SG_LOG( SG_INSTR, SG_DEBUG, "carrier_name " << _carrier_name);
230 SG_LOG( SG_INSTR, SG_DEBUG, "carrier_valid " << _carrier_valid);
231 geo_inverse_wgs_84(altitude_m,
236 &carrier_bearing, &carrier_az2, &carrier_distance);
238 //calculate the bearing and range of the tanker from the aircraft
239 SG_LOG( SG_INSTR, SG_DEBUG, "tanker_lat " << _tanker_lat);
240 SG_LOG( SG_INSTR, SG_DEBUG, "tanker_lon " << _tanker_lon);
241 SG_LOG( SG_INSTR, SG_DEBUG, "tanker_name " << _tanker_name);
242 SG_LOG( SG_INSTR, SG_DEBUG, "tanker_valid " << _tanker_valid);
243 geo_inverse_wgs_84(altitude_m,
248 &tanker_bearing, &tanker_az2, &tanker_distance);
251 //calculate the bearing and range of the station from the aircraft
252 geo_inverse_wgs_84(altitude_m,
257 &bearing, &az2, &distance);
259 //select the nearest valid mobile transmitter
260 if ( _carrier_valid && (_tanker_valid || _mp_tanker_valid ) ) {
261 if( carrier_distance <= tanker_distance ){
262 SG_LOG( SG_INSTR, SG_DEBUG, " select carrier (dist) " );
263 mobile_bearing = carrier_bearing;
264 mobile_distance = carrier_distance;
265 mobile_elevation_ft = _carrier_elevation_ft;
266 mobile_range_nm = _carrier_range_nm;
267 mobile_bias = _carrier_bias;
268 mobile_name = _carrier_name;
270 SG_LOG( SG_INSTR, SG_DEBUG, " select tanker (dist) " );
271 mobile_bearing = tanker_bearing;
272 mobile_distance = tanker_distance;
273 mobile_elevation_ft = _tanker_elevation_ft;
274 mobile_range_nm = _tanker_range_nm;
275 mobile_bias = _tanker_bias;
276 mobile_name = _tanker_name;
280 else if ( _carrier_valid && (!_tanker_valid || _mp_tanker_valid) ) {
281 SG_LOG( SG_INSTR, SG_DEBUG, " select carrier " );
282 mobile_bearing = carrier_bearing;
283 mobile_distance = carrier_distance;
284 mobile_elevation_ft = _carrier_elevation_ft;
285 mobile_range_nm = _carrier_range_nm;
286 mobile_bias = _carrier_bias;
287 mobile_name = _carrier_name;
290 else if ( !_carrier_valid && (_tanker_valid || _mp_tanker_valid ) ) {
291 SG_LOG( SG_INSTR, SG_DEBUG, " select tanker " );
292 mobile_bearing = tanker_bearing;
293 mobile_distance = tanker_distance;
294 mobile_elevation_ft = _tanker_elevation_ft;
295 mobile_range_nm = _tanker_range_nm;
296 mobile_bias = _tanker_bias;
297 mobile_name = _tanker_name;
300 mobile_valid = false;
307 if ( mobile_distance <= distance && mobile_valid) {
308 SG_LOG( SG_INSTR, SG_DEBUG, "mobile_distance_m " << mobile_distance);
309 SG_LOG( SG_INSTR, SG_DEBUG, "distance_m " << distance);
310 bearing = mobile_bearing;
311 distance = mobile_distance;
312 _transmitter_elevation_ft = mobile_elevation_ft;
313 _transmitter_range_nm = mobile_range_nm;
314 _transmitter_bias = mobile_bias;
315 _transmitter_name = mobile_name;
316 _name_node->setStringValue(_transmitter_name.c_str());
317 _channel_node->setStringValue(_channel.c_str());
320 //// calculate some values for boresight display
321 double distance_nm = distance * SG_METER_TO_NM;
323 //// calculate look left/right to target, without yaw correction
324 // double horiz_offset = bearing - heading;
326 // if (horiz_offset > 180.0) horiz_offset -= 360.0;
327 // if (horiz_offset < -180.0) horiz_offset += 360.0;
329 //// now correct look left/right for yaw
330 // horiz_offset += yaw;
332 // use the bearing for plan position indicator display
334 double horiz_offset = bearing;
336 SG_LOG( SG_INSTR, SG_DEBUG, "distance_nm " << distance_nm << " bearing "
337 << bearing << " horiz_offset " << horiz_offset);
339 // calculate values for radar display
340 double y_shift = distance_nm * cos( horiz_offset * SG_DEGREES_TO_RADIANS);
341 double x_shift = distance_nm * sin( horiz_offset * SG_DEGREES_TO_RADIANS);
343 SG_LOG( SG_INSTR, SG_DEBUG, "y_shift " << y_shift << " x_shift " << x_shift);
348 sgGeodToCart(Point3D(longitude_rad, latitude_rad, altitude_m));
349 double distance_nm = _transmitter.distance3D(location) * SG_METER_TO_NM;*/
351 double range_nm = adjust_range(_transmitter_elevation_ft,
352 altitude_m * SG_METER_TO_FEET,
353 _transmitter_range_nm);
355 if (distance_nm <= range_nm) {
356 double speed_kt = (fabs(distance_nm - _last_distance_nm) *
357 ((1 / delta_time_sec) * 3600.0));
358 _last_distance_nm = distance_nm;
360 _in_range_node->setBoolValue(true);
361 double tmp_dist = distance_nm - _transmitter_bias;
362 if ( tmp_dist < 0.0 ) {
365 _distance_node->setDoubleValue( tmp_dist );
366 _speed_node->setDoubleValue(speed_kt);
367 _time_node->setDoubleValue(distance_nm/speed_kt*60.0);
368 _bearing_node->setDoubleValue(bearing);
369 _x_shift_node->setDoubleValue(x_shift);
370 _y_shift_node->setDoubleValue(y_shift);
371 _rotation_node->setDoubleValue(rotation);
373 _last_distance_nm = 0;
374 _in_range_node->setBoolValue(false);
375 _distance_node->setDoubleValue(0);
376 _speed_node->setDoubleValue(0);
377 _time_node->setDoubleValue(0);
378 _bearing_node->setDoubleValue(0);
379 _x_shift_node->setDoubleValue(0);
380 _y_shift_node->setDoubleValue(0);
381 _rotation_node->setDoubleValue(0);
384 // If we can't find a valid station set everything to zero
385 if (!_transmitter_valid && !mobile_valid ) {
386 _in_range_node->setBoolValue(false);
387 _distance_node->setDoubleValue(0);
388 _speed_node->setDoubleValue(0);
389 _time_node->setDoubleValue(0);
390 _bearing_node->setDoubleValue(0);
391 _x_shift_node->setDoubleValue(0);
392 _y_shift_node->setDoubleValue(0);
393 _rotation_node->setDoubleValue(0);
394 _transmitter_name = "";
395 _name_node->setStringValue(_transmitter_name.c_str());
396 _channel_node->setStringValue(_channel.c_str());
399 } // end function update
402 TACAN::search (double frequency_mhz, double longitude_rad,
403 double latitude_rad, double altitude_m)
407 SG_LOG( SG_INSTR, SG_DEBUG, "tacan freq " << frequency_mhz );
410 _time_before_search_sec = 1.0;
412 //try any carriers first
413 FGNavRecord *carrier_tacan
414 = globals->get_carrierlist()->findStationByFreq( frequency_mhz );
415 _carrier_valid = (carrier_tacan != NULL);
417 if ( _carrier_valid ) {
418 SG_LOG( SG_INSTR, SG_DEBUG, "carrier transmitter valid " << _carrier_valid );
420 string str1( carrier_tacan->get_name() );
422 SGPropertyNode * branch = fgGetNode("ai/models", true);
423 vector<SGPropertyNode_ptr> carrier = branch->getChildren("carrier");
425 number = carrier.size();
427 SG_LOG( SG_INSTR, SG_DEBUG, "carrier " << number );
429 for ( i = 0; i < number; ++i ) {
430 string str2 ( carrier[i]->getStringValue("name", ""));
431 SG_LOG( SG_INSTR, SG_DEBUG, "carrier name " << str2 );
433 SG_LOG( SG_INSTR, SG_DEBUG, "strings 1 " << str1 << " 2 " << str2 );
434 unsigned int loc1= str1.find( str2, 0 );
435 if ( loc1 != string::npos && str2 != "" ) {
436 SG_LOG( SG_INSTR, SG_DEBUG, " string found" );
437 _carrier_lat = carrier[i]->getDoubleValue("position/latitude-deg");
438 _carrier_lon = carrier[i]->getDoubleValue("position/longitude-deg");
439 _carrier_elevation_ft = carrier_tacan->get_elev_ft();
440 _carrier_range_nm = carrier_tacan->get_range();
441 _carrier_bias = carrier_tacan->get_multiuse();
442 _carrier_name = carrier_tacan->get_name();
444 SG_LOG( SG_INSTR, SG_DEBUG, " carrier transmitter valid " << _carrier_valid );
448 SG_LOG( SG_INSTR, SG_DEBUG, " carrier transmitter invalid " << _carrier_valid );
452 SG_LOG( SG_INSTR, SG_DEBUG, "name " << _carrier_name);
453 SG_LOG( SG_INSTR, SG_DEBUG, "lat " << _carrier_lat << "lon " << _carrier_lon);
454 SG_LOG( SG_INSTR, SG_DEBUG, "elev " << _carrier_elevation_ft);
457 SG_LOG( SG_INSTR, SG_DEBUG, " carrier transmitter invalid " << _carrier_valid );
460 //try any tankers second
461 FGNavRecord *tanker_tacan
462 = globals->get_carrierlist()->findStationByFreq( frequency_mhz );
464 _tanker_valid = (tanker_tacan != NULL);
467 if ( _tanker_valid ) {
468 SG_LOG( SG_INSTR, SG_DEBUG, "tanker transmitter valid start " << _tanker_valid );
470 string str3( tanker_tacan->get_name() );
472 SGPropertyNode * branch = fgGetNode("ai/models", true);
473 vector<SGPropertyNode_ptr> tanker = branch->getChildren("aircraft");
475 number = tanker.size();
477 SG_LOG( SG_INSTR, SG_DEBUG, "tanker number " << number );
479 for ( i = 0; i < number; ++i ) {
480 string str4 ( tanker[i]->getStringValue("callsign", ""));
481 SG_LOG( SG_INSTR, SG_DEBUG, "tanker callsign " << str4 );
483 SG_LOG( SG_INSTR, SG_DEBUG, "strings 3 " << str3 << " 4 " << str4 );
484 unsigned int loc1= str3.find( str4, 0 );
485 if ( loc1 != string::npos && str4 != "" ) {
486 SG_LOG( SG_INSTR, SG_DEBUG, " string found" );
487 _tanker_lat = tanker[i]->getDoubleValue("position/latitude-deg");
488 _tanker_lon = tanker[i]->getDoubleValue("position/longitude-deg");
489 _tanker_elevation_ft = tanker[i]->getDoubleValue("position/altitude-ft");
490 _tanker_range_nm = tanker_tacan->get_range();
491 _tanker_bias = tanker_tacan->get_multiuse();
492 _tanker_name = tanker_tacan->get_name();
494 SG_LOG( SG_INSTR, SG_DEBUG, " tanker transmitter valid " << _tanker_valid );
498 SG_LOG( SG_INSTR, SG_DEBUG, " tanker transmitter invalid " << _tanker_valid );
502 SG_LOG( SG_INSTR, SG_DEBUG, "tanker name " << _tanker_name);
503 SG_LOG( SG_INSTR, SG_DEBUG, "lat " << _tanker_lat << "lon " << _tanker_lon);
504 SG_LOG( SG_INSTR, SG_DEBUG, "elev " << _tanker_elevation_ft);
505 SG_LOG( SG_INSTR, SG_DEBUG, "range " << _tanker_range_nm);
508 SG_LOG( SG_INSTR, SG_DEBUG, " tanker transmitter invalid " << _tanker_valid );
511 //try any mp tankers third, if we haven't found the tanker in the ai aircraft
512 FGNavRecord *mp_tanker_tacan
513 = globals->get_carrierlist()->findStationByFreq( frequency_mhz );
515 _mp_tanker_valid = (mp_tanker_tacan != NULL);
518 if ( _mp_tanker_valid && ! _tanker_valid ) {
519 SG_LOG( SG_INSTR, SG_DEBUG, " mp tanker transmitter valid start " << _mp_tanker_valid );
521 string str5( mp_tanker_tacan->get_name() );
523 SGPropertyNode * branch = fgGetNode("ai/models", true);
524 vector<SGPropertyNode_ptr> mp_tanker = branch->getChildren("multiplayer");
526 number = mp_tanker.size();
528 SG_LOG( SG_INSTR, SG_DEBUG, " mp tanker number " << number );
530 for ( i = 0; i < number; ++i ) {
531 string str6 ( mp_tanker[i]->getStringValue("callsign", ""));
532 SG_LOG( SG_INSTR, SG_DEBUG, "mp tanker callsign " << str6 );
534 SG_LOG( SG_INSTR, SG_DEBUG, "strings 5 " << str5 << " 5 " << str6 );
535 unsigned int loc1= str5.find( str6, 0 );
536 if ( loc1 != string::npos && str6 != "" ) {
537 SG_LOG( SG_INSTR, SG_DEBUG, " string found" );
538 _tanker_lat = mp_tanker[i]->getDoubleValue("position/latitude-deg");
539 _tanker_lon = mp_tanker[i]->getDoubleValue("position/longitude-deg");
540 _tanker_elevation_ft = mp_tanker[i]->getDoubleValue("position/altitude-ft");
541 _tanker_range_nm = mp_tanker_tacan->get_range();
542 _tanker_bias = mp_tanker_tacan->get_multiuse();
543 _tanker_name = mp_tanker_tacan->get_name();
544 _mp_tanker_valid = 1;
546 SG_LOG( SG_INSTR, SG_DEBUG, " mp tanker transmitter valid " << _mp_tanker_valid );
547 SG_LOG( SG_INSTR, SG_DEBUG, "mp_tanker name " << _tanker_name);
548 SG_LOG( SG_INSTR, SG_DEBUG, "lat " << _tanker_lat << "lon " << _tanker_lon);
549 SG_LOG( SG_INSTR, SG_DEBUG, "elev " << _tanker_elevation_ft);
550 SG_LOG( SG_INSTR, SG_DEBUG, "range " << _tanker_range_nm);
553 _mp_tanker_valid = 0;
554 SG_LOG( SG_INSTR, SG_DEBUG, " tanker transmitter invalid " << _mp_tanker_valid );
561 SG_LOG( SG_INSTR, SG_DEBUG, " tanker transmitter invalid " << _tanker_valid );
563 // try the TACAN/VORTAC list next
565 = globals->get_tacanlist()->findByFreq( frequency_mhz, longitude_rad,
566 latitude_rad, altitude_m);
568 _transmitter_valid = (tacan != NULL);
570 if ( _transmitter_valid ) {
571 SG_LOG( SG_INSTR, SG_DEBUG, "transmitter valid " << _transmitter_valid );
573 _transmitter_lat = tacan->get_lat();
574 _transmitter_lon = tacan->get_lon();
575 _transmitter_elevation_ft = tacan->get_elev_ft();
576 _transmitter_range_nm = tacan->get_range();
577 _transmitter_bias = tacan->get_multiuse();
578 _transmitter_name = tacan->get_name();
579 _name_node->setStringValue(_transmitter_name.c_str());
581 SG_LOG( SG_INSTR, SG_DEBUG, "name " << _transmitter_name);
582 SG_LOG( SG_INSTR, SG_DEBUG, "lat " << _transmitter_lat << "lon " << _transmitter_lon);
583 SG_LOG( SG_INSTR, SG_DEBUG, "elev " << _transmitter_elevation_ft);
586 SG_LOG( SG_INSTR, SG_DEBUG, "transmitter invalid " << _transmitter_valid );
591 TACAN::searchChannel (const string& _channel){
593 double frequency_khz = 0;
596 = globals->get_channellist()->findByChannel( _channel );
597 double _freq_valid = (freq != NULL);
598 SG_LOG( SG_INSTR, SG_DEBUG, "freq valid " << _freq_valid );
600 frequency_khz = freq->get_freq();
601 SG_LOG( SG_INSTR, SG_DEBUG, "freq output " << frequency_khz );
603 if (frequency_khz >=9620 && frequency_khz <= 12130)
604 return frequency_khz/100;
606 return frequency_khz = 0;
607 } // end TACAN::searchChannel