GB2298301A - Paging automobile immobiliser - Google Patents

Abstract

A vehicle immobiliser for remotely halting a vehicle is based upon a wide area paging messaging service accessible via the public telephone system. The standard paging code, POCSAG, (Post Office Code Standardisation Advisory Group) is used in conjunction with a user accessible immobiliser code to perform individual functions implemented within the system, the user having access to ten functions and the network-providing company having access to a further thirty functions. The immobiliser is contained within the vehicle not within view of the driver or passengers. All connections are made to the immobiliser via a multiway plug fit connector wired to the vehicle such that the vehicle is rendered undrivable if the immobiliser is removed.

Description

PAGING AUTOMOBILE IMMOBILISER This invention relates to a remotely activated vehicle immobiliser.

Background.

Automobile immobilisers, although fitted to most makes and models of vehicle have been available for some time to date. They work on a principle of being able to disable operation of the vehicle when not in use by using a key or coding device. This then deters theft and provides protection for the owners vehicle. However whilst being driven the vehicle may not be immobilised.

The idea described here has the ability to disable a vehicle whilst being driven. Its primary purpose could therefore be in the security market. It is not designed for every day use. The main purpose is to slow down and stop a moving vehicle safely, if stolen for example, thereafter immobilising it from further use. This is done remotely from the automobile, over a nationwide coverage range or a smaller zone if required. The method of immobilisation is via the use of a telephone access paging service and a receiver-decoder installed into the vehicle.

The immobiliser is capable of supporting ten user accessible functions. These may be to halt operation of an electronic fuel pump, activate the fuel cut off solenoid on a diesel engine, activate the hazard warning lights, activate central locking, close electric windows etc. In addition to these ten user functions, thirty non-user (network provider) functions are accessible by the network provider only, for test purposes or special actions.

The remote immobiliser is not designed to take the place of a standard immobiliser by providing protection ofa stationary vehicle, although it may be used to perform this function.

Technical Features & Description.

The present invention uses a standard paging receiver to receive paging transmissions from a network provider. The network provided may be any of the large companies offering a message paging service to businesses and the public.

An immobiliser for use within a vehicle and designed to be activated remotely via a wide area paging system. Enabling a moving vehicle to be slowed down and stopped remotely and safely.

Enabling up to ten user and thirty non-user functions to be performed dependent on user's requirements and vehicle's capabilities also via a wide area paging system to be controlled remotely.

The paging receiver is combined with a microprocessor controlled vehicle engine immobiliser all fitted within one box unit. This unit is then fitted within the vehicle in a convenient place out of normal sight of the driver and any passengers. The normal location of the immobiliser would be beneath the bulkhead, dashboard or centre console. This would enable the antenna cable to be located close to the immobiliser, out of driver and passengers site and provide a good signal strength for the immobiliser.

Embodiment of Invention.

Described by way of operation, coding type, example of operation and with reference to the accompanying drawings in which: Figure 1 shows the block diagram ofthe immobiliser system referred to in the text below.

Figure 2 shows the type of code used for the activation ofthe immobiliser.

Figure 3 shows in perspective, a completed example ofthe immobiliser. (Within external case) Figure 4 shows a typical user procedure during the activation ofthe immobiliser in block diagram form.

Method ofOperation.

Due to the exclusive use ofPOCSAG (Post Office Code Standardisation Advisory Group) paging code for wide area paging transmissions the receiving unit is based upon this format ofcode.

Refer to complete system block diagram. Figure 1.

When the paging receiver, block 3, sees its own particular code sent, (POCSAG identification), the receiver recognises the data and will be ready to receive a message.

The complete message it receives is checked for errors and corrected if necessary within the paging receiver. The paging receiver then reformats the received data to the standard ASCtI 7 bit serial data type. This data is then sent to the immobiliser's microcontroller processor, block 2.

The microprocessor checks this data and compares it with its own. Ifthe first eight received bytes match the microcontroller's prestored identification then a function is performed depending on the ninth byte sent to the microcontroller processor. Relays and darlington transistor arrays, block 6, are used thereafter to increase the drive to a level suitable for use in a motor vehicle to switch the ignition, fuel pump, carburettor solenoid, diesel fuel cut offvalve, hazard lights, electric windows etc. The complete system is powered from the unregulated 12 volt negative ground supply of the vehicle. The unit therefore uses internal regulation, block 4, with a rechargeable backup supply source, block 5, should the main line supply fail or be cut. This backup source maintains the status ofthe microcontroller processor during main power failure.The complete system is connected via a multiway plug fit connector, making all connections at once. Connections to the multiway connector are arranged such that removal of the immobiliser renders the vehicle undrivable, whilst the backup supply source maintains the microcontroller's status should it be disconnected for a period, then reconnected.

Coding Type Used.

Figure 2 shows the complete data format sent to the immobiliser via the wide area paging system.

The data sent is as mentioned, standard POCSAG format with a message content that will be reformatted by the paging receiver and sent thereafter to the microcontroller as the immobiliser's identification and function code.

From figure 2 it can be seen that the data sent to the microcontroller consists of eight message data bytes. These data bytes then form an identification code which the microcontroller uses to compare with its own preprogrammed identification. These would normally be numeric characters to enable operation via the use ofa telephone keypad to dial the immobiliser's code.

The last byte is used (by the microcontroller only if the first eight are recognised), to perform a function. (Activate a relay or turn on a darlington driver).

Due to the use therefore ofa telephone keypad by the user to access the immobiliser, only numeric message bytes may be entered. Therefore this constitutes a total of ten functions (0 to 9) which may be accessed by the user. However, with the use of alpha characters, the paging network provider may substitute a numeric function byte for an alpha function character, thereby extending the amount of functions outside the standard user accessible types. These non-user functions may therefore be special test, disabling of immobiliser functions, immediate halt of vehicle (for use by security services) etc.

Only one function however may be performed per each paged message sent to the immobiliser.

The unit so far described is therefore a remotely activated switch using a paging type receiver. The double coding method is used to add protection against error calling by the network service provider to the unit and therefore reduce greatly the chances of accidental immobilisation.

(Estimated accidental immobilisation being no greater than normal vehicle failure whilst driven).

Due to the estimated infrequent activation of the system, an alternative advantage of duel coding means that the network providing company need only use one pager code number for may users, i.e. one code number need only be allocated and will serve up to 99999999 users, each user then having their own message code to access the immobiliser's functions.

On this basis the system is totally expandible and if more users are required then more identification digits may be added by reprogramming the microcontroller to accept more bytes of identification code. Conversely, fewer digits may be allocated to the immobiliser if required to simplify user operation. These modifications would be totally independent of existing users so making any changes more realistic.

Example ofUnit's Action Under Operating Conditions.

The ignition circuit (petrol engine models) is used as the main means ofslowing down the vehicle.

In the case of diesel engines the fuel cut off valve would be used. Description below assumes a petrol engine vehicle.

This is accomplished as follows: On the receipt of the correct message and function codes the immobiliser performs one of two actions dependent on the vehicle's condition at that time.

1. With vehicle not moving or with engine off: The microcontroller activates relays which disables, ignition, fuel pump and carburettor fuel solenoid (Fuel cut off solenoid on diesel engine vehicles). This is done immediately on receipt ofthe relevant message and function codes, ensuring no further movement ofthe vehicle is possible.

2. Whilst vehicle is driven.

To ensure vehicle is halted safely, three different methods are possible during this condition.

a) Accessible by the user via telephone keypad: On receipt of the relevant code and function information the microcontroller will halt the vehicle and activate the hazard lights. Before this is done, however, the microcontroller monitors the speed ofthe vehicle and will only disable the vehicle if it is brought to a halt by the driver. Once halted the ignition, fuel pump and carburettor solenoid are interrupted and hazard lights activated, disallowing the vehicle to be driven any further.

b) Using an alpha function character, only accessible by the network provider: On receipt ofthe relevant alpha function character the system allows the vehicle to be stopped whilst being driven. This is done by interrupting the vehicles ignition system repeatedly at an initial rate of 5 times per second. At this stage the hazard lights are activated. This gives other road users an indication of a fault with the vehicle in question and causes the vehicle to drive poorly. This repeated switching action ofthe ignition system still maintains the vehicles momentum and so is under control of the driver. After a period of 50 seconds (the estimated time to pull over and stop safely), the ignition is interrupted for longer periods whereupon the vehicle will begin to reduce speed and eventually halt and stall the engine.On stalling the engine, the ignition, fuel pump and carburettor solenoid relays are interrupted disallowing the vehicle to be driven any further.

c) Using an alpha function character, only accessible by the network provider: The system is able to halt a vehicle immediately whilst being driven. The ignition system is again interrupted at the rate as in 'b' above but the fuel pump and carburettor solenoid relays are interrupted permanently to halt the vehicle immediately.

Any other functions wired to the immobiliser are available under any conditions but must be accessed separately, one function per page message sent, since the main objective is as described in paragraphs 1 and 2 above, (to disable and halt a moving vehicle).

Test functions are also available and programmed on the immobiliser, (not accessible by user), so that the service network provider may test, reset or discontinue the service provided by the immobiliser. This may be necessary for the network provider, if only to disable operation in the event ofpayments for the service not being made to the provider. This is done by paging the unit in question with its eight byte identification code followed by an alpha character, (these not being normally available on standard telephone keypads for users access).

Claims (15)

1. An immobiliser for use within a vehicle and designed to be activated remotely via a wide area paging system. Enabling a moving vehicle to be slowed down and stopped remotely and safely. Enabling up to ten user accessible and thirty network provider accessible functions to be performed, dependent on users requirements and vehicles capabilities, also via wide area paging system to be controlled remotely.

Four methods of halting the vehicle safely under controlled conditions, depending on the function requested and the vehicles state of movement at the time of information reception by the immobiliser.

Dual coding system used for added safety against accidental system immobilisation.

Alternatively, dual coding used to extend the volume of systems users. (By dual code is meant the standard POCSAG code format followed by a string of ASCII characters, in this case eight plus a function character).

2. An immobiliser as claimed in Claim 1 to remotely slow down and stop a moving vehicle safely by the use offour methods.

3. An immobiliser as claimed in Claim 1 wherein means is provided for up to ten user accessible functions, actions, which may be implemented according to user requirements.

4. An immobiliser as claimed in Claim 1 wherein means is provided for up to thirty non-user functions accessible by the network providing company.

5. An immobiliser as claimed in Claim 1 and Claim 2 to slow down and halt a moving vehicle by interrupting the ignition circuit ofa petrol engine.

6. An immobiliser as claimed in Claim 1 and Claim 2 to slow down and halt a moving vehicle by interpreting the fuel cut offsolenoid of a diesel engine.

7. An immobiliser as claimed in Claim 1 and Claim 2 to halt a vehicle only when the vehicle has been stopped for any reason by the driver. Accessible by the user.

8. An immobiliser as claimed in Claim 1 and Claim 2 to slow down and disable a moving vehicle whilst being driven under controlled conditions by interruption of the vehicle's ignition system, (fuel cut offsolenoid for diesel engine vehicles). Not accessible by the user.

9. An immobiliser as claimed in Claim 1 and Claim 2 to slow down and halt a moving vehicle immediately on receipt of the identification and function codes by interrupting the vehicles ignition circuit, disabling the fuel pump and carburettor solenoid, (fuel cut off solenoid for diesel engine vehicles). Not accessible by the user.

10. An immobiliser as claimed in Claim 1 using a system ofdual coding.

11. An immobiliser as claimed in Claim 1 and Claim 10 using dual coding thereby reducing the risk ofaccidental immobilisation to a level not greater than normal vehicle failure.

12. An immobiliser as claimed in Claim 1 and Claim 10 using dual coding thereby giving a maximum number of immobiliser identification codes whilst using a minimum number of POCSAGaccess codes.

13. An immobiliser as claimed in Claim 1 and Claim 10 where the dual coding system used allows expansion ofthe system without affecting existing users.

14. An immobiliser as claimed in Claim 10 and Claim 13 where the dual coding system used allows further functions to be added to the immobiliser's microcontroller without affecting existing users.

15. An immobiliser as described herein with reference to Figures 1 to 4.