VEHICLE SECURITY SYSTEM

Abstract: A vehicle alarm comprises a control unit (2) coupled to an R.F. receiver (4) for receiving a deadlock signal from a remote transmitter (6). When the signal is received, a vehicle to which the alarm is fitted is locked and an ultrasonic movement sensor (8) is activated. The sensor (8) is allowed to stabilise for a predetermined delay period. If after a further predetermined time, no movement has been detected, the vehicle is deadlocked. The alarm minimises the risk of someone being deadlocked in the vehicle.

Description: VEHICLE SECURITY SYSTEM This invention relates to a vehicle security system having a movement sensor and a deadlocking system for the doors of the vehicle. Movement sensors of the "volumetric" type are non- contact sensors which are used in security systems to monitor for and detect movement within the interior of vehicles, either in the passenger compartment or luggage compartment. Such sensors can detect unauthorised entry into the vehicle and operate the security system accordingly. They can also be used to detect whether a person or animal is inside the vehicle since such a person or animal will usually move by a detectable amount within the period of time over which a check is made. In order to improve vehicle security, it has become common to equip a vehicle with a deadlock feature whereby it is possible to lock the vehicle doors and then to disable the operation of the interior lock control on each door. With those controls disabled, it is possible to open the vehicle only by using a key in an external lock. Thus an intruder cannot open a vehicle door by breaking a window and unlocking a door from inside the vehicle. It is known to associate the deadlock feature with a vehicle immobilisation and alarm system such that the action of setting the alarm and immobilising the vehicle, perhaps by a remote transmitter, can also be made to deadlock the doors. This has the advantage that the driver gets into the habit of deadlocking the doors every time the vehicle is left. However, it is not unknown accidentally to lock the vehicle with someone inside. If deadlocking is enabled, the person locked inside the vehicle will be unable to let themselves out. Accordingly the present invention provides a vehicle security system comprising detection means for detecting the presence of a person in the vehicle, locking means for at least one door of the vehicle, deadlocking means for preventing unlocking of the locking means from inside the vehicle, control means for operating the deadlocking means, a receiver for receiving a deadlock signal, wherein the control means is arranged, on receipt of the deadlock signal, to monitor the output of the detection means for a predetermined time to check for the presence of a person in the vehicle and only if no person is detected, operate the deadlock feature to deadlock the vehicle. The present invention also provides method of operating a security system of a vehicle, the system including detection means for detecting the presence of a person in the vehicle, and means for activating a deadlock feature of a vehicle, the method comprising the steps of receiving a deadlock signal, monitoring the output of the detection means for a predetermined time to check for the presence of a person in the vehicle and only if no person is detected, causing the deadlock feature to be activated. By using the detection means to detect the presence of a person in the vehicle prior to deadlocking it, the possibility of deadlocking someone in the vehicle is minimised. Preferably the detection means comprises movement detection means which detects the presence of a person in the vehicle by detecting movement of the person. Preferably, if a person is detected during the predetermined time, then an alarm is raised to draw the attention of the driver to the problem and to warn him that the vehicle is not deadlocked. Preferably the monitoring of the detection means output is delayed for a predetermined delay period to allow the movement sensor output to stabilise. This is particularly important when using an ultrasonic movement sensor, for example of the type disclosed in earlier International Patent Application No. WO/GB93/19385, since such a sensor can be affected by air movement. The delay period allows time for the air in the vehicle to settle. Preferably also, the detection means is not activated or its output is ignored if any of the doors, windows, tailgate, sunroof or the like, which can be collectively referred to as wings, are open. In the case of an electric window and/or sunroof, these may be shut automatically upon receipt of the deadlock signal. Advantageously, the vehicle doors may be caused to lock (but not to deadlock) immediately the deadlock signal is received. The invention will now be described by way of example with reference to the accompanying drawings of which: Figure 1 is a side view of a vehicle including a security system according to the invention, and Figure 2 is a schematic block diagram of the system of Figure 1. With reference to the drawings, a vehicle 1 has a security control unit 2 coupled to an R.F. receiver 4. The control unit 2 controls the door locks 3 of the vehicle and can cause them to lock and unlock, and also to engage or release a "deadlock" within the lock mechanism which prevents unlocking of the doors by use of the sill buttons 5. The receiver 4 is arranged to receive a "deadlock" signal from a remote R.F. transmitter 6. The transmitter 6 is of the type housed in a key fob. Also coupled to the control unit 2 is an ultrasonic movement sensor 8 for detecting movement at almost any point inside the passenger compartment 9a or luggage compartment 9b of the vehicle 1. It does this by checking for a Doppler shift in reflected ultrasound signals from various areas within the passenger compartment and luggage compartment. An audible alarm siren 10 is also connected to the control unit 2 and can be operated by it. Front and rear door sensors 12, 14 are provided in the form of switches which detect whether the front and rear doors are open or closed. Similar sensors 16, 18 are provided for the tailgate 20 and sunroof 22 respectively. The system is adapted to try to minimise the possibility of deadlocking someone in the vehicle by inhibiting the deadlock feature of the vehicle if movement is sensed inside the vehicle. In operation, once a deadlock signal which indicates that the vehicle should be deadlocked is received by the receiver 4, the vehicle doors are immediately locked. Five seconds later (to allow time for air in the vehicle to settle) , the control unit 2 checks the door, sunroof and tailgate sensors 12, 14, 16, 18 to ensure that the doors, sunroof, tailgate and windows are shut. If they are, the control unit 2 then activates the movement sensor 8 for ten seconds. If no movement is sensed in this ten second period, the doors are deadlocked. If movement is detected in the ten second period this is taken as an indication that there may be a person 24 or animal inside the vehicle. The vehicle is therefore not deadlocked and an alarm is raised using the vehicle siren 10 as a warning that the vehicle has not been deadlocked and that it should therefore not be left. Although the control means is illustrated schematically in Figure 1 as a single unit, it is in fact laid out as shown in Figure 2. The control means 2 comprises the engine control unit which operates the vehicle immobilisation, and a body electrical control module (BeCM) 2a which has direct links with the sensors 12, 14, 16, 18 of both rear windows, both rear doors, the tailgate and the sunroof, the motors of both rear windows, both rear door locks, and the sunroof, the ultrasonic sensor, the message centre and audible warning (siren) which communicates information to the driver, and the receiver. The BeCM is also linked through a centre console outstation to the window and sunroof operating switches, and through left and right hand side front door outstations to the door lock motors, door sensors, window sensors and window motors of the left and right hand side front doors respectively. It will be appreciated that the present invention would also be applicable to security systems with other means of detecting the presence of a person in the vehicle. An ultrasound system which detected the presence of a person in the driving seat, or any other position in the vehicle, by simply timing a reflected signal from that position could be operated in the same way.

Claims: CLAIMS 1. A vehicle security system comprising detection means for detecting the presence of a person in the vehicle, locking means for at least one door of the vehicle, deadlocking means for preventing unlocking of the locking means from inside the vehicle, control means for operating the deadlocking means, a receiver for receiving a deadlock signal, wherein the control means is arranged, on receipt of the deadlock signal, to monitor the output of the detection means for a predetermined time to check for the presence of a person in the vehicle and only if no person is detected, operate the deadlock feature to deadlock the vehicle. 2. A system according to claim 1 wherein the detection means comprises movement detection means which detects the presence of a person in the vehicle by detecting movement of the person. 3. A system according to claim 1 or claim 2 further comprising alarm means, wherein the control means is arranged to operate the alarm means if the presence of a person is detected within the predetermined time. 4. A system according to any foregoing claim, wherein the control means is arranged to delay the monitoring of the detection means output for a predetermined delay period. 5. A system according to any preceding claim further comprising at least one sensor for sensing whether a wing of the vehicle is open, wherein the control means is arranged not to activate the detection means or to ignore its output if said wing is open. 6. A method of operating a security system of a vehicle, the system including detection means for detecting the presence of a person in the vehicle, and means for activating a deadlock feature of a vehicle, the method comprising the steps of receiving a deadlock signal, monitoring the output of the detection means for a predetermined time to check for the presence of a person in the vehicle and only if no person is detected, causing the deadlock feature to be activated. 7. A method according to claim 6 wherein the detection means comprises movement detection means. 8. A method according to claim 6 or claim 7 further comprising the step of raising an alarm is if the presence of a person is detected within the predetermined time. 9. A method according to any one of claims 6 to 8, wherein the monitoring of the movement sensor output is delayed for a predetermined delay period. 10. A method according to any one of claims 6 to 9, wherein the movement sensor is not activated and/or its output is ignored if a wing of the vehicle is open. 11. A system substantially as hereinbefore described with reference to the accompanying drawings. 12. A method substantially as hereinbefore described with reference to the accompanying drawings.

Inventors: CHARD JONATHON, CHARD, JONATHON
Applicants: CHARD JONATHON, ROVER GROUP, CHARD, JONATHON, ROVER GROUP LIMITED
Application year: 1995
Main classification: B60R25
IPC codes: B60R25, G07C9