ANTI-THEFT SYSTEM FOR A VEHICLE

Abstract: A system for preventing the unauthorized use of a vehicle comprises a stationary unit (1) mounted in a vehicle and comprising a controller (2) connected to sensors (3), actuators (6), a receiver (9) and a transmitter (10). The receiver (9) and transmitter (10) are connected to a common inductance coil (11). A user carries a portable unit (12), comprising a transmitter (14) and a receiver (13) which are each connected to a common inductance coil (15) that interacts with the inductance coil (11) of the stationary unit (1). The stationary coil (11) is installed in a secure place in the vehicle such that the interaction area of the coils covers at least a part of one of the seats in the passenger compartment or driver's cab.

Description: Anti-theft system for a vehicle The present invention relates to an anti-theft system which prevents the unauthorized use of a vehicle, and is of particular applicability to cars. A known anti-theft system, disclosed in US Patent No. 5,280,267 includes a stationary part installed in a vehicle and comprising a controller connected to the engine ignition key, an engine disabling device, a first receiver and a first transmitter. The first receiver is connected to a first antenna and the first transmitter is connected to a first inductance coil. This system further includes a portable part, comprising a second transmitter having a second antenna and connected to a second receiver having a second inductance coil which is able to interact with the first inductive coil. However, this system requires a self-contained power supply in the portable part and two transmit /receive channels that operate at different frequencies. One of the channels, associated with the first and second antennas, operates by means of radio communication. This system is complicated and expensive. In addition, radio communication does not provide sufficient protection against unauthorized interception of signals, and thus reduces the security of the system. According to US Patent No. 5,280,267 the portable part is carried with the vehicle ignition key. Such a system only operates at very close proximity when the key is inserted in the lock. In addition, the electronic security device and the mechanical security device, i.e. the key, are permanently connected such that anyone in possession of the key can use the vehicle. The object of the present invention is to provide a vehicle anti-theft system which does not suffer from at least some of the above-mentioned drawbacks, that is simple, low in cost, and offers improved vehicle protection against unauthorized usage. To this end, the present invention provides an anti-theft system for a vehicle comprising: a stationary part installed in the vehicle and comprising a first inductance coil and a controller connected to at least one sensor and at least one actuator, a first receiver and a first transmitter; and a portable part, comprising a second transmitter, a second receiver and a second inductance coil capable of electromagnetic interaction with the first inductance coil, wherein the input of the first receiver and the output of the first transmitter are connected to the first inductance coil, and the input of the second receiver and the output of the second transmitter are connected to the second inductance coil. Thus, the invention has the advantage over the prior art that only a single inductance coil is required for each of the stationary part and the portable part, thereby providing a cheap and simple construction. In addition, the inductive interaction of the first and second induction coils will, in general, be of a shorter range than radio communication and will tend to be shielded from reception outside the vehicle by the metallic vehicle body, thereby preventing unauthorised interception of the portable unit signal from outside the vehicle. Preferably, the portable unit is a passive device which is powered by the stationary unit through the inductive interaction, such that the portable unit does not require its own power source. Preferably, inductive interaction takes place between the stationary and portable units when they are physically remote from each other, in particular so that the user may carry the portable unit on his or her person, for example in a pocket or wallet, and the system will operate successfully while the user is seated in the car, without the need for removing the portable unit from the pocket. In this way, the ignition key and the portable unit may be kept separate, thereby increasing the security of the vehicle against unauthorised use. In a particularly preferred arrangement, the first inductance coil is positioned such that inductive interaction may take place when the portable unit is located at any position in the region of the user's seat. The first inductance coil may be mounted in a secure place within an expected area of interaction with the second inductance coil, moreover this area may extend over at least a section of one of the seats in the passenger compartment or in the driver's cab, the user's seat in particular. The first inductance coil may be installed: - in the back of a seat with an electrically open- ended frame, in particular along the perimeter of the seat,- - in the cover of a hatch or sunroof on the roof of the passenger compartment or of the driver's cab and made of a dielectric material; - in the roof of the passenger compartment or of the driver's cab made of a dielectric material, in particular, along the roof perimeter or in the area above the user's chair; - in a door of the passenger compartment or of the driver's cab made of a dielectric material, in particular, along the perimeter of its non-glass part; - in the instrument panel, in particular, along its perimeter; - on the cover of a seat in the passenger compartment or in the driver's cab, in particular, along the back of the seat; - on a massage mat that is placed on a seat in the passenger compartment or in the driver's cab and is in the form of an array of beads linked by flexible thread¬ like elements passing through holes in the beads, with all elements of the array made of a dielectric material, and the inductance coil passing through the holes of the beads, in particular, along the perimeter of the seat back. All of the elements of the portable unit may be embedded in a plastic card, with the second inductance coil positioned along the card perimeter. Embodiments of the invention will now be described by way of example only and with reference to the accompanying drawings, in which: Fig. 1 is a block diagram of an anti-theft system according to the invention,- Fig. 2 is a schematic circuit diagram of the controller of the system of Figure 1; Fig. 3 is a block diagram of the transmitter and the receiver of the stationary unit of the system of Figure 1,- Fig. 4 is a schematic circuit diagram of the portable unit of the system of Figure 1; Fig. 5 is a view of the inductance coil of the stationary unit of the system of Figure l embedded in the back of a front seat of a vehicle, the seat shown with its cover removed; Fig. 6 is a partial sectional view of the inductance coil of the stationary unit of the system of Figure l embedded in the sunroof of a vehicle,- Fig. 7 is a partial sectional view of the inductance coil of the stationary unit of the system of Figure 1 embedded in the roof of a vehicle,- Fig. 8 is a partial sectional view of the inductance coil of the stationary unit of the system of Figure l embedded in the door of a vehicle,- Fig. 9 is a partial sectional view of the inductance coil of the stationary unit of the system of Figure 1 embedded in the instrument panel of a vehicle; Fig. 10 is a partial sectional view of the inductance coil of the stationary unit of the system of Figure l fixed on a cover of a front seat of a vehicle; Fig. 11 is a view of the inductance coil of the stationary unit of the system of Figure 1 mounted on a massage mat of a seat of a vehicle. Referring to Figure l of the drawings, a vehicle anti-theft system according to the invention includes a stationary unit 1 installed in a vehicle, comprising a controller 2 and connected to the controller: sensors 3, in particular, ignition lock 4 and door pin switches 5; actuators 6, in particular, a siren 7 and an ignition blocking relay 8; a receiver 9 and a transmitter 10 connected to a common inductance coil 11. The system further comprises a portable unit 12, comprising a receiver 13 and a transmitter 14 that are connected to each other and have a common inductance coil 15. The components of the stationary unit are connected to an external power supply 16, in particular, to the accumulator of the vehicle, directly or, if necessary, through a secondary power supply 17. The controller 2 as shown in Figure 2 comprises a microcontroller 18, e.g. of the ZILOG Z86E0812 type (USA), that is connected as follows: to an EEPROM 19, e.g. of the Microchip 93C46 type (USA); to a quartz resonator 20, e.g. of the PH02 type (Russia) having a 4.43 MHz frequency, and capacitors 21, 22,- to a voltage divider consisting of resistors 23, 24 and a capacitor 25; through an inverter 26, e.g. of the 1554J1H1 type (Russia) , to a voltage divider consisting of resistors 27 and 28 and a capacitor 29; through a resistor 30 to the base of a transistor 31, e.g. of the KT829 type, with its emitter connected to a grounded resistor 32; through a resistor 33 to the base of a transistor 34, e.g. of the KT3102 type, with its emitter connected to a grounded resistor 35; to grounded filter capacitors 36 and 37. The transmitter 10 as shown in Figure 3 comprises a generator 38, with its input connected to the power supply 17 via an electronic key 39 the input of which is linked to the microcontroller 18 and the output of which is linked through an inverting amplifier 40 and a non¬ inverting amplifier 41 to a capacitor 42 and the coil 11 connected in series. The receiver 9 also shown in Figure 3 comprises a detector 43, with its input connected to one end of the coil 11, and its output connected, through low-pass filters 44,45, to a comparator 46, the second input of which is connected to the output of filter 44, and the output of which is connected to the microcontroller 18. The receiver 13 as shown in Figure 4 includes a stabilizing diode 47 with its cathode connected to one lead of a capacitor 48 and to the cathode of a diode 49, the anode of which is connected to one lead of a capacitor 50 and one lead of the coil 15. The anode of the stabilizing diode 47 is connected to the other leads of the capacitors 48,50 and the coil 15. The receiver 14 includes a multiplexer 51, e.g. of the K561-KII2 type (Russia) , with its address inputs connected to the outputs of a counter 52, e.g. of the K561HE10 type (Russia) . The common pins of the multiplexer 51 and the counter 52 are connected to the anode of the stabilizing diode 47, and their power supply inputs are connected to its cathode. The multiplexer 51 output is linked to the cathode of a diode 53, the anode of which is connected through a resistor 54 to the anode of the diode 49, which is also linked to the counter 52 input through a resistor 55. It will be apparent to the skilled person how to construct those components not described in detail above. For example, the power source 17 can be implemented using regulators and voltage converters, see, for example, "750 Practical Electronic Circuits: Handbook" - M. : Mir, 1986, p. 30, 31, 33. The electronic key 39 may also be implemented in a known way such as the power control circuit described at p. 451 of "750 Practical Electronic Circuits". The filters 44,45, the detector 43 and the generator 38 may all be implemented using circuits described in Gusev et al. "Electronics: Text-book for Institutes" - M. : Vysshaya Shkola 1991, Fig. 6.25.a, 6.50, 8.38 respectively. The amplifiers 40, 41 and the comparator 46 may be implemented using circuits described in "Integrated Circuits: Operational Amplifiers". Vol. 1. - M. : Physmatlit., 1993, p.69. The inductance coil 11 may be implemented and installed in several different ways, as described below. The coil 56 may be installed in one of the seats of a vehicle, in particular, along the perimeter of the back of the user's seat, as shown in Figure 5. If the frame 57 of the seat back is made of a conductive material, it is necessary to open it electrically by replacing a section of the seat back with a member 58 of dielectric material to preserve the mechanical strength of the seat. When the seat contains conductive springs 59, one end of them may be fixed to the frame 57 using dielectric rings 60 to electrically isolate the seat. In a second implementation shown in Figure 6, a coil 61 is embedded in the cover 62 of a sunroof in the roof 63 of a vehicle and made of a dielectric material. In a third implementation shown in Figure 7, a coil 64 is embedded along the perimeter of the vehicle roof 65 made of a dielectric material, or in the roof area above, in particular, the user's seat (not shown) . In a fourth implementation shown in Figure 8, a coil 66 is embedded in a vehicle door 67, made of a dielectric material, in particular, along its perimeter. In a fifth implementation shown in Figure 9, a coil 68 is positioned on the inner surface of an instrument panel 69, in particular, along its perimeter. In a sixth implementation shown in Figure 10, a coil 70 is fixed on a cover 71 of a seat, in particular along the perimeter of its back 72. In a seventh implementation shown in Figure 11, a coil 73 is fixed on a massage mat positioned on a seat in the form of an array of beads 74 linked by flexible threads 75 passing through holes in the beads. The bead and threads 74, 75 are made of a dielectric material. The inductance coil 73 goes through the holes of the elements 74, positioned, in particular, along the perimeter of the seat back 76. All elements 13, 14, 15 of the portable unit 12 can be embedded into a plastic card, such as a credit-card type, and the coil 15 can be positioned along the perimeter of the card. In the initial position, the ignition system of the vehicle is deactivated by the lock 4, the controller 2 is connected to the power source 17, the microcontroller 18 has stored in its memory the system operation algorithm, and the memory 19 of the stationary unit stores the code for the portable unit that is set by jumpers 77 between selected information inputs and the common pin of the multiplexer 51. The oscillating loop 15, 50 of the portable unit 12 is pre-tuned to the frequency F of the generator 38 of the stationary unit 1. The user carrying the portable unit 12 and an ignition key for the lock 4 is outside the vehicle. The anti-theft system operates in the following way. The user sits in the seat, in the back of which, in one implementation, the inductance coil 11 is installed (56 in Fig. 5) . In doing so, he brings the portable unit 12 which is, for example, in his pocket, into the interaction area of the coils 15 and 11. When the key is inserted into the ignition lock 4 and turned, the contacts close. The voltage derived from the accumulator 16 is applied through the divider 27, 28, 29 and the inverter 26 to the microcontroller 18 and this switches the microcontroller to the "Guard" mode of operation. In this mode, the microcontroller starts counting the time T specified for identification of the portable part 12, e.g. T=15s, and provides a control signal to the electronic key 39 of the transmitter 10, that connects the generator 38 of the transmitter 10 to the power source 17. Oscillations at the frequency F, e.g. 120 KHz, pass from the generator 38 through the amplifiers 40, 41 to the oscillating loop 11, 42 of the stationary unit l having a resonance frequency F. An alternating voltage of frequency F is induced in the oscillating loop 15, 50 of the portable unit 12. After rectification by the diode 49, filtration by the capacitor 48 and limitation by the stabilizing diode 47 of the receiver 13, this voltage powers the counter 52 and the multiplexer 51 of the transmitter 14. At the same time, the voltage frequency F from the loop 15, 50 is applied through the resistor 55 of the transmitter 14 to the input of the counter 52. During its cycling operation the counter 52 polls sequentially the information inputs of the multiplexer 51, and this represents a variable load on the coil 15. The value of this load as well as the current through the coil 15 are determined by the presence or absence of jumpers 77. The diode 53 protects the multiplexer from overvoltage, and the resistor 54 limits the power passing through it. The value of current in the coil 15 of the portable unit 12, that varies according to the code set by the jumpers 77, changes the voltage in the coil 11 of the stationary unit 1, i.e. performs an amplitude modulation of the signal with a carrier frequency F. This signal is processed by the detector 43 and the filter 44 in the receiver 9, and the resulting envelope is compared with the average value of the filter 45 output signal by the comparator 46. The code of the portable unit 12 is obtained at the output of the comparator 46, and is then passed to the microcontroller 18, where it is compared with the specified code of the portable unit 12 stored in the memory 19. If the two codes coincide within the period of time T, the microcontroller returns from the "Guard" mode of operation to the initial position. If, later on, at least one of the door pin switches 5 become activated with the ignition system turned on, for example in the event of a "carjacking", then the voltage from the accumulator 16 through the divider 23, 24, 25 is applied to the microcontroller 18 and switches it to the "Guard" mode again. If at any time the codes fail to match, for example when the portable unit 12 is not present during the period of time T, then the microcontroller 18 leaves the "Guard" mode and enters the "Alarm" mode. In this mode, the microcontroller provides control signals to the actuators 6, in particular through the power amplifier 30, 31, 32 to the siren 7 to produce a warning alarm for a specified period of time, for example 30 s, and through the power amplifier 33, 34, 35 to the ignition blocking relay 8 to prevent the vehicle from movement. The microcontroller also passes signals to the electronic key 39 of the transmitter 10, to maintain the possibility of identifying the portable unit 12. The switching of the microcontroller 18 from the "Alarm" mode to the initial position is performed by identification of the portable unit 12 in the same way as described above for the switch from the "Guard" mode. The controller 2 may, of course, operate according to alternative operating algorithms of the anti-theft system, besides the above-mentioned ones. Operation of the anti-theft system in accordance with the other implementations mentioned above is similar to the described one. Although, a particular electronic arrangement suitable for carrying out the invention has been described, this is not intended to be limiting. It will be clear to the skilled person that there exist a large number of possible electronic arrangements which would be suitable for putting the invention, as defined by the appended claims, into practice. Indeed, one system which may be adapted for use in accordance with the invention is the Texas Instruments Registration and Identification System (TIRIS) available from Texas Instruments, USA. Furthermore, although inductance coils having air cores have been described, it would also be possible for inductance coils with, for example ferrite, cores to be used with this system, particularly for the inductance coil of the stationary unit. This would have the advantage of allowing the antenna of the stationary unit to be reduced in size while maintaining the same effective range. Compared to the prior art devices, the proposed anti-theft system is less complicated and less expensive, due to the absence of a radio channel and a self-contained power supply in the portable unit, as well as more secure due to a reduced possibility of signal interception.

Claims: Claims 1. An anti-theft system for a vehicle comprising: a stationary part installed in the vehicle and comprising a first inductance coil and a controller connected to at least one sensor and at least one actuator, a first receiver and a first transmitter; and a portable part, comprising a second transmitter, a second receiver and a second inductance coil capable of electromagnetic interaction with the first inductance coil, wherein the input of the first receiver and the output of the first transmitter are connected to the first inductance coil, and the input of the second receiver and the output of the second transmitter are connected to the second inductance coil . 2. A system as claimed in claim 1 wherein the portable unit is adapted to be carried by a user separately from the key of the vehicle. 3. A system as claimed in claim 1 or 2 , wherein the portable unit is a passive device which is powered by the stationary unit by means of electromagnetic interaction. 4. A system as claimed in any preceding claim wherein the region of interaction between the first and second coils extends at least partially over a region occupied by a carrier of said portable part. 5. A system as claimed in any preceding claim, wherein the first inductance coil is mounted in a secure place within the area of its interaction with the second induction coil. 6. A system as claimed in claim 4 or 5, wherein said interaction region covers at least a part of one of the seats inside the passenger compartment or the driver's cab of the vehicle. 7. A system as claimed in claim 6, wherein said interaction region covers at least a part of the user's seat . 8. A system as claimed in claim 7, wherein said first inductance coil is embedded in the back of the user's seat. 9. A system as claimed in claim 8, wherein the user's seat has an electrically open or isolated frame. 10. A system as claimed in claim 7, wherein said first inductance coil is mounted along the perimeter of the back of the user's seat. 11. A system as claimed in claim 7, wherein said first inductance coil is fixed to a cover of the user's seat. 12. A system as claimed in claim 11 wherein said first inductance coil is mounted along the perimeter of the cover located on the back of the user's seat. 13. A system as claimed in claim 6 or 7, wherein said first inductance coil is fixed to a massage mat of dielectric material on a vehicle seat. 14. A system as claimed in claim 13, wherein said first inductance coil passes through the central holes of beads along the perimeter of the massage mat . 15. A system as claimed in any of claims 4 to 7, wherein said first inductance coil is embedded in the roof, made of a dielectric material, of the passenger compartment or of the driver's cab. 16. A system as claimed in claim 15, wherein said first inductance coil is mounted along the perimeter of the roof of the passenger compartment or of the driver's cab. 17. A system as claimed in claim 15 or 16, wherein said first inductance coil is embedded in the roof area above the user's seat. 18. A system as claimed in any of claims 4 to 7, wherein said first inductance coil is embedded in the cover of a sunroof or hatch, made of a dielectric material, on the roof of the passenger compartment or the driver's cab. 19. A system as claimed in any of claims 4 to 7, wherein said first inductance coil is embedded in a door of the passenger compartment or driver's cab made of a dielectric material . 20. A system as claimed in claim 19, wherein said first inductance coil is mounted along the perimeter of the non-glass part of the door of the passenger compartment or the driver's cab. 21. A system as claimed in any of claims 4 to 7, wherein said first inductance coil is embedded in the instrument panel of the vehicle. 22. A system as claimed in claim 21, wherein said first inductance coil is mounted along the perimeter of the instrument panel . 23. A system as claimed in any preceding claim, wherein said portable unit is in the form of a plastic card. 24. A system as claimed in claim 23, wherein said second inductance coil is positioned along the perimeter of the plastic card. 25. An anti-theft system for a vehicle comprising a stationary unit installed in the vehicle and a portable unit carried by a user of the vehicle separately to the vehicle key, the system operating to activate an alarm and/or disable the vehicle in the event that the presence of said portable unit is not sensed by the stationary unit during operation of the system.

Inventors: SHEPTOVETSKY ALEXANDRE YURIEVI, VASILIEVICH IVLEV SERGEY, SHEPTOVETSKY, ALEXANDRE YURIEVICH, VASILIEVICH, IVLEV SERGEY
Applicants: GEOSOFT EASTLINK GEOLINK, LECKEY DAVID HERBERT, SHEPTOVETSKY ALEXANDRE YURIEVI, VASILIEVICH IVLEV SERGEY, GEOSOFT-EASTLINK (GEOLINK), LECKEY, DAVID, HERBERT, SHEPTOVETSKY, ALEXANDRE YURIEVICH, VASILIEVICH, IVLEV SERGEY
Application year: 1996
Main classification: B60R25
IPC codes: B60R25, H01Q1, H01Q7