Huld s.r.o. and the University of West Bohemia in Pilsen have developed a new hardware and software platform capable of generating accurate and stable timing information with a high level of integrity and availability. The system merges multiple timing sources and detects inconsistencies among inputs.
The results of the European Space Agency-funded ‘Advanced Algorithms and Techniques for Resilient Time Provision’ project were presented at a special ESA-hosted event by Ondřej Daniel, System Engineer at Huld, and Jindřich Duník, Researcher at the University of West Bohemia.
The new system combines clock signals using multiple Kalman filters. Daniel said this combination provides better frequency stability and fault detection. Project partners implemented advanced methods such as dual mixer time difference (DMTD) and time-to-digital conversion (TDC) to achieve excellent precision measurements with resolutions down to 0.1 ps. The high-performance hardware platform utilizes ADCs, FPGAs, and Zynq UltraScale+ chips, with software for real-time visualization.
Tested and proven
The system underwent rigorous testing in 2024 at the ESA ESTEC Universal Time and Control (UTC) lab in Noordwijk, demonstrating high precision in time measurement, fault detection, and clock synchronization under a variety of conditions. Notably, an Allan deviation of 4 × 10⁻¹⁴ at 1 second was achieved, a metric rivaling commercial phase noise analyzers. Developed algorithms also proved capable of identifying frequency deviations at 10⁻¹³ and phase jumps as small as 5 ps, displaying the kind of sensitivity necessary for high-end applications.
The system, Daniel said, can run several clock combination algorithms in parallel while steering a high stability oscillator towards an ensemble. Supporting functions were also developed for the identification of noise characteristics. Future work will focus on refining the fault detection algorithms and improving the pulse per second (PPS) subsystem for more robust and reliable time provision in critical infrastructure applications. The current hardware will also be further iterated into fully integrated circuits.
Interestingly, while the system is commercially applicable now, especially in telecom and power grid timing, the project team does not intend to try to compete with existing high-end fiber-optic solutions, e.g. White Rabbit. Instead, it offers a niche resilience layer, especially valuable where GNSS-based synchronization signals might be spoofed, jammed, or otherwise compromised.
The project was funded under the ESA NAVISP program, Element 1, which supports innovation across the European PNT value chain.
