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flightgear/src/Instrumentation/tacan.cxx
mfranz 3b5fed01ca Vivian MEAZZA: 
"Bugfix. Restore earlier bugfix to ensure tacan works when there is no
aircraft carrier in the environment"
2007-04-26 06:49:54 +00:00

533 lines
20 KiB
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// tacan.cxx - Tactical Navigation Beacon.
// Written by Vivian Meazaa, 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/math/sg_geodesy.hxx>
#include <simgear/math/sg_random.h>
#include <Main/fg_props.hxx>
#include <Navaids/navlist.hxx>
#include <vector>
#include "tacan.hxx"
SG_USING_STD(vector);
/**
* Adjust the range.
*
* Start by calculating the radar horizon based on the elevation
* difference, then clamp to the maximum, then add a fudge for
* borderline reception.
*/
static double
adjust_range (double transmitter_elevation_ft, double aircraft_altitude_ft,
double max_range_nm)
{
max_range_nm = 150;
double delta_elevation_ft =
fabs(aircraft_altitude_ft - transmitter_elevation_ft);
double range_nm = 1.23 * sqrt(delta_elevation_ft);
if (range_nm > max_range_nm)
range_nm = max_range_nm;
else if (range_nm < 20.0)
range_nm = 20.0;
double rand = sg_random();
SG_LOG( SG_INSTR, SG_DEBUG, " tacan range " << range_nm << " max range " << max_range_nm);
return range_nm + (range_nm * rand * rand);
}
TACAN::TACAN ( SGPropertyNode *node ) :
_name(node->getStringValue("name", "tacan")),
_num(node->getIntValue("number", 0)),
_new_frequency(false),
_channel("0000"),
_last_distance_nm(0),
_frequency_mhz(-1),
_time_before_search_sec(0),
_mobile_valid(false),
_transmitter_valid(false),
_transmitter_pos(SGGeod::fromDeg(0, 0)),
_transmitter_range_nm(0),
_transmitter_bias(0.0),
_listener_active(0)
{
}
TACAN::~TACAN ()
{
}
void
TACAN::init ()
{
string branch;
branch = "/instrumentation/" + _name;
SGPropertyNode *node = fgGetNode(branch.c_str(), _num, true );
_serviceable_node = node->getChild("serviceable", 0, true);
_ident_node = node->getChild("ident", 0, true);
SGPropertyNode *fnode = node->getChild("frequencies", 0, true);
_frequency_node = fnode->getChild("selected-mhz", 0, true);
_channel_in0_node = fnode->getChild("selected-channel", 0, true);
_channel_in1_node = fnode->getChild("selected-channel", 1, true);
_channel_in2_node = fnode->getChild("selected-channel", 2, true);
_channel_in3_node = fnode->getChild("selected-channel", 3, true);
_channel_in4_node = fnode->getChild("selected-channel", 4, true);
_channel_in0_node->addChangeListener(this);
_channel_in1_node->addChangeListener(this);
_channel_in2_node->addChangeListener(this);
_channel_in3_node->addChangeListener(this);
_channel_in4_node->addChangeListener(this, true);
_in_range_node = node->getChild("in-range", 0, true);
_distance_node = node->getChild("indicated-distance-nm", 0, true);
_speed_node = node->getChild("indicated-ground-speed-kt", 0, true);
_time_node = node->getChild("indicated-time-min", 0, true);
_name_node = node->getChild("name", 0, true);
_bearing_node = node->getChild("indicated-bearing-true-deg", 0, true);
SGPropertyNode *dnode = node->getChild("display", 0, true);
_x_shift_node = dnode->getChild("x-shift", 0, true);
_y_shift_node = dnode->getChild("y-shift", 0, true);
_rotation_node = dnode->getChild("rotation", 0, true);
_channel_node = dnode->getChild("channel", 0, true);
SGPropertyNode *cnode = fgGetNode("/ai/models/carrier", _num, false );
_carrier_name_node = cnode ? cnode->getChild("name", 0, false) : 0;
SGPropertyNode *tnode = fgGetNode("/ai/models/aircraft", _num, false);
_tanker_callsign_node = tnode ? tnode->getChild("callsign", 0, false) : 0;
SGPropertyNode *mnode = fgGetNode("/ai/models/multiplayer", _num, false);
_mp_callsign_node = mnode ? mnode->getChild("callsign", 0, false) : 0;
_longitude_node = fgGetNode("/position/longitude-deg", true);
_latitude_node = fgGetNode("/position/latitude-deg", true);
_altitude_node = fgGetNode("/position/altitude-ft", true);
_heading_node = fgGetNode("/orientation/heading-deg", true);
_yaw_node = fgGetNode("/orientation/side-slip-deg", true);
_electrical_node = fgGetNode("/systems/electrical/outputs/tacan", true);
}
void
TACAN::update (double delta_time_sec)
{
if (!_serviceable_node->getBoolValue() || !_electrical_node->getBoolValue()) {
_last_distance_nm = 0;
_in_range_node->setBoolValue(false);
_distance_node->setDoubleValue(0);
_speed_node->setDoubleValue(0);
_time_node->setDoubleValue(0);
SG_LOG( SG_INSTR, SG_DEBUG, "skip tacan" );
return;
}
// Get the aircraft position
double longitude_deg = _longitude_node->getDoubleValue();
double latitude_deg = _latitude_node->getDoubleValue();
double altitude_m = _altitude_node->getDoubleValue() * SG_FEET_TO_METER;
double longitude_rad = longitude_deg * SGD_DEGREES_TO_RADIANS;
double latitude_rad = latitude_deg * SGD_DEGREES_TO_RADIANS;
// On timeout, scan again
_time_before_search_sec -= delta_time_sec;
if ((_time_before_search_sec < 0 || _new_frequency) && _frequency_mhz >= 0)
search(_frequency_mhz, longitude_rad, latitude_rad, altitude_m);
// Calculate the distance to the transmitter
//calculate the bearing and range of the mobile from the aircraft
double mobile_az2 = 0;
double mobile_bearing = 0;
double mobile_distance = 0;
SG_LOG( SG_INSTR, SG_DEBUG, "mobile_lat " << _mobile_lat);
SG_LOG( SG_INSTR, SG_DEBUG, "mobile_lon " << _mobile_lon);
SG_LOG( SG_INSTR, SG_DEBUG, "mobile_name " << _mobile_name);
SG_LOG( SG_INSTR, SG_DEBUG, "mobile_valid " << _mobile_valid);
geo_inverse_wgs_84(altitude_m,
latitude_deg,
longitude_deg,
_mobile_lat,
_mobile_lon,
&mobile_bearing, &mobile_az2, &mobile_distance);
//calculate the bearing and range of the station from the aircraft
double az2 = 0;
double bearing = 0;
double distance = 0;
SGGeod pos = SGGeod::fromDegM(longitude_deg, latitude_deg, altitude_m);
geo_inverse_wgs_84(pos, _transmitter_pos,
&bearing, &az2, &distance);
//select the nearer
if ( mobile_distance <= distance && _mobile_valid) {
SG_LOG( SG_INSTR, SG_DEBUG, "mobile_distance_m " << mobile_distance);
SG_LOG( SG_INSTR, SG_DEBUG, "distance_m " << distance);
bearing = mobile_bearing;
distance = mobile_distance;
_transmitter_pos.setElevationFt(_mobile_elevation_ft);
_transmitter_range_nm = _mobile_range_nm;
_transmitter_bias = _mobile_bias;
_transmitter_name = _mobile_name;
_name_node->setStringValue(_transmitter_name.c_str());
_transmitter_ident = _mobile_ident;
_ident_node->setStringValue(_transmitter_ident.c_str());
_channel_node->setStringValue(_channel.c_str());
}
//// calculate some values for boresight display
double distance_nm = distance * SG_METER_TO_NM;
//// calculate look left/right to target, without yaw correction
// double horiz_offset = bearing - heading;
//
// if (horiz_offset > 180.0) horiz_offset -= 360.0;
// if (horiz_offset < -180.0) horiz_offset += 360.0;
//// now correct look left/right for yaw
// horiz_offset += yaw;
// use the bearing for a plan position indicator display
double horiz_offset = bearing;
SG_LOG( SG_INSTR, SG_DEBUG, "distance_nm " << distance_nm << " bearing "
<< bearing << " horiz_offset " << horiz_offset);
// calculate values for radar display
double y_shift = distance_nm * cos( horiz_offset * SG_DEGREES_TO_RADIANS);
double x_shift = distance_nm * sin( horiz_offset * SG_DEGREES_TO_RADIANS);
SG_LOG( SG_INSTR, SG_DEBUG, "y_shift " << y_shift << " x_shift " << x_shift);
double rotation = 0;
double range_nm = adjust_range(_transmitter_pos.getElevationFt(),
altitude_m * SG_METER_TO_FEET,
_transmitter_range_nm);
if (distance_nm <= range_nm) {
double speed_kt = (fabs(distance_nm - _last_distance_nm) *
((1 / delta_time_sec) * 3600.0));
_last_distance_nm = distance_nm;
_in_range_node->setBoolValue(true);
double tmp_dist = distance_nm - _transmitter_bias;
if ( tmp_dist < 0.0 ) {
tmp_dist = 0.0;
}
_distance_node->setDoubleValue( tmp_dist );
_speed_node->setDoubleValue(speed_kt);
_time_node->setDoubleValue(distance_nm/speed_kt*60.0);
_bearing_node->setDoubleValue(bearing);
_x_shift_node->setDoubleValue(x_shift);
_y_shift_node->setDoubleValue(y_shift);
_rotation_node->setDoubleValue(rotation);
} else {
_last_distance_nm = 0;
_in_range_node->setBoolValue(false);
_distance_node->setDoubleValue(0);
_speed_node->setDoubleValue(0);
_time_node->setDoubleValue(0);
_bearing_node->setDoubleValue(0);
_x_shift_node->setDoubleValue(0);
_y_shift_node->setDoubleValue(0);
_rotation_node->setDoubleValue(0);
}
// If we can't find a valid station set everything to zero
if (!_transmitter_valid && !_mobile_valid ) {
_in_range_node->setBoolValue(false);
_distance_node->setDoubleValue(0);
_speed_node->setDoubleValue(0);
_time_node->setDoubleValue(0);
_bearing_node->setDoubleValue(0);
_x_shift_node->setDoubleValue(0);
_y_shift_node->setDoubleValue(0);
_rotation_node->setDoubleValue(0);
_transmitter_name = "";
_name_node->setStringValue(_transmitter_name.c_str());
_transmitter_ident = "";
_ident_node->setStringValue(_transmitter_ident.c_str());
_channel_node->setStringValue(_channel.c_str());
return;
}
} // end function update
void
TACAN::search (double frequency_mhz, double longitude_rad,
double latitude_rad, double altitude_m)
{
int number, i;
_mobile_valid = false;
SG_LOG( SG_INSTR, SG_DEBUG, "tacan freq " << frequency_mhz );
// reset search time
_time_before_search_sec = 1.0;
//try any carriers first
FGNavRecord *mobile_tacan
= globals->get_carrierlist()->findStationByFreq( frequency_mhz );
bool freq_valid = (mobile_tacan != NULL);
SG_LOG( SG_INSTR, SG_DEBUG, "mobile freqency valid " << freq_valid );
if ( freq_valid ) {
string str1( mobile_tacan->get_name() );
SGPropertyNode * branch = fgGetNode("ai/models", true);
vector<SGPropertyNode_ptr> carrier = branch->getChildren("carrier");
number = carrier.size();
SG_LOG( SG_INSTR, SG_DEBUG, "carrier " << number );
if ( number > 0 ) { // don't do this if there are no carriers
for ( i = 0; i < number; ++i ) {
string str2 ( carrier[i]->getStringValue("name", ""));
SG_LOG( SG_INSTR, SG_DEBUG, "carrier name " << str2 );
SG_LOG( SG_INSTR, SG_DEBUG, "strings 1 " << str1 << " 2 " << str2 );
string::size_type loc1= str1.find( str2, 0 );
if ( loc1 != string::npos && str2 != "" ) {
SG_LOG( SG_INSTR, SG_DEBUG, " string found" );
_mobile_lat = carrier[i]->getDoubleValue("position/latitude-deg");
_mobile_lon = carrier[i]->getDoubleValue("position/longitude-deg");
_mobile_elevation_ft = mobile_tacan->get_elev_ft();
_mobile_range_nm = mobile_tacan->get_range();
_mobile_bias = mobile_tacan->get_multiuse();
_mobile_name = mobile_tacan->get_name();
_mobile_ident = mobile_tacan->get_trans_ident();
_mobile_valid = true;
SG_LOG( SG_INSTR, SG_DEBUG, " carrier transmitter valid " << _mobile_valid );
break;
} else {
_mobile_valid = false;
SG_LOG( SG_INSTR, SG_DEBUG, " carrier transmitter invalid " << _mobile_valid );
}
}
}
SG_LOG( SG_INSTR, SG_DEBUG, "name " << _mobile_name);
SG_LOG( SG_INSTR, SG_DEBUG, "lat " << _mobile_lat << "lon " << _mobile_lon);
SG_LOG( SG_INSTR, SG_DEBUG, "elev " << _mobile_elevation_ft);
//try any AI tankers second
if ( !_mobile_valid) {
SG_LOG( SG_INSTR, SG_DEBUG, "tanker transmitter valid start " << _mobile_valid );
SGPropertyNode * branch = fgGetNode("ai/models", true);
vector<SGPropertyNode_ptr> tanker = branch->getChildren("aircraft");
number = tanker.size();
SG_LOG( SG_INSTR, SG_DEBUG, "tanker number " << number );
if ( number > 0 ) { // don't do this if there are no AI aircraft
for ( i = 0; i < number; ++i ) {
string str4 ( tanker[i]->getStringValue("callsign", ""));
SG_LOG( SG_INSTR, SG_DEBUG, "tanker callsign " << str4 );
SG_LOG( SG_INSTR, SG_DEBUG, "strings 1 " << str1 << " 4 " << str4 );
string::size_type loc1= str1.find( str4, 0 );
if ( loc1 != string::npos && str4 != "" ) {
SG_LOG( SG_INSTR, SG_DEBUG, " string found" );
_mobile_lat = tanker[i]->getDoubleValue("position/latitude-deg");
_mobile_lon = tanker[i]->getDoubleValue("position/longitude-deg");
_mobile_elevation_ft = tanker[i]->getDoubleValue("position/altitude-ft");
_mobile_range_nm = mobile_tacan->get_range();
_mobile_bias = mobile_tacan->get_multiuse();
_mobile_name = mobile_tacan->get_name();
_mobile_ident = mobile_tacan->get_trans_ident();
_mobile_valid = true;
SG_LOG( SG_INSTR, SG_DEBUG, " tanker transmitter valid " << _mobile_valid );
break;
} else {
_mobile_valid = false;
SG_LOG( SG_INSTR, SG_DEBUG, " tanker transmitter invalid " << _mobile_valid );
}
}
}
SG_LOG( SG_INSTR, SG_DEBUG, "tanker name " << _mobile_name);
SG_LOG( SG_INSTR, SG_DEBUG, "lat " << _mobile_lat << "lon " << _mobile_lon);
SG_LOG( SG_INSTR, SG_DEBUG, "elev " << _mobile_elevation_ft);
SG_LOG( SG_INSTR, SG_DEBUG, "range " << _mobile_range_nm);
}
//try any mp tankers third, if we haven't found the tanker in the ai aircraft
if ( !_mobile_valid ) {
SG_LOG( SG_INSTR, SG_DEBUG, " mp tanker transmitter valid start " << _mobile_valid );
SGPropertyNode * branch = fgGetNode("ai/models", true);
vector<SGPropertyNode_ptr> mp_tanker = branch->getChildren("multiplayer");
number = mp_tanker.size();
SG_LOG( SG_INSTR, SG_DEBUG, " mp tanker number " << number );
if ( number > 0 ) { // don't do this if there are no MP aircraft
for ( i = 0; i < number; ++i ) {
string str6 ( mp_tanker[i]->getStringValue("callsign", ""));
SG_LOG( SG_INSTR, SG_DEBUG, "mp tanker callsign " << str6 );
SG_LOG( SG_INSTR, SG_DEBUG, "strings 1 " << str1 << " 5 " << str6 );
string::size_type loc1= str1.find( str6, 0 );
if ( loc1 != string::npos && str6 != "" ) {
SG_LOG( SG_INSTR, SG_DEBUG, " string found" );
_mobile_lat = mp_tanker[i]->getDoubleValue("position/latitude-deg");
_mobile_lon = mp_tanker[i]->getDoubleValue("position/longitude-deg");
_mobile_elevation_ft = mp_tanker[i]->getDoubleValue("position/altitude-ft");
_mobile_range_nm = mobile_tacan->get_range();
_mobile_bias = mobile_tacan->get_multiuse();
_mobile_name = mobile_tacan->get_name();
_mobile_ident = mobile_tacan->get_trans_ident();
_mobile_valid = true;
SG_LOG( SG_INSTR, SG_DEBUG, " mp tanker transmitter valid " << _mobile_valid );
SG_LOG( SG_INSTR, SG_DEBUG, " mp tanker name " << _mobile_name);
SG_LOG( SG_INSTR, SG_DEBUG, " mp lat " << _mobile_lat << "lon " << _mobile_lon);
SG_LOG( SG_INSTR, SG_DEBUG, " mp elev " << _mobile_elevation_ft);
SG_LOG( SG_INSTR, SG_DEBUG, " mp range " << _mobile_range_nm);
break;
} else {
_mobile_valid = false;
SG_LOG( SG_INSTR, SG_DEBUG, " mp tanker transmitter invalid " << _mobile_valid );
}
}
}
}
} else {
_mobile_valid = false;
SG_LOG( SG_INSTR, SG_DEBUG, " mobile transmitter invalid " << _mobile_valid );
}
// try the TACAN/VORTAC list next
FGNavRecord *tacan
= globals->get_tacanlist()->findByFreq( frequency_mhz, longitude_rad,
latitude_rad, altitude_m);
_transmitter_valid = (tacan != NULL);
if ( _transmitter_valid ) {
SG_LOG( SG_INSTR, SG_DEBUG, "transmitter valid " << _transmitter_valid );
_transmitter_pos = tacan->get_pos();
_transmitter_range_nm = tacan->get_range();
_transmitter_bias = tacan->get_multiuse();
_transmitter_name = tacan->get_name();
_name_node->setStringValue(_transmitter_name.c_str());
_transmitter_ident = tacan->get_trans_ident();
_ident_node->setStringValue(_transmitter_ident.c_str());
SG_LOG( SG_INSTR, SG_DEBUG, "name " << _transmitter_name);
SG_LOG( SG_INSTR, SG_DEBUG, _transmitter_pos);
} else {
SG_LOG( SG_INSTR, SG_DEBUG, "transmitter invalid " << _transmitter_valid );
}
}
double
TACAN::searchChannel (const string& channel)
{
double frequency_khz = 0;
FGTACANRecord *freq
= globals->get_channellist()->findByChannel( channel );
bool _freq_valid = (freq != NULL);
SG_LOG( SG_INSTR, SG_DEBUG, "freq valid " << _freq_valid );
if ( _freq_valid ) {
frequency_khz = freq->get_freq();
SG_LOG( SG_INSTR, SG_DEBUG, "freq output " << frequency_khz );
//check sanity
if (frequency_khz >= 9620 && frequency_khz <= 121300)
return frequency_khz/100;
}
return frequency_khz = 0;
} // end TACAN::searchChannel
/*
* Listener callback. Maintains channel input properties,
* searches new channel frequency, updates _channel and
* _frequency and sets boolean _new_frequency appropriately.
*/
void
TACAN::valueChanged(SGPropertyNode *prop)
{
if (_listener_active)
return;
_listener_active++;
int index = prop->getIndex();
string channel = _channel;
if (index) { // channel digit or X/Y input
int c;
if (isdigit(c = _channel_in1_node->getStringValue()[0]))
channel[0] = c;
if (isdigit(c = _channel_in2_node->getStringValue()[0]))
channel[1] = c;
if (isdigit(c = _channel_in3_node->getStringValue()[0]))
channel[2] = c;
c = _channel_in4_node->getStringValue()[0];
if (c == 'X' || c == 'Y')
channel[3] = c;
} else { // channel number input
unsigned int f = prop->getIntValue();
if (f >= 1 && f <= 126) {
channel[0] = '0' + (f / 100) % 10;
channel[1] = '0' + (f / 10) % 10;
channel[2] = '0' + f % 10;
}
}
if (channel != _channel) {
SG_LOG(SG_INSTR, SG_DEBUG, "new channel " << channel);
// write back result
_channel_in0_node->setIntValue((channel[0] - '0') * 100
+ (channel[1] - '0') * 10 + (channel[2] - '0'));
char s[2] = "0";
s[0] = channel[0], _channel_in1_node->setStringValue(s);
s[0] = channel[1], _channel_in2_node->setStringValue(s);
s[0] = channel[2], _channel_in3_node->setStringValue(s);
s[0] = channel[3], _channel_in4_node->setStringValue(s);
// search channel frequency
double freq = searchChannel(channel);
if (freq != _frequency_mhz) {
SG_LOG(SG_INSTR, SG_DEBUG, "new frequency " << freq);
_frequency_node->setDoubleValue(freq);
_frequency_mhz = freq;
_new_frequency = true;
}
_channel = channel;
_time_before_search_sec = 0;
}
_listener_active--;
}
// end of TACAN.cxx
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