Subsea Fiber DAS Dark-Ship Detection, Coastal Coverage & Radar Replacement Tool

Subsea Fiber DAS, Dark-Ship Cueing, Cable Protection, Warning Time, Localization, Sensor Density, Alert Workload & Radar Comparison

Subsea Fiber DAS Dark-Ship Detection, Coastal Coverage & Radar Replacement Tool

Test whether an existing subsea fiber can provide useful vessel-detection coverage for a cable, chokepoint or coastal corridor. Simple mode compares verified pilot performance with mission requirements. Advanced adds cable-segment variability, calibrated SNR range, AIS association, data throughput, analyst workload and a mission-based radar comparison without pretending DAS and radar are equivalent sensors.

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Need much more depth? Click Advanced above.Add cable segments, calibrated SNR range, AIS association, DAS data sizing, alert workload and radar-versus-DAS economics.

Mission Requirement

Define the corridor outcome first. The tool then tests the site-validated DAS performance against those mission requirements.

Required monitored corridor lengthkm of cable, route or chokepoint requiring coverage.

Minimum acceptable detection probability% for the vessel class and operating conditions being screened.

Maximum acceptable localization errorm. Use the mission requirement, not a generic DAS claim.

Minimum warning time before cable crossingminutes of geometric warning before a perpendicular crossing.

Existing Fiber & Pilot Performance

Total subsea fiber route availablekm physically available for the sensing concept.

Usable / optically reachable share% after optical reach, access, unusable sections and route constraints.

Validated reliable detection half-widthkm from fiber, based on a site pilot or defensible vessel-class test.

Validated vessel detection probability% at the selected operating point.

Validated localization errorm using one consistent measured error statistic.

Representative vessel speedknots for the warning-time screen.

Advanced Cable Segment Register

Use segment-level measured performance where the cable is not uniform. Advanced calculations use these rows when present.

Length km	Reliable range km	Pd %	Loc error m	Uptime %	Traffic weight	Sensitivity %

Detection Range: Measured or Calibrated SNR

Range basisSNR mode is a local calibration model, not a universal sonar equation.

Reference calibration distancekm.

Measured SNR at reference distancedB for the selected DAS feature and processing chain.

Effective spreading exponentSNR loss uses 10n log10(r/r0). Calibrate locally.

Frequency-band attenuationdB/km effective acoustic, seabed and processing loss term.

Net coupling / noise adjustmentdB. Negative means poorer coupling or higher noise.

Detection threshold SNRdB at the actual detector / ML operating point.

Warning Time & AIS Association

Track crossing angle to fiberdegrees. 90° is perpendicular; lower values are more parallel.

Detection dwell / hysteresisseconds before event confirmation.

Preprocessing + inference + C2 latencyseconds after the detection dwell.

Cable route survey / map uncertaintym.

AIS / GNSS position uncertaintym for association gating.

AIS age / correlation latencyseconds since the last position used for matching.

Association gate multiplier× combined engineering uncertainty.

Sensor Density, DAS Data & Compute

DAS channel spacingm.

Gauge lengthm. Influences spatial averaging and frequency response.

Acquisition sample ratesamples/second/channel.

Stored bytes per sample

Retention perioddays.

Storage / feature compression ratio8 means retained data is one-eighth of raw volume.

Interrogator optical reachkm per interrogator for the selected hardware and loss budget.

Detection Operations & Dark-Ship Workload

Relevant vessel transits / crossingsper day through the monitored mission corridor.

AIS-silent / unmatched vessel share% from local history or intelligence, not a generic global assumption.

False DAS alerts after filteringoperational alerts/day after the deployed filtering chain.

Analyst review time per unmatched alertminutes.

Coastal Radar Comparison & Economics

This is a mission-corridor cost comparison. Radar provides wide-area surface tracking; DAS is a passive linear sensing aperture tied to cable geometry.

Radar useful rangenautical miles for the target class and environment.

Radar usable sea sectordegrees used only for nominal sea-area comparison.

Effective corridor spacing per radar sitekm from the actual coastal design after overlap, terrain and siting constraints.

Radar detection probability

Radar uptime%.

Radar localization / track errorm representative mission value.

Radar false alerts after filteringalerts/day.

Display currencyDisplay only. No FX conversion is performed.

CAPEX per coastal radar site

Annual OPEX per radar site

DAS interrogator CAPEX each

DAS connection / installation / integration

AI / C2 / compute initial CAPEX

Annual fiber access / lease

Annual DAS software / compute / maintenance

Economic horizonyears.

Discount rate%.

Pilot / Integration Readiness

Optical path verifiedFiber access, amplification architecture, loss budget and interrogator connection are confirmed. Site-specific vessel pilot completedRange, Pd, localization and false-alert performance were measured across representative conditions. Cable route / coupling characterizedWeak and insensitive cable sections are mapped rather than assumed uniform. AIS / radar / EO / C2 fusion availableDAS detections can be correlated with cooperative and independent surveillance sources. Real-time compute path validatedPreprocessing, inference, alerting and data transport remain within the warning-time budget. Operational response concept approvedFalse alerts, unmatched candidates, evidence retention and escalation are assigned to an operating team.

Surveillance investment screening only: DAS performance is strongly site-dependent. Cable construction, burial, seabed coupling, optical loss, interrogator settings, gauge length, vessel signature, sea state, background noise, range and track geometry all matter. This tool is not a sonar equation, radar performance guarantee, operational replacement approval, classified threat model, fiber-optic link budget, lawful-intercept authorization or C2 certification.

2026 research basis: Full-scale research now demonstrates vessel detection and localization on operational or existing subsea fiber, including a 120 km UK-Ireland link and a 28 km North Sea cable. Published results also show that performance varies materially by cable sensitivity, distance, noise, vessel signature and processing method. Use published results as pilot benchmarks only and replace them with local measurements before procurement or any radar-substitution decision. IMO AIS carriage requirements remain a cooperative identification layer; DAS can provide non-cooperative acoustic cues but does not itself provide vessel identity. Sea-Scan 2026 · Marlinks-NS DAS 2026 · Trondheimsfjord DAS vessel study · IMO AIS

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Subsea Fiber DAS Dark-Ship Detection, Coastal Coverage & Radar Replacement Tool