Image Based Attitude Determination Using an Optical Correlator

Abstract

The paper discusses a spacecraft attitude determination system based on image data provided by an onboard observation camera. The attitude is measured by the observed image motion which can be registered by an appropriate allocation of additional navigational area sensors in the focal plane of the onboard imaging system. An advantageous feature of this concept is the possibility to use the payload observation camera without changes in the optics as attitude sensor. The real-time image processing is performed by a hybrid opto-electronic system based on a Joint Transform Optical Correlator. With up to-date opto-electronic components the correlator can have a size of 20x40x220 mm, a mass within 0.5 kg and a power consumption less than 5 W. The paper presents a system layout of a laboratory prototype and gives the performance estimations in terms of data processing rate, accuracy, sensitivity to noise and distortions and response time under disturbing conditions.