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flightgear/src/Instrumentation/gps.cxx
mfranz b9e4775a7a Roy Vegard Ovesen: 
- finish cleanup/optimization of instrumentation system (started by mfranz)
- improve configuration of special properties by
  addressing them directly
2006-12-06 22:11:43 +00:00

692 lines
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// gps.cxx - distance-measuring equipment.
// Written by David Megginson, started 2003.
//
// 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 <Aircraft/aircraft.hxx>
#include <simgear/route/route.hxx>
#include <simgear/math/sg_random.h>
#include <simgear/sg_inlines.h>
#include <Airports/simple.hxx>
#include <Main/fg_init.hxx>
#include <Main/globals.hxx>
#include <Main/fg_props.hxx>
#include <Main/util.hxx>
#include <Navaids/fixlist.hxx>
#include <Navaids/navlist.hxx>
#include "gps.hxx"
SG_USING_STD(string);
GPS::GPS ( SGPropertyNode *node)
: _last_valid(false),
_last_longitude_deg(0),
_last_latitude_deg(0),
_last_altitude_m(0),
_last_speed_kts(0),
_wp0_latitude_deg(0),
_wp0_longitude_deg(0),
_wp0_altitude_m(0),
_wp1_latitude_deg(0),
_wp1_longitude_deg(0),
_wp1_altitude_m(0),
_alt_dist_ratio(0),
_distance_m(0),
_course_deg(0),
_name(node->getStringValue("name", "gps")),
_num(node->getIntValue("number", 0))
{
}
GPS::~GPS ()
{
}
void
GPS::init ()
{
route = new SGRoute;
route->clear();
string branch;
branch = "/instrumentation/" + _name;
SGPropertyNode *node = fgGetNode(branch.c_str(), _num, true );
_longitude_node = fgGetNode("/position/longitude-deg", true);
_latitude_node = fgGetNode("/position/latitude-deg", true);
_altitude_node = fgGetNode("/position/altitude-ft", true);
_magvar_node = fgGetNode("/environment/magnetic-variation-deg", true);
_serviceable_node = node->getChild("serviceable", 0, true);
_electrical_node = fgGetNode("/systems/electrical/outputs/gps", true);
SGPropertyNode *wp_node = node->getChild("wp", 0, true);
SGPropertyNode *wp0_node = wp_node->getChild("wp", 0, true);
SGPropertyNode *wp1_node = wp_node->getChild("wp", 1, true);
addWp = wp1_node->getChild("Add-to-route", 0, true);
_wp0_longitude_node = wp0_node->getChild("longitude-deg", 0, true);
_wp0_latitude_node = wp0_node->getChild("latitude-deg", 0, true);
_wp0_altitude_node = wp0_node->getChild("altitude-ft", 0, true);
_wp0_ID_node = wp0_node->getChild("ID", 0, true);
_wp0_name_node = wp0_node->getChild("name", 0, true);
_wp0_course_node = wp0_node->getChild("desired-course-deg", 0, true);
_wp0_waypoint_type_node = wp0_node->getChild("waypoint-type", 0, true);
_wp0_distance_node = wp0_node->getChild("distance-nm", 0, true);
_wp0_ttw_node = wp0_node->getChild("TTW", 0, true);
_wp0_bearing_node = wp0_node->getChild("bearing-true-deg", 0, true);
_wp0_mag_bearing_node = wp0_node->getChild("bearing-mag-deg", 0, true);
_wp0_course_deviation_node =
wp0_node->getChild("course-deviation-deg", 0, true);
_wp0_course_error_nm_node = wp0_node->getChild("course-error-nm", 0, true);
_wp0_to_flag_node = wp0_node->getChild("to-flag", 0, true);
_true_wp0_bearing_error_node =
wp0_node->getChild("true-bearing-error-deg", 0, true);
_magnetic_wp0_bearing_error_node =
wp0_node->getChild("magnetic-bearing-error-deg", 0, true);
_wp1_longitude_node = wp1_node->getChild("longitude-deg", 0, true);
_wp1_latitude_node = wp1_node->getChild("latitude-deg", 0, true);
_wp1_altitude_node = wp1_node->getChild("altitude-ft", 0, true);
_wp1_ID_node = wp1_node->getChild("ID", 0, true);
_wp1_name_node = wp1_node->getChild("name", 0, true);
_wp1_course_node = wp1_node->getChild("desired-course-deg", 0, true);
_wp1_waypoint_type_node = wp1_node->getChild("waypoint-type", 0, true);
_wp1_distance_node = wp1_node->getChild("distance-nm", 0, true);
_wp1_ttw_node = wp1_node->getChild("TTW", 0, true);
_wp1_bearing_node = wp1_node->getChild("bearing-true-deg", 0, true);
_wp1_mag_bearing_node = wp1_node->getChild("bearing-mag-deg", 0, true);
_wp1_course_deviation_node =
wp1_node->getChild("course-deviation-deg", 0, true);
_wp1_course_error_nm_node = wp1_node->getChild("course-error-nm", 0, true);
_wp1_to_flag_node = wp1_node->getChild("to-flag", 0, true);
_true_wp1_bearing_error_node =
wp1_node->getChild("true-bearing-error-deg", 0, true);
_magnetic_wp1_bearing_error_node =
wp1_node->getChild("magnetic-bearing-error-deg", 0, true);
_get_nearest_airport_node =
wp1_node->getChild("get-nearest-airport", 0, true);
_tracking_bug_node = node->getChild("tracking-bug", 0, true);
_raim_node = node->getChild("raim", 0, true);
_indicated_longitude_node =
node->getChild("indicated-longitude-deg", 0, true);
_indicated_latitude_node =
node->getChild("indicated-latitude-deg", 0, true);
_indicated_altitude_node =
node->getChild("indicated-altitude-ft", 0, true);
_indicated_vertical_speed_node =
node->getChild("indicated-vertical-speed", 0, true);
_true_track_node =
node->getChild("indicated-track-true-deg", 0, true);
_magnetic_track_node =
node->getChild("indicated-track-magnetic-deg", 0, true);
_speed_node =
node->getChild("indicated-ground-speed-kt", 0, true);
_odometer_node =
node->getChild("odometer", 0, true);
_trip_odometer_node =
node->getChild("trip-odometer", 0, true);
_true_bug_error_node =
node->getChild("true-bug-error-deg", 0, true);
_magnetic_bug_error_node =
node->getChild("magnetic-bug-error-deg", 0, true);
_leg_distance_node =
wp_node->getChild("leg-distance-nm", 0, true);
_leg_course_node =
wp_node->getChild("leg-true-course-deg", 0, true);
_leg_magnetic_course_node =
wp_node->getChild("leg-mag-course-deg", 0, true);
_alt_dist_ratio_node =
wp_node->getChild("alt-dist-ratio", 0, true);
_leg_course_deviation_node =
wp_node->getChild("leg-course-deviation-deg", 0, true);
_leg_course_error_nm_node =
wp_node->getChild("leg-course-error-nm", 0, true);
_leg_to_flag_node =
wp_node->getChild("leg-to-flag", 0, true);
_alt_deviation_node =
wp_node->getChild("alt-deviation-ft", 0, true);
_route = node->getChild("route", 0, true);
popWp = _route->getChild("Pop-WP", 0, true);
addWp->setBoolValue(false);
popWp->setBoolValue(false);
_serviceable_node->setBoolValue(true);
}
void
GPS::update (double delta_time_sec)
{
// If it's off, don't bother.
if (!_serviceable_node->getBoolValue() ||
!_electrical_node->getBoolValue()) {
_last_valid = false;
_last_longitude_deg = 0;
_last_latitude_deg = 0;
_last_altitude_m = 0;
_last_speed_kts = 0;
_raim_node->setDoubleValue(false);
_indicated_longitude_node->setDoubleValue(0);
_indicated_latitude_node->setDoubleValue(0);
_indicated_altitude_node->setDoubleValue(0);
_indicated_vertical_speed_node->setDoubleValue(0);
_true_track_node->setDoubleValue(0);
_magnetic_track_node->setDoubleValue(0);
_speed_node->setDoubleValue(0);
_wp1_distance_node->setDoubleValue(0);
_wp1_bearing_node->setDoubleValue(0);
_wp1_longitude_node->setDoubleValue(0);
_wp1_latitude_node->setDoubleValue(0);
_wp1_course_node->setDoubleValue(0);
_odometer_node->setDoubleValue(0);
_trip_odometer_node->setDoubleValue(0);
_tracking_bug_node->setDoubleValue(0);
_true_bug_error_node->setDoubleValue(0);
_magnetic_bug_error_node->setDoubleValue(0);
_true_wp1_bearing_error_node->setDoubleValue(0);
_magnetic_wp1_bearing_error_node->setDoubleValue(0);
return;
}
// Get the aircraft position
// TODO: Add noise and other errors.
double longitude_deg = _longitude_node->getDoubleValue();
double latitude_deg = _latitude_node->getDoubleValue();
double altitude_m = _altitude_node->getDoubleValue() * SG_FEET_TO_METER;
double magvar_deg = _magvar_node->getDoubleValue();
/*
// Bias and random error
double random_factor = sg_random();
double random_error = 1.4;
double error_radius = 5.1;
double bias_max_radius = 5.1;
double random_max_radius = 1.4;
bias_length += (random_factor-0.5) * 1.0e-3;
if (bias_length <= 0.0) bias_length = 0.0;
else if (bias_length >= bias_max_radius) bias_length = bias_max_radius;
bias_angle += (random_factor-0.5) * 1.0e-3;
if (bias_angle <= 0.0) bias_angle = 0.0;
else if (bias_angle >= 360.0) bias_angle = 360.0;
double random_length = random_factor * random_max_radius;
double random_angle = random_factor * 360.0;
double bias_x = bias_length * cos(bias_angle * SG_PI / 180.0);
double bias_y = bias_length * sin(bias_angle * SG_PI / 180.0);
double random_x = random_length * cos(random_angle * SG_PI / 180.0);
double random_y = random_length * sin(random_angle * SG_PI / 180.0);
double error_x = bias_x + random_x;
double error_y = bias_y + random_y;
double error_length = sqrt(error_x*error_x + error_y*error_y);
double error_angle = atan(error_y / error_x) * 180.0 / SG_PI;
double lat2;
double lon2;
double az2;
geo_direct_wgs_84 ( altitude_m, latitude_deg,
longitude_deg, error_angle,
error_length, &lat2, &lon2,
&az2 );
//cout << lat2 << " " << lon2 << endl;
printf("%f %f \n", bias_length, bias_angle);
printf("%3.7f %3.7f \n", lat2, lon2);
printf("%f %f \n", error_length, error_angle);
*/
double speed_kt, vertical_speed_mpm;
_raim_node->setBoolValue(true);
_indicated_longitude_node->setDoubleValue(longitude_deg);
_indicated_latitude_node->setDoubleValue(latitude_deg);
_indicated_altitude_node->setDoubleValue(altitude_m * SG_METER_TO_FEET);
if (_last_valid) {
double track1_deg, track2_deg, distance_m, odometer, mag_track_bearing;
geo_inverse_wgs_84(altitude_m,
_last_latitude_deg, _last_longitude_deg,
latitude_deg, longitude_deg,
&track1_deg, &track2_deg, &distance_m);
speed_kt = ((distance_m * SG_METER_TO_NM) *
((1 / delta_time_sec) * 3600.0));
vertical_speed_mpm = ((altitude_m - _last_altitude_m) * 60 /
delta_time_sec);
_indicated_vertical_speed_node->setDoubleValue
(vertical_speed_mpm * SG_METER_TO_FEET);
_true_track_node->setDoubleValue(track1_deg);
mag_track_bearing = track1_deg - magvar_deg;
SG_NORMALIZE_RANGE(mag_track_bearing, 0.0, 360.0);
_magnetic_track_node->setDoubleValue(mag_track_bearing);
speed_kt = fgGetLowPass(_last_speed_kts, speed_kt, delta_time_sec/20.0);
_last_speed_kts = speed_kt;
_speed_node->setDoubleValue(speed_kt);
odometer = _odometer_node->getDoubleValue();
_odometer_node->setDoubleValue(odometer + distance_m * SG_METER_TO_NM);
odometer = _trip_odometer_node->getDoubleValue();
_trip_odometer_node->setDoubleValue(odometer + distance_m * SG_METER_TO_NM);
// Get waypoint 0 position
double wp0_longitude_deg = _wp0_longitude_node->getDoubleValue();
double wp0_latitude_deg = _wp0_latitude_node->getDoubleValue();
double wp0_altitude_m = _wp0_altitude_node->getDoubleValue()
* SG_FEET_TO_METER;
double wp0_course_deg = _wp0_course_node->getDoubleValue();
double wp0_distance, wp0_bearing_deg, wp0_course_deviation_deg,
wp0_course_error_m, wp0_TTW, wp0_bearing_error_deg;
string wp0_ID = _wp0_ID_node->getStringValue();
// Get waypoint 1 position
double wp1_longitude_deg = _wp1_longitude_node->getDoubleValue();
double wp1_latitude_deg = _wp1_latitude_node->getDoubleValue();
double wp1_altitude_m = _wp1_altitude_node->getDoubleValue()
* SG_FEET_TO_METER;
double wp1_course_deg = _wp1_course_node->getDoubleValue();
double wp1_distance, wp1_bearing_deg, wp1_course_deviation_deg,
wp1_course_error_m, wp1_TTW, wp1_bearing_error_deg;
string wp1_ID = _wp1_ID_node->getStringValue();
// If the get-nearest-airport-node is true.
// Get the nearest airport, and set it as waypoint 1.
if (_get_nearest_airport_node->getBoolValue()) {
const FGAirport* a = globals->get_airports()->search(longitude_deg, latitude_deg, false);
if(a) {
_wp1_ID_node->setStringValue(a->getId().c_str());
wp1_longitude_deg = a->getLongitude();
wp1_latitude_deg = a->getLatitude();
_wp1_name_node->setStringValue(a->getName().c_str());
_get_nearest_airport_node->setBoolValue(false);
_last_wp1_ID = wp1_ID = a->getId().c_str();
}
}
// If the waypoint 0 ID has changed, try to find the new ID
// in the airport-, fix-, nav-database.
if ( !(_last_wp0_ID == wp0_ID) ) {
string waypont_type =
_wp0_waypoint_type_node->getStringValue();
if (waypont_type == "airport") {
const FGAirport* a = globals->get_airports()->search( wp0_ID );
if ( a ) {
wp0_longitude_deg = a->getLongitude();
wp0_latitude_deg = a->getLatitude();
_wp0_name_node->setStringValue(a->getName().c_str());
}
}
else if (waypont_type == "nav") {
FGNavRecord *n
= globals->get_navlist()->findByIdent(wp0_ID.c_str(),
longitude_deg,
latitude_deg);
if ( n != NULL ) {
//cout << "Nav found" << endl;
wp0_longitude_deg = n->get_lon();
wp0_latitude_deg = n->get_lat();
_wp0_name_node->setStringValue(n->get_name().c_str());
}
}
else if (waypont_type == "fix") {
FGFix f;
if ( globals->get_fixlist()->query(wp0_ID, &f) ) {
//cout << "Fix found" << endl;
wp0_longitude_deg = f.get_lon();
wp0_latitude_deg = f.get_lat();
_wp0_name_node->setStringValue(wp0_ID.c_str());
}
}
_last_wp0_ID = wp0_ID;
}
// If the waypoint 1 ID has changed, try to find the new ID
// in the airport-, fix-, nav-database.
if ( !(_last_wp1_ID == wp1_ID) ) {
string waypont_type =
_wp1_waypoint_type_node->getStringValue();
if (waypont_type == "airport") {
const FGAirport* a = globals->get_airports()->search( wp1_ID );
if ( a ) {
wp1_longitude_deg = a->getLongitude();
wp1_latitude_deg = a->getLatitude();
_wp1_name_node->setStringValue(a->getName().c_str());
}
}
else if (waypont_type == "nav") {
FGNavRecord *n
= globals->get_navlist()->findByIdent(wp1_ID.c_str(),
longitude_deg,
latitude_deg);
if ( n != NULL ) {
//cout << "Nav found" << endl;
wp1_longitude_deg = n->get_lon();
wp1_latitude_deg = n->get_lat();
_wp1_name_node->setStringValue(n->get_name().c_str());
}
}
else if (waypont_type == "fix") {
FGFix f;
if ( globals->get_fixlist()->query(wp1_ID, &f) ) {
//cout << "Fix found" << endl;
wp1_longitude_deg = f.get_lon();
wp1_latitude_deg = f.get_lat();
_wp1_name_node->setStringValue(wp1_ID.c_str());
}
}
_last_wp1_ID = wp1_ID;
}
// If any of the two waypoints have changed
// we need to calculate a new course between them,
// and values for vertical navigation.
if ( wp0_longitude_deg != _wp0_longitude_deg ||
wp0_latitude_deg != _wp0_latitude_deg ||
wp0_altitude_m != _wp0_altitude_m ||
wp1_longitude_deg != _wp1_longitude_deg ||
wp1_latitude_deg != _wp1_latitude_deg ||
wp1_altitude_m != _wp1_altitude_m )
{
// Update the global variables
_wp0_longitude_deg = wp0_longitude_deg;
_wp0_latitude_deg = wp0_latitude_deg;
_wp0_altitude_m = wp0_altitude_m;
_wp1_longitude_deg = wp1_longitude_deg;
_wp1_latitude_deg = wp1_latitude_deg;
_wp1_altitude_m = wp1_altitude_m;
// Get the course and distance from wp0 to wp1
SGWayPoint wp0(wp0_longitude_deg,
wp0_latitude_deg, wp0_altitude_m);
SGWayPoint wp1(wp1_longitude_deg,
wp1_latitude_deg, wp1_altitude_m);
wp1.CourseAndDistance(wp0, &_course_deg, &_distance_m);
double leg_mag_course = _course_deg - magvar_deg;
SG_NORMALIZE_RANGE(leg_mag_course, 0.0, 360.0);
// Get the altitude / distance ratio
if ( distance_m > 0.0 ) {
double alt_difference_m = wp0_altitude_m - wp1_altitude_m;
_alt_dist_ratio = alt_difference_m / _distance_m;
}
_leg_distance_node->setDoubleValue(_distance_m * SG_METER_TO_NM);
_leg_course_node->setDoubleValue(_course_deg);
_leg_magnetic_course_node->setDoubleValue(leg_mag_course);
_alt_dist_ratio_node->setDoubleValue(_alt_dist_ratio);
_wp0_longitude_node->setDoubleValue(wp0_longitude_deg);
_wp0_latitude_node->setDoubleValue(wp0_latitude_deg);
_wp1_longitude_node->setDoubleValue(wp1_longitude_deg);
_wp1_latitude_node->setDoubleValue(wp1_latitude_deg);
}
// Find the bearing and distance to waypoint 0.
SGWayPoint wp0(wp0_longitude_deg, wp0_latitude_deg, wp0_altitude_m);
wp0.CourseAndDistance(longitude_deg, latitude_deg, altitude_m,
&wp0_bearing_deg, &wp0_distance);
_wp0_distance_node->setDoubleValue(wp0_distance * SG_METER_TO_NM);
_wp0_bearing_node->setDoubleValue(wp0_bearing_deg);
double wp0_mag_bearing_deg = wp0_bearing_deg - magvar_deg;
SG_NORMALIZE_RANGE(wp0_mag_bearing_deg, 0.0, 360.0);
_wp0_mag_bearing_node->setDoubleValue(wp0_mag_bearing_deg);
wp0_bearing_error_deg = track1_deg - wp0_bearing_deg;
SG_NORMALIZE_RANGE(wp0_bearing_error_deg, -180.0, 180.0);
_true_wp0_bearing_error_node->setDoubleValue(wp0_bearing_error_deg);
// Estimate time to waypoint 0.
// The estimation does not take track into consideration,
// so if you are going away from the waypoint the TTW will
// increase. Makes most sense when travelling directly towards
// the waypoint.
if (speed_kt > 0.0 && wp0_distance > 0.0) {
wp0_TTW = (wp0_distance * SG_METER_TO_NM) / (speed_kt / 3600);
}
else {
wp0_TTW = 0.0;
}
unsigned int wp0_TTW_seconds = (int) (wp0_TTW + 0.5);
if (wp0_TTW_seconds < 356400) { // That's 99 hours
unsigned int wp0_TTW_minutes = 0;
unsigned int wp0_TTW_hours = 0;
char wp0_TTW_str[9];
while (wp0_TTW_seconds >= 3600) {
wp0_TTW_seconds -= 3600;
wp0_TTW_hours++;
}
while (wp0_TTW_seconds >= 60) {
wp0_TTW_seconds -= 60;
wp0_TTW_minutes++;
}
snprintf(wp0_TTW_str, 9, "%02d:%02d:%02d",
wp0_TTW_hours, wp0_TTW_minutes, wp0_TTW_seconds);
_wp0_ttw_node->setStringValue(wp0_TTW_str);
}
else
_wp0_ttw_node->setStringValue("--:--:--");
// Course deviation is the diffenrence between the bearing
// and the course.
wp0_course_deviation_deg = wp0_bearing_deg -
wp0_course_deg;
SG_NORMALIZE_RANGE(wp0_course_deviation_deg, -180.0, 180.0);
// If the course deviation is less than 90 degrees to either side,
// our desired course is towards the waypoint.
// It does not matter if we are actually moving
// towards or from the waypoint.
if (fabs(wp0_course_deviation_deg) < 90.0) {
_wp0_to_flag_node->setBoolValue(true); }
// If it's more than 90 degrees the desired
// course is from the waypoint.
else if (fabs(wp0_course_deviation_deg) > 90.0) {
_wp0_to_flag_node->setBoolValue(false);
// When the course is away from the waypoint,
// it makes sense to change the sign of the deviation.
wp0_course_deviation_deg *= -1.0;
SG_NORMALIZE_RANGE(wp0_course_deviation_deg, -90.0, 90.0);
}
_wp0_course_deviation_node->setDoubleValue(wp0_course_deviation_deg);
// Cross track error.
wp0_course_error_m = sin(wp0_course_deviation_deg * SG_PI / 180.0)
* (wp0_distance);
_wp0_course_error_nm_node->setDoubleValue(wp0_course_error_m
* SG_METER_TO_NM);
// Find the bearing and distance to waypoint 1.
SGWayPoint wp1(wp1_longitude_deg, wp1_latitude_deg, wp1_altitude_m);
wp1.CourseAndDistance(longitude_deg, latitude_deg, altitude_m,
&wp1_bearing_deg, &wp1_distance);
_wp1_distance_node->setDoubleValue(wp1_distance * SG_METER_TO_NM);
_wp1_bearing_node->setDoubleValue(wp1_bearing_deg);
double wp1_mag_bearing_deg = wp1_bearing_deg - magvar_deg;
SG_NORMALIZE_RANGE(wp1_mag_bearing_deg, 0.0, 360.0);
_wp1_mag_bearing_node->setDoubleValue(wp1_mag_bearing_deg);
wp1_bearing_error_deg = track1_deg - wp1_bearing_deg;
SG_NORMALIZE_RANGE(wp1_bearing_error_deg, -180.0, 180.0);
_true_wp1_bearing_error_node->setDoubleValue(wp1_bearing_error_deg);
// Estimate time to waypoint 1.
// The estimation does not take track into consideration,
// so if you are going away from the waypoint the TTW will
// increase. Makes most sense when travelling directly towards
// the waypoint.
if (speed_kt > 0.0 && wp1_distance > 0.0) {
wp1_TTW = (wp1_distance * SG_METER_TO_NM) / (speed_kt / 3600);
}
else {
wp1_TTW = 0.0;
}
unsigned int wp1_TTW_seconds = (int) (wp1_TTW + 0.5);
if (wp1_TTW_seconds < 356400) { // That's 99 hours
unsigned int wp1_TTW_minutes = 0;
unsigned int wp1_TTW_hours = 0;
char wp1_TTW_str[9];
while (wp1_TTW_seconds >= 3600) {
wp1_TTW_seconds -= 3600;
wp1_TTW_hours++;
}
while (wp1_TTW_seconds >= 60) {
wp1_TTW_seconds -= 60;
wp1_TTW_minutes++;
}
snprintf(wp1_TTW_str, 9, "%02d:%02d:%02d",
wp1_TTW_hours, wp1_TTW_minutes, wp1_TTW_seconds);
_wp1_ttw_node->setStringValue(wp1_TTW_str);
}
else
_wp1_ttw_node->setStringValue("--:--:--");
// Course deviation is the diffenrence between the bearing
// and the course.
wp1_course_deviation_deg = wp1_bearing_deg - wp1_course_deg;
SG_NORMALIZE_RANGE(wp1_course_deviation_deg, -180.0, 180.0);
// If the course deviation is less than 90 degrees to either side,
// our desired course is towards the waypoint.
// It does not matter if we are actually moving
// towards or from the waypoint.
if (fabs(wp1_course_deviation_deg) < 90.0) {
_wp1_to_flag_node->setBoolValue(true); }
// If it's more than 90 degrees the desired
// course is from the waypoint.
else if (fabs(wp1_course_deviation_deg) > 90.0) {
_wp1_to_flag_node->setBoolValue(false);
// When the course is away from the waypoint,
// it makes sense to change the sign of the deviation.
wp1_course_deviation_deg *= -1.0;
SG_NORMALIZE_RANGE(wp1_course_deviation_deg, -90.0, 90.0);
}
_wp1_course_deviation_node->setDoubleValue(wp1_course_deviation_deg);
// Cross track error.
wp1_course_error_m = sin(wp1_course_deviation_deg * SG_PI / 180.0)
* (wp1_distance);
_wp1_course_error_nm_node->setDoubleValue(wp1_course_error_m
* SG_METER_TO_NM);
// Leg course deviation is the diffenrence between the bearing
// and the course.
double course_deviation_deg = wp1_bearing_deg - _course_deg;
SG_NORMALIZE_RANGE(course_deviation_deg, -180.0, 180.0);
// If the course deviation is less than 90 degrees to either side,
// our desired course is towards the waypoint.
// It does not matter if we are actually moving
// towards or from the waypoint.
if (fabs(course_deviation_deg) < 90.0) {
_leg_to_flag_node->setBoolValue(true); }
// If it's more than 90 degrees the desired
// course is from the waypoint.
else if (fabs(course_deviation_deg) > 90.0) {
_leg_to_flag_node->setBoolValue(false);
// When the course is away from the waypoint,
// it makes sense to change the sign of the deviation.
course_deviation_deg *= -1.0;
SG_NORMALIZE_RANGE(course_deviation_deg, -90.0, 90.0);
}
_leg_course_deviation_node->setDoubleValue(course_deviation_deg);
// Cross track error.
double course_error_m = sin(course_deviation_deg * SG_PI / 180.0)
* (_distance_m);
_leg_course_error_nm_node->setDoubleValue(course_error_m * SG_METER_TO_NM);
// Altitude deviation
double desired_altitude_m = wp1_altitude_m
+ wp1_distance * _alt_dist_ratio;
double altitude_deviation_m = altitude_m - desired_altitude_m;
_alt_deviation_node->setDoubleValue(altitude_deviation_m * SG_METER_TO_FEET);
// Tracking bug.
double tracking_bug = _tracking_bug_node->getDoubleValue();
double true_bug_error = tracking_bug - track1_deg;
double magnetic_bug_error = tracking_bug - mag_track_bearing;
// Get the errors into the (-180,180) range.
SG_NORMALIZE_RANGE(true_bug_error, -180.0, 180.0);
SG_NORMALIZE_RANGE(magnetic_bug_error, -180.0, 180.0);
_true_bug_error_node->setDoubleValue(true_bug_error);
_magnetic_bug_error_node->setDoubleValue(magnetic_bug_error);
// Add WP 1 to the route.
if ( addWp->getBoolValue() )
{
addWp->setBoolValue(false);
SGWayPoint tempWp( _wp1_longitude_node->getDoubleValue(),
_wp1_latitude_node->getDoubleValue(),
_wp1_altitude_node->getDoubleValue(),
SGWayPoint::WGS84,
_wp1_ID_node->getStringValue(),
_wp1_name_node->getStringValue() );
route->add_waypoint(tempWp);
SGPropertyNode *wp =
_route->getChild("Waypoint", route->size()-1, true);
SGPropertyNode *id = wp->getChild("ID", 0, true);
SGPropertyNode *name = wp->getChild("Name", 0, true);
SGPropertyNode *lat = wp->getChild("Latitude", 0, true);
SGPropertyNode *lon = wp->getChild("Longitude", 0, true);
SGPropertyNode *alt = wp->getChild("Altitude", 0, true);
id->setStringValue( tempWp.get_id().c_str() );
name->setStringValue( tempWp.get_name().c_str() );
lat->setDoubleValue( tempWp.get_target_lat() );
lon->setDoubleValue( tempWp.get_target_lon() );
alt->setDoubleValue( tempWp.get_target_alt() );
}
if ( popWp->getBoolValue() )
{
popWp->setBoolValue(false);
route->delete_first();
_route->removeChild("Waypoint", 0, false);
}
} else {
_true_track_node->setDoubleValue(0.0);
_magnetic_track_node->setDoubleValue(0.0);
_speed_node->setDoubleValue(0.0);
}
_last_valid = true;
_last_longitude_deg = longitude_deg;
_last_latitude_deg = latitude_deg;
_last_altitude_m = altitude_m;
}
// end of gps.cxx
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