Rapid tactical deployment capability of a transportable optical ground station.

In this paper we present TeraNet-3 (TN-3), a transportable optical ground station (TOGS) comprising the third node of the TeraNet optical ground station network in development by the University of Western Australia (UWA). In an effort to improve on the versatility granted by existing TOGS systems, TN-3 is capable of rapid and precise star-based calibration in daytime conditions in the absence of stability hardware. By using a consumer-grade inertial measurement unit and dual camera system, the TOGS can be deployed and ready for free space optical communications (FSOC) to low Earth orbit (LEO) within 5-10 minutes from arrival on-site. In testing the system has demonstrated on-sky root mean square (RMS) pointing errors of 3.54 arcseconds (17.2  rad) and a mean RMS closed-loop tracking error of 1.14 arcseconds (5.54  rad) across multiple LEO satellite passes. By eliminating the need for site-specific requirements like external power or level terrain, the design of TN-3 facilitates flexible deployment in remote locations. These capabilities introduce a range of novel 'tactical deployment' scenarios, such as rapidly re-establishing communications in disaster-affected areas, communications operations in contested or GPS-denied environments, disrupting adversarial quantum communications, and utilizing the system's 17-inch telescope for strategic space situational awareness observations. The versatility of the system is further bolstered by direct compatibility with UWA's existing pointing, acquisition, and tracking systems for FSOC links to land-, air-, and sea-based targets. Together, these capabilities greatly extend the operational versatility granted by existing TOGS systems.