void gaussMixMapClient_MsgReceived(object sender, MsgReceivedEventArgs <GlobalMapCell> e)
        {
            isWorking = true;

            if (globalHeightMap == null)
            {
                double globalMapResolution = e.message.DataList[0].largeU; // first index has grid information
                double globalMapExtent     = e.message.DataList[0].largeSig;
                globalHeightMap          = new OccupancyGrid2D(globalMapResolution, globalMapResolution, globalMapExtent, globalMapExtent);
                globalSigMap             = new OccupancyGrid2D(globalHeightMap);
                globalPijMap             = new OccupancyGrid2D(globalHeightMap);
                laserHitMap              = new OccupancyGrid2D(globalHeightMap);
                thresholdGlobalHeightMap = new OccupancyGrid2D(globalHeightMap);
            }
            // if message is received, update the 3 gridmap
            GlobalGaussianMixMap.ConvertToOcGrid(ref globalHeightMap, ref globalSigMap, ref globalPijMap, ref laserHitMap,
                                                 e.message.DataList);
            for (int i = 0; i < globalHeightMap.NumCellX; i++)
            {
                for (int j = 0; j < globalHeightMap.NumCellY; j++)
                {
                    if (globalPijMap.GetCellByIdx(i, j) > 1)
                    {
                        thresholdGlobalHeightMap.SetCellByIdx(i, j, globalHeightMap.GetCellByIdx(i, j));
                    }
                    else
                    {
                        thresholdGlobalHeightMap.SetCellByIdx(i, j, 0);
                    }
                }
            }
        }
        /// <summary>
        /// Get difference of two occupancy map
        /// </summary>
        /// <param name="globalMulti">ocGrid1</param>
        /// <param name="globalSingle">ocGrid2</param>
        /// <param name="currentPose">current position</param>
        /// <param name="extentX">x-length of the comparison</param>
        /// <param name="extentY">y-length of the comparison</param>
        /// <returns>list of index classes - has ocGrid1 value</returns>
        public UpdateMapDataMessage Diff(int robotID, OccupancyGrid2D globalMulti, RobotPose currentPose, double extentX, double extentY)
        {
            if (!globalOcGridByEachRobotAlgorithm.ContainsKey(robotID))
            {
                return(null);
            }
            OccupancyGrid2D globalSingle = globalOcGridByEachRobotAlgorithm[robotID].UhatGM;
            //OccupancyGrid2D globalSingle = globalOcGridByEachRobot[robotID];
            //List<Index> diffIndexToSend = new List<Index>();
            List <Position> diffPositionToSend = new List <Position>();
            //List<float> heightList = new List<float>();
            //List<float> covList = new List<float>();
            //List<float> pijList = new List<float>();

            List <float> pijSum          = new List <float>();
            List <float> puHat           = new List <float>();
            List <float> puHatSquare     = new List <float>();
            List <float> pSigUhateSquare = new List <float>();

            int numCellXHalf = (int)(extentX / globalMulti.ResolutionX);
            int numCellYHalf = (int)(extentY / globalMulti.ResolutionY);
            int currentCellX, currentCellY;

            globalMulti.GetIndicies(currentPose.x, currentPose.y, out currentCellX, out currentCellY);
            int comparisonCellX, comparisonCellY;

            for (int i = 0; i < numCellYHalf * 2; i++)             // [i, j] = [column, row]
            {
                for (int j = 0; j < numCellXHalf * 2; j++)
                {
                    comparisonCellX = currentCellX - numCellXHalf + j;
                    comparisonCellY = currentCellY - numCellYHalf + i;
                    if (globalMulti.GetCellByIdx(comparisonCellX, comparisonCellY) != globalSingle.GetCellByIdx(comparisonCellX, comparisonCellY))
                    {
                        double x, y; globalMulti.GetReals(comparisonCellX, comparisonCellY, out x, out y);
                        diffPositionToSend.Add(new Position((float)x, (float)y));
                        //heightList.Add((float)gaussianMixMapAlgorithm.UhatGM.GetCellByIdx(j, i));
                        //covList.Add((float)gaussianMixMapAlgorithm.Psig_u_hat_square.GetCellByIdx(j, i));
                        //pijList.Add((float)gaussianMixMapAlgorithm.Pij_sum.GetCellByIdx(j, i));
                        pijSum.Add((float)gaussianMixMapAlgorithm.Pij_sum.GetCell(x, y));
                        puHat.Add((float)gaussianMixMapAlgorithm.Pu_hat.GetCell(x, y));
                        puHatSquare.Add((float)gaussianMixMapAlgorithm.Pu_hat_square.GetCell(x, y));
                        pSigUhateSquare.Add((float)gaussianMixMapAlgorithm.Psig_u_hat_square.GetCell(x, y));
                    }
                }
            }
            return(new UpdateMapDataMessage(robotID, diffPositionToSend, pijSum, puHat, puHatSquare, pSigUhateSquare));
        }
Beispiel #3
0
        public List <Polygon> GetClosed()
        {
            List <Polygon> pixels = new List <Polygon>();

            for (int i = 0; i < closed.Width; i++)
            {
                for (int j = 0; j < closed.Height; j++)
                {
                    if (closed.GetCellByIdx(i, j) != 0)
                    {
                        pixels.Add(DrawPixel((i - extentX / resX) * resX, (j - extentY / resY) * resY));
                    }
                }
            }

            return(pixels);
        }
        /// <summary>
        /// Returns arrays to send out through messaging
        /// </summary>
        /// <param name="largeUDiff"></param>
        /// <param name="largeSigDiff"></param>
        /// <param name="pijDiff"></param>
        /// <param name="colIdx"></param>
        /// <param name="rowIdx"></param>
        public void GetArraysToSend(out List <Index> indexList, out List <float> heightList, out List <float> covList, out List <float> pijSumList, out List <float> laserHitList)
        {
            int index = 0;

            if (indicesDictionary == null)
            {
                indexList    = new List <Index>();
                heightList   = new List <float>();
                covList      = new List <float>();
                pijSumList   = new List <float>();
                laserHitList = new List <float>();
                return;
            }
            else
            {
                indexList    = new List <Index>(indicesDictionary.Count);
                heightList   = new List <float>(indicesDictionary.Count);
                covList      = new List <float>(indicesDictionary.Count);
                pijSumList   = new List <float>(indicesDictionary.Count);
                laserHitList = new List <float>(indicesDictionary.Count);
            }

            lock (locker)
            {
                foreach (KeyValuePair <Index, int> pair in indicesDictionary)
                {
                    indexList.Add(pair.Key);
                    heightList.Add((float)uhatGM.GetCellByIdx(pair.Key.Col, pair.Key.Row));
                    covList.Add((float)sigSqrGM.GetCellByIdx(pair.Key.Col, pair.Key.Row));
                    pijSumList.Add((float)pij_sum.GetCellByIdx(pair.Key.Col, pair.Key.Row));
                    laserHitList.Add((float)laserHit.GetCellByIdx(pair.Key.Col, pair.Key.Row));
                }
                indicesDictionary.Clear();
            }

            //indexList = new List<Index>(this.indicesList);
            //heightList = new List<float>(this.heightList);
            //covList = new List<float>(this.covList);
            //pijSumList = new List<float>(this.pijSumList);

            //this.indicesList.Clear();
            //this.heightList.Clear();
            //this.covList.Clear();
            //this.pijSumList.Clear();
            //this.indicesDictionary.Clear();
        }
Beispiel #5
0
        public List <Waypoint> FindPath(Waypoint start, Waypoint goal, OccupancyGrid2D og, out bool success)
        {
            List <Waypoint> path = new List <Waypoint>();

            //added by aaron (sort of a hack)
            if (og == null || goal.Coordinate.DistanceTo(start.Coordinate) == 0)
            {
                path.Add(new Waypoint(start.Coordinate, true, 0));
                success = true;
                return(path);
            }

            int xIdx, yIdx;

            success = true;
            Vector2[] NESWVector = new Vector2[4];
            Vector2[] diagVector = new Vector2[4];
            bool[]    NESW       = new bool[4];
            Vector2   startV     = start.Coordinate;     // Start Vector2
            Vector2   goalV      = goal.Coordinate;      // Goal Vector2

            PriorityQueue open = new PriorityQueue();

            closed = new OccupancyGrid2D(resX, resY, extentX, extentY);
            opened = new OccupancyGrid2D(resX, resY, extentX, extentY);

            GetIndicies(startV.X, startV.Y, out xIdx, out yIdx);
            startV = new Vector2(xIdx, yIdx);
            GetIndicies(goalV.X, goalV.Y, out xIdx, out yIdx);
            goalV = new Vector2(xIdx, yIdx);

            Node root = new Node(goalV, goalV.DistanceTo(startV), 0, null);

            Node current = root;

            open.Push(current);

            // Do the spreading/discovering stuff until we discover a path.
            while (current.xy != startV)
            {
                if (open.q.Count == 0 || open.q.Count > MAX_OPEN)
                {
                    Console.WriteLine("Failure in DSstar. Open count is: " + open.q.Count);
                    success = false;
                    break;
                }
                current = open.Pop();

                NESWVector[0] = new Vector2(current.xy.X, current.xy.Y - 1);
                NESWVector[1] = new Vector2(current.xy.X + 1, current.xy.Y);
                NESWVector[2] = new Vector2(current.xy.X, current.xy.Y + 1);
                NESWVector[3] = new Vector2(current.xy.X - 1, current.xy.Y);

                diagVector[0] = new Vector2(current.xy.X + 1, current.xy.Y - 1);
                diagVector[1] = new Vector2(current.xy.X + 1, current.xy.Y + 1);
                diagVector[2] = new Vector2(current.xy.X - 1, current.xy.Y + 1);
                diagVector[3] = new Vector2(current.xy.X - 1, current.xy.Y - 1);

                for (int i = 0; i < 4; i++)
                {
                    if ((int)og.GetCellByIdx((int)NESWVector[i].X, (int)NESWVector[i].Y) < 255)
                    {
                        if (closed.GetCellByIdx((int)NESWVector[i].X, (int)NESWVector[i].Y) == 0)
                        {
                            NESW[i] = true;
                            if (opened.GetCellByIdx((int)NESWVector[i].X, (int)NESWVector[i].Y) == 0)
                            {
                                open.Push(new Node(NESWVector[i], NESWVector[i].DistanceTo(startV), current.h + 1
                                                   + og.GetCellByIdx((int)NESWVector[i].X, (int)NESWVector[i].Y) / blurWeight, current));
                                opened.SetCellByIdx((int)NESWVector[i].X, (int)NESWVector[i].Y, 1);
                            }
                        }
                    }
                }

                for (int i = 0; i < 4; i++)
                {
                    if (NESW[i % 4] && NESW[(i + 1) % 4])
                    {
                        if (og.GetCellByIdx((int)diagVector[i].X, (int)diagVector[i].Y) < 255)
                        {
                            if (closed.GetCellByIdx((int)diagVector[i].X, (int)diagVector[i].Y) == 0)
                            {
                                if (opened.GetCellByIdx((int)diagVector[i].X, (int)diagVector[i].Y) == 0)
                                {
                                    open.Push(new Node(diagVector[i], diagVector[i].DistanceTo(startV), current.h + 1.4
                                                       + og.GetCellByIdx((int)diagVector[i].X, (int)diagVector[i].Y) / blurWeight, current));
                                    opened.SetCellByIdx((int)diagVector[i].X, (int)diagVector[i].Y, 1);
                                }
                            }
                        }
                    }
                }

                for (int i = 0; i < 4; i++)
                {
                    NESW[i] = false;
                }

                closed.SetCellByIdx((int)current.xy.X, (int)current.xy.Y, 1);
            }

            // Build a path using the discovered path.
            double   x, y;
            Waypoint waypoint;

            // First waypoint is a user waypoint
            GetReals((int)current.xy.X, (int)current.xy.Y, out x, out y);
            waypoint = new Waypoint(x + resX / 2, y + resY / 2, true, og.GetCellByIdx((int)current.xy.X, (int)current.xy.Y));
            path.Add(waypoint);
            current = current.dad;

            // Middle waypoints are path waypoints
            while (current != root && current != null)
            {
                GetReals((int)current.xy.X, (int)current.xy.Y, out x, out y);
                waypoint = new Waypoint(x + resX / 2, y + resY / 2, false, og.GetCellByIdx((int)current.xy.X, (int)current.xy.Y));
                path.Add(waypoint);
                current = current.dad;
            }

            // Last waypoint is a user waypoint
            if (current != null)
            {
                GetReals((int)current.xy.X, (int)current.xy.Y, out x, out y);
                waypoint = new Waypoint(x + resX / 2, y + resY / 2, true, og.GetCellByIdx((int)current.xy.X, (int)current.xy.Y));
                path.Add(waypoint);
            }

            return(path);
        }
        /// <summary>
        /// Update OccupancyGrid based on lidarScan and robotPose received
        /// </summary>
        /// <param name="lidarScan"></param>
        /// <param name="currentRobotPose"></param>
        public void UpdateOccupancyGrid(ILidarScan <ILidar2DPoint> lidarScan, int robotID, RobotPose currentRobotPose, SensorPose lidarPose, List <Polygon> dynamicObstacles)
        {
            if (lidarPose == null)
            {
                lidarPose = new SensorPose(0, 0, 0.5, 0, 0 * Math.PI / 180.0, 0, 0);
            }
            if (laser2RobotTransMatrixDictionary.ContainsKey(robotID))
            {
                JTpl            = jacobianLaserPoseDictionary[robotID];
                laserToRobotDCM = laser2RobotTransMatrixDictionary[robotID];
            }
            else
            {
                Matrix4 laser2RobotDCM = Matrix4.FromPose(lidarPose);
                for (int i = 0; i < 4; i++)
                {
                    for (int j = 0; j < 4; j++)
                    {
                        laserToRobotDCM[i, j] = laser2RobotDCM[i, j];
                    }
                }
                laser2RobotTransMatrixDictionary.Add(robotID, laserToRobotDCM);
                jacobianLaserPoseDictionary.Add(robotID, ComputeJacobian(lidarPose.yaw, lidarPose.pitch, lidarPose.roll));
                JTpl = jacobianLaserPoseDictionary[robotID];
            }

            // calculate robot2global transformation matrix
            Matrix4 robot2GlocalDCM = Matrix4.FromPose(currentRobotPose);

            for (int i = 0; i < 4; i++)
            {
                for (int j = 0; j < 4; j++)
                {
                    robotToGlocalDCM[i, j] = robot2GlocalDCM[i, j];
                }
            }

            if (lidarScan == null)
            {
                return;
            }
            Stopwatch sw1 = new Stopwatch();
            Stopwatch sw2 = new Stopwatch();
            Stopwatch sw3 = new Stopwatch();
            Stopwatch sw4 = new Stopwatch();
            Stopwatch sw5 = new Stopwatch();
            Stopwatch sw6 = new Stopwatch();


            UMatrix        JTpr = ComputeJacobian(currentRobotPose.yaw, currentRobotPose.pitch, currentRobotPose.roll);
            List <UMatrix> JfPrCubixLaserToRobotDCM  = new List <UMatrix>(6);
            List <UMatrix> RobotToGlocalDCMJfPlCubix = new List <UMatrix>(6);

            for (int i = 0; i < 6; i++)
            {
                //derivative of the robot transform matrtix w.r.t. some element of the robot psoe
                UMatrix j = new UMatrix(4, 4);
                j[0, 0] = JTpr[0, i]; j[1, 0] = JTpr[1, i]; j[2, 0] = JTpr[2, i]; j[3, 0] = JTpr[3, i];
                j[0, 1] = JTpr[4, i]; j[1, 1] = JTpr[5, i]; j[2, 1] = JTpr[6, i]; j[3, 1] = JTpr[7, i];
                j[0, 2] = JTpr[8, i]; j[1, 2] = JTpr[9, i]; j[2, 2] = JTpr[10, i]; j[3, 2] = JTpr[11, i];
                j[0, 3] = JTpr[12, i]; j[1, 3] = JTpr[13, i]; j[2, 3] = JTpr[14, i]; j[3, 3] = JTpr[15, i];
                JfPrCubixLaserToRobotDCM.Add(j * laserToRobotDCM);

                UMatrix tempJacobianPl = new UMatrix(4, 4);
                tempJacobianPl[0, 0] = JTpl[0, i]; tempJacobianPl[1, 0] = JTpl[1, i]; tempJacobianPl[2, 0] = JTpl[2, i]; tempJacobianPl[3, 0] = JTpl[3, i];
                tempJacobianPl[0, 1] = JTpl[4, i]; tempJacobianPl[1, 1] = JTpl[5, i]; tempJacobianPl[2, 1] = JTpl[6, i]; tempJacobianPl[3, 1] = JTpl[7, i];
                tempJacobianPl[0, 2] = JTpl[8, i]; tempJacobianPl[1, 2] = JTpl[9, i]; tempJacobianPl[2, 2] = JTpl[10, i]; tempJacobianPl[3, 2] = JTpl[11, i];
                tempJacobianPl[0, 3] = JTpl[12, i]; tempJacobianPl[1, 3] = JTpl[13, i]; tempJacobianPl[2, 3] = JTpl[14, i]; tempJacobianPl[3, 3] = JTpl[15, i];
                RobotToGlocalDCMJfPlCubix.Add(robotToGlocalDCM * tempJacobianPl);
            }
            UMatrix laserToENU = robotToGlocalDCM * laserToRobotDCM;
            UMatrix pijCell    = new UMatrix(rangeToApply * 2 + 1, rangeToApply * 2 + 1);

            // update covariance
            UpdateCovariance(currentRobotPose.covariance);

            //SickPoint p = new SickPoint(new RThetaCoordinate(1.0f, 0.0f));
            for (int laserIndex = 0; laserIndex < lidarScan.Points.Count; laserIndex++)
            {
                lock (locker)
                {
                    ILidar2DPoint p = lidarScan.Points[laserIndex];
                    if (p.RThetaPoint.R >= MAXRANGE)
                    {
                        continue;
                    }

                    bool hitDynamicObstacles = false;
                    // figure out if this lidar point is hitting other robot

                    // find laser points in 3D space
                    // first define 2D point on the laser plane
                    UMatrix laserPoint = new UMatrix(4, 1);

                    double deg           = (p.RThetaPoint.theta * 180.0 / Math.PI);
                    int    thetaDegIndex = (int)Math.Round((deg + 90.0) * 2.0) % 360;
                    double cosTheta      = cosLookup[thetaDegIndex];
                    double sinTheta      = sinLookup[thetaDegIndex];

                    laserPoint[0, 0] = p.RThetaPoint.R * cosTheta;
                    laserPoint[1, 0] = p.RThetaPoint.R * sinTheta;
                    laserPoint[2, 0] = 0;
                    laserPoint[3, 0] = 1;

                    //calculate r_hat_ENU
                    UMatrix r_hat_ENU = laserToENU * laserPoint;

                    foreach (Polygon dp in dynamicObstacles)
                    {
                        if (dp.IsInside(new Vector2(r_hat_ENU[0, 0], r_hat_ENU[1, 0])))
                        {
                            hitDynamicObstacles = true;
                            break;
                        }
                    }
                    if (hitDynamicObstacles)
                    {
                        continue;
                    }

                    //-------------------------------//
                    // COVARIANCE UMatrix CALCULATION //
                    //-------------------------------//
                    UMatrix JRr = new UMatrix(4, 2);
                    JRr.Zero();
                    JRr[0, 0] = cosTheta;
                    JRr[0, 1] = -p.RThetaPoint.R * sinTheta;
                    JRr[1, 0] = sinTheta;
                    JRr[1, 1] = p.RThetaPoint.R * cosTheta;

                    UMatrix Jfr = new UMatrix(3, 2);                // 3x2
                    Jfr = (laserToENU * JRr).Submatrix(0, 2, 0, 1); // 4x4 * 4x4 * 4x2

                    UMatrix Jfpr = new UMatrix(3, 6);
                    UMatrix Jfpl = new UMatrix(3, 6);
                    sw1.Reset();
                    sw1.Start();

                    for (int i = 0; i < 6; i++)                                        //for each state var (i.e. x,y,z,y,p,r)
                    {
                        UMatrix JfprTemp = (JfPrCubixLaserToRobotDCM[i]) * laserPoint; // 4 by 1 UMatrix
                        Jfpr[0, i] = JfprTemp[0, 0];
                        Jfpr[1, i] = JfprTemp[1, 0];
                        Jfpr[2, i] = JfprTemp[2, 0];

                        //UMatrix JfplTemp = (RobotToGlocalDCMJfPlCubix[i]) * laserPoint; // 4 by 1 UMatrix
                        //Jfpl[0, i] = JfplTemp[0, 0];
                        //Jfpl[1, i] = JfplTemp[1, 0];
                        //Jfpl[2, i] = JfplTemp[2, 0];
                    }
                    sw1.Stop();
                    sw2.Reset();
                    sw2.Start();
                    UMatrix JfprQprJfprT = new UMatrix(3, 3);
                    UMatrix JfplQplJfplT = new UMatrix(3, 3);
                    UMatrix JfrQrJfrT    = new UMatrix(3, 3);
                    JfprQprJfprT = (Jfpr * covRobotPose) * Jfpr.Transpose();
                    //JfplQplJfplT = (Jfpl * covLaserPose) * Jfpl.Transpose();
                    JfrQrJfrT = (Jfr * covLaserScan) * Jfr.Transpose();

                    // add above variables together and get the covariance
                    UMatrix covRHatENU = JfprQprJfprT + /*JfplQplJfplT +*/ JfrQrJfrT; // 3x3 UMatrix
                    sw2.Stop();
                    sw3.Reset();
                    sw3.Start();
                    //-----------------------------//
                    // FIND WHICH CELLS TO COMPUTE //
                    //-----------------------------//

                    // find out cells around this laser point
                    int laserPointIndexX = 0;
                    int laserPointIndexY = 0;
                    //this is used just to do the transformation from reaal to grid and visa versa
                    psig_u_hat_square.GetIndicies(r_hat_ENU[0, 0], r_hat_ENU[1, 0], out laserPointIndexX, out laserPointIndexY); // get cell (r_hat_ENU_X, r_hat_ENU_y)
                    sw3.Stop();
                    sw4.Reset();
                    sw4.Start();
                    //-----------------------------------------//
                    // COMPUTE THE DISTRIBUTION OF UNCERTAINTY //
                    //-----------------------------------------//

                    double sigX       = Math.Sqrt(covRHatENU[0, 0]);
                    double sigY       = Math.Sqrt(covRHatENU[1, 1]);
                    double rho        = covRHatENU[1, 0] / (sigX * sigY);
                    double logTerm    = Math.Log(2 * Math.PI * sigX * sigY * Math.Sqrt(1 - (rho * rho)));
                    double xTermDenom = (1 - (rho * rho));
                    for (int i = -rangeToApply; i <= rangeToApply; i++)     // column
                    {
                        for (int j = -rangeToApply; j <= rangeToApply; j++) // row
                        {
                            // estimate using Bivariate Normal Distribution
                            double posX = 0; double posY = 0;
                            psig_u_hat_square.GetReals(laserPointIndexX + i, laserPointIndexY + j, out posX, out posY);
                            posX += psig_u_hat_square.ResolutionX / 2;
                            posY += psig_u_hat_square.ResolutionY / 2;
                            double x = posX - r_hat_ENU[0, 0];
                            double y = posY - r_hat_ENU[1, 0];
                            double z = (x * x) / (sigX * sigX) -
                                       (2 * rho * x * y / (sigX * sigY)) +
                                       (y * y) / (sigY * sigY);
                            double xTerm = -0.5 * z / xTermDenom;
                            // chi2 test
                            //if ((2 * (1 - (rho * rho))) * ((x * x) / (sigX * sigX) + (y * y) / (sigY * sigY) - (2 * rho * x * y) / (sigX * sigY)) > 15.2)
                            //  continue;
                            pijCell[j + rangeToApply, i + rangeToApply] = Math.Exp(xTerm - logTerm) * psig_u_hat_square.ResolutionX * psig_u_hat_square.ResolutionY;
                            laserHit.SetCellByIdx(laserPointIndexX + i, laserPointIndexY + j, laserHit.GetCellByIdx(laserPointIndexX + i, laserPointIndexY + j) + 1);
                        }
                    }
                    sw4.Stop();
                    sw5.Reset();
                    sw5.Start();

                    //---------------------------//
                    // COMPUTE HEIGHT ESTIMATION //
                    //---------------------------//
                    //				Matrix2 PEN = new Matrix2(covRHatENU[0, 0], covRHatENU[0, 1], covRHatENU[1, 0], covRHatENU[1, 1]);

                    UMatrix PEN = covRHatENU.Submatrix(0, 1, 0, 1);

                    UMatrix PENInv = PEN.Inverse2x2;

                    UMatrix PuEN          = new UMatrix(1, 2);
                    UMatrix PENu          = new UMatrix(2, 1);
                    UMatrix PuENPENInv    = PuEN * PENInv;
                    UMatrix uHatMatrix    = new UMatrix(rangeToApply * 2 + 1, rangeToApply * 2 + 1);
                    UMatrix sigUHatMatrix = new UMatrix(rangeToApply * 2 + 1, rangeToApply * 2 + 1);

                    PuEN[0, 0] = covRHatENU[2, 0];
                    PuEN[0, 1] = covRHatENU[2, 1];

                    PENu[0, 0] = covRHatENU[0, 2];
                    PENu[1, 0] = covRHatENU[1, 2];

                    double sig_u_hat_product = (PuENPENInv * PENu)[0, 0];   // output = 1x1 UMatrix

                    for (int i = -rangeToApply; i <= rangeToApply; i++)     // column
                    {
                        for (int j = -rangeToApply; j <= rangeToApply; j++) // row
                        {
                            UMatrix ENmr_EN = new UMatrix(2, 1);
                            double  posX = 0; double posY = 0;
                            psig_u_hat_square.GetReals(laserPointIndexX + i, laserPointIndexY + j, out posX, out posY);
                            ENmr_EN[0, 0] = posX - r_hat_ENU[0, 0];
                            ENmr_EN[1, 0] = posY - r_hat_ENU[1, 0];
                            double u_hat_product = (PuENPENInv * (ENmr_EN))[0, 0]; // output = 1x1 UMatrix
                            uHatMatrix[j + rangeToApply, i + rangeToApply]    = r_hat_ENU[2, 0] + u_hat_product;
                            sigUHatMatrix[j + rangeToApply, i + rangeToApply] = covRHatENU[2, 2] - sig_u_hat_product;
                        }
                    }
                    sw5.Stop();
                    sw6.Reset();
                    sw6.Start();

                    //-------------------------------------------//
                    // ASSIGN FINAL VALUES TO THE OCCUPANCY GRID //
                    //-------------------------------------------//
                    for (int i = -rangeToApply; i <= rangeToApply; i++)
                    {
                        for (int j = -rangeToApply; j <= rangeToApply; j++)
                        {
                            int indexXToUpdate = laserPointIndexX + i;
                            int indexYToUpdate = laserPointIndexY + j;
                            // if the cell to update is out of range, continue
                            if (!psig_u_hat_square.CheckValidIdx(indexXToUpdate, indexYToUpdate))
                            {
                                //Console.WriteLine("Laser points out of the occupancy grid map");
                                continue;
                            }

                            pij_sum.SetCellByIdx(indexXToUpdate, indexYToUpdate,
                                                 pijCell[j + rangeToApply, i + rangeToApply] + pij_sum.GetCellByIdx(indexXToUpdate, indexYToUpdate));
                            pu_hat.SetCellByIdx(indexXToUpdate, indexYToUpdate,
                                                pijCell[j + rangeToApply, i + rangeToApply] * uHatMatrix[j + rangeToApply, i + rangeToApply] + pu_hat.GetCellByIdx(indexXToUpdate, indexYToUpdate));
                            pu_hat_square.SetCellByIdx(indexXToUpdate, indexYToUpdate,
                                                       pijCell[j + rangeToApply, i + rangeToApply] * uHatMatrix[j + rangeToApply, i + rangeToApply] * uHatMatrix[j + rangeToApply, i + rangeToApply] + pu_hat_square.GetCellByIdx(indexXToUpdate, indexYToUpdate));
                            psig_u_hat_square.SetCellByIdx(indexXToUpdate, indexYToUpdate,
                                                           pijCell[j + rangeToApply, i + rangeToApply] * sigUHatMatrix[j + rangeToApply, i + rangeToApply] + psig_u_hat_square.GetCellByIdx(indexXToUpdate, indexYToUpdate));
                            uhatGM.SetCellByIdx(indexXToUpdate, indexYToUpdate,
                                                (pu_hat.GetCellByIdx(indexXToUpdate, indexYToUpdate) / pij_sum.GetCellByIdx(indexXToUpdate, indexYToUpdate)));
                            normalisedPijSum.SetCellByIdx(indexXToUpdate, indexYToUpdate, pij_sum.GetCellByIdx(indexXToUpdate, indexYToUpdate) / laserHit.GetCellByIdx(indexXToUpdate, indexYToUpdate));
                            double largeU   = (pu_hat.GetCellByIdx(indexXToUpdate, indexYToUpdate) / pij_sum.GetCellByIdx(indexXToUpdate, indexYToUpdate));
                            double largeSig = (psig_u_hat_square.GetCellByIdx(indexXToUpdate, indexYToUpdate) + pu_hat_square.GetCellByIdx(indexXToUpdate, indexYToUpdate)) / pij_sum.GetCellByIdx(indexXToUpdate, indexYToUpdate) - largeU * largeU;

                            uhatGM.SetCellByIdx(indexXToUpdate, indexYToUpdate, largeU);
                            sigSqrGM.SetCellByIdx(indexXToUpdate, indexYToUpdate, largeSig);

                            Index index = new Index(indexXToUpdate, indexYToUpdate);
                            if (!indicesDictionary.ContainsKey(index))
                            {
                                indicesDictionary.Add(index, indicesDictionary.Count);
                            }

                            /*
                             * if (indicesDictionary.ContainsKey(index))
                             * {
                             *  int indexOfIndices = indicesDictionary[index];
                             *  heightList[indexOfIndices] = (float)largeU;
                             *  covList[indexOfIndices] = (float)largeSig;
                             *  pijSumList[indexOfIndices] = (float)pij_sum.GetCellByIdx(indexXToUpdate, indexYToUpdate);
                             * }
                             * else
                             * {
                             *  indicesDictionary.Add(index, indicesDictionary.Count);
                             *  indicesList.Add(new Index(indexXToUpdate, indexYToUpdate));
                             *  heightList.Add((float)largeU);
                             *  covList.Add((float)largeSig);
                             *  pijSumList.Add((float)pij_sum.GetCellByIdx(indexXToUpdate, indexYToUpdate));
                             * }
                             */
                        }
                    }
                    sw6.Stop();
                } // end foreach

                //Console.WriteLine("1: " + sw1.ElapsedMilliseconds +
                //                                    " 2: " + sw2.ElapsedMilliseconds +
                //                                    " 3: " + sw3.ElapsedMilliseconds +
                //                                    " 4: " + sw4.ElapsedMilliseconds +
                //                                    " 5: " + sw5.ElapsedMilliseconds +
                //                                    " 6: " + sw6.ElapsedMilliseconds +
                //                                    " TOTAL: " + (sw1.ElapsedMilliseconds + sw2.ElapsedMilliseconds + sw3.ElapsedMilliseconds + sw4.ElapsedMilliseconds + sw5.ElapsedMilliseconds + sw6.ElapsedMilliseconds).ToString());
            } // end function
        }