Feasibility study of using retroreflective foils for satellite laser ranging

Abstract

This study is a research project for the use of retroreflective foils for satellite laser ranging and was developed in collaboration with the Institute of Technical Physics from the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt) in Stuttgart. Due to the continually increasing number of objects in Low Earth Orbit, space surveillance systems are becoming essential, while conventional utilized radar systems are limited in accuracy. To reduce the growing risk for satellite missions, satellite laser ranging Systems could contribute to more accurate position determination. The use of this technology urges satellite operators to implement passive optics in their payloads to enhance the optical cross section. This can be in conflict with dispenser systems [1]. Indeed, some stations may be able to range targets through only diffuse scattering. However, this requires high-power laser systems and consequently incurs high costs. The use of retroreflective foils leads to a more flexible implementation and could therefore make the use of satellite laser ranging more attractive. Also P. Sauer et al. [2] emphasizes the advantages of using retroreflective foils but has only ranged them in ground-based experiments over relatively short distances. Therefore, this study offers a detailed analysis of commercially available foils, accompanied by link budget calculations. Since the structure of retroreflective foils differs from that of conventionally used retroreflectors, certain assumptions must be made regarding a describtion of the far-field diffraction pattern, the peak optical cross section and the effective area including the retroreflective output aperture as a function of the incidence angle. Therefore both a theoretical and experimental examination will support these assumptions. The optical cross section of retroreflective foils will be calculated as a function of the embedded diameter, the reflectivity, and utilized area. In addition the required area and diameter will be calculated as a function of a given optical cross section.