1. A method for calculating an expected maximum probability of detection of targets for a sensor grid within a detection zone for optimizing said sensor grid, comprising: providing a plurality of sensors in said sensor grid that produce sensor data for detection of said targets; partitioning said detection zone into a plurality of discrete voxels that form a discrete voxel detection zone grid comprising rows and columns wherein each discrete voxel comprises a discrete three-dimensional space; removing non-spatial variables from said sensor data of said plurality of sensors of said sensor grid to provide a sensor performance of said plurality of sensors as a function of spatial variables; mapping said sensor performance of said plurality of sensors into coordinates consistent with said discrete voxel detection zone grid; configuring a computer to provide selection options for selecting a discrete target flow model to represent target movement within said discrete voxel detection zone grid wherein said discrete target flow model comprises either a restricted stochastic movement model or an unrestricted stochastic movement model, said restricted stochastic movement model requiring forward movement of said targets from row to subsequent row from an entry point on a first row toward an exit point on a last row, said unrestricted stochastic movement model allowing forward and reverse movement of said targets between rows from said entry point to said exit point; configuring said computer for determining said expected maximum probability of detection of said targets for said sensor grid within said detection zone; and utilizing said expected maximum probability of detection for optimizing said sensor grid.