ISO/PAS 25091

ISO PAS/DPAS 25091:####(X)
ISO/TC 31/WG 10
Secretariat: ANSI
Date: 2025-0308-20
Angular Sweepsweep test Methodsmethods for radio frequency
identification (RFID) enabled tyres

WD stage
Warning for WDs and CDs
This document is not an ISO International Standard. It is distributed for review and comment. It is subject to
change without notice and may not be referred to as an International Standard.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of
which they are aware and to provide supporting documentation.

A model document of an International Standard (the Model International Standard) is available at:

© ISO #### – All rights reserved

ISO #####-#:####(X)
2 © ISO #### – All rights reserved

ISO PAS/DPAS 25091:####(X:(en)
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
may be reproduced 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 ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
EmailE-mail: copyright@iso.org
Website: www.iso.orgwww.iso.org
Published in Switzerland
© ISO PAS 25091 2025 – All rights reserved
iii
ISO #####-#:####(X/DPAS 25091:(en)
Contents
Foreword . Error! Bookmark not defined.
Introduction . Error! Bookmark not defined.
1 Scope . Error! Bookmark not defined.
2 Normative references . Error! Bookmark not defined.
3 Terms and definitions . Error! Bookmark not defined.
4 Angular sweep methods(ASM) . Error! Bookmark not defined.
4.1 Technical scope . Error! Bookmark not defined.
4.2 General operating conditions . Error! Bookmark not defined.
4.3 Angular exploration . Error! Bookmark not defined.
4.4 Tag position on the radio frequency identification (RFID) enabled tyreError! Bookmark not
defined.
4.5 Considerations of the wheel and the immediate surroundings of the tyreError! Bookmark not
defined.
4.6 Measuring distance . Error! Bookmark not defined.
4.7 Angular sweep method (ASM) A . Error! Bookmark not defined.
4.8 Angular sweep method (ASM) B . Error! Bookmark not defined.
(informative) Angular sweep method (ASM) test report for radio frequency identification
(RFID) enabled tyres . Error! Bookmark not defined.
(informative) Angular sweep performance (ASP) indicator calculation . Error! Bookmark not
defined.
(informative) Angular sweep method (ASM) exploratory applications . Error! Bookmark not
defined.
Bibliography . Error! Bookmark not defined.

© ISO #### 2025 – All rights reserved
iv
ISO PAS/DPAS 25091:####(X:(en)
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.
The procedures used to develop this document and those intended for 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 documentsdocument 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 31 Tyres, rims and valves.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
© ISO PAS 25091 2025 – All rights reserved
v
ISO #####-#:####(X/DPAS 25091:(en)
Introduction
This document defines a methodology for approaching Read Range"read range" specifications in the domain
of radio frequency identification (RFID) enabled tyre applications and use cases.
The technical field relates to the capacity to control the communication link between a passive RFID tyre tag
in the ultra high frequency (UHF) RFID band from 860 to 930 MHz, and the corresponding RFID reader set at
a location where a communication transaction is expected.
The following context elements can support the need for defining such a methodology:
— RFID tags can potentially be implemented into tyres through different means and at different locations, as
described in ISO 20911;
— RFID Reader Configurationsreader configurations can be diverse along the whole tyre life cycle in terms
of tyre and antenna relative position, antenna count and technology, distance, orientation, and in terms of
relative movement between the tyre and the antenna(s);
— the concept of controlling the RFID enabled tyre design such a way that every tyre would produceproduces
a similar spatial read range response, for every tyre model, size, and for all the tyre brands, is unrealistic
since the typical tyre materials and constructions must differ for controlling a variety of product
functionalities, thus potentially modifying the three-dimensional tyre radio frequency signature. Although
a certain variability of this radio frequency signature between RFID enabled tyre models must be
acknowledged as part of the state of the art, it remains important to be able to define, measure, and control
it so the industry participants can assess their respective targets with a common approach:.
— aA tyre manufacturer would need tocan set minimum Read Rangeread range levels for its tyre model
designs and tyres in production. How this target should be formulated?
— a Read PointA read point provider wouldcan want to know how to select a representative RFID
enabled tyre sample so to configure the Read Pointread point design and setup;.
— a Read PointA read point owner wouldcan want to set requirements implying the above parties. What
common language should be used so all the parties understand each other?
— Asas the technology is ramping up within the industry, while onboarding many participants among the
technology or solution providers, Read Pointread point owners and tyre manufacturers, all looking for the
adequate specifications; it can be perceived as a strong need for:
— providing clarity during the specification discussions between the participants;
— better guiding the design and setup of Read Pointread point configurations.
This document describes a so-called an angular sweep performance (ASP (Angular Sweep Performance)
indicator) which ambition is, intended to embrace a significantly increased set of Read Pointread point
configurations when compared to the only Stand-Alonestand-alone tyre described in ISO 20912. It is
acknowledged that an increased complexity is created through the introduction of one new but major angular
parameter which is intended to open the road to a simplification of the specification approaches on Read
Rangesread ranges and provide with an answer for more common use cases.
The performance indicator is used on a broad category of RFID read points, in order to:
— predict if one specific RFID enabled tyre can successfully pass onto a given pre-defined read point
configuration;
© ISO #### 2025 – All rights reserved
vi
ISO PAS/DPAS 25091:####(X:(en)
— select a representative RFID enabled tyre sample for designing or setting up a new read point.
Methods described in ISO 20912 allow conformance verification on the minimum read range requirement
providedspecified in ISO 20909, while the Angular Sweep PerformanceASP indicator and the corresponding
ASM Methodsmethods described in PAS 25091this document allow read range specification construction on
a variety of Read Pointread point applications.
During the development of this document, attention was paid on the key parameters influencing the test
results based on the state of knowledge and practice of the contributing participants. were taken into
consideration. However, othersother parameters remain unspecified. Therefore, a testing lab maycan set
those parameters to their discretion to perform the method.
This document does not set the actual Read Rangeread range requirement targets for the corresponding Read
Pointsread points, neither it does for the RFID enabled tyres.
The associated ASM method is proposed at two 2 levels of definition, so morethat experience can be gained
and shared within the industry. An International Standard couldcan be initiated at a later stage, when the
participants have gained more experience and have identified ways to optimize and improve.
© ISO PAS 25091 2025 – All rights reserved
vii
Angular Sweepsweep test Methods for methods for radio
frequency identification (RFID) enabled tyres
1 Scope
The document definesspecifies an overall Read Rangeread range performance indicator and its
associated measurement methods for radio frequency identification (RFID) enabled tyres
described in ISO 20911 and tagged in ISO 20909.
The ultra high frequency(UHF) RFID band used covers from 860 to 930 MHz. Methods
applyapplying to passenger cars, light commercial and truck vehicles classes of tyres as defined in
subclause 4.1clause 4.1. .
Performance indicator is to be used on a broad category of RFID Read Points so to:
- predict if one specific RFID enabled tyre can successfully pass onto a given pre-defined
Read Point configuration;
- select a representative RFID enabled tyre sample for designing or setting up a new Read
Point.
Methods described have not been investigated for tyres beyond tyre classes defined in
subclause 4.1clause 4.1.
2 Normative references
The 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 the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
ISO 20912, Conformance test methods for RFID enabled tyres
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
3.1
ASP
angular sweep performance indicator
EIRPminASP
minimum effective isotropic radiated power threshold (EIRPMin) value set at a reference distance
of 1 meter and at athe best angular orientation
3.2
antenna reference point
physical extremity of an antenna
© ISO #### 2025 – All rights reserved
DRAFT - ISO PAS 25091
Note 1 to entry: Antenna The antenna reference point contributes to setting the actual measurement
distance.
3.3 RSSI
received signal strength indicator
RSSI
indicative, non-calibrated value of the received power at the reader input
Note 1 to entry: This is the power backscattered by the tag towards the reader and measured at the reader
input. RSSI is sometimes used to determine a tag's distance, as the signal is stronger from a tag that is closer
to the reader antenna, however, the reflections and attenuation due to different materials maycan distort
it.
[SOURCE: ISO 20912:2020], clause , 3.4]
3.4
read point configuration
system configuration designed for operating either a transaction and/or communication, or both,
between the RFID tag and the reader
Note 1 to entry: Key read point configuration parameters described in the scope of this document belong to
the positioning and the relative movement between the RFID enabled tyre and the antenna(s).
3.5 EIRP
equivalent isotropic radiated power
EIRP
product of the power supplied to the antenna and the maximum antenna gain in one direction
relative to an isotropic radiator (absolute or isotropic gain)
[ISO 20912:2020], clause 3.6
3.6
EIRPMin
[SOURCE: ISO 20912:2020, 3.6, modified — Term changed from "effective isotropic radiated
power" to "equivalent isotropic radiated power", formula deleted and Note 1 to entry deleted.]
3.6
minimum effective isotropic radiated power threshold
EIRPMin
minimum power emitted by the isotropic antenna from the E-field required for the tag to turn-on
Note 1 to entry: It is generated at a selected measuring distance and at a selected frequency.
3.7
3.83.7 Pt
minimum reader power threshold
Note 1 to entry: Minimum reader power threshold Pt
is the power set at the reader level which corresponds to EIRPMin. It
© ISO PAS 25091 2025 – All rights reserved
Note 1 to entry: The Pt is obtained at a selected measuring distance and at a selected frequency considering
the specific laboratory equipment as far as cabling and antenna.
3.9
stand-alone tyre
static and non-mounted tyre
3.123.8
anechoic chamber
test chamber where radio waves are not reflected inside and not transmitted from outside
Note 1 to entry: An anechoic chamber is a room designed for operating radio frequency tests without
reflections from the delimiting surfaces in the frequency bands of interest. It is additionally equipped with
a Faraday cage system preventing radio frequency emissions from travelling through the boundaries of the
room. An operator would typically conductconducts the test from the outside of the chamber.
3.133.9
class of tyre
type of tyres intended to be used on similar vehicles
Note 1 to entry: The relevant types of class of tyre are named and defined as follows:
— — passenger car tyre: tyres conforming to ISO 4000-1;
— — light commercial vehicle tyre and truck tyres conforming to ISO 4209-1 and identified by a load
index in single configuration lower or equal to 121 and speed symbol higher or equal to “N”.
4 ASM testAngular sweep methods(ASM)
4.1 Technical scope
The performanceASP indicator (ASP) determined through the Angular Sweep test Methods (ASM)
is preferably suited for addressing the performance requirements combining tyres from the class
of tyres (3.10) and Read Pointsread points characterized by key features such as:
— individual tyres (not stacked or not too close from neighborsneighbours);
— antenna(s) facing the tyre side where the tag is located;
— tag/antenna(s) relative movement including linear displacement and/or rotation and/or
rolling;
— unmounted and wheel mounted tyres;
— unmounted and vehicle mounted tyres.
Other more complex Read Pointread point featured configurations such as “stacked tyres”, “tag
and antenna on opposite sides of the tyre”, “tag situated on the inner tyre in dual tyres
configuration” and other possible configurations beyond these here mentioned may also be
explored through this performance indicator and associated measurement methods but would
need more precautions at the date of publication of the documentmust be taken.
© ISO #### 2025 – All rights reserved
DRAFT - ISO PAS 25091
See Annex CAnnex C for an exploratory adaptation of ASM methods in the scope of more complex
Read Pointsread points.
4.2 General operating conditions
The method applies specific requirements described in ISO 20912 for the following domains:
— testing sites: corresponding to the “Semi-Anechoic Chambersemi-anechoic chamber”
description in clause ISO 20912:2020, 4.2.2;
— lab test equipment: as described in clause ISO 20912:2020, 4.3.3. Complementary guidelines
are also described in Annex BAnnex B;;
— general precautions and requirements described in clauses ISO 20912:2020, 4.1.2.2 and 4.2.2,
which are associated to:
— radio frequency regulations in the geographical zone of operation;
— electromagnetic interferences avoidance;
— tyre stand;
— radio Frequency Absorbersfrequency absorbers;
— operator position when applicable;
— radio wave reflection control i.e.; ;
— distances control from ceiling and floor.
The Testing Sitetesting site may optionally be upgraded to an Anechoic Chamberanechoic chamber,
which provides:
— a greater flexibility on radio frequency bands and maximum reader power explorations;
— an improved repeatability of the measurements while cancelling external radio frequency
interferences and internal reflections.
4.3 Angular exploration
4.3.1 Introduction
The concept of implementing an angular sweep around the tyre to identify the best available read
range potential maycan suggest that a spatial exploration is required.must be conducted. But,
considering the dipole characteristics of the tag solutions, it is a reasonable assumption to limit
the spatial exploration to a plane which is perpendicular to the direction of the tag antenna and
passing through the centercentre of the tag, where the max radiation is expected.
© ISO PAS 25091 2025 – All rights reserved
Due to the Read Pointread point features preferably covered by the measuring method (see 4.1
4.1),), the plane exploration is limited to the 180° window facing the tagged main surface of the
RFID enabled tyre.
4.3.2 Angular sweep specification
The Testing Areatesting area shall have an equipment allowing an angular exploration around the
RFID enabled tyre, while ensuring a constant measuring distance. Such equipment may be
constituted of one or a combination of the following configurations:
— turn table supporting the tyre stand associated to a fixed antenna;
— static tyre stand associated to a turning antenna;
— static tyre stand associated to several static antennas.
Such equipment should comply withconform to the following requirements when applicable:
— supporting the tyre stand and the tyre in static mode or while rotating in between
measurements;
— supporting the antenna in static mode or while rotating in between measurements;
— remaining parallel to the floor while rotating so the impact on the measuring distance remains
in control per the recommendation provided in clause 4.6clause 4.6;;
— allowing to generate angle steps while remaining static during measurements at a set angle;
— remaining neutral on radio wave reflections and radio interferences in line with the
recommendations of 4.24.2.
The angular sweep system maycan optionally use devices such as distance sensors and/or
intersecting laser beams (or similar systems) so to align the tag axis with the measuring system
axis while ensuring the alignment remains stable at any relevant angle step.
4.4 Tag position on the radio frequency identification (RFID) enabled Tyretyre
The position and axis of the tag shall be identified and marked onto the outer surface of the RFID
enabled tyre so to facilitate alignment of the tag axis with the angular sweep system axis.
The tag may be located by applying different methods such as:
— the tag position is provided as a technical specification along with the tyre;
— the tag is visible on the surface of the tyre;
— the tag is located through an X-ray of the tyre;
— a max RSSI search is made with a reader as described in clause 4.1.2.2 of ISO 20912:2020,
4.1.2.2.
The appropriate method may be selected while considering the impact on accuracy control
described in subclause 4.6clause 4.6 and as a function of the RFID enabled tyre configuration.
© ISO #### 2025 – All rights reserved
DRAFT - ISO PAS 25091
When the tag is located, the RFID enabled tyre outer surface should be marked with a straight
visible segment reproducing the identified tag position barycenter (dot marking) and the antenna
main axis (segment marking).
For an easier implementation during the following steps, it may be assumed that the tag is placed
on the outer surface of the tyre, and at the marking location. Such an assumption has negligible
impact for the preferred tyre categories addressed through this measuring method description
since the tag maycan be at a depth in a range of a few centimeterscentimetres at most. This
recommendation does not prevent from operating with a technictechnique able to account for the
exact axis and tag location.
The tag axis shall be aligned with the angular sweep system axis while bringing the tag barycenter
in plane with the angular sweep measuring plane. The angular offset between the tag axis and the
sweep plane perpendicular line (a) shall remain inferior to 10°, while the tag barycenter position
shall be controlled through the measuring distance specification in subclause 4.6clause 4.6.
Figure 1
Figure 1 describes examples of configurations of tag axis and tag barycenter with the
corresponding angular sweep measuring plane.
(a) line: Tag axis is perpendicular to the Angular Sweep Plane

(b) & (c) lines pass through the tag barycenter and form the Angular Sweep Plane

© ISO PAS 25091 2025 – All rights reserved
Key
a line: tag axis is perpendicular to the angular sweep plane
b and c lines pass through the tag barycenter and form the angular sweep plane
Figure: 1 — Angular Sweep Measuring Planesweep measuring plane
4.5 Considerations of the wheel and the immediate surroundings of the tyre
When a wheel is projected to belong to the read point application and when its specific
quantitative impact on the measurement outcome cannot be estimated upfront:
— the wheel may be included in the method and the RFID enabled tyre correspondingly wheel
mounted on a similar wheel model (geometry, materials);
— the tyre may be sufficiently inflated so the contact zone between the rim and the tyre is
established while not exceeding the maximum authorized pressure;
— a recommended test pressure shall be requested to the tyre manufacturer.
Other variable parameters such as: vehicle, ground, conveyor parts, ambient conditions
fluctuation are known to belong to certain Read Pointsread point configurations but are not
parameters included in the test method.
4.6 Measuring Distancedistance
The measuring distance is defined by the length of the segment joining the antenna reference
point to the tag barycenter, or if applicable, to its marked representation on the outer surface of
the tyre.
The measuring distance shall be set in the range from 0.,50 m to 1.,50 m.
The recommended measuring distance is 1.,0 m.
For the measuring distance a tolerance of +/-±0.,02 m shall be ensured while exploring the
measuring angular window.
The geometrical setup shall ensure the measurement segment remains inside a fixed virtual
cylinder of 0,05m05 m radius and having an axis parallel to the floor which passes by the static
© ISO #### 2025 – All rights reserved
DRAFT - ISO PAS 25091
extremity (antenna reference point or tag barycenter), while exploring the measuring angular
window. This fluctuation maycan be generated by any default of parallelism of the turning systems
and/or out of plane set up when several antennas are used.

NOTE: When the specified minimum measuring distance does not provide enough valid
measurement outputs for a significant set of RFIDs enabled tyres, it may be considered to operate
in an Anechoic Chamberanechoic chamber so to be able to exploit a maximum reader power which
goes beyond local regulation limits. When a measuring distance reduction is selected, it shall not
be smaller than 0.5m,5 m and the tolerances shall be kept as defined above.

NOTE: When the tyre is mounted on a wheel during the test, a specific attention should be provided
so to remain into the far field operating conditions and the measuring distance should be adjusted
accordingly within the above specification.
4.7 Angular Sweep Method -sweep method (ASM) A
4.7.1 General
This method may be applied as a minimum requirement for characterizing the RFID Enabled
Tyreenabled tyre with an angular exploration of 5 angle steps.
4.7.2 Method layout
A general setup is presented in Figure 2Figure 2 and Figure 3Figure 3 in a similar context as for the
Semi-Anechoic Chambersemi-anechoic chamber described in clause 4.2.2 of ISO 20912:2020, 4.2.2.
The method layout consists of 5 different angular positions (orientations between the tyre-tag
and the antenna) which can be obtained through one of the following options (as described in
subclause 4.3.2clause 4.3.2):):
— turn table supporting the tyre stand associated to a fixed antenna;
— or static tyre stand associated to 5 static antennas having same reader’s antenna gain 𝐺𝐺 and
𝐴𝐴
same cable loss 𝐿𝐿 ;;
𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐𝑐
— or static tyre stand associated to a turning antenna.
NOTE : A possible application of 4.44.4 is to ensure the antenna positions around a fixed tyre are all in
plane and parallel to the floor while targeting the tag barycenter.

© ISO PAS 25091 2025 – All rights reserved
Figure 2: ASM-A Method Layout – Side view

Key
d measuring distance
h height vs the ground
1 .n antenna positions
2 reader
3 RFID enabled tyre
4 ground
Key
5 anechoic panels (e.g.,
d measuring
electromagnetic frequency
windowsdistance
absorbers)
6 tyre stand
8 tag axis
9 tyre/tag/antenna horizontal
axis
11 Figure 2 — ASM A
layout — Side view
© ISO #### 2025 – All rights reserved
DRAFT - ISO PAS/DPAS 25091:(en)

1 antenna positions
3 RFID enabled tyre
4 ground
5 anechoic panels (e.g., elec
...