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Working on ironing out issues with VOR navigation. It think we are "as

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good as we can get" until we find a data source with actual VOR magnetic
offsets.  We can use VOR offsets from some fixed date, but not all VOR's
were installed on the same day so no matter what date we pick we will be off on most of them.
This commit is contained in:
curt 2001-02-02 05:25:45 +00:00
parent cbaf015481
commit 2827cf1387
7 changed files with 49 additions and 27 deletions
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8
src/Autopilot/newauto.cxx
View file

@ -375,10 +375,11 @@ int FGAutopilot::run() {
// localizers radials are "true"
tgt_radial = current_radiostack->get_nav1_radial();
} else {
tgt_radial = current_radiostack->get_nav1_radial()
+ FGBFI::getMagVar();
tgt_radial = current_radiostack->get_nav1_radial() +
current_radiostack->get_nav1_magvar();
}
cur_radial = current_radiostack->get_nav1_heading();
cur_radial = current_radiostack->get_nav1_heading() +
current_radiostack->get_nav1_magvar();
// cout << "target rad (true) = " << tgt_radial
// << " current rad (true) = " << cur_radial
// << endl;
@ -394,6 +395,7 @@ int FGAutopilot::run() {
TargetHeading = cur_radial - diff;
while ( TargetHeading < 0.0 ) { TargetHeading += 360.0; }
while ( TargetHeading > 360.0 ) { TargetHeading -= 360.0; }
MakeTargetHeadingStr( TargetHeading );
// cout << "target course (true) = " << TargetHeading << endl;
} else if ( heading_mode == FG_HEADING_WAYPOINT ) {
// update target heading to waypoint

2
src/Cockpit/radiostack.cxx
View file

@ -209,7 +209,7 @@ FGRadioStack::update()
geo_inverse_wgs_84( elev, lat * RAD_TO_DEG, lon * RAD_TO_DEG,
nav1_loclat, nav1_loclon,
&az1, &az2, &s );
cout << "az1 = " << az1 << " magvar = " << nav1_magvar << endl;
// cout << "az1 = " << az1 << " magvar = " << nav1_magvar << endl;
nav1_heading = az1 - nav1_magvar;
// Alex: nav1_heading = - (az1 - FGBFI::getMagVar() / RAD_TO_DEG);

2
src/Cockpit/radiostack.hxx
View file

@ -202,6 +202,7 @@ public:
inline double get_nav1_heading() const { return nav1_heading; }
inline double get_nav1_radial() const { return nav1_radial; }
inline double get_nav1_target_gs() const { return nav1_target_gs; }
inline double get_nav1_magvar() const { return nav1_magvar; }
inline bool get_nav2_inrange() const { return nav2_inrange; }
bool get_nav2_to_flag () const;
@ -225,6 +226,7 @@ public:
inline double get_nav2_heading() const { return nav2_heading; }
inline double get_nav2_radial() const { return nav2_radial; }
inline double get_nav2_target_gs() const { return nav2_target_gs; }
inline double get_nav2_magvar() const { return nav2_magvar; }
inline bool get_adf_inrange() const { return adf_inrange; }
inline double get_adf_lon() const { return adf_lon; }

35
src/Cockpit/steam.cxx
View file

@ -130,9 +130,6 @@ void FGSteam::update ( int timesteps )
_UpdatesPending += timesteps;
}
#undef DF1
#undef DF2
/* tc should be (elapsed_time_between_updates / desired_smoothing_time) */
void FGSteam::set_lowpass ( double *outthe, double inthe, double tc )
@ -169,11 +166,10 @@ void FGSteam::set_lowpass ( double *outthe, double inthe, double tc )
double pressInHgToAltFt(double p_inhg)
{
// Ref. Aviation Formulary, Ed Williams, www.best.com/~williams/avform.htm
const double P_0 = 29.92126; // Std. MSL pressure, inHg. (=10135.25 mb)
const double P_0 = 29.92126; // Std. MSL pressure, inHg. (=1013.25 mb)
const double p_Tr = 0.2233609 * P_0; // Pressure at tropopause, same units.
const double h_Tr = 36089.24; // Alt of tropopause, ft. (=11.0 km)
// return (P_0 - p_inhg) * 1000.0; // ### crude approx. for low alt's
if (p_inhg > p_Tr) // 0.0 to 11.0 km
return (1.0 - pow((p_inhg / P_0), 1.0 / 5.2558797)) / 6.8755856e-6;
return h_Tr + log10(p_inhg / p_Tr) / -4.806346e-5; // 11.0 to 20.0 km
@ -181,6 +177,21 @@ double pressInHgToAltFt(double p_inhg)
}
// Convert altitude to air pressure by ICAO Standard Atmosphere
double altFtToPressInHg(double alt_ft)
{
// Ref. Aviation Formulary, Ed Williams, www.best.com/~williams/avform.htm
const double P_0 = 29.92126; // Std. MSL pressure, inHg. (=1013.25 mb)
const double p_Tr = 0.2233609 * P_0; // Pressure at tropopause, same units.
const double h_Tr = 36089.24; // Alt of tropopause, ft. (=11.0 km)
if (alt_ft < h_Tr) // 0.0 to 11.0 km
return P_0 * pow(1.0 - 6.8755856e-6 * alt_ft, 5.2558797);
return p_Tr * exp(-4.806346e-5 * (alt_ft - h_Tr)); // 11.0 to 20.0 km
// We could put more code for higher altitudes here.
}
////////////////////////////////////////////////////////////////////////
// Here the fun really begins
@ -322,13 +333,7 @@ void FGSteam::_CatchUp()
We filter the actual value by one second to
account for the line impedance of the plumbing.
*/
double static_inhg = 29.92;
i = (int) FGBFI::getAltitude();
while ( i > 9000 )
{ static_inhg *= 0.707;
i -= 9000;
}
static_inhg *= ( 1.0 - 0.293 * i / 9000.0 );
double static_inhg = altFtToPressInHg(FGBFI::getAltitude());
set_lowpass ( & the_STATIC_inhg, static_inhg, dt );
/*
@ -429,9 +434,9 @@ double FGSteam::get_HackVOR1_deg () {
if ( current_radiostack->get_nav1_inrange() ) {
r = current_radiostack->get_nav1_heading()
- current_radiostack->get_nav1_radial();
cout << "Radial = " << current_radiostack->get_nav1_radial()
<< " Bearing = " << current_radiostack->get_nav1_heading()
<< endl;
// cout << "Radial = " << current_radiostack->get_nav1_radial()
// << " Bearing = " << current_radiostack->get_nav1_heading()
// << endl;
if (r> 180.0) r-=360.0; else
if (r<-180.0) r+=360.0;

5
src/Navaids/Makefile.am
View file

@ -8,6 +8,9 @@ libNavaids_a_SOURCES = \
nav.hxx navlist.hxx navlist.cxx
testnavs_SOURCES = testnavs.cxx
testnavs_LDADD = libNavaids.a -lsgmath -lsgmisc -lsgdebug -lsgmagvar -lz
testnavs_LDADD = \
libNavaids.a \
-lsgtiming -lsgmath -lsgmisc -lsgdebug -lsgmagvar \
-lz
INCLUDES += -I$(top_srcdir) -I$(top_srcdir)/src

21
src/Navaids/nav.hxx
View file

@ -30,6 +30,7 @@
#include <simgear/math/sg_geodesy.hxx>
#include <simgear/misc/fgstream.hxx>
#include <simgear/magvar/magvar.hxx>
#include <simgear/timing/sg_time.hxx>
#ifdef FG_HAVE_STD_INCLUDES
# include <istream>
@ -95,7 +96,16 @@ operator >> ( istream& in, FGNav& n )
double f;
char c /* , magvar_dir */ ;
string magvar_s;
static SGTime time_params;
static bool first_time = true;
static double julian_date = 0;
if ( first_time ) {
time_params.update( 0.0, 0.0, 0 );
julian_date = time_params.getJD();
first_time = false;
}
in >> n.type >> n.lat >> n.lon >> n.elev >> f >> n.range
>> c >> n.ident >> magvar_s;
@ -110,9 +120,12 @@ operator >> ( istream& in, FGNav& n )
// cout << "Calculating magvar for navaid " << n.ident << endl;
if (magvar_s == "XXX") {
// default to mag var as of 1990-01-01 (Julian 2447892.5)
n.magvar = -sgGetMagVar(n.lon * DEG_TO_RAD, n.lat * DEG_TO_RAD,
// cout << "lat = " << n.lat << " lon = " << n.lon << " elev = "
// << n.elev << " JD = "
// << julian_date << endl;
n.magvar = sgGetMagVar(n.lon * DEG_TO_RAD, n.lat * DEG_TO_RAD,
n.elev * FEET_TO_METER,
2447892.5) * RAD_TO_DEG;
julian_date) * RAD_TO_DEG;
// cout << "Default variation at " << n.lon << ',' << n.lat
// << " is " << var << endl;
#if 0
@ -134,7 +147,7 @@ operator >> ( istream& in, FGNav& n )
n.magvar = 0 - n.magvar;
// cout << "Explicit magvar of " << n.magvar << endl;
}
cout << n.ident << " " << n.magvar << endl;
// cout << n.ident << " " << n.magvar << endl;
// generate cartesian coordinates
Point3D geod( n.lon * DEG_TO_RAD, n.lat * DEG_TO_RAD, n.elev );

3
src/Navaids/navlist.cxx
View file

@ -45,9 +45,6 @@ FGNavList::~FGNavList( void ) {
bool FGNavList::init( FGPath path ) {
FGNav n;
SGTime time_params;
time_params.update( 0.0, 0.0, 0 );
navaids.erase( navaids.begin(), navaids.end() );
fg_gzifstream in( path.str() );