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flightgear/src/ATC/approach.cxx

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// FGApproach - a class to provide approach control at larger airports.
//
// Written by Alexander Kappes, started March 2002.
//
// Copyright (C) 2002 Alexander Kappes
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of the
// License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
#include "approach.hxx"
#include "ATCdisplay.hxx"
#include <Airports/runways.hxx>
#include <simgear/misc/sg_path.hxx>
#include <WeatherCM/FGLocalWeatherDatabase.h>
//Constructor
FGApproach::FGApproach(){
comm1_node = fgGetNode("/radios/comm[0]/frequencies/selected-mhz", true);
comm2_node = fgGetNode("/radios/comm[1]/frequencies/selected-mhz", true);
num_planes = 0;
lon_node = fgGetNode("/position/longitude-deg", true);
lat_node = fgGetNode("/position/latitude-deg", true);
elev_node = fgGetNode("/position/altitude-ft", true);
first = true;
active_runway = "";
for ( int i=0; i<max_planes; i++) {
planes[i].contact = 0;
planes[i].wpn = 0;
planes[i].dnwp = -999.;
planes[i].on_crs = true;
}
}
//Destructor
FGApproach::~FGApproach(){
}
void FGApproach::Init() {
display = false;
}
// ============================================================================
// the main update function
// ============================================================================
void FGApproach::Update() {
int wpn;
double course, d;
update_plane_dat();
if ( active_runway == "" ) get_active_runway();
for ( int i=0; i<num_planes; i++ ) {
if ( planes[i].contact == 0) {
double comm1_freq = comm1_node->getDoubleValue();
if ( (int)(comm1_freq*100.0 + 0.5) == freq ) planes[i].contact = 1;
}
else if ( planes[i].contact == 1 ) {
if ( planes[i].wpn == 0 ) { // calculate initial waypoints
wpn = planes[i].wpn;
// airport
planes[i].wpts[wpn][0] = active_rw_hdg;
planes[i].wpts[wpn][1] = 0.0;
planes[i].wpts[wpn][2] = elev;
planes[i].wpts[wpn][4] = 0.0;
planes[i].wpts[wpn][5] = 0.0;
wpn += 1;
planes[i].wpts[wpn][0] = active_rw_hdg + 180.0;
if ( planes[i].wpts[wpn][0] > 360.0 ) planes[i].wpts[wpn][0] -= 360.0;
planes[i].wpts[wpn][1] = 5;
planes[i].wpts[wpn][2] = elev + 1000.0;
calc_hd_course_dist(planes[i].wpts[wpn][0], planes[i].wpts[wpn][1],
planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1],
&course, &d);
planes[i].wpts[wpn][4] = course;
planes[i].wpts[wpn][5] = d;
wpn += 1;
planes[i].wpts[wpn][0] = planes[i].brg;
planes[i].wpts[wpn][1] = planes[i].dist;
planes[i].wpts[wpn][2] = planes[i].alt;
calc_hd_course_dist(planes[i].wpts[wpn][0], planes[i].wpts[wpn][1],
planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1],
&course, &d);
planes[i].wpts[wpn][4] = course;
planes[i].wpts[wpn][5] = d;
wpn += 1;
planes[i].wpn = wpn;
planes[i].ahdg = planes[i].wpts[wpn-1][4];
cout << endl;
cout << "Contact " << planes[i].wpn << endl;
cout << "Turn to heading = " << (int)(planes[i].ahdg) << endl;
cout << endl;
planes[i].on_crs = true;
}
// reached waypoint?
if ( fabs(planes[i].dnc) < 0.3 && planes[i].dnwp < 1.0 ) {
planes[i].wpn -= 1;
wpn = planes[i].wpn-1;
planes[i].ahdg = planes[i].wpts[wpn][4];
cout << endl;
cout << "Next waypoint = " << planes[i].wpn << endl;
cout << "New heading = " << planes[i].ahdg << endl;
cout << endl;
planes[i].on_crs = true;
}
// update assigned parameters
wpn = planes[i].wpn-1; // this is the current waypoint
planes[i].dcc = calc_psl_dist(planes[i].brg, planes[i].dist,
planes[i].wpts[wpn][0], planes[i].wpts[wpn][1],
planes[i].wpts[wpn][4]);
planes[i].dnc = calc_psl_dist(planes[i].brg, planes[i].dist,
planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1],
planes[i].wpts[wpn-1][4]);
calc_hd_course_dist(planes[i].brg, planes[i].dist,
planes[i].wpts[wpn-1][0], planes[i].wpts[wpn-1][1],
&course, &d);
planes[i].dnwp = d;
//cout << planes[i].brg << " " << planes[i].dist << " " << planes[i].wpts[wpn+1][0]
//<< " " << planes[i].wpts[wpn+1][1] << " " << planes[i].wpts[wpn+1][4]
//cout << " distance to current course = " << planes[i].dcc << endl;
// come off course ?
if ( fabs(planes[i].dcc) > 0.5 && planes[i].on_crs) {
wpn = wpn-1;
if ( planes[i].wpts[wpn][4] < 0) {
planes[i].ahdg += 30.0;
}
else {
planes[i].ahdg -= 30.0;
}
planes[i].on_crs = false;
cout << endl;
cout << "Your are " << planes[i].dcc << " miles off the asigned course: " << endl;
cout << "New heading = " << (int)(planes[i].ahdg) << endl;
cout << endl;
}
else if ( fabs(planes[i].dcc) < 0.1 && !planes[i].on_crs) {
planes[i].ahdg = fabs(planes[i].wpts[wpn][4]);
planes[i].on_crs = true;
cout << endl;
cout << "New heading = " << (int)(planes[i].ahdg) << endl;
cout << endl;
}
// In range of tower?
if ( planes[i].wpn == 2 && planes[i].dnwp < 3. ) {
cout << endl;
cout << "Contact Tower";
cout << endl;
planes[i].contact = 2;
}
}
}
}
// ============================================================================
// get active runway
// ============================================================================
void FGApproach::get_active_runway() {
sgVec3 position = { lat, lon, elev };
#ifndef FG_NEW_ENVIRONMENT
FGPhysicalProperty stationweather = WeatherDatabase->get(position);
#endif
SGPath path( globals->get_fg_root() );
path.append( "Airports" );
path.append( "runways.mk4" );
FGRunways runways( path.c_str() );
//Set the heading to into the wind
#ifndef FG_NEW_ENVIRONMENT
double wind_x = stationweather.Wind[0];
double wind_y = stationweather.Wind[1];
#else
double wind_x = 0;
double wind_y = 0; // FIXME
#endif
double speed = sqrt( wind_x*wind_x + wind_y*wind_y ) * SG_METER_TO_NM / (60.0*60.0);
double hdg;
//If no wind use 270degrees
if(speed == 0) {
hdg = 270;
} else {
// //normalize the wind to get the direction
//wind_x /= speed; wind_y /= speed;
hdg = - atan2 ( wind_x, wind_y ) * SG_RADIANS_TO_DEGREES ;
if (hdg < 0.0)
hdg += 360.0;
}
FGRunway runway;
if ( runways.search( ident, int(hdg), &runway) ) {
active_runway = runway.rwy_no;
active_rw_hdg = runway.heading;
//cout << "Active runway is: " << active_runway << " heading = "
// << active_rw_hdg << endl;
}
else cout << "FGRunways search failed" << endl;
}
// ========================================================================
// update infos about plane
// ========================================================================
void FGApproach::update_plane_dat() {
//cout << "Update Approach " << ident << " " << num_planes << " registered" << endl;
// update plane positions
for (int i=0; i<num_planes; i++) {
planes[i].lon = lon_node->getDoubleValue();
planes[i].lat = lat_node->getDoubleValue();
planes[i].alt = elev_node->getDoubleValue();
// Point3D aircraft = sgGeodToCart( Point3D(planes[i].lon*SGD_DEGREES_TO_RADIANS,
// planes[i].lat*SGD_DEGREES_TO_RADIANS,
// planes[i].alt*SG_FEET_TO_METER) );
double course, distance;
calc_gc_course_dist(Point3D(lon*SGD_DEGREES_TO_RADIANS, lat*SGD_DEGREES_TO_RADIANS, 0.0),
Point3D(planes[i].lon*SGD_DEGREES_TO_RADIANS,planes[i].lat*SGD_DEGREES_TO_RADIANS, 0.0 ),
&course, &distance);
planes[i].dist = distance/SG_NM_TO_METER;
planes[i].brg = 360.0-course*SGD_RADIANS_TO_DEGREES;
//cout << "Plane Id: " << planes[i].ident << " Distance to " << ident
//<< " is " << planes[i].dist << " m" << endl;
//if (first) {
//transmission = ident;
//globals->get_ATC_display()->RegisterRepeatingMessage(transmission);
//first = false;
//}
}
}
// =======================================================================
// Add plane to Approach list
// =======================================================================
void FGApproach::AddPlane(string pid) {
for ( int i=0; i<num_planes; i++) {
if ( planes[i].ident == pid) {
//cout << "Plane already registered: " << ident << " " << num_planes << endl;
return;
}
}
planes[num_planes].ident = pid;
++num_planes;
//cout << "Plane added to list: " << ident << " " << num_planes << endl;
return;
}
// ========================================================================
// closest distance between a point and a straigt line in 2 dim.
// ========================================================================
double FGApproach::calc_psl_dist(const double &h1, const double &d1,
const double &h2, const double &d2,
const double &h3)
{
double a1 = h1 * SGD_DEGREES_TO_RADIANS;
double a2 = h2 * SGD_DEGREES_TO_RADIANS;
double a3 = h3 * SGD_DEGREES_TO_RADIANS;
double x1 = cos(a1) * d1;
double y1 = sin(a1) * d1;
double x2 = cos(a2) * d2;
double y2 = sin(a2) * d2;
double x3 = cos(a3);
double y3 = sin(a3);
// formula: dis = sqrt( (v1-v2)**2 - ((v1-v2)*v3)**2 ); vi = (xi,yi)
double val1 = (x1-x2)*(x1-x2) + (y1-y2)*(y1-y2);
double val2 = ((x1-x2)*x3 + (y1-y2)*y3) * ((x1-x2)*x3 + (y1-y2)*y3);
double dis = val1 - val2;
// now get sign for offset
//cout << x1 << " " << x2 << " " << y1 << " " << y2 << " "
// << x3 << " " << y3 << " "
// << val1 << " " << val2 << " " << dis << endl;
x3 *= sqrt(val2);
y3 *= sqrt(val2);
if ( x3*(x1-x2) < 0.0 && y3*(y1-y2) < 0.0) {
x3 *= -1.0;
y3 *= -1.0;
}
//cout << x3 << " " << y3 << endl;
double dis1 = x1-x2-x3;
double dis2 = y1-y2-y3;
dis = sqrt(dis);
if (atan2(dis2,dis1) < a3) dis *= -1.0;
//cout << dis1 << " " << dis2 << " " << atan2(dis2,dis1)*SGD_RADIANS_TO_DEGREES << " " << h3
// << " " << sqrt(dis1*dis1 + dis2*dis2) << " " << dis << endl;
//cout << atan2(dis2,dis1)*SGD_RADIANS_TO_DEGREES << " " << dis << endl;
return dis;
}
// ========================================================================
// get heading and distance between two points; point1 ---> point2
// ========================================================================
void FGApproach::calc_hd_course_dist(const double &h1, const double &d1,
const double &h2, const double &d2,
double *course, double *dist)
{
double a1 = h1 * SGD_DEGREES_TO_RADIANS;
double a2 = h2 * SGD_DEGREES_TO_RADIANS;
double x1 = cos(a1) * d1;
double y1 = sin(a1) * d1;
double x2 = cos(a2) * d2;
double y2 = sin(a2) * d2;
*dist = sqrt( (y2-y1)*(y2-y1) + (x2-x1)*(x2-x1) );
*course = atan2( (y2-y1), (x2-x1) ) * SGD_RADIANS_TO_DEGREES;
if ( *course < 0 ) *course = *course+360;
//cout << x1 << " " << y1 << " " << x2 << " " << y2 << " " << *dist << " " << *course << endl;
}
int FGApproach::RemovePlane() {
// first check if anything has to be done
int i;
bool rmplane = false;
for (i=0; i<num_planes; i++) {
if (planes[i].dist > range*SG_NM_TO_METER) {
rmplane = true;
break;
}
}
if (!rmplane) return num_planes;
// now make a copy of the plane list
PlaneApp tmp[max_planes];
for (i=0; i<num_planes; i++) {
tmp[i] = planes[i];
}
int np = 0;
// now check which planes are still in range
for (i=0; i<num_planes; i++) {
if (tmp[i].dist <= range*SG_NM_TO_METER) {
planes[np] = tmp[i];
np += 1;
}
}
num_planes = np;
return num_planes;
}
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