ISO 12188-2:2012

INTERNATIONAL ISO
STANDARD 12188-2
First edition
2012-09-15
Tractors and machinery for
agriculture and forestry — Test
procedures for positioning and
guidance systems in agriculture —
Part 2:
Testing of satellite-based auto-guidance
systems during straight and level travel
Tracteurs et matériels agricoles et forestiers — Modes opératoires
d’essai des systèmes de positionnement et de guidage utilisés en
agriculture —
Partie 2: Essai des systèmes d’autoguidage satellitaires lors de
déplacements droits et horizontaux
Reference number
©
ISO 2012
© ISO 2012
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any
means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the
address below or ISO’s member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2012 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Terms and definitions . 1
2.1 General terms . 1
2.2 Error terms . 2
3 Test description . 2
3.1 Surface conditions . 2
3.2 Test course location . 2
3.3 Test course . 3
3.4 Determination of RVP relevant position . 3
3.5 Vehicle selection . 3
3.6 Test preparation . 3
3.7 Test procedure . 3
4 Test report and calculations . 4
4.1 Test report generation . 4
4.2 AGS performance and error report . 5
Bibliography . 6
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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International
Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies
casting a vote.
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.
ISO 12188-2 was prepared by Technical Committee ISO/TC 23, Tractors and machinery for agriculture
and forestry, Subcommittee SC 19, Agricultural electronics.
ISO 12188 consists of the following parts, under the general title Tractors and machinery for agriculture
and forestry — Test procedures for positioning and guidance systems in agriculture:
— Part 1: Dynamic testing of satellite-based positioning devices
— Part 2: Testing of satellite-based auto-guidance systems during straight and level travel
iv © ISO 2012 – All rights reserved

Introduction
This part of ISO 12188 provides detailed information for the dynamic testing of satellite based positioning
devices or complex navigation systems (automatic steering systems) used in agriculture. The dynamic
testing relies on metering geographic positioning quality when tested devices and systems are in motion
resembling their use in agriculture. Various professionals need comparable and detailed information
on the behaviour of such systems based on standardised test procedures. Potential users include
developers and manufacturers of agricultural equipment and positioning or navigation components as
well as farmers or other end users.
INTERNATIONAL STANDARD ISO 12188-2:2012(E)
Tractors and machinery for agriculture and forestry —
Test procedures for positioning and guidance systems in
agriculture —
Part 2:
Testing of satellite-based auto-guidance systems during
straight and level travel
1 Scope
This part of the ISO 12188 specifies the process for evaluating and reporting the performance of
agricultural vehicles equipped with automated guidance systems (AGS) based on a global navigation
satellite system (GNSS) when operating in an automatic steering mode.
The main performance criterion is the lateral deviation of a representative point on the vehicle from a
desired trajectory for that point. This performance criterion integrates the uncertainties associated with
the performance of all components of the vehicle guidance system including the positioning device(s),
automated steering components, and vehicle mechanisms and dynamics.
This part of ISO 12188 focuses on steady-state tracking performance of the automated guidance system
while travelling on straight paths over a level surface.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1 General terms
2.1.1
positioning device
PD
instrument that is capable of determining and reporting the position of its antenna center point in
geographic coordinates and in real time using satellite-based radio-navigation signals
2.1.2
differential correction
means of accounting for predictable geographic positioning errors in real time
2.1.3
automatically guided vehicle system
AGVS
AGS-equipped agricultural vehicle
2.1.4
representative vehicle point
RVP
fixed point relative to a vehicle or implement used to represent the location of the AGVS
2.1.5
test course
repeatable route of travel comprised of one or more test course segments typical of an agricultural
field operation
2.1.6
test course segment
clearly defined continuous part of the test course that is used to estimate tracking errors of the AGVS
2.1.7
tracking sensor
instrument or instrument system designed to produce horizontal distance measurements required for
error calculations that are at least ten times more accurate than the accuracy of the AGVS being tested
2.1.8
test run
one complete passage along the test course in one direction of travel
2.1.9
complete test
combination of several identical test runs performed at different times
2.1.10
A–B line
imaginary line passing through two arbitrary selected locations (A and B) used by most automated
guidance systems to establish field traffic geometry
2.1.11
operator
individual operating or monitoring the AGVS being tested
2.2 Error terms
2.2.1
relative cross-track error
XTE
lateral deviation of the RVP from the desired path determined from previous paths of the RVP when
guided along the same test course
2.2.2
revisit time
time elapsed between two RVP position recording events used to calculate relative XTE; e.g.,
measurements made in the same location along a test course during two different test runs
2.2.3
pass-to-pass error
anticipated short-term XTE with less than 15 min revisit time
2.2.4
long-term guidance error
anticipated XTE with a revisit time greater than 1 h
3 Test description
3.1 Surface conditions
The test course shall be established on a concrete pavement surface. Alternative surface conditions, e.g.,
agricultural field surfaces, may also be test
...