Path: FormationFlying/Control
% Iterative impulsive maneuver delta-V
Computes the delta-v's required to implement a formation flying maneuver for a
single spacecraft. The desired relative state is iteratively recomputed,
bringing the desired state closer to the current state, until the largest
single delta-v in the maneuver is under the maximum limit.
A fixed thrust actuator is assumed when converting delta-v to burn duration.
Algorithms do not account for gravitational perturbations or disturbances.
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Usage:
[maneuver, foundSoln, resetGoals] = IterativeImpulsiveManeuver( 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, Alfriend format: [a,i,W,w,e,M]
- xH Measured relative state in Hills frame
- mass Spacecraft mass [kg]
- tM Timetag of measurement [sec]
goals (.) Geometric goals describing desired relative periodic 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)
- maxDeltaV Maximum delta-v
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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
foundSoln (1) Flag indicating whether a solution was found or not
resetGoals (1) Flag indicating whether the goals were reset or not
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