ISO 12188-1:2010

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

ISO 12188-1:2010 provides a procedure for evaluating and reporting the accuracy of navigation data determined using positioning devices that are based on GPS, GLONASS, Galileo or similar global navigation satellite systems (GNSS). It focuses on the performance of the positioning devices while they are subject to motions typical of ground-based agricultural field operations and specifies common performance parameters that can be used to quantify and compare the dynamic performance of different positioning devices.

Tracteurs et matériels agricoles et forestiers — Modes opératoires d'essai des systèmes de positionnement et de guidage utilisés en agriculture — Partie 1: Essai dynamique des dispositifs de positionnement par satellite

General Information

• Status: Published
• Publication Date: 02-Mar-2010
• ICS: 35.240.99 - IT applications in other fields
• ICS: 65.060.01 - Agricultural machines and equipment in general
• Technical Committee: ISO/TC 23/SC 19 - Agricultural electronics
• Drafting Committee: ISO/TC 23/SC 19 - Agricultural electronics
• Current Stage: 9093 - International Standard confirmed
• Start Date: 07-Jun-2021
• Completion Date: 13-Dec-2025

Overview - ISO 12188-1:2010 (Dynamic testing of satellite-based positioning devices)

ISO 12188-1:2010 specifies test procedures for evaluating and reporting the dynamic performance of satellite-based positioning devices (PDs) used on tractors and agricultural/forestry machinery. Focused on GNSS technologies (GPS, GLONASS, Galileo and similar), the standard defines how to measure navigation data (position, course, speed, latency) while receivers are subjected to motions typical of field operations. It establishes common performance parameters to quantify and compare dynamic positioning accuracy for precision agriculture and machine guidance.

Key topics and technical requirements

• Scope and intent
  • Dynamic testing of GNSS-based positioning devices during realistic ground motion.
  • Quantification of absolute/relative positioning accuracy, course-over-ground, speed and latency.
• Test course geometry and environment
  • Course must include at least two straight segments (≥ 90 m) and a 180° U-turn (radius 5–10 m).
  • Straight segments oriented between 35° and 55° from true north; elevation change ≤ 1 m.
  • No obstructions >10° above horizontal; avoid metallic surfaces within 50 m to reduce multipath.
• Test runs and speeds
  • Test runs conducted in 1 h blocks at fixed speeds: (0.1 ± 0.05) m/s, (2.5 ± 0.2) m/s and (5.0 ± 0.2) m/s.
  • Each speed/direction combination is tested four times (24 runs total) completed within 25 h.
• Initialization, settings and logging
  • PDs reset to defaults before initialization; manufacturer’s recommended initialization time is used and reported.
  • NDRs logged at maximum PD rate and must include date/time, position, elevation, geoidal separation, speed, course-over-ground, satellite count, correction status and constellation.
• Reference navigation system (RNS)
  • RNS must be at least an order-of-magnitude (10×) more accurate than the tested PD and synchronized with PD outputs.
• Dynamic signal reacquisition test
  • Simulated signal outages during the U-turn (using metal housing or ≥60 dB attenuator) at 1.0 m/s to evaluate reacquisition and NDR recovery.
• Reporting and analysis
  • Provide signed/unsigned error distributions, median/95%/maximum errors, bias analysis, and metadata (satellite parameters, HDOP, solar activity/sunspot number).
  • Distance/error calculations per Annex A to avoid projection biases.

Applications - who uses ISO 12188-1:2010

• GNSS receiver manufacturers and firmware developers (device validation and product claims)
• Agricultural OEMs and auto-guidance system integrators (performance verification)
• Independent test laboratories and certification bodies (conformance testing)
• Agricultural researchers and precision farming consultants (comparative studies)
• Procurement and specification writers (objective selection criteria for positioning devices)

Related standards

• ISO 12188 (series) - Part 2 (auto-guidance testing during straight and level travel) noted as under preparation.
• NMEA 0183 referenced for definitions such as course-over-ground and time/UTC formatting.

Keywords: ISO 12188-1:2010, GNSS, satellite-based positioning, dynamic testing, precision agriculture, positioning accuracy, course-over-ground, latency, signal reacquisition.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 12188-1
First edition
2010-03-15
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
Tracteurs et matériels agricoles et forestiers — Modes opératoires
d'essai des systèmes de positionnement et de guidage utilisés en
agriculture —
Partie 1: Essai dynamique des dispositifs de positionnement par
satellite
Reference number
©
ISO 2010
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ii © ISO 2010 – All rights reserved

Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Terms and definitions .1
2.1 General terms related to positioning device testing .1
2.2 Terms describing position accuracy and error measurements .2
3 Requirements.3
3.1 General .3
3.2 Horizontal positioning test .4
3.3 Dynamic signal reacquisition test .4
4 Calculations and report .4
4.1 General .4
4.2 Positioning accuracies .5
4.3 Course-over-ground accuracy .6
4.4 Course latency.6
4.5 Speed accuracy .6
4.6 Latency .6
Annex A (normative) Error and accuracy computation .7
Bibliography.8

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 12188-1 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
The following parts are under preparation:
⎯ Part 2: Satellite-based auto-guidance systems tested during straight and level travel
iv © ISO 2010 – All rights reserved

Introduction
Satellite positioning devices have become more common in agricultural applications. They are not only used
as position sensors for georeferencing data or site-specific application tasks, but are also part of more
complex navigation systems for agricultural machines.
In the early stages of development of this part of ISO 12188, the only existing standards for satellite-based,
positioning-device performance specification focused on the static accuracy of the device. There was no
existing standard that adequately specified methods for testing or reporting the accuracy of the receivers while
they are in motion. This part of ISO 12188 is intended to fill this void by providing a framework for testing
receivers that are subject to the type of motion typically experienced by receivers used in agricultural field
operations. It provides an implementable methodology for conducting the tests while still providing a means to
equitably compare the performance of different satellite-based positioning devices.

INTERNATIONAL STANDARD ISO 12188-1:2010(E)

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
1 Scope
This part of ISO 12188 provides a procedure for evaluating and reporting the accuracy of navigation data
determined using positioning devices that are based on GPS, GLONASS, Galileo or similar global navigation
satellite systems (GNSS). It focuses on the performance of the positioning devices while they are subject to
motions typical of ground-based agricultural field operations and specifies common performance parameters
that can be used to quantify and compare the dynamic performance of different positioning devices.
2 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
2.1 General terms related to positioning device testing
2.1.1
positioning device
PD
instrument that is capable of determining and reporting the position of its antenna centre point in geographic
coordinates and in real time using satellite-based radio-navigation signals
2.1.2
navigation data record
NDR
report of geographic coordinates, elevation, course, travel velocity and other navigation-related parameters
computed by a PD
2.1.3
travel course
TC
predefined route of travel during the test
2.1.4
reference navigation system
RNS
fixture or measurement device capable of either precisely controlling the path of the PD or recording the actual
path that the PD traversed
2.1.5
geographic coordinates
geographic latitude, longitude and elevation with respect to an internationally defined geodetic coordinate
system
2.1.6
travel speed
distance travelled in a unit of time
NOTE Travel speed is expressed in metres per second.
2.1.7
course over ground
horizontally projected direction of travel measured clockwise from true north, as defined by NMEA 0183
NOTE The projected direction of travel is expressed in degrees.
2.1.8
time
Universal Time Coordinated (UTC) with corresponding date, as defined by NMEA 0183
2.1.9
initialization time
time elapsed between the point in time when the positioning device is powered and the beginning of the first
test run
2.2 Terms describing position accuracy and error measurements
2.2.1
off-track error
perpendicular deviation from the actual travel course
2.2.2
horizontal position error
horizontally projected deviation from absolute position
NOTE This measurement does not include positioning device latency.
2.2.3
vertical position error
vertically projected deviation from absolute position
2.2.4
latency
time between reception of satellite signals at the antenna and transmission of the first character or message of
the NDR
2.2.5
absolute horizontal [vertical] positioning accuracy
extent to which an NDR conforms to RNS data
2.2.6
relative horizontal [vertical] positioning accuracy
extent to which an NDR conforms to other NDRs from the same PD at the same location at different times
2.2.7
short-term dynamic accuracy
short-term dynamic performance determined from off-track errors along straight segment passes occurring
within a 15 min time frame
NOTE Short-term dynamic accuracy is similar to what is commonly called pass-to-pass accuracy.
2 © ISO 2010 – All rights reserved

2.2.8
long-term dynamic accuracy
dynamic performance determined from off-track errors along straight segment passes occurring within a time
period of not less than 24 h
2.2.9
U-turn accuracy
dynamic performance determined from off-track errors occurring during traverse of a 180° turn
3 Requirements
3.1 General
The following applies for testing.
a) The travel course (TC) shall include at least two straight segments and a U-turn segment. The straight
segments shall be at least 90 m long and shall be oriented between 35° and 55° from true north. The
U-turn shall traverse 180° at a constant radius of turn between 5 m and 10 m and shall connect directly at
either end to straight segments. The course shall have a change in elevation no greater than 1 m. There
shall be no obstructions visible from any point on the test course, at an elevation of the PD antennae
higher than 10° above a horizontal horizon, that interfere with or block satellite signals. There shall be no
metallic or other surfaces within 50 m of the course that could cause multipath interference. Course
location and geometry shall be documented with appropriate detail to allow exact replication.
b) Before the i
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