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   Computes the delta-v sequence for a relative orbit maneuver. 

   A fixed thrust actuator is assumed when converting delta-v to burn duration.
   Algorithms do not account for gravitational perturbations or disturbances.
   The reference orbit may be circular or eccentric.
   The linear program "Simplex" is used to compute the delta-v sequence.
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   Format:
   [maneuver,maxDV] = ImpulsiveLPManeuver( state, goals, window, parameters );
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   Inputs
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   state             (.)  Data structure of the orbit state with following fields
                          - el           Measured mean orbital elements of reference
                          - xH           Measured Hills-frame state: [x;y;z;xdot;ydot;zdot]
                          - mass         Spacecraft mass             [kg]
                          - tM           Timetag of measurement      [sec]

   goals             (.)  Data structure of geometric goal information.
                          Describes the desired trajectory.

   window            (.)  Data structure of commanded time window with following fields
                          - startTime       Earliest possible start time                    [sec since 1970]
                          - nOrbMin         Minimum number of orbits maneuver may last      [orbits]
                          - nOrbMax         Maximum number of orbits maneuver may last      [orbits]
                          - nManeuvers      Number of maneuvers to search over
                          - timeWeightExp   Time-weighting exponent (greater than 0)

   parameters        (.)  Data structure of planning parameters with following fields
                          - fNom         Nominal Thruster force                             [kN]
                          - dTMax        Maximum allowable burn duration                    [sec]
                          - horizon      Minimum time between planning and first burn       [sec]
                          - tDelayOOP    Minimum time between final IP burn and OOP burn    [sec]
                          - nSPOCoarse   Number of samples per orbit for LP (coarse computation)
                          - nSPOFine     Number of samples per orbit for LP (fine computation)

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   Outputs
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   maneuver          (.)  Maneuver data structure with following fields
                          - t0           Earliest burn start time
                          - tF           Latest burn finish time
                          - nBurns       Number of burns required
                          + burnData[]   Array of burn data structures with following fields
                             - t   Burn start time   [sec since 1970]
                             - dT  Burn duration     [sec]
                             - dV  Delta-V           [km/s]
                             - uX  unit x Hills direction 
                             - uY  unit y Hills direction
                             - uZ  unit z Hills direction

   maxDV             (1)  The maximum delta-v of the sequence
   
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