1 // navrecord.cxx -- generic vor/dme/ndb class
3 // Written by Curtis Olson, started May 2004.
5 // Copyright (C) 2004 Curtis L. Olson - http://www.flightgear.org/~curt
7 // This program is free software; you can redistribute it and/or
8 // modify it under the terms of the GNU General Public License as
9 // published by the Free Software Foundation; either version 2 of the
10 // License, or (at your option) any later version.
12 // This program is distributed in the hope that it will be useful, but
13 // WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 // General Public License for more details.
17 // You should have received a copy of the GNU General Public License
18 // along with this program; if not, write to the Free Software
19 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
29 #include <simgear/misc/sgstream.hxx>
30 #include <simgear/misc/sg_path.hxx>
31 #include <simgear/structure/exception.hxx>
32 #include <simgear/debug/logstream.hxx>
33 #include <simgear/sg_inlines.h>
34 #include <simgear/props/props.hxx>
35 #include <simgear/props/props_io.hxx>
37 #include <Navaids/navrecord.hxx>
38 #include <Navaids/navdb.hxx>
39 #include <Airports/runways.hxx>
40 #include <Airports/simple.hxx>
41 #include <Airports/xmlloader.hxx>
43 #include <Main/fg_props.hxx>
45 FGNavRecord::FGNavRecord(Type aTy, const std::string& aIdent,
46 const std::string& aName, const SGGeod& aPos,
47 int aFreq, int aRange, double aMultiuse) :
48 FGPositioned(aTy, aIdent, aPos),
57 initAirportRelation();
59 // Ranges are included with the latest data format, no need to
60 // assign our own defaults, unless the range is not set for some
63 SG_LOG(SG_GENERAL, SG_WARN, "navaid " << ident() << " has no range set, using defaults");
67 range = FG_NAV_DEFAULT_RANGE;
73 range = FG_LOC_DEFAULT_RANGE;
77 range = FG_DME_DEFAULT_RANGE;
81 range = FG_LOC_DEFAULT_RANGE;
85 init(true); // init FGPositioned (now position is adjusted)
88 void FGNavRecord::initAirportRelation()
90 if ((type() < ILS) || (type() > GS)) {
91 return; // not airport-located
94 mRunway = getRunwayFromName(_name);
100 readAirportSceneryData();
103 // fudge elevation to the runway elevation if it's not specified
104 if (fabs(elevation()) < 0.01) {
105 mPosition.setElevationFt(mRunway->elevation());
108 if (type() == ILS || type() == LOC) {
109 mRunway->setILS(this);
112 // align localizers with their runway
113 if ((type() == ILS) || (type() == LOC)) {
114 if (!fgGetBool("/sim/navdb/localizers/auto-align", true)) {
119 = fgGetDouble( "/sim/navdb/localizers/auto-align-threshold-deg", 5.0 );
120 alignLocaliserWithRunway(threshold);
124 void FGNavRecord::readAirportSceneryData()
126 // allow users to disable the scenery data in the short-term
127 // longer term, this option can probably disappear
128 if (!fgGetBool("/sim/use-scenery-airport-data")) {
133 SGPropertyNode_ptr rootNode = new SGPropertyNode;
134 if (!XMLLoader::findAirportData(mRunway->airport()->ident(), "ils", path)) {
138 readProperties(path.str(), rootNode);
139 SGPropertyNode* runwayNode, *ilsNode;
140 for (int i=0; (runwayNode = rootNode->getChild("runway", i)) != NULL; ++i) {
141 for (int j=0; (ilsNode = runwayNode->getChild("ils", j)) != NULL; ++j) {
142 // must match on both nav-ident and runway ident, to support the following:
143 // - runways with multiple distinct ILS installations (KEWD, for example)
144 // - runways where both ends share the same nav ident (LFAT, for example)
145 if ((ilsNode->getStringValue("nav-id") == ident()) &&
146 (ilsNode->getStringValue("rwy") == mRunway->ident())) {
147 processSceneryILS(ilsNode);
150 } // of ILS iteration
151 } // of runway iteration
154 void FGNavRecord::processSceneryILS(SGPropertyNode* aILSNode)
156 double hdgDeg = aILSNode->getDoubleValue("hdg-deg"),
157 lon = aILSNode->getDoubleValue("lon"),
158 lat = aILSNode->getDoubleValue("lat"),
159 elevM = aILSNode->getDoubleValue("elev-m");
161 mPosition = SGGeod::fromDegM(lon, lat, elevM);
165 void FGNavRecord::alignLocaliserWithRunway(double aThreshold)
167 // find the distance from the threshold to the localizer
168 double dist = SGGeodesy::distanceM(mPosition, mRunway->threshold());
170 // back project that distance along the runway center line
171 SGGeod newPos = mRunway->pointOnCenterline(dist);
173 double hdg_diff = get_multiuse() - mRunway->headingDeg();
174 SG_NORMALIZE_RANGE(hdg_diff, -180.0, 180.0);
176 if ( fabs(hdg_diff) <= aThreshold ) {
177 mPosition = SGGeod::fromGeodFt(newPos, mPosition.getElevationFt());
178 set_multiuse( mRunway->headingDeg() );
180 SG_LOG(SG_GENERAL, SG_DEBUG, "localizer:" << ident() << ", aligning with runway "
181 << mRunway->ident() << " exceeded heading threshold");
185 double FGNavRecord::localizerWidth() const
191 SGVec3d thresholdCart(SGVec3d::fromGeod(mRunway->threshold()));
192 double axisLength = dist(cart(), thresholdCart);
193 double landingLength = dist(thresholdCart, SGVec3d::fromGeod(mRunway->end()));
195 // Reference: http://dcaa.slv.dk:8000/icaodocs/
196 // ICAO standard width at threshold is 210 m = 689 feet = approx 700 feet.
197 // ICAO 3.1.1 half course = DDM = 0.0775
198 // ICAO 3.1.3.7.1 Sensitivity 0.00145 DDM/m at threshold
199 // implies peg-to-peg of 214 m ... we will stick with 210.
200 // ICAO 3.1.3.7.1 "Course sector angle shall not exceed 6 degrees."
202 // Very short runway: less than 1200 m (4000 ft) landing length:
203 if (landingLength < 1200.0) {
204 // ICAO fudges localizer sensitivity for very short runways.
205 // This produces a non-monotonic sensitivity-versus length relation.
206 axisLength += 1050.0;
209 // Example: very short: San Diego KMYF (Montgomery Field) ILS RWY 28R
210 // Example: short: Tom's River KMJX (Robert J. Miller) ILS RWY 6
211 // Example: very long: Denver KDEN (Denver) ILS RWY 16R
212 double raw_width = 210.0 / axisLength * SGD_RADIANS_TO_DEGREES;
213 return raw_width < 6.0? raw_width : 6.0;
217 FGTACANRecord::FGTACANRecord(void) :
225 operator >> ( std::istream& in, FGTACANRecord& n )
227 in >> n.channel >> n.freq ;
228 //getline( in, n.name );