Case study
SERGEANT Modernized CBA
The rationale, architecture, and component mapping behind SERGEANT as a modernized software-defined alternative to purpose-built navigation ASICs.
The problem
US Army Precision Guided Munitions face highly complex and rapidly advancing Navigation Warfare (NAVWAR) contested environments. At the same time, Assured PNT technology faces a supply-side risk: obsolescence of the first generation of purpose-built navigation ASICs, combined with the development timelines of their successors, increases the risk of production gaps for critical PGM programs.
Addressing that gap demands Assured PNT technology that is modular, flexible, and upgradable, and that leans on commercial off-the-shelf (COTS) components rather than purpose-built ASICs. Modularity and flexibility track the threat environment; COTS reliance directly mitigates future obsolescence.
The approach
SERGEANT pairs a software framework with MAGNOM — a COTS-based, modular hardware architecture. The framework is deliberately structured so that processing, logic, and RF cores can be refreshed independently without affecting the application software. The result is a receiver whose upgrade path is explicit, documented, and open to third-party integrators.
An open-systems foundation with documented module interfaces gives JPEO A&A the ability to replace modules and plug in third-party applications — mitigating vendor lock and keeping the future upgrade path unconstrained.
Base component mapping
The core RF-to-PVT processing chain. Each base component is mapped to a single, well-defined responsibility.
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Channel Controller (cc)
detail →Creates and manages processing channels for signals received from the RF front end. Acquires and tracks signals, decodes telemetry, and writes channel measurements to the Channel Measurement Table. Controls the correlators implemented in programmable logic and distributes tasks across CPU cores and FPGA fabric to exploit the MPSoC's heterogeneous architecture.
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Environment Manager (em)
detail →Controls the RF front-end chain: gain controllers, direct-conversion tuners, LPF/BPF/HPF filters, and variable-rate decimators. Runs anti-jamming algorithms to protect the receiver from intentional interference. Maintains the RFChain abstraction — the set of controllable components in a single chain — and exposes an API for the Channel Controller and other components to configure gain, filter, and decimation state per RF stream.
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Satellite Manager (sm)
detail →Owns all satellite-state information used by the PVT Provider to compute position and time. Stores orbital parameters for each satellite and provides the context needed to apply corrections to raw measurements — ephemeris, almanac, and ionospheric/tropospheric correction context.
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PVT Provider (pp)
detail →Computes the position, velocity, and time (PVT) solution from Satellite Manager measurements. Estimates satellite locations from ephemeris or almanac data, runs integrity algorithms (RAIM) to detect and mitigate faulty measurements, and can compute the solution using Ordinary Least Squares or a Kalman Filter depending on application configuration.
Outcomes
- A navigation receiver that survives ASIC obsolescence cycles by design.
- A modular upgrade path for processing, logic, and RF — independently and non-disruptively.
- An open-systems foundation that supports third-party application integration.
- A framework that can be matured incrementally toward operational fielding, not cliff-released.