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.
6 #include <simgear/compiler.h>
7 #include <simgear/math/sg_geodesy.hxx>
8 #include <simgear/math/sg_random.h>
10 #include <Main/fg_props.hxx>
11 #include <Navaids/navlist.hxx>
22 * Start by calculating the radar horizon based on the elevation
23 * difference, then clamp to the maximum, then add a fudge for
24 * borderline reception.
27 adjust_range (double transmitter_elevation_ft, double aircraft_altitude_ft,
31 double delta_elevation_ft =
32 fabs(aircraft_altitude_ft - transmitter_elevation_ft);
33 double range_nm = 1.23 * sqrt(delta_elevation_ft);
34 if (range_nm > max_range_nm)
35 range_nm = max_range_nm;
36 else if (range_nm < 20.0)
38 double rand = sg_random();
39 SG_LOG( SG_INSTR, SG_DEBUG, " tacan range " << range_nm << " max range " << max_range_nm);
40 return range_nm + (range_nm * rand * rand);
44 TACAN::TACAN ( SGPropertyNode *node )
45 : _last_distance_nm(0),
46 _last_frequency_mhz(-1),
47 _time_before_search_sec(0),
48 _carrier_valid(false),
49 _transmitter_valid(false),
50 _transmitter_elevation_ft(0),
51 _transmitter_range_nm(0),
52 _transmitter_bias(0.0),
59 for ( i = 0; i < node->nChildren(); ++i ) {
60 SGPropertyNode *child = node->getChild(i);
61 string cname = child->getName();
62 string cval = child->getStringValue();
63 if ( cname == "name" ) {
65 } else if ( cname == "number" ) {
66 num = child->getIntValue();
68 SG_LOG( SG_INSTR, SG_DEBUG, "Error in TACAN config logic" );
69 if ( name.length() ) {
70 SG_LOG( SG_INSTR, SG_DEBUG, "Section = " << name );
77 : _last_distance_nm(0),
78 _last_frequency_mhz(-1),
79 _time_before_search_sec(0),
80 _carrier_valid(false),
81 _transmitter_valid(false),
82 _transmitter_elevation_ft(0),
83 _transmitter_range_nm(0),
84 _transmitter_bearing_deg(0),
85 _transmitter_bias(0.0),
86 _transmitter_name(""),
99 branch = "/instrumentation/" + name;
101 SGPropertyNode *node = fgGetNode(branch.c_str(), num, true );
103 _longitude_node = fgGetNode("/position/longitude-deg", true);
104 _latitude_node = fgGetNode("/position/latitude-deg", true);
105 _altitude_node = fgGetNode("/position/altitude-ft", true);
106 _serviceable_node = node->getChild("serviceable", 0, true);
107 _electrical_node = fgGetNode("/systems/electrical/outputs/tacan", true);
108 SGPropertyNode *fnode = node->getChild("frequencies", 0, true);
109 _source_node = fnode->getChild("source", 0, true);
110 _frequency_node = fnode->getChild("selected-mhz", 0, true);
111 _channel_node = fnode->getChild("selected-channel", 1, true);
112 _channel_node = fnode->getChild("selected-channel", 2, true);
113 _channel_node = fnode->getChild("selected-channel", 3, true);
114 _channel_node = fnode->getChild("selected-channel", 4, true);
115 _in_range_node = node->getChild("in-range", 0, true);
116 _distance_node = node->getChild("indicated-distance-nm", 0, true);
117 _speed_node = node->getChild("indicated-ground-speed-kt", 0, true);
118 _time_node = node->getChild("indicated-time-min", 0, true);
119 _name_node = node->getChild("name", 0, true);
120 _bearing_node = node->getChild("indicated-bearing-true-deg", 0, true);
121 _carrier_lat_node = fgGetNode("/ai/models/carrier/position/latitude-deg", true);
122 _carrier_lon_node = fgGetNode("/ai/models/carrier/position/longitude-deg", true);
123 // _carrier_name_node = fgGetNode("/ai/models/carrier/name", true);
125 SGPropertyNode *cnode = fgGetNode("/ai/models/carrier", num, true );
126 _carrier_name_node = cnode->getChild("name", 0, true);
130 TACAN::update (double delta_time_sec)
135 double carrier_az2= 0;
136 double carrier_bearing = 0;
137 double carrier_distance = 0;
138 double frequency_mhz = 0;
139 string _channel, _last_channel, _channel_1, _channel_2,_channel_3, _channel_4;
141 // If it's off, don't waste any time.
142 if (!_serviceable_node->getBoolValue() ||
143 !_electrical_node->getBoolValue()
145 _last_distance_nm = 0;
146 _in_range_node->setBoolValue(false);
147 _distance_node->setDoubleValue(0);
148 _speed_node->setDoubleValue(0);
149 _time_node->setDoubleValue(0);
150 SG_LOG( SG_INSTR, SG_DEBUG, "skip tacan " );
153 //SG_LOG( SG_INSTR, SG_DEBUG, "run tacan " );
156 // Figure out the source
157 const char * source = _source_node->getStringValue();
159 if (source[0] == '\0') {
161 branch = "/instrumentation/" + name + "/frequencies/selected-channel";
162 // branch = "/instrumentation/" + _name + "/frequencies/selected-mhz";
163 _source_node->setStringValue(branch.c_str());
164 source = _source_node->getStringValue();
165 SG_LOG( SG_INSTR, SG_DEBUG, "source " << source );
168 _channel_1 = fgGetString("/instrumentation/tacan/frequencies/selected-channel[1]");
169 _channel_2 = fgGetString("/instrumentation/tacan/frequencies/selected-channel[2]");
170 _channel_3 = fgGetString("/instrumentation/tacan/frequencies/selected-channel[3]");
171 _channel_4 = fgGetString("/instrumentation/tacan/frequencies/selected-channel[4]");
172 SG_LOG( SG_INSTR, SG_DEBUG, "channels " << _channel_1 << _channel_2 << _channel_3 << _channel_4);
173 _channel = _channel_1 + _channel_2 + _channel_3 + _channel_4;
174 SG_LOG( SG_INSTR, SG_DEBUG, "channel " << _channel );
176 // Get the frequecncy
177 if (_channel != _last_channel) {
178 _time_before_search_sec = 0;
179 _last_channel = _channel;
180 frequency_mhz = searchChannel(_channel);
181 SG_LOG( SG_INSTR, SG_DEBUG, "frequency " << frequency_mhz );
182 _frequency_node->setDoubleValue(frequency_mhz);
185 // Get the aircraft position
186 double longitude_deg = _longitude_node->getDoubleValue();
187 double latitude_deg = _latitude_node->getDoubleValue();
188 double altitude_m = _altitude_node->getDoubleValue() * SG_FEET_TO_METER;
189 double longitude_rad = longitude_deg * SGD_DEGREES_TO_RADIANS;
190 double latitude_rad = latitude_deg * SGD_DEGREES_TO_RADIANS;
192 // On timeout, scan again
193 _time_before_search_sec -= delta_time_sec;
194 if (_time_before_search_sec < 0 && frequency_mhz > 0)
195 search(frequency_mhz, longitude_rad,
196 latitude_rad, altitude_m);
198 // Calculate the distance to the transmitter
200 //calculate the bearing and range of the carrier from the aircraft
201 SG_LOG( SG_INSTR, SG_DEBUG, "carrier_lat " << _carrier_lat);
202 SG_LOG( SG_INSTR, SG_DEBUG, "carrier_lon " << _carrier_lon);
203 SG_LOG( SG_INSTR, SG_DEBUG, "carrier_name " << _carrier_name);
204 SG_LOG( SG_INSTR, SG_DEBUG, "carrier_valid " << _carrier_valid);
205 geo_inverse_wgs_84(altitude_m,
210 &carrier_bearing, &carrier_az2, &carrier_distance);
213 //calculate the bearing and range of the station from the aircraft
214 geo_inverse_wgs_84(altitude_m,
219 &bearing, &az2, &distance);
223 if ( carrier_distance <= distance && _carrier_valid) {
224 SG_LOG( SG_INSTR, SG_DEBUG, "carrier_distance_nm " << carrier_distance);
225 SG_LOG( SG_INSTR, SG_DEBUG, "distance_nm " << distance);
226 bearing = carrier_bearing;
227 distance = carrier_distance;
228 _transmitter_elevation_ft = _carrier_elevation_ft;
229 _transmitter_range_nm = _carrier_range_nm;
230 _transmitter_bias = _carrier_bias;
231 _transmitter_name = _carrier_name;
232 _name_node->setStringValue(_transmitter_name.c_str());
235 double distance_nm = distance * SG_METER_TO_NM;
236 SG_LOG( SG_INSTR, SG_DEBUG, "distance_nm " << distance_nm << " bearing " << bearing);
239 sgGeodToCart(Point3D(longitude_rad, latitude_rad, altitude_m));
240 double distance_nm = _transmitter.distance3D(location) * SG_METER_TO_NM;*/
242 double range_nm = adjust_range(_transmitter_elevation_ft,
243 altitude_m * SG_METER_TO_FEET,
244 _transmitter_range_nm);
246 if (distance_nm <= range_nm) {
247 double speed_kt = (fabs(distance_nm - _last_distance_nm) *
248 ((1 / delta_time_sec) * 3600.0));
249 _last_distance_nm = distance_nm;
251 _in_range_node->setBoolValue(true);
252 double tmp_dist = distance_nm - _transmitter_bias;
253 if ( tmp_dist < 0.0 ) {
256 _distance_node->setDoubleValue( tmp_dist );
257 _speed_node->setDoubleValue(speed_kt);
258 _time_node->setDoubleValue(distance_nm/speed_kt*60.0);
259 _bearing_node->setDoubleValue(bearing);
262 _last_distance_nm = 0;
263 _in_range_node->setBoolValue(false);
264 _distance_node->setDoubleValue(0);
265 _speed_node->setDoubleValue(0);
266 _time_node->setDoubleValue(0);
267 _bearing_node->setDoubleValue(0);
270 // If we can't find a valid station set everything to zero
271 if (!_transmitter_valid && !_carrier_valid)
273 _in_range_node->setBoolValue(false);
274 _distance_node->setDoubleValue(0);
275 _speed_node->setDoubleValue(0);
276 _time_node->setDoubleValue(0);
277 _bearing_node->setDoubleValue(0);
278 _transmitter_name = "";
279 _name_node->setStringValue(_transmitter_name.c_str());
282 } // end function update
285 TACAN::search (double frequency_mhz, double longitude_rad,
286 double latitude_rad, double altitude_m)
289 SG_LOG( SG_INSTR, SG_DEBUG, "tacan freq " << frequency_mhz );
292 _time_before_search_sec = 1.0;
294 //try any carriers first
295 FGNavRecord *carrier_tacan
296 = globals->get_carrierlist()->findStationByFreq( frequency_mhz );
297 _carrier_valid = (carrier_tacan != NULL);
299 if ( _carrier_valid ) {
300 SG_LOG( SG_INSTR, SG_DEBUG, "carrier transmitter valid " << _carrier_valid );
302 string str1( carrier_tacan->get_name() );
304 SGPropertyNode * branch = fgGetNode("ai/models", true);
305 vector<SGPropertyNode_ptr> carrier = branch->getChildren("carrier");
307 int number = carrier.size();
309 SG_LOG( SG_INSTR, SG_DEBUG, "carrier " << number );
312 for ( i = 0; i < number; ++i ) {
313 string str2 ( carrier[i]->getStringValue("name", ""));
314 // SG_LOG( SG_INSTR, SG_DEBUG, "carrier name " << str2 );
317 //string str2 ( _carrier_name_node->getStringValue());
318 SG_LOG( SG_INSTR, SG_DEBUG, "strings 1 " << str1 << " 2 " << str2 );
319 unsigned int loc1= str1.find( str2, 0 );
320 if( loc1 != string::npos && str2 != "" ){
321 SG_LOG( SG_INSTR, SG_DEBUG, " string found" );
322 _carrier_lat = _carrier_lat_node->getDoubleValue();
323 _carrier_lon = _carrier_lon_node->getDoubleValue();
324 _carrier_elevation_ft = carrier_tacan->get_elev_ft();
325 _carrier_range_nm = carrier_tacan->get_range();
326 _carrier_bias = carrier_tacan->get_multiuse();
327 _carrier_name = carrier_tacan->get_name();
329 SG_LOG( SG_INSTR, SG_DEBUG, " carrier transmitter valid " << _carrier_valid );
334 SG_LOG( SG_INSTR, SG_DEBUG, " carrier transmitter invalid " << _carrier_valid );
338 //_name_node->setStringValue(_transmitter_name.c_str());
340 SG_LOG( SG_INSTR, SG_DEBUG, "name " << _carrier_name);
341 SG_LOG( SG_INSTR, SG_DEBUG, "lat " << _carrier_lat << "lon " << _carrier_lon);
342 SG_LOG( SG_INSTR, SG_DEBUG, "elev " << _carrier_elevation_ft);
345 SG_LOG( SG_INSTR, SG_DEBUG, " carrier transmitter invalid " << _carrier_valid );
349 // try the TACAN/VORTAC list next
351 = globals->get_tacanlist()->findByFreq( frequency_mhz, longitude_rad,
352 latitude_rad, altitude_m);
354 _transmitter_valid = (tacan != NULL);
356 if ( _transmitter_valid ) {
357 SG_LOG( SG_INSTR, SG_DEBUG, "transmitter valid " << _transmitter_valid );
359 _transmitter_lat = tacan->get_lat();
360 _transmitter_lon = tacan->get_lon();
361 _transmitter_elevation_ft = tacan->get_elev_ft();
362 _transmitter_range_nm = tacan->get_range();
363 _transmitter_bias = tacan->get_multiuse();
364 _transmitter_name = tacan->get_name();
365 _name_node->setStringValue(_transmitter_name.c_str());
367 SG_LOG( SG_INSTR, SG_DEBUG, "name " << _transmitter_name);
368 SG_LOG( SG_INSTR, SG_DEBUG, "lat " << _transmitter_lat << "lon " << _transmitter_lon);
369 SG_LOG( SG_INSTR, SG_DEBUG, "elev " << _transmitter_elevation_ft);
372 SG_LOG( SG_INSTR, SG_DEBUG, "transmitter invalid " << _transmitter_valid );
378 TACAN::searchChannel (const string& _channel){
380 double frequency_khz = 0;
383 = globals->get_channellist()->findByChannel( _channel );
384 double _freq_valid = (freq != NULL);
385 SG_LOG( SG_INSTR, SG_DEBUG, "freq valid " << _freq_valid );
387 frequency_khz = freq->get_freq();
388 SG_LOG( SG_INSTR, SG_DEBUG, "freq output " << frequency_khz );
390 if (frequency_khz >9620 && frequency_khz <= 12130)return frequency_khz/100;
392 return frequency_khz = 0;
393 } // end TACAN::searchChannel