Orbit determination and time synchronization in real-time using Galileo HAS: The HAUT-S satellite payload

Kurzfassung

Nowadays, for many missions in low Earth orbit (LEO) such as positioning, navigation and timing (PNT) services or Earth observation precise knowledge of a satellite's position in real-time is a crucial requirement. Consequently, the demand and for precise orbit determination and time synchronization (ODTS) payloads operating as autonomous onboard systems is growing. DLR and Spaceopal are currently conducting the development and verification of the HAUT-S payload, which aims to offer a lean and flexible real-time ODTS solution. HAUT-S only requires GNSS signals for an autonomous operation, and employs Galileo High Accuracy Service (HAS) corrections to further improve performance. The hardware consists of commercial off-the-shelf (COTS) components and is designed with flexibility and scalability in mind. With a low size, weight and power (SWaP), the requirements on the host satellite bus are minimized, and integration can also be realized on small satellites. The proven real-time navigation filter is able to achieve decimeter level orbit determination performance, and the optional time synchronization module has already been demonstrated to offer a low to sub nanosecond precision with respect to a GNSS time scale. This paper presents the current status of the design and development of the HAUT-S payload, highlighting the hardware and firmware design aspects, and demonstrates the initial orbit determination performance of the navigation filter using real observation from two different LEO satellites.