Angelopoulos/Blankenbeker Final Project

projects/Assignments/homework3/AngelBlank/ABEspduReceiverA.java

+package AngelBlank;
+
+import java.net.*;
+import java.util.*;
+
+import edu.nps.moves.disutil.*;
+import edu.nps.moves.dis.*;
+
+/**
+ * Receives PDUs from the network in IEEE format.
+ *
+ * @author DMcG
+ * @version $Id:$
+ */
+public class ABEspduReceiverA {
+
+    /** Max size of a PDU in binary format that we can receive. This is actually
+     * somewhat outdated--PDUs can be larger--but this is a reasonable starting point
+     */
+    public static final int MAX_PDU_SIZE = 8192;
+    public static final String GROUP = "239.1.2.3";
+    public static void main(String args[]) {
+        MulticastSocket socket;
+        DatagramPacket packet;
+        InetAddress address;
+        PduFactory pduFactory = new PduFactory();
+        
+        
+
+        try {
+            // Create TCP Bridge
+             ServerSocket serverSocket = new ServerSocket(2999);
+            
+            
+            
+            // Specify the socket to receive data
+            socket = new MulticastSocket(3000);
+            socket.setBroadcast(true);
+       
+            address = InetAddress.getByName(GROUP);
+            socket.joinGroup(address);
+
+            // Loop infinitely, receiving datagrams
+            while (true) {
+                byte buffer[] = new byte[MAX_PDU_SIZE];
+                packet = new DatagramPacket(buffer, buffer.length);
+
+                socket.receive(packet);
+
+                List<Pdu> pduBundle = pduFactory.getPdusFromBundle(packet.getData());
+                System.out.println("Bundle size is " + pduBundle.size());
+                
+                Iterator it = pduBundle.iterator();
+
+                while(it.hasNext())
+                {
+                    Pdu aPdu = (Pdu)it.next();
+                
+                    System.out.print("got PDU of type: " + aPdu.getClass().getName());
+                    if(aPdu instanceof EntityStatePdu)
+                    {
+                        EntityID eid = ((EntityStatePdu)aPdu).getEntityID();
+                        Vector3Double position = ((EntityStatePdu)aPdu).getEntityLocation();
+                        System.out.print(" EID:[" + eid.getSite() + ", " + eid.getApplication() + ", " + eid.getEntity() + "] ");
+                        System.out.print(" Location in DIS coordinates: [" + position.getX() + ", " + position.getY() + ", " + position.getZ() + "]");
+                    }
+                    System.out.println();
+                } // end trop through PDU bundle
+
+            } // end while
+        } // End try
+        catch (Exception e) {
+
+            System.out.println(e);
+        }
+
+
+    } // end main
+} // end class

projects/Assignments/homework3/AngelBlank/ABEspduReceiverB.java

+package AngelBlank;
+
+
+import java.net.*;
+import java.util.*;
+
+import edu.nps.moves.disutil.*;
+import edu.nps.moves.dis.*;
+
+/**
+ * Receives PDUs from the network in IEEE format.
+ *
+ * @author DMcG
+ * @version $Id:$
+ */
+public class ABEspduReceiverB {
+
+    /** Max size of a PDU in binary format that we can receive. This is actually
+     * somewhat outdated--PDUs can be larger--but this is a reasonable starting point
+     */
+    public static final int MAX_PDU_SIZE = 8192;
+    
+    public static final String GROUP = "239.1.2.3";
+
+    public static void main(String args[]) {
+        MulticastSocket socket;
+        DatagramPacket packet;
+        InetAddress address;
+        PduFactory pduFactory = new PduFactory();
+
+        try {
+            // Specify the socket to receive data
+            socket = new MulticastSocket(3000);
+            socket.setBroadcast(true);
+       
+
+            address = InetAddress.getByName(GROUP);
+            socket.joinGroup(address);
+
+            // Loop infinitely, receiving datagrams
+            while (true) {
+                byte buffer[] = new byte[MAX_PDU_SIZE];
+                packet = new DatagramPacket(buffer, buffer.length);
+
+                socket.receive(packet);
+
+                List<Pdu> pduBundle = pduFactory.getPdusFromBundle(packet.getData());
+                System.out.println("Bundle size is " + pduBundle.size());
+                
+                Iterator it = pduBundle.iterator();
+
+                while(it.hasNext())
+                {
+                    Pdu aPdu = (Pdu)it.next();
+                
+                    System.out.print("got PDU of type: " + aPdu.getClass().getName());
+                    if(aPdu instanceof EntityStatePdu)
+                    {
+                        EntityID eid = ((EntityStatePdu)aPdu).getEntityID();
+                        Vector3Double position = ((EntityStatePdu)aPdu).getEntityLocation();
+                        System.out.print(" EID:[" + eid.getSite() + ", " + eid.getApplication() + ", " + eid.getEntity() + "] ");
+                        System.out.print(" Location in DIS coordinates: [" + position.getX() + ", " + position.getY() + ", " + position.getZ() + "]");
+                    }
+                    System.out.println();
+                } // end trop through PDU bundle
+
+            } // end while
+        } // End try
+        catch (Exception e) {
+
+            System.out.println(e);
+        }
+
+
+    } // end main
+} // end class

projects/Assignments/homework3/AngelBlank/ABEspduSenderA.java

+package AngelBlank;
+
+
+import java.io.*;
+import java.net.*;
+import java.util.*;
+
+import edu.nps.moves.dis.*;
+import edu.nps.moves.disutil.CoordinateConversions;
+import edu.nps.moves.disutil.DisTime;
+
+/**
+ * Creates and sends ESPDUs in IEEE binary format. 
+ *
+ * @author DMcG
+ */
+public class ABEspduSenderA 
+{
+    public static final int NUMBER_TO_SEND = 5000;
+
+    public enum NetworkMode{UNICAST, MULTICAST, BROADCAST};
+
+    /** default multicast group we send on */
+    public static final String DEFAULT_MULTICAST_GROUP="239.1.2.3";
+   
+    /** Port we send on */
+    public static final int    DIS_DESTINATION_PORT = 3000;
+    
+/** Possible system properties, passed in via -Dattr=val
+     * networkMode: unicast, broadcast, multicast
+     * destinationIp: where to send the packet. If in multicast mode, this can be mcast.
+     *                To determine bcast destination IP, use an online bcast address
+     *                caclulator, for example http://www.remotemonitoringsystems.ca/broadcast.php
+     *                If in mcast mode, a join() will be done on the mcast address.
+     * port: port used for both source and destination.
+     * @param args 
+     */
+public static void main(String args[])
+{
+    /** an entity state pdu */
+    EntityStatePdu espdu = new EntityStatePdu();
+    MulticastSocket socket = null;
+    DisTime disTime = DisTime.getInstance();
+    int alternator = -1;
+    
+    // ICBM coordinates for my office
+    double lat = 36.595517; 
+    double lon = -121.877000;
+
+    
+    // Default settings. These are used if no system properties are set. 
+    // If system properties are passed in, these are over ridden.
+    int port = DIS_DESTINATION_PORT;
+    NetworkMode mode = NetworkMode.MULTICAST;
+    InetAddress destinationIp = null;
+    
+    try
+    {
+        destinationIp = InetAddress.getByName(DEFAULT_MULTICAST_GROUP);
+    }
+    catch(Exception e)
+    {
+        System.out.println(e + " Cannot create multicast address");
+        System.exit(0);
+    }
+    
+    // All system properties, passed in on the command line via -Dattribute=value
+    Properties systemProperties = System.getProperties();
+    
+    // IP address we send to
+    String destinationIpString = systemProperties.getProperty("destinationIp");
+    
+    // Port we send to, and local port we open the socket on
+    String portString = systemProperties.getProperty("port");
+    
+    // Network mode: unicast, multicast, broadcast
+    String networkModeString = systemProperties.getProperty("networkMode"); // unicast or multicast or broadcast
+        
+
+    // Set up a socket to send information
+    try
+    {
+        // Port we send to
+        if(portString != null)
+            port = Integer.parseInt(portString);
+        
+        socket = new MulticastSocket(port);
+        
+        // Where we send packets to, the destination IP address
+        if(destinationIpString != null)
+        {
+            destinationIp = InetAddress.getByName(destinationIpString);
+        }
+
+        // Type of transport: unicast, broadcast, or multicast
+        if(networkModeString != null)
+        {
+            if(networkModeString.equalsIgnoreCase("unicast"))
+                mode = NetworkMode.UNICAST;
+            else if(networkModeString.equalsIgnoreCase("broadcast"))
+                mode = NetworkMode.BROADCAST;
+            else if(networkModeString.equalsIgnoreCase("multicast"))
+            {
+                mode = NetworkMode.MULTICAST;
+                if(!destinationIp.isMulticastAddress())
+                {
+                    throw new RuntimeException("Sending to multicast address, but destination address " + destinationIp.toString() + "is not multicast");
+                }
+                
+                socket.joinGroup(destinationIp);
+                
+            }
+        } // end networkModeString
+    }
+    catch(Exception e)
+    {
+        System.out.println("Unable to initialize networking. Exiting.");
+        System.out.println(e);
+        System.exit(-1);
+    }
+    
+    // Initialize values in the Entity State PDU object. The exercise ID is 
+    // a way to differentiate between different virtual worlds on one network.
+    // Note that some values (such as the PDU type and PDU family) are set
+    // automatically when you create the ESPDU.
+    espdu.setExerciseID((short)1);
+    
+    // The EID is the unique identifier for objects in the world. This 
+    // EID should match up with the ID for the object specified in the 
+    // VMRL/x3d/virtual world.
+    EntityID eid = espdu.getEntityID();
+    eid.setSite(1);  // 0 is apparently not a valid site number, per the spec
+    eid.setApplication(1); 
+    eid.setEntity(2); 
+    
+    // Set the entity type. SISO has a big list of enumerations, so that by
+    // specifying various numbers we can say this is an M1A2 American tank,
+    // the USS Enterprise, and so on. We'll make this a tank. There is a 
+    // separate project elsehwhere in this project that implements DIS 
+    // enumerations in C++ and Java, but to keep things simple we just use
+    // numbers here.
+    EntityType entityType = espdu.getEntityType();
+    entityType.setEntityKind((short)1);      // Platform (vs lifeform, munition, sensor, etc.)
+    entityType.setCountry(225);              // USA
+    entityType.setDomain((short)1);          // Land (vs air, surface, subsurface, space)
+    entityType.setCategory((short)1);        // Tank
+    entityType.setSubcategory((short)1);     // M1 Abrams
+    entityType.setSpec((short)3);            // M1A2 Abrams
+    
+
+    Set<InetAddress> bcastAddresses = getBroadcastAddresses();
+    // Loop through sending N ESPDUs
+    try
+    {
+        System.out.println("Sending " + NUMBER_TO_SEND + " ESPDU packets to " + destinationIp.toString());
+        for(int idx = 0; idx < NUMBER_TO_SEND; idx++)
+        {
+            // DIS time is a pain in the ass. DIS time units are 2^31-1 units per
+            // hour, and time is set to DIS time units from the top of the hour. 
+            // This means that if you start sending just before the top of the hour
+            // the time units can roll over to zero as you are sending. The receivers
+            // (escpecially homegrown ones) are often not able to detect rollover
+            // and may start discarding packets as dupes or out of order. We use
+            // an NPS timestamp here, hundredths of a second since the start of the
+            // year. The DIS standard for time is often ignored in the wild; I've seen
+            // people use Unix time (seconds since 1970) and more. Or you can
+            // just stuff idx into the timestamp field to get something that is monotonically
+            // increasing.
+            
+            // Note that timestamp is used to detect duplicate and out of order packets. 
+            // That means if you DON'T change the timestamp, many implementations will simply
+            // discard subsequent packets that have an identical timestamp. Also, if they
+            // receive a PDU with an timestamp lower than the last one they received, they
+            // may discard it as an earlier, out-of-order PDU. So it is a good idea to
+            // update the timestamp on ALL packets sent.
+            
+
+            // An alterative approach: actually follow the standard. It's a crazy concept,
+            // but it might just work.
+            int ts = disTime.getDisAbsoluteTimestamp();
+            espdu.setTimestamp(ts);
+            
+            // Set the position of the entity in the world. DIS uses a cartesian 
+            // coordinate system with the origin at the center of the earth, the x
+            // axis out at the equator and prime meridian, y out at the equator and
+            // 90 deg east, and z up and out the north pole. To place an object on
+            // the earth's surface you also need a model for the shape of the earth
+            // (it's not a sphere.) All the fancy math necessary to do this is in
+            // the SEDRIS SRM package. There are also some one-off formulas for 
+            // doing conversions from, for example, lat/lon/altitude to DIS coordinates.
+            // Here we use those one-off formulas.
+
+            // Modify the position of the object. This will send the object a little
+            // due east by adding some to the longitude every iteration. Since we
+            // are on the Pacific coast, this sends the object east. Assume we are
+            // at zero altitude. In other worlds you'd use DTED to determine the
+            // local ground altitude at that lat/lon, or you'd just use ground clamping.
+            // The x and y values will change, but the z value should not.
+            
+            //lon = lon + (double)((double)idx / 100000.0);
+            //System.out.println("lla=" + lat + "," + lon + ", 0.0");
+
+            double direction = Math.pow((double)(-1.0), (double)(idx));
+            lon = lon + (direction * 0.00006);
+            System.out.println(lon);
+            
+            double disCoordinates[] = CoordinateConversions.getXYZfromLatLonDegrees(lat, lon, 1.0);
+            Vector3Double location = espdu.getEntityLocation();
+            location.setX(disCoordinates[0]);
+            location.setY(disCoordinates[1]);
+            location.setZ(disCoordinates[2]);
+            System.out.println("lat, lon:" + lat + ", " + lon);
+            System.out.println("DIS coord:" + disCoordinates[0] + ", " + disCoordinates[1] + ", " + disCoordinates[2]);
+
+            // Optionally, we can do some rotation of the entity
+            /*
+            Orientation orientation = espdu.getEntityOrientation();
+            float psi = orientation.getPsi();
+            psi = psi + idx;
+            orientation.setPsi(psi);
+            orientation.setTheta((float)(orientation.getTheta() + idx /2.0));
+             */
+            
+            // You can set other ESPDU values here, such as the velocity, acceleration,
+            // and so on.
+
+            // Marshal out the espdu object to a byte array, then send a datagram
+            // packet with that data in it.
+            ByteArrayOutputStream baos = new ByteArrayOutputStream();
+            DataOutputStream dos = new DataOutputStream(baos);
+            espdu.marshal(dos);
+
+            FirePdu fire = new FirePdu();
+            byte[] fireArray = fire.marshal();
+            
+            // The byte array here is the packet in DIS format. We put that into a 
+            // datagram and send it.
+            byte[] data = baos.toByteArray();
+
+            bcastAddresses = getBroadcastAddresses();
+            Iterator it = bcastAddresses.iterator();
+            while(it.hasNext())
+            {
+               InetAddress bcast = (InetAddress)it.next();
+               System.out.println("Sending bcast to " + bcast);
+               DatagramPacket packet = new DatagramPacket(data, data.length, bcast, 3000);
+               socket.send(packet);
+               packet = new DatagramPacket(fireArray, fireArray.length, bcast, 3000);
+               //socket.send(packet);
+            }
+            
+            // Send every 1 sec. Otherwise this will be all over in a fraction of a second.
+            Thread.sleep(3000);
+
+            location = espdu.getEntityLocation();
+            
+            System.out.println("Espdu #" + idx + " EID=[" + eid.getSite() + "," + eid.getApplication() + "," + eid.getEntity() + "]");
+            System.out.println(" DIS coordinates location=[" + location.getX() + "," + location.getY() + "," + location.getZ() + "]");
+            double c[] = {location.getX(), location.getY(), location.getZ()};
+            double lla[] = CoordinateConversions.xyzToLatLonDegrees(c);
+//            System.out.println(" Location (lat/lon/alt): [" + lla[0] + ", " + lla[1] + ", " + lla[2] + "]");
+
+        }
+    }
+    catch(Exception e)
+    {
+        System.out.println(e);
+    }
+        
+}
+
+ /**
+    * A number of sites get all snippy about using 255.255.255.255 for a bcast
+    * address; it trips their security software and they kick you off their 
+    * network. (Comcast, NPS.) This determines the bcast address for all
+    * connected interfaces, based on the IP and subnet mask. If you have
+    * a dual-homed host it will return a bcast address for both. If you have
+    * some VMs running on your host this will pick up the addresses for those
+    * as well--eg running VMWare on your laptop with a local IP this will
+    * also pick up a 192.168 address assigned to the VM by the host OS.
+    * 
+    * @return set of all bcast addresses
+    */
+   public static Set<InetAddress> getBroadcastAddresses()
+   {
+       Set<InetAddress> bcastAddresses = new HashSet<InetAddress>();
+       Enumeration interfaces;
+       
+       try
+       {
+           interfaces = NetworkInterface.getNetworkInterfaces();
+           
+           while(interfaces.hasMoreElements())
+           {
+               NetworkInterface anInterface = (NetworkInterface)interfaces.nextElement();
+               
+               if(anInterface.isUp())
+               {
+                   Iterator it = anInterface.getInterfaceAddresses().iterator();
+                   while(it.hasNext())
+                   {
+                       InterfaceAddress anAddress = (InterfaceAddress)it.next();
+                       if((anAddress == null || anAddress.getAddress().isLinkLocalAddress()))
+                           continue;
+                       
+                       //System.out.println("Getting bcast address for " + anAddress);
+                       InetAddress abcast = anAddress.getBroadcast();
+                       if(abcast != null)
+                        bcastAddresses.add(abcast);
+                   }
+               }
+           }
+           
+       }
+       catch(Exception e)
+       {
+           e.printStackTrace();
+           System.out.println(e);
+       }
+       
+       return bcastAddresses;   
+   }
+
+}

projects/Assignments/homework3/AngelBlank/ABEspduSenderB.java

+package AngelBlank;
+
+import java.io.*;
+import java.net.*;
+import java.util.*;
+
+import edu.nps.moves.dis.*;
+import edu.nps.moves.disutil.CoordinateConversions;
+import edu.nps.moves.disutil.DisTime;
+
+/**
+ * Creates and sends ESPDUs in IEEE binary format. 
+ *
+ * @author DMcG
+ */
+public class ABEspduSenderB 
+{
+    public static final int NUMBER_TO_SEND = 5000;
+
+    public enum NetworkMode{UNICAST, MULTICAST, BROADCAST};
+
+    /** default multicast group we send on */
+    public static final String DEFAULT_MULTICAST_GROUP = "239.1.2.3";
+   
+    /** Port we send on */
+    public static final int    DIS_DESTINATION_PORT = 3000;
+    
+/** Possible system properties, passed in via -Dattr=val
+     * networkMode: unicast, broadcast, multicast
+     * destinationIp: where to send the packet. If in multicast mode, this can be mcast.
+     *                To determine bcast destination IP, use an online bcast address
+     *                caclulator, for example http://www.remotemonitoringsystems.ca/broadcast.php
+     *                If in mcast mode, a join() will be done on the mcast address.
+     * port: port used for both source and destination.
+     * @param args 
+     */
+public static void main(String args[])
+{
+    /** an entity state pdu */
+    EntityStatePdu espdu = new EntityStatePdu();
+    MulticastSocket socket = null;
+    DisTime disTime = DisTime.getInstance();
+    int alternator = -1;
+    
+    // ICBM coordinates for my office
+    double lat = 36.595517; 
+    double lon = -121.877000;
+
+    
+    // Default settings. These are used if no system properties are set. 
+    // If system properties are passed in, these are over ridden.
+    int port = DIS_DESTINATION_PORT;
+    NetworkMode mode = NetworkMode.MULTICAST;
+    InetAddress destinationIp = null;
+    
+    try
+    {
+        destinationIp = InetAddress.getByName(DEFAULT_MULTICAST_GROUP);
+    }
+    catch(Exception e)
+    {
+        System.out.println(e + " Cannot create multicast address");
+        System.exit(0);
+    }
+    
+    // All system properties, passed in on the command line via -Dattribute=value
+    Properties systemProperties = System.getProperties();
+    
+    // IP address we send to
+    String destinationIpString = systemProperties.getProperty("destinationIp");
+    
+    // Port we send to, and local port we open the socket on
+    String portString = systemProperties.getProperty("port");
+    
+    // Network mode: unicast, multicast, broadcast
+    String networkModeString = systemProperties.getProperty("networkMode"); // unicast or multicast or broadcast
+        
+
+    // Set up a socket to send information
+    try
+    {
+        // Port we send to
+        if(portString != null)
+            port = Integer.parseInt(portString);
+        
+        socket = new MulticastSocket(port);
+        
+        // Where we send packets to, the destination IP address
+        if(destinationIpString != null)
+        {
+            destinationIp = InetAddress.getByName(destinationIpString);
+        }
+
+        // Type of transport: unicast, broadcast, or multicast
+        if(networkModeString != null)
+        {
+            if(networkModeString.equalsIgnoreCase("unicast"))
+                mode = NetworkMode.UNICAST;
+            else if(networkModeString.equalsIgnoreCase("broadcast"))
+                mode = NetworkMode.BROADCAST;
+            else if(networkModeString.equalsIgnoreCase("multicast"))
+            {
+                mode = NetworkMode.MULTICAST;
+                if(!destinationIp.isMulticastAddress())
+                {
+                    throw new RuntimeException("Sending to multicast address, but destination address " + destinationIp.toString() + "is not multicast");
+                }
+                
+                socket.joinGroup(destinationIp);
+                
+            }
+        } // end networkModeString
+    }
+    catch(Exception e)
+    {
+        System.out.println("Unable to initialize networking. Exiting.");
+        System.out.println(e);
+        System.exit(-1);
+    }
+    
+    // Initialize values in the Entity State PDU object. The exercise ID is 
+    // a way to differentiate between different virtual worlds on one network.
+    // Note that some values (such as the PDU type and PDU family) are set
+    // automatically when you create the ESPDU.
+    espdu.setExerciseID((short)1);
+    
+    // The EID is the unique identifier for objects in the world. This 
+    // EID should match up with the ID for the object specified in the 
+    // VMRL/x3d/virtual world.
+    EntityID eid = espdu.getEntityID();
+    eid.setSite(1);  // 0 is apparently not a valid site number, per the spec
+    eid.setApplication(1); 
+    eid.setEntity(2); 
+    
+    // Set the entity type. SISO has a big list of enumerations, so that by
+    // specifying various numbers we can say this is an M1A2 American tank,
+    // the USS Enterprise, and so on. We'll make this a tank. There is a 
+    // separate project elsehwhere in this project that implements DIS 
+    // enumerations in C++ and Java, but to keep things simple we just use
+    // numbers here.
+    EntityType entityType = espdu.getEntityType();
+    entityType.setEntityKind((short)1);      // Platform (vs lifeform, munition, sensor, etc.)
+    entityType.setCountry(225);              // USA
+    entityType.setDomain((short)1);          // Land (vs air, surface, subsurface, space)
+    entityType.setCategory((short)1);        // Tank
+    entityType.setSubcategory((short)1);     // M1 Abrams
+    entityType.setSpec((short)3);            // M1A2 Abrams
+    
+
+    Set<InetAddress> bcastAddresses = getBroadcastAddresses();
+    // Loop through sending N ESPDUs
+    try
+    {
+        System.out.println("Sending " + NUMBER_TO_SEND + " ESPDU packets to " + destinationIp.toString());
+        for(int idx = 0; idx < NUMBER_TO_SEND; idx++)
+        {
+            // DIS time is a pain in the ass. DIS time units are 2^31-1 units per
+            // hour, and time is set to DIS time units from the top of the hour. 
+            // This means that if you start sending just before the top of the hour
+            // the time units can roll over to zero as you are sending. The receivers
+            // (escpecially homegrown ones) are often not able to detect rollover
+            // and may start discarding packets as dupes or out of order. We use
+            // an NPS timestamp here, hundredths of a second since the start of the
+            // year. The DIS standard for time is often ignored in the wild; I've seen
+            // people use Unix time (seconds since 1970) and more. Or you can
+            // just stuff idx into the timestamp field to get something that is monotonically
+            // increasing.
+            
+            // Note that timestamp is used to detect duplicate and out of order packets. 
+            // That means if you DON'T change the timestamp, many implementations will simply
+            // discard subsequent packets that have an identical timestamp. Also, if they
+            // receive a PDU with an timestamp lower than the last one they received, they
+            // may discard it as an earlier, out-of-order PDU. So it is a good idea to
+            // update the timestamp on ALL packets sent.
+            
+
+            // An alterative approach: actually follow the standard. It's a crazy concept,
+            // but it might just work.
+            int ts = disTime.getDisAbsoluteTimestamp();
+            espdu.setTimestamp(ts);
+            
+            // Set the position of the entity in the world. DIS uses a cartesian 
+            // coordinate system with the origin at the center of the earth, the x
+            // axis out at the equator and prime meridian, y out at the equator and
+            // 90 deg east, and z up and out the north pole. To place an object on
+            // the earth's surface you also need a model for the shape of the earth
+            // (it's not a sphere.) All the fancy math necessary to do this is in
+            // the SEDRIS SRM package. There are also some one-off formulas for 
+            // doing conversions from, for example, lat/lon/altitude to DIS coordinates.
+            // Here we use those one-off formulas.
+
+            // Modify the position of the object. This will send the object a little
+            // due east by adding some to the longitude every iteration. Since we
+            // are on the Pacific coast, this sends the object east. Assume we are
+            // at zero altitude. In other worlds you'd use DTED to determine the
+            // local ground altitude at that lat/lon, or you'd just use ground clamping.
+            // The x and y values will change, but the z value should not.
+            
+            //lon = lon + (double)((double)idx / 100000.0);
+            //System.out.println("lla=" + lat + "," + lon + ", 0.0");
+
+            double direction = Math.pow((double)(-1.0), (double)(idx));
+            lon = lon + (direction * 0.00006);
+            System.out.println(lon);
+            
+            double disCoordinates[] = CoordinateConversions.getXYZfromLatLonDegrees(lat, lon, 1.0);
+            Vector3Double location = espdu.getEntityLocation();
+            location.setX(disCoordinates[0]);
+            location.setY(disCoordinates[1]);
+            location.setZ(disCoordinates[2]);
+            System.out.println("lat, lon:" + lat + ", " + lon);
+            System.out.println("DIS coord:" + disCoordinates[0] + ", " + disCoordinates[1] + ", " + disCoordinates[2]);
+
+            // Optionally, we can do some rotation of the entity
+            /*
+            Orientation orientation = espdu.getEntityOrientation();
+            float psi = orientation.getPsi();
+            psi = psi + idx;
+            orientation.setPsi(psi);
+            orientation.setTheta((float)(orientation.getTheta() + idx /2.0));
+             */
+            
+            // You can set other ESPDU values here, such as the velocity, acceleration,
+            // and so on.
+
+            // Marshal out the espdu object to a byte array, then send a datagram
+            // packet with that data in it.
+            ByteArrayOutputStream baos = new ByteArrayOutputStream();
+            DataOutputStream dos = new DataOutputStream(baos);
+            espdu.marshal(dos);
+
+            FirePdu fire = new FirePdu();
+            byte[] fireArray = fire.marshal();
+            
+            // The byte array here is the packet in DIS format. We put that into a 
+            // datagram and send it.
+            byte[] data = baos.toByteArray();
+
+            bcastAddresses = getBroadcastAddresses();
+            Iterator it = bcastAddresses.iterator();
+            while(it.hasNext())
+            {
+               InetAddress bcast = (InetAddress)it.next();
+               System.out.println("Sending bcast to " + bcast);
+               DatagramPacket packet = new DatagramPacket(data, data.length, bcast, 3000);
+               socket.send(packet);
+               packet = new DatagramPacket(fireArray, fireArray.length, bcast, 3000);
+               //socket.send(packet);
+            }
+            
+            // Send every 1 sec. Otherwise this will be all over in a fraction of a second.
+            Thread.sleep(3000);
+
+            location = espdu.getEntityLocation();
+            
+            System.out.println("Espdu #" + idx + " EID=[" + eid.getSite() + "," + eid.getApplication() + "," + eid.getEntity() + "]");
+            System.out.println(" DIS coordinates location=[" + location.getX() + "," + location.getY() + "," + location.getZ() + "]");
+            double c[] = {location.getX(), location.getY(), location.getZ()};
+            double lla[] = CoordinateConversions.xyzToLatLonDegrees(c);
+//            System.out.println(" Location (lat/lon/alt): [" + lla[0] + ", " + lla[1] + ", " + lla[2] + "]");
+
+        }
+    }
+    catch(Exception e)
+    {
+        System.out.println(e);
+    }
+        
+}
+
+ /**
+    * A number of sites get all snippy about using 255.255.255.255 for a bcast
+    * address; it trips their security software and they kick you off their 
+    * network. (Comcast, NPS.) This determines the bcast address for all
+    * connected interfaces, based on the IP and subnet mask. If you have
+    * a dual-homed host it will return a bcast address for both. If you have
+    * some VMs running on your host this will pick up the addresses for those
+    * as well--eg running VMWare on your laptop with a local IP this will
+    * also pick up a 192.168 address assigned to the VM by the host OS.
+    * 
+    * @return set of all bcast addresses
+    */
+   public static Set<InetAddress> getBroadcastAddresses()
+   {
+       Set<InetAddress> bcastAddresses = new HashSet<InetAddress>();
+       Enumeration interfaces;
+       
+       try
+       {
+           interfaces = NetworkInterface.getNetworkInterfaces();
+           
+           while(interfaces.hasMoreElements())
+           {
+               NetworkInterface anInterface = (NetworkInterface)interfaces.nextElement();
+               
+               if(anInterface.isUp())
+               {
+                   Iterator it = anInterface.getInterfaceAddresses().iterator();
+                   while(it.hasNext())
+                   {
+                       InterfaceAddress anAddress = (InterfaceAddress)it.next();
+                       if((anAddress == null || anAddress.getAddress().isLinkLocalAddress()))
+                           continue;
+                       
+                       //System.out.println("Getting bcast address for " + anAddress);
+                       InetAddress abcast = anAddress.getBroadcast();
+                       if(abcast != null)
+                        bcastAddresses.add(abcast);
+                   }
+               }
+           }
+           
+       }
+       catch(Exception e)
+       {
+           e.printStackTrace();
+           System.out.println(e);
+       }
+       
+       return bcastAddresses;   
+   }
+
+}