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 _serviceable_node = node->getChild("serviceable", 0, true);
111 _electrical_node = fgGetNode("/systems/electrical/outputs/tacan", true);
112 SGPropertyNode *fnode = node->getChild("frequencies", 0, true);
113 _source_node = fnode->getChild("source", 0, true);
114 _frequency_node = fnode->getChild("selected-mhz", 0, true);
115 _channel_node = fnode->getChild("selected-channel", 1, true);
116 _channel_node = fnode->getChild("selected-channel", 2, true);
117 _channel_node = fnode->getChild("selected-channel", 3, true);
118 _channel_node = fnode->getChild("selected-channel", 4, true);
119 _in_range_node = node->getChild("in-range", 0, true);
120 _distance_node = node->getChild("indicated-distance-nm", 0, true);
121 _speed_node = node->getChild("indicated-ground-speed-kt", 0, true);
122 _time_node = node->getChild("indicated-time-min", 0, true);
123 _name_node = node->getChild("name", 0, true);
124 _bearing_node = node->getChild("indicated-bearing-true-deg", 0, true);
125 SGPropertyNode *cnode = fgGetNode("/ai/models/carrier", num, true );
126 _carrier_name_node = cnode->getChild("name", 0, true);
127 SGPropertyNode *tnode = fgGetNode("/ai/models/aircraft", num, true );
128 _tanker_callsign_node = tnode->getChild("callsign", 0, true);
132 TACAN::update (double delta_time_sec)
137 double carrier_az2 = 0;
138 double carrier_bearing = 0;
139 double carrier_distance = 0;
140 double tanker_az2 = 0;
141 double tanker_bearing = 0;
142 double tanker_distance = 0;
143 double frequency_mhz = 0;
144 double mobile_bearing = 0;
145 double mobile_distance = 0;
146 double mobile_elevation_ft = 0;
147 double mobile_range_nm = 0;
148 double mobile_bias = 0;
149 string mobile_name = "";
150 bool mobile_valid = false;
152 string _channel, _last_channel, _channel_1, _channel_2,_channel_3, _channel_4;
154 // If it's off, don't waste any time.
155 if (!_serviceable_node->getBoolValue() || !_electrical_node->getBoolValue()) {
156 _last_distance_nm = 0;
157 _in_range_node->setBoolValue(false);
158 _distance_node->setDoubleValue(0);
159 _speed_node->setDoubleValue(0);
160 _time_node->setDoubleValue(0);
161 SG_LOG( SG_INSTR, SG_DEBUG, "skip tacan" );
165 // Figure out the source
166 const char * source = _source_node->getStringValue();
168 if (source[0] == '\0') {
170 branch = "/instrumentation/" + name + "/frequencies/selected-channel";
171 _source_node->setStringValue(branch.c_str());
172 source = _source_node->getStringValue();
173 SG_LOG( SG_INSTR, SG_DEBUG, "source " << source );
176 _channel_1 = fgGetString("/instrumentation/tacan/frequencies/selected-channel[1]");
177 _channel_2 = fgGetString("/instrumentation/tacan/frequencies/selected-channel[2]");
178 _channel_3 = fgGetString("/instrumentation/tacan/frequencies/selected-channel[3]");
179 _channel_4 = fgGetString("/instrumentation/tacan/frequencies/selected-channel[4]");
180 SG_LOG( SG_INSTR, SG_DEBUG, "channels " << _channel_1 << _channel_2 << _channel_3 << _channel_4);
181 _channel = _channel_1 + _channel_2 + _channel_3 + _channel_4;
182 SG_LOG( SG_INSTR, SG_DEBUG, "channel " << _channel );
184 // Get the frequecncy
185 if (_channel != _last_channel) {
186 _time_before_search_sec = 0;
187 _last_channel = _channel;
188 frequency_mhz = searchChannel(_channel);
189 SG_LOG( SG_INSTR, SG_DEBUG, "frequency " << frequency_mhz );
190 _frequency_node->setDoubleValue(frequency_mhz);
193 // Get the aircraft position
194 double longitude_deg = _longitude_node->getDoubleValue();
195 double latitude_deg = _latitude_node->getDoubleValue();
196 double altitude_m = _altitude_node->getDoubleValue() * SG_FEET_TO_METER;
197 double longitude_rad = longitude_deg * SGD_DEGREES_TO_RADIANS;
198 double latitude_rad = latitude_deg * SGD_DEGREES_TO_RADIANS;
200 // On timeout, scan again
201 _time_before_search_sec -= delta_time_sec;
202 if (_time_before_search_sec < 0 && frequency_mhz > 0)
203 search(frequency_mhz, longitude_rad, latitude_rad, altitude_m);
205 // Calculate the distance to the transmitter
207 //calculate the bearing and range of the carrier from the aircraft
208 SG_LOG( SG_INSTR, SG_DEBUG, "carrier_lat " << _carrier_lat);
209 SG_LOG( SG_INSTR, SG_DEBUG, "carrier_lon " << _carrier_lon);
210 SG_LOG( SG_INSTR, SG_DEBUG, "carrier_name " << _carrier_name);
211 SG_LOG( SG_INSTR, SG_DEBUG, "carrier_valid " << _carrier_valid);
212 geo_inverse_wgs_84(altitude_m,
217 &carrier_bearing, &carrier_az2, &carrier_distance);
219 //calculate the bearing and range of the tanker from the aircraft
220 SG_LOG( SG_INSTR, SG_DEBUG, "tanker_lat " << _tanker_lat);
221 SG_LOG( SG_INSTR, SG_DEBUG, "tanker_lon " << _tanker_lon);
222 SG_LOG( SG_INSTR, SG_DEBUG, "tanker_name " << _tanker_name);
223 SG_LOG( SG_INSTR, SG_DEBUG, "tanker_valid " << _tanker_valid);
224 geo_inverse_wgs_84(altitude_m,
229 &tanker_bearing, &tanker_az2, &tanker_distance);
232 //calculate the bearing and range of the station from the aircraft
233 geo_inverse_wgs_84(altitude_m,
238 &bearing, &az2, &distance);
240 //select the nearest valid mobile transmitter
241 if ( _carrier_valid && _tanker_valid ){
242 if( carrier_distance <= tanker_distance ){
243 SG_LOG( SG_INSTR, SG_DEBUG, " select carrier (dist) " );
244 mobile_bearing = carrier_bearing;
245 mobile_distance = carrier_distance;
246 mobile_elevation_ft = _carrier_elevation_ft;
247 mobile_range_nm = _carrier_range_nm;
248 mobile_bias = _carrier_bias;
249 mobile_name = _carrier_name;
251 SG_LOG( SG_INSTR, SG_DEBUG, " select tanker (dist) " );
252 mobile_bearing = tanker_bearing;
253 mobile_distance = tanker_distance;
254 mobile_elevation_ft = _tanker_elevation_ft;
255 mobile_range_nm = _tanker_range_nm;
256 mobile_bias = _tanker_bias;
257 mobile_name = _tanker_name;
261 else if ( _carrier_valid && !_tanker_valid ){
262 SG_LOG( SG_INSTR, SG_DEBUG, " select carrier " );
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;
271 else if ( !_carrier_valid && _tanker_valid ){
272 SG_LOG( SG_INSTR, SG_DEBUG, " select tanker " );
273 mobile_bearing = tanker_bearing;
274 mobile_distance = tanker_distance;
275 mobile_elevation_ft = _tanker_elevation_ft;
276 mobile_range_nm = _tanker_range_nm;
277 mobile_bias = _tanker_bias;
278 mobile_name = _tanker_name;
281 mobile_valid = false;
288 if ( mobile_distance <= distance && mobile_valid) {
289 SG_LOG( SG_INSTR, SG_DEBUG, "mobile_distance_m " << mobile_distance);
290 SG_LOG( SG_INSTR, SG_DEBUG, "distance_m " << distance);
291 bearing = mobile_bearing;
292 distance = mobile_distance;
293 _transmitter_elevation_ft = mobile_elevation_ft;
294 _transmitter_range_nm = mobile_range_nm;
295 _transmitter_bias = mobile_bias;
296 _transmitter_name = mobile_name;
297 _name_node->setStringValue(_transmitter_name.c_str());
300 double distance_nm = distance * SG_METER_TO_NM;
301 SG_LOG( SG_INSTR, SG_DEBUG, "distance_nm " << distance_nm << " bearing " << bearing);
304 sgGeodToCart(Point3D(longitude_rad, latitude_rad, altitude_m));
305 double distance_nm = _transmitter.distance3D(location) * SG_METER_TO_NM;*/
307 double range_nm = adjust_range(_transmitter_elevation_ft,
308 altitude_m * SG_METER_TO_FEET,
309 _transmitter_range_nm);
311 if (distance_nm <= range_nm) {
312 double speed_kt = (fabs(distance_nm - _last_distance_nm) *
313 ((1 / delta_time_sec) * 3600.0));
314 _last_distance_nm = distance_nm;
316 _in_range_node->setBoolValue(true);
317 double tmp_dist = distance_nm - _transmitter_bias;
318 if ( tmp_dist < 0.0 ) {
321 _distance_node->setDoubleValue( tmp_dist );
322 _speed_node->setDoubleValue(speed_kt);
323 _time_node->setDoubleValue(distance_nm/speed_kt*60.0);
324 _bearing_node->setDoubleValue(bearing);
327 _last_distance_nm = 0;
328 _in_range_node->setBoolValue(false);
329 _distance_node->setDoubleValue(0);
330 _speed_node->setDoubleValue(0);
331 _time_node->setDoubleValue(0);
332 _bearing_node->setDoubleValue(0);
335 // If we can't find a valid station set everything to zero
336 if (!_transmitter_valid && !mobile_valid ) {
337 _in_range_node->setBoolValue(false);
338 _distance_node->setDoubleValue(0);
339 _speed_node->setDoubleValue(0);
340 _time_node->setDoubleValue(0);
341 _bearing_node->setDoubleValue(0);
342 _transmitter_name = "";
343 _name_node->setStringValue(_transmitter_name.c_str());
346 } // end function update
349 TACAN::search (double frequency_mhz, double longitude_rad,
350 double latitude_rad, double altitude_m)
354 SG_LOG( SG_INSTR, SG_DEBUG, "tacan freq " << frequency_mhz );
357 _time_before_search_sec = 1.0;
359 //try any carriers first
360 FGNavRecord *carrier_tacan
361 = globals->get_carrierlist()->findStationByFreq( frequency_mhz );
362 _carrier_valid = (carrier_tacan != NULL);
364 if ( _carrier_valid ) {
365 SG_LOG( SG_INSTR, SG_DEBUG, "carrier transmitter valid " << _carrier_valid );
367 string str1( carrier_tacan->get_name() );
369 SGPropertyNode * branch = fgGetNode("ai/models", true);
370 vector<SGPropertyNode_ptr> carrier = branch->getChildren("carrier");
372 number = carrier.size();
374 SG_LOG( SG_INSTR, SG_DEBUG, "carrier " << number );
376 for ( i = 0; i < number; ++i ) {
377 string str2 ( carrier[i]->getStringValue("name", ""));
378 SG_LOG( SG_INSTR, SG_DEBUG, "carrier name " << str2 );
380 SG_LOG( SG_INSTR, SG_DEBUG, "strings 1 " << str1 << " 2 " << str2 );
381 unsigned int loc1= str1.find( str2, 0 );
382 if ( loc1 != string::npos && str2 != "" ) {
383 SG_LOG( SG_INSTR, SG_DEBUG, " string found" );
384 _carrier_lat = carrier[i]->getDoubleValue("position/latitude-deg");
385 _carrier_lon = carrier[i]->getDoubleValue("position/longitude-deg");
386 _carrier_elevation_ft = carrier_tacan->get_elev_ft();
387 _carrier_range_nm = carrier_tacan->get_range();
388 _carrier_bias = carrier_tacan->get_multiuse();
389 _carrier_name = carrier_tacan->get_name();
391 SG_LOG( SG_INSTR, SG_DEBUG, " carrier transmitter valid " << _carrier_valid );
395 SG_LOG( SG_INSTR, SG_DEBUG, " carrier transmitter invalid " << _carrier_valid );
399 SG_LOG( SG_INSTR, SG_DEBUG, "name " << _carrier_name);
400 SG_LOG( SG_INSTR, SG_DEBUG, "lat " << _carrier_lat << "lon " << _carrier_lon);
401 SG_LOG( SG_INSTR, SG_DEBUG, "elev " << _carrier_elevation_ft);
404 SG_LOG( SG_INSTR, SG_DEBUG, " carrier transmitter invalid " << _carrier_valid );
407 //try any tankers second
408 FGNavRecord *tanker_tacan
409 = globals->get_carrierlist()->findStationByFreq( frequency_mhz );
411 _tanker_valid = (tanker_tacan != NULL);
414 if ( _tanker_valid ) {
415 SG_LOG( SG_INSTR, SG_DEBUG, "tanker transmitter valid start " << _tanker_valid );
417 string str3( tanker_tacan->get_name() );
419 SGPropertyNode * branch = fgGetNode("ai/models", true);
420 vector<SGPropertyNode_ptr> tanker = branch->getChildren("aircraft");
422 number = tanker.size();
424 SG_LOG( SG_INSTR, SG_DEBUG, "tanker number " << number );
426 for ( i = 0; i < number; ++i ) {
427 string str4 ( tanker[i]->getStringValue("callsign", ""));
428 SG_LOG( SG_INSTR, SG_DEBUG, "tanker callsign " << str4 );
430 SG_LOG( SG_INSTR, SG_DEBUG, "strings 3 " << str3 << " 4 " << str4 );
431 unsigned int loc1= str3.find( str4, 0 );
432 if ( loc1 != string::npos && str4 != "" ) {
433 SG_LOG( SG_INSTR, SG_DEBUG, " string found" );
434 _tanker_lat = tanker[i]->getDoubleValue("position/latitude-deg");
435 _tanker_lon = tanker[i]->getDoubleValue("position/longitude-deg");
436 _tanker_elevation_ft = tanker[i]->getDoubleValue("position/altitude-ft");
437 _tanker_range_nm = tanker_tacan->get_range();
438 _tanker_bias = tanker_tacan->get_multiuse();
439 _tanker_name = tanker_tacan->get_name();
441 SG_LOG( SG_INSTR, SG_DEBUG, " tanker transmitter valid " << _tanker_valid );
445 SG_LOG( SG_INSTR, SG_DEBUG, " tanker transmitter invalid " << _tanker_valid );
449 SG_LOG( SG_INSTR, SG_DEBUG, "tanker name " << _tanker_name);
450 SG_LOG( SG_INSTR, SG_DEBUG, "lat " << _tanker_lat << "lon " << _tanker_lon);
451 SG_LOG( SG_INSTR, SG_DEBUG, "elev " << _tanker_elevation_ft);
452 SG_LOG( SG_INSTR, SG_DEBUG, "range " << _tanker_range_nm);
455 SG_LOG( SG_INSTR, SG_DEBUG, " tanker transmitter invalid " << _tanker_valid );
458 // try the TACAN/VORTAC list next
460 = globals->get_tacanlist()->findByFreq( frequency_mhz, longitude_rad,
461 latitude_rad, altitude_m);
463 _transmitter_valid = (tacan != NULL);
465 if ( _transmitter_valid ) {
466 SG_LOG( SG_INSTR, SG_DEBUG, "transmitter valid " << _transmitter_valid );
468 _transmitter_lat = tacan->get_lat();
469 _transmitter_lon = tacan->get_lon();
470 _transmitter_elevation_ft = tacan->get_elev_ft();
471 _transmitter_range_nm = tacan->get_range();
472 _transmitter_bias = tacan->get_multiuse();
473 _transmitter_name = tacan->get_name();
474 _name_node->setStringValue(_transmitter_name.c_str());
476 SG_LOG( SG_INSTR, SG_DEBUG, "name " << _transmitter_name);
477 SG_LOG( SG_INSTR, SG_DEBUG, "lat " << _transmitter_lat << "lon " << _transmitter_lon);
478 SG_LOG( SG_INSTR, SG_DEBUG, "elev " << _transmitter_elevation_ft);
481 SG_LOG( SG_INSTR, SG_DEBUG, "transmitter invalid " << _transmitter_valid );
486 TACAN::searchChannel (const string& _channel){
488 double frequency_khz = 0;
491 = globals->get_channellist()->findByChannel( _channel );
492 double _freq_valid = (freq != NULL);
493 SG_LOG( SG_INSTR, SG_DEBUG, "freq valid " << _freq_valid );
495 frequency_khz = freq->get_freq();
496 SG_LOG( SG_INSTR, SG_DEBUG, "freq output " << frequency_khz );
498 if (frequency_khz >=9620 && frequency_khz <= 12130)
499 return frequency_khz/100;
501 return frequency_khz = 0;
502 } // end TACAN::searchChannel