Abstract: A security system is disclosed which is suitable for use in a passive entry and passive starting arrangement for a vehicle 10. A set of transmitters in the form of coils A, B, C are spaced around the vehicle 10, one A, B in each door mirror 20R, 20L and one in a high level brake light 16 at the rear end. Operation of a door handle initiates an access challenge from the vehicle 10 which is sent out successively on a plurality of the coils A, B, C. A portable transponder 26 carried by an authorised user is adapted to pick up the challenge signal and send back to a security controller 18 a response signal in which is included vector information relating to the relative positioning between the vehicle 10 and the transponder 26.

Abstract: A security system is disclosed which is suitable for use in a passive entry and passive starting arrangement for a vehicle 10. A set of transmitters in the form of coils A, B, C are spaced around the vehicle 10, one A, B in each door mirror 20R, 20L and one in a high level brake light 16 at the rear end.

Abstract: A vehicle 10 is disclosed having an automatic child lock function that is controlled by an electronic control unit 4. The electronic control unit 4 receives signals from weight sensors 23a, 23b, 23c in the base portion of each of the passenger seats 22. The findings from the sensors 23a, 23b, 23c are used to determine both the occupancy of the vehicle 10 and to produce a signal indicative of the weight of each of the passengers of the vehicle 10. The electronic control unit 4 is programmed to operate such that if the signal “W” received from a particular sensor 23a, 23b, 23c indicates that the passenger is below a predetermined weight “WC”, which indicates that the passenger is probably a child, the associated door 14, 16, 17 is prevented from being opened from a closed position even when an interior door handle 14b, 16b, 17b is operated by the passenger.

Abstract: A system for effecting closure of one or more vehicle windows 30 comprises a portable transmitter unit 14 and a body control unit 12 which can communicate via an alternating magnetic field produced and detected by a pair of conducting coils 16a, 16b, and via a radio frequency transmitter 24 and receiver 22. On transmission of a R.F. closure request signal from the transmitter unit 14, a confirmation request signal is sent by the body control unit 12 via the magnetic link. The confirmation request signal is repeated during closure of the window. The transmission unit responds to each confirmation request signal by transmitting a R.F. confirmation signal, receipt of which enables raising of the window to be initiated or continued. Closure of the window is only initiated if the transmitter unit 14 is within the relatively short range of the magnetic link, and only continues while it remains within range.

Abstract: A vehicle security system comprises a transmitter 18 for transmitting coded signals, a receiver 16 for receiving the coded signals, and a control unit 14 for operating an engine immobilization system 12 in response to receipt by the receiver 16 of a valid coded signal. The transmitter 18 is arranged to transmit the coded signal as a sequence of pulses of electromagnetic radiation which are amplitude modulated at a modulating frequency, and the receiver includes an audio frequency filter arranged to pass signals having a frequency within a range including said modulating frequency. This allows the filtering out of high powered interfering signals which are of the same radio frequency as used in the system, but which are not modulated at the same audio frequency.

Abstract: The security system comprises a coil (34) close to the vehicle ignition lock (38), a control unit (10) for energizing the coil and a transponder which comprises a coil (32), a transistor (30) and a transmitter (24) and a power supply (26). In use the coil (32) picks up a conventional alternating magnetic signal emitted by the coil (34), and provides sufficient power to activate the transistor (30) which connects the power supply (26) to the transmitter (24) causing it to transmit an enabling signal to the control unit. The control unit may be programmed to re-mobilize the vehicle engine on receiving of the correct signal.