초록 ▼

An earth sensor for use in orbiting satellites over an altitude range between low earth orbit (LEO) and geosynchronous orbit (GEO) and beyond employs a combination of both visible wavelength senor technology and infrared (IR) sensor technology to result in high accuracy capability. During the vast m

An earth sensor for use in orbiting satellites over an altitude range between low earth orbit (LEO) and geosynchronous orbit (GEO) and beyond employs a combination of both visible wavelength senor technology and infrared (IR) sensor technology to result in high accuracy capability. During the vast majority of an orbit of the satellite, the sensor is operating in the visible region using reflected sunlight from the earth horizon. During the relatively small time period of the orbit when the sun is behind the earth and it is not possible to operate the sensor in the visible region, precise attitude information is generated by earth radiance balance operating in the IR region. The sensor therefore exhibits the known advantages and accuracy of operation in the visible region for a major portion of an orbit of a satellite, but also maintains attitude control of the satellite during a relatively small portion of the orbit when operation in the visible region is not possible.

대표청구항 ▼

An earth horizon sensor for spacecraft orbiting the earth, said sensor comprising: first visible wavelength sensing means, second non-visible wavelength sensing means operatively associated with said first visible wavelength sensing means, and means for selectively controlling the respective operati

An earth horizon sensor for spacecraft orbiting the earth, said sensor comprising: first visible wavelength sensing means, second non-visible wavelength sensing means operatively associated with said first visible wavelength sensing means, and means for selectively controlling the respective operating states of said first and second sensing means such that the attitude of said spacecraft is controlled by said first visible wavelength sensing means during portions of the orbit during which the earth is sun illuminated and the attitude of said spacecraft is controlled by said second non-visible wavelength sensing means during portions of the orbit during which the earth is not sun illuminated.