ISO/FDIS 25451
(Main)Ships and marine technology — Technical requirements and guidelines for seafloor mapping with uncrewed marine vehicles
Ships and marine technology — Technical requirements and guidelines for seafloor mapping with uncrewed marine vehicles
This document specifies the technical requirements for navigation and positioning, unmanned vehicle assembly, survey parameter setting, single-beam and multi-beam echo sounding, and data processing of seafloor mapping with marine unmanned vehicle, including unmanned surface vehicle (USV) and unmanned underwater vehicle (UUV). This document is applicable to survey implementation, data processing of seafloor mapping with marine unmanned vehicles in estuaries, offshore and open sea areas.
Titre manque
General Information
- Status
- Not Published
- Technical Committee
- ISO/TC 8/SC 13 - Marine technology
- Current Stage
- 5000 - FDIS registered for formal approval
- Start Date
- 05-Dec-2025
- Completion Date
- 14-Jan-2026
Overview
ISO/FDIS 25451:2026 – Ships and Marine Technology – Technical Requirements and Guidelines for Seafloor Mapping with Uncrewed Marine Vehicles establishes internationally-recognized technical requirements and best practices for using uncrewed marine vehicles (UMVs) in seafloor mapping. This ISO standard addresses navigation and positioning, vehicle assembly, survey planning, instrument calibration, data collection through single-beam and multi-beam echo sounding, as well as comprehensive data processing protocols. The guidance covers both uncrewed surface vehicles (USVs) and uncrewed underwater vehicles (UUVs) in a variety of marine environments, including estuaries, offshore regions, and open sea areas.
Adoption of this standard helps enhance the quality and reliability of seafloor surveying operations, providing a unified framework for hydrographic and oceanographic practitioners, offshore industries, and marine researchers.
Key Topics
Navigation and Positioning
The standard defines usage and requirements for satellite positioning systems (GNSS), ultra-short baseline (USBL), and long baseline (LBL) acoustic positioning technologies. Criteria are provided for both surface and underwater navigation with an emphasis on positional accuracy appropriate to the survey objectives.Assembly and Pre-launch Preparation
Guidance is included for ensuring USVs and UUVs and their payloads are properly assembled, inspected, and tested before deployment. This includes checks on power, control systems, integrity of cabling, and watertight compartments.Survey Parameter Setting
Detailed recommendations are given for setting survey parameters such as coordinate systems (WGS84), vertical references (mean sea level), time standards (UTC), and projection systems (UTM or UPS, as appropriate for geographic location).Echo Sounding
The document outlines operational principles for both single-beam and multi-beam echo sounders, including instrument calibration and recommended measurement practices. References to IHO S-44 and IMCA S-003 are advised for water depth measurements, depending on the survey’s end-use.Data Processing and Quality Assurance
Requires systematic procedures for data cleaning, correction, and output. Provisions for handling sound velocity profiles, height of tide measurements, and error-checking are highlighted to ensure data integrity.
Applications
ISO/FDIS 25451 is highly relevant for:
Marine Resource Exploration
Facilitates accurate mapping for offshore oil & gas, seabed mineral prospecting, and marine biology studies.Offshore Engineering and Construction
Supports undersea tunnel development, offshore wind farm planning, pipeline and cable route surveys, and construction monitoring.Hydrographic Surveying
Enables national hydrographic offices, navies, and private survey companies to produce high-quality bathymetric, topographic, and geomorphological maps using uncrewed platforms.Environmental Monitoring
Promotes consistent practices for ecological studies, sediment transport analysis, and marine habitat mapping in sensitive or hard-to-access regions.Research and Development
Provides research teams with a standardized approach for deploying and exploiting uncrewed marine vehicles in oceanographic investigations.
Related Standards
Organizations implementing ISO/FDIS 25451 may also find the following standards beneficial:
IHO S-44 – Standards for Hydrographic Surveys:
Benchmark for hydrographic survey accuracy and quality assurance.IMCA S-003 – Guidelines for the Use of Multibeam Echosounders for Offshore Surveys:
Practical advice on multi-beam echosounder operation in industrial and engineering contexts.ISO 19111 – Geographic Information/Geomatics – Spatial referencing by coordinates:
Framework for managing coordinate systems and spatial data integrity.ISO 19901-10 – Petroleum and natural gas industries – Offshore structures:
Technical requirements for offshore engineering, useful where seafloor mapping intersects with oil & gas infrastructure.
By adhering to ISO/FDIS 25451, organizations improve operational efficiency, ensure data comparability, and enhance safety and environmental stewardship during marine survey operations with uncrewed vehicles.
ISO/FDIS 25451 - Ships and marine technology — Technical requirements and guidelines for seafloor mapping with uncrewed marine vehicles Released:27. 01. 2026
REDLINE ISO/FDIS 25451 - Ships and marine technology — Technical requirements and guidelines for seafloor mapping with uncrewed marine vehicles Released:27. 01. 2026
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Frequently Asked Questions
ISO/FDIS 25451 is a draft published by the International Organization for Standardization (ISO). Its full title is "Ships and marine technology — Technical requirements and guidelines for seafloor mapping with uncrewed marine vehicles". This standard covers: This document specifies the technical requirements for navigation and positioning, unmanned vehicle assembly, survey parameter setting, single-beam and multi-beam echo sounding, and data processing of seafloor mapping with marine unmanned vehicle, including unmanned surface vehicle (USV) and unmanned underwater vehicle (UUV). This document is applicable to survey implementation, data processing of seafloor mapping with marine unmanned vehicles in estuaries, offshore and open sea areas.
This document specifies the technical requirements for navigation and positioning, unmanned vehicle assembly, survey parameter setting, single-beam and multi-beam echo sounding, and data processing of seafloor mapping with marine unmanned vehicle, including unmanned surface vehicle (USV) and unmanned underwater vehicle (UUV). This document is applicable to survey implementation, data processing of seafloor mapping with marine unmanned vehicles in estuaries, offshore and open sea areas.
ISO/FDIS 25451 is classified under the following ICS (International Classification for Standards) categories: 07.060 - Geology. Meteorology. Hydrology; 47.080 - Small craft. The ICS classification helps identify the subject area and facilitates finding related standards.
ISO/FDIS 25451 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
FINAL DRAFT
International
Standard
ISO/TC 8/SC 13
Ships and marine technology —
Secretariat: SAC
Technical requirements and
Voting begins on:
guidelines for seafloor mapping
2026-02-10
with uncrewed marine vehicles
Voting terminates on:
2026-04-07
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
FINAL DRAFT
International
Standard
ISO/TC 8/SC 13
Ships and marine technology —
Secretariat: SAC
Technical requirements and
Voting begins on:
guidelines for seafloor mapping
with uncrewed marine vehicles
Voting terminates on:
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2026
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
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Published in Switzerland Reference number
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative reference . 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 clean .10
4.9.2 Data correction .10
4.9.3 Data output .10
Bibliography .11
iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
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
FINAL DRAFT International Standard ISO/FDIS 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 (USV) and uncrewed underwater vehicles (UUV). 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 reference
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
[7]
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.
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Ships and marine technology – — Technical requirements and
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guidelines for seafloor mapping with uncrewed marine
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St l D fi iti
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All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
Adjust space between Asian text and numbers
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: + 41 22 749 01 11
EmailE-mail: copyright@iso.org
Formatted: German (Germany)
Website: www.iso.orgwww.iso.org
Formatted: German (Germany)
Published in Switzerland
Formatted: Font: 11 pt
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0 pt, Line spacing: single
ii © ISO #### 2026 – All rights reserved
ii
ISO/DISFDIS 25451:20252026(en) Formatted: Font: 11 pt, Font color: Auto
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Contents
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Foreword . v
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Introduction . vi
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1 Scope . 1 Adjust space between Asian text and numbers
2 Normative reference . 1
3 Terms and definitions . 1
4 Technical provisions . 3
4.1 General. 3
4.2 Standard of time and space . 3
4.3 Measurement accuracy . 3
4.4 Seafloor survey operation planning . 5
4.5 Mobilization ship (MOSHIP) selection for survey operations by USV/UUV . 5
4.6 Survey preparation . 6
4.7 Survey implementation . 7
4.8 Seafloor survey data . 11
4.9 Data processing and output . 11
Bibliography . 13
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative reference . 1
3 Terms and definitions . 1
4 Requirements . 2
4.1 General. 2
4.2 Standard of time and space . 3
4.2.1 Geographic coordinate system. 3
4.2.2 Vertical reference . 3
4.2.3 Standard of time . 3
4.2.4 Projection . 3
4.3 Accuracy requirements . 3
4.3.1 Navigation and positioning . 3
4.3.2 Water depth measurements . 3
4.3.3 Sound velocity profile (SVP) measurement . 4
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 Mobilisation ship (MOSHIP) selection for survey operations by USV/UUV . 5
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4.6 Survey preparation . 6
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4.7 Survey implementation . 6
4.7.1 Communication system installation . 6
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4.7.2 Pre-launch testing. 7
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4.7.3 Launch and recovery . 8
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4.7.5 Survey process . 10
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iii
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4.9 Data processing and output . 10
4.9.1 Data clean . 10
4.9.2 Data correction . 11
4.9.3 Data output. 11
Bibliography . 12
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iv © ISO #### 2026 – All rights reserved
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Foreword
Formatted: Font: Cambria, Font color: Auto
ISO (the International Organization for Standardization) is a worldwide federation of national standards Formatted: HeaderCentered, Left, Space After: 0 pt,
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through Line spacing: single
ISO technical committees. Each member body interested in a subject for which a technical committee has been
Formatted: Adjust space between Latin and Asian text,
established has the right to be represented on that committee. International organizations, governmental and
Adjust space between Asian text and numbers
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of
ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Formatted: English (United Kingdom)
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
Formatted: Font color: Auto
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents.www.iso.org/patents. ISO shall not be held responsible for identifying any or all such
patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.htmlwww.iso.org/iso/foreword.html.
Formatted: English (United Kingdom)
This document was prepared by Technical Committee ISO/TC 8, Ships and marine technology, Subcommittee
Formatted: Adjust space between Latin and Asian text,
SC 13, Marine technology.
Adjust space between Asian text and numbers
Any feedback or questions on this document should be directed to the user’s national standards body. A
Formatted: English (United Kingdom)
complete listing of these bodies can be found at www.iso.org/members.html.www.iso.org/members.html.
Formatted: English (United Kingdom)
Formatted: Font: 10 pt
Formatted: Font: 10 pt
Formatted: FooterCentered, Left, Space Before: 0 pt
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After: 0 pt
v
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Formatted: HeaderCentered
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Introduction
Adjust space between Asian text and numbers
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 washas 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.
In this document, the following verbal forms are used:
— “shall” indicates a requirement;
— “should” indicates a recommendation;
— “can” indicates a possibility or a capability;
— “may” indicates a permission.
Formatted: Font: 11 pt
Formatted: FooterPageRomanNumber, Space Before:
0 pt, Line spacing: single
vi © ISO #### 2026 – All rights reserved
vi
DRAFT International Standard ISO/DIS 25451:2025(en)
Ships and marine technology – — Technical requirements and
guidelines for seafloor mapping with uncrewed marine
vehiclevehicles
1 Scope
[1]
This document specifies the technical requirements and guidelines for seafloor mapping with uncrewed
marine vehicles, including uncrewed surface vehiclevehicles (USV) and uncrewed underwater vehiclevehicles
(UUV). 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 reference
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 19901-10-2021, Petroleum and natural gas industries — Specific requirements for offshore structures.
There are no normative references in this document.
3 Terms and definitions
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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:
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— — ISO Online browsing platform: available at https://www.iso.org/obphttps://www.iso.org/obp
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— — IEC Electropedia: available at https://www.electropedia.org/https://www.electropedia.org/
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3.1 3.1
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uncrewed marine vehicle
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fully automated vehicle capable of navigating on the surface or underwater according to a predefined mission numbers
by means of satellite or underwater positioning and its own sensors
[SOURCE: ISO/TS 23860:2022, 3.1.9]
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3.2 3.2
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seafloor mapping
numbers
measurement and analysis of seafloor relief patterns and features
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3.3 3.3
numbers
mean sea level
MSL
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average level of the surface of the sea over all stages of tide and seasonal variations
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Note 1 to entry: Mean sea level in a local context normally means mean sea level for the region calculated from
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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
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of note 1 to entry have been deleted.]
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3.4 3.4
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global navigation satellite system
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GNSS
satellite based navigation system that provides autonomous global positioning of a receiving device
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Note 1 to entry: See[SOURCE: ISO ISO 19901-10:2021, 3.41., modified — note 1 to entry has been deleted.]
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3.5 3.5
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ultra-short baseline acoustic positioning system
USBL acoustic positioning system
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underwater sound positioning system in which an array of acoustic transducers is deployed on a support ship
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and transducers are all built into a single transceiver assembly
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[SOURCE: ISO 5411:2024, 3.6.10]
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3.6
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3.6
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long baseline acoustic positioning system
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LBL acoustic positioning system
underwater sound positioning system which consists of a number of acoustic transponder beacons moored in
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fixed locations on the seabed or mounted on fixed locations of objects such as a support ship
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[SOURCE: ISO 5411:2024, 3.6.11]
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3.7
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real time kinematic positioning
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RTK
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the application of surveying to correct for common errors in current GNSS (3.4)global navigation satellite
system (3.4)
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3.8
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aone pulse per second
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1PPS
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1PPS is a precise time marker that emits a pulse every second.
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Note 1 to entry: 1PPS signals are output by some GNSSglobal navigation satellite system (3.4) receivers and used for
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precise timekeeping and time measurement
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Note 1 to entry: See ISO 19901-10-2021.
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2 © ISO #### 2026 – All rights reserved
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3.9 3.9
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outlier
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data pointspoint in multibeam bathymetry that significantly deviatedeviates from the true seafloor depth or
from surrounding soundings.
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Note 1 to entry: Such points typically arise from noise, unfavorableunfavourable beam geometry, water-column
numbers
disturbances, mismatched sound-speed profiles, or motion-sensor errors.
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4 Requirements
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4 Technical provisions
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4.1 General Formatted: English (United Kingdom)
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Seafloor mapping with an uncrewed marine vehicle includes field survey design, USV and UUV preparation,
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parameter setting, bathymetric survey and data processing.
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4.2 Standard of time and space
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numbers
4.2.1 Geographic coordinate system
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[5]
The World Geodetic System 1984 (WGS84)) coordinate system should be adopted.
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The mean sea level should be adopted.
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4.2.3 Standard of time
Coordinated Universal Time (UTC) should be adopted.
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4.2.4 Projection
— Grid positions should be referenced to the Universal Transverse Mercator (UTM) grid for areas
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between latitudes 80° South and 84° North.
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— For regions beyond the above range, within the polar areas, the Universal Polar Stereographic
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(UPS) projection should be used.
+ 2.8 cm + 3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3
cm + 7 cm
4.3 Accuracy requirements
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4.3 Measurement accuracy
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4.3.1 Navigation and positioning
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GNSS and a ship’s compass are recommended for surface navigation and positioning. The following
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requirements should be met:recommendations apply.
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a) a) An independent satellite positioning system isshould be available.
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b) b) The effective range of positioning and correction signals should cover the entire survey area. Formatted: Font: 11 pt
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c) c) The positioning error of the satellite differential system should not exceed 1,0 m.
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4.3.1.2 Underwater navigation and positioning
GNSS, ultra-short baseline (USBL) or long baseline (LBL) acoustic positioning systems are recommended for
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use in underwater navigation and positioning. The following requirements should be met:recommendations
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apply.
a) a) Horizontal positioning error should not exceed 5,0 m, or 1,0 m when using real-time satellite
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differentiation. b, c, … + Start at: 1 + Alignment: Left + Aligned at: 0
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b) b) Positioning accuracy of USBL acoustic positioning systems should be bettersmaller than 0,5 % Asian text, Adjust space between Asian text and
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of slant distance . numbers, Tab stops: Not at 0.7 cm + 1.4 cm + 2.1 cm
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c) c) Positioning accuracy of LBL acoustic positioning systems should be bettersmaller than 10,0 m. cm + 7 cm
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
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application and operational requirement.
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— For hydrographic surveys supporting nautical charting, navigation safety, or other official
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[5][6]
hydrographic purposes, IHO S-44, Edition 6.2.0, Standards for Hydrographic Surveys is recommended.
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— For offshore engineering, subsea construction, inspection, or other industrial survey activities,
numbers, Tab stops: Not at 0.7 cm + 1.4 cm + 2.1 cm
[6][7]
IMCA S-003, Guidelines for The Use of Multibeam Echosounders for Offshore Surveys is recommended.
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cm + 7 cm
4.3.3 Sound velocity profile (SVP) measurement
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Requirements forFor SVP measurement should be as follows:, the following recommendations apply.
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a) a) Measurement accuracy is bettershould be smaller than 0,5 m/s.
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b) b) Working depth of the SVP system exceedsshould exceed the maximum water depth of the
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survey area.
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c) c) SVP measurement should comply with project planning requirements specified by project
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d) d) SVP measurement should be evenly distributed throughout the survey area, and the time and
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location of the measurement should be recorded.
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e) e) The number of SVPs should be increased under special hydrographic conditions, such as
shallow water or estuarine areas.
f) f) SVP measurement should be conducted prior to surveying, and repeated after typhoons, storm
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surges or other strong weather events affecting the survey area.
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g) g) The measured SVPs should be used to calibrate the echo sounder.
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4.3.4 Height of tide measurement
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— Height of tide should be measured using a tide gauge station. The measurement accuracy
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should be better than 5 cm, and the time accuracy should be better than 1 min.
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— When the height of tide in the survey area cannot be measured using a tide gauge station, GNSS
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should be used to calculate the height of tide .
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4.4 Seafloor survey operation planning
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4.4.1 Survey method
— A USV or UUV equipped with survey instruments should be used.
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— The survey should be conducted in a line-measuring network or a full-coverage mapping
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approach, as required by the project objectives. + 2.8 cm + 3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3
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4.4.2 Survey mission line planning
Requirements forFor survey mission line planning should be as follows:, the following recommendations
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apply.
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a) a) Survey using a USV : Formatted: Numbered + Level: 1 + Numbering Style: a,
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1) — for full-coverage surveys, survey lines should be laid parallel to the isobath of the survey area, cm + Indent at: 0 cm, Adjust space between Latin and
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with an overlap of approximately 10 % of the effective data swaths (data meeting the 95 %
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uncertainty level). );
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cm + 7 cm
2) — for network surveys, the main survey line should be laid perpendicular to the isobath of the
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survey area.;
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b) b) Survey using a UUV:
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1) — for full-coverage surveys, the main survey line should be laid parallel to the isobath of the
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survey area or perpendicular to the prevailing current direction, an overlap of approximately 10 %
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of the effective data swa
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