1、BS ISO 6420:2016Hydrometry Position fixingequipment for hydrometricboatsBSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06BS ISO 6420:2016 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 6420:2016. The UK participation in its prep
2、aration was entrusted to Technical Committee CPI/113/1, Hydrometric methods and instrumentation.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are respons
3、ible for its correct application. The British Standards Institution 2016.Published by BSI Standards Limited 2016ISBN 978 0 580 89720 7 ICS 17.120.20 Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standar
4、ds Policy and Strategy Committee on 31 October 2016.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS ISO 6420:2016 ISO 2016Hydrometry Position fixing equipment for hydrometric boatsHydromtrie Systme de positionnement pour embarcation hydromtriquesINTERNATIONAL STANDARDISO
5、6420Second edition2016-10-01Reference numberISO 6420:2016(E)BS ISO 6420:2016ISO 6420:2016(E)ii ISO 2016 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2016, Published in SwitzerlandAll rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwi
6、se 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 ISOs member body in the country of the requester.ISO copyright officeCh.
7、de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 6420:2016ISO 6420:2016(E)Foreword ivIntroduction v1 Scope . 12 Normative references 13 Terms and definitions . 14 Requirements for position fixing 15 Position fixing e
8、quipment for streamgauging and sediment sampling 15.1 General . 15.2 Tapes and tag lines. 25.3 Global navigation satellite systems . 25.3.1 General 25.3.2 Hydrometric application . 35.3.3 System specifications . 35.4 Targets and electronic distance measuring equipment . 35.4.1 General 35.4.2 Targets
9、 35.4.3 Electronic distance measuring devices 35.5 Electronic survey instruments 45.6 Theodolites . 45.6.1 Theodolites and stadia 45.6.2 Angular technique 46 Position fixing equipment for morphological surveys 56.1 General . 56.2 Global navigation satellite systems . 56.3 Electronic surveying instru
10、ments 56.4 Theodolites and stadia rods 67 Uncertainty . 67.1 Definition of uncertainty 67.2 Uncertainty of position fixing for streamgauging and sediment sampling 77.2.1 General 77.2.2 Tag lines . 77.2.3 Global navigation satellite systems 77.2.4 Targets and distance measuring devices 87.2.5 Electro
11、nic surveying instruments . 87.2.6 Theodolites . 87.3 Uncertainty of position fixing for morphological surveys . 87.3.1 General 87.3.2 Global navigation satellite systems 97.3.3 Electronic surveying instruments . 97.3.4 Triangulation method using theodolites . 9Annex A (informative) Evaluation of un
12、certainty components .10Bibliography .12 ISO 2016 All rights reserved iiiContents PageBS ISO 6420:2016ISO 6420:2016(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Stand
13、ards 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 ta
14、ke 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 pa
15、rticular the different approval criteria needed for the different types of ISO documents 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).Attention is drawn to the possibility that some of the elements of
16、 this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see
17、www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to
18、the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html .The committee responsible for this document is Technical Committee ISO/TC 113, Hydrometry, Subcommittee SC 5, Instruments, equipment and data management.This s
19、econd edition of ISO 6420 cancels and replaces ISO 6420:1984, which has been technically revised. The following major changes have been made: information on the use of global navigation satellite systems has been added; the former Annexes A and B have been removed; the treatment of uncertainty has b
20、een expanded and aligned with ISO/TS 25377.iv ISO 2016 All rights reservedBS ISO 6420:2016ISO 6420:2016(E)IntroductionThe necessity of positioning hydrometric boats arises in several types of measurements on open channels or lakes, reservoirs and estuaries. First, it is necessary to position a boat
21、on a measuring section in order to conduct the appropriate observations of velocity and depth for a discharge measurement. Position fixing also is required for collecting suspended sediment and bedload samples at appropriate verticals on a river cross section. Similarly, positioning of a boat is nee
22、ded for morphological surveys and sediment sampling of lakes, reservoirs and estuaries.This document provides information for positioning hydrometric boats with various methods ranging from standard surveying equipment to navigation systems employing signals from the constellation of satellites. ISO
23、 2016 All rights reserved vBS ISO 6420:2016BS ISO 6420:2016Hydrometry Position fixing equipment for hydrometric boats1 ScopeThis document specifies methods of determining the position of hydrometric boats based on satellite navigation systems and/or with respect to known points on the banks of river
24、s, estuaries or lakes. It applies to electronic positioning equipment and conventional surveying techniques.2 Normative referencesThe 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
25、the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 748, Hydrometry Measurement of liquid flow in open channels using current-meters or floats3 Terms and definitionsFor the purpose of this document, the terms and def
26、initions given in ISO 772 apply.ISO and IEC maintain terminological databases for use in standardization at the following addresses: ISO Online browsing platform: available at http:/www.iso.org/obp IEC Electropedia: available at http:/www.electropedia.org/4 Requirements for position fixingThe necess
27、ity of using position fixing equipment arises in two types of measurements on open channels or lakes, reservoirs and estuaries.First, it is necessary to position a boat on a measuring section in order to conduct the appropriate observations of velocity and depth for a discharge measurement (as speci
28、fied in ISO 748). The use of acoustic Doppler current profilers for making discharge measurements (see ISO/TR 24578) has largely diminished the need for position fixing equipment for hydrometric boats when making discharge measurements. However, there are still some types of measurements when vertic
29、als on a cross section have to be positioned for velocity and depth determinations. Position fixing also is required for collecting suspended sediment and bedload samples at appropriate verticals.The second type of measurements requiring position fixing are morphological surveys of lakes, reservoirs
30、 and estuaries. Position fixing is required to determine the positions at which depth observations and bottom samples are obtained.5 Position fixing equipment for streamgauging and sediment sampling5.1 GeneralThere are different types of position-fixing equipment. This clause describes the following
31、: measuring tapes, tag lines, global navigation satellite systems (GNSS), a combination of targets and electronic distance measuring equipment, electronic surveying equipment, and theodolites and stadia rods.INTERNATIONAL STANDARD ISO 6420:2016(E) ISO 2016 All rights reserved 1BS ISO 6420:2016ISO 64
32、20:2016(E)5.2 Tapes and tag linesTapes and tag lines are the most frequently used means for width measurements when measuring rivers by boat or wading. Steel measuring tapes with markings at metres and 10thsof metres (or 100thsof meters) are used in streams and rivers less than 50 m wide. A typical
33、tag line consists of a marked corrosion-resistant steel cable that is 2 mm to 3 mm in diameter. The diameter of the tag line depends on the width of the channel, the velocity of the water and whether or not the same tag line is used for holding the boat and for determining its position. Larger diame
34、ter tag lines may be needed if used for dual purposes. Tag lines are typically marked at intervals of 5 m to 10 m with double markings at 50 m and 100 m. Tag lines are commonly used on channels up to 300 m wide, however, the accuracy of the distance measurements depends on cable tension. Long tag li
35、nes are usually wound on a drum having a diameter of at least 0,3 m and equipped with a cranking and braking mechanism.Caution should be used when tapes and tag lines are used to position hydrometric boats on navigable rivers. An observer on the river bank should be available to alert the hydrograph
36、ers of approaching boats and also alert boat operators of the tape or tag line. Other operators may be required to temporarily remove the tape or tag line to allow boat passage through the measuring section.5.3 Global navigation satellite systems5.3.1 GeneralNavigation systems that use GNSS technolo
37、gy are used on larger rivers that are too wide for stringing a tagline. These systems provide reliable location and time information, in all weather conditions and at all times, anywhere on or near the Earth when and where there is an unobstructed line of sight to four or more satellites in the cons
38、tellation of satellites.There are two operational GNSS. The NAVSTAR Global Positioning System (GPS) was developed by the U. S. Department of Defense; it is composed of 24 satellites. GLONASS was developed by the Soviet Union and is operated by the Russian Aerospace Defense Forces; it also is compose
39、d of 24 satellites. Other global or regional systems under development include Galileo being developed by the European Union, Compass being developed by China, and IRNSS, a regional system being developed by India.There are two general operating methods by which satellite-derived positions can be ob
40、tained; either absolute point positioning or relative (differential) positioning. a) With absolute point positioning, measurements of the distance to each individual satellite are made by analysing the time it takes for a signal to travel from a satellite to the antenna of the navigation system. Tri
41、lateration is then used to establish the receivers position. The accuracy of the position is about 3 m or less.6 b) Differential positioning is the technique or method used to position one point relative to another. Differential positioning requires a ground station within line of sight distance of
42、20 km or less. Differential positioning can provide a relative accuracy of a few centimetres.5Receivers with real-time kinematic (RTK) technology can provide a relative accuracy of 1 cm to 2 cm. RTK uses a similar set-up to differential positioning, but with two significant differences: the RTK sign
43、al is evaluated for timing error (not just the information contained within the signal), and the error correction is transmitted immediately to the GNSS units resulting in real time accuracy. Some RTK-enabled receivers are able to use satellite-broadcasted corrections and provide very accurate posit
44、ioning over much longer distances. There is an added cost of using broadcasted corrections from private satellites.GNSS technology uses the World Geodetic System 1984 (WGS84) as the default datum. Other earth models or coordinate reference systems may be desired for specialized applications, such as
45、 for high-resolution mapping and navigation in specific regions of the Earth.7 The use of any preferred local 2 ISO 2016 All rights reservedBS ISO 6420:2016ISO 6420:2016(E)coordinate reference systems in such applications requires a suitable coordinate transformation from WGS84.75.3.2 Hydrometric ap
46、plicationSatellite navigation systems allow operators to preselect transects and verticals for making depth and velocity determinations. The systems consist of a receiver, navigation software, and a digital display that shows the position of the boat on the cross section. Navigation systems facilita
47、te the measurement of depth and velocity or the collection of samples at verticals with only a boat operator and one hydrographer.5.3.3 System specificationsThere are a wide range of navigation systems that can be used for hydrometric applications. Systems should have the following minimum capabilit
48、ies for positioning boats on river cross sections: ability to receive signals from more than one global or regional satellite navigation system and ground reference stations; sufficient channels to receive signals for up to 12 satellites; water proof or resistant so electronics will not be damaged d
49、uring rain or spray from waves; a digital display that shows the boat position, cross section and waypoints (verticals); a sunlight mode so the system can be operated in direct sunlight; ability to store 100 or more waypoints (verticals); an alarm system to indicate when the boat drifts from the cross section or designated waypoint (vertical); output function for transferring position information to a discharge measurement application.5.4 Targets and electronic distance measuring equipment5.4.1 GeneralTargets are used to
