ISO/IEC 24770:2012

INTERNATIONAL ISO/IEC
STANDARD 24770
First edition
2012-12-01
Information technology — Real-time
locating system (RTLS) device
performance test methods — Test
methods for air interface communication
at 2,4 GHz
Technologies de l'information — Système de localisation en temps réel
(RTLS) méthodes dispositif de performance du test — Méthodes
d'essai pour l'interface de communication de l'air à 2,4 GHz

Reference number
©
ISO/IEC 2012
©  ISO/IEC 2012
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ii © ISO/IEC 2012 – All rights reserved

Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members of
ISO or IEC participate in the development of International Standards through technical committees
established by the respective organization to deal with particular fields of technical activity. ISO and IEC
technical committees collaborate in fields of mutual interest. Other international organizations, governmental
and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information
technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of the joint technical committee is to prepare International Standards. Draft International
Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as
an International Standard requires approval by at least 75 % of the national 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/IEC 24770 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 31, Automatic identification and data capture techniques.
ISO/IEC 24770 cancels and replaces ISO/IEC TR 24770:2008.
© ISO/IEC 2012 – All rights reserved iii

Introduction
ISO/IEC 24730 defines the air interfaces and an application programming interface for Real Time Locating
Systems (RTLS) devices used in asset management applications.
This International Standard provides test methods for measuring performance of equipment compliant with
ISO/IEC 24730-2.
ISO/IEC 24769 contains all measurements required to be made on a product in order to establish whether it
conforms to the corresponding part of ISO/IEC 24730.

iv © ISO/IEC 2012 – All rights reserved

INTERNATIONAL STANDARD ISO/IEC 24770:2012(E)

Information technology — Real-time locating system (RTLS)
device performance test methods — Test methods for air
interface communication at 2,4 GHz
1 Scope
This International Standard defines the test methods for determining the performance characteristics of
2,4 GHz real time locating system (RTLS) equipment including tags, readers, and exciters which are
applicable to the selection of equipment that conforms to ISO/IEC 24730-2 for specific applications. This
International Standard does not apply to the testing in relation to regulatory or similar requirements.
The RTLS equipment performance parameters included in this International Standard include the mandatory
direct sequence spread spectrum (DSSS) 2,4 GHz radio frequency beacon link between tags and readers. It
includes the optional on–off keyed/frequency shift keyed (OOK/FSK) short range radio frequency link between
tags and programmers. It also includes the optional magnetic air-interface between exciters and tags and
between programmers and tags.
Unless otherwise specified, the tests in this International Standard apply exclusively to RTLS equipment
defined in ISO/IEC 24730-2.
2 Normative references
The following referenced documents are indispensable for the application 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/IEC 24730-2:2006, Information technology — Real-time locating systems (RTLS) — Part 2: 2,4 GHz air
interface protocol
ISO/IEC 19762-1, Information technology — Automatic identification and data capture (AIDC) techniques —
Harmonized vocabulary — Part 1: General terms relating to AIDC
ISO/IEC 19762-3, Information technology — Automatic identification and data capture (AIDC) techniques —
Harmonized vocabulary — Part 3: Radio frequency identification (RFID)
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC 19762-1 and ISO/IEC 19762-3
apply.
3.2 Abbreviated terms
ARB arbitrary waveform generator
BPSK binary phase shift keying
© ISO/IEC 2012 – All rights reserved 1

DSSS direct sequence spread spectrum
DUT device under test
EIRP effective isotropic radiated power
EVM error vector magnitude
FSK frequency shift keying
OOK on-off keying
PPM parts per million
RBW resolution bandwidth
RTLS real time location system
TIB timed interval blink
VBW video bandwidth
4 General
4.1 Performance requirements
This International Standard specifies a series of tests to determine the performance characteristics of RTLS
equipment relative to the ISO/IEC 24730-2 air interfaces. The results of these tests can be used to determine
the suitability of RTLS equipment for applications.
4.1.1 Location accuracy
The primary function of RTLS equipment is to locate tags within the area covered by the readers. Location
accuracy determines the primary performance criteria of an RTLS. Location accuracy can be characterized by
comparing the system's calculated location for a given set of tags to the actual location of the tags. The
system must be able to locate tags to within the applications allowable error.
4.1.2 Tag capacity
A RTLS must typically locate a large number of tags. The number of tag blinks per second that can be
processed and located through the readers can be used to determine a systems tag capacity. The system
must be able to provide location information for an applications peak tag blink density.
4.1.3 Location latency
The latency between when the tag blink is transmitted and when the RTLS equipment can provide accurate
location information determines the suitability of the equipment for the application.
4.1.4 Tag orientation
The ability of an RTLS to provide real time location information should be independent of the orientation of the
tag. The location reported by the RTLS should not change as the tag is rotated in any orientation relative to
the readers.
2 © ISO/IEC 2012 – All rights reserved

4.1.5 System range and packet error rates
The range of the tag-reader 2,4 GHz DSSS link determines the reader density requirements and also effects
system capacity. The packet error rate will determine how often the equipment can successfully provide
accurate location information for the tag.
The range, packet error rate, and orientation requirements of the optional air interfaces between the tags and
exciters, and between the tags and programmers, determine the usability of the system in meeting the
applications requirements.
4.2 Default conditions applicable to the test methods
These conditions apply to all tests.
4.2.1 Test environment
Testing shall take place in an environment typical to that of the desired application. Testing can be performed
indoors or outdoors with temperature and humidity profiles similar to that expected in the desired application.
The RF noise floor at the test location should also represent typical conditions expected within the desired
application.
4.2.2 Default tolerance
Unless otherwise specified, a default tolerance of  5 % shall be applied to the quantity values given to specify
the characteristics of the test equipment and the test method procedures.
4.2.3 System Logging
The RTLS should provide sufficient data logging to allow determination of the number of packets received and
sent, but this is not absolutely required.
5 Performance tests for ISO/IEC 24730-2
5.1 System locate performance
This subclause includes tests for location performance.
5.1.1 Test objective
The objective of this test is evaluate the system locate performance characteristics of the ISO/IEC 24730-2
equipment.
5.1.2 Test set up
The readers shall be connected to omni-directional antennas. It is preferred that the RTLS locate performance
characteristics be evaluated with the system installed as it would for the desired application. If that is not
possible, then the equipment shall be configured as shown in Figure 1, with four readers at the corners of a
square measuring 300 m across the diagonal (outdoor applications) or 200 m across the diagonal (indoor
applications). In addition to standalone tags, several tags mounted on the application's locatable assets (or
items of comparable size and composition) shall be used to evaluate locate performance.
© ISO/IEC 2012 – All rights reserved 3

Reader Reader
Tags
Reader Reader
Figure 1 — Setup of equipment for RTLS locate accuracy test
5.1.3 Test procedure
The tag shall be configured to transmit 72-bit DSSS blinks as defined in ISO/IEC 24730-2:2006, 6.3.2.2.
Unless otherwise indicated, the tags shall be configured at a blink interval such that the number of tags in the
test divided by the blink interval used during test is equal to or greater than the planned number of assets
tagged in the application (within range of a given set of readers) divided by the planned blink interval of
application tags. Each blink shall be configured with at least two sub-blinks. The tag shall be configured to
transmit at the extremes of class 1 power: 0 dBm and +10 dBm EIRP. The tag shall be attached to assets
such as to reproduce the conditions of the desired application. Additional procedures specific to individual test
are outlines in the test measurement and requirements.
5.1.4 Test measurements and requirements
5.1.4.1 Location accuracy
Tags, or sets of tags shall be distributed throughout the area of coverage at about a 20 m spacing as shown in
Figure 2. The actual location of all tags shall be recorded. The test shall be run long enough to capture a
minimum of 250 tag blinks from each tag. This will typically be several hours minimum. The total number of
tag locates calculated during the test shall be divided by expected number of blinks from all the tags included
in the test for the duration of the test using the formula: [(N tags) * (test duration)/(tag blink interval)]. Each
location calculation shall be compared to appropriate tag's actual location to produce the location error. The
location accuracy shall be represented as a percentage of all locations calculated by the system in which the
errors fall within the specified maximum error divided by the total number of locations calculated. The radius of
acceptable error shall be determined by the requirements of the application.
4 © ISO/IEC 2012 – All rights reserved

300 m
...