Method, system and apparatus for spacecraft attitude control error reduction in trajectory interpolation
AssigneeThe Government of the United States of America, as represented by the Secretary of the Navy
InventorsRoberto Cristi, Joshua Levitas, Mark Karpenko
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Abstract
A method, apparatus and system for controlling an attitude of a spacecraft, the spacecraft including an attitude control system operatively associated with a ground-based spacecraft control system. According to an exemplary embodiment, the spacecraft attitude control system uses a B-spline interpolator for commanding the spacecraft and a Kalman filtering process is used to estimate B-spline interpolator coefficients. The methods and systems disclosed herein can be implemented in, for example, executable machine code and/or integrated circuit hardware.
Claims20
A method for controlling an attitude of a spacecraft, the method comprising:
- obtaining, by a ground-based spacecraft control system, an attitude trajectory of the spacecraft, wherein the ground-based spacecraft control system is operatively associated with a spacecraft attitude control system;
- down sampling, by the ground-based spacecraft control system, the attitude trajectory and using a Kalman filtering process to determine a state space implementation of spline coefficients for time-tagged spacecraft commands;
- transmitting, by the ground-based spacecraft control system, the time-tagged spacecraft commands to the spacecraft after processing the down sampled attitude trajectory;
- applying, by the spacecraft attitude control system, a B-spline interpolation filter to a sequence of down-sampled attitude trajectory points to determine a set of interpolated spacecraft commands at an arbitrary upsampling rate;
- reconstructing, by the spacecraft attitude control system, a time varying attitude command trajectory by applying a rectangular pulse zero order hold (ZOH) function;
- and
- modifying, by the spacecraft attitude control system, an attitude of the spacecraft based on the interpolated spacecraft commands.
A vehicle guidance system for implementing attitude control of a vehicle, comprising:
- a command reduction module for generating a reduced data set corresponding to a time-varying attitude command trajectory for a vehicle;
- wherein the command reduction module circuitry is configured to receive at least one time-varying attitude command;
- wherein the time-varying attitude command trajectory defines an attitude of the vehicle;
- and reduces the at least one time-varying attitude command trajectory into a vector of B-spline polynomial coefficients using a Kalman filtering process and smoothing process;
- and
- a command reconstruction module for generating data corresponding to the time varying attitude command trajectory;
- wherein the command reconstruction module is configured to receive the vector of B-spline polynomial coefficients;
- and reconstruct at least one time-varying attitude command trajectory by utilizing the vector of B-spline polynomial coefficients to perform a B-spline interpolation operation, and apply a zero order hold (ZOH) function.
A method for implementing attitude control of a vehicle, comprising:
- receiving, at a remote location from the vehicle data corresponding to at least one time-varying attitude command trajectory defining an attitude of the vehicle;
- processing, at the remote location, the at least one time-varying attitude command trajectory using a Kalman filter to determine a state space implementation of spline coefficients and generate a down sampled attitude command trajectory including a vector of B-spline polynomial coefficients;
- communicating, at the remote location, the down sampled attitude command trajectory to the vehicle;
- and
- modifying, by the vehicle, an attitude of the vehicle based on the down sampled attitude command trajectory and an interpolation filter operatively associated with the vehicle, wherein the interpolation filter is a B-spline interpolation filter applied to a zero order hold (ZOH) function.
Dependencies are inferred from the claim text.