-// heading_indicator_dg.cxx - a Directional Gyro (DG) compass.\r
-// Based on the vacuum driven Heading Indicator Written by David Megginson,\r
-// started 2002.\r
-//\r
-// Written by Vivian Meazza, started 2005.\r
-//\r
-// This file is in the Public Domain and comes with no warranty.\r
-\r
-#include <simgear/compiler.h>\r
-#include <simgear/sg_inlines.h>\r
-#include <iostream>\r
-#include <string>\r
-#include <sstream>\r
-\r
-#include <Main/fg_props.hxx>\r
-#include <Main/util.hxx>\r
-\r
-#include "heading_indicator_dg.hxx"\r
-\r
-\r
-HeadingIndicatorDG::HeadingIndicatorDG ( SGPropertyNode *node ) :\r
- name("heading-indicator-dg"),\r
- num(0)\r
-{\r
- int i;\r
- for ( i = 0; i < node->nChildren(); ++i ) {\r
- SGPropertyNode *child = node->getChild(i);\r
- string cname = child->getName();\r
- string cval = child->getStringValue();\r
- if ( cname == "name" ) {\r
- name = cval;\r
- } else if ( cname == "number" ) {\r
- num = child->getIntValue();\r
- } else {\r
- SG_LOG( SG_INSTR, SG_WARN, "Error in DG heading-indicator config logic" );\r
- if ( name.length() ) {\r
- SG_LOG( SG_INSTR, SG_WARN, "Section = " << name );\r
- }\r
- }\r
- }\r
-}\r
-\r
-HeadingIndicatorDG::HeadingIndicatorDG ()\r
-{\r
-}\r
-\r
-HeadingIndicatorDG::~HeadingIndicatorDG ()\r
-{\r
-}\r
-\r
-void\r
-HeadingIndicatorDG::init ()\r
-{\r
- string branch;\r
- branch = "/instrumentation/" + name;\r
-\r
+// heading_indicator_dg.cxx - a Directional Gyro (DG) 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.
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <simgear/compiler.h>
+#include <simgear/sg_inlines.h>
+#include <simgear/math/SGMath.hxx>
+#include <iostream>
+#include <string>
+#include <sstream>
+
+#include <Main/fg_props.hxx>
+#include <Main/util.hxx>
+
+#include "heading_indicator_dg.hxx"
+
+/** Macro calculating x^6 (faster than super-slow math/pow). */
+#define POW6(x) (x*x*x*x*x*x)
+
+HeadingIndicatorDG::HeadingIndicatorDG ( SGPropertyNode *node ) :
+ name("heading-indicator-dg"),
+ num(0)
+{
+ int i;
+ for ( i = 0; i < node->nChildren(); ++i ) {
+ SGPropertyNode *child = node->getChild(i);
+ std::string cname = child->getName();
+ std::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 DG heading-indicator config logic" );
+ if ( name.length() ) {
+ SG_LOG( SG_INSTR, SG_WARN, "Section = " << name );
+ }
+ }
+ }
+}
+
+HeadingIndicatorDG::~HeadingIndicatorDG ()
+{
+}
+
+void
+HeadingIndicatorDG::init ()
+{
+ std::string branch;
+ branch = "/instrumentation/" + name;
+
_heading_in_node = fgGetNode("/orientation/heading-deg", true);
_yaw_rate_node = fgGetNode("/orientation/yaw-rate-degps", true);
- _g_node = fgGetNode("/accelerations/pilot-g", true);
-
-\r
- SGPropertyNode *node = fgGetNode(branch.c_str(), num, true );\r
- _offset_node = node->getChild("offset-deg", 0, true);\r
- _serviceable_node = node->getChild("serviceable", 0, true);\r
- _heading_bug_error_node = node->getChild("heading-bug-error-deg", 0, true);\r
- _error_node = node->getChild("error-deg", 0, true);\r
- _nav1_error_node = node->getChild("nav1-course-error-deg", 0, true);\r
- _heading_out_node = node->getChild("indicated-heading-deg", 0, true);\r
- _align_node = node->getChild("align-deg", 0, true);\r
-\r
- _electrical_node = fgGetNode("/systems/electrical/outputs/DG", true);\r
-\r
- _align_node->setDoubleValue(0);\r
- _error_node->setDoubleValue(0);\r
-\r
- _last_heading_deg = (_heading_in_node->getDoubleValue() +\r
- _offset_node->getDoubleValue() + _align_node->getDoubleValue());\r
-}\r
-\r
-void\r
-HeadingIndicatorDG::bind ()\r
-{\r
- std::ostringstream temp;\r
- string branch;\r
- temp << num;\r
- branch = "/instrumentation/" + name + "[" + temp.str() + "]";\r
-\r
- fgTie((branch + "/serviceable").c_str(),\r
- &_gyro, &Gyro::is_serviceable, &Gyro::set_serviceable);\r
- fgTie((branch + "/spin").c_str(),\r
- &_gyro, &Gyro::get_spin_norm, &Gyro::set_spin_norm);\r
-}\r
-\r
-void\r
-HeadingIndicatorDG::unbind ()\r
-{\r
- std::ostringstream temp;\r
- string branch;\r
- temp << num;\r
- branch = "/instrumentation/" + name + "[" + temp.str() + "]";\r
-\r
- fgUntie((branch + "/serviceable").c_str());\r
- fgUntie((branch + "/spin").c_str());\r
-}\r
-\r
-void\r
-HeadingIndicatorDG::update (double dt)\r
-{\r
- // Get the spin from the gyro\r
- _gyro.set_power_norm(_electrical_node->getDoubleValue());\r
-\r
- _gyro.update(dt);\r
- double spin = _gyro.get_spin_norm();\r
-\r
- // Next, calculate time-based precession\r
- double offset = _offset_node->getDoubleValue();\r
- offset -= dt * (0.25 / 60.0); // 360deg/day\r
- SG_NORMALIZE_RANGE(offset, -360.0, 360.0);\r
-\r
- // No magvar - set the alignment manually\r
- double align = _align_node->getDoubleValue();\r
-\r
- // Movement-induced error\r
- double yaw_rate = _yaw_rate_node->getDoubleValue();\r
- double error = _error_node->getDoubleValue();\r
- double g = _g_node->getDoubleValue();
- int sign = 0;
+ _g_node = fgGetNode("/accelerations/pilot-g", true);
+
+ SGPropertyNode *node = fgGetNode(branch.c_str(), num, true );
+ _offset_node = node->getChild("offset-deg", 0, true);
+ _serviceable_node = node->getChild("serviceable", 0, true);
+ _heading_bug_error_node = node->getChild("heading-bug-error-deg", 0, true);
+ _error_node = node->getChild("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);
+ _align_node = node->getChild("align-deg", 0, true);
+
+ _electrical_node = fgGetNode("/systems/electrical/outputs/DG", true);
+
+ reinit();
+}
+
+void
+HeadingIndicatorDG::bind ()
+{
+ std::ostringstream temp;
+ std::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
+HeadingIndicatorDG::unbind ()
+{
+ std::ostringstream temp;
+ std::string branch;
+ temp << num;
+ branch = "/instrumentation/" + name + "[" + temp.str() + "]";
+
+ fgUntie((branch + "/serviceable").c_str());
+ fgUntie((branch + "/spin").c_str());
+}
+
+void
+HeadingIndicatorDG::reinit (void)
+{
+ // reset errors/drift values
+ _align_node->setDoubleValue(0.0);
+ _error_node->setDoubleValue(0.0);
+ _offset_node->setDoubleValue(0.0);
+ _last_heading_deg = _heading_in_node->getDoubleValue();
+ _last_indicated_heading_dg = _last_heading_deg;
+
+ _gyro.reinit();
+}
+
+void
+HeadingIndicatorDG::update (double dt)
+{
+ // Get the spin from the gyro
+ _gyro.set_power_norm(_electrical_node->getDoubleValue());
+
+ _gyro.update(dt);
+
+ // read inputs
+ double spin = _gyro.get_spin_norm();
+ double heading = _heading_in_node->getDoubleValue();
+ double offset = _offset_node->getDoubleValue();
+
+ // calculate scaling factor
+ double factor = POW6(spin);
+
+ // calculate time-based precession (scaled by spin factor, since
+ // there is no precession when the gyro is stuck).
+ offset -= dt * (0.25 / 60.0) * factor; // 360deg/day
+
+ // indication should get more and more stuck at low gyro spins
+ if (spin < 0.9)
+ {
+ // when gyro spin is low, then any heading change results in
+ // increasing the offset
+ double diff = SGMiscd::normalizePeriodic(-180.0, 180.0, _last_heading_deg - heading);
+ // scaled by 1-factor, so indication is fully stuck at spin==0 (offset compensates
+ // any heading change)
+ offset += diff * (1.0-factor);
+ }
+ _last_heading_deg = heading;
+
+ // normalize offset
+ offset = SGMiscd::normalizePeriodic(-180.0,180.0,offset);
+ _offset_node->setDoubleValue(offset);
+
+ // No magvar - set the alignment manually
+ double align = _align_node->getDoubleValue();
+
+ // Movement-induced error
+ double yaw_rate = _yaw_rate_node->getDoubleValue();
+ double error = _error_node->getDoubleValue();
+ double g = _g_node->getDoubleValue();
if ( fabs ( yaw_rate ) > 5 ) {
- sign = (yaw_rate < 0 ? -1 : 1);
- error += 0.033 * -yaw_rate * dt ;
+ error += 0.033 * -yaw_rate * dt * factor;
}
if ( g > 1.5 || g < -0.5){
- sign = (g < 0 ? -1 : 1);
- error += 0.033 * g * dt;
+ error += 0.033 * g * dt * factor;
}
-
_error_node->setDoubleValue(error);
- // Next, calculate the indicated heading,\r
- // introducing errors.\r
- double factor = 100 * (spin * spin * spin * spin * spin * spin);\r
- double heading = _heading_in_node->getDoubleValue();\r
-\r
- // Now, we have to get the current\r
- // heading and the last heading into\r
- // the same range.\r
- while ((heading - _last_heading_deg) > 180)\r
- _last_heading_deg += 360;\r
- while ((heading - _last_heading_deg) < -180)\r
- _last_heading_deg -= 360;\r
-\r
- heading = fgGetLowPass(_last_heading_deg, heading, dt * factor);\r
- _last_heading_deg = heading;\r
-\r
- heading += offset + align + error;\r
- SG_NORMALIZE_RANGE(heading, 0.0, 360.0);\r
-\r
- _heading_out_node->setDoubleValue(heading);\r
-\r
- // calculate the difference between the indicacted heading\r
- // and the selected heading for use with an autopilot\r
- static SGPropertyNode *bnode\r
- = fgGetNode( "/autopilot/settings/heading-bug-deg", false );\r
- if ( bnode ) {\r
- double diff = bnode->getDoubleValue() - heading;\r
- if ( diff < -180.0 ) { diff += 360.0; }\r
- if ( diff > 180.0 ) { diff -= 360.0; }\r
- _heading_bug_error_node->setDoubleValue( diff );\r
- }\r
- // calculate the difference between the indicated heading\r
- // and the selected nav1 radial for use with an autopilot\r
- SGPropertyNode *nnode\r
- = fgGetNode( "/instrumentation/nav/radials/selected-deg", false );\r
- if ( nnode ) {\r
- double diff = nnode->getDoubleValue() - heading;\r
- if ( diff < -180.0 ) { diff += 360.0; }\r
- if ( diff > 180.0 ) { diff -= 360.0; }\r
- _nav1_error_node->setDoubleValue( diff );\r
- }\r
-}\r
-\r
-// end of heading_indicator_dg.cxx\r
+ // Now, we have to get the current
+ // heading and the last heading into
+ // the same range.
+ while ((heading - _last_indicated_heading_dg) > 180)
+ _last_indicated_heading_dg += 360;
+ while ((heading - _last_indicated_heading_dg) < -180)
+ _last_indicated_heading_dg -= 360;
+ heading = fgGetLowPass(_last_indicated_heading_dg, heading, dt * 100);
+ _last_indicated_heading_dg = heading;
+
+ heading += offset + align + error;
+ heading = SGMiscd::normalizePeriodic(0.0,360.0,heading);
+
+ _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 );
+ if ( bnode ) {
+ double diff = bnode->getDoubleValue() - heading;
+ if ( diff < -180.0 ) { diff += 360.0; }
+ if ( diff > 180.0 ) { diff -= 360.0; }
+ _heading_bug_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", false );
+ if ( nnode ) {
+ double diff = nnode->getDoubleValue() - heading;
+ if ( diff < -180.0 ) { diff += 360.0; }
+ if ( diff > 180.0 ) { diff -= 360.0; }
+ _nav1_error_node->setDoubleValue( diff );
+ }
+}
+
+// end of heading_indicator_dg.cxx
projects / flightgear.git / blobdiff