1、BS ISO 6420:2016 Hydrometry Position fixing equipment for hydrometric boats BSI Standards Publication WB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06BS ISO 6420:2016 BRITISH STANDARD National foreword This British Standard is the UK implementation of ISO 6420:2016. The UK participation in i
2、ts preparation 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 ar
3、e responsible for its correct application. The British Standards Institution 2016. Published by BSI Standards Limited 2016 ISBN 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
4、 the Standards Policy and Strategy Committee on 31 October 2016. Amendments/corrigenda issued since publication Date T e x t a f f e c t e dBS ISO 6420:2016 ISO 2016 Hydrometry Position fixing equipment for hydrometric boats Hydromtrie Systme de positionnement pour embarcation hydromtriques INTERNAT
5、IONAL STANDARD ISO 6420 Second edition 2016-10-01 Reference number ISO 6420:2016(E)BS ISO 6420:2016ISO 6420:2016(E)ii ISO 2016 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2016, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be repro
6、duced 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 ISOs member body in the country of the requester
7、. ISO copyright office Ch. de Blandonnet 8 CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyrightiso.org www.iso.orgBS ISO 6420:2016ISO 6420:2016(E)Foreword iv Introduction v 1 Scope . 1 2 Normative references 1 3 Terms and definitions . 1 4 Requirements for
8、 position fixing 1 5 Position fixing equipment for streamgauging and sediment sampling 1 5.1 General . 1 5.2 Tapes and tag lines. 2 5.3 Global navigation satellite systems . 2 5.3.1 General 2 5.3.2 Hydrometric application . 3 5.3.3 System specifications . 3 5.4 Targets and electronic distance measur
9、ing equipment . 3 5.4.1 General 3 5.4.2 Targets 3 5.4.3 Electronic distance measuring devices 3 5.5 Electronic survey instruments 4 5.6 Theodolites . 4 5.6.1 Theodolites and stadia . . 4 5.6.2 Angular technique 4 6 Position fixing equipment for morphological surveys 5 6.1 General . 5 6.2 Global navi
10、gation satellite systems . 5 6.3 Electronic surveying instruments 5 6.4 Theodolites and stadia rods 6 7 Uncertainty . 6 7.1 Definition of uncertainty 6 7.2 Uncertainty of position fixing for streamgauging and sediment sampling 7 7.2.1 General 7 7.2.2 Tag lines . 7 7.2.3 Global navigation satellite s
11、ystems 7 7.2.4 Targets and distance measuring devices 8 7.2.5 Electronic surveying instruments . 8 7.2.6 Theodolites . 8 7.3 Uncertainty of position fixing for morphological surveys . 8 7.3.1 General 8 7.3.2 Global navigation satellite systems 9 7.3.3 Electronic surveying instruments . 9 7.3.4 Trian
12、gulation method using theodolites . 9 Annex A (informative) Evaluation of uncertainty components .10 Bibliography .12 ISO 2016 All rights reserved iii Contents PageBS ISO 6420:2016ISO 6420:2016(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national
13、 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. Internationa
14、l 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 f
15、or 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 documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.o
16、rg/directives). Attention is drawn to the possibility that some of the elements of 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 b
17、e in the Introduction and/or on the ISO list of patent declarations received (see 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 expressio
18、ns related to conformit y assessment, as well as information about ISOs adherence to 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
19、 113, Hydrometry, Subcommittee SC 5, Instruments, equipment and data management. This second 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
20、added; the former Annexes A and B have been removed; the treatment of uncertainty has been expanded and aligned with ISO/TS 25377.iv ISO 2016 All rights reservedBS ISO 6420:2016ISO 6420:2016(E) Introduction The necessity of positioning hydrometric boats arises in several types of measurements on ope
21、n 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. Position fixing also is required for collecting suspended sediment and bedload samples a
22、t appropriate verticals on a river cross section. Similarly, positioning of a boat is needed 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 e
23、quipment to navigation systems employing signals from the constellation of satellites. ISO 2016 All rights reserved vBS ISO 6420:2016BS ISO 6420:2016Hydrometry Position fixing equipment for hydrometric boats 1 Scope This document specifies methods of determining the position of hydrometric boats bas
24、ed on satellite navigation systems and/or with respect to known points on the banks of rivers, estuaries or lakes. It applies to electronic positioning equipment and conventional surveying techniques. 2 Normative references The following documents are referred to in the text in such a way that some
25、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 748, Hydrometry Measurement of liquid flow in open channels using cur
26、rent-meters or floats 3 Terms and definitions For the purpose of this document, the terms and definitions 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 IE
27、C Electropedia: available at http:/ /www.electropedia.org/ 4 Requirements for position fixing The necessity 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
28、order to conduct the appropriate observations of velocity and depth for a discharge measurement (as specified 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
29、boats when making discharge measurements. However, there are still some types of measurements when verticals 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
30、. The second type of measurements requiring position fixing are morphological surveys of lakes, reservoirs 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 sam
31、pling 5.1 General There are different types of position-fixing equipment. This clause describes the following: measuring tapes, tag lines, global navigation satellite systems (GNSS), a combination of targets and electronic distance measuring equipment, electronic surveying equipment, and theodolites
32、 and stadia rods. INTERNATIONAL ST ANDARD ISO 6420:2016(E) ISO 2016 All rights reserved 1BS ISO 6420:2016ISO 6420:2016(E) 5.2 Tapes and tag lines Tapes and tag lines are the most frequently used means for width measurements when measuring rivers by boat or wading. Steel measuring tapes with markings
33、 at metres and 10 thsof metres (or 100 thsof meters) are used in streams and rivers less than 50 m wide. A typical 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 wat
34、er and whether or not the same tag line is used for holding the boat and for determining its position. Larger diameter 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
35、channels up to 300 m wide, however, the accuracy of the distance measurements depends on cable tension. Long tag lines 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 posit
36、ion hydrometric boats on navigable rivers. An observer on the river bank should be available to alert the hydrographers 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
37、 the measuring section. 5.3 Global navigation satellite systems 5.3.1 General Navigation systems that use GNSS technology 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, any
38、where on or near the Earth when and where there is an unobstructed line of sight to four or more satellites in the constellation 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 satellite
39、s. GLONASS was developed by the Soviet Union and is operated by the Russian Aerospace Defense Forces; it also is composed 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 regiona
40、l system being developed by India. There are two general operating methods by which satellite-derived positions can be obtained; either absolute point positioning or relative (differential) positioning. a) With absolute point positioning, measurements of the distance to each individual satellite are
41、 made by analysing the time it takes for a signal to travel from a satellite to the antenna of the navigation system. Trilateration 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 po
42、sition one point relative to another. Differential positioning requires a ground station within line of sight distance of 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 accurac
43、y of 1 cm to 2 cm. RTK uses a similar set-up to differential positioning, but with two significant differences: the RTK signal 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
44、 time accuracy. Some RTK-enabled receivers are able to use satellite-broadcasted corrections and provide very accurate positioning 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)
45、as the default datum. Other earth models or coordinate reference systems may be desired for specialized applications, such as 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)
46、coordinate reference systems in such applications requires a suitable coordinate transformation from WGS84. 7 5.3.2 Hydrometric application Satellite navigation systems allow operators to preselect transects and verticals for making depth and velocity determinations. The systems consist of a receive
47、r, navigation software, and a digital display that shows the position of the boat on the cross section. Navigation systems facilitate 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 specifications There are
48、a wide range of navigation systems that can be used for hydrometric applications. Systems should have the following minimum capabilities for positioning boats on river cross sections: ability to receive signals from more than one global or regional satellite navigation system and ground reference st
49、ations; sufficient channels to receive signals for up to 12 satellites; water proof or resistant so electronics will not be damaged during 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 po
