Runs the collision monitoring algorithm. Checks the ellipsoids for self
   and a neighboring spacecraft. Self "position measurement" should be 
   [0;0;0;0;0;0] at each time if relative measurements are used. Includes
   options for continuous and discrete ellipsoid propagation for circular
   and low-eccentricity reference orbits. All propagation is performed in
   Hill's frame. Assumes that no maneuvers are taking place.

   Since version 7.
   [prob, d, xhat, Shat] = CollisionMonitor( action, d, jD, y );

   action  (:)    'initialize' or 'run'
   d        :     Data structure
                  .hRef          Altitude of the reference orbit (km)
                  .eRef          Eccentricity
                  .dR            Reference length of Hill's orbit (km)
                  .initBounds    Error in measurement
                  .nSC           Number of S/C 
                  .predictTime   Total amount of time to predict for
                  .nSampleTimes  Number of points in predictTime
                  .scalev        Sigma for measurement noise
                  .discrete      Flag for method type
                  .mSC           Spacecraft mass (kg)
                  .lenSC         Spacecraft length (m)
                  .diaSC         Spacecraft diameter (m)
                  .Cd            Drag coefficient
                  .Cr            Reflectivity of s/c: 0.0 for translucent; 
                                   1.0 for black-body; 2.0 for flat mirror
   jD      (1)    Epoch in Julian date
   y       (6,:)  spacecraft current position in Hill's frame

   prob   (n)         probability of collision    
   d      (n)         minimum distance between spacecraft position ellipsoids
   xhat   (6,n,2)     xhat, ellipsoid centers, for both spacecraft
   Shat   (6,6,n,2)   Shat, ellipsoid size matrices, for both spacecraft


Common: Database/Constant
Common: Time/JD2000
FormationFlying: Collision/CollProbSet
FormationFlying: Collision/DistantPtToEll
FormationFlying: Collision/EllipsePropCirc
FormationFlying: Collision/MinDEllipsoid
FormationFlying: Collision/WorstCasePerturbations
FormationFlying: EccDynamics/FFEccLinOrb
Math: Linear/Mag
OrbitMiniToolbox: Support/M2Nu
SC: BasicOrbit/OrbRate
SC: BasicOrbit/Period