TimeTech GmbH Stuttgart, Germany is a privately owned company founded in 1990. It is the global leader in the design and manufacturing of satellite-based, high performance time-transfer equipment, as well as for precise frequency and time-interval measurement apparatus. TimeTech has commercialised the TWSTFT (Two Way Time and Frequency Transfer) method and technology, which was originally developed at the Technical University at Berlin in the late 1970s. Its applications include satellite ranging, precise orbit determination to cm level, and precise point positioning. Key National Metrology Institues (NMIs) use our products for comparison of national primary clocks in support of the generation of UTC by the BIPM, (Bureau International de Poids et Mesures) in Paris, with a time transfer uncertainty Ub well below 1 ns. This method allows for resilient, dependable time links also for commercial users, independent from GNSS-based solutions. TimeTech has pioneered time-transfer between space and ground at the sub-pico second level, which is in orbit on board the International Space Station (ISS) as part of ESA’s ACES mission.