WO1982000377A1

WO1982000377A1 - A location device

Info

Publication number: WO1982000377A1
Application number: PCT/GB1981/000142
Authority: WO
Inventors: Security Systems Ltd Mastiff
Original assignee: Taylor D
Priority date: 1980-07-21
Filing date: 1981-07-15
Publication date: 1982-02-04
Also published as: EP0056045A1; IT8148930A0; IT1142855B; BE889687A; JPS57501253A

Abstract

This is a location device for tracing the movement of people in a building. Doorways (40) or passages (10) constituting entrances to a building or means for moving from room to room in a building have location devices consisting of two pick-up loops (12), (14) which have to be passed in turn by someone moving through the doorway, and a register unit (28) is sensitive to the order in which the loops receive signals from pocket radio transmitters carried by the persons with characteristic transmission patterns enabling the different tokens to be identified by the register unit. There can be a display and a record of the movement of every person with his token into and out of the area, and between rooms in the area. The pick-ups can be associated with lamp and photocell arrangements (16, 18) which will be broken by anyone moving along the passageway, so that an alarm can be given if a light beam is broken and a signal from the token is not being picked up showing that the person is an intruder.

Description

A LOCATION DEVICE

The present invention relates to a location device for example, for locating people in a building and recording their movement into and out of the building, and from room to room. According to the present invention, a location device comprises at each of two spaced positions which have to be passed in turn by a person or object, a sensor of a body passing that position, the two sensors being connected to a register unit capable of recording in what order the sensors are operated.

The use of two spaced sensors enables the movement of a person to be detected and also his direction of movement in or out by noting the order in which the sensors sense his presence. Preferably, each sensor comprises a pick-up of radio or inductive signals from a token carried by the person in his pocket to leave his hands free.

Preferably, a further pair of sensors are provided one at each spaced location, which automatically generates an alarm signal if it is actuated, the alarm signal being connected to the register.

The alarm signal from one of these further sensors can be nullified if the pick-up in that location is receiving an appropriate signal from a token. This allows the system not only to record movements of people, but also to give. an alarm if someone not carrying a token passes through.an entrance.

The further pair of sensors can be each a lamp and photo-cell arrangement with a light beam which is interrupted by anyone going through the entrance. Advantageously, there is an alarm and display unit which indicates in which direction a person has passed through the location device, and indicates if an unauthorised person has passed through. Different tokens may generate different characteristic signals, both of which nullify the alarm signal, so that the location of each token, and thus each member of personnel, may be known at the alarm display unit.

The location device is particularly suited to locating personnel within an area which may have several entrances, each of which is equipped with the location device. Preferably the register unit for ail of the location devices is able to count the number of people located by each device.

The display and control unit is then able to show the number of people in a particular area, as well as who they are. A number of rooms may be fitted with a location device at each antrance, and different rooms may require different characteristic signals from tokens to nullify the alarm signal. In this way different levels of security can be achieved.

The control unit may be associated with a computer and a timer and the computer can be programmed to give alarms or other indications if certain rules are broken, for example rules saying that someone must not be in a particular area for longer than a certain time, or that someone of one security level must not be in a particular area unless accompanied by someone of a higher security level, or. saying that all the people of one security level must not be in one area together.

In a very convenient method of coding tokens with characteristic transmissions identifying particular tokens or groups of tokens, all the tokens transmit signals at the same carrier frequency, and in the form of bursts of carrier frequency pulses, separated by break pulses consisting .of an absence of carrier frequency, the different characteristics of different tokens being in a number of carrier frequency pulses in a burst.

That method of coding tokens is the subject of British Patent Specification No. 1528901, but according to another aspect of the present invention, that system can be improved by having the duration of the break pulses for all the tokens the same.

According to a further aspect of the present invention, each of the tokens on such a system is arranged to produce its pattern of bursts of carrier frequency cycles, and break pulses for short intervals, for example, with a length of a few milliseconds separated by much longer intervals of no transmission, for example of up to one second in duration, so that two tokens can be close together and the signals from them picked up without much danger of interference between signals from the two tokens. That enables the difference between the numbers of carrier frequency cycles in bursts for two tokens to.be quite small, perhaps as small as 16 cycles.

The invention may be carried into practice in various ways, and one embodiment will now be described by way of example, and with reference to the accompanying drawings; in which:- FIGURE 1 is a diagram of an entrance to a building or room provided with a location device; and

FIGURE 2 is a diagram of a building incorporating a number of entrances and location devices as shown in FIGURE 1. The location device may be installed at any location where a person has to pass in entering or leaving the building or moving from one room to another and FIGURE 2 shows it installed in a doorway or short corridor 10. Two sensors in the form of pick-up loops 12 and 14 are fitted below the floor of the corridor 10, one in front of the other. Each pick-up is associated with a light and photocell arrangement 16 or IS which is arranged so that a beam from a lamp to a photocell will be interrupted by a person passing the pick-up.

Each pick-up 12 or 14 will pick up radio signals from a person passing over it.Signals picked-up at 12 and/or 14 are passed through respective amplifiers 20, 22 and identifying units 24, 26 to a recording unit 28 which is connected to an alarm and display unit 30. Each person carries a pocket token embodying a generator or reflector of coded radio signals for pick-up at 12 and 14 even while in the person's pocket. When either of the light beams at 16 and 18 is interrupted, a signal is sent to one of a pair of control units 32 and 34 which are respectively connected to the identifying units 24 and 26. A person carrying a token who walks along the corridor 10 in the direction of the arrow 36 first passes over loop 12. The loop picks up the signal from the transmitter and passes it through the amplifier 20 to the identifying unit 24. Each transmitter has a characteristic code which the identifying unit interprets to pass a suitable signal to the recording unit 28, which in turn passes the information onto the alarm and display unit 30.

As the person continues in the direction of the arrow 36, the light beam at 16 is interrupted and a signal is passed through the control unit 32 to the identifying unit 24. This signal will automatically cause an alarm signal to be sent through the recording unit 23 to the alarm and display unit 30 unless the identification unit 24 is receiving a signal from 20 indicating that the person is carrying a token with an appropriate code indicating that the holder is authorised to pass along the corridor. If such a signal is received at 20, the alarm signal is nullified. As the person travels further along the corridor he passes over tne second picκ-up 14 and. through the light beam at 18 where the same operation is carried out as described above for the pick-up 12 and the light beam at 16. The two pick-ups 12 and 14 in series allow the recorder to determine, in dependence upon the order in which signals are received, in which direction a person is travelling through the corridor. The same effect could be achieved by the two light beam arrangements 16 and 18, or even with one pick-up loop and one beam arrangement if they are spaced along the corridor and there is a delay after the beam is interrupted to give time for a radio signal to be picked up, and means for holding a picked up radio signal until the beam is interrupted.

The location device can also identify which transmitter has passed over the security system or indeed whether the person is carrying no token, or a wrong token and to record and display this information. The system is particularly well suited to a building having a number of rooms, where it is desired to know how many people are. in the building, and in which particular room each person is, and whether any unauthorised persons have passed into the building or from one room to another.

FIGURE 2 shows a building 38 incorporating a number of location devices 11, one in each doorway 40.

The building 38 comprises a reception area 44, which houses the alarm and display unit 30 and a secured area including a number of rooms 46. Each doorway 40, including the doorways which connect adjacent rooms 46, is fitted with a location device 11, generally as described with reference to FIGURE 1. Each device 11 is connected to the alarm and display unit 30. The units 20,22,24,26,28,32 and 34 can be mounted adjacent the doorway as shown at 38.

The unit 30 is able to give information about how many people have entered and left the secured area, how many people are in each room, and, if each person is carrying a transmitter with an individual characteristic code, in exactly which room each person is. The unit 30 is also able to show if any person passes through a doorway without a token or with a wrong token, and his movement throughout the secured area may be followed.

Some rooms in. th.e building may be restricted for use by a limited number of people, and thus, while all people with transmitters may be able to move about freely in two of the rooms, only a limited number may be allowed into the third room without giving an alarm.

In a typical case each of the loops 12 and 14 is about one foot long in the direction of the arrow 36, and as wide as the passageway 10 with perhaps two or three feet spacing between the loops. The light beam arrangements, 16 and 18 are positioned over the centres of the respective loops.

The tokens may be as described in British Patent Specification No. 1414119 with the different tokens or different groups of tokens transmitting oscillations at different frequencies. Alternatively the tokens may be as described in British Patent Specification No. 1528901, all operating on the same carrier frequency with the different codings between tokens or groups of tokens consisting of the number of carrier- frequency cycles in a burst of transmission separated by a "break" pulse with no transmission. The duration of the break pulses will be the same for all tokens.

In one example all the tokens transmit at a common carrier frequency of xKc/s and each transmits a burst of carrier frequencies cycles, then a break pulse with no transmission, then another burst of the same number of carrier frequency cycles, and then another break pulse, and so on. The break pulses are the same for all the tokens and in one example are for a duration of 256 carrier. frequency cycles. The bursts of pulses for different tokens or groups of tokens are separated by 16 carrier frequency pulses so that one set of tokens may have 1,000 carrier frequency cycles in each burst, while tokens in another group may have 1016 carrier frequency cycles in each burst, and other tokens may have bursts of 1032 carrierfrequency cycles.

Each token can be arranged to operate in a " spitting" mode, according to which It generates its characteristic pattern for a random spell lasting a few milliseconds after which it does not transmit for a period of say up to one second. If the varrier frequency is high enough, the characteristic signal can be detected by the unit 30 if there are perhaps 10 bursts of pulses and break pulses in the few milliseconds period. However it is unlikely that two tokens will be "spitting" at the same time, and even less likely that two tokens carried by different people passing through the same passage will be "spitting" at the same time, so that the likelihood is that each individual will be able to be identified by the system, even though two or three people are passing through the passageway almost together. The advantage is more important if a large area is being protected. There is a delay in the pick-up responding to transmissions from a token which is further from the pick-up loop than another token, although perhaps orientated for its transmitted signals to be of sufficient strength at the loop to be picked-up. In such a case the detector would apparantly see a longer break pulse than the actual break pulse of the transmitter but since all the break pulses of all the transmitters are in the example given 256 carrier frequency cycles long, the detector will recognise that some of the pulses at the start of a new transmission burst have been lost due to the range of the transmitter, and the detector can replace those pulses so that correct identification can be made The detector may be associated with a computer which can be programmed to give a warning if any of a number of different όccurences arises.

For example, there may be a timer which gives a warning if an individual has been in a particular area for greater than a preset time. It may be arranged that a warning is given if an individual at one security level is in an area unaccompanied by an individual at a different security level. Again it may be arranged that a warning can be given if all people of a particular security level are in one area together.

In general the display unit can show where every token is, and can show how long they have been in those positions, and can give warnings if any of a number of preset rules have been broken.

Claims

1. A location device comprising at each of two spaced positions which have to be passed in turn by a person or object, a sensor of a body passing that position, the two sensors being connected to a register unit capable of recording in what order the sensors are operated.

2. A device as claimed in Claim 1 in which each sensor comprises an Inductive pick-up loop or other device.

3. A device as claimed in either of the preceding claims in which each sensor comprises a light and photocell arrangement in which a beam of light leading to a photocell is broken by a body passingthe position.

4. A device as claimed in any of the preceding claims with the two sensors are positioned in a door-way or passage-way one in front of the other.

5. A device as claimed in any of the preceding claims in combination with a number of tokens capable of radiating radio or inductive signals, in which the register unit is capable of distinguishing between signals picked up from different tokens.

6. A device as claimed in any of the preceding claims including an alarm which is arranged to be given if a body is detected at a position, and appropriate signals are not being picked up.

7. A device as claimed in any of the preceding claims including a timer capable of recording time intervals between operations of the device.

8. A device as claimed in any of the preceding claims including a visual display derived from information in the register unit.

9. A device as claimed in any of the preceding claims in combination with a number of similar devices in an area in which the movement of individuals carrying characteristic tokens is to be recorded, there being a location device at each entry to the whole area and at each doorway or passageway between rooms in the area, which location devices are coupled to a common register unit.

10. A location system including one or more location devices as claimed in any of the preceding claims, and a number of tokens which generate radio or inductive signals with different characteristics.

11. A system as claimed in Claim 10 in which the tokens transmit signals at different carrier frequencies.

12. A system as claimed in Claim 10 in which the tokens transmit signals at the same carrier frequency and in the form of bursts of carrier frequency pulses separated by break pulses consisting of an absence of carrier frequency, the different characteristics of different tokens being in the number of carrier frequency pulses in a burst.

13. A system as claimed in Claim 12 in which for all the tokens the break pulses are of the same duration.

14. A system as claimed in Claim 13 in which the register unit is sensitive to the length of a break pulse to correct for apparent differences between break pulse lengths due to tokens being at different ranges from the sensors.

15. A system as claimed in any of Claims 10-14 in which the tokens "spit" characteristic signals in random spells with intervals between spells which are long compared with the length of the spells.