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A technique for maintaining a satellite in an assigned orbit without control or intervention from the ground. Autonomously obtained navigational data provide a measurement of the actual orbit in which the satellite is traveling. So long as the measured orbit conforms to a desired orbit to within a p

A technique for maintaining a satellite in an assigned orbit without control or intervention from the ground. Autonomously obtained navigational data provide a measurement of the actual orbit in which the satellite is traveling. So long as the measured orbit conforms to a desired orbit to within a preselected tolerance, periodic corrections of equal magnitude are made to the satellite\s velocity, based on a prediction of the effect of atmospheric drag on the orbit. Measurement of the orbit is made by observation of the time that the satellite passes a reference point in the orbit, such as by crossing the ascending node. If the measured orbit departs from the desired orbit by more than the preselected tolerance, a velocity correction of a magnitude different from the one based on prediction is applied to the satellite. For a decaying orbit, the magnitude of the velocity correction is increased above the correction value based on prediction. For a rising orbit, the magnitude of the velocity correction is decreased below the value based on prediction, and may be reduced to zero, allowing atmospheric drag to bring the measured orbit back within the preselected tolerance range.

대표청구항 ▼

A control system for autonomously maintaining an earth-orbiting satellite in a desired orbit, the system comprising: means located on the satellite for sensing successive positions of the satellite in its orbit and determining from the successive positions the actual orbit of the satellite; orbit co

A control system for autonomously maintaining an earth-orbiting satellite in a desired orbit, the system comprising: means located on the satellite for sensing successive positions of the satellite in its orbit and determining from the successive positions the actual orbit of the satellite; orbit correction computation means, also located on the satellite, for periodically computing an orbital velocity correction by comparing the determined actual orbit of the satellite to a desired orbit; means for converting the computed orbital velocity correction into a thruster signal to be applied to the satellite; and means for applying the thruster signal to thrusters located on the satellite, to effect an incremental orbital velocity correction.