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Better estimate of cross track heading error. Also, make sure it is

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computed correctly when flying outbound from a vor.
This commit is contained in:
curt 2005-12-29 04:07:49 +00:00
parent 1ae9849062
commit c3f1331e52
1 changed files with 28 additions and 21 deletions
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49
src/Instrumentation/navradio.cxx
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@ -415,6 +415,23 @@ FGNavRadio::update(double dt)
// cout << " heading = " << heading_node->getDoubleValue()
// << " dist = " << nav_dist << endl;
//////////////////////////////////////////////////////////
// compute the target/selected radial in "true" heading
//////////////////////////////////////////////////////////
double trtrue = 0.0;
if ( is_loc ) {
// ILS localizers radials are already "true" in our
// database
trtrue = target_radial;
} else {
// VOR radials need to have that vor's offset added in
trtrue = target_radial + twist;
}
while ( trtrue < 0.0 ) { trtrue += 360.0; }
while ( trtrue > 360.0 ) { trtrue -= 360.0; }
target_radial_true_node->setDoubleValue( trtrue );
//////////////////////////////////////////////////////////
// adjust reception range for altitude
//////////////////////////////////////////////////////////
@ -548,16 +565,21 @@ FGNavRadio::update(double dt)
double ddist = last_loc_dist - loc_dist;
double dxtrack = last_xtrack_error - xtrack_error;
double a = atan2( dxtrack, ddist ) * SGD_RADIANS_TO_DEGREES;
SGPropertyNode *maghead
= fgGetNode("/orientation/heading-magnetic-deg", true);
cout << "heading = " << maghead->getDoubleValue()
if ( from_flag_node->getBoolValue() ) {
a = 180.0 - a;
if ( a > 180.0 ) { a -= 360.0; }
if ( a < -180.0 ) { a += 360.0; }
}
SGPropertyNode *true_hdg
= fgGetNode("/orientation/heading-deg", true);
cout << "true heading = " << true_hdg->getDoubleValue()
<< " selrad = " << sel_radial_node->getDoubleValue()
<< " artr = " << a
<< endl;
double est_hdg = sel_radial_node->getDoubleValue() + a;
double est_hdg = trtrue + a;
if ( est_hdg < 0.0 ) { est_hdg += 360.0; }
if ( est_hdg >= 360.0 ) { est_hdg -= 360.0; }
hdg_error = est_hdg - maghead->getDoubleValue();
hdg_error = est_hdg - true_hdg->getDoubleValue();
}
cdi_xtrack_hdg_err_node->setDoubleValue( hdg_error );
@ -632,21 +654,6 @@ FGNavRadio::update(double dt)
// a nav/ils radial.
//////////////////////////////////////////////////////////
// determine the target radial in "true" heading
double trtrue = 0.0;
if ( is_loc ) {
// ILS localizers radials are already "true" in our
// database
trtrue = target_radial;
} else {
// VOR radials need to have that vor's offset added in
trtrue = target_radial + twist;
}
while ( trtrue < 0.0 ) { trtrue += 360.0; }
while ( trtrue > 360.0 ) { trtrue -= 360.0; }
target_radial_true_node->setDoubleValue( trtrue );
// FIXME: this smells odd, there must be a better (or more
// linear) solution
//
@ -668,7 +675,7 @@ FGNavRadio::update(double dt)
// determine the target heading to fly to intercept the
// tgt_radial = target radial (true) + cdi offset adjustmest -
// xtrack heading error adjustment
double nta_hdg = trtrue + adjustment /* - hdg_error */;
double nta_hdg = trtrue + adjustment - hdg_error;
while ( nta_hdg < 0.0 ) { nta_hdg += 360.0; }
while ( nta_hdg > 360.0 ) { nta_hdg -= 360.0; }
target_auto_hdg_node->setDoubleValue( nta_hdg );