Patent Application
20070200688
The present invention relates to a security system for vehicles which are parked in a predefined area, such as a car park.
A variety of vehicle security devices exist. Most new vehicles include anti-theft devices such as built-in alarms to indicate an unauthorized event such as a door, window or hood being forced open or tampered with. These alarms typically use an audible signal and flashing lights to alert others of the unauthorized entry. More complicated systems employ immobilisers which seek to prevent the vehicle from being operated without the appropriate key, and use a fuel or other type of cut-out to physically immobilise the vehicle.
With constant exposure to car alarms the public take little, if any, notice of such alarms these days. Many of these simple systems are therefore, regrettably, of limited deterrence to vehicle theft or tampering.
More sophisticated systems employ a vehicle tracking functionality generally requiring the vehicle to be fitted with a transceiver which transmits a signal to a tracking receiver allowing the vehicle location to be identified. Such signals are generally via a radio frequency communication, and may also interact with in-vehicle devices such as immobilisers to allow remote vehicle control.
One area where there are particular difficulties in providing security for vehicles, and yet where it should be feasible to do so, is where vehicles are parked in car parks. Car parks, especially multi-storey car parks, commonly have areas where people can tamper with vehicles relatively unnoticed. On the other hand, by their very nature, car parks are defined areas typically with a single or very small number of vehicle exit points.
It has previously been proposed to use a radio-frequency based monitoring system adapted for specific use within a car park environment. An example of such a system is discussed in U.S. Pat. No. 4,990,890.
Such radio-frequency based systems are however nonetheless susceptible to malicious attack, in that it is relatively easy to obtain devices which can locally interrupt radio frequency communication by emitting a jamming signal, such as high amplitude white noise.
The present invention seeks to provide a vehicle security system for providing effective security and enhanced functionality over existing systems.
According to the present invention there is provided a vehicle security system for use in a predefined area comprising radio frequency receiving means for receiving a vehicle alarm signal from a subscribing vehicle in the event of attempted vehicle tampering or removal; control means for receiving said signal and communicating to a user as an alarm message; and means for detection of radio frequency signal jamming or attempted jamming, and for providing a jamming alarm signal for communication to a user.
The means for detection of radio frequency signal jamming may comprise one or more noise detectors adapted to detect radio frequency noise at a specified frequency or frequency range and to output a jamming alarm if said detected noise exceeds a predetermined threshold.
The radio frequency receiving means will typically comprise an array of sensors each comprising transceivers, the sensor array being distributed over the predefined area, such as a car park. The sensors may be connected to a control centre which receives the vehicle alarm signals and jamming alarm indications and communicates them to a user and/or to a further remote control centre.
In a preferred embodiment the noise detectors are incorporated into the sensors. Alternatively, the noise detectors may be incorporated into subscribing vehicles, as part of the vehicle transceiver units. In a further alternative arrangement the noise detectors may be dedicated noise detection units separate from said sensors or vehicles, in radio frequency communication with said sensors. With the latter two arrangements the noise detectors may be adapted to detect an increasing noise signal, and to output a jamming indication as a radio frequency signal at a higher amplitude than said detected noise.
The noise detectors may be arranged to output a jamming alarm signal on detection of an excessive noise condition only after a predetermined time, in order to avoid false jamming alarms possibly caused by transmitory radio frequency noise from stray devices or machinery, such as generators or the like.
In an alternative passive noise detection technique the means for detecting of radio frequency jamming comprise at least one radio frequency transmitter adapted to send test messages to a radio frequency receiver, a jamming indication signal being generated in the absence of receipt of said test message. The system preferably requires an array of sensors provided distributed over said predefined area, said sensors comprising transceivers which constitute each of said vehicle alarm receiving means and said radio frequency receivers of said jamming detection means, and said radio frequency transmitters, said sensors being adapted to periodically send test messages to other sensors, the system generating a jamming indication in the event of the absence of receipt of said test messages.
Alternatively, an array of monitoring devices including further transceivers are provided, wherein the sensors are adapted to send test signals to said monitoring devices which on receipt in turn send acknowledge signals back to the transceivers of said sensors, the system generating a jamming indication in the event of the absence of an acknowledge signal.
In a further alternative, the sensor array has transceivers which constitute said vehicle alarm receiving means and said radio frequency transmitters, wherein the sensors are adapted to send test messages to in-vehicle transceivers which in response to such test messages return acknowledge signals to the sensors, the system generating a jamming indication in the event of the absence of an acknowledge signal.
In a still further alternative the sensor array comprises transceivers which constitute said vehicle alarm receiving means and said radio frequency transmitters, wherein the sensors are further adapted to receive test signals sent from in-vehicle transceivers, and in response to generate and transmit acknowledge signals to in-vehicle transceivers, the absence of an acknowledge signal to said in-vehicle transceiver generating a jamming indication signal.
The latter two alternatives require that the sensors are further adapted to receive signals from vehicles which are leaving the predefined area, the system preventing the absence of acknowledge signals from such vehicles from triggering jamming indications.
The sensors are preferably connected to a local control centre which includes a database of data relating to subscribing vehicles and their owners, which may in turn be further connected to a remote centre possibly linked to several predefined areas such as car parks or the like.
The system may further comprise exit restraint means for securing on request said area exit points against vehicle exit, and processing means for processing vehicle alarm signals from a subscribing vehicle within said area and outputting command signals to said exit restraints. These may be in the form of movable barriers, grilles or wheel traps.
In-vehicle sensing means may be provided to sense tampering with the vehicle or unauthorized operation, and outputting the alarm signal, such as a door sensor, hood sensor, ignition sensor, and vehicle interior movement sensor. Vehicle immobilising means may comprise one or more of a starter motor cut-out, fuel pump cut-out, fuel line cut-out and electrical fuse burn.
An embodiment of the present invention is now described, by way of example only, with reference to the following drawings in which:
Turning to the drawings,
Although the system finds particular applicability for the security of land vehicles such as cars, trucks etc, as indicated 4 in
In outline, the vehicle 4 includes one or more in-vehicle security devices, as discussed further below. The in-vehicle security devices communicate with an on-site security control system 8, preferably through a radio frequency link. This on-site system 8 includes communications hardware such as an array of suitably positioned monitoring sensors 9 each including a transceiver 10 connected to a control system including a local management centre 12. The management centre 12 can provide or control a variety of alerts and/or disabling actions, such as alerting security personnel and/or the vehicle owner or user of the attack on the vehicle, activating in-vehicle immobilizing devices, activating exit restraints 14 at the exit for the car park such as closable gates, barriers or extendable wheel traps. The management centre 12 may also communicate with one or more remote centres 16, which may be control centres of the same or a related commercial undertaking or other types of entities such as the police or other emergency services.
The in-vehicle system is described in more detail with reference to
In an “alarm” condition the alarm sub-system 20 activates the transceiver sub-system 22. This comprises a control microprocessor 32, oscillator 34 providing clocking control, a radio frequency transmitter 36, and radio frequency receiver 38. A noise detector 39 is provided for detection of excessive noise, such as might be associated with an attempt to jam the system, as will be discussed further below. A single antenna 40 is illustrated with a switch allowing controlled selection, depending on a transmission or reception status, but equally individual antennae could be provided for each. A power supply/regulation circuit 42 provides system power from the main vehicle battery, at typically 12V or 24V, with a back-up (and generally concealed) battery 43 also provided, as is conventional for vehicle security systems to prevent system failure in the event of tampering or disconnection of the main battery.
The alarm sub-system 20 and transceiver sub-system 22 may also be connected to a vehicle immobilization sub-system 24. A variety of vehicle immobilization techniques may be utilized, including but not limited to:
As discussed above the car park or other securable area generally indicated 6 in
Ideally, the frequency of communication is one which is reserved for the operator of the service as this affords increased security. Typically, the frequency is in the VHF (very high frequency) or UHF bands (ultra high frequency). VHF is ideal for short distance communication, being relatively free of inference from electrical equipment. Typically, operation in the range 30 MHz to 300 MHz (wavelength 10 m to 1 m) is employed. UHF frequencies generally similar to those used in mobile communications in GSM, CDMA and 802.11 implementations can also be used, with the advantage that there are many proprietary antenna designs particularly appropriate for deployment in confined areas.
The array of sensors 9 is connected to an on-site control centre 12 which includes a computer 50 or other processing means, interconnected through a network interface 145, within each sensor and through a local area network (LAN), of wired or wireless type. The control centre 12 may be dedicated to the security system 2 or may be integrated with a control or management system of the car park operator or building management. Typically, the control centre 12 is staffed by personnel who, when an alert is received, may investigate the attack or take other action as appropriate. The computer 50 may store details of subscribing vehicles 4, such as vehicle type, registration number, owner details and contact details, and in the case of car parks where particular vehicles have allocated parking spaces, the location of the parking space all in a local database, indicated 52.
As an alternative or in addition to the local management centre 12, a remote control centre 16 may be in communication with the LAN either by dedicated line or via the Internet or other suitable connection. For example, a wireless communication might be used where the transceivers 10 include an antenna typically of higher power than those for the on-site communication. The remote control centre 16 might usefully provide control of a number of on-site control centres, including a database 54 of subscriber details which is regularly synchronized with individual on-site databases 52.
The local management centre 12 (or indeed remote management centre) may be connected to one or more security devices within the car park, such as exit restraints generally indicated 14 in the form of closable gates or barriers or grilles, or wheel traps. These may be operated automatically on an alert being received, or activated manually by security personnel at the management centre.
The operation of the system 2 in response to an attack on a vehicle is now described, predominantly with reference to
The alert message is received by one or more nearby system sensors 9 which relay it via the LAN to the control centre 12. The vehicle identity as identified by the alert message is matched with stored information about the vehicle and its owner, and an incident report generated containing information such as date and time of alert, vehicle make, model and colour, registration number, usual parking location, and the reporting transceiver location.
This incident report is displayed to the user, typically security personnel within the control centre 12, but may also be sent to the vehicle owner. The same alert message is repeatedly sent from the vehicle every “t” seconds, received by the sensor(s) 9, and forwarded via the LAN to the control centre 12, and if any change since the previous report then updating the incident report.
On receipt of the incident report, if appropriate the user is able to dispatch security personnel to investigate. The user is also able to initiate an action within the vehicle (indicated “action 1” in
The system 2 is able to perform internal checks of sensors. To this end the control centre 12 generates every “v” seconds “check sensor” messages to the complete set of transceivers, which generate “status OK” replies in response. The absence of such a reply indicates to the user that a sensor is not functioning correctly and must be repaired or that jamming may be taking place as further described below.
A particularly important feature of the system is the provision of means to detect attempts to jam the system. It is relatively easy for those of malicious intent to obtain devices which prevent, within a localized area, the operation of radio frequency communications. Typically, such devices emit white noise at a particular or spread of frequencies, thereby drowning out communications at that frequency.
In an active jamming detection system, the sensor array 9 and/or the in-vehicle transceiver 22 can be adapted so that each sensor or transceiver incorporates a noise detection circuit, including an appropriate filter to remove irrelevant frequencies, and logic control whereby the detected noise level at a specified frequency or range of frequencies (being at or about the frequency of communication of the security system, ie the transceiver-sensor communication) is compared in a comparator to a specified noise value, and if exceeding that value, sending a signal to the control system indicative of a possible jam condition.
As an alternative, dedicated noise detectors separate from the sensor array 9 could be distributed throughout the securable area 6 and connected in a wired or wireless manner to the LAN.
As a further alternative, dedicated noise detectors separate from the sensor array 9 could be distributed throughout the securable area 6, and in radio frequency communication with the sensor array. In this case, since the communication is possibly interrupted by a jamming signal, the noise detector would include appropriate control or logic to monitor an increasing noise signal and to transmit a jamming detected signal prior to communication loss, preferably at a stronger signal strength for a short duration.
As an alternative to the use of an “active” jamming detection using noise detection, various passive jamming detection systems are possible, in which instead of actively triggering a jamming indication on noise detection, the breakdown of radio frequency communication of system components is used as an indication of a possible jamming event.
Such signal may be triggered internally, for example by detection of start-up of the vehicle engine, or through detection of the vehicle passing an exit point in the securable area 6. Thus, depending on the precise details the “leaving network” signal may be detected by the sensor A, or at a different sensor, such as sensor B as indicated in
