ISO 25451:2026

Ships and marine technology — Technical requirements and guidelines for seafloor mapping with uncrewed marine vehicles

This document specifies the technical requirements and guidelines for seafloor mapping with uncrewed marine vehicles, including uncrewed surface vehicles (USVs) and uncrewed underwater vehicles (UUVs). This document covers navigation and positioning, uncrewed vehicle assembly, survey parameter setting, single-beam and multi-beam echo sounding, and data processing. This document is applicable to uncrewed marine vehicles in estuaries, offshore and open sea areas.

Navires et technologie maritime — Exigences techniques et lignes directrices pour la cartographie des fonds marins réalisée par des engins sans équipage

General Information

• Status: Published
• Publication Date: 10-May-2026
• ICS: 07.060 - Geology. Meteorology. Hydrology
• ICS: 47.080 - Small craft
• Technical Committee: ISO/TC 8/SC 13 - Marine technology
• Current Stage: 6060 - International Standard published
• Start Date: 11-May-2026
• Due Date: 23-Dec-2027
• Completion Date: 11-May-2026

Overview

ISO 25451:2026 - Ships and Marine Technology: Technical Requirements and Guidelines for Seafloor Mapping with Uncrewed Marine Vehicles provides standardized procedures and technical guidelines for conducting seafloor mapping using uncrewed marine vehicles (UMVs), including both uncrewed surface vehicles (USVs) and uncrewed underwater vehicles (UUVs). This international standard supports safe, reliable, and accurate seafloor data collection in estuaries, offshore zones, and open sea environments. Key aspects covered include navigation and positioning, vehicle and instrument setup, survey methods, bathymetric measurement, and survey data management.

Key Topics

• Navigation and Positioning: Recommends the use of global navigation satellite systems (GNSS), ultra-short baseline (USBL), and long baseline (LBL) acoustic positioning to ensure accurate vessel location. The document outlines accuracy requirements for both surface and underwater operations.
• Vehicle Assembly and Inspection: Sets standards for pre-launch inspection and readiness of uncrewed vehicles, ensuring system integrity, watertightness, and instrument functionality.
• Survey Parameter Setting: Details configuration for survey instruments such as single-beam and multi-beam echo sounders, with attention to calibration, sonar alignment, and relevant system offsets.
• Survey Planning: Provides methodologies for mission line planning (parallel to isobaths or perpendicular to currents), crossline design, and full survey network coverage.
• Data Collection and Processing: Specifies requirements for data cleaning, outlier detection, correction protocols (sound velocity, tide height), and the structure of final datasets.
• Operational Guidelines: Addresses launch and recovery procedures, communication system installation, and compliance with safety and regulatory frameworks such as COLREGs.

Applications

ISO 25451:2026 is highly relevant to the following applications in the marine industry:

• Hydrographic Surveys: Facilitates the creation of bathymetric maps and supports the development of nautical charts for navigational safety.
• Offshore Engineering: Supports seabed mapping required for oil and gas exploration, wind farm site assessment, and subsea cable or pipeline installation.
• Marine Research: Provides a robust framework for oceanographic studies, habitat mapping, and environmental monitoring.
• Resource Exploration: Assists in locating seabed mineral resources and evaluating subsea geological structures.
• Regulatory and Compliance: Ensures uniform survey practices and reporting standards across international marine projects.

By providing a standard approach to uncrewed marine vehicle operation and seafloor mapping, the document enhances data consistency, survey efficiency, and marine operational safety.

Related Standards

For comprehensive marine surveys and technology projects, ISO 25451:2026 references and complements several other key standards and best practices:

• ISO/TS 23860: Autonomous ship systems – Vocabulary.
• ISO 5411:2024: Terminology and requirements for submersible vehicles.
• ISO 19111:2019: Geographic information – Referencing by coordinates.
• IHO S-44 (Edition 6.2.0): International standards for hydrographic surveys.
• IMCA S-003 & S-017: Guidelines for using multibeam echo sounders and USBL systems in offshore surveys.
• IMCA S-027: Use of GNSS for tide calculations.
• IMO COLREGs: Navigation regulations for preventing ship collisions.
• UKHO Hydrographic Survey Specification: Additional best practices for seabed mapping projects.

By adhering to ISO 25451:2026 alongside these standards, organizations can ensure that seafloor mapping with uncrewed marine vehicles is conducted to the highest standards of precision, safety, and efficiency.

Standards Content (Sample)

International
Standard
ISO 25451
First edition
Ships and marine technology —
2026-05
Technical requirements and
guidelines for seafloor mapping
with uncrewed marine vehicles
Navires et technologie maritime — Exigences techniques et lignes
directrices pour la cartographie des fonds marins réalisée par des
engins sans équipage
Reference number
© ISO 2026
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Technical provisions . 2
4.1 General .2
4.2 Standard of time and space .2
4.2.1 Geographic coordinate system .2
4.2.2 Vertical reference .2
4.2.3 Standard of time .2
4.2.4 Projection.3
4.3 Measurement accuracy .3
4.3.1 Navigation and positioning .3
4.3.2 Water depth measurements .3
4.3.3 Sound velocity profile (SVP) measurement .3
4.3.4 Height of tide measurement .4
4.4 Seafloor survey operation planning .4
4.4.1 Survey method .4
4.4.2 Survey mission line planning .4
4.5 Mobilization ship (MOSHIP) selection for survey operations by USV/UUV .5
4.5.1 MOSHIP selection for USV .5
4.5.2 MOSHIP selection for UUV .5
4.6 Survey preparation .5
4.6.1 USV/UUV pre-launch inspection .5
4.6.2 Instrument inspections .6
4.7 Survey implementation .6
4.7.1 Communication system installation .6
4.7.2 Pre-launch testing .7
4.7.3 Launch and recovery .8
4.7.4 Seafloor survey .8
4.7.5 Survey process .9
4.8 Seafloor survey data.9
4.9 Data processing and output .10
4.9.1 Data cleaning .10
4.9.2 Data correction .10
4.9.3 Data output .10
Bibliography .11

iii
Foreword
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in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
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This document was prepared by Technical Committee ISO/TC 8, Ships and marine technology, Subcommittee
SC 13, Marine technology.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
Introduction
Seafloor mapping is a fundamental marine survey activity, which can produce results including bathymetric
maps, seafloor topographic maps and geomorphologic maps. Traditional methods of seafloor mapping
include single-beam echo sounding and multi-beam echo sounding. Recently, uncrewed surface vehicles
(USVs) and uncrewed underwater vehicles (UUVs) have been increasingly employed in seafloor mapping,
enriching the technical methods and diversifying the survey platforms. These surveys now cover areas such
as estuaries, coastal regions, and the open sea.
Currently, the technology for seafloor mapping using uncrewed marine vehicles has matured and is widely
applied in marine oil and gas exploration, seabed mineral resource exploration, offshore engineering design
and construction, as well as undersea tunnel and pipeline installation. Recognition of this technology
by relevant industries continues to grow. This document concerns the functions and characteristics of
uncrewed marine vehicles and the survey instruments they carry, specifically addressing the technical
features, application environments, and functional requirements for seafloor mapping with uncrewed
marine vehicles.
This document has been developed to standardize the technical design, field survey procedures, data
processing and data output for seafloor mapping using USVs or UUVs equipped with single-beam or multi-
beam echo sounders. This document aims to enhance the quality of field surveys and the accuracy of seafloor
mapping data.
v
International Standard ISO 25451:2026(en)
Ships and marine technology — Technical requirements
and guidelines for seafloor mapping with uncrewed marine
vehicles
1 Scope
This document specifies the technical requirements and guidelines for seafloor mapping with uncrewed
marine vehicles, including uncrewed surface vehicles (USVs) and uncrewed underwater vehicles (UUVs).
This document covers navigation and positioning, uncrewed vehicle assembly, survey parameter setting,
single-beam and multi-beam echo sounding, and data processing.
This document is applicable to uncrewed marine vehicles in estuaries, offshore and open sea areas.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
uncrewed marine vehicle
fully automated vehicle capable of navigating on the surface or underwater according to a predefined
mission by means of satellite or underwater positioning and its own sensors
3.2
seafloor mapping
measurement and analysis of seafloor relief patterns and features
3.3
mean sea level
MSL
average level of the surface of the sea over all stages of tide and seasonal variations
Note 1 to entry: Mean sea level in a local context normally means mean sea level for the region calculated from
observations at one or more points over a given period of time.
[SOURCE: ISO 19111:2019, 3.1.41, modified — the domain "" has been deleted; last two sentences
of note 1 to entry have been deleted.]
3.4
global navigation satellite system
GNSS
satellite based navigation system that provides autonomous global positioning of a receiving device
[SOURCE: ISO ISO 19901-10:2021, 3.41, modified — note 1 to entry has been deleted.]

3.5
ultra-short baseline acoustic positioning system
USBL acoustic positioning system
underwater sound positioning system in which an array of acoustic transducers is deployed on a support
ship and transducers are all built into a single transceiver assembly
[SOURCE: ISO 5411:2024, 3.6.10]
3.6
long baseline acoustic positioning system
LBL acoustic positioning system
underwater sound positioning system which consists of a number of acoustic transponder beacons moored
in fixed locations on the seabed or mounted on fixed locations of objects such as a support ship
[SOURCE: ISO 5411:2024, 3.6.11]
3.7
real time kinematic positioning
RTK
application of surveying to correct for common errors in current global navigation satellite system (3.4)
3.8
one pulse per second
1PPS
precise time marker that emits a pulse every second
Note 1 to entry: 1PPS signals are output by some global navigation satellite system (3.4) receivers and used for precise
timekeeping and time measurement
3.9
outlier
data point in multibeam bathymetry that significantly deviates from the true seafloor depth or from
surrounding soundings
Note 1 to entry: Such points typically arise from noise, unfavourable beam geometry, water-column disturbances,
mismatched sound-speed profiles, or motion-sensor errors.
4 Technical provisions
4.1 General
Seafloor mapping with an uncrewed marine vehicle includes field survey design, USV and UUV preparation,
parameter setting, bathymetric survey and data processing.
4.2 Standard of time and space
4.2.1 Geographic coordinate system
[5]
The World Geodetic System 1984 (WGS84) coordinate system should be adopted.
4.2.2 Vertical reference
The mean sea level should be adopted.
4.2.3 Standard of time
Coordinated Universal Time (UTC) should be adopted.

4.2.4 Projection
Grid positions should be referenced to the Universal Transverse Mercator (UTM) grid for areas between
latitudes 80° South and 84° North.
For regions beyond the above range, within the polar areas, the Universal Polar Stereographic (UPS)
projection should be used.
4.3 Measurement accuracy
4.3.1 Navigation and positioning
4.3.1.1 Surface navigation and positioning
GNSS and a ship’s compass are recommended for surface navigation and positioning. The following
recommendations apply.
a) An independent satellite positioning system should be available.
b) The effective range of positioning and correction signals should cover the entire survey area.
c) The positioning error of the satellite differential system should not exceed 1,0 m.
4.3.1.2 Underwater navigation and positioning
GNSS, ultra-short baseline (USBL) or long baseline (LBL) acoustic positioning systems are recommended for
use in underwater navigation and positioning. The following recommendations apply.
a) Horizontal positioning error should not exceed 5,0 m, or 1,0 m when using real-time satellite
differentiation.
b) Positioning accuracy of USBL acoustic positioning systems should be smaller than 0,5 % of slant
[8]
distance.
c) Positioning accuracy of LBL acoustic positioning systems should be smaller than 10,0 m.
NOTE The slant distance refers to the distance between the USBL acoustic positioning system and the UUV.
4.3.2 Water depth measurements
The selection of applicable standards for water depth measurement should be determined by the intended
application and operational requirement.
For hydrographic surveys supporting nautical charting, navigation safety, or other official hydrographic
[6]
purposes, IHO S-44, Edition 6.2.0, Standards for Hydrographic Surveys is recommended.
For offshore engineering, subsea construction, inspection, or other industrial survey activities, IMCA S-003,
[7]
Guidelines for The Use of Multibeam Echosounders for Offshore Surveys is recommended.
4.3.3 Sound velocity profile (SVP) measurement
For SVP measurement, the following recommendations apply.
a) Measurement accuracy should be smaller than 0,5 m/s.
b) Working depth of the SVP system should exceed the maximum water depth of the survey area.
c) SVP measurement should comply with project planning requirements specified by project sponsor.
d) SVP measurement should be evenly distributed throughout the survey area, and the time and location
of the measurement should be recorded.

e) The number of SVPs should be increased under special hydrographic conditions, such as shallow water
or estuarin
...