Autonomous Shipping Ocean Positioning

Regulatory and Operational Context

The IMO Maritime Safety Committee adopted at MSC 105 a roadmap toward a non-mandatory MASS Code by 2025 and a mandatory goal-based MASS Code expected to enter into force on 1 January 2028. The Code is being developed against the existing instruments, principally the International Convention for the Safety of Life at Sea (SOLAS), the International Regulations for Preventing Collisions at Sea (COLREGs), the STCW Convention on training and watchkeeping, and MARPOL on environmental reporting. The four IMO degrees of autonomy, from decision-support with a crew aboard to fully autonomous operation, define the regulatory aperture within which the Code's positioning, reporting, and remote-control provisions will be specified.

Positioning and navigation operate under a parallel set of instruments. SOLAS Chapter V regulates carriage of navigation equipment, including the Automatic Identification System under Regulation 19, with Class A AIS required for SOLAS vessels and Class B for many non-SOLAS commercial and pleasure craft. The IMO e-Navigation strategy, developed jointly with IALA and IHO, defines the architecture under which shipboard, shoreside, and communication-link information services are harmonized. Recommended performance standards for shipborne positioning, navigation and timing data processing, articulated in MSC.1/Circ.1575 and successor instruments, formalize the requirement for resilient PNT inputs. The IALA G1117 guideline on the use of resilient PNT in maritime operations describes the integration of GNSS, terrestrial radio-navigation systems such as eLoran, inertial sensing, and visual aids into a coherent navigation solution.

The Architectural Requirement

A MASS vessel must be able to assert its own position with sufficient confidence that a remote operator, a port-state authority, a flag-state authority, and a counterparty vessel can all rely on the assertion at the moment they receive it. The required confidence is not merely a numerical accuracy figure but a lineage: where the position came from, which sensors contributed, which contributions were corroborated, and under what conditions the derivation was made. This lineage must persist across handoff between flag-state and port-state jurisdictions, across transitions from open ocean to coastal water and into pilotage, and across degradation events that knock GNSS out of the available sensor set.

The architectural requirement is therefore a position substrate whose authority does not collapse to a single global navigation satellite system. The substrate must support derivation from the heterogeneous set of inputs that the IALA resilient-PNT guideline contemplates, must provide on-demand densification when surrounding traffic or shoreside aids are sparse, and must continue to operate, with degraded but characterized confidence, when GNSS is unavailable or untrustworthy. None of these properties is provided by a conventional GNSS receiver, and none is provided by any single supplementary aid in isolation.

Why GNSS-Centric Positioning Falls Short

GNSS spoofing in maritime operations is no longer hypothetical. The U.S. Maritime Administration has issued recurring advisories on GPS interference and spoofing in the eastern Mediterranean, the Black Sea, the Persian Gulf, and the Strait of Hormuz; operators have reported anomalous position fixes inland of the actual track, circular drift patterns at the geographic locations of major ports, and periods of complete loss of fix. Jamming events, both deliberate and incidental, are routine in some operating regions. The threat environment is now a permanent feature of certain trade routes rather than an exceptional condition. A positioning architecture that treats GNSS as the primary input and supplementary aids as backup misallocates the burden of confidence.

Procedural compliance compounds the problem. AIS transmissions under SOLAS Regulation 19 carry the position the vessel asserts; if the asserted position is the spoofed GNSS fix, the vessel reports a spoofed position to every other vessel and shoreside authority within range. AIS spoofing, in which the AIS transmission itself is forged, is a separate but related threat documented by the U.S. Coast Guard and MARAD. e-Navigation services that consume AIS as authoritative position propagate the error. Audit reconstruction after a near-miss or a grounding depends on logs that, in the GNSS-centric architecture, capture only the asserted fix and not the lineage that produced it. The reconstruction therefore cannot distinguish between sensor failure, environmental interference, and adversarial action, which is precisely the distinction that flag-state and port-state authorities must draw.

What the Mesh-Coordinates Primitive Provides

The mesh-coordinates primitive derives position from a consensus among peers rather than from a single satellite system. Vessels in proximity exchange ranging observations using the radio, optical, radar, and acoustic modalities they already carry; shoreside aids to navigation, including IALA AIS base stations and DGNSS reference stations, contribute as peers when in range; the vessel's own inertial and odometric sensors contribute as internal peers under the same consensus rule. Each contribution carries an authority credential that identifies the source and the conditions under which the observation was made. The vessel's derived position is the consensus output, with the credential chain preserved as lineage.

On-demand densification is a first-class capability. When a MASS vessel approaches a region of sparse traffic or limited shoreside coverage, the substrate can request additional ranging observations from any peer in range, prioritizing modalities and peers whose credentials are most authoritative for the operating context. When the vessel enters a port approach and pilotage, density increases naturally and the consensus tightens. When GNSS is degraded, GNSS-derived contributions are weighted down or excluded under a characterized rule, and the vessel continues to operate with the remaining contributions; the resulting position carries reduced confidence, but the reduction is itself attested in the lineage rather than concealed.

Compliance Mapping

SOLAS Chapter V positioning and navigation requirements are met by the consensus output, with the credential chain providing the lineage that the resilient-PNT performance standards require. AIS transmissions under Regulation 19 carry the consensus position rather than a raw GNSS fix, eliminating the propagation of spoofed positions into the shared traffic picture; AIS-spoofing detection is supported because incoming AIS positions can be cross-checked against the local consensus. COLREGs Rule 5 lookout and Rule 7 risk-of-collision determinations operate on the consensus position, with confidence intervals that reflect the actual sensor environment rather than the nominal GNSS specification. STCW remote-operator certification under emerging MASS Code provisions is supported because the operator receives a position with characterized lineage rather than a single number whose provenance is opaque.

The IALA G1117 resilient-PNT integration model maps directly onto the substrate, with each contemplated input class represented as a peer authority. The IMO e-Navigation Maritime Service Portfolios consume the consensus output through the same channels they consume conventional PNT. Flag-state and port-state authorities receive position records whose lineage supports audit reconstruction; this in turn supports investigation under the IMO Casualty Investigation Code without the lineage gap that GNSS-centric architectures impose. Cross-jurisdictional handoff between flag and port states is supported because the authority federation can be extended without altering the underlying derivation rule.

Adoption Pathway

Adoption can begin on a single MASS deployment or a single trade route with cooperating conventionally-crewed vessels and shoreside aids. Existing demonstrations including Yara Birkeland on its Norwegian short-sea route, the Mayflower Autonomous Ship trans-Atlantic deployments, and emerging autonomous-tanker programs in coastal trade have already aggregated the sensor diversity the substrate requires; the addition is the consensus and lineage layer over those sensors. Initial benefit is operational resilience in known GNSS-interference regions, where the consensus continues to deliver a usable position when GNSS is degraded.

As MASS Code provisions enter into force from 2028, the substrate provides a ready answer to the resilience and lineage requirements that the Code's goal-based standards will impose. Class society approval, flag-state acceptance, and port-state recognition are advanced incrementally as the credential federation grows to include classification societies, flag-state administrations, and IALA-recognized shoreside aids. Conventionally-crewed vessels participate as peers without adopting the autonomous control stack, broadening the consensus base and reinforcing the safety case for the autonomous operators. The trajectory is route-by-route, sensor-by-sensor, and respectful of the existing maritime regulatory architecture rather than in competition with it.

The mesh-coordinates primitive is disclosed in USPTO provisional 64/049,409 as a structural condition over peer-derived position rather than as a navigation product. The architectural property — that position is a consensus output with a credential chain rather than a single sensor's assertion — is technology-neutral over ranging modality (radio, optical, radar, acoustic), over consensus algorithm, and over credential scheme, and it composes hierarchically across vessel-internal, local-traffic, regional-shoreside, and flag-state authority levels. Existing shipboard integrated navigation systems from Furuno, Wartsila, Kongsberg, Raytheon Anschutz, and similar suppliers continue to provide their sensor processing and ECDIS portrayal; the mesh-coordinates layer composes above them as the consensus and lineage substrate. Commercial fit is per-credentialed-vessel and per-route-federation rather than per-receiver, aligning with how flag-state administrations, classification societies, and major shipping lines actually procure positioning resilience. The substrate's audit lineage is portable across vendor changes for the operational life of the vessel and survives flag transfer, ownership transfer, and class re-certification.