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flightgear/src/Instrumentation/heading_indicator_fg.cxx
ehofman d9bfd5a425 This should apply, and everything should build cleanly, in isolation from the
SimGear change. It changes all the SG_xxxx to be the 'real' includes, and gets
rid of many #ifdef SG_HAVE_STD_INCLUDES. As an added bonus, rather than
replacing 'SG_USING_NAMESPACE(std)' with 'using namespace std', I just fixed
the small number of places to use std:: explicitly. So we're no longer polluting
the global namespace with the entire contents of std, in many cases.

There is one more 'mechanical' change to come - getting rid of SG_USING_STD(X),
but I want to keep that separate from everything else. (There's another
mechnical change, replacing <math.h> with <cmath> and so on *everywhere*, but
one step at a time)
2008-07-25 18:38:29 +00:00

160 lines
4.9 KiB
C++

// heading_indicator_fg.cxx - a flux_gate compass.
// Based on the vacuum driven Heading Indicator Written by David Megginson, started 2002.
//
// Written by Vivian Meazza, started 2005.
//
// This file is in the Public Domain and comes with no warranty.
#include <simgear/compiler.h>
#include <iostream>
#include <string>
#include <sstream>
#include "heading_indicator_fg.hxx"
#include <Main/fg_props.hxx>
#include <Main/util.hxx>
HeadingIndicatorFG::HeadingIndicatorFG ( SGPropertyNode *node )
:
name("heading-indicator-fg"),
num(0)
{
int i;
for ( i = 0; i < node->nChildren(); ++i ) {
SGPropertyNode *child = node->getChild(i);
string cname = child->getName();
string cval = child->getStringValue();
if ( cname == "name" ) {
name = cval;
} else if ( cname == "number" ) {
num = child->getIntValue();
} else {
SG_LOG( SG_INSTR, SG_WARN, "Error in flux-gate heading-indicator config logic" );
if ( name.length() ) {
SG_LOG( SG_INSTR, SG_WARN, "Section = " << name );
}
}
}
}
HeadingIndicatorFG::HeadingIndicatorFG ()
{
}
HeadingIndicatorFG::~HeadingIndicatorFG ()
{
}
void
HeadingIndicatorFG::init ()
{
string branch;
branch = "/instrumentation/" + name;
_heading_in_node = fgGetNode("/orientation/heading-deg", true);
SGPropertyNode *node = fgGetNode(branch.c_str(), num, true );
_offset_node = node->getChild("offset-deg", 0, true);
_serviceable_node = node->getChild("serviceable", 0, true);
_error_node = node->getChild("heading-bug-error-deg", 0, true);
_nav1_error_node = node->getChild("nav1-course-error-deg", 0, true);
_heading_out_node = node->getChild("indicated-heading-deg", 0, true);
_last_heading_deg = (_heading_in_node->getDoubleValue() +
_offset_node->getDoubleValue());
_electrical_node = fgGetNode("/systems/electrical/outputs/DG", true);
}
void
HeadingIndicatorFG::bind ()
{
std::ostringstream temp;
string branch;
temp << num;
branch = "/instrumentation/" + name + "[" + temp.str() + "]";
fgTie((branch + "/serviceable").c_str(),
&_gyro, &Gyro::is_serviceable, &Gyro::set_serviceable);
fgTie((branch + "/spin").c_str(),
&_gyro, &Gyro::get_spin_norm, &Gyro::set_spin_norm);
}
void
HeadingIndicatorFG::unbind ()
{
std::ostringstream temp;
string branch;
temp << num;
branch = "/instrumentation/" + name + "[" + temp.str() + "]";
fgUntie((branch + "/serviceable").c_str());
fgUntie((branch + "/spin").c_str());
}
void
HeadingIndicatorFG::update (double dt)
{
// Get the spin from the gyro
_gyro.set_power_norm(_electrical_node->getDoubleValue());
_gyro.update(dt);
double spin = _gyro.get_spin_norm();
// No time-based precession for a flux gate compass
// We just use offset to get the magvar
double offset = _offset_node->getDoubleValue();
// TODO: movement-induced error
// Next, calculate the indicated heading,
// introducing errors.
double factor = 0.01 / (spin * spin * spin * spin * spin * spin);
double heading = _heading_in_node->getDoubleValue();
// Now, we have to get the current
// heading and the last heading into
// the same range.
while ((heading - _last_heading_deg) > 180)
_last_heading_deg += 360;
while ((heading - _last_heading_deg) < -180)
_last_heading_deg -= 360;
heading = fgGetLowPass(_last_heading_deg, heading, dt/factor);
_last_heading_deg = heading;
heading += offset;
while (heading < 0)
heading += 360;
while (heading > 360)
heading -= 360;
_heading_out_node->setDoubleValue(heading);
// calculate the difference between the indicated heading
// and the selected heading for use with an autopilot
static SGPropertyNode *bnode
= fgGetNode( "/autopilot/settings/heading-bug-deg", false );
double diff = 0;
if ( bnode ){
diff = bnode->getDoubleValue() - heading;
if ( diff < -180.0 ) { diff += 360.0; }
if ( diff > 180.0 ) { diff -= 360.0; }
_error_node->setDoubleValue( diff );
}
// calculate the difference between the indicated heading
// and the selected nav1 radial for use with an autopilot
SGPropertyNode *nnode
= fgGetNode( "/instrumentation/nav/radials/selected-deg", true );
double ndiff = 0;
if ( nnode ){
ndiff = nnode->getDoubleValue() - heading;
if ( ndiff < -180.0 ) { ndiff += 360.0; }
if ( ndiff > 180.0 ) { ndiff -= 360.0; }
_nav1_error_node->setDoubleValue( ndiff );
}
}
// end of heading_indicator_fg.cxx