 |
Claims  |
|
|
What is claimed is:
1. A stolen vehicle recovery system for enabling prompt monitoring of
unauthorized use of a vehicle, said system comprising
a vehicle transceiver means disposed on said vehicle, said vehicle
transceiver means comprising
means for transmitting a pulsed signal of length T1 seconds every T2
seconds, said transmitted pulsed signal being modulated by a data stream
comprising a unique identity code associated with said vehicle, said
vehicle transceiver means further comprising
owner verification means, said owner verification means comprising
authorization sensor means, for providing a sensor input signal from a user
of said vehicle;
deactivation means for providing an authorization signal in response to a
predetermined sensor input signal;
means for automatically initiating transmission of said pulsed signal by
said transmitting means when said authorization signal is not provided by
said deactivation means within a predetermined authorization interval;
scanning receiver means for receiving said transmitted pulsed signal and
decoding said received signal for providing a decoded signal;
control processor means for receiving said decoded signal for providing a
control signal in response thereto;
direction finding receiver means comprising remotely located direction
finding receiver means spaced apart in a pattern for enabling
triangulation detection of a dynamic position of said vehicle in a
detection area from said transmitted pulsed signal, said direction finding
receiver means comprising means for measuring the bearing, signal strength
and time variation of said bearing associated with said detected vehicle
identity code for providing said measured data to said control processor
means,
said control processor means comprising
means for verifying said identity code and providing a vehicle positional
information signal comprising said measured bearing and signal strength
data; and
means disposed at a central station and linked to said control processor
means for producing a displayable digitized street or terrain map of said
detection area with said detected vehicle position being dynamically
displayed thereon in a digitized map presentation, said digitized map
presentation being updateable as said vehicle positional information
varies, said control processor means further comprising
means for interrogating said direction finding receiver means and verifying
said vehicle identity code until said alarm condition is removed.
2. A stolen vehicle recovery system in accordance with claim 1 wherein said
system comprises means for monitoring unauthorized use of a plurality of
vehicles in said detection area, each of said vehicles having a unique
identity code associated therewith, said system further comprising a
plurality of said vehicle transceiver means, a different one of said
vehicle transceiver means being disposed on each of said plurality of
vehicles for providing said transmitted pulsed signal modulated by said
data stream comprising said unique identity code associated with said
vehicle on which said one vehicle transceiver means is disposed, said
transmitting means transmitting over a channel, a plurality of said
transmitting means transmitting on different sub-channels of said channel,
said control processor means providing a control signal to said direction
finding receiver means for tuning said direction finding receiver means in
turn to the corresponding sub-channels associated with said received
transmitted signals, said direction finding receiver means scanning the
active sub-channels in said channel with a dwell time on each of said
sub-channels of T3 seconds.
3. A stolen vehicle recover system in accordance with claim 2 wherein said
direction finding receiver means dwell time of T3 seconds is longer than
T2 seconds whereby T2 is the pulse repetition time of said vehicle
transmitting means for a given vehicle.
4. A stolen vehicle recovery system in accordance with claim 3 wherein said
scanning receiver means is continually tuned in sequence to each of said
sub-channels with a dwell time corresponding to said direction finding
receiver means dwell time, wherein each received signal is decoded and
provided to said control processor means.
5. A stolen vehicle recovery system in accordance with claim 2 wherein said
scanning receiver means is continually tuned in sequence to each of said
sub-channels.
6. A stolen vehicle recovery system in accordance with claim 5 wherein said
continually tuned scanning receiver means has a dwell time of said T3
seconds for each sub-channel
7. A stolen vehicle recovery system in accordance with claim 6 wherein said
scanning receiver means dwell time of T3 seconds is longer than said T2
seconds pulse repetition time of said vehicle transmitting means for a
given vehicle.
8. A stolen vehicle recovery system in accordance with claim 2 wherein said
central station means comprises means for dynamically displaying a
plurality of different stolen vehicle positions on said displayable
digitized street or terrain map of said detection area in said digitized
map presentation, whereby a plurality of detected vehicles in said
detection area may be simultaneously monitored on a common display map of
said area.
9. A stolen vehicle recovery system in accordance with claim 3 wherein said
central station means comprises means for dynamically displaying a
plurality of different stolen vehicle positions on said displayable
digitized street or terrain map of said detection area in said digitized
map presentation, whereby a plurality of detected vehicles in said
detection area may be simultaneously monitored on a common display map of
said area.
10. A stolen vehicle recovery system in accordance with claim 9 wherein
said scanning receiver means is continually tuned in sequence to each of
said sub-channels with a dwell time corresponding to said direction
finding receiver means dwell time, wherein each received signal is decoded
and provided to said control processor means.
11. A stolen vehicle recovery system in accordance with claim 5 wherein
said central station means comprises means for dynamically displaying a
plurality of different stolen vehicle positions on said displayable
digitized street or terrain map of said detection area in said digitized
map presentation, whereby a plurality of detected vehicles in said
detection area may be simultaneously monitored on a common display map of
said area.
12. A stolen vehicle recovery system in accordance with claim 11 wherein
said continually tuned scanning receiver means has a dwell time of said T3
seconds for each sub-channel.
13. A stolen vehicle recovery system in accordance with claim 12 wherein
said scanning receiver means dwell time of T3 seconds is longer than said
T2 seconds pulse repetition time of said vehicle transmitting means for a
given vehicle.
14. A stolen vehicle recovery system in accordance with claim 1 wherein
said transmitting means comprises means for further modulating said pulsed
signal with a code corresponding to whether said detected vehicle is
moving or stationary for providing said transmitted signal.
15. A stolen vehicle recovery system in accordance with claim 14 wherein
said system comprises means for monitoring unauthorized use of a plurality
of vehicles in said detection area, each of said vehicles having a unique
identity code associated therewith, said system further comprising a
plurality of said vehicle transceiver means, a different one of said
vehicle transceiver means being disposed on each of said plurality of
vehicles for providing said transmitted pulsed signal modulated by said
data stream comprising said unique identity code associated with said
vehicle on which said one vehicle transceiver means is disposed, said
transmitting means transmitting over a channel, a plurality of said
transmitting means transmitting on different sub-channels of said channel,
said control processor means providing a control signal to said direction
finding receiver means for turning said direction finding receiver means
in turn to the corresponding sub-channels associated with said received
transmitted signals, said direction finding receiver means panning the
active sub-channels in said channel with a dwell time on each of said
sub-channels of T3 seconds.
16. A stolen vehicle recovery system in accordance with claim 1 wherein
said vehicle transceiver means further comprises means responsive to a
remote command signal for remotely activating or deactivating said
transmitting means.
17. A stolen vehicle recovery system in accordance with claim 1 wherein
said displayed vehicle positional information in said digitized map
presentation comprises the relative position of said detected vehicle on
said map presentation and the identity of said displayed vehicle.
18. A stolen vehicle recovery system in accordance with claim 17 wherein
said system comprises means for monitoring unauthorized use of a plurality
of vehicles in said detection area, each of said vehicles having a unique
identity code associated therewith, said system further comprising a
plurality of said vehicle transceiver means, a different one of said
vehicle transceiver means being disposed on each of said plurality of
vehicles for providing said transmitted pulsed signal modulated by said
data stream comprising said unique identity code associated with said
vehicle on which said one vehicle transceiver means is disposed,
transmitting means transmitting over a channel, a plurality of said
transmitting means transmitting on different sub-channels of said channel,
said control processor means providing a control signal to said direction
finding receiver means for tuning said direction finding receiver means in
turn to the corresponding sub-channels associated with said received
transmitted signals, said direction finding receiver means scanning the
active sub-channels in said channel with a dwell time on each of said
sub-channels of T3 seconds, said identity and said relative displayed
position being provided for each detected vehicle in said detection area.
19. A stolen vehicle recovery system in accordance with claim 1 wherein
data communication with said control processor means comprises a serial
data format.
20. A stolen vehicle recovery system in accordance with claim 19 wherein
said system comprises means for monitoring unauthorized use of a plurality
of vehicles in said detection area, each of said vehicles having a unique
identity code associated therewith, said system further comprising a
plurality of said vehicle transceiver means, a different one of said
vehicle transceiver means being disposed on each of said plurality of
vehicles for providing said transmitted pulsed signal modulated by said
data stream comprising said unique identity code associated with said
vehicle on which said one vehicle transceiver means is disposed, said
transmitting means transmitting over a channel, a plurality of said
transmitting means transmitting on different sub-channels of said channel,
said control processor means providing a control signal to said direction
finding receiver means for tuning said direction finding receiver means in
turn to the corresponding sub-channels associated with said received
transmitted signals, said direction finding receiver means scanning the
active sub-channels in said channel with a dwell time on each of said
sub-channels of T3 seconds.
21. A stolen vehicle recovery system in accordance with claim 1 wherein
said direction finding receiver means further comprises one of said
measuring means disposed at said central station.
22. A stolen vehicle recovery system in accordance with claim 21 wherein
said system comprises means for monitoring unauthorized use of a plurality
of vehicles in said detection area, each of said vehicles having a unique
identity code associated therewith, said system further comprising a
plurality of said vehicle transceiver means, a different one of said
vehicle transceiver means being disposed on each of said plurality of
vehicles for providing said transmitted pulsed signal modulated by said
data stream comprising said unique identity code associated with said
vehicle on which said one vehicle transceiver means is disposed, said
transmitting means transmitting over a channel, a plurality of said
transmitting means transmitting on different sub-channels of said channel,
said control processor means providing a control signal to said direction
finding receiver means for tuning said direction finding receiver means in
turn to the corresponding sub-channels associated with said received
transmitted signals, said direction finding receiver means scanning the
active sub-channels in said channel with a dwell time on each of said
sub-channels of T3 seconds.
23. A stolen vehicle recovery system in accordance with claim 1 wherein
said antenna array in said detection area provides a plurality of
expanding coverage detection areas, said central station means comprising
means for zooming said digitized map presentation within said detection
areas.
24. A stolen vehicle recovery system in accordance with claim 23 wherein
said system comprises means for monitoring unauthorized use of a plurality
of vehicles in said detection area, each of said vehicles having a unique
identity code associated therewith, said system further comprising a
plurality of said vehicle transceiver means, a different one of said
vehicle transceiver means being disposed on each of said plurality of
vehicles for providing said transmitted pulsed signal modulated by said
data stream comprising said unique identity code associated with said
vehicle on which said one vehicle transceiver means is disposed, said
transmitting means transmitting over a channel, a plurality of said
transmitting means transmitting on different sub-channels of said channel,
said control processor means providing a control signal to said direction
finding receiver means for tuning said direction finding receiver means in
turn to the corresponding sub-channels associated with said received
transmitted signals, said direction finding receiver means scanning the
active sub-channels in said channel with a dwell time on each of said
sub-channels of T3 seconds.
25. A stolen vehicle recovery system in accordance with claim 1 wherein
said central station means comprises means for zooming said digitized map
presentation over a hierarchical geographic display area.
26. A stolen vehicle recovery system in accordance with claim 25 wherein
said system comprises means for monitoring unauthorized use of a plurality
of vehicles in said detection area, each of said vehicles having a unique
identity code associated therewith, said system further comprising a
plurality of said vehicle transceiver means, a different one of said
vehicle transceiver means being disposed on each of said plurality of
vehicles for providing said transmitted pulsed signal modulated by said
data stream comprising said unique identity code associated with said
vehicle on which said one vehicle transceiver said transmitting means
transmitting over a channel, a plurality of said transmitting means
transmitting on different sub-channels of said channel, said control
processor means providing a control signal to said direction finding
receiver means for tuning said direction finding receiver means in turn to
the corresponding sub-channels associated with said received transmitted
signals, said direction finding receiver means scanning the active
sub-channels in said channel with a dwell time on each of said
sub-channels of T3 seconds.
27. A stolen vehicle recovery system in accordance with claim 1 wherein
said direction finding receiver means comprises a plurality of antenna
arrays having overlapping detection areas.
28. A stolen vehicle recovery system in accordance with claim 27 wherein
said system comprises means for monitoring unauthorized use of a plurality
of vehicles in said detection area, each of said vehicles having a unique
identity code associated therewith, said system further comprising a
plurality of said vehicle transceiver means, a different one of said
vehicle transceiver means being disposed on each of said plurality of
vehicles for providing said transmitted pulsed signal modulated by said
data stream comprising said unique identity code associated with said
vehicle on which said one vehicle transceiver means is disposed, said
transmitting means transmitting over a channel, a plurality of said
transmitting means transmitting on different sub-channels of said channel,
said control processor means providing a control signal to said direction
finding receiver means for tuning said direction finding receiver means in
turn to the corresponding sub-channels associated with said received
transmitted signals, said direction finding receiver means scanning the
active sub-channels in said channel with a dwell time on each of said
sub-channels of T3 seconds.
29. A stolen vehicle recoverY system in accordance with claim 1 wherein
said data stream further comprises a verification code for indicating the
stolen status of the detected vehicle.
30. A stolen vehicle recovery system in accordance with claim 29 wherein
said verification code comprises a two state code, one of said
verification states being an unverified state, the other of said
verification states being a verified state in which an indication is
provided that said detected vehicle is a stolen vehicle.
31. A stolen vehicle recovery system in accordance with claim 30 wherein
said verification code is initially set to said unverified state when said
vehicle transmission is initiated.
32. A stolen vehicle recovery system in accordance with claim 31 wherein
said verification code is changed from said unverified state to said
verified state in response to detection of a remotely transmitted command
signal.
33. A stolen vehicle recovery system in accordance with claim 29 wherein
said system comprises means for monitoring unauthorized use of a plurality
of vehicles in said detection area, each of said vehicles having a unique
identity code associated therewith, said system further comprising a
plurality of said vehicle transceiver means, a different one of said
vehicle transceiver means being disposed on each of said plurality of
vehicles for providing said transmitted pulsed signal modulated by said
data stream comprising said unique identity code associated with said
vehicle on which said one vehicle transceiver means is disposed, said
transmitting means transmitting over a channel, a plurality of said
transmitting means transmitting on different sub-channels of said channel,
said control processor means providing a control signal to said direction
finding receiver means for tuning said direction finding receiver means in
turn to the corresponding sub-channels associated with said received
transmitted signals, said direction finding receiver means scanning the
active sub-channels in said channel with a dwell time on each of said
sub-channels of T3 seconds.
34. A stolen vehicle recovery system in accordance with claim 33 wherein
said verification code comprises a two state code, one of said
verification states being an unverified state, the other of said
verification states being a verified state in which an indication is
provided that said detected vehicle is a stolen vehicle.
35. A stolen vehicle recovery system in accordance with claim 34 wherein
said verification code is initially set to said unverified state when said
vehicle transmission is initiated.
36. A stolen vehicle recovery system in accordance with claim 35 wherein
said verification code is changed from said unverified state to said
verified state in response to detection of a remotely transmitted command
signal.
37. A stolen vehicle recovery system in accordance with claim 1 wherein
said vehicle transceiver means comprises a cellular telephone means.
38. A stolen vehicle recovery system in accordance with claim 2 wherein
said vehicle transceiver means comprises a cellular telephone means.
39. A stolen vehicle recovery system in accordance with claim 3 wherein
said vehicle transceiver means comprises a cellular telephone means.
40. A stolen vehicle recovery system in accordance with claim 4 wherein
said vehicle transceiver means comprises a cellular telephone means.
41. A stolen vehicle recovery system in accordance with claim 5 wherein
said vehicle transceiver means comprises a cellular telephone means.
42. A stolen vehicle recovery system in accordance with claim 17 wherein
said vehicle transceiver means comprises a cellular telephone means.
43. A stolen vehicle recovery system in accordance with claim 18 wherein
said vehicle transceiver means comprises a cellular telephone means. |
|
 |
|
 |
Claims |
|
|
|
Description |
|
|
CROSS-REFERENCE TO RELATED APPLICATIONS
The present invention is related to our commonly owned U.S. Pat. Nos.
4,651,157 and 4,791,572, naming us as joint inventor thereof, and the
commonly owned pending U.S. patent application entitled "A Method for
Accurately Updating Positional Information Provided on a Digital Map"
bearing U.S. Ser. No. 07/176,163, filed, Mar. 31, 1988, the contents of
which are specifically incorporated by reference in their entirety.
FIELD OF THE INVENTION
The present invention relates to the field of vehicle monitoring and
tracking, and more particularly to stolen vehicle recovery systems for
monitoring single or multiple stolen vehicles in a composite digitized map
display at the central station.
DESCRIPTION OF THE PRIOR ART
Vehicle tracking or monitoring systems are well known in the art, such as
disclosed in our Previous U.S. Pat. No. 4,651,157 and in U.S. Pat. No.
4,177,466. In addition, systems for accurately displaying positional
information on a map are also well known in the art, such as described in
our previous U.S. Pat. No. 4,791,572 and the co-pending U.S. patent
application Ser. No. 07/176,163 incorporated by reference herein. However,
none of the prior art systems known to applicants provides an integrated
system capable of providing a pulsed transmission unique to each vehicle
automatically initiated upon theft of the vehicle, with or without
transmission of a verification code which enables verification of vehicle
theft, or one which uses sub-channels to enable multiple vehicles to be
tracked in a single designated area such as on a common map display.
Moreover, the system described in U.S. Pat. No. 4,177,466, for example,
provides for broadcasting a continuous signal only in response to a remote
activation signal sent to a vehicle transmitter which causes the broadcast
to start. In addition, such prior art systems do not allow for tracking of
the vehicle until a command signal is first sent from a remote site,
thereby decreasing the chances of early recovery as well as the
opportunity to immediately monitor the use of the stolen vehicles, such as
its possible use in the commission of a crime, or a late night theft which
might not initially be discovered by the owner until several hours after
its occurrence. These disadvantages of the prior art are overcome by the
present invention.
SUMMARY OF THE INVENTION
A stolen vehicle recovery system is provided in which a vehicle transceiver
is disposed on each vehicle for cyclically transmitting a pulsed signal
which is modulated by a data stream comprising a verification code, a
unique identity code associated with the vehicle, and a code which
corresponds to whether the detected vehicle is moving or stationary. The
vehicle transceiver is automatically activated if the proper authorization
signal is not provided to the transceiver by a verification unit, such as
a keypad. A scanning receiver decodes the pulsed signal and provides the
information to a control processor which, in turn, sets remote direction
finding receivers, set up in a triangulation pattern, to the appropriate
channel. The direction finding receivers measure the bearing, signal
strength, and time variations, as well as the vehicle identity code, and
pass it back to the control processor. After verification of the identity
code, the control processor passes this positional information on to a
mapping and display computer located at a central station. Thereafter, the
mapping and display computer provides a digitized street or terrain map
display with the vehicle position and identity code being dynamically
displayed thereon. The map may be zoomed through a hierarchical
geographical display. The system may be used with multiple vehicles in the
same detection area with the assigned channel being divided into a
plurality of sub-channels and a composite map display dynamically showing
all stolen vehicles in the detection area. Mobile tracking may also be
used. In addition, the transceivers can be remotely activated or
deactivated, and overlapping detection areas can be provided to cover a
larger area. In order to avoid the potential for false alarms, when the
transceiver is initially activated, the verification code is set to an
unverified state and is only changed to a verified state after
confirmation of the stolen status of the vehicle, such as by checking with
the owner, and thereafter, the transmission of a command signal from the
command transmitter which changes the verification state of the
verification code.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a single area system in accordance with the
present invention;
FIG. 2 is a block diagram of a typical vehicle transceiver unit in
accordance with the present invention;
FIG. 3 is a block diagram of a typical scanning receiver in accordance with
the present invention;
FIG. 4 is a block diagram of a typical direction finding receiver station
in accordance with the present invention;
FIG. 5 is a block diagram of a typical mobile target tracker that may be
used in accordance with the present invention;
FIG. 6 is an illustrative diagram of typical coverage of a typical fixed
site system in accordance with the present invention;
FIG. 7 is an illustrative diagram of a large area system using four three
station systems of the type illustrated in FIG. 6 in accordance with the
present invention;
FIG. 8 is a block diagram, similar to FIG. 1, illustrating the system
layout, similar to FIG. 1, for use with the large area system of FIG. 7 in
accordance with the present invention; and
FIG. 9 is an illustrative diagram of the overall stolen vehicle recovery
network of the present invention employing owner verification of the
stolen vehicle.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings in detail and initially to FIG. 1, a block
diagram of a typical single area sytem in accordance with the present
invention is shown and is generally given reference numeral 20. As shown
and preferred in FIG. 1, the basic system 20 preferably includes a central
station 22, and a pair of out stations 24 and 26 which, as will be
described in greater detail hereinafter, together with central station 22,
enable triangulation to detect the position of a stolen vehicle, such as
the vehicle represented by reference numeral 28 in FIG. 1. Each vehicle 28
in the system 20 is preferably fitted with a commandable vehicle
transceiver unit 30, to be described in greater detail hereinafter. The
transceiver unit 30 is preferably able to recognize a legitimate or
authorized driver through deactivation methods. If an unauthorized driver
is using the vehicle 28, then the transmitter 32 (FIG. 2) contained in the
vehicle transceiver unit 30 is preferably initially automatically
activated. The transmitted signal which is then provided from the vehicle
transceiver unit 30, such as diagramatically represented by signals 34,
36, and 38 in FIG. 1, is preferably modulated by a data stream which
includes the vehicle identity code, which is preferably unique to each
vehicle in the system 20, a verification of stolen code, a movement code,
and a relay contact condition code. With respect to the verification code,
when the transceiver unit transmitter 32 is initially activated by a
failure to disarm the vehicle sensor, it isn't the verification code is
set to an unverified state. Verification of the stolen status of the
vehicle 28 may then be confirmed by prompt, direct contact with the
vehicle 28 owner, such as illustrated in FIG. 9 by reference numberal 23.
Once it has been confirmed that the vehicle 28 has been stolen, a command
may then be sent from the command transmitter 52 at the central station
22, via, the command and control processor 40, which then sets the
verification code to a verified state indicating that vehicle 28 has been
stolen. Of course, if no such verification is needed in the system 20,
then this procedure may be omitted and the data stream used to modulate
the transmitter 32 can omit transmission of a verification code so that
the vehicle 28 will automatically be tracked as a stolen vehicle from its
inception of the transmission from transceiver unit 30. In either event,
the initial transmission can also initiate a recording of the tracking of
the vehicle 28 so that the central station 22 may have a permanent stored
record of the vehicle 28 movement until such time as the status of the
vehicle 28 is confirmed as stolen. Thereafter, the entire tracking history
of the vehicle 28 can be displayed from the time that the vehicle 28 was
initially moved from its original location. This would facilitate locating
vehicles 28 whose confirmation of theft does not occur until several hours
or days after the theft or would assist in tracking the use of stolen
vehicles 28 in a crime if such use occured before the vehicle 28 was
reported as stolen. These advantages are not possible in prior art
systems, such as the prior art system described in U.S. Pat. No.
4,177,466.
The modulated signal transmitted from the vehicle 28 via the vehicle
transceiver unit 30, is preferably picked up by the scanning receiver 42
which decodes the signal and passes the information on to the command and
control processor 40 by direct line or radio link. The command and control
processor 40 then preferably sets the three direction finding receivers
44, 46, and 48 to the appropriate channel to monitor the movement of the
vehicle 28. The direction finding receivers or DF receivers 44, 46, 48
preferably measure the bearing, the signal strength, the time-variation or
confidence of the bearing, as well as the unique identity code of the
detected vehicle 28 which, after confirmation and change of state of the
verification code, may be designated as a stolen vehicle. This information
is then passed on to the command and control processor 40 again by direct
line or radio link. The command and control processor 40 then preferably
verifies the unique identity code of the vehicle 28 and passes the bearing
and signal strength details on to the mapping and display computer 50,
such as the type of mapping and display computer 50 described in our prior
U.S. Pat. No. 4,791,572, the contents of which are specifically
incorporated by reference herein, and in our co-pending U.S. patent
application Ser. No. 07/176,163 entitled "A Method For Accurately Updating
Positional Information Provided On A Digital Map", the contents of which
are also specifically incorporated by reference herein. As described in
the aforementioned patent and patent application, the mapping and display
computer 50 preferably plots the location of the detected or stolen
vehicle 28. The description and details of the vehicle 28 and the owner
are preferably obtained from the data base of the mapping and display
computer 50 and can be used to contact the owner and verify that the
vehicle 28 has been stolen and to pass information on to the police
department and mobile tracking units if such units are employed in the
system 20. Once verified that the vehicle 28 is stolen, as previously
mentioned, the verification code is set to the verified state and a direct
link may be established with police dispatch and a mobile tracking unit or
units can be directed to the location. Each mobile tracking unit, such as
shown in FIG. 5, is preferably equipped with a direction finding system
which indicates the bearing of the vehicle transceiver 30 as well as the
identity code. Once located and apprehended, the vehicle transmitter 32
can be remotely switched off, if desired, by the command transmitter 52
which is controlled by the operator at the central station 22 via the
command and control processor 40 which controls the command transceiver
52.
Referring now to FIG. 2, a block diagram of a typical vehicle transceiver
unit 30 is shown. The vehicle transceiver unit 30 is preferably a
commandable target which can be controlled by the command transceiver 52
at the central station 22 to switch the transceiver 30 on and off.
Normally, however, the transceiver 30 is only activated when the owner
verification circuit 68 detects that an unauthorized driver is using the
vehicle 28. When activated, the transceiver 30 transmits a pulsed signal
of length T1 seconds every T2 seconds. The transmitted signal from the
transmitter 32, as was previously mentioned, is preferably modulated by a
unique vehicle identity code, the verification code, and a code which
corresponds to whether the vehicle 28 is moving or stationary. In
addition, a relay contact condition code may also be provided in the data
stream which is used to modulate the transmitter 32. When not
transmitting, the receiver section 60 of the vehicle transceiver unit 30
is preferably active and can be used to remotely control the actions of
the vehicle transceiver unit 30. Coded signals from the command
transmitter 52 at the central station 22 are preferably able to activate
or deactivate the pulsed transceiver 30. As an option, if desired, relay
contacts can be remotely closed or opened by command which can be used,
for example, for several functions such as deactivating the vehicle 28
engine, illuminating a light, sounding an alarm, etc. In such an instance,
the aforementioned relay contact condition code would be part of the data
stream used to modulate the transmitter 32. The vehicle transceiver unit
30 has the transmitter 32 and the receiver 60 preferably on the same
frequency channel and they share a common antenna input 62. Preferably,
the vehicle transceiver unit 30 is concealed on the vehicle 28 and is able
to be powered by internal batteries and/or the vehicle battery supply. As
is further shown and preferred in FIG. 2, vehicle transceiver unit 30 also
comprises a processor 64, a movement detector circuit 66, an owner
verification circuit 68, the optional relay contacts 70, and, of course, a
power circuit 72.
Referring now to FIG. 3, a block diagram of a typical scanning receiver 42
is shown. The scanning receiver 42, on a continual basis, is tuned in
sequence to each of the sub-channel frequencies in the system 20. The
dwell time on each channel T3 is preferably slightly longer than time T2,
which is the vehicle transceiver unit 30 pulse repetition time. If a
signal is received by the scanning receiver 42, it is preferably decoded,
and the details of the resulting code and the channel are sent on to the
command and control processor 40 at the central station 22. As shown and
preferred in FIG. 3, the scanning receiver 42 preferably comprises an
antenna 70, a receiver circuit 72, a local oscillator circuit 74, a
demodulation circuit 76 connected to the receiver circuit 72, a timing
circuit 78 connected to the local oscillator circuit 74, and a control
circuit 80.
The command and control processor 40, is preferably the central focus of
the system 20 and follows a sequence of events in order to check and
locate the stolen vehicle 28 with the command and control processor 40
preferably being a conventional micro computer based unit, conventionaly
programmed in order to accomplish this function. The prefered sequence of
events is as follows. The code and channel detail of an active vehicle
transceiver unit 30 are, as was previously mentioned, preferably received
from the scanning receiver 42. The command control processor 40 then
preferably checks whether the received signal relates to a newly active
vehicle transceiver unit 30 or one that it has been previously tracking.
If the received signal relates to a newly active vehicle transceiver unit
30, then the identity code associated with the vehicle transceiver unit 30
is sent to the mapping and display computer 50 which, as was previously
mentioned, is a conventional computer, conventionaly programmed to carry
out the mapping and display function. The direction finding receivers 44,
46, 48 are then preferably set by the command control processor 40 to the
corresponding channel frequency associated with the newly active vehicle
transceiver unit 30. The direction finding receivers 44, 46, and 48 are
then interrogated by the command and control processor 40 and, in response
to such interrogation, respond with the code associated with the vehicle
28 identity and the associated movement code indicating whether the
vehicle 28 is stationary or moving, the bearing, the signal strength and
the confidence of their respective received signals.
In addition, the verification code is initially received and is set to
unverified as was previously mentioned. Verification of the stolen status
of the newly active vehicle transceiver unit 30 is then confirmed by
prompt, direct contact with the vehicle 28 owner, by way of example. Once
it has been confirmed that the vehicle 28 has been stolen, a command is
then sent from the command transmitter 52 which sets the verification code
to verified. In addition, the command and control processor 40, checks the
identification code and if they correspond to a previously identified
active transceiver unit 30, the full details are passed on to the mapping
and display computer 50. As previously, mentioned, this information may
also be passed on to the police dispatch mapping and display computer such
as illustrated by reference numeral 25 in FIG. 9, but, preferably, this is
only accomplished after customer verification 23 and the change of the
verification code from an unverified state to a verified state so as to
eliminate the possibility of false alarms. Of course, if desired, police
vehicles 27 may be equipped with mobile target trackers, which, if within
range of an active vehicle transceiver unit 30, could display the bearing,
identification code and verification code status of the vehicle 28. Thus,
the policeman would know whether the vehicle 28 had been confirmed as
being stolen or not and would have the option of either tracking the
vehicle 28 or not. In addition, the verification code, if desired, could
be used by a mobile tracking unit so as to inhibit any display if the
verification code was in an unverified state so that nothing would appear
on the monitor. If desired, the verification code status could be
identified using colored lights such as a green LED for a verified state
and a red LED for an unverified state. With respect to the command and
control processor 40 itself, however, preferably this unit 40 will
continue to track the vehicle 28 whether it is verified or unverified and
will continue to repeat the steps of interrogating the direction finding
receivers 44, 46 and 48, checking the identification codes of the received
signals, and passing this information on to the mapping and display
computer 50 for appropriate display and mapping of the vehicle 28 being
tracked. Thus, during the period of time that the vehicle transceiver unit
30 is transmitting in an unverified state, the system 20 could record and
store data concerning the location and movement of the vehicle 28 without
initially providing this information to police dispatch unless requested.
If the vehicle 28 is later confirmed to have been stolen, the data
concerning the recent whereabouts of the vehicle 28 can be useful to the
police in linking the vehicle 28 to crimes that may have been committed
and to suspects.
If more than one vehicle transceiver unit 30 is active, then the command
and control processor 40 will set the direction finding receivers 44, 46
and 48, in turn, preferably to the corresponding channels which, as
previously mentioned are in reality sub-channel frequencies in the system
28. The direction finding receivers 44, 46 and 48 preferably effectively
scan the active channels, dwelling for T3 seconds on each active channel.
The details of all of the received signals on each channel are preferably
sent to the command and control processor 40. By checking the identity
codes, the command and control processor 40 is preferably able to identify
clashes between different vehicle transceiver unit 30 transmissions that
are sharing a common channel. Under operator control, the command and
control processor 40 also preferably controls the operation of the command
transmitter 52 which, when desired, can be set to an appropriate channel
and data passed to it corresponding to codes which, when transmitted, will
cause a chosen vehicle transceiver unit 30 to be controlled, such as to
turn the transmitter 32 on or off, or to turn relay contacts 70 on or off.
The command transmitter 52 is preferably, as previously mentioned, to
remotely control functions of the vehicle transceiver unit 30. It is used,
under operator control, primarily as a means of turning its associated
transceiver unit 30 off when the stolen vehicle 28 has been recovered, but
can also be used to switch the transmitters 32 on and off if desired, as a
means of controlling the contention or clashing of the transmissions from
the vehicle transceiver units 30. For example, if two vehicle transceiver
units 30 are active on a common channel, they may be switched on and off
in order to simplify the operations. The address code for the vehicle
transceiver unit 30 will preferably differ from the vehicle identity code
for security reasons.
The mapping and display computer 50 is preferably based on the computerized
mapping and interactive database used by Mets Inc., the assignee of this
application, in its commercially available Fleet Management System, and
such as described in the aforementioned U.S. Patents and copending Patent
Application commonly owned by Mets Inc., incorporated by reference herein.
The identity code of the active vehicle transceiver unit 30, as was
previously mentioned, is passed on to the mapping and display computer 50.
Suffice to say that the data base, as is used in the commercially
available METS computerized mapping and interactive data base Fleet
Management System, is interrogated and the full details of the vehicle 28
and the owner are presented to the operator. Normally, attempts would then
be made to contact the owner of the vehicle 28 so as to verify that an
unauthorized person is driving the | | |
