Staring horizon sensor
OwnerRobert C. Savocainventor
Life of this patent
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Abstract
A staring horizon sensor is mounted on an orbiting satellite has one or more linear infrared detector arrays having the horizon being detected imaged thereon. The arrays are each connected in cyclic repetitive alternating polarity patterns for generating at least two output signals which are offset in phase. The output signals are processed to locate the position of the horizon on the arrays. The repetitive pattern interconnection of the elements in the arrays provide a focal plane data compression which reduces the bandwidth as well as the complexity of the processing electronics. In addition, interconnecting the detective elements in repetitive alternating polarity groups having a spatial frequency greater than the spatial frequency of the thermal variation of the horizon minimize any error due to the earth's thermal variations.
Claims9
A staring horizon sensor having at least one telescope means mounted in an orbiting satellite having infrared detector means on which the horizon to be detected is imaged thereon by said telescope means;
- said infrared detector means comprising at least a first linear array of infrared detectors;
- means for connecting said infrared detectors in repetitive cycles of alternating polarity periodic patterns for providing output signals from said linear array in which output signals are periodically offset in quadrature;
- and
- quadrature detector means coupled to said infrared detectors for determining the position of said horizon on said linear array of infrared detectors.
A method of determining the attitude of a spacecraft using a staring array horizon sensor the steps of:
- imaging the horizon on a first linear array of infrared detector means;
- interconnecting the elements of the linear array infrared detector means in repetitive, cyclic alternating polarity patterns;
- offsetting the phase of said repetitive patterns of infrared detector elements;
- deriving signal outputs from said patterns of infrared detector elements;
- and
- quadrature detecting said signal outputs to determine the position of the spacecraft with respect to the horizon.
The method of determining the attitude of a satellite orbiting the earth using a horizon sensor mounted on the satellite;
- imaging the horizon on at least one linear array of infrared detector means,
- deriving a first repetitive signal from predetermined groups of interconnected, individual detector elements in said infrared detector means;
- deriving a second repetitive signal from different predetermined groups of interconnected individual detector elements in said infrared detector means, shifted in phase from said first repetitive signal;
- and
- using said first and second repetitive signals in the determination of the position of the horizon with respect to said infrared detector means.
Dependencies are inferred from the claim text.