A Design and Implementation of an IP Over USLP Ground Gateway System

With the advancement of satellite communication technology, space links are no longer limited to telemetry, telecommand, and remote sensing data transmission but are increasingly required to support a variety of user services. However, the significant differences between ground and space link protocols hinder data exchange. To address this challenge, the Consultative Committee for Space Data Systems (CCSDS) introduced the Unified Space Data Link Protocol (USLP) to enable the compatibility of IP-based services with space link protocols. However, current research on IP over CCSDS is limited to the implementation of CCSDS protocol standards on space-toground and inter-satellite links, without addressing the conversion between ground protocol stack data, and space protocol stack data. To address this issue, we propose a ground gateway system for IP over USLP, which enables bidirectional conversion between ground link-layer protocols and space link-layer protocols. The conversion process is fully transparent to both users and satellites and supports high link rates. The system has been deployed as part of a ground test gateway for an operational satellite, allowing ground users to conduct in-orbit testing of various services. Experimental results demonstrate that the gateway effectively performs protocol conversion without requiring any modifications from users, thereby facilitating broader adoption of IP-based services in satellite networks.