초록 ▼

A method and apparatus are provided that effect spacecraft wheel desaturation by controlling the magnetic torquers aboard the spacecraft. An attitude control system energizes a magnetic torquer coil or set of magnetic torquer coils using a power source having an initial polarity and then monitors th

A method and apparatus are provided that effect spacecraft wheel desaturation by controlling the magnetic torquers aboard the spacecraft. An attitude control system energizes a magnetic torquer coil or set of magnetic torquer coils using a power source having an initial polarity and then monitors the spacecraft's response to the torque created by the coil's magnetic field. By measuring the spacecraft's response to the torque created by the energized magnetic torquers, the direction of the earth's magnetic field is determined. Once the direction of the earth's magnetic field is known, the proper polarity may be applied to the coil to achieve the desired torque. The control system of the present invention synchronously demodulates the craft's angular velocity, estimated from signals obtained from the attitude sensors, using a small dither signal that is superimposed on the control current used to energize the magnetic torquer coil. The result of the synchronous demodulation yields information as to the direction of the earth's field which is then used to control the polarity of the coil energizing power source. Thus, the magnetic torquers are used to achieve a torque that opposes the torque created by the reaction wheels to effect wheel desaturation without the need for the complex and weight-intensive magnetic field measuring and estimating equipment used in conventional attitude control systems.

대표청구항 ▼

[ What is claimed is:] [1.]1. An apparatus for use in connection with controlling the attitude of a spacecraft, the apparatus comprising:at least one magnetic torquer that, when energized, creates a torque that acts upon the spacecraft;at least one sensor that monitors at least one spacecraft variab

[ What is claimed is:] [1.]1. An apparatus for use in connection with controlling the attitude of a spacecraft, the apparatus comprising:at least one magnetic torquer that, when energized, creates a torque that acts upon the spacecraft;at least one sensor that monitors at least one spacecraft variable and generates sensor signals containing information about said at least one spacecraft variable; anda control device that applies a test signal to said magnetic torquer, evaluates said sensor signals to determine an impact of said test signal, and controls the operation of said magnetic torquer based on said evaluation of said sensor signals;whereby said test signal and evaluation of said sensor signals to determine an impact of said test signal is used to determine an estimate of the earth's magnetic field which is unknown prior to application of said test signal.