Laboratory Test System for Performance Evaluation of Advanced Star Sensors

Latest generation star sensors are characterized by innovative features that need additional testing capability in comparison to previous star trackers, therefore novel indoor test facilities are required in some cases to assess their performance. This paper reports on design, realization and operation of such a laboratory system. It is based on simulation of star field scenes, to be acquired by the sensor under test. The scenes are generated on a 21” high-resolution cathode ray tube display by means of a simulation software running on a personal computer. Selected components are commercial, off-the-shelf products, hence offering low cost and short time development. Results of a study conducted to identify performance of an advanced star sensor are reported in detail. A satisfactory accuracy, 35 arcsec, is achieved for pitch and yaw pointing angles. Adequate results have been attained also for the corresponding rates: 230 arcsec/s during slow rotations, and 10% of the maximum angular rate during fast ones. These values are adequate for most spacecraft operating conditions. Larger uncertainties are attained for roll rotations: in the range of 70 - 420 arcsec for angle and of 1000 - 1750 arcsec/s for angular rate measurements. Consequently, roll values are acceptable only for fast rotations and medium or low accuracy operations.