> SLS-PROPRIETARY // NO EXTERNAL RELEASE

# Spindrift — SLS-409 (Program KINGFISHER)

**Public name:** Spindrift  **Tracking #:** SLS-409  **Codename:** KINGFISHER
**Category:** Sensors & Payloads  **Fiscal Year:** FY2026
**Contract award:** 13 February 2026

## Summary

Spindrift is the surface radar + ESM payload — the active and electronic-warfare
counterpart to OSPREY's passive optics. KINGFISHER detects and classifies surface
contacts by their radar returns and their own emissions, building an emitter
picture at standoff range. (Codename knowingly retained despite the historical
OS2U Kingfisher floatplane.)

## Notional Capabilities

- Compact AESA surface-search radar with ISAR imaging for classification
- Radar ESM (RESM): intercept, deinterleave, and classify emitters at standoff
- Pre-mission emitter library matching (friend/hostile/neutral/unknown)
- Fuses with AIS and EO/IR for high-confidence contact identification
- Feeds classified tracks and emitter alerts straight into ALDER (SLS-305)

## Program References

- Liu, Z. & Yu, P.S., "Classification, Denoising, and Deinterleaving of Pulse
  Streams With Recurrent Neural Networks," *IEEE Transactions on Aerospace and
  Electronic Systems*, 55(4):1624–1639, 2019.
  [doi:10.1109/TAES.2018.2874139](https://doi.org/10.1109/TAES.2018.2874139)
- Salish Littoral Systems, *KINGFISHER: Integrated Radar and ESM Payload for
  Unmanned Surface Surveillance*, SLS Technical Report TR-409, 2026.
- Mardia, H.K., "New techniques for the deinterleaving of repetitive
  sequences," *IEE Proceedings F – Radar and Signal Processing*,
  136(4):149–154, 1989.
  [doi:10.1049/ip-f-2.1989.0025](https://doi.org/10.1049/ip-f-2.1989.0025)
- SLS Electronic Warfare Group, *Emitter Deinterleaving and Library
  Classification for Maritime RESM*, SLS White Paper WP-SPINDRIFT-02, 2026.

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