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Session A10: Complementary PNT: PNT from LEO 2

Satellite Network-Distributed Position and Timing Processing for Robust, Resilient PNT in GPS-Denied Environments
Joseph Strus, Kalia Crowder, Steve Dawson, Cory Albright, Victor Aguero, Kyle Leveque, and Simon Lee, Cambrian Works, Inc.
Location: Ballroom B
Date/Time: Wednesday, Jun. 4, 2:10 p.m.

Cambrian Works is developing a robust, distributed orbit and timing application that provides autonomous payload synchronization and orbit estimation across a pLEO constellation, providing GPS-level accuracy in GPS-denied environments. This application supports local clock estimation, synchronization, and payload distribution of clock signals. Most importantly, the application supports both single satellite as well as cluster-wide estimation modes. Coupled with Cambrian network management and routing, the application provides enhanced accuracy, resiliency, and autonomy as data processing can be centralized at any node in the cluster.
Cambrian Works is a Silicon Valley startup established in 2020 to develop advanced infrastructure and technologies for space navigation, networking, and operations for government and commercial customers. The Cambrian application runs on commercial, off-the-shelf (COTS) hardware as an orbit and timing application overlaying the network layer for space-based constellations. The application takes advantage of the optical and/or RF links across networked constellations to provide clock accuracy that can be precise and synchronized at better-than-GPS levels even in the absence of GPS and without the large size, weight, power, and cost of very accurate clocks.
The current Cambrian prototypes use emulation and sensor models as software surrogates to drive high performance non-linear orbit and clock estimators in either single satellite or cluster-wide mode. A feature of the product is to minimize solution latency as the cluster size increases while maintaining the highest levels of PNT performance. The application leverages an optional separate hardware timing board to provide a common disciplined, bus and sensor time reference that is portable across different vendor bus configurations. The hardware modules support multiple types of COTS clock hardware to accommodate various PNT performance and cost solutions.
The application additionally can be run in an offline mode for performance assessment and validation. This allows for simplified analysis of optimal update and constellation PNT performance without the additional complexity of full clock hardware in the loop. The offline mode is particularly useful for trade space analysis regarding measurement rates, cluster size and network and system latencies.
Realistic evaluation of architecture performance is performed via Cambrian’s cloud-based constellation digital twin emulation tool (Plexus) and constellation digital twin visualization tool (Retina). Retina allows the visualization of traffic analysis, routing and re-routing, and resource utilization with various space-based communications networks. The results are realistic since the Plexus tool emulates traffic flows using actual network routing code at each represented node in the constellation and imposes realistic physics for the links – enabling only real links, not impossible links between nodes. The network emulation demonstrates the resilient flow of traffic and PNT messages, allowing the analysis and visualization of PNT accuracy across a cluster and globally throughout the constellation.
The presentation will include testing and performance results pending government approval.

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