Mirrors Could Tell a Laser Station Which Satellite It Is Tracking

Researchers at two Chinese Academy of Sciences observatories have proposed a way for a single laser ranging station on the ground to read a satellite's identity and its orientation at the same time, with nothing aboard the spacecraft but an arrangement of passive mirrors. The work appeared Sept. 19, 2026 in the journal Communications Engineering.

The paper sets the problem in space traffic management: as satellites are built in batches and flown in dense groups, telling one from another, and knowing which way each is pointing, gets harder. Ground stations already time a laser pulse out to a satellite and back, and get the distance with high accuracy. This method would have one of those stations come away with two things a distance measurement on its own cannot give it.

The idea is to make the mirrors do two jobs. Corner cube reflectors, prisms that send a beam straight back the way it came, are set out in an L, and that pattern is treated as both an identification code and a set of baselines, the fixed separations between the mirrors. Identity and orientation are then worked out from the differences between the ranges measured to each reflector. Kai Tang of the Shanghai Astronomical Observatory, Chen Song of the Purple Mountain Observatory and colleagues describe the scheme in Communications Engineering.

Theoretical analysis and numerical simulations validate the performance of the proposed L-shaped layout, the authors report, and field experiments further verify its feasibility.

Reflectors of this kind are passive and need no power of their own, which the paper credits with light weight and long life.