GB2402529A

GB2402529A - Security System for control of zone access

Info

Publication number: GB2402529A
Application number: GB0312719A
Authority: GB
Inventors: Neal Andrew Radford; Stefanie Anne Radford
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-06-03
Filing date: 2003-06-03
Publication date: 2004-12-08
Also published as: GB0312719D0

Abstract

A number of controlled zones A-C are monitored by respective PIR detectors 10 which are connected to a central processing unit 12 to generate an alarm condition if movement is detected in any of the monitored zones. Each of the zones is also monitored by a proximity sensor 20 which is responsive to encoded short-range radio signals emitted by pass units 22 carried by authorised people such as to inhibit the generation of an alarm condition when an authorised person enters a permitted zone. The system can be programmed to give individuals free access to selected zones, but generating an alarm condition if they enter an unauthorised zone.

Description

SECURITY SYSTEM

TECHNICAL FIELD OF THE INVENTION

This invention relates to security systems which are used for access control.

BACKGROUND

Controlling access to premises without inconveniencing legitimate users can be a major problem. In many commercial premises it is desirable that authorised personnel should be able to move freely from area to area without having to use keys or enter access codes. Such security measures also pose major problems for people with sight problems or physical disabilities. In many cases different areas may have different levels of security. For example, reception areas may be freely accessible to anyone.

Other low security areas may be freely accessible to staff and visitors with legitimate reasons for entry, whilst other areas may require a high security status, only being accessible to a limited number of authorised people.

Door-based access control systems are quite common, but apart from inhibiting the free movement of legitimate users, system security is also wholly reliant on people keeping the doors closed. It is relatively easy for someone to wait until an authorised person passes through the door and then slip in before the door closes. Also, there is a strong temptation for people to wedge the doors open, to provide better ventilation in hot weather

for example.

In a domestic situation, although intruder alarm systems may be installed they provide little protection when disarmed. Many people do not bother to arm the system every time they go out. Furthermore, crime statistics show that many burglaries take place while the premises are actually occupied, and even diligent users normally disarm the alarm system when they are at home.

The present invention seeks to provide a new and inventive form of security system which causes minimum inconvenience to legitimate users whilst at the same time providing an increased level of security against unauthorized access.

SUMMARY OF THE INVENTION

The present invention provides a security system in which a plurality of zones are monitored by respective movement detectors which are arranged to generate an alarm condition if movement is detected in any of the monitored zones, and each of the zones is also monitored by a proximity sensor which is responsive to signals emitted by pass units carried by authorised people to inhibit the generation of an alarm condition when an authorised person enters the zone.

BRIEF DESCRIPTION OF THE DRAWINGS

The following description and the accompanying drawings referred to therein are included by way of non-limiting example in order to illustrate how the invention may be put into practice. In the drawings: Figure 1 is a schematic diagram of a security system in accordance with the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

The security system is installed to control access to a number of mutually distinct zones represented in this example by the three zones A- C. The zones may be areas of a building such as a factory, shop or office, but they could equally be areas of a domestic premises. Each of the zones is monitored by one or more passive infra red (PIR) movement detectors 10 which are all wired to a programmable controller 12. Other forms of movement detector could be used, e.g. ultrasonic. As in a conventional intruder alarm system, if any of the sensors 10 detects movement of a warm body within its monitored zone it signals the controller 12 which may respond by generating an alarm signal to activate a suitable alarm system. This could include one or more audible and/or visual alarm units 14 located in any convenient position, either in the vicinity of the system or remotely. An alarm can also be raised remotely via a telephone network or pager system

for example.

Each of the zones A-C is also provided with at least one proximity sensor 20.

These may be located in any convenient position within the monitored zone, although it will often be most effective to install one adjacent to each or the doorways through which the zone may be entered. For ease of installation the proximity sensors 20 could also be built into the same housing as the PIR detectors if desired. People P who are authorised to enter the controlled zones are each given a pass unit 22 incorporating a small transmitter, which may take the form of a badge, card, key fob etc. The transmitter may operate on VHF or UHF with low power, sufficient to give a maximum range of approximately 15 metros. Whenever a person with one of the pass units enters one of the zones A-C the detector 20 picks up localised signals from pass unit 22 and signals the controller 12 to indicate that an authorised person is present. This inhibits the generation of an alarm condition so that the person can move freely throughout the controlled areas without generating an alarm. When they leave the controlled zone this too is sensed by the detector 20 and signalled to the controller 12.

Should someone without a pass unit enter a controlled zone, as indicated by the person X, the PIR sensor 10 will signal their presence to the controller 12 as before, but since this is not accompanied by an inhibit signal from the corresponding proximity sensor 20 an alarm will be generated.

The system can remain operational for 24 hours of the day if desired. Thus, in a domestic installation for example, it is not necessary for the alarm to be disarmed when the premises are occupied.

It should also be noted that people without a transmitter unit 22 can still move throughout the zones if they are closely accompanied by an authorised person with a suitable transmitter. No alarm will be raised unless they stray off on their own, thereby presenting an increased security risk.

In a basic form of the security system, which may be used in domestic premises for example, the detectors 20 can simply respond to radio signals which are sent out by the pass units on an allocated VHF or UHF frequency.

Zone control may be achieved by arranging the detectors to respond to different signal or modulation frequencies so that people with an appropriate transmitter unit may freely enter certain zones whilst generating an alarm if they should enter non-permitted areas.

A preferred form of the system which is capable of providing a higher level of security can use pass units which send out encoded identification signals, e.g. a twelve digit code. The proximity sensors 20 are designed to receive the coded signals and either decode them or pass the signals to the central control unit 12 for decoding. The central controller 12 then has sufficient information to determine whether the carrier of a particular pass unit is allowed in a particular zone and react accordingly. Again, all authorised people could be provided with units having the same security code allowing them equal access to all zones, but the system also allows people with different levels of security clearance to be provided with different codes giving each group access to certain controlled areas.

Another possibility is for each individual to be provided with a unique identity code. This allows the controller to be reprogrammed at will to control the areas to which each person has access. The allocation of distinctive codes to different pass units also allows the controller to incorporate a data logging facility to record the movements of different people over a period of time.

The central processing unit 12 can be programmed to react in other ways.

For example, if a person having clearance to enter certain areas enters a room they do not have access to a localised alarm could be activated or a text message sent to the site security personnel. In another version of he system, if a person enters a room with clearance various tasks could be performed by the central processing unit such as adjusting light levels, stopping or starting various pieces of machinery, adjusting the heating levels and so on.

The pass units could transmit additional data to the controller 12 via the proximity sensors 20. Thus, for example, the transmitter units could signal an error or low battery condition. A message can then be passed back to the individual advising them that their unit requires attention before an alarm condition occurs. In another development of the system, the detectors 20 and pass units 22 can use two-way communication allowing the bi- directional exchange of data between the individual units and the central controller. The pass units could, for example, enter a quiescent power- saving mode until interrogated by a proximity sensor 20, whereupon they transmit the necessary identification data.

Such a system is particularly useful for blind, partially sighted or disabled people who may have difficulty in operating conventional access controls.

It will be appreciated that the features disclosed herein may be present in any feasible combination. Whilst the above description lays emphasis on those areas which, in combination, are believed to be new, protection is claimed for any inventive combination of the features disclosed herein.

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Claims

1. A security system in which a plurality of zones are monitored by respective movement detectors which are arranged to generate an alarm condition if movement is detected in any of the monitored zones, and each of the zones is also monitored by a proximity sensor which is responsive to signals emitted by pass units carried by authorised people to inhibit the generation of an alarm condition when an authorised person enters the zone.

2. A security system according to Claim 1, in which the movement detectors are passive infra red sensors.

3. A security system according to Claim 1 or 2, in which the pass units incorporate a low power radio frequency transmitter.

4. A security system according to any preceding claim, in which the system is arranged to distinguish between signals sent out by different pass units.

5. A security system according to any preceding claim, in which the system is capable of restricting the zones to which each pass unit has access, allowing access to some of the zones whilst generating an alarm condition if a non-authorised zone is entered.

6. A security system according to any preceding claim, in which the pass units transmit an identification code which is received by the proximity sensors for use in determining whether the person with the pass unit is authorised to enter a particular zone.

7. A security system according to Claim 6, in which the proximity sensors interrogate the pass units to obtain the identification code.

8. A security system according to any preceding claim, in which the movement detectors and proximity sensors are connected to a common programmable processing unit.

9. A security system according to Claim 8, in which the processing unit incorporates a data logging facility to record the movements of the pass units within the controlled zones.

10. A security system according to Claim 8 or 9, in which the processing unit is arranged to control environmental conditions within each zone.

11. A security system substantially as described with reference to the drawing.

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