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Ed Sirett submitted a patch to consider antenna orientation when searching

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for localizers.  I further hacked this to support GS and DME transmitters
(although Robin's DME transmitter data doesn't convey orientation
unfortunately.)
This commit is contained in:
curt 2004-07-19 18:02:00 +00:00
parent 485c66ed3e
commit d5a5c9bb0e
1 changed files with 52 additions and 5 deletions
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57
src/Navaids/navlist.cxx
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@ -182,8 +182,9 @@ FGNavRecord *FGNavList::findNavFromList( const Point3D &aircraft,
{
FGNavRecord *nav = NULL;
Point3D station;
double dist;
double min_dist = FG_NAV_MAX_RANGE * SG_NM_TO_METER;
double d2; // in meters squared
double min_dist
= FG_NAV_MAX_RANGE*SG_NM_TO_METER*FG_NAV_MAX_RANGE*SG_NM_TO_METER;
// find the closest station within a sensible range (FG_NAV_MAX_RANGE)
for ( unsigned int i = 0; i < stations.size(); ++i ) {
@ -192,14 +193,60 @@ FGNavRecord *FGNavList::findNavFromList( const Point3D &aircraft,
stations[i]->get_y(),
stations[i]->get_z() );
dist = aircraft.distance3D( station );
d2 = aircraft.distance3Dsquared( station );
// cout << " dist = " << sqrt(d)
// << " range = " << current->get_range() * SG_NM_TO_METER
// << endl;
if ( dist < min_dist ) {
min_dist = dist;
// LOC, ILS, GS, and DME antenna's could potentially be
// installed at the opposite end of the runway. So it's not
// enough to simply find the closest antenna with the right
// frequency. We need the closest antenna with the right
// frequency that is most oriented towards us. (We penalize
// stations that are facing away from us by adding 5000 meters
// which is further than matching stations would ever be
// placed from each other. (Do the expensive check only for
// directional atennas and only when there is a chance it is
// the closest station.)
if ( d2 < min_dist &&
(stations[i]->get_type() == 4 || stations[i]->get_type() == 5 ||
stations[i]->get_type() == 6 || stations[i]->get_type() == 12) )
{
double hdg_deg = 0.0;
if ( stations[i]->get_type() == 4 || stations[i]->get_type() == 5 ){
hdg_deg = stations[i]->get_multiuse();
} else if ( stations[i]->get_type() == 6 ) {
int tmp = (int)(stations[i]->get_multiuse() / 1000.0);
hdg_deg = stations[i]->get_multiuse() - (tmp * 1000);
} else if ( stations[i]->get_type() == 12 ) {
// oops, Robin's data format doesn't give us the
// needed information to compute a heading for a DME
// transmitter. FIXME Robin!
}
double az1 = 0.0, az2 = 0.0, s = 0.0;
double elev_m = 0.0, lat_rad = 0.0, lon_rad = 0.0;
double xyz[3] = { aircraft.x(), aircraft.y(), aircraft.z() };
sgCartToGeod( xyz, &lat_rad, &lon_rad, &elev_m );
geo_inverse_wgs_84( elev_m,
lat_rad * SG_RADIANS_TO_DEGREES,
lon_rad * SG_RADIANS_TO_DEGREES,
stations[i]->get_lat(), stations[i]->get_lon(),
&az1, &az2, &s);
az1 = az1 - stations[i]->get_multiuse();
if ( az1 > 180.0) az1 -= 360.0;
if ( az1 < -180.0) az1 += 360.0;
// penalize opposite facing stations by adding 5000 meters
// (squared) which is further than matching stations would
// ever be placed from each other.
if ( fabs(az1) > 90.0 ) {
d2 += 5000*5000;
}
}
if ( d2 < min_dist ) {
min_dist = d2;
nav = stations[i];
}
}