A LATERAL SENSOR FOR THE ALIGNMENT OF TWO FORMATION-FLYING

The coarse lateral sensor is a system able to measure the lateral position
between two satellites. It bridges the gap between the alignment accuracy achieved
with the radio frequency metrology, and the alignment accuracy required the highprecision
optical metrology (fine-lateral and longitudinal sensor). The coarse lateral
sensor developed at Centre Spatial de Liège (CSL) is a standalone unit. Once
connected to an unregulated 28V power-supply, it delivers, the lateral position of a
corner cube retro-reflector (within an angle of 10 arcdeg and from 25 to 250 m) and
tracks this position at a rate of 10 Hz. The system is operational with the sun in its fieldof-
view. Real time centroidisation algorithms allow tracking the image position and feed
the on-board computer with this information via a RS422 link, allowing further position
stabilization. The coarse lateral sensor has successfully undergone thermal qualification
(40°C and -30 °C), and vibration test (high-level sinus, random and shock test in the 3–
axis).