RFID Road Info Report Final

8/13/2019 RFID Road Info Report Final

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RFID Based Road Info 2012-13

[Dept. of ECE, SCTIT] Page 1

1. INTRODUCTIONThe first disturbing fact is that RFID is not a new technology. It was first used over

sixty years ago by Britain to identify aircraft in World War II and was part of the refinement

of radar. It was during the 1960s that RFID was first considered as a solution for the

commercial world. The first commercial applications involving RFID followed during the

70s and 80s. These commercial applications were concerned with identifying some asset

inside a single location. They were based on proprietary infrastructures.

The third era of RFID started in 1998, when researchers at the Massachusetts Institute

of Technology (MIT) Auto-ID Center began to research new ways to track and identify

objects as they moved between physical locations. This research, which has a global outlook,

centered on radio frequency technology and how information that is held on tags can beeffectively scanned and shared with business partners in near real time.

To do this we needed standards. The work of the Auto-ID Center focused on:

Reducing the cost of manufacturing RFID tags. Optimizing data networks for storing and delivering larger amounts of data. Developing open standards.

It became apparent that the ideas being proposed, combined with other ongoingtechnological and standardization activities worldwide, would help to reduce the costs of

RFID tagging. By 2003, the Center had over 100 sponsors from four continents. Its final task

was to conduct a large field trial with 40 participating companies in 10 US cities. Today, the

work of the Auto-ID Center has helped to make RFID economically viable for pallet and

carton-level tagging. The technology is also becoming more affordable for high-value items.

The Auto-ID Center officially closed on October 26, 2003, transferring all its technology to

EPCglobal.

EPCglobal is now leading the development of industry-driven standards for the

Electronic Product Code (EPC) Network to support the use of Radio Frequency Identification

(RFID) in today's fast-moving, information rich trading networks. EPCglobal is a member-

driven organization composed of leading firms and industries that are focused on creating


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global standards for the EPCglobal Network. The EPCglobal Network is a set of technologies

that enable immediate, automatic identification and sharing of information on items in the

supply chain. In that way, the EPCglobal Network will make organizations more effective by

enabling true visibility of information about items in the supply chain.

Figure 1: The History of RFID

Radio Frequency Identification (RFID) technology is used in various industries for

controlling and enhancing the data. One of these fields is vehicular applications ranging from

safe navigation to Intelligent Transportation System (ITS). RFID can be used in vehicles and

highways to control the access to the vehicles, traffic and parking management. Stored

information in tags of cars, like as, serial number, driver information could be transferred to

the reader.

In dangerous region such as bridges, tunnels, and icy road, drivers might need more

useful information about the surrounding environment to avoid an unpredictable accident.

Output of this work is, creating an information service to supply necessary information to car

in foggy and poor visibility road. In the following sections, first, the proposed architecture is

described and experimental results are reported. After that, the accurate computing of car to

road margin is described.


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2.RFID ROAD INFORMATION2.1 WHAT IS THE NEED?

On average, there are over 6,301,000 vehicle crashes each year. Twenty-four (24)percent of these crashesapproximately 1,511,000are weather-related. Weather-related

crashes are defined as those crashes that occur in adverse weather (i.e., rain, sleet, snow,

and/or fog) or on slick pavement (i.e., wet pavement, snowy/slushy pavement, or icy

pavement). On average, 7,130 people are killed and over 629,000 people are injured in

weather-related crashes each year. (Source:Fourteen-year averages from 1995 to 2008

analyzed by Noblis, based on NHTSA data).

The vast majority of most weather-related crashes happen in the presence of fog, the tablebelow gives the statistics of fog related accidents.

Weather-Related Crash Statistics

Road Weather

Conditions

Annual

Rates(Approximately)

Percentages

Foggy 15,600 persons injured 1% of crash

injuries

2% of weather-

related crash

injuries

600 persons killed 1% of crash

fatalities

8% of weather-

related crash

fatalities

Table 2.1: Weather-Related Crash Statistics (Annual Averages)

RFID is the emerging new technology which will help curd these accidents.

A collision avoidance system in urban intersections can also be effectively supported

by vehicle RFID readers and lane RFID tags. A driver entering the 4-way intersection may

not have noticed a vehicle executing a left turn. In poor visibility (e.g., foggy night), this can

easily lead to an accident. If vehicles are aware of their accurate position from tags deployed

near the intersection and have announced their position via a beacon, the accident can be


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avoided. Another promising application of passive lane tags is a wrong way warning. There

are many one-way streets in downtown areas. It is important to warn drivers before a head on

collision occurs. Particularly deadly is the freeway or ramps. It is unfortunately very common

for drivers at night to enter the freeway or the ramp and drive on the wrong way in the fast

lane with consequences that are easy to imagine. As the car reads the lane RFIDs, it

immediately realizes that they are coming in the wrong sequence, that is, it is going the

wrong way! Advance wrong way warning will prevent the driver from entering the freeway.

Moreover if a vehicle notices a wrong way from RFID tag data after entry, it can

automatically broadcast an alarm messages to neighbor vehicles to alert them of the possible

collision danger.


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3.RFID BASICSRadio Frequency Identification (RFID) is a set of technologies that allow for short

range, contact-less reading of information from a low cost, compact, data source. An RFID

system will include data-carrying transponders, known as tags and devices to access the

data on the tags; a reader or reader/writer.

Tag or TransponderAn RFID tag is a tiny radio device that is also referred toas a transponder, smart tag, smart label, or radio barcode. The tag comprises a simple

silicon microchip (typically less than half a millimeter in size) attached to a small flat

aerial and mounted on a substrate. The whole device can then be encapsulated in

different materials (such as plastic) dependent upon its intended usage. The finished

tag can be attached to an object, typically an item, box, or pallet, and read remotely to

ascertain its identity, position, or state. For an active tag there will also be a battery.

Figure 3a: A variety of RFID Tags

Reader or Interrogator the readersometimes called an interrogator orscannersends and receives RF data to and from the tag via antennas. A reader may

have multiple antennas that are responsible for sending and receiving radio waves.


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Figure 3b: Examples of a Reader with Associated Electronics

Host Computerthe data acquired by the readers is then passed to a host computer,which may run specialist RFID software or middleware to filter the data and route it

to the correct application, to be processed into useful information.

Figure 3c: Basic Operations of RFID (RFID Center: Dr Carol David Daniel,

Introduction to RFID, RFID Forum December 2004, RFID Center)


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4.VEHICULAR APPLICATION OF RFIDDue to recent technology advancements, RFID readers have been proposed for

several vehicular applications ranging from safe navigation to intelligent transport. However,

one obstacle to deployment is the unpredictable read performance. An RFID reader

occasionally fails to read an RFID tag even in static circumstances, mostly due to collisions.

In a mobile vehicular environment, latency becomes the key performance factor because of

the high speed of vehicles. This is particularly true when the RFID reader is on the moving

vehicle. In this paper, we investigate RFID read latency and thus effectiveness of on-vehicles

reader installations for a wide range of speeds. First, we experimentally study the impact of

reader and tag relative positions on read errors and read rates. The results reveal the critical

factors that influence on-vehicle RFID read performance, and give us guidance to identify

and pursue directions for improvement. In vehicular applications, the RFID tag is generally

mounted on the vehicle and the reader on the roadside unit.

The vehicle is equipped with an RFID reader while the RFID tags are distributed

along the road. The vehicle now plays the data consumer role. Our proposed system falls into

this category. In the previously proposed Road Beacon System (RBS), RFID tags are buried

in the pavement and an RFID reader on a vehicle gets road information. The RBS scheme is

close to our proposal, but it does not show any experimental results. An RFID-based accurate

positioning system for vehicles was proposed where an RFID tag is assumed to have accurateposition. A vehicle with RFID reader travels over the RFID tags embedded in the road and

can update its location. If a vehicle gets accurate position from RFID tags deployed on each

lane, then lane-level navigation can be achieved on a freeway. For instance, by reviewing the

RFID vehicle readings, one can easily tell when vehicles change lanes abruptly near a

freeway exit. This happens because a driver does not have sufficient forwarding from vertical

and horizontal direction signs. This information can be helpful to the transportation

department to design better and more effective signs. Additional integration of lane RFID

readings with existing car navigator functionality, i.e. voice warning if the vehicle has

declared (through the navigator) the intention to take a particular exit, can greatly enhance

driving safety.

A collision avoidancesystem in urban intersections canal so be effectively supported

by vehicle RFID readers and lane RFID tags. A driver entering the 4-way intersection may


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not have noticed a vehicle executing a left turn. In poor visibility (e.g., foggy night), this can

easily lead to an accident. If vehicles are aware of their accurate position from tags deployed

near the intersection and have announced their position via a beacon, the accident can be

avoided. Another promising application of passive lane tags is a wrong way warning. There

are many one-way streets in downtown areas. It is important to warn drivers before a head on

collision occurs. Particularly deadly are the freeways or ramps. It is unfortunately very

common for drivers at night to enter the freeway or ramp and drive on the wrong way in the

fast lane with consequences that are easy to imagine. As the car reads the lane RFIDs, it

immediately realizes that they are coming in the wrong sequence, that is, it is going the

wrong way! Advance wrong way warning will prevent the driver from entering the freeway.

Moreover if a vehicle notices a wrong way from RFID tag data after entry, it can

automatically broadcast an alarm messages to neighbor vehicles to alert them of the possible

collision danger.

A passive RFID system is composed of a passive RFID tag storing data and an RFID

reader that accesses the tag and collects data. The RFID reader continuously emits RF radio

waves and waits for signals back from the tag. When the tag receives the radio waves, it

absorbs energy from the waves, modulates ID data, and sends information back to the reader.

This section reviews properties of an RFID system that are closely related to RFID

communication.

The necessity of external power classifies the RFID system; an active RFID tag

contains a power module, whereas a passive tag is powered by a radio wave beamed from a

reader. An operating frequency determines how energy and data is transmitted; through an

inductive coupling or a backscattering coupling. The inductive coupling uses an inductor coil

in HF and LF communication. The antenna coil in the reader generates a magnetic field in a

nearby area which gives rise to inductive power in the tag antenna. Current in the tag is so

weak, creating a very short transmission range, i.e. around several centimeters. The

modulated backscattering coupling in UHF bandwidth makes use of the fact that a

microwave is rejected by an object whose size is greater than half of the wave length. This

enables longer radio range, i.e. approximately up to 10m.

An RFID system suffers from two types of collision, namely a reader and tag

collision. The reader collision occurs when more than two RFID readers try to access one

RFID tag simultaneously. With Time Division Multiple Access (TDMA), a reader is able to


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transmit a wave only within the assigned slot. Concurrent transmission of tag data toward a

single RFID reader causes the tag collision. TDMA has also provides an anti-collision

algorithm in two approaches; ALOHA-based and binary tree-based. In a pure ALOHA

algorithm, a tag, after receiving a wave, waits for a randomly generated time period before

sending data back. Frame slotted ALOHA (FSA) divides a frame into a fixed number of

slots. Here, one frame is a time period when a reader waits for receiving data back from tags

after sending a wave out. The wave contains information on the number of slots, S, in one

frame. A tag, when receiving the wave, arbitrarily picks up a random number less than S and

transmits data only during the selected slot period. If two different tags pick the same slot by

chance, a collision occurs. Then, they try to transmit data again in the next frame. The binary

tree-based algorithm allows a reader to send a command to a tag. When a collision occurs,

the reader selects a number by looking at tag IDs causing the collision and sends the number

to tags. Then, tags whose ID is greater than the number are allowed to send data back to the

reader. The rest tags transmit data in the next round.

This paper studies feasibility of a commercial RFID system in vehicular environment

because of its cost benefit. When exploiting the on-board RFID reader system, i.e. the second

scenario. The first constraint is vehicles' high speed; can an RFID reader access an RFID tag

while driving fast? In a freeway, vehicles usually drive at faster than 100km/h. This is

different from the ATC case because vehicles get slower for safety when passing through the

toll gateway. In the new system, a vehicle should be allowed to obtain tag data without

decreasing its speed. Therefore, it is fundamental to examine that an RFID communication

can occur in fast moving situation. Chon et al. studied this issue by dropping RFID tags down

in front of a fixed RFID reader in a laboratory. They estimated that an RFID communication

can occur at the maximum speed of 165km/h. However, real world data is completely

different from the laboratory results and we investigate it in the later section.

Another constraint comes from a very short communication distance. Unlike the ATC

case, i.e. 3m~4m, the communication distance between a reader and a tag could decrease to

less than 30cm since a reader on the front bumper of a vehicle is very close to tags on the

road surface. When considering cone-shaped wave propagation, the short distance creates a

small radio area, reducing probability of successful RFID communication. In addition, the

communication area moves fast along with the on-board reader, which also increase


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one tag) and tag intervals could be also taken into account when deploying the tags. The

RFID tags would not be distributed over all the roads, but we believe that a number of tags

under an appropriate strategy can be deployed in some specific roads where accidents

frequently occur. For example, when we consider 'lane level navigation' guiding a freeway

exit to a driver in this paper, the tags can be placed only near the exit. Based on assumption

of regional deployment scenario, this study examines 2m and 5m tag intervals in a 3km-

length test road for evaluation. If we can assume that each vehicle is equipped with a GPS

device, the number of tags to be deployed is reduced dramatically. In fact, the deployment

strategy, e.g. deciding the tag numbers, is one of the biggest issues in the vehicular RFID

applications since each application demands different specification.

Table 4.1: Hardware specification of the used RFID system.

Figure 4.1: RFID system: reader, reader antenna, and tag.


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4.2 Hardware of the RFID system

We select UHF RFID system because of its long read range and low cost. Table 4.1

summarizes specification of the RFID system. The RFID reader is KIS900RE operating in

900MHz-914MHz. It supports an anti-collision algorithm with Frequency-Hopping Spread

Spectrum (FHSS) in200 kHz bandwidth. The RFID reader antenna, KIS900AE, has 60of

angle and 6dBi of gain. The EM4222 chip used in the RFID tag transmits 64bit data at

256kbps. For anti-collision, each tag waits for a random delay time, pause time, before

sending data out. The maximum pause time is 62.5ms. Figure 4.1 shows the RFID system

including a computer collecting and processing RFID data.

4.3 Software Aspect of Specification

Read Area

A previous research revealed that the angle of the used RFID reader antenna is 68,

which is a little bit wider than specification. Based on this information, we depict a RFID

read area, where reader antennas can communicate a tag to obtain data, as shown in Figure

4.3. The width (x1) and length (x2) of the area are calculated by Equation 1.

Figure 4.3: RFID read area.


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Table 4.3: Moving speed of RFID read area (time to pass over a RFID tag with h = 37:5cm

and = 45).

RFID Communication

An RFID communication is a process where an RFID reader transmits wave to an

RFID tag and then receives data back from the tag. In order to obtain RFID data, one

communication, at least, must occur between the reader and the tag in the read area. Because

the reader antenna is attached to a vehicle traveling at a high speed, the read area also travels

and encounters the fixed tags during a short time period. One communication should occur at

least once within this time period. We define RFID read latency as a time period when one

communication occurs and thus a reader successfully obtains RFID data from a tag. The read

latency is upper-bounded by vehicles' speed. In Table 4.3, we compute how fast the read area

moves from Equation 1. For comparison, the third column, i.e. measured [sec], shows results

from our experiments. The gap between 'computed' and 'measured' values is due to the

reduced length (x2) of the RFID read area in a real situation, which is around 1minstead of

1.85m. The table also indicates that the read latency should be less than 36ms at the speed of

100km/h.

Data Rate

256kbps of data rate of the RFID tag means that it takes 0.22ms to transmit 64bit tag

data. Our experiment, however, reveals that the average read latency is 38.89ms. This slow

communication mainly results from the pause time at the selected tag whose maximum value

is 62.5ms. This implies that there might be no RFID communication when a vehicle travels at


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a higher speed than 60km/h since the moving speed of the read area becomes 60ms or shorter

(Table 4.3).

Memory and Packet

The tag chip contains 64bit data memory. The most significant 2 bits are reserved, the

next 8 bits identify a company producing the tag, and the rest 54 bits including a CRC code

represent the RFID tag ID. The tag initiates a packet containing all memory data. Memory

size can increase up to 2,048 bits if the memory is user-programmable. Therefore, advanced

data manipulation can be achieved.

4.4 RFID Read Rate

In order to utilize the RFID system on roads, it must demonstrate reliable

performance at a high speed. In order to appreciate reliability of the RFID system, this paper

defines RFID read rateas a fraction of RFID tags successfully read over the total number of

tags deployed over a designated test road. When the test road is a 500m-long single lane and

tags are placed every 2m, i.e. 250 tags, 50% of read rate says that the reader obtains data

from 125 tags while driving the road. Reliability (or accuracy) is a relative value whose

requirement depends on each application. Through experiments, the paper figures out what

level of reliability the commercial RFID system can provide to the target application, i.e.

point localization.

It is clear that the RFID read rate decreases as speed becomes faster. As shown in the

previous subsections, the moving speed of the read area (36ms at 100km/h) is faster than the

average read latency measured (38.89ms). This means that the reader is likely to pass by one

tag without having one RFID communication, which would degrade reliability of the RFID

system. This is one constraint given from the selected commercial RFID system due to

62.5ms of its maximum pause time. One solution is to shorten the average read latency to

less than 36ms at 100Km/h and the other way is to enlarge the read area to decrease its

moving speed. The next section studies such enhancement. For fine-grained laboratory

experiment, we establish, without loss of generality, a target performance; an RFID system

should provide 0.5m of read distance in which one communication occurs within 18ms. This

is based on the measured moving speed and size of the read area. In the paper, two


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5.LABORATORY EXPERIMENT FOR INSTALLATIONOF RFID SYSTEM

Figure 5: Test bed: RFID system

This section discusses installation of the RFID system in a vehicular environment. At

first, we adjust the reader antenna to be mounted on a vehicle. Then, we examine an RFID

tag; in particular, tag multiplicity is taken into account for performance improvement. When

mounting a reader antenna on a vehicle, we deliberate its horizontal and vertical position. We

affix the antenna at the center of the front bumper since this position shows the minimum

error rate. With respect to the vertical position, we set h=30cm, because our experiment

indicates that20~40cm of height shows similar performance and the height of the front

bumper of the test vehicle is 30cm. RFID tags are placed at the center of each lane and on the

road surface. We build a static test set for laboratory experiments .The reader antenna is fixed

on a 30cm-heightframe and tags are aligned near the antenna on the floor. The reader,

connected to the antenna via the cable but not shown in this figure, identifies the tags

accessed within 18ms, which helps determine the read area with different pitch angles of the

antenna. The read latency to access the tags 0.5m away from the antenna is measured. The

figure represents one of the experiment settings that evaluate the yaw angle of a tag. Theantenna is adjusted to have 30 of pitch angle, and the tag, inside the black square line, has

30 of yaw angle.


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5.1 RFID Reader Antenna

Antenna Diversity

A dual RFID reader antenna is investigated to increase the RFID read rate. Figure 5.1

depicts the read areas with 18ms of read latency when one or two RFID reader antenna(s) is

mounted at the height of 30cm and the angle of 30

Figure 5.1a: Measured RFID read area (18ms read latency).

Figure 5.2b: Influence of dual RFID reader antennas.

.

When one reader antenna is mounted, the read area is 86cm in width, which is

acceptable if a user drives in the middle of a lane all the time. Otherwise, the read area may

not pass over the tags, which will make worse the RFID read rate as drawn in Figure 5.2b.

When mounting an additional reader antenna, the width is extended to 130cm with small


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decrease of the length from 80cm to 78cm. In this case, a vehicle is able to obtain RFID data

unless it changes a lane. Experiments in this paper use dual RFID reader antennas, otherwise

explicitly stated.

5.2 Posture (Pitch Angle)

Figure 5.2a: Length of RFID read area with varying pitch angles of RFID reader antennas.

Figure 5.2b: Average read latency with varying pitch angles of RFID reader antennas.

A pitch angle of the reader antenna is as much important as horizontal and vertical

position because the beam shape and direction influences substantially on the receive

sensitivity in a short-ranged RFID communication. Definition of the pitch angle is referred

from Section 4.3. The experiment measures the average read latency by varying the pitch


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angle from 0 to 70 as shown in Figure 5.2b. In some specific range of distance, 0cm~30cm

on the x-axis, the average read latency in most test cases converges to around 13ms. As the

distance point becomes further from the range area (to forward or backward direction), the

average read latency increases dramatically. As the x-axis can be considered as the length of

the read area, the figure also illustrates how the length changes with different pitch angles.

Figure 5.2a sketches the side view of the read area where one communication occurs

at least once within 18ms based on results from Figure 5.2b. It tells that 20~40 of the pitch

angles creates the longest read area within an error tolerance and out performs other angles.

In our experiment, we attach the reader antenna on the front bumper with 30 of the pitch

angle for easiness of installation.

Figure 5.2c: Yaw angle and pitch angle of RFID tag. Figure 5.2d: Average read latency

with varying pitch angles of RFID tag

(yaw angle=0degand pitch angle of

the reader antenna=30deg).

Table 5.2: Average read latency [ms] with varying yaw angle (a single RFID tag, a single

RFID reader antenna, and pitch angle = 0).

This subsection investigates a posture of an RFID tag in terms of its yaw angle and

pitch angle. Figure 5.2c describes their definition. A yaw angle is an internal angle of the tag

and the straight line drawn from the antenna to the tag.


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The average read latency when varying the yaw angle by every 30 is summarized in

Table 5.2. At 60, 90, and 120of yaw angles, there is no communication. Given that the

used reader antenna is horizontal polarization, the results are reasonable since energy

transmission is maximized with matched polarization between the reader antenna and the tag.

The rest settings of yaw angles show similar results, and thus we use 0 of yaw angle.

Definition of the pitch angle of a tag is same to that of the reader antenna as shown in

Figure 5.2c. If we can use Cat's Eye' when deploying RFID tags on roads, each tag can have

0~20 of pitch angles. For each pitch angle, we measure the average read latency and the

length of the read area, which is shown in Figure 5.2d. Results in the case of 10 and 20 are

almost same. When comparing them to the result of 0, the only distinction is the starting and

ending point of the read area. Therefore, we can conclude that the pitch angle of a tag does

not affect performance of the RFID read rate. For deployment of the RFID system, we use 0

of pitch angle.

5.3 Tag Multiplicity

An RFID tag cluster model is contrived in order to speed up the read latency. A

fundamental idea is to regard multiple tags in a cluster as one data, i.e. if a reader receives

data back first from any tag in one cluster, then we say that RFID communication occurs and

tag data is read successfully. As the number of tags increases in a cluster, at least one tag is

likely to select a short pause time, which shortens the read latency. On the other hand, more

tags may cause tag collision that deteriorates the RFID performance. The next experiment

tries to find the best cluster model.

Figure 5.3a: RFID tag cluster models. Figure 5.3b: Average read latency with

four RFID tag cluster models


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We consider four types of RFID tag clusters as shown in Figure 5.3a a tag consists of

a tag chip (a black spot at the center) and a dipole antenna. Each cluster manifests its own

characteristic in a way how to combine multiple tags in one cluster. Cluster 1 and 2 represent

horizontal and vertical integration, respectively. In the next, a space is given between two

neighboring member tags, which is expected to enhance the receive sensitivity. In Cluster 4,

the tag chips share one dipole antenna. We randomly place each cluster within the target read

distance (0.5m) and compute an average read latency after iterating the experiment.

Figure 5.3b shows the average read latency with four RFID tag cluster models with

increasing the number of the tags from 1 to 5. At first, it verifies that as a cluster includes

more tags the read latency comes to be shorter. In Cluster 2, 3, and 4, the time values go

down below 18ms when there are 2, 3, and 4 members tags. With 5 member tags,

performance gets much worse due to tag collision. Based on results, we decide to use Cluster

3 having 3 or 4 members of RFID tags since they show the best performance.

5.4 Preliminary Result

We have conducted laboratory experiments to study how to install an RFID system

on a road environment. Recall our target performance in Section 4.3, i.e. an RFID system

should provide 0.5m of read distance in which communication occurs within 18ms. Our

laboratory experiments with stationary test sets quantify that the length of the read area (read

distance) becomes 0.8m with 18ms of the read latency. The result allows us to calculate the

maximum speed at which a vehicle can read RFID data while traveling as below. This

estimation is also equivalent to the estimation in the previous research.

[ ]


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Figure 6a: Data part of tag format for proposed design

Data can be grouped in 6 categories now. The data situation and content and fields are

added up in table -6. Where a, b, c, d, e and f are binary numbers.

Table 6: Information that is stored in Data part of tag

As an example, suppose that there is a tunnel in front of car. The tags near the tunnel

have codes as Figure 6b.

Figure 6b: Content of tags when there is a tunnel in road

If there are other object in road, like as left-turn or 4-way cross, the fields B, C or D

have a binary number too.


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6.1 EXPERIMENTAL RESULTS

When the reader detects the RFID tag data, it transmits them to the monitoring system

and records them in the system. By recording the sequence of RFID tags data, the road

information, in front road are monitored in real time.

Figure 6.1, shows some types of information on monitoring package. This figure

shows an example, when reader detect from tag that there is a tunnel in front of the car with

about 60 meters, the Figure 3-f schema is shown on monitoring display. The new situation,

same as bridge in road, will be close and closer to car, while car is going in road. The

situation of bridge will be changed in monitoring display. As an example same as Figure 3-g

and Figure 3-h. it may have some combinational situation. As in Figure3-i, two changes in

road, bridge and right-turn are reported by tags. In this case, two fields of codes are active.

Figure 6.1: Pictures on monitoring displayer based on appearance of change in road.

a) Nothing in front b) 3-way in front c) turn left in front d) 4-way in front e) turn right infront f) tunnel in front g) bridge in front h) bridge in front i) bridge& turn right in

front


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6.2 DISTANCES FROM ROAD MARGIN

The distance from right margin of the road is an important data, because it can be

used to avoid car deviation. It could be extracted from tags but for this function to be done

true, it is needed the tags to be tight together. We do this by two methods: the first is based

on time and the second one is based on incoming signal power. In both cases, if the distance

of tags is far, it causes this measurement or sense to be non-valuable. Therefore the suitable

case is tightly tags.

A. Power Based

If tags are installed on x meters from the road center, we can detect the power level of

incoming signal from tags and have a criteria of distance of car from tag (or road margin).

The incoming power curve from tags and the reader distance from tag are shown in Figure

6.2a.

Based on this distance, we can activate proper alarms like as green-light in 4, red

light in 3, blink in 2 and buzzer in 1 meter.

Figure 6.2a: Power/distance chart of received power from tag to reader

B. Time Based

We can compute the accurate distance between car and tag or road margin. If we want

to have this information, we must use two tag readers in car, one in front and other in the


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road monitoring cannot be used by user. To overcome this problem, another field is added to

stored data for showing the direct of tags.

This field is numbered in ascending, 1 in the start of road, with increment by one for

next tag. So Figure 6b will be changed to Figure 6.3 form. Order of Tag-no would be

checked by server and if matched by previous ascending order, will be accept, else will be

discarded.

Figure 6.3: Content of tags when there is a tunnel in road and with tag-no.

B. Snow and Rain Effect

Snow and rain reduce the read distance of tags. Snow can effect intensively on

reducing this distance, if it is accumulated on tag. To overcome this problem, we can use tags

with high distance readability. Tags used in the experiment have 7 meter read distance

(XCTF-8102A), but we have to use tags with more read distance. For snow accumulation

problem, we must mount tag on a shady place.


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7.RFID Vs GPSRFID

As you might imagine, thistechnology is best suited for smaller spaces, where theinfrastructure is already in place to use it. RFID requires specialized scanners to read and

transmit data, and without one specific to the proprietary receivers, there's no point. The

dedicated infrastructure may be of great cost on a large scale, but on a small, localized scale,

may be incredibly powerful for both tracking and for providing information.

That being said, they work brilliantly for hundreds of purposes in your everyday

lives, from automatically scanning highway toll fees to using Zip cars to use of public

transportation to preventing shop lifting to IDing livestock to even identifying humans bypassportor implant. RFIDs serve for an incredible variety of purposes, and the number is

just likely to grow.

GPS

Now, GPS is a very different beast from RFID. While it also uses radio waves to

transmit data, it does so using, well, the global positioning system of 24 satellites, as opposed

to specialized scanners here on the ground. Radio waves sent out from this system of

satellites transmit their time and orbital data to receivers down on Earth. Using the data from

multiple satellites, receivers can then triangulate their position relative to the satellites, and

thus on the Earth's surface.

GPS, thus, is best suited for tracking anywhere in the worldbut because of the sheer

distance of the satellites, the signal is weaker, and is easier to jam, or even just not get a

signal. Civilian models particularly are not as accurate in certain situations as one might like,

for instance at the bottom of a canyon or indoors.

Emergency homing beacons, car trackers or navigational devices tend to be the most

well known civilian uses, which don't require accuracy within a few inches, but happen on a

large scale where no other infrastructure such as RFID or radio towers are set up. GPS is, by

definition, global, and so the sort of tracking its best at happens on the scales of tens or

hundreds of miles.
http://www.brighthub.com/electronics/gps/articles/60599.aspxhttp://www.brighthub.com/electronics/gps/articles/60599.aspx


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8.MERITS AND DEMERITSMerits

1. Efficiency: RFID tags do not require line-of-sight to be deciphered they can be readthrough cardboard, plastic, wood and even the human body. RFID tags can easily

track moving objects and send the required information back to the reader. This

eliminates human errors, reduces labor and provides quick access to a wealth of

information.

2. Return on Investment (ROI): RFID costs more to implement than a barcodesystem, but provides a good return on investment in the long run, since RFID issignificantly more efficient.

3. Less Vulnerable to Damage: RFID tags are less susceptible to damage. An RFID tagis securely placed within an object or embedded in plastic, enabling the system to be

used in a variety of harsh environments, such as areas of high temperature or

moisture, or with exposure to chemicals or the outdoors.

Demerits

1. Expense: RFID systems are typically more expensive than alternatives such asbarcode systems. While passive tag reading is similar to (and generally less

expensive than) barcode reading, active tags are costly due to their complexity.

Active tags consist of an antenna, radio transceiver and microchip, increasing the

overall cost of an RFID system.

2. Collision: Tag collision and reader collision are common problems with RFID. Tagcollision occurs when numerous tags are present in a confined area. The RFID tag

reader energizes multiple tags simultaneously, all of which reflect their signals back

to the reader. This result in tag collision, and the RFID reader fails to differentiate

between incoming data. RFID reader collision results when the coverage area


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managed by one RFID reader overlaps with the coverage area of another reader. This

causes signal interference and multiple reads of the same tag.

3. Security: RFID technology gives rise to numerous security concerns. Since thesystem is not limited to line-of-sight, external (and malicious) high-intensitydirectional antennas could be used to scan sensitive tags. Fraud is always a

possibility when the technology is used for high-security operations, such as payment

verification.


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9.FUTURE SCOPE AND CONCLUSIONA number of RFID tags are implanted in road. These tools are not expensive for

public facilities. The suggested method is well suited to foggy road and poor visibility

environment. While cars pass through road, tag messages could be cared and be monitored.

In most of the vehicular applications, the RFID tag is mounted on the vehicle and the

reader on the roadside unit, but in our design, this is inverse. In this project RFID tags are

placed on the road at fix interval and directions. In developed technique of using these tags,

we can use a dual RFID reader resulting to detect the distance of cars from road-margin. Also

by posting the tags in the road center and putting two sides data in tags, reader can extract its

own data form tags.

For future work: first: since a, b, c, d, e and f numbers are 7-bits binary numbers, it ispossible to improve the monitoring system to 127 meters of in front road, instead of 100

meters. Second: by incrementing the accuracy of distance computing, we can use them for a

driver-less car in an intelligent car.


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REFERENCES

[1] Al-Khateeb, K.A.S., Johari, J.A.Y. and Al-Khateeb, W.F., 2008. Dynamic Traffic Light

Sequence Algorithm Using RFID, Journal of Computer Science 4 (7), pp. 517 -524., DOI:

01.3844/jcssp.517.524

[2] Cook, Robert, 2006. An RFID Information e-Highway, Computer science colloquium,

Hong Kong, 19-22 June 2006, Department of Computer Science City University.

[3] Garza, J.M., and Fedrowitz, W., 2008. "Implementation of RFID Technology in the VT-

VDOT Highway Maintenance Monitoring Program (HMMP)," Proceedings of the Intelligent

Computing in Engineering Conference, Plymouth, United Kingdom, July 2008, pp. 518-527

[4] Hwang, K., Kim, K. and Eom, D., 2006. DiCa: Distributed Tag Access with Collision

avoidance Among Mobile RFID Readers, IFIP International Federation for Information

Processing 2006, pp. 413422.

[5] Lee, Eun-Kyu, Yoo, Young Min, Park and Chan Gook, 2009. Installation and

Evaluation of RFID Readers on Moving Vehicles, VANET09, September 25, 2009, Beijing,China, 2009

[6] Ok, Min-hwan,2009 A Location Tracking by RFID to Assist the Transportation

Vulnerable in Subway Stations, Mathematical Methods and Applied Computing, WSEAS

Press, pp. 704-706. www.wseas.us

[7] Yoo, J., Kim, B., Jung, Ho., Park, C. and Ko, Y., 2008. INTRACS: Intelligent Traffic

control System Based on Ubiquitous Technology, INFOS2008, March 27-29, 2008 Cairo-

Egypt, pp. 78-83

[8] Zebra_tech, 2011. An Introduction to Passive RFID, RFID Journal, white paper,

January 2011 pages12 www rfidjournal com

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