Satellite License Plate: passive and compact optical spectrally-based identification method for satellites

Satellite identification and tracking is fundamental for decision making in space traffic management. Cooperative optical identification methods enlarge the toolbox of identification techniques which currently count on radar and passive optical observations. Here we present a cooperative method to identify satellites from the ground by means of laser techniques: the Satellite License Plate (SLP). SLP employs unique spectrally-encoded retroreflecting tags mounted on the satellite. The interrogation of the tags could be performed with laser enabled optical ground stations. The benefit of the concept is that the tag concept is fully passive, minimally invasive, and scalable from tens to hundreds of unique combinations, allowing to map a large number of satellites on a single orbit. The SLP method is here described by means of end-to-end theoretical analyses on the final performance of identification and experimental results gathered during km-range ground-to-ground free space tests. A research team from the High-Tech Industry Unit at TNO reports a method to identify satellites using retroreflecting tags with spectral signatures mounted on these satellites. The approach reduces the complexity of the observation system and does not require any power sources on board.