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# Helmsman — SLS-301 (Program CEDAR)

**Public name:** Helmsman  **Tracking #:** SLS-301  **Codename:** CEDAR
**Category:** Autonomy & C2  **Fiscal Year:** FY2023
**Contract award:** 30 May 2023

## Summary

Helmsman is the core autonomy and navigation stack that runs on every SLS
vehicle. CEDAR is the "trees = software" foundation of the catalog: a portable
guidance/navigation/control layer providing COLREGS-compliant maneuvering,
GNSS-denied dead-reckoning, and a planner that hands off cleanly to the TIDEFALL
(SLS-305) fleet C2 suite. Awarded alongside HERON in FY2023 so the flagship USV
had a flight-ready brain at delivery.

## Notional Capabilities

- Hybrid collision-avoidance: rule-based COLREGS layer + velocity-obstacle
  geometry, with a reinforcement-learning policy for dense traffic
- Global/local planners (A*, D*, sampling-based) over prior and live bathymetry
- GNSS-denied navigation via inertial + terrain/acoustic correlation
- Deterministic, model-checkable decision core for certification
- Common API shared across USV (HERON, ORCA) and UUV (SALMON, ROCKFISH) hulls

## Program References

- Kuwata, Y., Wolf, M.T., Zarzhitsky, D., & Huntsberger, T.L., "Safe Maritime
  Autonomous Navigation With COLREGS, Using Velocity Obstacles," *IEEE Journal
  of Oceanic Engineering*, 39(1):110–119, 2014.
  [IEEE 6519944](https://ieeexplore.ieee.org/document/6519944/)
- Salish Littoral Systems, *CEDAR: A COLREGS-Compliant Guidance and Navigation
  Stack for Mixed USV/UUV Fleets*, SLS Technical Report TR-301, 2023.
- "Formal Verification of Path Planning Safety and Reachability in Unmanned
  Surface Vehicles," *Springer LNCS*, 2024.
  [doi:10.1007/978-981-97-5675-9_2](https://link.springer.com/chapter/10.1007/978-981-97-5675-9_2)
- SLS Autonomy Group, *Velocity-Obstacle Collision Avoidance Under Rule
  Constraints*, SLS White Paper WP-CEDAR-01, 2023.

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