Network Assisted PNT in GPS Denial

Technical Objectives: leverage prior R&D  (Army/DoD initiatives as well as internal esc Aerospace) to enable the Warfighter to maintain accurate PNT (acquisition/tracking) while operating in low RF signal power environments (under tree canopy, vehicles, buildings, and other RF challenged areas). This will be accomplished through: Leveraging esc Aerospace base product (escPNTTM) - already proven to provide positional accuracy in GPS challenged/denied Centimeter accuracy in GPS “challenged” environments Resilient PNT in total GPS denied environments (currently under development, see AFLCMC SBIR) Integration with Android Tactical Assault Kit (ATAK) demonstrated as part of ongoing AFLCMC SBIR. Additional demonstrations will be conducted with regard to the integration with Joint Battle Command-Platform (JBC-P) and Nett Warrior Provide a low Size, Weight, Power and Cost (SWaP-C) product to support Warfighter needs in dismounted application (current product <6 oz, 3” × 4”, ~6 W) Add network assisted PNT capability - time transfer to provide additional PNT resilience/accuracy Minimizes load on existing network Meets all security requirements Ensures efficient data transport/storage Minimizes time to first fix (TTFF) in order to maximize utility of solution at “startup” Leverages current comms/network devices/capability Technical Approach Unlike prior research that focused on a “base-station” to enable Network assisted PNT, our approach is based on the concept that each node in the network has the ability to act as the “base-station.” That is, at least one node in the network will have a “Trusted” PNT (accurate and reliable) time/position. In this sense, any node in the network has the ability to be the “base-station” (what we call, the “Trusted Node”). All other nodes in the network will be “synchronized” to that Trusted Node, thereby enabling all nodes in the network to maintain accurate position/time. Terminology/Basic Concept: “Trusted Node”: One or more nodes in the network that has a well-established, reliable PNT (established if the node remains stationary at a known position and/or is receiving reliable GPS signals) Any node can be a Trusted Node. “Trusted PNT”: any node that has a reliable/accurate PNT by being a Trusted Node, or by synchronizing PNT with some other node(s) with Trusted PNT. The PNT error/uncertainty is reduced by increasing the number of synchronizations between nodes with Trusted PNT. At the core of all PNT is precise timing. Often, this can be provided by a GPS-disciplined rubidium clock, but GPS synchronization will not be available under GPS denial, so alternative methods need to be created. To prevent the inevitable drift between two unsynchronized clock sources, and guarantee accuracy of the positioning estimate, esc Aerospace will implement a Remote Synchronization Protocol (RSPTM) for between a node with lost Trusted PNT and a node with Trusted PNT.