Centre for Research in Earth and Space Technology

Canadian Space Agency

The Institute for Space and Terrestrial Science

Thomson-csf Optronics Canada Inc.

Charles H Hersom

Allan B Hollinger

Zvika Afik

Paul J Thomas

Philip Patrick Duggan

William A Gault

Sun sensors or position sensors may be used to determine the angular location of the sun or other object with respect to the sensor. The sun sensor provides high resolution over a wide field of regard. A position or sun sensor comprises a sensor housing, a plurality of pinholes formed In the sensor housing, a detector mounted within the housing and a method of processing the information detected. The detector is mounted in the sensor housing. Each pinhole has a field of view and the detector receives the images from each field of view. Each field of view is defined by the position of the pinhole relative to the detector. The images are received in an overlay relationship thereby providing a field of regard. The processing method determines the presence and location of an object In a field of regard.

Sun sensors using multi-pinhole overlays

The present invention provides a method for distinguishing a boundary of an object, and the object itself, from its background. In the method electromagnetic radiation is detected from at least one field of view substantially spanning the boundary of the object and background adjacent to the boundary and superimposed or overlaid as images onto a detector. The method includes correlating spatial transitions in intensity of the overlaid images on the detector with a boundary of the object. When used for determining the attitude of a satellite with respect to the earth, the detector is a thermal infrared detector thereby providing a sharp contrast between the thermal emission of the earth and cold space. The invention provides a simple, effective method and device for determining satellite orientation and/or attitude with respect to a thermal infrared-emitting target body. The sensor includes a segmented limb-looking mirror to provide multiple fields-of-view within the field-of-regard and superimposing these fields-of-view as images onto a common detector. The required resolution can be obtained while providing a wide range of operational orbital altitudes. The attitude of the satellite can vary by a large angle from the minimal orientation while still permitting an accurate determination of attitude. Multiple channels in a modular form provide redundancy, improved accuracy, and the opportunity of providing more diverse configurations. The utilization of uncooled microbolometer arrays as imaging detectors removes the requirement for additional cooling equipment thereby providing a low cost, small size and low mass sensor with configurational flexibility and no moving parts.

Satellite attitude sensor using thermal imaging

The present invention provides a method for distinguishing a boundary of an object, and the object itself, from its background. In the method electromagnetic radiation is detected from at least two fields of view substantially spanning the boundary of the object and background adjacent to the boundary and superimposed or overlaid as images onto a detector. The method includes correlating spatial transitions in intensity of the overlaid images on the detector with a boundary of the object. When used for determining the attitude of a satellite with respect to the earth, the detector is a thermal infrared detector thereby providing a sharp contrast between the thermal emission of the earth and cold space. The invention provides a simple, effective method and device for determining satellite orientation and/or attitude with respect to a thermal infrared-emitting target body. The sensor includes a segmented limb-looking mirror to provide multiple fields-of-view within the field-of-regard and superimposing these fields-of-view as images onto a common detector. The required resolution can be obtained while providing a wide range of operational orbital altitudes. Multiple channels in a modular form provide redundancy, improved accuracy, and the opportunity of providing more diverse configurations. The utilization of uncooled microbolometer arrays as imaging detectors removes the requirement for additional cooling equipment thereby providing a low cost, small size and low mass sensor with configurational flexibility.

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Toronto, Canada

Charles H Hersom