Vivian Meazza: AI escorts

src/AIModel/AIBase.hxx

@@ -45,7 +45,7 @@ class FGAIBase : public osg::Referenced {
 public:
     enum object_type { otNull = 0, otAircraft, otShip, otCarrier, otBallistic,
                        otRocket, otStorm, otThermal, otStatic, otWingman, otGroundVehicle,
-                       otMultiplayer,
+                       otEscort, otMultiplayer,
                        MAX_OBJECTS };	// Needs to be last!!!
 
     FGAIBase(object_type ot);

src/AIModel/AICarrier.cxx

@@ -127,8 +127,8 @@ void FGAICarrier::update(double dt) {
     FGAIShip::update(dt);
 
     //automatic turn into wind with a target wind of 25 kts otd
-    //SG_LOG(SG_GENERAL, SG_ALERT, "AICarrier: MPControl " << MPControl );
+    //SG_LOG(SG_GENERAL, SG_ALERT, "AICarrier: MPControl " << MPControl << " AIControl " << AIControl);
-    if (!MPControl){
+    if (!MPControl && AIControl){
 
         if(turn_to_launch_hdg){
             TurnToLaunch();
@@ -260,8 +260,8 @@ void FGAICarrier::bind() {
                SGRawValueMethods<SGGeod,double>(pos, &SGGeod::getLongitudeDeg));
     props->tie("controls/mp-control",
                 SGRawValuePointer<bool>(&MPControl));
-    props->tie("velocities/speed-kts",
+    props->tie("controls/ai-control",
-                SGRawValuePointer<double>(&speed));
+                SGRawValuePointer<bool>(&AIControl));
     props->tie("environment/surface-wind-speed-true-kts",
                 SGRawValuePointer<double>(&wind_speed_kts));
     props->tie("environment/surface-wind-from-true-degs",
@@ -317,7 +317,6 @@ void FGAICarrier::unbind() {
     props->untie("controls/flols/distance-m");
     props->untie("controls/flols/angle-degs");
     props->untie("controls/turn-to-launch-hdg");
-    props->untie("velocities/speed-kts");
     props->untie("environment/wind-speed-true-kts");
     props->untie("environment/wind-from-true-degs");
     props->untie("environment/rel-wind-from-degs");
@@ -333,6 +332,7 @@ void FGAICarrier::unbind() {
     props->untie("controls/constants/jbd/trans-time-s");
     props->untie("controls/jbd-time-constant");
     props->untie("controls/mp-control");
+    props->untie("controls/ai-control");
     props->untie("controls/turn-to-recovery-hdg");
     props->untie("controls/turn-to-base-course");
 }

src/AIModel/AICarrier.hxx

@@ -123,7 +123,7 @@ private:
     bool turn_to_base_course;
     bool returning;      // set if the carrier is returning to an operating box
     bool InToWind();     // set if the carrier is in to wind
-    bool MPControl;
+    bool MPControl, AIControl;
 
 
     SGPropertyNode_ptr _longitude_node;

src/AIModel/AIEscort.cxx

@@ -0,0 +1,441 @@
+// FGAIEscort - FGAIShip-derived class creates an AI Ground Vehicle
+// by adding a ground following utility
+//
+// Written by Vivian Meazza, started August 2009.
+// - vivian.meazza at lineone.net
+//
+// 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+
+#ifdef HAVE_CONFIG_H
+#  include <config.h>
+#endif
+
+#include <algorithm>
+#include <string>
+#include <vector>
+
+#include <simgear/sg_inlines.h>
+#include <simgear/math/SGMath.hxx>
+#include <simgear/math/sg_geodesy.hxx>
+
+#include <math.h>
+#include <Main/util.hxx>
+#include <Main/viewer.hxx>
+
+#include <Scenery/scenery.hxx>
+#include <Scenery/tilemgr.hxx>
+
+#include "AIEscort.hxx"
+
+FGAIEscort::FGAIEscort() :
+FGAIShip(otEscort),
+
+_selected_ac(0),
+_relbrg (0),
+_stn_truebrg(0),
+_parent_speed(0),
+_stn_limit(0),
+_stn_angle_limit(0),
+_stn_speed(0),
+_stn_height(0),
+_max_speed(0),
+_interval(0),
+_MPControl(false),
+_patrol(false),
+_stn_deg_true(false),
+_parent("")
+
+{
+    invisible = false;
+}
+
+FGAIEscort::~FGAIEscort() {}
+
+void FGAIEscort::readFromScenario(SGPropertyNode* scFileNode) {
+    if (!scFileNode)
+        return;
+
+    FGAIShip::readFromScenario(scFileNode);
+
+    setName(scFileNode->getStringValue("name", "Escort"));
+    setSMPath(scFileNode->getStringValue("submodel-path", ""));
+    setStnRange(scFileNode->getDoubleValue("station/range-nm", 1));
+    setStnBrg(scFileNode->getDoubleValue("station/brg-deg", 0.0));
+    setStnLimit(scFileNode->getDoubleValue("station/range-limit-nm", 0.2));
+    setStnAngleLimit(scFileNode->getDoubleValue("station/angle-limit-deg", 15.0));
+    setStnSpeed(scFileNode->getDoubleValue("station/speed-kts", 2.5));
+    setStnPatrol(scFileNode->getBoolValue("station/patrol", false));
+    setStnHtFt(scFileNode->getDoubleValue("station/height-ft", 0.0));
+    setStnDegTrue(scFileNode->getBoolValue("station/deg-true", false));
+    setParentName(scFileNode->getStringValue("station/parent", ""));
+    setMaxSpeed(scFileNode->getDoubleValue("max-speed-kts", 30.0));
+    setUpdateInterval(scFileNode->getDoubleValue("update-interval-sec", 10.0));
+    setCallSign(scFileNode->getStringValue("callsign", ""));
+
+    if(_patrol)
+        sg_srandom_time();
+
+}
+
+void FGAIEscort::bind() {
+    FGAIShip::bind();
+
+    props->tie("station/rel-bearing-deg",
+        SGRawValuePointer<double>(&_stn_relbrg));
+    props->tie("station/true-bearing-deg",
+        SGRawValuePointer<double>(&_stn_truebrg));
+    props->tie("station/range-nm",
+        SGRawValuePointer<double>(&_stn_range));
+    props->tie("station/range-limit-nm",
+        SGRawValuePointer<double>(&_stn_limit));
+    props->tie("station/angle-limit-deg",
+        SGRawValuePointer<double>(&_stn_angle_limit));
+    props->tie("station/speed-kts",
+        SGRawValuePointer<double>(&_stn_speed));
+    props->tie("station/height-ft",
+        SGRawValuePointer<double>(&_stn_height));
+    props->tie("controls/update-interval-sec",
+        SGRawValuePointer<double>(&_interval));
+    props->tie("controls/parent-mp-control",
+        SGRawValuePointer<bool>(&_MPControl));
+    props->tie("station/target-range-nm",
+        SGRawValuePointer<double>(&_tgtrange));
+    props->tie("station/target-brg-deg-t",
+        SGRawValuePointer<double>(&_tgtbrg));
+    props->tie("station/patrol",
+        SGRawValuePointer<bool>(&_patrol));
+}
+
+void FGAIEscort::unbind() {
+    FGAIShip::unbind();
+
+    props->untie("station/rel-bearing-deg");
+    props->untie("station/true-bearing-deg");
+    props->untie("station/range-nm");
+    props->untie("station/range-limit-nm");
+    props->untie("station/angle-limit-deg");
+    props->untie("station/speed-kts");
+    props->untie("station/height-ft");
+    props->untie("controls/update-interval-sec");
+
+}
+
+bool FGAIEscort::init(bool search_in_AI_path) {
+    if (!FGAIShip::init(search_in_AI_path))
+        return false;
+
+    invisible = false;
+    no_roll = false;
+
+    props->setStringValue("controls/parent-name", _parent.c_str());
+    setParent();
+    pos = _tgtpos;
+    speed = _parent_speed;
+    hdg = _parent_hdg;
+
+    return true;
+}
+
+void FGAIEscort::update(double dt) {
+    FGAIShip::update(dt);
+
+    RunEscort(dt);
+}
+
+void FGAIEscort::setStnRange(double r) {
+    _stn_range = r;
+}
+
+void FGAIEscort::setStnBrg(double b) {
+    _stn_brg = b;
+}
+
+void FGAIEscort::setStnLimit(double l) {
+    _stn_limit = l;
+}
+
+void FGAIEscort::setStnAngleLimit(double al) {
+    _stn_angle_limit = al;
+}
+
+void FGAIEscort::setStnSpeed(double s) {
+    _stn_speed = s;
+}
+
+void FGAIEscort::setStnHtFt(double h) {
+    _stn_height = h;
+}
+
+void FGAIEscort::setStnDegTrue(bool t) {
+    _stn_deg_true = t;
+}
+
+void FGAIEscort::setMaxSpeed(double m) {
+    _max_speed = m;
+}
+
+void FGAIEscort::setUpdateInterval(double i) {
+    _interval = i;
+}
+
+void FGAIEscort::setStnPatrol(bool p) {
+    _patrol = p;
+}
+
+void FGAIEscort::setParentName(const string& p) {
+    _parent = p;
+}
+
+bool FGAIEscort::getGroundElev(SGGeod inpos) {
+
+    double height_m ;
+
+    if (globals->get_scenery()->get_elevation_m(SGGeod::fromGeodM(inpos, 3000), height_m, &_material,0)){
+        _ht_agl_ft = inpos.getElevationFt() - height_m * SG_METER_TO_FEET;
+
+        if (_material) {
+            const vector<string>& names = _material->get_names();
+
+            _solid = _material->get_solid();
+
+            if (!names.empty())
+                props->setStringValue("material/name", names[0].c_str());
+            else
+                props->setStringValue("material/name", "");
+
+            //cout << "material " << names[0].c_str()
+            //    << " _elevation_m " << _elevation_m
+            //    << " solid " << _solid
+            //    << " load " << _load_resistance
+            //    << " frictionFactor " << _frictionFactor
+            //    << endl;
+
+        }
+
+        return true;
+    } else {
+        return false;
+    }
+
+}
+
+void FGAIEscort::setParent() {
+
+    const SGPropertyNode *ai = fgGetNode("/ai/models", true);
+
+    for (int i = ai->nChildren() - 1; i >= -1; i--) {
+        const SGPropertyNode *model;
+
+        if (i < 0) { // last iteration: selected model
+            model = _selected_ac;
+        } else {
+            model = ai->getChild(i);
+            string path = ai->getPath();
+            const string name = model->getStringValue("name");
+
+            if (!model->nChildren()){
+                continue;
+            }
+            if (name == _parent) {
+                _selected_ac = model;  // save selected model for last iteration
+                break;
+            }
+
+        }
+        if (!model)
+            continue;
+
+    }// end for loop
+
+    if (_selected_ac != 0){
+        const string name = _selected_ac->getStringValue("name");
+        double lat = _selected_ac->getDoubleValue("position/latitude-deg");
+        double lon = _selected_ac->getDoubleValue("position/longitude-deg");
+        double elevation = _selected_ac->getDoubleValue("position/altitude-ft");
+        _MPControl = _selected_ac->getBoolValue("controls/mp-control");
+
+        _selectedpos.setLatitudeDeg(lat);
+        _selectedpos.setLongitudeDeg(lon);
+        _selectedpos.setElevationFt(elevation);
+
+        _parent_speed    = _selected_ac->getDoubleValue("velocities/speed-kts");
+        _parent_hdg      = _selected_ac->getDoubleValue("orientation/true-heading-deg");
+
+        if(!_stn_deg_true){
+            _stn_truebrg = calcTrueBearingDeg(_stn_brg, _parent_hdg);
+            _stn_relbrg = _stn_brg;
+            //cout << _name <<" set rel"<<endl;
+        } else {
+            _stn_truebrg = _stn_brg;
+            _stn_relbrg = calcRelBearingDeg(_stn_brg, _parent_hdg); 
+            //cout << _name << " set true"<<endl;
+        }
+
+        double course2;
+
+        SGGeodesy::direct( _selectedpos, _stn_truebrg, _stn_range * SG_NM_TO_METER,
+            _tgtpos, course2);
+
+        _tgtpos.setElevationFt(_stn_height);
+
+        calcRangeBearing(pos.getLatitudeDeg(), pos.getLongitudeDeg(),
+            _tgtpos.getLatitudeDeg(), _tgtpos.getLongitudeDeg(), _tgtrange, _tgtbrg);
+
+        _relbrg = calcRelBearingDeg(_tgtbrg, hdg);
+
+    } else {
+        SG_LOG(SG_GENERAL, SG_ALERT, "AIEscort: " << _name
+            << " parent not found: dying ");
+        setDie(true);
+    }
+
+}
+
+void FGAIEscort::calcRangeBearing(double lat, double lon, double lat2, double lon2,
+                                  double &range, double &bearing) const
+{
+    // calculate the bearing and range of the second pos from the first
+    double az2, distance;
+    geo_inverse_wgs_84(lat, lon, lat2, lon2, &bearing, &az2, &distance);
+    range = distance * SG_METER_TO_NM;
+}
+
+double FGAIEscort::calcRelBearingDeg(double bearing, double heading)
+{
+    double angle = bearing - heading;
+    SG_NORMALIZE_RANGE(angle, -180.0, 180.0);
+    return angle;
+}
+
+double FGAIEscort::calcTrueBearingDeg(double bearing, double heading)
+{
+    double angle = bearing + heading;
+    SG_NORMALIZE_RANGE(angle, 0.0, 360.0);
+    return angle;
+}
+
+double FGAIEscort::calcRecipBearingDeg(double bearing)
+{
+    double angle = bearing - 180;
+    SG_NORMALIZE_RANGE(angle, 0.0, 360.0);
+    return angle;
+}
+
+SGVec3d FGAIEscort::getCartHitchPosAt(const SGVec3d& _off) const {
+    double hdg = _selected_ac->getDoubleValue("orientation/true-heading-deg");
+    double pitch = _selected_ac->getDoubleValue("orientation/pitch-deg");
+    double roll = _selected_ac->getDoubleValue("orientation/roll-deg");
+
+    // Transform that one to the horizontal local coordinate system.
+    SGQuatd hlTrans = SGQuatd::fromLonLat(_selectedpos);
+
+    // and postrotate the orientation of the AIModel wrt the horizontal
+    // local frame
+    hlTrans *= SGQuatd::fromYawPitchRollDeg(hdg, pitch, roll);
+
+    // The offset converted to the usual body fixed coordinate system
+    // rotated to the earth fiexed coordinates axis
+    SGVec3d off = hlTrans.backTransform(_off);
+
+    // Add the position offset of the AIModel to gain the earth centered position
+    SGVec3d cartPos = SGVec3d::fromGeod(_selectedpos);
+
+    return cartPos + off;
+}
+
+
+void FGAIEscort::setStationSpeed(){
+
+    double speed = 0;
+    double angle = 0;
+
+    // these are the AI rules for the manoeuvring of escorts
+
+    if (_MPControl && _tgtrange > 4 * _stn_limit){
+        SG_LOG(SG_GENERAL, SG_ALERT, "AIEscort: " << _name
+            << " re-aligning to MP pos");
+        pos = _tgtpos;
+        speed = 0;
+        angle = 0;
+    }else if ((_relbrg < -90 || _relbrg > 90) && _tgtrange > _stn_limit ){
+        angle =_relbrg;
+
+        if(_tgtrange > 4 * _stn_limit)
+            speed = 4 * -_stn_speed;
+        else
+            speed = -_stn_speed;
+
+    }else if ((_relbrg >= -90 || _relbrg <= 90) && _tgtrange > _stn_limit){
+        angle = _relbrg;
+
+        if(_tgtrange > 4 * _stn_limit)
+            speed = 4 * _stn_speed;
+        else
+            speed = _stn_speed;
+
+    } else {
+
+        if(_patrol){
+            angle = 15 * sg_random();
+            speed =  5 * sg_random();
+        } else {
+            angle = 0;
+            speed = 0;
+        }
+
+    }
+
+    double station_speed = _parent_speed + speed;
+
+    SG_CLAMP_RANGE(station_speed, 5.0, _max_speed);
+    SG_CLAMP_RANGE(angle, -_stn_angle_limit, _stn_angle_limit);
+
+    AccelTo(station_speed);
+    TurnTo(_parent_hdg + angle);
+    ClimbTo(_stn_height);
+
+}
+
+void FGAIEscort::RunEscort(double dt){
+
+    _dt_count += dt;
+
+
+
+    ///////////////////////////////////////////////////////////////////////////
+    // Check execution time (currently once every 0.05 sec or 20 fps)
+    // Add a bit of randomization to prevent the execution of all flight plans
+    // in synchrony, which can add significant periodic framerate flutter.
+    // Randomization removed to get better appearance
+    ///////////////////////////////////////////////////////////////////////////
+
+    //cout << "_start_sec " << _start_sec << " time_sec " << time_sec << endl;
+    if (_dt_count < _next_run)
+        return;
+    _next_run = _interval /*+ (0.015 * sg_random())*/;
+
+    if(_parent == ""){
+        return;
+    }
+
+    setParent();
+    setStationSpeed();
+    //getGroundElev(pos);
+
+    _dt_count = 0;
+
+}
+
+// end AIGroundvehicle

src/AIModel/AIEscort.hxx

@@ -0,0 +1,109 @@
+// FGAIGroundVehicle - FGAIShip-derived class creates an AI Ground Vehicle
+// by adding a ground following utility
+//
+// Written by Vivian Meazza, started August 2009.
+// - vivian.meazza at lineone.net
+//
+// 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+
+#ifndef _FG_AIESCORT_HXX
+#define _FG_AIESCORT_HXX
+
+#include <string>
+#include <list>
+
+#include <simgear/compiler.h>
+
+using std::string;
+using std::list;
+
+#include "AIBase.hxx"
+
+#include "AIShip.hxx"
+
+#include "AIManager.hxx"
+#include "AIBase.hxx"
+
+class FGAIEscort : public FGAIShip {
+public:
+    FGAIEscort();
+    virtual ~FGAIEscort();
+
+    virtual void readFromScenario(SGPropertyNode* scFileNode);
+    virtual void bind();
+    virtual void unbind();
+    virtual const char* getTypeString(void) const { return "escort"; }
+
+    bool init(bool search_in_AI_path=false);
+
+private:
+
+    virtual void reinit() { init(); }
+    virtual void update (double dt);
+
+    void setParentName(const string& p);
+    void setParent();
+    void setStnRange(double r);
+    void setStnBrg(double y);
+    void setStationSpeed();
+    void setStnLimit(double l);
+    void setStnAngleLimit(double l);
+    void setStnSpeed(double s);
+    void setStnHtFt(double h);
+    void setStnPatrol(bool p);
+    void setStnDegTrue(bool t);
+
+    void setMaxSpeed(double m);
+    void setUpdateInterval(double i);
+
+    void RunEscort(double dt);
+
+    bool getGroundElev(SGGeod inpos);
+
+    SGVec3d getCartHitchPosAt(const SGVec3d& off) const;
+
+    void calcRangeBearing(double lat, double lon, double lat2, double lon2,
+        double &range, double &bearing) const;
+    double calcRelBearingDeg(double bearing, double heading);
+    double calcTrueBearingDeg(double bearing, double heading);
+    double calcRecipBearingDeg(double bearing);
+
+    SGGeod _selectedpos;
+    SGGeod _tgtpos;
+
+    bool   _solid;           // if true ground is solid for FDMs
+    double _load_resistance; // ground load resistanc N/m^2
+    double _frictionFactor;  // dimensionless modifier for Coefficient of Friction
+    double _tgtrange, _tgtbrg;
+    double _ht_agl_ft;
+    double _relbrg, _truebrg;
+    double _parent_speed, _parent_hdg;
+    double _interval;
+
+    double _stn_relbrg, _stn_truebrg, _stn_brg, _stn_range, _stn_height;
+    double _stn_speed, _stn_angle_limit, _stn_limit;
+
+    double _max_speed;
+
+    const SGMaterial* _material;
+    const SGPropertyNode *_selected_ac;
+
+    bool _MPControl, _patrol, _stn_deg_true;
+
+    string _parent;
+
+};
+
+#endif  // FG_AIGROUNDVEHICLE_HXX

src/AIModel/AIManager.cxx

@@ -39,6 +39,7 @@
 #include "AITanker.hxx"
 #include "AIWingman.hxx"
 #include "AIGroundVehicle.hxx"
+#include "AIEscort.hxx"
 
 FGAIManager::FGAIManager() {
     _dt = 0.0;
@@ -311,6 +312,11 @@ FGAIManager::processScenario( const string &filename ) {
             groundvehicle->readFromScenario(scEntry);
             attach(groundvehicle);
 
+        } else if (type == "escort") {
+            FGAIEscort* escort = new FGAIEscort;
+            escort->readFromScenario(scEntry);
+            attach(escort);
+
         } else if (type == "thunderstorm") {
             FGAIStorm* storm = new FGAIStorm;
             storm->readFromScenario(scEntry);
@@ -395,8 +401,8 @@ const FGAIBase *
 FGAIManager::calcCollision(double alt, double lat, double lon, double fuse_range)
 {
     // we specify tgt extent (ft) according to the AIObject type
-    double tgt_ht[]     = {0,  50, 100, 250, 0, 100, 0, 0,  50, 50,  20,  50};
+    double tgt_ht[]     = {0,  50, 100, 250, 0, 100, 0, 0,  50,  50, 20, 100,  50};
-    double tgt_length[] = {0, 100, 200, 750, 0,  50, 0, 0, 200, 100, 40, 100};
+    double tgt_length[] = {0, 100, 200, 750, 0,  50, 0, 0, 200, 100, 40, 200, 100};
     ai_list_iterator ai_list_itr = ai_list.begin();
     ai_list_iterator end = ai_list.end();
 

src/AIModel/AIShip.cxx

@@ -43,7 +43,7 @@
 
 FGAIShip::FGAIShip(object_type ot) :
 FGAIBase(ot),
-_limit(40),
+_limit(100),
 _elevation_m(0),
 _elevation_ft(0),
 _tow_angle(0),
@@ -200,6 +200,8 @@ void FGAIShip::bind() {
         SGRawValuePointer<double>(&_fixed_turn_radius));
     props->tie("controls/restart",
         SGRawValuePointer<bool>(&_restart));
+    props->tie("velocities/speed-kts",
+                SGRawValuePointer<double>(&speed));
 }
 
 void FGAIShip::unbind() {
@@ -236,6 +238,7 @@ void FGAIShip::unbind() {
     props->untie("controls/fixed-turn-radius-ft");
     props->untie("controls/constants/speed");
     props->untie("controls/restart");
+    props->untie("velocities/speed-kts");
 
 }
 void FGAIShip::update(double dt) {
@@ -309,8 +312,7 @@ void FGAIShip::Run(double dt) {
     }
 
     // do not allow unreasonable speeds
-    if (speed > _limit)
+    SG_CLAMP_RANGE(speed, -_limit * 0.75, _limit);
-        speed = _limit;
 
     // convert speed to degrees per second
     speed_north_deg_sec = cos(hdg / SGD_RADIANS_TO_DEGREES)
@@ -337,7 +339,7 @@ void FGAIShip::Run(double dt) {
 
 
     //we assume that at slow speed ships will manoeuvre using engines/bow thruster
-	if(type == "ship" || type == "carrier"){
+	if(type == "ship" || type == "carrier" || type == "escort"){
 
 		if (fabs(speed)<=5)
 			_sp_turn_radius_ft = _fixed_turn_radius;
@@ -418,7 +420,7 @@ void FGAIShip::Run(double dt) {
     }
 
     // set the _rudder limit by speed
-    if (type == "ship" || type == "carrier"){
+    if (type == "ship" || type == "carrier" || type == "escort"){
 
         if (speed <= 40)
             rudder_limit = (-0.825 * speed) + 35;

src/AIModel/AIShip.hxx

@@ -79,6 +79,7 @@ public:
     double _rudder_constant, _speed_constant, _hdg_constant, _limit ;
     double _elevation_m, _elevation_ft;
     double _missed_range, _tow_angle, _wait_count, _missed_count,_wp_range;
+    double _dt_count, _next_run;
 
     FGAIFlightPlan::waypoint* prev; // the one behind you
     FGAIFlightPlan::waypoint* curr; // the one ahead
@@ -123,8 +124,6 @@ private:
     double _roll_constant, _roll_factor;
     double _sp_turn_radius_ft, _rd_turn_radius_ft, _fixed_turn_radius;
     double _old_range, _range_rate;
-    double _dt_count;
-    double _next_run;
     double _missed_time_sec;
     double _start_sec;
     double _day;

src/AIModel/Makefile.am

@@ -18,6 +18,7 @@ libAIModel_a_SOURCES = submodel.cxx submodel.hxx 	\
 			AITanker.cxx AITanker.hxx \
 			AIWingman.cxx AIWingman.hxx\
 			AIGroundVehicle.cxx AIGroundVehicle.hxx \
+			AIEscort.cxx AIEscort.hxx \
 			performancedata.cxx performancedata.hxx \
 			performancedb.cxx performancedb.hxx
 

src/Instrumentation/wxradar.cxx

@@ -63,7 +63,10 @@ using std::setfill;
 #include "od_gauge.hxx"
 #include "wxradar.hxx"
 
+#include <iostream>             // for cout, endl
 
+using std::cout;
+using std::endl;
 
 static const float UNIT = 1.0f / 8.0f;  // 8 symbols in a row/column in the texture
 static const char *DEFAULT_FONT = "typewriter.txf";
@@ -78,7 +81,8 @@ wxRadarBg::wxRadarBg(SGPropertyNode *node) :
 _odg(0),
 _last_switchKnob("off"),
 _resultTexture(0),
-    _wxEcho(0)
+_wxEcho(0),
+_antenna_ht(node->getDoubleValue("antenna-ht-ft", 0.0))
 {
     string branch;
     branch = "/instrumentation/" + _name;
@@ -281,8 +285,11 @@ wxRadarBg::update (double delta_time_sec)
         return;
     }
     _time += delta_time_sec;
-    if (_time < _interval)
+    if (_time < _interval){
+//        cout << "WXradar update too soon " << _time << endl;
         return;
+    }
+//        cout << "WXradar updating" << _time<< endl;
 
     _time = 0.0;
 
@@ -293,7 +300,9 @@ wxRadarBg::update (double delta_time_sec)
             center_map();
         }
     } else if (mode == "plan") {
-        _display_mode = PLAN;
+        _display_mode = PLAN;}
+    else if (mode == "bscan") {
+        _display_mode = BSCAN;
     } else {
         _display_mode = ARC;
     }
@@ -358,6 +367,8 @@ wxRadarBg::update (double delta_time_sec)
             if (_radar_rotate_node->getBoolValue()) {
                 _angle_offset = -_view_heading;
             }
+        } else if (_display_mode == BSCAN) {
+            _angle_offset = -_view_heading;
         } else {
             // rose
         }
@@ -458,7 +469,7 @@ wxRadarBg::update (double delta_time_sec)
 void
 wxRadarBg::update_weather()
 {
-    string modeButton = _Instrument->getStringValue("mode", "wx");
+    string modeButton = _Instrument->getStringValue("mode", "WX");
     _radarEchoBuffer = *sgEnviro.get_radar_echo();
 
     // pretend we have a scan angle bigger then the FOV
@@ -586,6 +597,75 @@ wxRadarBg::update_data(const SGPropertyNode *ac, double altitude, double heading
 void
 wxRadarBg::update_aircraft()
 {
+    double diff;
+    double age_factor;
+    double test_rng;
+    double test_brg;
+    double range;
+    double bearing;
+    float echo_radius;
+    double angle;
+
+    if (!ground_echoes.empty()){
+        ground_echoes_iterator = ground_echoes.begin();
+
+        while(ground_echoes_iterator != ground_echoes.end()) {
+            diff = _elapsed_time - (*ground_echoes_iterator)->elapsed_time;
+
+            if( diff > _persistance) {
+                ground_echoes.erase(ground_echoes_iterator);
+            } else {
+//                double test_brg = (*ground_echoes_iterator)->bearing;
+//                double bearing = test_brg * SG_DEGREES_TO_RADIANS;
+//                float angle = calcRelBearing(bearing, _view_heading);
+                double bumpinessFactor  = (*ground_echoes_iterator)->bumpiness;
+                float heading = get_heading();
+                if ( _display_mode == BSCAN ){
+                    test_rng = (*ground_echoes_iterator)->elevation * 6;
+                    test_brg = (*ground_echoes_iterator)->bearing;
+                    angle = calcRelBearingDeg(test_brg, heading) * 6;
+                    range = sqrt(test_rng * test_rng + angle * angle);
+                    bearing = atan2(angle, test_rng);
+                    //cout << "angle " << angle <<" bearing "
+                    //    << bearing / SG_DEGREES_TO_RADIANS <<  endl;
+                    echo_radius = (0.1 + (1.9 * bumpinessFactor)) * 240 * age_factor;
+                } else {
+                    test_rng = (*ground_echoes_iterator)->range;
+                    range = test_rng * SG_METER_TO_NM;
+                    test_brg = (*ground_echoes_iterator)->bearing;
+                    bearing = test_brg * SG_DEGREES_TO_RADIANS;
+                    echo_radius = (0.1 + (1.9 * bumpinessFactor)) * 120 * age_factor;
+                    bearing += _angle_offset;
+                }
+
+                float radius = range * _scale;
+                //double heading = 90 * SG_DEGREES_TO_RADIANS;
+                //heading += _angle_offset;
+
+                age_factor = 1;
+
+                if (diff != 0)
+                    age_factor = 1 - (0.5 * diff/_persistance);
+
+                float size = echo_radius * UNIT;
+
+                const osg::Vec2f texBase(3 * UNIT, 3 * UNIT);
+                osg::Matrixf m(osg::Matrixf::scale(size, size, 1.0f)
+                    * osg::Matrixf::translate(0.0f, radius, 0.0f)
+                    * wxRotate(bearing) * _centerTrans);
+                addQuad(_vertices, _texCoords, m, texBase);
+
+                ++ground_echoes_iterator;
+
+                //cout << "test bearing " << test_brg 
+                //<< " test_rng " << test_rng * SG_METER_TO_NM
+                //<< " persistance " << _persistance
+                //<< endl;
+            }
+
+        }
+
+    }
     if (!_ai_enabled_node->getBoolValue())
         return;
 
@@ -630,11 +710,13 @@ wxRadarBg::update_aircraft()
 
         double echo_radius, sigma;
         const string name = model->getName();
+
+        //cout << "name "<<name << endl;
         if (name == "aircraft" || name == "tanker")
             echo_radius = 1, sigma = 1;
         else if (name == "multiplayer" || name == "wingman" || name == "static")
             echo_radius = 1.5, sigma = 1;
-        else if (name == "ship" || name == "carrier" || name == "storm")
+        else if (name == "ship" || name == "carrier" || name == "escort" ||name == "storm")
             echo_radius = 1.5, sigma = 100;
         else if (name == "thermal")
             echo_radius = 2, sigma = 100;
@@ -652,7 +734,7 @@ wxRadarBg::update_aircraft()
 
         double range, bearing;
         calcRangeBearing(user_lat, user_lon, lat, lon, range, bearing);
-
+        //cout << _antenna_ht << _interval<< endl;
         bool isVisible = withinRadarHorizon(user_alt, alt, range);
 
         if (!isVisible)
@@ -785,15 +867,17 @@ wxRadarBg::withinRadarHorizon(double user_alt, double alt, double range_nm)
 {
     // Radar Horizon  = 1.23(ht^1/2 + hr^1/2),
     //don't allow negative altitudes (an approximation - yes altitudes can be negative)
+    // Allow antenna ht to be set, but only on ground
+    _antenna_ht = _Instrument->getDoubleValue("antenna-ht-ft");
 
-    if (user_alt < 0)
+    if (user_alt <= 0)
-        user_alt = 0;
+        user_alt = _antenna_ht;
 
-    if (alt < 0)
+    if (alt <= 0)
-        alt = 0;
+        alt = 0; // to allow some vertical extent of target
 
     double radarhorizon = 1.23 * (sqrt(alt) + sqrt(user_alt));
-    //SG_LOG(SG_GENERAL, SG_DEBUG, "Radar: horizon " << radarhorizon);
+//    SG_LOG(SG_GENERAL, SG_ALERT, "Radar: radar horizon " << radarhorizon);
     return radarhorizon >= range_nm;
 }
 
@@ -851,6 +935,20 @@ wxRadarBg::calcRelBearing(float bearing, float heading)
     return angle;
 }
 
+float
+wxRadarBg::calcRelBearingDeg(float bearing, float heading)
+{
+    float angle = bearing - heading;
+
+    if (angle >= 180)
+        return angle -= 360;
+
+    if (angle < -180)
+        return angle += 360;
+
+    return angle;
+}
+
 
 void
 wxRadarBg::updateFont()

src/Instrumentation/wxradar.hxx

@@ -33,8 +33,11 @@
 #include <simgear/environment/visual_enviro.hxx>
 
 #include <vector>
+#include <queue>
 #include <string>
+
 using std::vector;
+using std::queue;
 using std::string;
 
 class FGODGauge;
@@ -53,8 +56,10 @@ public:
 protected:
     string _name;
     int _num;
-    double _interval;
     double _time;
+    double _interval;
+    double _elapsed_time;
+    double _persistance;
     bool _sim_init_done;
 
     SGPropertyNode_ptr _serviceable_node;
@@ -68,6 +73,20 @@ protected:
 
     FGODGauge *_odg;
 
+    typedef struct {
+        double bearing;
+        double range;
+        double elevation;
+        double bumpiness;
+        double elapsed_time;
+    }ground_echo;
+
+    typedef vector <ground_echo*> ground_echo_vector_type;
+    typedef ground_echo_vector_type::iterator ground_echo_vector_iterator;
+
+    ground_echo_vector_type       ground_echoes;
+    ground_echo_vector_iterator   ground_echoes_iterator;
+
     // Convenience function for creating a property node with a
     // default value
     template<typename DefaultType>
@@ -76,7 +95,7 @@ protected:
 private:
     string _texture_path;
 
-    typedef enum { ARC, MAP, PLAN, ROSE } DisplayMode;
+    typedef enum { ARC, MAP, PLAN, ROSE, BSCAN} DisplayMode;
     DisplayMode _display_mode;
 
     string _last_switchKnob;
@@ -89,6 +108,7 @@ private:
 
     double _radar_ref_rng;
     double _lat, _lon;
+    double _antenna_ht;
 
     SGPropertyNode_ptr _Tacan;
     SGPropertyNode_ptr _Radar_controls;
@@ -147,6 +167,7 @@ private:
     bool inRadarRange(double sigma, double range);
 
     float calcRelBearing(float bearing, float heading);
+    float calcRelBearingDeg(float bearing, float heading);
 };