Omni-SLR: a compact, low-cost, and multi-purpose satellite laser ranging system

Abstract We present Omni-SLR, a compact and low-cost satellite laser ranging (SLR) system developed to explore the minimum configuration needed to achieve useful geodetic performance. The system was built almost entirely from commercially available components and designed for easy transport, low-power consumption, and single-photon operation. As of 2025, the total hardware cost excluding enclosure and labor is about 50–60 k USD/EUR. Despite its small size and modest link budget, the system has successfully achieved precise ranging to low Earth orbit satellites and even to the LAGEOS satellites, demonstrating the feasibility of meaningful SLR observations at only one or a few percent of the cost of conventional facilities. Tests at Ishioka confirmed stable operation, accurate system delay calibration, and SLR normal-point data quality comparable to other SLR stations. The project aims not only to expand SLR network coverage with affordable, transportable systems but also to enable time transfer and optical communication experiments.