ISO/PAS 25091:2026

Publicly
Available
Specification
ISO/PAS 25091
First edition
Angular sweep test methods for
2026-03
radio frequency identification
(RFID) enabled tyres
Méthodes d'essai par balayage angulaire des pneus équipés de la
technologie d'identification par radio fréquence (RFID)
Reference number
© ISO 2026
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Angular sweep methods (ASM) . 2
4.1 Technical scope .2
4.2 General operating conditions .3
4.3 Angular exploration .3
4.3.1 Introduction .3
4.3.2 Angular sweep specification .4
4.4 Tag position on the radio frequency identification (RFID) enabled tyre .4
4.5 Considerations of the wheel and the immediate surroundings of the tyre .5
4.6 Measuring distance .5
4.7 Angular sweep method (ASM) A .6
4.7.1 General .6
4.7.2 Method layout .6
4.7.3 Angular data points .8
4.7.4 Measuring process .8
4.8 Angular sweep method (ASM) B .9
4.8.1 General .9
4.8.2 Method layout .9
4.8.3 Angular window .10
4.8.4 Measuring process . 12
Annex A (informative) Angular sweep method (ASM) test report for radio frequency
identification (RFID) enabled tyres . 14
Annex B (informative) Angular sweep performance (ASP) indicator calculation .16
Annex C (informative) Angular sweep method (ASM) exploratory applications .20
Bibliography .22

iii
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
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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 document 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
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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.

iv
Introduction
This document defines a methodology for approaching "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 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 produces 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.
— A tyre manufacturer can set minimum read range levels for its tyre model designs and tyres in
production. How this target should be formulated?
— A read point provider can want to know how to select a representative RFID enabled tyre sample so
to configure the read point design and setup.
— A read point owner can want to set requirements implying the above parties. What common language
should be used so all the parties understand each other?
— as the technology is ramping up within the industry, while onboarding many participants among the
technology or solution providers, read 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 point configurations.
This document describes an angular sweep performance (ASP) indicator, intended to embrace a significantly
increased set of read point configurations when compared to the only stand-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 ranges and provide 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;
— 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
specified in ISO 20909, while the ASP indicator and the corresponding ASM methods described in this
document allow read range specification construction on a variety of read point applications.
During the development of this document, the key parameters influencing the test results based on the state
of knowledge and practice of the contributing participants were taken into consideration. However, other

v
parameters remain unspecified. Therefore, a testing lab can set those parameters to their discretion to
perform the method.
This document does not set the read range requirement targets for the corresponding read points, neither
for the RFID enabled tyres.
The associated ASM method is proposed at two levels of definition, so that experience can be gained and
shared within the industry. An International Standard can be initiated at a later stage, when the participants
have gained more experience and have identified ways to optimize and improve.

vi
Publicly Available Specification ISO/PAS 25091:2026(en)
Angular sweep test methods for radio frequency
identification (RFID) enabled tyres
1 Scope
The document specifies an overall read 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 860 to 930 MHz. Methods applying to passenger
cars, light commercial and truck vehicles classes of tyres as defined in subclause 4.1.
Methods described have not been investigated for tyres beyond tyre classes defined in subclause 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
angular sweep performance
ASP
minimum effective isotropic radiated power threshold (EIRPMin) value set at a reference distance of 1 meter
and at the best angular orientation
3.2
antenna reference point
physical extremity of an antenna
Note 1 to entry: The antenna reference point contributes to setting the actual measurement distance.
3.3
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 can distort it.
[SOURCE: ISO 20912:2020, 3.4]
3.4
read point configuration
system configuration designed for operating either a transaction or communication, or both, between the
RFID tag and the reader
Note 1 to entry: Key read point configuration parameters described in this document belong to the positioning and the
relative movement between the RFID enabled tyre and the antenna(s).
3.5
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)
[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
minimum reader power threshold
P
t
power set at the reader level which corresponds to EIRPMin
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.
3.8
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 typically
conducts the test from the outside of the chamber.
3.9
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 tyres: tyres conforming to ISO 4000-1;
— light commercial vehicle tyres and truck tyres conforming to ISO 4209-1.
4 Angular sweep methods (ASM)
4.1 Technical scope
The ASP indicator determined through the ASM is preferably suited for addressing the performance
requirements combining tyres from the class of tyres and read points characterized by key features such as:
— individual tyres (not stacked or not too close from neighbours);
— 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 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 more precautions must be taken.
See Annex C for an exploratory adaptation of ASM methods in the scope of more complex read 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 chamber” description in ISO 20912:2020, 4.3.2;
— lab test equipment: as described in ISO 20912:2020, 4.3.3. Complementary guidelines are also described
in Annex B;
— general precautions and requirements described in ISO 20912:2020, 4.2.3.3 and 4.3.2, which are
associated to:
— radio frequency regulations in the geographical zone of operation;
— electromagnetic interferences avoidance;
— tyre stand;
— radio frequency absorbers;
— operator position when applicable;
— radio wave reflection control;
— distances control from ceiling and floor.
The testing site may be upgraded to an anechoic 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 can suggest that a spatial exploration 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 centre of the tag, where
the max radiation is expected.
Due to the read point features preferably covered by the measuring method (see 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 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 conform 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 subclause 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 4.2.
The angular sweep system can 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 tyre
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 ISO 20912:2020, 4.2.3.3.
The appropriate method may be selected while considering the impact on accuracy control described in
subclause 4.6 and as a function of the RFID enabled tyre configuration.
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 can be at a
depth in a range of a few centimetres at most. This recommendation does not prevent from operating with a
technique 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 4.6.

Figure 1 describes examples of configurations of tag axis and tag barycenter with the corresponding angular
sweep measuring plane.
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 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 point configurations but are not parameters included in the test method.
4.6 Measuring distance
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
...