Stid TeleTag System User manual

Vehicle Identification
TeleTag® System
STid UHF RFID Readers
IMPLEMENTATION GUIDE

© STid 2014 –No unauthorised reproduction | Introduction
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Vehicle identification: TeleTag UHF
Introduction
The purpose of this document is to describe the approach to be used when developing a vehicle
identification project using TeleTag® technology, to ensure optimal outcomes for the required
configuration and installation conditions.
General principles of UHF technology
Operating principle
TeleTag® uses “passive” UHF (Ultra-High Frequency) technology, which means that the chip does not
require a battery to operate, because its power is supplied by the reader. In Europe, the frequency used
for this technology is 866 MHz (915 MHz in the USA).
This passive UHF technology can therefore be used to read data from an electronic tag with no integrated
power supply within a range of several metres.
Uses and limitations, environmental effects, useful information
Various laws of physics apply to this technology and can influence the way it operates. The major factors
to bear in mind are as follows:
-The materials the tag is used on or behind will influence reader performance (range and speed). A
tag should be matched to its environment to give the best possible results.
oThe same tag will operate very differently on metal or behind glass (windscreen).
oAt this frequency, radio waves do not travel well through liquids. A human body between
the reader/antenna and the tag itself could obstruct tag reading.
-Radiofrequency identification does not work through metal.
oTypical example: heat-reflective (or climate comfort) windscreens on modern vehicles
have a metallic film that blocks radio waves. Any tag that is behind this metallic screen
would not be read. However, these windscreens have non-treated areas that allow the
radio waves through.
-Radio waves emitted by the reader and the tag can bounce off obstacles and be diverted. The
presence of obstacles in the field can influence the results.
-UHF technology can be directional. Some antenna has a fairly directional “reading field”, rather
like the area lit up by a spotlight. The location of antenna will therefore need to be planned on
the basis their reading zone, depending on their characteristics.
-A UHF tag may have a specific orientation, related to the polarisation of its antenna. A “linear” tag
will be orientation-sensitive and will not read as well horizontally as it does vertically.

© STid 2014 –No unauthorised reproduction | General principles of UHF technology
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Vehicle identification: TeleTag UHF
Optimum
Given the constraints described above, it is important to identify the conditions that will give the best
possible system performance. This means ensuring the optimum antenna and tag positions.
Performance will depend on the position of the tag relative to the antenna. Maximum range and
optimised detection will be achieved if the tag is directly opposite the antenna, parallel to it, and with the
correct polarisation.
For optimum performance, the tag should be straight opposite the antenna.
The range values given in technical specifications for the readers are measured in straight-on distances,
with the tag parallel to the antenna.
When the tag is at an angle from the antenna, the effective range is reduced.
The angle in question may be a horizontal or vertical angle, depending on the comparative height of the
antenna compared to the vehicle and the lateral offset of the antenna, compared to the lane of traffic.
30° / 87%
45° / 70%
0° / 100%
Antenne
Reduced range
Nominal range

© STid 2014 –No unauthorised reproduction | Tag position
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Vehicle identification: TeleTag UHF
Tag position
Selecting the tag location
TeleTag® performance is influenced by its position on the windscreen, and depends on the windscreen
type. The aim is to position the tag to optimise the quality and performance of reading function.
For heat-reflective windscreens, it is essential to place the tag in the non-treated areas (where
applicable) as shown in the illustration below. The location of these non-treated areas will depend on
the make and model of the vehicle. A non-exhaustive list is available in the Appendix. If there isn’t non-
treated heat-reflective area, the tag won’t be read.
See Appendix: Windscreen types with location of non-treated areas.
Standard private car: the ideal position is near the top of the windscreen, behind the rear-view mirror, if
possible on the side the reader antenna is located.
Ensure the tag is not touching the upper edge of the windscreen.
Side to choose according to position of the antenna / reader

© STid 2014 –No unauthorised reproduction | Tag position
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Vehicle identification: TeleTag UHF
Heavy Goods Vehicle (HGV) / Truck / Bus
For lorries and buses, there are two possible solutions:
Tag inside vehicle on windscreen (TLT model): same positioning requirements as for a car.
Tag outside vehicle on bodywork: place the tag so it is as close to parallel as possible with the
reader antenna, in the desired reading zone.
oExample with a TML model, on a bus radiator grill: approximately 1.10m from the ground,
not touching the metal windscreen wiper
Installing the tag
Once you have decided where to position the tag, install it using the holder provided.
Using the double-sided adhesive tape provided, affix the holder horizontally on the windscreen and insert
the tag using the method of your choice:
1 –The TeleTag is removable from its holder to transfer it in an other vehicle.
2 –The TeleTag is not transferable.
When you choose the location, bear in mind the space you will need to insert the tag into the holder (look
at the angle of the windscreen).

© STid 2014 –No unauthorised reproduction | New projects
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Vehicle identification: TeleTag UHF
New projects
When considering equipping a site with a TeleTag® system, various steps need to be followed.
Site analysis
Gather the basic information required for defining the configuration:
-Site map,
-Direction of traffic,
-Vehicle sizes,
-Vehicle types to be identified
Project definition
Identification zones: define the areas in which the vehicles are to be identified
-Locations,
-Dimensions
Materials choices
Information on the project and conditions gathered in the earlier stages of analysis will feed into the
initial equipment choices: reader type, number of antenna, tag type etc.
Site requirements and constraints will determine the technical choices. This analysis will provide a good
overview of the feasibility of the desired configuration and will help to identify any adaptations or
adjustments that may be required.
Testing
From the outset, we recommend defining the tests required for validating the configuration with the
client (if validation is required). It is important to ensure that representative vehicles and the appropriate
equipment are available for the validation tests.
Installation methodology
Place the vehicle in the typical / desired identification zone
Adjust the antenna height and orientation until the tag can be read
Test the configuration with a moving vehicle
Adjust the antenna to achieve optimum results
This configuration will be optimised for the test vehicle. The set-up will ideally need to be retested
with a vehicle that is very different from the first (higher windscreen, van etc.) in order to ensure the
antenna is positioned so as to cover as wide a range of usage cases as possible.

© STid 2014 –No unauthorised reproduction | Basic installation rules
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Vehicle identification: TeleTag UHF
Basic installation rules
For a vehicle access gate, you are advised to place the antenna and set up the detection zone ahead of
the barrier for more reliable detection and to allow the system time to activate the barrier opening
system.
A higher antenna with a downward orientation will limit the ground range and therefore prevent the tag
on a second vehicle being inadvertently read.
Zone typique de détection UR1
Zone typique de détection URC / URD
Zone d’identification
typique : 0-3 m

© STid 2014 –No unauthorised reproduction | Configuration examples
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Vehicle identification: TeleTag UHF
Configuration examples
This section describes classic configurations for vehicle access gates, indicating the recommended
locations for the antenna/readers.
This configurations are only examples and do not guarantee results. They are generic, with the purpose of
feeding the design process. External variables can also influence certain functional factors.
Simple one-lane access
One URC reader in a lateral orientation
Positioned ahead of the barrier for early detection
2-3 m
Zone d’identification
typique : 0-3 m

© STid 2014 –No unauthorised reproduction | Configuration examples
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Vehicle identification: TeleTag UHF
Simple one-lane dual-height access
For use hen a single antenna is not sufficient to cover the height of both an HGV and a car.
One dual-antenna URD reader in a lateral orientation
1 antenna positioned for optimal detection of cars
1 antenna positioned for optimal detection of HGVs
Reader positioned ahead of the barrier for early detection.
Double-width access on a two-way public road
Double-width sliding gate, with vehicles arriving from both directions
Dual-antenna URD reader or 2 URC readers
One antenna either side of the gate to be aligned with each direction of travel.

© STid 2014 –No unauthorised reproduction | Configuration examples
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Vehicle identification: TeleTag UHF
Single entrance / exit gate
Use of a single URD reader / two antenna to manage a bi-directional access gate
The antennas are controlled by a single reader, to reduce any risk of interference.
Each antenna controls one lane and transmits the data it reads to the appropriate gate.
Multi-lane access
Use of a multi-antenna / multi-lane URD reader. A single reader can control 1 to 4 lanes.
The antennas are controlled by a single reader, to reduce any risk of interference.
Each antenna controls one lane and transmits the data it reads to an independent output.
The antenna cannot be further than 9m from the reader, so the reader is located in the
centre (red box).

© STid 2014 –No unauthorised reproduction | How to estimate the theoretical range
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Vehicle identification: TeleTag UHF
How to estimate the theoretical range
Aim: estimate the reading position, based on the antenna location and the vehicle position.
Note: The results given below can vary substantially depending on vehicle type, but the theory remains
valid.
Reminder: the optimal range, as expressed in the specifications, is taken with the tag straight in front and
parallel with the antenna, and at the optimum reading position.
Antennas are often positioned to one side of the traffic lane, and at a different height. A corrected range
value (Dc) is estimated from the nominal range (D) in order to give the ground range (Ds) - the ground-
level distance between tag and antenna. This distance is generally quoted as the operational range, but it
is not the straight-line distance between the tag and antenna.
Corrected Range (Dc) = Nominal Range (D) corrected by the horizontal angle and
elevation angle between the tag and antenna/reader. It is determined by the antenna
height and orientation.
Ground Range (Ds) = Corrected Range (Dc) * adjustment coefficient (based on angle Z)
STEP ONE: calculate the Corrected Range (Dc)
D
Antenne / Lecteur
TAG
Distance Nominale
Dc : Distance de lecture corrigée
Ds: Distance au sol
Ds
Dc

© STid 2014 –No unauthorised reproduction | How to estimate the theoretical range
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Vehicle identification: TeleTag UHF
=> Note: angle xshould be taken as an average, because it can differ according to vehicle model. It should
be estimated on the basis of a predefined fixed antenna height.
=> Note: angle yshould be taken as an average, because it can differ according to vehicle model and
lateral position in relation to the antenna.
This table should be used to estimate the reduction in range
due to the angles between antenna and tag (which determine
the adjustment coefficient to be applied to the nominal range
as a result of the approximate horizontal and vertical angles):
Corrected Range (Dc) = nominal range (D) * Adjustment
Coefficient (Angle x) * Adjustment coefficient (Angle y)
D1
Angle idéal
Tag parallèle à l’antenne / lecteur
Position réelle
D2
Angle idéal
Tag parallèle à l’antenne / lecteur
Position réelle
angle y
Angle X°
Adjustment Coefficient
15°
0.96
20°
0.94
25°
0.90
30°
0.87
35°
0.82
40°
0.76
45°
0.71

© STid 2014 –No unauthorised reproduction | How to estimate the theoretical range
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Vehicle identification: TeleTag UHF
Examples
Example 1: Let us consider a URC reader and TeleTag on a standard windscreen.
Nominal range: 7 m
Average angle x: 20°
Average angle y: 30°
Corrected Range (Dc) = 7* 0.94 * 0.87 = 5.72 m
Example 2: Let us consider a URC reader and TeleTag on a heat-reflective windscreen.
Nominal range: 4 m
Average angle x: 20°
Average angle y: 30°
Corrected Range (Dc) = 4* 0.94 * 0.87 = 3.27 m
STEP TWO: calculate the Ground Range (Ds)
The angle z adjustment coefficient is applied to Corrected Range (Dc) to give the Ground Range (Ds).
For example 1:
Dc = 5.72. If angle Z is 30°, then: Ds =5.72m * 0.87 = 4.97 m
For example 2:
Dc = 3.27. If angle Z is 30°, then: Ds =3.27m * 0.87 = 2.84 m
Dc : Distance de lecture corrigée
Ds: Distance au sol
Ds
Dc

© STid 2014 –No unauthorised reproduction | Heat-reflective windscreens
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Vehicle identification: TeleTag UHF
Heat-reflective windscreens
Heat-reflective concept
A heat-reflective windscreen allows the regulation of the heat inside the car. The car manufacturers use
metal leaf in the treatment of the windscreens.
We can recognize heat-reflective windscreens through the colored reflections on the glass.
Impact of the heat-reflective windscreens on the performances
The metal being a blocking element for radio frequencies, heat-reflective windscreens will modify the
performances of the reading distance. In several cases, there is a non-treated area (refer to the ANNEXE –
non-exhaustive list). This area is made for radio systems (GPS, RFID…). However, the reading distance can
be reduced.
By the way, it is very important to take into account this point before the installation of the reader and
realize the tests in order to define the location of the reader.

© STid 2014 –No unauthorised reproduction | Frequently Asked Questions
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Vehicle identification: TeleTag UHF
Frequently Asked Questions
Issue
Likely cause
Recommendation
My reader frequently reboots
Current too low
Check the cable types, power
supply and distance between
power supply and reader.
My reader does not start up
Voltage too low
Incorrect cabling
Check the voltage at the reader
input terminals.
Use a regulated power supply.
My tag is not read because I
have a heat-reflective
windscreens
Bad positioning of the tag or
reader not well placed.
Change the location of the tag
or reader.
Heat-reflective windscreens
without non-treated part
Change the positioning of the
tag or the type of it.

© STid 2014 –No unauthorised reproduction | Frequently Asked Questions
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Vehicle identification: TeleTag UHF
APPENDIX 1: Types of heat-reflective windscreens