GB2392331A

GB2392331A - Tracking system including a portable GPS receiver

Info

Publication number: GB2392331A
Application number: GB0309425A
Authority: GB
Inventors: Courtney N Walton
Original assignee: CNW Ltd
Current assignee: CNW Ltd
Priority date: 2002-06-28
Filing date: 2003-04-25
Publication date: 2004-02-25
Also published as: GB0309425D0

Abstract

A tracking system is disclosed that is particularly suited to a visitor tracking and analysis system for use in theme parks and holiday or leisure facilities. The system includes a portable GPS receiver (10,Fig2), a base station 24 and a plurality of transmitting devices 28,30. Each transmitting device 28,30 transmits a signal to the portable GPS receiver (10,Fig2) when the receiver comes within a predetermined distance of the transmitting device. The portable GPS receiver (10,Fig2) includes a means for transmitting a location signal to the base station 24 on receipt of an interrogation signal from the base station. The transmitting devices may be located around a perimeter of an area of interest or at a position within an area of interest and the portable GPS receiver may transmit a location signal to the base station 24 on receipt of a signal from a transmitting device. The portable GPS receiver may include a memory for storing information on receipt of a signal from a transmitting device, including time of receipt of signal and location of the portable GPS receiver at that time. The system may comprise a means for collecting information stored in the memory of the portable GPS receiver, wherein the collection means may be provided at an exit from the area of interest. The portable GPS receiver may be incorporated into a wrist band and may include a means detecting removal of the receiver from a person, whereby a location signal may transmitted upon detection of removal. The system may include a camera for taking a digital photograph of each person wearing a GPS receiver and a means for storing the image and an identification code of their GPS receiver. Members of staff in the area of interest may be provided with a PDA wherein the system may transmit the picture of the person wearing the GPS receiver to one or more of the PDA's.

Description

Title: Tracking System Description of Invention

5 The present invention relates to a tracking system, particularly, but not exclusively to a visitor tracking and analysis system for use in theme parks and holiday or leisure facilities.

Systems for monitoring the whereabouts of a child by providing the child with a portable GPS receiver are known, for example from GB2348080, l0 GB2332319, and DE19702998. In these systems, the GPS receiver sends information regarding the position of the child to a base station on receipt of an interrogation signal sent from the base station. In such, systems, however, a parent or cater is not alerted if the child has strayed outside a particular area, until they initiate the sending of an interrogation signal and receive a signal 15 giving the location of the child.

Other tracking systems are known in which a signal containing information relating to the location of a person carrying or wearing a portable GPS receiver is transmitted to a base station at regular intervals. In this case, the location signal is sent to the base station automatically, and it is not 20 necessary for an interrogation signal to be sent from the base station to initiate the sending of a location signal. The base station may include a processor which processes the location information and initiates an alarm sequence if the location information indicates the person has moved outside a pre-programmed area. In order to monitor the locations of a plurality of GPS receivers, the 25 processor must be sufficiently powerful to cope with processing regular location information from a plurality of GPS receivers.

According to a first aspect of the invention, we provide a tracking system including a portable Global Positioning System (GPS) receiver, a base station, and a plurality of transmitting devices, each transmitting device

transmitting a signal to the portable GPS receiver when the portable GPS receiver comes within a predetermined distance of the transmitting device, the portable GPS receiver including means for transmitting a location signal including information concerning the location of the portable GPS receiver to 5 the base station on receipt of an interrogation signal from the base station.

The system may include a plurality of portable GPS receivers, the base station including means to transmit with an interrogation signal a code identifying the portable GPS receiver to be interrogated, each portable GPS receiver having assigned to it a unique code and being programmed to respond 10 to an interrogation signal only when the interrogation signal includes the code assigned to that portable GPS device.

Preferably all or at least some of the transmitting devices are perimeter transmitting devices located around the perimeter of an area of interest, and the portable GPS receiver also includes means for transmitting a location signal 15 including information concerning the location of the portable GPS receiver to the base station on receipt of a signal from a perimeter transmitting device.

Thus, where a child is provided with a portable GPS receiver, not only may a parent or carer be provided with information concerning the location of_ the child on request, but an alert will automatically be raised when a child 20 approaches the perimeter of the area of interest, the perimeter fence of a theme or leisure park for example.

The latter can be achieved without the need for the GPS receiver automatically to send location signals to the base station at regular intervals, and Gus the system according to the invention may be used to monitor the 25 location of a plurality of portable GPS devices without the need to provide the base station with a processor which is capable of processing regular location information from a plurality of GPS receivers. Thus the system according to the invention is particularly suitable for use in a theme or leisure park, where monitoring of the location of a large number of children may be required.

The portable GPS receiver may also include memory and may be programmed to store information in the memory on receipt of a signal from a transmitting device, the information including the time of receipt of the signal from the transmitting device and the location of the portable GPS receiver at 5 that time.

In addition to or instead of perimeter transmitting devices, at least some of the transmitting devices may be local transmitting devices located at positions of interest within an area of interest, in which case, the portable GPS receiver is programmed to store information in its memory on receipt of a 10 signal from a local transmitting device, the information including the time of receipt of the signal from the local transmitting device and the location of the portable GPS receiver at that time.

The local transmitting devices may be located in or at the entrances of buildings within the area of interest.

15 For example, where the system is used in a theme or leisure park the local transmitting devices may be located at certain rides, restaurants or over attractions. If, when Me portable GPS receiver enters a building, and hence receives a signal from a local transmitting device within or at the entrance to building, 20 information concerning the location of the GPS receiver at that time derived from the location of that local transmitting device is stored in the memory of the GPS receiver. If an interrogation signal is received from the base station whilst the GPS receiver is still in the building, the recently stored location information may be used as a basis for the location signal returned to the base 25 station. Ihus, it is possible to obtain information about the location of the portable GPS receiver even when the portable GPS receiver is inside a building and hence may be unable to receive positional information from We GPS satellites.

l The system may further include collection means to collect information stored in the memory of a portable GPS receiver for storing on a central computer system. Such collection means may be provided at an exit of the area of interest, and may be adapted to carry out the information collection on the 5 return of the portable GPS receiver to a return point at the exit Alternatively, or additionally, the base station may be provided with such collection means, and each portable GPS receiver may be programmed to transmit a memory signal to the base station on receipt of a collection request signal from the base station, the memory signal including the information stored in the memory of 10 the GPS receiver.

Thus, information relating to the movement of people carrying a portable GPS receiver can be analysed, and where the system is used in a theme or leisure park, this information can be used to determine trends in movement of people around the park and the popularity of attractions in the park.

15 Preferably, the portable GPS receiver is provided with fastening means for fastening the portable GPS receiver to the body or clothing of a person.

In this case, the portable GPS receiver is provided with detection means for detecting removal of the GPS receiver from the body or clothing of a person and, when removal is detected, for transmitting a location signal including 20 information concerning the location of the portable GPS receiver to the base station. Thus, if a portable GPS receiver is forcibly removed from a child, or if the child removes the GPS receiver, either accidentally or deliberately, an operator at the base station will be alerted.

25 Preferably the portable GPS receiver is powered with one or more batteries and is programmed to transmit a location signal including information concerning the location of the portable GPS receiver to the base station when either the battery power is low or a malfunction in the GPS receiver is detected.

Thus, an operator at the base station will be informed that the GPS receiver has a low battery or is malfunctioning, and can therefore take the necessary steps to replace it with a new GPS receiver.

Preferably the portable GPS receiver is incorporated in a wrist band.

5 Preferably, members of staff working in the area of interest are each provided with a portable GPS receiver, the base station includes alerting means i which, when a location signal is transmitted to the base station, automatically transmits an interrogation signal to the GPS receivers of the members of staff and thus obtains information concerning the locations of the members of staff.

10 This enables an operator at the base station to identify the member of staff closest to the GPS receiver that transmitted the original location signal. Thus, if person with that GPS receiver requires assistance, the operator can then relay information concerning that person to the nearest member of staff, thus minimising the time taken to provide the assistance required.

15 Preferably, the system includes a camera for taking a digital photograph of each person wearing a GPS receiver and means for storing the image along with their personal details and the identification code of their GPS receiver.

Thus, if it is necessary to locate that person, members of staff may be provided with a photograph of that person to assist in the search.

20 Preferably each member of staff is provided with a PDA, and the system further includes means for transmitting the picture one or more of the PDAs.

Preferably communication between the base station, the transmitting means and the portable GPS receivers is achieved using a wireless communication system, for example, using radio waves.

25 Signals between the or each portable GPS receiver and the base station may be transmitted via a relay station.

(RT An embodiment of the invention, hereinafter referred to as "Geocare", will be described with reference to the accompanying drawings of which,!

FIGURE 1 is an illustration of a portable GPS receiver for use in a system according to the invention, the portable GPS receiver being incorporated in a wrist band and hereinafter referred to as a "geobangle", FIGURE 2 is an illustration of the geebangle of Figure 1 fastened 5 around the wrist of a child, FIGURE 3 is an illustration of the internal arrangement of parts within the geobangle of Figures 1 and 2, and FIGURE 4 is an illustration of a cellular radio communications network for use in a system according to the invention, and 10 FIGURE 5 is a flowchart illustrating the operation of a base station of a system according to the invention, and FIGURE 6 is a flowchart illustrating the operation of a relay station of a system according to the invention, and FIGURE 7 is a flowchart illustrating the operation of a local transmitting 15 device of a system according to the invention, and FIGURE 8 is a flowchart illustrating the operation of the 'geobangle' shown in Figures 1, 2 and 3 and FIGURE 9 is an illustration of an example of the locking mechanism of a 'geobangle', Me 'geobangle' in the unlocked position, and 20 FIGURE 10 is an illustration of the 'geobangle' of Figure 9 in the locked position. (R -) Geocare aims to provide parents enjoying the attractions at amusement/theme parks, holiday and leisure venues, with an increased sense of security for the safety and protection of their children whilst the family relax 25 and enjoy the excitement and attractions on offer. In the event of an emergency, a child becoming lost or separated from the family group, our technology offers the ability to pinpoint a child's location instantly, displaying their position on a digital map. Our system operates on several layers simultaneously. Woven into the fabric of a Geocare solution? are functions that

provide management teams with in depth analysis of visitor movements individually or on mass. By integrating GPS data through a designated radio platform, our system in effect creates a digital safety umbrella that provides protection, security and peace of mind to families enjoying valuable leisure 5 time. Our focus is to create an invisible link, a safety harness between parents, children and staff.

As well as elevating the safety profiles of our clients, the 'geobangle' 10 is designed to be worn by children and offered as a service on entry for hire. It has the potential to generate considerable revenue. Results in market research 10 have shown that 84% of families asked said that they would feel safer and more secure with a Geocare Solution. Applying the technology of remote data acquisition to a basic human instinct of protecting the personal safety of children and family is commercially, we believe, a winning formula. Our solution has the ability to be moulded into a unique management tool providing 15 a seamless link between safety, security, analysis and revenue income.

The sites targeted are often vast, stretching over acres of land that include indoor and outdoor locations. Visitor figures can swell to anything up to 30,000 per day. The combination of these elements with a child's innocence, the way society is at the moment, and us, as parents of young children, acutely 20 recognising the number of dangers poised by members of our society, often results in streams of fraught and anxious parents making their way to security staff for assistance and help in finding their separated and lost children (I) Geocare2s key motivation is to significantly reduce the time parents spend separated from their lost children. Our purpose is to enrich the level of security 25 and safety for visitors to Amusement and Theme Parks. The 'geobangle' 10 we believe, will lower the anxiety and insecurity experienced by parents and help the family group to relax an enjoy their day.

In this example, each portable GPS receiver for use in a system according to the invention is incorporated in a wrist band which is adapted to be

fastened around the wrist of a child. The wrist band and GPS receiver combination is hereinafter referred to as a 'geobangle' 10, and is illustrated in Figures 1, and 2.

The 'geebangle' 10 includes a miniature GPS receiver unit 12, 5 iTRAX02 for example, and aerial 14, and in this example is integrated into a radio platform. In order to facilitate integration into the radio platform, the geebangle' 10 is provided with a radio frequency transceiver 16, set at 173 MHz with a 0.5 mile range.

The 'geobangle' 10 also has substantial memory 17 for logging 10 movements. In this example, the memory 17 is an EEPROM 1MB memory. A printed circuit board 20 is also provided to control operation of the GPS unit 12 to facilitate storage of information in the memory 17.

With a 10 hour battery pack 22, the portable GPS receiver 12 is housed within a robust, plastic mounting 18 adjustable in size and can be worn on the 15 wrist or a belt. The plastic mounting 18 completely encases the GPS receiver unit 12, the ariel 14, the RF transceiver, and the memory 17, and protects these components from mechanical or environmental damage.

Shockproof and waterproof the 'geobangle' 10 is a lockable device that is released with a key and is designed to be tamperproof. A suitable 20 mechanism for locking the 'geobangle' is described in detail below, and is illustrated in Figures 9 and 10.

The 'geobangle' 10 is a passive logging device that receives logistical data from satellites every 30 seconds or local radio data when appropriate. It only transmits that information under five conditions, and these conditions will 25 be discussed further below.

Where the system according to the invention incorporates a plurality of portable GPS receivers, as in this example, it is necessary to identify each one with a unique code or identification number.

In this example, the 'geobangle' identification number is software encoded. Every 'geobangle' 10 that is produced will have the same program except that the ID number will be incremented by 1 each time. This is a common practice where a serial or ID number requires encoding into a product.

5 The power supply for the 'geobangle' 10 is a battery pack 22 comprising (a -) 3 x V600 Varta NIMH (Nickel Metal Hydride) batteries. These give a 10 hour usable cycle before recharge and maybe more if we can limit power consumption in certain circuit areas. The battery pack 22 of the 'geobangle' 10 is recharged once the 'geobangle' placed back into a 'docking station', which is 10 located at a return point which may be provided close to an exit of the area of interest, in this example, the amusement or theme park or holiday and leisure venue. The onboard EEPROM 1MB memory 17 of the 'geobangle' 10 is capable of storing a considerable amount of data, for example 240 entries of 15 locations and times of where the 'geobangle' 10 has been in that day may be stored. This data may then be downloaded when the 'geobangle' is returned to a base station, as will be discussed further below.

The internal arrangement of the various parts 14, 16, 17, 18, 20, 22 of the 'geobangle' 10 is illustrated in Figure 3.

20 The communications protocol for the 'geobangle' is illustrated in a flowchart shown in Figure 8. Referring to the flowchart, it can be seen that geobangle' is programmed with a radio counter which is incremented until the radio counter reaches a programmed limit. Once the limit is exceeded, the geobangle' attempts to obtain location information using the GPS receiver unit 25 12. If a GPS signal is available the 'geobangle' stores the time and GPS derived positional information in the memory 17 of the 'geobangle', and resets the radio counter. Typically, the 'geobangle' will log its position in this way every 8 seconds, although longer time internals, 30 seconds for example, may be used.

If a GPS signal is not available, the 'geobangle' increments a GPS counter, and repeats the process until either a GPS signal becomes available, or the GPS counter exceeds a programmed limit. When the GPS counter exceeds the limit, the 'geobangle' transmits an error message to the base station 24.

5 As mentioned above, the 'geobangle' 10 has 5 programmable conditions in which it 'wakes up' and transmits a location signal including information relating to its position back to base. These conditions are: (a) a child is reported lost and an interrogation signal is received from a base station requesting its current position; 10 (b) an interrogation signal is received from the base station requesting a total log download including current or most recent position; (c) somebody is trying to remove the 'geobangle' 10 unofficially from the wearer or the unit has become defective; (d) the battery reaches a pre-set battery low threshold; 15 (e) a visitor wearing a 'geobangle' 10 is exiting the park and a total data download is made to the central PC after its removal from the person.

(Arm) In addition to the portable GPS receiver or 'geebangle' 10, the 'GeocareA system also includes a base station 24. The base station 24 is preferably located at or near a main entrance to the area of interest, and is provided with at least 20 one computer programmed with a software package which facilitates the receiving and sending of signals from or to the portable GPS receiver 10 and the processing of these signals. In addition, the return point discussed above in relation to the provision of a docking station to recharge the battery pack 22 of a 'geobangle' may be provided at the base station 24. = (Rrn) 25 The software package, also referred to as 'Geocare software', is user -

friendly, and, amongst other features, has the ability to handle radio transmission and reception. It is a combination of advanced localised mapping, interactive information including visitor and staff database, visitor

movements/footprints and graph producing analytical functions. The current software prototype has the capacity to handle 9999 'geobangles'.

The software package also provides an operator with access to a database for visitor and 'geobangle' information. Once a parent has opted to 5 use a 'geobangle' 10 for the day the personal details of the wearer including contact details are entered into the database. A visitor identification number is immediately allocated and a corresponding 'geobangle' number is scanned into the database. The activated 'geobangle' 10 can then be issued. In this example, the system includes a camera for taking a digital picture of the wearer, 10 and the software package automatically records the digital image of the wearer and enters the picture into the database. This function is designed to assist members of staff on the ground with identification, as they move through the crowds of people to locate the lost visitor, as will be discussed in more detail below. 15 The base station 24 is also provided with means to generate and send an interrogation signal to a 'geobangle' 10, to request information about the location of the 'geebangle' 10. In this example, as the system includes a plurality of 'geobangles', the interrogation signal includes not only a signal requesting location information, but also a signal indicating the identification 20 number or code of the 'geobangle' 10 to be interrogated.

The 'geobangle' 10 is programmed to respond to an interrogation signal only if the identification number sent in the interrogation signal corresponds to its own identification number. The 'geobangle' 10 is programmed to respond to an interrogation signal by sending a location signal containing information 25 concerning the location of the 'geobangle', as determined using the GPS receiver unit 12 and aerial 14, the time at which the location was determined, and the destination of the signal, i.e. the base station 24, back to the base station 24.

This process is illustrated in Figure 8, and it can be seen that the geobangle' constantly monitors for signals, and if a signal is received with an appropriate preamble, the 'geobangle' checks the ID number given in the preamble. If the ID numba does not match the ID number of the 'geobangle', 5 the 'geobangle' returns to monitoring for further signals and does not take any action in response to the signal received. If, on the other hand, the ID does match, then, if the signal was an interrogation signal transmitted by either the relay station 26 or the base station 24, then the 'geobangle' processes the signal and transmits the appropriate date to the relay station 26 or base station 24, in 10 this case in the form of a location signal.

Providing the infrastructure, the communication platform for all the various elements of a Geocare system is a cellular, radio (RF) network represented in Figure 4, operating on the license exempt frequency of 173MHz.

At this frequency the quality of the signal is a lot less 'clingy' and has greater 15 penetration of obstacles such as buildings, trees and other structures. The base station 24 is considered as the point at where the interrogation signal is generated and processed and is linked to the main PC.

Whilst the radio network preferably operates at 173 MHz, any alternative, suitable frequency may be used instead. For example the RF 20 system may operate at a frequency of 868 MHz.

It was originally considered that more than one base station 24 might have to be used. In practice this may still be true over large areas where a single base station 24 may be out of communication range (1/2 mile). In reality a computer server could be incorporated on a larger site, which could be in 25 contact with any number of base stations. This would also increase the points at where visitor information could be assessed.

Thus, the base station 24 includes an RF transmitter for transmitting an interrogation signal to the base station 24, and an RP receiver for receiving a location signal from a 'geobangle' 10.

The interrogation and location signals may be transmitted directly between the base station and the 'geobangle' 10. In this example, however, transmitting and receiving the signal from the interrogated 'geobangle' 10 is what is referred to as 'relay station' 26. The relay station 26 comprises of a 5 single channel transmitter and receiver unit. This relay station 26 enters into direct communication with the 'geobangles' 10 and re-routes signals from the geobangle' 10 to the base station 24 and from the base station 24 to geobangle' 10.

A flowchart illustrating the operation of the relay station is shown in 10 Figure 6. On receipt of a signal, the relay station determines whether the signal is from the base station 24, by determining if the signal includes an identification number or code of a 'geobangle', in which case, it transmits the signal to the appropriate 'geobangle', or if not, the relay station then determines if the signal is from a 'geobangle', by determining if the destination 15 information included in the signal relates to the base station 24, in which case the relay station transmits the signal to the base station 24.

Preferably, the relay station 26 should be provided with a transmit/receive RF switch to permit use of a single aerial for both transmitting and receiving of radio signals.

20 The system also includes a plurality of transmitting devices, each transmitting device transmitting a signal to a 'geobangle' 10 when the geobangle' 10 comes within a predetermined distance of the transmitting devices. There are two sorts of transmitting devices, local transmitting devices 28, hereinafter referred to as local or indoor tags, and perimeter transmitting 25 devices 30, hereinafter referred to as perimeter tags.

In this example, the transmitting devices 28, 30 are low power RF transmitters, but they may have a variable power control or be provided with a selection of attenuators so that the range of each transmitting device 28, 30 may be set to an appropriate value during installation of the transmitting devices 28,

30. Moreover, in order to ensure improved control over the area covered by the transmitting device 28, 30, a leaky feeder may be used instead of a standard aerial. The cellular nature of the system is created via the local and indoor tags 5 28. These are very low powered devices, which each have a unique ID number, and which cause a 'geebangle' 10 to log its position when a 'geobangle' 10 comes within a certain proximity. All the visitor analysis data generated by the system, originate from these tags 28. These tags 28 provide a position and time stamp on the data stores within the memory 17 of the 'geobangle' 10.

10 Therefore once downloaded, this information can be used to create a picture of guest movements. These tags 28 could be indoors at restaurants, shops, rest areas or outside by rides, attractions and queuing areas etc. In other words, each 'geobangle' 1O is programmed to store information in its memory 17 on receipt of a signal from a local tag 28, the information 15 including the time of receipt of the signal and the ID number of the local tag 28.

A signal from a local tag 28 is received by the 'geobangle' 10 when the geobangle' 1O comes within a predetermined distance of the local tag 28.

A flowchart illustrating operation of each local tag 28 is shown in Figure 7. Each local tag 28 transmits a signal including information relating to the tag 20 ID number and the time, at periodic intervals, in this example approximately once every 30 seconds. The operation of the 'geobangle' when it encounters a local tag 28 is shown in Figure 8. The 'geebangle' constantly monitors the airwaves for radio signals and when a signal is received with an appropriate preamble, the 'geobangle' checks the ID number given in the preamble. If the 25 ID number does not correspond to an ID number of a local tag 28 the geobangle' simply continues monitoring for signals and takes no furler action in relation to the signal received. If, on the other hand, the ID number matches that of a local tag 28, the 'geebangle' determines that the signal has been transmitted by a local tag 28, and the 'geebangle' logs the time and the ID

number of the local tag 28 given in the signal received from the local tag 28, and resets the radio counter.

To monitor unauthorized exit or the forced removal of a child wearing ageobangle' 10 is the 'Geofence'. In effect, a digital boundary to the system 5 and is created by installing tags called 'perimeter tags' 30 around the outer-

limits 32 of the area of interest. These perimeter tags 30 work in exactly the same way as the local tags 28, however, when they come within close proximity to the 'geobangle' 10 they are programmed to initiate a location signal to be sent back from the 'geobangle' 10 to the base station 24 via the relay station 26.

10 The software at the base station 24 is programmed to raise an alarm, informing the operator back at base that someone wearing a 'geobangle' 10 is trying to exit the area of interest via an unofficial exit.

Operation of each perimeter tag 30 is illustrated in Figure 7. As with local tags 28, each perimeter tag 30 transmits a signal including information 15 relating to the ID number of the tag 30, periodically, in the example, twice per second. The operation of the 'geobangle' when it encounters a perimeter tag 30 is illustrated in Figure 8. The 'geobangle' constantly monitors the airwaves for radio signals, and when a signal is received with an appropriate preamble, the geobangle' checks the ID number given in the preamble. If the ID number 20 does not correspond to an ID number of a perimeter tag 30, the 'geobangle' continues monitoring for signals and takes no further action in relation to the signal. If, on the other hand, the 'geobangle' recognises the ID number as that of a perimeter tag 30, a tracking flag is set, and the 'geobangle' transmits a location signal, including information concerning the location of the 25 'geobangle' derived from the GPS, to the base station 24. Receipt of the location signal at the base station 24 alerts the operator to the presence of a geobangle' at or near the perimeter of the area of interest.

Prior to implementing the system according to the invention, the selected area to be covered by the system is surveyed, the GPS co-ordinates plotted and

a datum point taken. The aim of this is to create a very accurate digital grid system map of the area, where the co-ordinates are known and fixed. Any changes on GPS North, South, East or West co-ordinates will correspond to a new physical position. This grid provides the substructure for the digital image 5 of the area to be superimposed, so co-ordinates generated by a moving visitor can be displayed visually on a map instead of by a set of co-ordinates. In addition, using specialized computer software simulation, it is possible to predict reception strengths and field patterns throughout the defined area. This

will mean that the radio stations can be positioned for optimal performance.

10 Tracking of visitors outdoors is achieved through the use of the GPS system. The GPS receiver unit 12 is in continuous dialogue with any number of the 24 GPS satellites, and once and interrogation signal has been received from the base station 24, a location signal including information about the location of the 'geobangle' derived from the GPS satellites' signals is transmitted to the 15 base station 24. The software package at the base station 24 processes the location signal and provides a visual indication of the location of the geobangle' on the map of the area of interest. If desired, the 'geobangle' may be programmed to continue to send location signals at periodic intervals after receipt of the initial interrogation signal, every 20 seconds for example, so that 20 Me software package can provide a continuously up-dated visual indication of the location of the 'geobangle' on the map of the area of interest.

Similarly, if a 'geobangle' comes within a certain proximity of a local transmitting device 28 whilst outdoors, as discussed above, We position logged by the 'geobangle' can be derived from the GPS signal.

25 If, however, the wearer of the 'geobangle' enters a building, GPS data may not available as the view to the satellites are restricted. As buildings are not generally movable, they- have fixed co-ordinates which relate to architectural plans and drawings. Such a plan or drawing of the site may be

used to identify a suitable grid system, and local transmitting devices 28 can be installed at the grid intersections within the buildings.

As discussed above, the local transmitting devices 28 each trigger a passing 'geobangle' 10 log its position, i.e. to store a tag ID number and time 5 record in the memory 17 of the 'geobangle' 10. If the position of a 'geobangle' 10 is then requested whilst the 'geobangle' is still in the building, the location signal transmitted back to the base station 24, instead of including positional information derived from the GPS receiver, may include either the number of the local transmitting device 28 which triggered the 'geobangle' which in turn 10 can be related to a plan of the building that is superimposed over the grid, or simply the last GPS derived location of the 'geobangle' stored in the memory 17 of the 'geobangle'. Thus, the operator at the base station 24 can receive an approximate indication of the location of the wearer of the 'geobangle' even when GPS signals are unavailable. The grid system will also include features 15 such as entrances and exits.

If a child or other person carrying a portable GPS receiver 10 is reported as being lost, the system operates as follows. Once the call reaches an operator at the base station 24 to find a lost visitor, the visitor's name or ID number is entered into the database and the details stored on the database when the visitor 20 was allocated a 'geobangle' 10 are recalled, and the Cgeobangle' number is identified. An interrogation signal is then sent to the 'geobangle', and when a location signal is received in response, the signal is decoded and the results, i.e. the location of the Cgeobangle' is then instantaneously displayed on the map of the area of interest. This process is illustrated in Figure 5. If desired the 25 location information may be stored on the database.

The software is provided with a time out facility such that if a location signal is not received in reply to the interrogation signal within a predetermined time frame, the software will display a prompt asking the operator whether he wishes to abort the process or retry.

If a digital image of the visitor was stored on the database, then a copy of the picture may be provided to members of staff, and thus the picture can be used to assist members of staff in finding the visitor.

Preferably all or at least some of the members of staff working in the 5 area of interest are also each provided with a 'geobangle', in which case the software may automatically run a poll of all security or staff members wearing a geobangle' 10, by sending out an interrogation signal to all the 'geobangles' issued to members of staff and using the information provided in the returned location signals to display the positions of the members of staff on the map of 10 the area of interest. The operator then selects which member of staff is closest in this instance to the lost visitor. Information can then be relayed to the nearest member of staff, thus rapidly reducing search time.

A later application may be the use of CCTV cameras, which could be linked via a radio link to the computers at the base station 24. This may be a 15 useful resource if a child went missing and visual pictures were required to show his or her position. The cameras would be directed according to the radio/GPS data previously received from the 'geobangle' 10. The operator back at the base station 24 could have direct visual contact with the lost visitor.

Staff could then be directed to the person using their short-range personal radio 20 conununications equipment.

As indicated above, the 'geobangle' is also programmed to transmit a location signal including information concerning the location of the geobangle' to the base station 24 when either the battery 22 power is low or a malfunction in the GPS receiver is detected by virtue of the GPS counter 25 exceeding its predetermined limit as discussed above with regard to Figure 8.

Preferably, the location signal also includes an indication that battery power is low or a malfunction has been detected, so that an operator at the base station 24 is alerted to the condition of the 'geobangle'. The operator can then issue a member of staff with a replacement 'geobangle' and have the member of staff

find the wearer as outlined above, so that the member of staff can swap the defective 'geobangle' with its replacement. The operator may then amend the database to ensure that the replacement 'geobangle' number is logged to the database record for that visitor.

5 In theory the system has endless possibilities given enough time and money. However, incorporating PDA units into the system would prove in our opinion an excellent accessory. Utilising existing LAN (Local Area Network) technology, these would integrate with the base station computer and each PDA would be addressable. This would allow personnel on the ground to view, on 10 their PDA, the digital map pinpointing the child's whereabouts, and/or, where a digital image of the visitor was stored on the database, a picture of the lost visitor. 3 An advantage of the invention is that as the 'geobangle' 10 has the ability to store data, it is possible to trace a 'visitor footprint'. Thus, for 15 example, if an incident such as an assault occurs, and the victim or omer party -

can identify the perpetrators, the information saved in the memory 17 of the geobangle' could be used to assist in preventing the perpetrators from leaving the area of interest before being caught, and in catching the perpetrators. If wearing a 'geobangle' 10 were compulsory it would naturally deter 'anti-social 20 behaviour'.

In effect, the 'geobangle' 10 has the capacity to remember 240 positions with time stamps of where it has been in that day. Preferably, as soon as that bangle comes into the proximity of base station 24, me 'geobangle' receives an collection request signal from the base station 24, and me frequency it receives 25 from that base station 24 cross-examines the 'geobangle' 10. In response to the collection request signal, the information stored in the memory 17 of the geobangle' 10 is transmitted from the 'geobangle' 10 to the base station 24, --

where it may be retrieved and displayed on the digital map. So, in the flowchart in Figure 8, the appropriate data transmitted when the 'geobangle'

processes a collection request signal includes all the information stored in the memory 17 of the 'geobangle'.

Theoretically, if all visitors were issued with a 'geobangle' 10 on entry and an incident did occur, this function would enable an incident to be traced 5 back, the footprints of where that visitor has been would be clearly visible and therefore anybody involved could be identified.

The information stored and retrieved from the memory 17 of the geobangle' 10 has dual purpose. The 'visitor footprint' could be used solely as a security measure, but that data could be analysed to produce reports or 10 snapshot analysis. The management teams of a theme or amusement park view their facility as a product. By the strategic placement of our local tags 28 around the site, in restaurants, rides or areas of interest etc., management could gain an unique and valuable commercial insight into how visitors interact with their product. Places and times could be identified where congestion happens, 15 what time it happens and queuing times. Management could determine more effectively peak times and where they occur. The current prototype system has the ability to co-ordinate 999 of these local tags.

Instead of a collect request signal being transmitted to the 'geobangle' when the 'geobangle' comes into the proximity of the base station as described 20 above, the computer(s) at the base station 24 may be programmed such that a collection request signal may be transmitted at the request of an operator.

Alternatively, or additionally, the docking station to which a 'geobangle' is returned for recharging of the battery 22 may be provided with collection means for collecting the information stored in the memory 17 of We 25 'geobangle' for storing on a central computer system. This would typically be done when the visitor to whom the 'geobangle' had been allocated is exiting the area of interest.

A mechanism whereby the 'geobangle' 10 may be locked onto the wrist of a wearer is illustrated in Figures 9 and 10, which show a 'geobangle' with a

wrist band 34, the wrist band 34 being provided with a ratchet portion 36 at a free end of the wrist band 34. The ratchet portion 36 is received in a locking socket 37 provided adjacent to the plastic mounting 18, the locking socket 37 having mounted therein a corresponding ratchet shaped locking member 38 5 connected to a key receiving part 40 by means of a helical spring 42. The key receiving part 40 is generally circular with two projecting engagement formations and is received in a correspondingly shaped aperture 37a in the locking socket 37. The key receiving part also includes a specially shaped key hole, which in this example is generally square.

10 When the receiving part 40 is aligned with the correspondingly shaped aperture 37a, as shown in Figure 9, the ratchet portion 36 of the wrist band 34 may be inserted into and removed from the locking socket 37. To lock the geobangle, onto the wrist of a wearer, the ratchet portion 36 of the wrist band 34 is inserted into the socket 37, a key is inserted into the key hole and the key 15 receiving part 40 pressed into the socket 37 against the biasing force of the spring 42, and rotated so that the projecting formations engage with the socket 37 and prevents the key receiving part 40 from being urged by the spring 42 into the aperture 37a. The spring 42 thus acts on the locking member 38, urging it into engagement with the correspondingly shaped ratchet portion 36 of 20 the wrist band 34. Thus, the 'geobangle' is locked on the wrist of a user, and cannot readily be removed without use of a key.

In the present specification "comprises" means "includes or consists of"

and "comprising" means "including or consisting of'.

The features disclosed in the foregoing description, or the following

25 claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1. A tracking system including a portable Global Positioning System (GPS) receiver, a base station, and a plurality of transmitting devices, each 5 transmitting device transmitting a signal to the portable GPS receiver when the portable GPS receiver comes within a predetermined distance of the transmitting device, the portable GPS receiver including means for transmitting a location signal including information concerning the location of the portable GPS receiver to the base station on receipt of an interrogation signal from the 10 base station.

2. A tracking system according to claim 1 wherein the system includes a plurality of portable GPS receivers, the base station including means to transmit with an interrogation signal a code identifying the portable GPS receiver to be 15 interrogated, each portable GPS receiver having assigned to it a unique code and being programmed to respond to an interrogation signal only when the interrogation signal includes the code assigned to that portable GPS device.

3. A tracking system according to claim 1 or 2 wherein all or at least some 20 of the transmitting devices are perimeter transmitting devices located around the perimeter of an area of interest, and the portable GPS receiver also includes means for transmitting a location signal including information concerning the location of the portable GPS receiver to the base station on receipt of a signal from a perimeter transmitting device.

4. A tracking system according to any preceding claim wherein the portable GPS receiver also includes a memory and is programmed to store information in the memory on receipt of a signal from a transmitting device, the information

including the time of receipt of the signal from the transmitting device and the location of the portable GPS receiver at that time.

5. A tracking system according to any preceding claim wherein at least 5 some of the transmitting devices may be local transmitting devices located at positions of interest within an area of interest.

6. A tracking system according to claim 5 wherein the portable GPS receiver is programmed to store information in its memory on receipt of a IO signal from a local transmitting device, the information including the time of receipt of the signal from the local transmitting device and the location of the portable GPS receiver at that time.

7. A tracking system according to claim 5 or 6 wherein the local 15 transmitting devices are located in or at the entrances of buildings within the area of interest.

8. A tracking system according to any preceding claim wherein the system further includes collection means to collect information stored in the memory of 20 a portable GPS receiver for storing on a central computer system.

9. A tracking system according to claim 8 wherein such collection means are provided at an exit of the area of interest.

25

10. A tracking system according to claim 9 wherein the collection means is adapted to card out the information collection on me return of the portable GPS receiver to a return point at the exit.

11. A tracking system according to any one of claims 8 to 10 wherein the base station is provided win collection means, and each portable GPS receiver is programmed to transmit a memory signal to the base station on receipt of a collection request signal from the base station, the memory signal including the 5 information stored in the memory of the GPS receiver.

12. A tracking system according to any preceding claim wherein the portable GPS receiver is provided with fastening means for fastening the portable GPS receiver to the body or clothing of a person.

13. A tracking system according to claim 12 wherein the portable GPS receiver is provided win detection means for detecting removal of the GPS receiver from the body or clothing of a person and, when removal is detected, for transmitting a location signal including information concerning the location 15 of the portable GPS receiver to the base station.

14. A tracking system according to any preceding claim wherein the portable GPS receiver is powered with one or more batteries and is programmed to transmit a location signal including information concerning the location of Me 20 portable GPS receiver to the base station when either the battery power is low or a malfunction in the GPS receiver is detected.

15. A tracking system according to any preceding claim wherein We portable GPS receiver is incorporated in a wrist band.

16. A tracking system according to any preceding claim wherein members of staff working in the area of interest are each provided with a portable GPS receiver, the base station includes alerting means which, when a location signal is transmitted to the base station, automatically transmits an interrogation signal

r1 to the GPS receivers of the members of staff and thus obtains information concerning the locations of the members of staff.

17. A tracking system according to claim wherein the system includes a 5 camera for taking a digital photograph of each person wearing a GPS receiver and means for storing the image along with their personal details and the identification code of their GPS receiver.

18. A tracking system according to claim 17 wherein each member of staff 10 is provided with a PDA, and the system further includes means for transmitting the picture one or more of the PDAs.

19. A tracking system according to any preceding claim wherein communication between the base station, the transmitting devices and the 15 portable GPS receivers is achieved using a wireless communication system.

20. A tracking system according to claim 19 wherein communication between the base station, the transmitting devices and the portable GPS receiv r is achieved using radio waves.

21. A tracking system according to claim 19 or 20 wherein signals between the or each portable GPS receiver and the base station are transmitted via a relay station. e 25

22. A tracking system substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

23. Any novel feature or novel combination of features described herein and/or in the accompanying drawings.