WIRELESS SCREEN SYSTEMS AND PROTOCOLS

SYSTEMES ET PROTOCOLES DE FILTRAGE SANS FIL

English Abstract

Screening systems and protocols are disclosed that are used to screen and
identify objects
with RFID tags. The screening categorization, RF transmitting-receiving
methods and
communication protocols are dynamically programmable. An object screening
system
includes one control centre, one or more broadcast means, one or more tags and
one or
more detectors. The control centre stores registered tag data including tag
IDs and
attached object properties, categorizes all tags based on detection requests,
and
broadcasts commands to tags and detectors, through the broadcast means, in
order to set
tags' status and operating mode, and synchronize detectors' settings. A tag
reports its
status to a detector in its vicinity, and the detector selectively sets up a
two-way
communication with the tag and outputs detected results from the tag.
Communication
protocols are disclosed that cipher and decipher RF signal massages from a
control centre
to tags and detectors, from a tag to a detector, and communications between a
tag and a
detectors, so as to make the object screening system confidential, robust and
reliable.

Claims

What is claimed is:
1. A system for screening vehicles within a geographical area, the system
comprising:
a). one control centre, for storing vehicles' registration, responding
requests from
either vehicles' owners or designated government officers, and broadcasting
control-centre commands;
b). one or more broadcast means, for broadcasting the control-centre commands
from
the control centre over the geographical area in RF frequencies;
c). one or more tags, attached to vehicles, each of the tags comprising: data
memory
for storing tag data including tag identification number serving as
communication
address and tag status history; one RF communication means having three
communication channels for respectively receiving the control-centre commands
from the control centre through the broadcast means, emitting tag message in
random time intervals, and responding requests in two-way communication in
slave
mode; a clock for stamping received commands with time; and a timer for
resetting
the tag itself back to a default operation mode in a period of time specified
in
received commands;
d). one or more detectors, either carried by men or mounted on vehicles or
stationary
platforms, each of the detectors comprising: data memory for storing detector
data
including detector identification number serving as communication address and
authorization data; one RF communication means having three communication
channels for respectively receiving the control-centre commands from the
control
centre through the broadcast means, monitoring the tag message emitted from
tags
in its vicinity, and setting up a two-way communication in master mode with a
particular tag in a close communication range and retrieving the tag data from
the
tag; an interface for configuring and authorizing the detector, making
commands to
the tag, displaying detecting results and the tag data, and remotely
communicating
with either the control centre or any government offices; and a timer for
disabling
the detector in a specified period of time defined in each authorization;
e). an algorithm, for dynamically encrypting and decrypting the control-centre
commands from the control centre to the tags and the detectors, the tag
message
emitted from the tags and received at the detectors, and the two-way
communication between a tag and a detector.
2. A system, as in claim 1, wherein each of said tags further comprises one RF
communication channel for receiving commands from a second command source;
each of
said detectors further comprises one RF communication channel for transmitting
commands to the tags in its vicinity as the second command source; and said
algorithm is
further for dynamically encrypting and decrypting the information in the
second
command source.
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3. A system, as in claim 1, wherein each of said tags further comprises a
plurality of
RF communication channels for emitting the tag message in a combination
pattern
designated in the commands from either the control centre or the second
command
source; and each of said detectors further comprises a plurality of RF
communication
channels for monitoring the tag message emitted from the plurality of RF
communication channels of the tags in its vicinity.
4. A system, as in claim 1, wherein said tag identification number, used as
tag
communication address, comprises a plurality of information fields for
including and
grouping information of vehicle's serial number, plate number, colour code and
model
number, the ownership data such as owner's postal code and country code, and
other
meaningful characters for identification.
5. A system, as in claim 1, wherein said detector identification number, used
as
detector communication address, comprises a plurality of information fields
for including
and grouping information of detector's serial number and model number, the
ownership
data such as owner's postal code and division code, and other meaningful
characters for
classification.
6. A system, as in claim 1, wherein said control-centre command comprises
screening
code, indicia of duration time, and indicia of operation mode including
indicia of the
encrypting and decrypting methods of said algorithm.
7. A system, as in claim 1, wherein said control-centre commands are inserted
in
communication data frames with a destination address, derived from the tag
identification
numbers and the detector identification numbers, for targeting either all of
the tags, all of
the detectors, a specific group of the tags, a specific group of the
detectors, an individual
tag or an individual detector.
8. A system, as in claim 6 and 7, wherein the particular tag, targeted by the
destination address with the control-centre commands from the control centre,
sets its
operating mode including the encrypting and decrypting methods, updates the
tag
message with the screening code in the commands, and emits the tag message in
random
time intervals continuously for the duration time defined in the commands.
9. A system, as in claim 2, wherein the command from said second command
source
comprises screening code, indicia of duration time, and indicia of operation
mode
including indicia of the encrypting and decrypting methods of said algorithm.
10. A system, as in claim 2, wherein the command from said second command
source
are inserted in communication data frames with a destination address, derived
from the
tag identification numbers, for targeting either all of the tags, a specific
group of the tags,
or an individual tag.
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11. A system, as in claim 9 and 10, wherein the particular tag, targeted by
the
destination address with the commands from the second command source, sets its
operating mode including the encrypting and decrypting methods, updates the
tag
message with the screening code in the commands, and emits the tag message in
random
time intervals continuously for the duration time defined in the commands.
12. A system, as in claim 1, wherein said tag message comprises indicia of
communication address being ready for the two-way communication with a
detector.
13. A system, as in claim 1, wherein the random time intervals are in a range
that the
longest interval should be short enough for the tag to emit its tag message at
least twice to
a detector during the tag and the detector's approaching to each other.
14. A system, as in claim 1, wherein said tags further comprises an interface
for
instructing vehicle's operator.
15. A system, as in claim 1, wherein each of said tags further comprises a GPS
receiver for determining its location.
16. A system, as in claim 1, wherein each of said detectors further comprises
a GPS
receiver for determining its location.
17. A system, as in claim 1, wherein each of said tags further comprises
inertial
sensing accessories for determining vehicle's moving trajectory and trouble
conditions.
18. A system, as in claim 1, wherein the tags in said default operation mode
emit
dummy tag message comprising a dummy screening code and indicia of
communication
address ready for the two-way communication with a detector.
19. A system, as in claim 18, wherein said control centre broadcasts the dummy
screening code to all tags and all detectors. The value of the dummy code
changes with
time to synchronize all detectors dynamically.
20. A system, as in claim 1, wherein said tags comprise backup power
accessories.
21. A system, as in claim 1, wherein said detectors are administrated in a
plurality of
ranks in a tree structure that a detector in a higher rank can authorize and
revitalize any
detectors in the lower ranks within its branch.
22. A system, as in claim 6 and 7, wherein the particular detector, targeted
by the
destination address with the control-centre commands from the control centre,
sets its
operating mode including the encrypting and decrypting methods.

Description

CA 02469377 2004-05-31
WIRELESS SCREEN SYSTEMS AND PROTOCOLS
TECHNICAL FIELD
This invention relates to method for screening movable objects with RFID tags,
such as
vehicles.
BACKGROUND
Screening systems for enhancing safety are widely used at important
facilities, such as
airports, to detect any dangerous or illegal materials in luggage or with
passengers.
Micro electronic identification chips are also known to be so small that they
can be
embedded in human bodies. With explorations on GPS technologies, many methods
have been developed to track objects, such as animals, vehicles, materials,
and so on.
The vehicle tracking techniques make the tracked vehicles safer. However, the
dangerous threats to a community are often from untracked vehicles. There are
a number
of problems in the vehicle tracking techniques for enhancing community safety.
The first
problem is that it is impossible to track all vehicles due to bottlenecks in
computer
speeds, data storage capacities and communication network abilities. The
second
problem is that data collected from tracking process is huge and most of the
data is
useless.

CA 02469377 2004-05-31
The micro electronic identification chip idea is not quite suitable for
identify individual
human being. It is because that a chip embedded in human body may hurt
surrounding
body tissues, cause the carrier's safety, and damage the carrier's privacy and
confidence.
There is a need for simple, high-speed and accurate object screening systems
to screen
and identify any movable objects, such as vehicles, at interested passes, so
as to reduce
threats to community safeties.
SUMMARY OF INVENTION
The invention provides an object screening system and protocols which have
advantages
in enhancing community safety significantly to a certain level in a large
area. The first
aspect of the invention provides a system for screening vehicles within a
community.
The system comprises one control centre, one or more broadcast means, one or
more tags
embedded inside local vehicles and one or more detectors. A tag is a RFID
device, either
built in a new vehicle or installed into a vehicle, under certain regulations.
The tag in a
vehicle has to be registered in the control centre during installing or first-
time selling.
The identification number of the tag is unique within the community and may
serves as
tag address. When transferring ownership of a vehicle with a tag, it is
mandatory for its
older owner, new owner or both to make sure to update the changes to the
control centre.
The control centre stores registered tag data including tag IDs, vehicle's
serial numbers
and plate numbers and their ownerships, categorizes all tags based on
screening or
detecting requests, and broadcasts commands to tags and detectors through the
broadcast
means in order to set tags' status and operating mode and to synchronize
detectors'
settings. The broadcast means can be any kind of RF broadcasts. A tag responds
to
commands from the control centre via the broadcast means and reports its
status to a
detector in its vicinity, and the detector selectively sets up a two-way
communication
with the tag and outputs detected results from the tag through an input/output
interface.
The tag has an optional GPS receiver and optional inertial sensing accessories
to record
its movement and detect object collision and other trouble conditions. The
detector has
optional broadcast accessories to issue commands to all tags in its vicinity.
Another aspect of the invention provides a system for screening vehicles
worldwide. The
system comprises one control centre, one or more broadcast means, one or more
tags
embedded in vehicles and one or more detectors. A tag is a RFID device, either
built in a
new vehicle or installed into a vehicle, under regulations of a nation,
nations or United
Nations. The tag in a vehicle has to be registered in the control centre
during installing or
first-time selling. The identification number of the tag is unique worldwide
and may
serves as tag address. When transferring ownership of a vehicle with a tag, it
is
mandatory for its older owner, new owner or both to make sure to update the
changes to
the control centre. The control centre stores registered tag data including
tag IDs,
vehicle's serial numbers and plate numbers and their ownerships, categorizes
all tags
based on screening or detecting requests, and broadcasts commands to tags and
detectors
through the broadcast means in order to set tags' status and operating mode
and to
synchronize detectors' settings. The broadcast means can be any kind of RF
broadcasts,
such as satellite broadcast for GPS. A tag responds to commands from the
control centre
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CA 02469377 2004-05-31
via the broadcast means and reports its status to a detector in its vicinity,
and the detector
selectively sets up a two-way communication with the tag and outputs detected
results
from the tag through an input/output interface. The tag has an optional GPS
receiver and
optional inertial sensing accessories to record its movement and detect object
collision
and other trouble conditions. The detector has optional broadcast accessories
to issue
commands to all tags in its vicinity.
Communication protocols provided in the invention are used to cipher and
decipher RF
signals, such as that from a control centre to tags and detectors, that from a
detector to
tags, that from a tag to a detector, and a two-way communication between a tag
and a
detector, in an object screening system provided in the invention. The
screening
categories, RF transmitting-receiving methods and communication protocols are
dynamically programmable, so as to make the object screening system
confidential,
robust and reliable.
Typical applications of object screening systems and protocols provided in the
invention
include 1) searching for stolen vehicles; 2) blocking un-registered vehicles
for a special
event; 3) controlling traffic; and 4) rescuing troubled vehicles.
BRIEF DESCRIPTION OF THE DRAWING
In drawing which illustrates specific embodiment of the invention, but which
shoult not
be construed as restricting the spirit or scope of the invention in any way:
FIG. 1 is a diagram of an object screening system and protocols
DESCRIPTION
The invention provides object screening systems and protocols that are used to
screen
movable objects and identify the interested ones for the purpose of enhancing
community
safety. The invention is described with four typical applications in
following.
Before starting description of any applications, assume an object screening
system for
vehicles is well established in an area for each of these typical
applications, as shown in
FIG.1. The object screening system comprises one control centre 110, one or
more
broadcast means 120 that are connected with the control centre 110 and able to
broadcast
RF signals 121 with commands from the control centre 110, one or more tags
130a,
130b, 130c, 130d and 130n that are available on some vehicles, and one or more
detectors 140. The tags are registered in the control centre 110 and able to
receive the RF
signals 121 from the broadcast means 120, to transmit a RF signal 131 based on
the
commands from the control centre 110. The commands from the control centre 110
are
able to target either all of tags, specific groups of tags, or an individual
tag. A detector
140 is able to receive the RF signals 121 from the broadcast means 120, to
receive the RF
signal 131 from the tag 130a, to set up a two-way RF communication 141 with
the
interested tag 130a, to broadcast RF signals 142 to the tags 130a and 130b in
its vicinity,
and to output screening results through an input/output interface.

CA 02469377 2004-05-31
The first typical application of an object screening system is to search
stolen vehicles.
When a vehicle has been stolen, its owner is responsible to report the loss to
the control
centre immediately. The control centre will categorize the tag of the vehicle
with a status
marked as "stolen". Then, the control centre broadcasts commands, including
tag's ID
and instructions for the tag, out to reach all tags in the area. The tag in
the stolen vehicle
receives the commands from control centre, changes the status and operating
mode based
on the instructions and emits RF signal marked as "stolen". A detector will
pick up the
signal from the stolen vehicle when the stolen vehicle passes by and indicates
the vehicle
as a stolen one. The tag may has a backup power supply and should not be
disabled or
destroyed easily. There is always a chance that the tag has been disabled. So,
any
vehicles will be suspected as stolen ones if they do not emit right RF
signals. It will not
be a problem if tags are mandatory for all vehicles for certain kinds.
The second typical application of an object screening system is to block un-
registered
vehicles for a special event. When a special event is held at a place, the
safety could be
improved significantly if only the registered vehicles are allowed to the
place and the
surrounding area. For example, thousands of registered attendants will take
their
thousands of vehicles to a event. The organizers and attendants are
responsible to register
all their vehicles for the event and report to the control centre. The control
centre will
categorize the tag of these registered vehicles with a status marked as "Event
Attendant".
Then the control centre broadcasts commands out to reach all tags in the area
during
certain periods of entering time. The tags in the vehicles registered for the
event receive
the commands from the control centre, change the status and operating mode
based on
the instructions and emit RF signal marked as "Event Attendant". The detectors
will pick
up the signals from vehicles and allow the vehicles emitting the correct RF
signal to pass
at event entrances. Any other vehicles will be blocked or turned away which
emit either
wrong RF signal or nothing. Communication protocols are designed to make the
object
screening system robust and reliable.
The third typical application of an object screening system is to control
traffic. All
vehicles from the same direction often need to be split for sakes of
construction
conditions, community safety, vehicle types and vehicle status. For example,
there are
coming-home vehicles and going-abroad vehicles in the same traffic at a border
between
two countries. These two kinds of vehicles need to pass through two different
kinds of
gates for customs declaration. The tags in all of these vehicles may not need
to be
registered at the control centre. The control centre broadcasts common
commands out to
reach all tags continuously. The tags in these vehicles receive the common
commands
from the control centre and a special command requesting nationality from the
broadcast
accessories of a detector in their vicinity, and emit RF signals marked with
nationality
information. The detector picks ug the signal from a vehicle, outputs a result
with
nationality information of the vehicle and guides the vehicle to a designated
gate.
The fourth typical application of an object screening system is to rescue
troubled
vehicles. The tags in the object screening system have GPS receivers and
inertial sensing
accessories to record vehicle movement and detect vehicle collision and other
trouble
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CA 02469377 2004-05-31
conditions. For example, one vehicle has an accident and its driver and all
passengers if
any may lost consciousness. The tag in the vehicle is able to judge if the
vehicle is in
trouble by detecting the impact, vehicle's gesture and doors' status. There is
a backup
power supply to the tag. The tag emits a RF signal based on the ciphering
rules from the
control centre. A detector in a patrol vehicle picks up the signal from the
tag when both
vehicles come close. The detector sets up a two-way communication link to the
tag,
reads data from the tag including the location information, and outputs the
results through
its input/output interface.
As will be apparent to those skilled in the art in the light of the foregoing
disclosure.
Many alterations and modifications are possible in the practice of this
invention without
departing from the spirit or scope thereof. Accordingly, the scope of the
invention is to
be construed in accordance with the substance defined by the following claims.
(What is claimed will be filed later)
s

Representative Drawing