Introduction

Docking between spacecraft requires precise relative navigation. Retro-reflectors may be used to indicate the position of fixed points on one of the vehicles for pose estimation. Advanced Optical Systems, Inc. (AOS) created corner cube targets for use with the Advanced Video Guidance Sensor (AVGS) on the Orbital Express mission.
   

Concept

Special optical design features are required to permit use of multiple target sets, enabling successful tracking over a 1 to 200 meter effective range.  AVGS as currently designed uses retro-reflecting targets that are placed in a specific geometry. By imaging the targets, AVGS is able to determine the targets’ range, bearing, and orientation. AVGS performance in part depends on the target’s spacing, cluster geometry, and corner cube aperture.

The final target design comprises a corner cube, filter glass, and a negative lens. The internal optical design of a single target is depicted here, along with the structure of the short-range target cluster. Targets are then grouped into clusters, each cluster comprising four targets. Multiple target clusters can be built for short, medium, and (if necessary) long-range performance.

Implementation

AOS has the necessary capability and experience to produce space qualified retro-reflector targets. We can work from mission requirements to develop appropriate designs, taking into account factors such as optical performance, laser power, target geometry, operating range, target manufacturability, and anticipated mission life.  We can conduct ground testing, performance analysis, and system integration.
   

For more information contact:

Stephen Granade
rotorcraft@aos-inc.com