Page 17: of Marine Technology Magazine (Jul/Aug 2026)

A SEA-KIT X class USV

RADAR PROCESSING built for Fugro. SEA-KIT was an early adopter of Cambridge Pixel’s radar processing.

FROM RADAR FROM RADAR

RETURNS RETURNS

TO SAFE TO SAFE

DECISIONS: DECISIONS:

Radar Processing Radar Processing for Maritime for Maritime

AutonomyAutonomy

Credit: SEA-KIT

By Rob Helliar, Cambridge Pixel ithout a human onboard with all-around situ- sor settings. Radar should complement other sensors rather than ational awareness, the sensor systems of au- replace them, but it remains an important independent source of tonomous and remotely operated vessels are information that autonomous systems should not ignore.

Wcritical for navigational safety and mission effectiveness. Much attention goes to the onboard camera From echoes to detections suite, but radars, and their associated processing, are also a A radar will output video, in either analogue or, increasingly, part of the sensor system mix. digital form. In radar terminology, “video” means the stream

When developers specify radar for an autonomous vessel, atten- of return intensities from the radar, as opposed to image-like tion often goes to factors such as range, resolution, antenna size, camera footage. It is a constantly changing ? eld of re? ections, and technology. Those choices matter, but they do not determine in polar space.

what the autonomy system or remote operator ultimately re- The radar video picture may be cluttered and complex. A ceives. This is determined by the quality of the radar processing. steel ship may produce a strong radar return, but so may a har-

An autonomy control system needs machine-readable infor- bor wall or a bridge. A small in? atable boat may produce only mation; a remote operator needs the maritime picture present- a weak radar echo, which may be obscured by waves creating ed as clearly as possible to aid decision-making and reduce sea clutter. Rain creates unwanted returns, and land and port cognitive load. In both cases, a suite of sensors, with data pro- structures produce persistent re? ections. Effective processing cessed and fused into usable information, is ideal. is therefore essential.

Radar processing software ? rst acquires radar video data

Why radar remains important through a hardware interface or a digital network stream. It

An autonomous vessel may carry cameras, an Automatic then applies ? ltering and detection techniques to ? nd returns

Identi? cation System (AIS) receiver, Global Navigation Satel- that stand out from the background.

lite System (GNSS) receivers, LiDAR, sonar, and other sen- This is more involved than simply setting a single threshold sors. Cameras can help identify an object, while AIS can pro- above which a radar video return is considered to be a con- vide a transmitting vessel’s declared identity, position, course, tact. The background changes with range, platform motion, and speed. However, neither alone provides a complete picture. weather, and sea state. Settings suitable for calm water may

Cameras can be affected by darkness, glare, fog, rain, and produce many false detections in heavy rain; settings that sup- spray. Most can only provide contact bearing, or, at best, a press them may hide a genuine target.

rough estimate of range. Small and ? xed contacts are unlikely Adaptive processing responds to local conditions. Dynamic to carry AIS transponders, and those that are ? tted with AIS can thresholding adjusts to changing noise levels, while geograph- have it switched off or incorrectly con? gured. However, radar ic masks reduce processing over known land or structures. can operate at long range in poor visibility and provide accurate Where software allows, different radar processing settings can position information for small and non-co-operative contacts. be applied in different regions, allowing greater sensitivity in

Radar is not infallible. Performance is affected by the installa- a channel or directly ahead of the vessel. The goal is useful tion, sea state, weather, target size and re? ectivity, and proces- detections without excessive false alarms.

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