A novel two-axis earth horizon sensor

The Surrey Space Centre is developing a low-cost infra-red sensor, based on a commercially available system. The paper covers the selection criteria used in choosing a commercially available sensor from the wide range of available system on the market. The resulting selection, a 16x 16 pixel pyroelectric array, is based on a hand held system which has many common requirements with a space based system. The use of a 2-d array allows more information to be retrieved from a single optical head. Each sensor will be capable of providing high resolution pitch and lower resolution roll angles. When placed orthogonally, two such sensors can be used in a higher accuracy system which also provides 'graceful degradation' should an optical head fail.