Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02447401 2003-10-31
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VEHICLE AND/OR ASSET TRACKING AND LOCAL(ZATlON SYSTEM AND
METHOD
FIELD OF THE INVENTION
The present invention relates to a vehicle andlor asset tracking and
localization
system and method for determining absolute vehicle/asset location.
f
BACKGROUND OF THE INVENTION
Various systems have been suggested to date to enable the locating and
tracking
of stolen or missing vehicles. For example, US patent No. 5,895,436 (SAVOIE)
discloses a vehicle tracking system using the existing cellular network,
whereas
US patent No. 5,225,842 (BROWN) discloses a vehicle tracking system
employing global positioning system (GPS) satellites for positionllocation
determination.
However, such prior art tracking systems are very dependent upon third party
infrastructures to determine location information, which is disadvantageous
for
many reasons.
For example, tracking systems that use the cellular network are limited by
constraints such as having to locate the missing vehicle through relative
signal
strength methods between cellular base stations. These systems also require
several back and forth signalling transmissions between the location
transceiver
mounted in the vehicle and the base stations of the cellular network. One
disadvantage of such tracking systems is that the cell distribution is not the
same
throughout the network and the accuracy of the tracking may vary depending on
the number of base stations available at any site.
In the case of GPS tracking systems, the signals that are used are even weaker
than in cellular networks requiring antennas with a clear view to the sky,
also GPS
does not work indoors.
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There is therefore a need for a vehicle andlor asset tracking tracking system
that
is not dependent on the infrastructure of the existing wireless systems to
obtain
the location information of a missing vehicle or asset.
Furthermore, in this same field of vehicle security, it is known to use
wireless
remote cut-off modules to disable critical components in a vehicle such as
fuel
pumps, ignition, starter, fuel injection, etc., to prevent engine starting by
unauthorized users.
The main disadvantage of present cut-off modules is the fact that since they
must
be wired to the main control unit, the wiring is easy to follow. Therefore
they can
be located and bypassed with little effort.
SUMMARY OF THE INVENTION
According to the present invention, there is provided a tracking system for
locating
a vehicle andlor asset comprising:
an inertial navigation device including inertial navigation sensors mounted
on the vehicle andlor asset for generating a position vector used to determine
an
absolute vehicle andlor asset location;
a radio transmitter connected to the navigation device for transmitting the
position vector; and
a central monitoring station for receiving the position vector transmitted by
the radio transmitter.
The radio transmitter may be any type of wireless transmitter using cellular
networks, paging networks, or any other wireless radio transmission.
This system according to the present invention relies upon the typical
characteristic of inertial sensors, which is the fact that a vehiclelasset's
position or
location is the result of the original location plus the second integral of
the
longitudinal and lateral acceleration magnitudes.
The system according to the present invention is therefore autonomous and self-
contained, and does not depend upon third party infrastructures such as prior
art
vehicle tracking systems using cellular networks as disclosed in US patent No.
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5,895,436 (SAVOIE) or vehicle tracking systems employing global positioning
system (GPS) satellites for position/location determination as disclosed in US
patent No. 5,225,842 (BROWN).
The preferred inertial sensors consist of micro-machined accelerometers
manufactured using nano-technology methods, although other inertial sensors
could be used.
Preferably, the inertial sensors combined with the central station data
processing
capabilities provide location resolutions approaching 1-2 meters per
kilometer.
Absolute vehicle location may be displayed in Latitude-Longitude coordinates
and/or scrolling area maps.
According to another aspect of the present invention, there is provided a
method
for locating a vehicle andlor asset comprising the steps of:
a) mounting an inertial navigation device including inertial navigation
sensors on the vehicle and/or asset, the inertial navigation device generating
a
position vector used to determine an absolute vehicle and/or asset location;
b) transmitting the position vector by means of a radio transmitter
connected to the navigation device; and
c) receiving the position vector transmitted by the radio transmitter at a
central monitoring station.
According to yet another aspect of the present invention, there is provided a
method to control remote cut-off modules using a high frequency carrier
superimposed to the existing vehicle wiring. The cut-off modules are connected
directly to the controlled component, and controlled by superimposing a high
frequency carrier signal to the 12 Volt vehicle wiring.
Preferably, this carrier may have a frequency between 50 kHz and 500 kHz, and
is modulated by a coded signal that is used to remotely enable or disable the
cut-
off module.
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Since there is no wiring from the main control to the cut-off modules, it
becomes
very difficult to locate and disable them.
The cut-off modules may be easily disguised within the existing vehicle wiring
harnesses.
Preferably, the control signal contains digital packets that may address each
module individually, the modules answer with status and acknowledge packets
using the same communications principle.
Preferably, the remote cut-off modules contain a high frequency
receiverldemodulator that extracts the data packet from the vehicle wiring, a
rolling code data recovery circuit and a relay that is used to control,
disable and
enable the critical vehicle components.
Preferably, the modules are always in the disable mode unless enabled by the
main control unit. Therefore removing or destroying the main control unit will
not
allow the vehicle's engine to be started.
Preferably, the packets contain a progressive rolling code key to address the
remote modules. This means that every time that a module is addressed, an
algorithm within the control module firmware generates a new, different
identification code.
This process prevents would be thieves to eavesdrop the communication between
the control and remote modules, and to try to energize the modules by
emulating
the control signals.
The use of rolling code technology to address the remote modules therefore
prevents eavesdropping and the emulation of system control packets.
The invention as well as its numerous advantages will be better understood by
reading of the following non-restrictive description of preferred embodiments
made in reference to the appending drawing.
CA 02447401 2003-10-31
BRIEF DESCRIPTION OF THE DRAWING
Figure 1 is a schematic block diagram of a tracking system for locating a
vehicle
andlor asset according to a preferred embodiment of the present invention.
Figure 2 is a block diagram of a vehicle mounted unit of a tracking system
5 according a preferred embodiment of the present invention.
Figure 3 is a block diagram of wireless remote cut-off modules according to a
preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to Figure 1, the tracking system 10 for locating a vehicle andlor
asset 12
according to a preferred embodiment of the present invention includes an
inertial
navigation device 14 with inertial navigation sensors mounted on the vehicle
andlor asset 12 for generating a position vector used to determine an absolute
vehicle/asset location. The system 10 also includes a radio transmitter 16
connected to the navigation device 14 for transmitting the position vector;
and a
central monitoring station 18 for receiving the position vector transmitted by
the
radio transmitter 16.
The radio transmitter 16 may be any type of wireless transmitter using
cellular
networks, paging networks, or any other wireless radio transmission.
The tracking system 10 according to the present may also include a mobile
TrackerlFollower Vehicle, which is detailed further below.
Referring to Figure 2, the inertial navigational device 14 and radio
transmitter 16
may preferably be integrated in a vehicle mounted unit 20 containing the
following
modules:
- Legitimate User Verification module 21;
- Vehicle Movement Detector module 22;
- Engine Start Detector module 23;
- Microprocessor/System Control module 24;
- Longitudinal accelerometer module 25;
- Lateral accelerometer module 26;
- Electronic Magnetic Compass module 27; and
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- Radio Communications transceiver module 29.
As explained below, the unit 20 may contain a Radio-goniometer module 28 in
place of the Electronic Magnetic Compass module 27.
The Legitimate User Verification module 21 provides the means to identify the
user as the owner or owner authorized person, and notify the
Microprocessor/system Controller 24 accordingly.
Preferably, the Legitimate User Verification may be accomplished by means of a
biometrics fingerprint recognition module. However, other methods including
one
or the combination of the following methods may be used:
1- Pressing a button on a hand-held rolling code micro-transmitter.
2- Entering numbers on a keypad.
3- Hidden switchlmagnetic switch.
4- Voice recognition.
5- Other authorized user validation methods:
The Vehicle Movement Detector 22 can generate a signal and prompt the
Microprocessor/system Controller 24 if the vehicle 12 is moved, pushed or
towed
without authorization.
The Engine Start Detector 23 can generate a signal and prompt the
Microprocessorlsystem Controller 24 if the vehicle's engine has been started
without authorization.
The Longitudinal Accelerometer 25 can sense all positive and negative
accelerations along the vehicle's longitudinal axis, and will send the
acquired data
to the Microprocessor/System controller 24.
The Lateral Accelerometer 26 can sense all positive and negative accelerations
along the vehicle's lateral axis, and will send the acquired data to the
Microprocessor/System controller 24.
The Electronic Magnetic compass 27 can be used to determine the initial
vehicle
heading direction. Alternatively, the radio-goniometer 28 can be used to find
the
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direction of one or more known radio transmitting sources. These sources could
include a number of AM or FM stations as well as other high power known
transmitters. Thus, the radio-goniometer 28 output may also be used to
determine
the initial vehicle heading direction.
The outputs of the Longitudinal 25 and Lateral 26 accelerometers are sent to
the
Microprocessor/System Controller 24 where the vehicle instant velocity is
computed by integrating the positive and negative increments of the
acceleration
magnitudes. The Microprocessor/system Controller 24 will then integrate the
instant longitudinal and lateral velocity magnitudes over a period of time to
compute a vector that will represent the absolute vehicle displacement from
the
original location in polar coordinates.
Although not absolutely necessary for the system operation, the
MicroprocessorlSystem Controller 24 may get from time to time data from the
Electronic Magnetic compass 27 or the radio-goniometer 28 to recalibrate the
heading magnitude.
A Radio Transceiver 29 may used to transmit at predetermined intervals the
absolute displacement vectors together with the heading data to the central
monitoring station 18 using public or private radio communication channels.
Even
though the radio transmitter 16 described above can be used instead, it is
preferable to use the radio transceiver 29 as it has the advantage of being
able to
receive commands from the central monitoring station 18. It should be noted
that
high security options may include the use of spread-spectrum communications.
Although periodic radio-goniometer readings from multiple transmitting sources
alone could be used to determine vehicle position, the combination of both
inertial
and goniometer methods provides higher position resolution as well as enhanced
security.
Power for the Vehicle Mounted unit 20 may be supplied by the vehicle's 12V
battery. Alternatively, a second internal battery may be able to power the
unit 20 in
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the event that the vehicle's battery is disconnected or the wiring is cut or
tampered
with.
The purpose of the Central Monitoring Station 18 is to receive navigational
data
sent from the Vehicle Mounted Unit 20, and using computational methods, to
determine the actual location of the vehicle in question.
Data received from the Vehicle Mounted Unit 20 can be converted into
meaningful
latitude-longitude coordinates and/or a scrolling map display where the System
Administrator may follow the vehicle displacement through actual city streets,
roads and highways, in real time.
Because of the fact that the Central Monitoring Station 18 can immediately
know
that a particular vehicle has been stolen or that is being driven by a non-
authorized person, the system administrator will be able to calf the police
and
provide enough information that will allow the stolen vehicle to be
intercepted as it
is being driven away.
Upon receiving navigational data from a missing vehicle, or at a later time,
the
System Administrator may dispatch a Tracker/Follower vehicle (not illustrated)
to
an area very close to the actual location of the missing vehicle.
The Follower/Tracker Vehicle may be equipped with radio receivers and radio
direction finders that can lock onto the periodic beacon signal transmitted by
the
Vehicle Mounted Unit 20. This will allow finding and/or following the missing
vehicle until the local authorities decide upon the proper course of action to
recover the vehicle in question.
In use, under normal operatinv conditions, the system 10 is in stand-by mode,
waiting for a trigger signal to start generating vehicle displacement data.
The
authorized/legitimate user of the vehicle must normally disable the system
before
starting the vehicle's engine. The system 10 will be triggered if the
vehicle's
engine is started without prior disabling the system, or if the vehicle is
moved,
towed or pushed without authorization. This is achieved through the legitimate
user verification module 21, the movement detector module 22 and the engine
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start detector module 23. Once the system has been triggered, it will proceed
to
initialize-calibrate, reset the displacement vectors, and acquire the initial
vehicle
heading.
Different applications may require the use of the self contained electronic
magnetic compass or the self-contained radio-goniometer for spot calibration
purposes.
After initializing and calibrating, the system 10 starts transmitting a data
stream
containing the displacement vector from the original location, and in the case
of
radio-goniometer 28 equipped units, the goniometer frequency and direction
data.
The central monitoring station 18 will be instantly alerted of the vehicle 12
being
displaced without authorization, and will proceed to alert the vehicle's owner
and
local authorities.
At the same time the central station 20 may dispatch a tracking/following
vehicle
that will lock on the transmitted data stream beacon, and will help to
determine the
actual vehicle location within a few square meters. This information will be
transmitted to the local authorities in order to intercept and recover the
vehicle.
Referring to Figure 3, according to yet another aspect of the present
invention,
there is provided a method to control remote cut-off modules 30 using a high
frequency carrier superimposed to the existing vehicle wiring 31. The cut-off
modules 30 are connected directly to the controlled component 32, and
controlled
by superimposing a high frequency carrier signal to the 12 Volt vehicle
wiring.
Preferably, this carrier may have a frequency between 50 kHz and 500 kHz, and
is modulated by a coded signal that is used to remotely enable or disable the
cut-
off module 30.
Since there is no wiring from the main control to the cut-off modules 30, it
becomes very difficult to locate and disable them. The cut-off 30 modules may
be
easily disguised within the existing vehicle wiring harnesses.
CA 02447401 2003-10-31
Preferably, the control signal contains digital packets that may address each
module individually, the modules answer with status and acknowledge packets
using the same communications principle.
Preferably, the remote cut-off modules 30 contain a high frequency
5 receiverldemodulator 33 that extracts the data packet from the vehicle
wiring 31, a
rolling code data recovery circuit and a relay 34 that is used to control,
disable and
enable the critical vehicle components 32.
Preferably, the control signal is sent by an alarm unit or security module 35
which
uses a rolling code generator 36 and a high frequency modulator 37 before
being
10 transmitted via the existing wire of the vehicle 31.
Preferably, the modules 30 are always in the disable mode unless enabled by
the
main control unit. Therefore removing or destroying the main control unit will
not
allow the vehicle's engine to be started.
Preferably, the packets contain a progressive rolling code key to address the
remote modules. This means that every time that a module is addressed, an
algorithm within the control module firmware generates a new, different
identification code.
This process prevents would be thieves to eavesdrop the communication between
the control and remote modules, and to try to energize the modules by
emulating
the control signals.
The use of rolling code technology to address the remote modules therefore
prevents eavesdropping and the emulation of system control packets.
Although preferred embodiments of the present invention have been described in
detail herein and illustrated in the accompanying drawings, it is to be
understood
that the invention is not limited to these precise embodiments and that
various
changes and modifications may be effected therein without departing from the
scope or spirit of the present invention.
