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Description  |
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TECHNICAL FIELD
This invention relates to automatic payment systems in general, and more
particularly to electronic toll collection for moving vehicles.
BACKGROUND OF THE INVENTION
Unless a willingness exists to embrace mass transportation and, thus,
decrease the use of personal automobiles, traffic delays will be a growing
and unfortunate fact of life. Ultimately, mass transportation systems will
become a more significant part of everyday travel due to population growth
and the costs (personal and environmental) associated with highways packed
with automobiles-each carrying one person. One of the costs comes in the
form of highway congestion and the anguish that accompanies long traffic
delays. However, until more convenient and cost-competitive, mass
transportation systems become available, it is desirable to improve the
highway congestion problem, and nowhere is it worse than around toll
booths.
The use of toll booths on highways is viewed as a mixed blessing by
motorists. Most will agree that safe, high-speed, well-maintained highways
are vital to the quality of their life; that such highways are expensive;
and that toll booths provide an equitable way to pay for them. On the
other hand, most will agree that stopping in order to pick up a ticket
and/or make a payment is an annoyance, particularly during peak traffic
periods when toll payment queues exceed several minutes. The fuel wasted
and pollution created, while waiting in a queue, is significant when large
numbers of automobiles are involved. Considering the many conveniences
available in present day automobiles and the generally high quality of
toll roads, the annoyance displayed by motorists when encountering a
traffic delay is somewhat surprising. Nevertheless, the desire for
increased transit speed appears insatiable.
U.S. Pat. No. 4,338,587 discloses a vehicle toll collection system that
automatically identifies vehicles in an "express" lane. In order to
benefit from the express lane, vehicles are equipped with radio frequency
transmitters that send data to electronic toll collecting apparatus to
identify the vehicle using information such as the state of registration
and license number. Tolls are billed to the vehicle owner's account, and
payment is disbursed by an agency that both issues license plates and
collects toll payments (in advance) from the vehicle owner. Although this
technique is useful, it requires a great deal of administrative overhead
and is susceptible to fraud. For example, the transmission of incorrect
information (the license number of another vehicle) is not detected until
the next time the owner of the other vehicle is billed.
U.S. Pat. No. 4,963,723 discloses an automatic toll collector for toll
roads which requires the driver of a vehicle to insert an integrated
circuit (IC) card into each toll booth. The IC card stores both license
and bank account information. Tolls are withdrawn from the card holder's
bank account, and means are provided for comparing the license information
with the actual license plate which is acquired as the vehicle passes
through the toll booth. However, this system offers little or no
improvement in the speed of toll collection since the driver is required
to stop. But even if the information on the IC card were electronically
transmitted to the toll booth, the improved security against fraud comes
at great inconvenience to both the card holder and the highway authority.
Card holders should be able to pay the toll for any vehicle that they
happen to be in (a friend's car, a rental car, etc.), not just specific
vehicles; and additional equipment is needed to read each license plate.
The latter is not only a significant technical challenge but also requires
cooperation among various states regarding license design if out-of-state
drivers are to benefit from such a system.
One popular technique for making high speed toll payments is through the
use of a miniature transponder that attaches to the windshield of a
vehicle and broadcasts an identification signal when it enters an
electromagnetic field having predetermined characteristics. Because such
transponders operate at radio frequencies, they have become known as
RF-tags. Unfortunately, electronic eavesdropping is relatively easy in
such a system; the transmitted identification signal can be intercepted,
recorded, and rebroadcast by another vehicle to avoid toll payments. It
appears to be a fact of life that when theft is too easy to accomplish,
even the most honest people indulge; and when theft requires great effort,
even scoundrels behave.
In systems where payments are made by the transfer of data, care must be
taken to assure that the data represents an accurate indication of the
purported information. Tampering with the device containing the data can
produce various undesirable results that comprise the integrity of the
data and thereby defeat the payment scheme. For example, if the account
number on a credit card is altered, then the transaction is charged to the
wrong person; and if the cash balance on a debit card is increased in an
unauthorized manner, then the creditor is defrauded. It is therefore
desirable to provide a secure toll collection scheme for moving vehicles.
SUMMARY OF THE INVENTION
In accordance with the invention, secure toll payment is accomplished by
transmitting a changeable verification number to a moving vehicle.
Thereafter, the moving vehicle uses the verification number to encrypt the
verification number according to a predetermined algorithm and then
broadcasts the resulting signal. Because the verification number changes
from time to time, so too does the nature of the signal which is broadcast
by the vehicle; and fraud, based on electronic eavesdropping, is
substantially eliminated.
In an illustrative embodiment of the invention, the verification number
comprises an 8-bit number and a time/data number. A smart card is inserted
into a vehicle-mounted transponder unit, but is easily removed and carried
by the vehicle owner. Being no larger than a conventional credit card, the
smart card can be carried in the owner's wallet. Approximately one-half
second is allocated to the smart card and transponder unit for processing,
and a pair of spaced-apart antennas are sequentially positioned in an
express payment lane at a toll plaza to accommodate vehicles moving at
high speed.
In the illustrative embodiment, a debit card is locked during the debit
process, and unlocked when it is successfully completed. This prevents
fraud by those who would remove the card from the transponder during the
debit process in order to avoid making payment.
Security is further improved by use of the Data Encryption Standard (DES)
algorithm, stored in the smart card's memory, to encrypt the encryption
code into ciphertext. DES has the advantage that it is well known and
documented. It is a private key system that is highly secure as long as
the private key is kept secret. DES has the further advantage that its
ciphertext output is reversible--i.e., ciphertext C can be decrypted back
into the original message M using the same private key.
BRIEF DESCRIPTION OF THE DRAWING
The invention and its mode of operation will be more clearly understood
from the following detailed description when read with the appended
drawing in which:
FIG. 1 is a bird's eye view of a highway toll plaza that includes an
express lane for toll collection using a two-antenna system in accordance
with the invention;
FIG. 2 illustrates a futuristic high speed toll collection system in
accordance with the invention;
FIG. 3 discloses a block diagram of the equipment located at a toll plaza
for collecting payments in accordance with the invention;
FIG. 4 shows a transponder mounted on the interior windshield of a vehicle
and a motorist inserting/removing the smart card;
FIG. 5 shows a transponder with a smart card inserted therein such as used
in the present invention;
FIG. 6 discloses a block diagram of the transponder used in the present
invention;
FIG. 7 is a block diagram of the major functional components of a smart
card interconnected to a reader/writer unit and their general
interconnection with each other;
FIG. 8 is a flow diagram that illustrates the various steps performed in
practicing the invention;
FIG. 9 discloses the format of a 128-bit transponder data frame comprising
fixed and variable data frames;
FIG. 10 discloses the format of the fixed data frame portion of the
transponder data frame;
FIG. 11 discloses the format of the variable data frame portion of the
transponder data frame, transmitted by the vehicle to antenna 1 of the
Roadside Reader (RSR), immediately after an activation signal is received.
FIG. 12 discloses the format of the variable data frame portion of the
transponder data frame transmitted by the RSR to the vehicle from antenna
1, this information is also referred to as the encryption code;
FIG. 13 discloses the format of the variable data frame portion of the
transponder data frame transmitted by the vehicle to antenna 2 of the RSR;
and
FIG. 14 discloses the format of the variable data frame portion of the
transponder data frame transmitted by the RSR to the vehicle from antenna
2, this information is also referred to as the encrypted acceptance
message.
DETAILED DESCRIPTION
Briefly, the present invention resides in a system that allows vehicles to
pass through specially designed toll booths at relatively high speeds-at
least as high as safety considerations allow. As motorists approach the
toll booth, they insert a smart card into a transponder unit which reads
identification information stored on the card and transmits it, via radio
frequency, to a roadside reader (RSR) which comprises a pair of
spaced-apart antennas and a computer (Plaza Server) which serves the toll
booth in matters of electronic toll payment. In response, the RSR either
debits the card or charges the toll to the motorist's account. The details
of this transaction are then transmitted from the roadside controller back
to the transponder, and a record is written into the smart card. This
system is implemented in such a way that it operates with fixed or
variable payment toll booths. Further, techniques are disclosed that
prevent fraud while providing maximum convenience to both the motorist and
the highway authority. These benefits will become apparent as the details
of implementation are revealed.
FIG. 1 discloses a bird's eye view of a toll payment area which uses the
toll collection system of the present invention. The toll payment area
comprises an enlarged portion of highway and a number of toll collection
booths 41-45. Such toll booths may be located at the entrance of a limited
access highway, bridge or tunnel where fixed amounts of money are
collected for the privilege of using that particular facility, or where
tickets are given to each vehicle that indicate the location where it
entered the highway. Such toll booths may also be located at the exit of a
limited access highway where they are used for the collection of variable
tolls. There, tickets are collected (to avoid possible fraudulent use
later) and payment is determined by the particular entrance where the
vehicle entered the highway. The present invention is suitable for use in
all of these situations.
The enlarged portion of highway includes lane 30 which is used by motorists
who wish to use cash or tokens in making toll payments. Unfortunately,
making such payments requires that vehicles come to a complete stop, and
frequently they must wait until others have completed their payment before
beginning their own transaction at one of the toll booths 42-45. The
enlarged portion of highway also includes express lane 20 which is used by
motorists who are equipped to make electronic payment without stopping.
Prior to entering lane 20, however, the motorist inserts a payment card
into a transponder unit that mounts on the windshield (see FIG. 4) or
dashboard of vehicle 50. Information from the card is loaded into the
transponder which awaits an activation signal from antenna 1. The
activation signal is triggered when a vehicle drives over a loop sensor 25
which, illustratively, is embedded in the roadway just prior to reaching
antenna 1. Alternatively, antenna 1 continuously broadcasts an activation
signal. In either scenario, the activation signal triggers an information
exchange between the transponder and antenna 1. Further along lane 20,
antenna 2 is positioned to exchange additional information with the
transponder unit in vehicle 50. These antennas are spaced apart to provide
a time interval (approximately 500 milliseconds) which is used for
processing the information received from antenna 1 before exchanging
additional information with antenna 2. The results of these exchanges are
displayed on message display 3 (illustratively, an overhead sign) under
control of a Lane Controller which tells the motorist either to continue
ahead in lane 21, or to pull over into lane 22 where toll booth 41 is
located. Motorists would be asked to pull over, for example, when there
are insufficient funds within the card (when debit cards are used), when
the card has been reported as being lost or stolen, when data transmission
errors are detected, etc. At toll booth 41, motorists can purchase debit
cards, make cash payment (usually because they have inadvertently entered
express lane 20), or increase the money balance on their existing debit
card. A video camera 4 is positioned to photograph the license plates of
vehicles that do not make the proper payment, possess a lost/stolen debit
card, or are driving a vehicle that does not correspond to the vehicle
class information stored in the debit card.
FIG. 2 illustrates a futuristic view of a multi-lane system for the rapid
payment of tolls. It is noted that a single structure 10 combines the
functions of antennas 1, 2 and display 3 shown in FIG. 1. The multiple
data exchanges between the transponder in the vehicle and structure 10 can
occur at data processing speeds which permit the use of a single
antenna--such as shown. The cost associated with higher data processing
speeds suggests that it is more cost effective, at the present time, to
use a pair of spaced-apart antennas. Nevertheless, the present invention
is adaptable to a single antenna system.
EQUIPMENT
Elements of the preferred embodiment are shown in FIG. 3 which illustrates
the various items used for providing rapid toll collection in a multi-lane
system. Plaza Server 310 is, illustratively, an AT&T/NCR (3400 Class)
computer which communicates with a Toll Authority host computer, via
telephone lines (9.6-56 Kb/s), and with the equipment that monitors and
serves a number of high speed payment lanes. Roadside Reader (RSR) 320 and
Lane Controller (LC) 330 each handle up to four lanes under control of the
Plaza Server 310. Although additional RSRs and LCs may be connected to the
Server, only one of each is shown for the sake of clarifying the
invention. Similarly, only the apparatus needed to handle a single high
speed lane is shown. Loop 25 senses an oncoming vehicle in a particular
high speed payment lane and delivers this information to Server 310 via LC
330. Antenna 1 then transmits an activation signal to the oncoming vehicle
under control of RSR 320. In the illustrative embodiment, RSR 320
comprises the equipment needed for modulating/demodulating signals in the
radio frequency (RF) range from 902 to 928 MHz in order to adapt data
signals for transmission through the air. A pair of antennas serve each
lane. After the vehicle passes these antennas, the results of the data
exchange between the vehicle transponder and the antennas are visually
communicated to the motorist in the vehicle by means of message display 3
which is driven by LC 330 under control of Server 310 which provides one
of a plurality of different messages. Plaza Server 310 also controls a
video camera 4 which is generally used to record the identity of vehicles
that do not make proper payment.
FIG. 5 illustrates the appearance of the transponder 600--a vehicle-mounted
unit which communicates with antennas 1 and 2 to make toll payments and
transfer data to/from smart card 500 which is inserted therein.
Transponder 600 attaches to the dashboard or windshield (see FIG. 4) of
the vehicle via mounting apparatus 610 which rotates to accommodate
various mounting positions. The front front surface of the transponder
includes a slot for receiving the smart card, and lights 621, 622, 623 for
providing visual indications to the motorist. A block diagram of the
interior of transponder 600 is shown in FIG. 6. When a smart card is
inserted into reader/writer unit 700, a switch is operated which causes
power to be applied to the transponder. The transponder may be battery
powered although the temperature range that the battery must endure is
formidable. In the preferred embodiment of the invention, primary power is
supplied to the transponder through plug 601 which connects to the vehicle
battery (12 volts) via a cigarette lighter receptacle. Power conditioner
640 converts the 12 volt input power into output power at 5.0, 6.5 and 8.0
volts. Microcontroller 650 (illustratively an Intel 87C51FC 8-bit
microprocessor) includes memory (ROM and RAM) which stores operating
instructions for controlling the operation of the transponder.
Microcontroller 650 controls visual indicator 620 which comprises LEDs
621, 622, 623 (see FIG. 5), and audible indicator 630 which comprises a
piezoelectric transducer plus associated oscillators and timers.
Microcontroller 650 transmits digital data to RF modulator 670 which has a
nominal carrier frequency of 915 MHz. The modulated RF signal is amplified
by amplifier 665 and delivered to transmitting antenna 680. Antenna 690
receives RF signals from the equipment shown in FIG. 3. These RF signals
are amplified by amplifier 675, demodulated by RF demodulator 670 and the
resulting data is delivered to microcontroller 650. Certain data is
intended for the smart card, either for processing or for storage in the
smart card's memory; and this data is delivered to reader/writer unit 700
over serial data bus 710.
Smart Card
Referring now to FIG. 7 there is disclosed a block diagram of a smart card
500 and a reader/writer unit 700 such as used in connection with the
present invention. Although disclosed in greater detail in U.S. Pat. Nos.
4,797,898 and 4,798,322, a brief description is presented here. Some of
the principal components located on smart card 500 are microprocessor 560,
electrically erasable programmable read-only memory (EEPROM) 550, analog
interface circuit 540, secondary winding 521 of transformer 920, and
capacitive plates 541-544.
Microprocessor 560 includes a central processing unit and memory means in
the form of random access memory and read-only memory. A microprocessor
available from Intel Corporation such as Part No. 80C51 may be used with
the proper programming. Operating under filmware control provided by its
internal read-only memory, the microprocessor 560 formats data to the
EEPROM 550 and to the reader/writer unit 700 via the analog interface
circuit 540. EEPROMS are available from a number of suppliers. Data may be
written to or used from an EEPROM repeatedly while operating power is
being applied. When operating power is removed, any changes made to the
data in the EEPROM remain and are retrievable whenever the smart card 500
is again powered.
The analog interface circuit 540 provides a means for interfacing smart
card 500 with reader/writer unit 900. Within analog interface 540 are
circuits responsive to capacitors 541-544, for exchanging data with
reader/writer unit 900. Power for operating the card 500 is provided to
the analog interface circuit 540 via inductive transfer, received by the
secondary winding 521 of transformer 720. This transformer is formed when
secondary winding 521 is coupled to a primary winding 721 within the
reader/writer unit 700. The transformer 720 may advantageously include a
ferrite core 722 in the reader/writer for increased coupling between the
transformer primary winding 721 and secondary winding 521. A second such
core 522 may also be included within the smart card portion of transformer
720 to further increase coupling efficiency. The primary winding 721 is
driven at a 1.8432 MHz rate by power supply 930 whose operation is
described with particularity in U.S. Pat. No. 4,802,080 issued Jan. 31,
1989.
Within the reader/writer unit 700, analog interface circuit 740 exchanges
data with the smart card 500 under control of microprocessor 760.
Capacitor plates 741-744 are aligned with the mating capacitor plates
541-544 within the smart card 500. The input/output serial data interface
750 is basically a universal asynchronous receiver transmitter (UART)
which may be advantageously included in the microprocessor 760.
PROCESSING
Preload
Users protect their smart card as they protect their credit card, typically
by carrying it in their wallet. Advantageously, once the card is removed
from the transponder, the transponder is no longer operative for the
payment of tolls. However, the smart card itself continues to be useful
for the payment of other goods and services. Indeed, there is considerable
marketing appeal for a card, issued by a regional transportation
authority, that can be used for the payment of related highway services
such as roadside telephones, restaurants, gasoline, and even speeding
tickets.
As illustrated in FIG. 4, a motorist inserts smart card 500 into the
transponder 600 sometime before having to make an electronic toll payment.
Typically this occurs when he enters the vehicle if a toll booth is
expected. Upon insertion of the card, the tr | | |
