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flightgear/src/Navaids/ilslist.cxx

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// ilslist.cxx -- ils management class
//
// Written by Curtis Olson, started April 2000.
//
// Copyright (C) 2000 Curtis L. Olson - curt@flightgear.org
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of the
// License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
//
// $Id$
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <simgear/debug/logstream.hxx>
#include <simgear/misc/sgstream.hxx>
#include <simgear/math/sg_geodesy.hxx>
#include "mkrbeacons.hxx"
#include "ilslist.hxx"
FGILSList *current_ilslist;
// Constructor
FGILSList::FGILSList( void ) {
}
// Destructor
FGILSList::~FGILSList( void ) {
}
// load the navaids and build the map
bool FGILSList::init( SGPath path ) {
ilslist.erase( ilslist.begin(), ilslist.end() );
sg_gzifstream in( path.str() );
if ( !in.is_open() ) {
SG_LOG( SG_GENERAL, SG_ALERT, "Cannot open file: " << path.str() );
exit(-1);
}
// read in each line of the file
in >> skipeol;
in >> skipcomment;
// double min = 1000000.0;
// double max = 0.0;
#ifdef __MWERKS__
char c = 0;
while ( in.get(c) && c != '\0' ) {
in.putback(c);
#else
while ( ! in.eof() ) {
#endif
FGILS *ils = new FGILS;
in >> (*ils);
if ( ils->get_ilstype() == '[' ) {
break;
}
/* cout << "typename = " << ils.get_ilstypename() << endl;
cout << " aptcode = " << ils.get_aptcode() << endl;
cout << " twyno = " << ils.get_rwyno() << endl;
cout << " locfreq = " << ils.get_locfreq() << endl;
cout << " locident = " << ils.get_locident() << endl << endl; */
ilslist[ils->get_locfreq()].push_back(ils);
in >> skipcomment;
/* if ( ils.get_locfreq() < min ) {
min = ils.get_locfreq();
}
if ( ils.get_locfreq() > max ) {
max = ils.get_locfreq();
} */
// update the marker beacon list
if ( fabs(ils->get_omlon()) > SG_EPSILON ||
fabs(ils->get_omlat()) > SG_EPSILON ) {
current_beacons->add( ils->get_omlon(), ils->get_omlat(),
ils->get_gselev(), FGMkrBeacon::OUTER );
}
if ( fabs(ils->get_mmlon()) > SG_EPSILON ||
fabs(ils->get_mmlat()) > SG_EPSILON ) {
current_beacons->add( ils->get_mmlon(), ils->get_mmlat(),
ils->get_gselev(), FGMkrBeacon::MIDDLE );
}
if ( fabs(ils->get_imlon()) > SG_EPSILON ||
fabs(ils->get_imlat()) > SG_EPSILON ) {
current_beacons->add( ils->get_imlon(), ils->get_imlat(),
ils->get_gselev(), FGMkrBeacon::INNER );
}
}
// cout << "min freq = " << min << endl;
// cout << "max freq = " << max << endl;
return true;
}
// Query the database for the specified frequency. It is assumed that
// there will be multiple stations with matching frequencies so a
// position must be specified. Lon and lat are in degrees, elev is in
// meters.
FGILS *FGILSList::findByFreq( double freq,
double lon, double lat, double elev )
{
FGILS *ils = NULL;
ils_list_type stations = ilslist[(int)(freq*100.0 + 0.5)];
double best_angle = 362.0;
// double az1, az2, s;
Point3D aircraft = sgGeodToCart( Point3D(lon, lat, elev) );
Point3D station;
double d2;
for ( unsigned int i = 1; i < stations.size(); ++i ) {
// cout << " testing " << current->get_locident() << endl;
station = Point3D(stations[i]->get_x(),
stations[i]->get_y(),
stations[i]->get_z());
// cout << " aircraft = " << aircraft << " station = " << station
// << endl;
d2 = aircraft.distance3Dsquared( station );
// cout << " distance = " << d << " ("
// << FG_ILS_DEFAULT_RANGE * SG_NM_TO_METER
// * FG_ILS_DEFAULT_RANGE * SG_NM_TO_METER
// << ")" << endl;
// cout << " dist = " << s << endl;
// match up to twice the published range so we can model
// reduced signal strength. The assumption is that there will
// be maximum of two possbile stations of a particular
// frequency in range. If two exist, one will be associated
// with each end of the runway. In this case, pick the
// station pointing most directly at us.
if ( d2 < (2* FG_ILS_DEFAULT_RANGE * SG_NM_TO_METER
* 2 * FG_ILS_DEFAULT_RANGE * SG_NM_TO_METER) ) {
// Get our bearing from this station.
double reciprocal_bearing, dummy;
double a_lat_deg = lat * SGD_RADIANS_TO_DEGREES;
double a_lon_deg = lon * SGD_RADIANS_TO_DEGREES;
// Locator beam direction
double s_ils_deg = stations[i]->get_locheading() - 180.0;
if ( s_ils_deg < 0.0 ) { s_ils_deg += 360.0; }
double angle_to_beam_deg;
// printf("**ALI geting geo_inverse_wgs_84 with elev = %.2f, a.lat = %.2f, a.lon = %.2f,
// s.lat = %.2f, s.lon = %.2f\n", elev,a_lat_deg,a_lon_deg,stations[i]->get_loclat(),stations[i]->get_loclon());
geo_inverse_wgs_84( elev, stations[i]->get_loclat(),
stations[i]->get_loclon(), a_lat_deg, a_lon_deg,
&reciprocal_bearing, &dummy, &dummy );
angle_to_beam_deg = fabs(reciprocal_bearing - s_ils_deg);
if ( angle_to_beam_deg <= best_angle ) {
ils = stations[i];
best_angle = angle_to_beam_deg;
}
}
}
return ils;
}