1 // adf.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 <simgear/math/sg_geodesy.hxx>
12 #include <simgear/math/sg_random.h>
13 #include <simgear/timing/sg_time.hxx>
15 #include <Main/fg_props.hxx>
16 #include <Main/util.hxx>
17 #include <Navaids/navlist.hxx>
26 // Use a bigger number to be more responsive, or a smaller number
27 // to be more sluggish.
28 #define RESPONSIVENESS 0.5
32 * Fiddle with the reception range a bit.
34 * TODO: better reception at night (??).
37 adjust_range (double transmitter_elevation_ft, double aircraft_altitude_ft,
40 double delta_elevation_ft =
41 aircraft_altitude_ft - transmitter_elevation_ft;
42 double range_nm = max_range_nm;
44 // kludge slightly better reception at
46 if (delta_elevation_ft < 0)
47 delta_elevation_ft = 200;
48 if (delta_elevation_ft <= 1000)
49 range_nm *= sqrt(delta_elevation_ft / 1000);
50 else if (delta_elevation_ft >= 5000)
51 range_nm *= sqrt(delta_elevation_ft / 5000);
52 if (range_nm >= max_range_nm * 3)
53 range_nm = max_range_nm * 3;
55 double rand = sg_random();
56 return range_nm + (range_nm * rand * rand);
60 ADF::ADF (SGPropertyNode *node )
62 _name(node->getStringValue("name", "adf")),
63 _num(node->getIntValue("number", 0)),
64 _time_before_search_sec(0),
65 _last_frequency_khz(-1),
66 _transmitter_valid(false),
67 _transmitter_pos(SGGeod::fromDeg(0, 0)),
68 _transmitter_cart(0, 0, 0),
69 _transmitter_range_nm(0),
85 branch = "/instrumentation/" + _name;
87 SGPropertyNode *node = fgGetNode(branch.c_str(), _num, true );
88 _longitude_node = fgGetNode("/position/longitude-deg", true);
89 _latitude_node = fgGetNode("/position/latitude-deg", true);
90 _altitude_node = fgGetNode("/position/altitude-ft", true);
91 _heading_node = fgGetNode("/orientation/heading-deg", true);
92 _serviceable_node = node->getChild("serviceable", 0, true);
93 _error_node = node->getChild("error-deg", 0, true);
94 _electrical_node = fgGetNode("/systems/electrical/outputs/adf", true);
95 branch = branch + "/frequencies";
96 SGPropertyNode *fnode = node->getChild("frequencies", 0, true);
97 _frequency_node = fnode->getChild("selected-khz", 0, true);
98 _mode_node = node->getChild("mode", 0, true);
99 _volume_node = node->getChild("volume-norm", 0, true);
100 _in_range_node = node->getChild("in-range", 0, true);
101 _bearing_node = node->getChild("indicated-bearing-deg", 0, true);
102 _ident_node = node->getChild("ident", 0, true);
103 _ident_audible_node = node->getChild("ident-audible", 0, true);
104 _power_btn_node = node->getChild("power-btn", 0, true);
106 if (_power_btn_node->getType() == simgear::props::NONE)
107 _power_btn_node->setBoolValue(true); // front end didn't implement a power button
109 SGSoundMgr *smgr = globals->get_soundmgr();
110 _sgr = smgr->find("avionics", true);
111 _sgr->tie_to_listener();
115 std::ostringstream temp;
116 temp << _name << _num;
117 _adf_ident = temp.str();
121 ADF::update (double delta_time_sec)
123 // If it's off, don't waste any time.
124 if (_electrical_node->getDoubleValue() < 8.0
125 || !_serviceable_node->getBoolValue()
126 || !_power_btn_node->getBoolValue() ) {
127 _ident_node->setStringValue("");
131 string mode = _mode_node->getStringValue();
132 if (mode == "ant" || mode == "test") set_bearing(delta_time_sec, 90);
133 if (mode != "bfo" && mode != "adf") {
134 _ident_node->setStringValue("");
138 int frequency_khz = _frequency_node->getIntValue();
139 if (frequency_khz != _last_frequency_khz) {
140 _time_before_search_sec = 0;
141 _last_frequency_khz = frequency_khz;
144 // Get the aircraft position
145 double longitude_deg = _longitude_node->getDoubleValue();
146 double latitude_deg = _latitude_node->getDoubleValue();
147 double altitude_m = _altitude_node->getDoubleValue();
149 double longitude_rad = longitude_deg * SGD_DEGREES_TO_RADIANS;
150 double latitude_rad = latitude_deg * SGD_DEGREES_TO_RADIANS;
152 // On timeout, scan again
153 _time_before_search_sec -= delta_time_sec;
154 if (_time_before_search_sec < 0)
155 search(frequency_khz, longitude_rad, latitude_rad, altitude_m);
157 if (!_transmitter_valid) {
158 _ident_node->setStringValue("");
162 // Calculate the bearing to the transmitter
163 SGGeod geod = SGGeod::fromRadM(longitude_rad, latitude_rad, altitude_m);
164 SGVec3d location = SGVec3d::fromGeod(geod);
166 double distance_nm = dist(_transmitter_cart, location) * SG_METER_TO_NM;
167 double range_nm = adjust_range(_transmitter_pos.getElevationFt(),
168 altitude_m * SG_METER_TO_FEET,
169 _transmitter_range_nm);
171 if (distance_nm <= range_nm) {
173 double bearing, az2, s;
174 double heading = _heading_node->getDoubleValue();
176 geo_inverse_wgs_84(geod, _transmitter_pos,
178 _in_range_node->setBoolValue(true);
183 set_bearing(delta_time_sec, bearing);
187 if ( _ident_audible_node->getBoolValue() )
188 volume = _volume_node->getFloatValue();
192 if ( volume != _last_volume ) {
193 _last_volume = volume;
195 SGSoundSample *sound;
196 sound = _sgr->find( _adf_ident );
198 sound->set_volume( volume );
200 SG_LOG( SG_GENERAL, SG_ALERT, "Can't find adf-ident sound" );
203 time_t cur_time = globals->get_time_params()->get_cur_time();
204 if ( _last_ident_time < cur_time - 30 ) {
205 _last_ident_time = cur_time;
209 if ( _ident_count < 4 ) {
210 if ( !_sgr->is_playing(_adf_ident) && (volume > 0.05) ) {
211 _sgr->play_once( _adf_ident );
216 _in_range_node->setBoolValue(false);
217 _ident_node->setStringValue("");
218 _sgr->stop( _adf_ident );
223 ADF::search (double frequency_khz, double longitude_rad,
224 double latitude_rad, double altitude_m)
228 _time_before_search_sec = 1.0;
230 // try the ILS list first
231 FGNavRecord *nav = globals->get_navlist()->findByFreq(frequency_khz,
232 SGGeod::fromRadM(longitude_rad, latitude_rad, altitude_m));
234 _transmitter_valid = (nav != NULL);
235 if ( _transmitter_valid ) {
236 ident = nav->get_trans_ident();
237 if ( ident != _last_ident ) {
238 _transmitter_pos = nav->geod();
239 _transmitter_cart = nav->cart();
240 _transmitter_range_nm = nav->get_range();
244 if ( _last_ident != ident ) {
246 _ident_node->setStringValue(ident.c_str());
248 if ( _sgr->exists( _adf_ident ) ) {
249 // stop is required! -- remove alone wouldn't stop immediately
250 _sgr->stop( _adf_ident );
251 _sgr->remove( _adf_ident );
254 SGSoundSample *sound;
255 sound = morse.make_ident( ident, LO_FREQUENCY );
256 sound->set_volume(_last_volume = 0);
257 _sgr->add( sound, _adf_ident );
259 int offset = (int)(sg_random() * 30.0);
260 _ident_count = offset / 4;
261 _last_ident_time = globals->get_time_params()->get_cur_time() -
267 ADF::set_bearing (double dt, double bearing_deg)
269 double old_bearing_deg = _bearing_node->getDoubleValue();
271 while ((bearing_deg - old_bearing_deg) >= 180)
272 old_bearing_deg += 360;
273 while ((bearing_deg - old_bearing_deg) <= -180)
274 old_bearing_deg -= 360;
275 bearing_deg += _error_node->getDoubleValue();
277 fgGetLowPass(old_bearing_deg, bearing_deg, dt * RESPONSIVENESS);
279 _bearing_node->setDoubleValue(bearing_deg);