Method and apparatus to determine a planet vector
AssigneeOerlikon Space AG
InventorsEdoardo Charbon, Renato Krpoun, Noemy Scheidegger, Herbert Shea
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Abstract
The present invention relates to a method for a low cost Planet vector Sensor based on imaging atmospheric oxygen emission at 762 nm or at 557.7 wavelengths using either CMOS, CCD or arrays of single photon avalanche diodes (SPADs). In both daytime and night time, there is continuous emission at 762 nm wavelength due to atomic oxygen recombination or excitation. Even if the emission at the limbs is 100 times stronger in the day than at night, there is ample unambiguous signal for the operation of the sensor according to the present invention using this wavelength if measured with an appropriate detector and an adapted algorithm to determine the Planet vector.
Claims13
A method to determine the Planet vector from a point remote from the Planet by a detection of visible or near visible light, comprising the steps:
- imaging of the Planet to provide corresponding image data,
- acquisition of at least two points of the limb of the Planet
- processing the image data, and
- determining the Planet vector,
- characterized in that,
- said imaging of the Planet is an imaging of atmospheric gas emission of the Planet and the step of determining the Planet vector further comprises the steps:
- calculating the radius of a theoretical circle on an image obtained by the imaging corresponding to a maximum of the atmospheric gas emission, and
- finding the best correlation between the atmospheric gas emission obtained by the imaging and said theoretical circle.
A system for determining the Planet vector from a point remote from the Planet comprising:
- an optical system;
- a detector, and
- an electronic circuit
- wherein said optical system receives and guides visible or near visible light received from the atmosphere of said Planet to said detector, and
- wherein said electronic circuit processes image data provided by the detector.
Dependencies are inferred from the claim text.