WO2009029980A1

WO2009029980A1 - A tracking system

Info

Publication number: WO2009029980A1
Application number: PCT/AU2008/001305
Authority: WO
Inventors: Warwick Taws
Original assignee: Celltek Electronics Pty Limited
Priority date: 2007-09-03
Filing date: 2008-09-02
Publication date: 2009-03-12

Abstract

The invention is a tracking system suitable for use in spaces, such as shopping centres. The space is equipped with a first array of ultrasonic transmitters (23) and a second array of RF receivers (21) to track mobile devices (24). The system comprises a tracking computer (36) that receives RF transmissions via the second array (21) from a mobile device (24) that has received ultrasonic transmissions from plural ultrasonic transmitters (23) of the first array. Based on the received RF transmissions the computer (36) is able to cause the display of a location of the mobile device on a map of the space. It is an advantage of the invention that there is no limit on the number of similarly located mobile devices (24) as there is no risk of signal collision between mobile devices (24). Other aspects of the invention include methods, software and a mobile device.

Description

Title

A TRACKING SYSTEM

Technical Field This invention concerns a tracking system. In general, location systems allow the mobile objects to determine their own locations, whereas tracking systems allow a base station to monitor the locations of mobile objects. Aspects of the invention include a tracking system, a mobile device, software and a method for implementing the system.

Background Art

Beacons and receivers have been used for some time to locate and track mobile objects.

In one known location system a mobile object receives both radio frequency (RF) signals and an ultrasonic pulse from the same transmitter. The mobile device uses the difference in the time of flight between the RF and ultrasonic transmissions to determine its location relative to the transmitter. This information can then be displayed to the user carrying the mobile device, or to other users viewing a computer software interface.

In another known location system, the mobile object emits ultrasonic pulses. A series of receivers mounted in fixed locations measure the time of flight of the pulses and determine the location of the mobile object by triangulation.

Summary of the Invention The invention is a tracking system suitable for use in spaces equipped with a first array of ultrasonic transmitters and a second array of RF receivers to track mobile devices. The system comprises a tracking computer that receives RF transmissions via at least one RF receiver of the second array from a mobile device that has received ultrasonic transmissions from plural ultrasonic transmitters of the first array. Based on the received RF transmissions the computer is able to cause the display of a location of the mobile device on a map of the space.

It is an advantage of the invention that there is no limit on the number of similarly located mobile devices as there is no risk of signal collision between mobile devices. The space may be a shopping mall, hospital, airport or any other public building or large premises but is not limited to these.

The RF receivers may be transceivers.

The calculation of the location of the mobile device may take place on-board the device itself, or it may be conducted by the tracking computer; in this case the tracking computer may transmit the location information back to the mobile device itself, or other mobile messaging devices, for example but not limited to pagers, wireless PDA's, mobile phones.

The first array may comprise a series of hubs spaced 50m from each other, each of which deploys a number of ultrasonic transmitters spaced apart by 25m from each other. Other spatial configurations may be used, depending on physical layout of the space.

Such arrays can determine the accuracy of a mobile device to within 0.5m within the space. Should a mobile device leave the space the arrays can still determine a close location to within 20m using RF triangulation or a supplementary location technology such as a GPS satellite receiver, WiFi or Zigbee or other non-proprietary wireless triangulation system. In addition, a portable or fixed directional receiver can be used to detect a mobile device further away.

Further, a 3 -axis accelerometer sensor inside the mobile device may be used to compute approximate location relative to a known reference point by means of inertial navigation. Traditional inertial navigation systems suffer from accumulated positional errors over time, once the mobile device leaves a position where its exact location is known. Small errors in the inertial positioning hardware/software accumulate until the device obtains correction data by means of detecting proximity to another known location. This invention includes a means of providing several positional reference points around the site, enabling regular re-calibration of the position calculated solely by inertial means in the situation where the mobile device travels beyond the detection bounds of the first array.

An RF transceiver may be installed at each hub, as well as additional RF messaging transmitters. Additional surveillance equipment may be provided in, or around, the space, such as CCTV cameras and security alarm sensors.

Push button alarms may also be installed around the space at known locations and connected to the tracking computer.

The mobile devices may be supplied to personnel to facilitate real time job management, for instance selecting the best located and available person for a task. Such job allocation may also be performed automatically by the system computer, since it is aware of the position of all potential job respondents at the time a job is scheduled.

The location of personnel can be tracked, as well as the history of their recent movements. This tracking is advantageously displayed as an overlay on a map of the space. In the instance personnel travel beyond the detection boundary of the first array, either of two means may be used to determine their location: either by relying on the less accurate positional data provided by the second array; or by accepting a download of stored inertial navigation data from the mobile device when it returns within the detection boundary of the first or second arrays.

The accelerometer in the mobile device may also be advantageously used to detect exceptions to expected behavioural or movement patterns, whether or not the device is within the detection boundary of either array. Examples could include the detection of a slip and fall ('man-down') incident of the user wearing the device (with a time stamp on the incident recorded in the memory of the device), or the detection and recording of an excessive impact to an asset to which the device is fixed (such as an industrial floor polisher). If such incidents occur within the detection boundary of either of the arrays, the location of the incident is also known, otherwise only the time and approximate movement/acceleration signature is known, and is downloaded from the device upon its return within the array boundary. Variables such as movement, impact, tilt and vibration can be detected and recorded in the device, and if appropriate, the occurrence of these can be logged with a time and location stamp.

The personnel may be equipped with additional communications devices, such as cell phones or paging devices, so that they may receive instructions from the RF messaging transmitters to perform tasks. Personnel may use the communication devices to provide information to the tracking computer, for instance to describe the nature of an incident, such as a spillage or an alarm. This information may be input by keypad or a photo may be taken. The location of the communication device is automatically known by tracking the associated mobile device. In addition, the computer software may be used to automatically analyse the positional signature of incidents; for example a cleaner using a mop to clean a wet spill will produce certain repeatable characteristics in the pattern of movement which may allow a software algorithm to detect these spill sites over a period of time, and such results could then be displayed on the floor plan.

Personnel could also be equipped with simple RF signal transmitters to signify alarm or to facilitate provision of some service, for instance that they are ready to retrieve shopping from a store, or to retrieve their car from valet parking.

The communication device may be used to display the current location in the space.

The computer is also able to automatically calculate statistics regarding various types of incidents from the data it collects.

The system can also be used to provide a range of additional functionality. For instance, outside of normal business hours if the system is used to track the location of authorised cleaners, then the burglar alarm sensors could be set and subsequently selectively deactivated and re-activated as authorised personnel, such as cleaners, pass by.

The system could also react to events such as to automatically open alarmed doors in an emergency to allow known security personnel to pass.

In another aspect the invention is a mobile device operable to receive ultrasonic transmissions from a first array of ultrasonic transmitters and to send RF transmissions to a tracking computer via a second array of RF receivers in the tracking system.

The mobile device may be further operable to receive RF transmissions from an array of RF transceivers in the tracking system and to perform location calculations based on signal strength of each of the received RF transmissions. In a further aspect the invention is a method for operating a tracking system for use in spaces equipped with a first array of ultrasonic transmitters and a second array of RF receivers to track mobile devices, the method comprising the steps of: receiving RF transmissions via the second array from a mobile device that has received ultrasonic transmissions from plural ultrasonic transmitters of the first array; and displaying a location of the mobile device on a map of the space, the location based on the received RF transmissions.

In yet a further aspect, the invention provides a method for operating a tracking system for use in a space to track mobile devices, the method comprising the steps of: sending ultrasonic transmissions from plural ultrasonic transmitters of a first array of ultrasonic transmitters arranged in the space a mobile device; sending from the mobile device that received the ultrasonic transmissions from the plural ultrasonic transmitters, RF transmissions to a second array of RF receivers; sending from at least one RF receiver of the second array the RF transmission to a tracking computer; and the tracking computer causing the display of a location of the mobile device on a map of the space, the location based on the received RF transmissions.

In yet a further aspect, the invention is software for implementing the methods described above.

Brief Description of the Drawings

An example of the invention will now be described with reference to the accompanying drawings, in which:

Fig. 1 is schematic view of the system;

Fig. 2 shows a map of the space including a history of locations of two mobile devices; and

Figs. 3 (a) and 3(b) show example call point devices;

Fig. 4 is a map showing the tracking of an asset outside the shopping centre; and Figs. 5(a), (b) and (c) show sample reports that can be produced on the information collected.

Best Modes of the Invention Referring first to Fig. 1, a tracking system 18 will be described that is installed in a shopping centre. The tracking system is based on a local area network, such as a TCP/IP Ethernet LAN or RS485 LAN or similar 20. Cabling or wireless communication points for the LAN may be positioned within the shopping centre so as to not be visible.

The tracking system 18 is comprised of an array of hubs; one hub is schematically shown at 22. Each hub 22 is connected to the LAN 20. The hubs 22 are positioned so that they span the internal space of a shopping centre and are each, for example, 50 meters apart. Each hub 22 is comprised of a number of ultrasonic transmitters 23, such as four as shown, that are nominally but not necessarily spaced 15 to 25 meters apart from each other.

The hub 22 may also include a RF transceiver 21. The transceiver 21 and ultrasonic transmitter 23 can be easily combined into a single piece of hardware. Further, it will be readily understood that while in this example the ultrasonic transmitters 23 and the

RF transceiver 21 are arranged within the same hub 22 they can easily be separated to create a first array of ultrasonic transmitters 23 and a second array of RF transceivers

21. In an environment comprising multiple smaller rooms or divided areas, the system may optionally be configured with only a single ultrasonic transmitter 23 per room, in which case location accuracy is limited to that room. This may be sufficient for some applications.

Mobile devices 24 are also provided. They are typically small units that can be attached to assets that will be tracked using the system 18, such as commercial cleaners

26 and furniture (not shown). A mobile device 24' can also be worn by personnel such as cleaning 28 and security (not shown) staff. These mobile devices 24 are able to receive ultrasonic transmissions from the one or more ultrasonic transmitters 23 of the hubs 22, and in return are able to send RF transmissions to the RF transceivers 21 of the hubs 22. Mobile devices 24 may include an accelerometer that can detect whether the mobile devices 24 are in a particular orientation.

The staff may also carry with them a further mobile communications device, such as a pager 30, mobile phone or personal digital assistant (PDA) 32. These devices 30 and 32 are able to communicate with message transmitters 34 that are also connected to the LAN 20. In this example the message transmitters 34 are excluded from the hubs 22 and can be positioned anywhere on the LAN 20 as required.

A tracking computer 36 is also provided that is connected to the LAN 20. Software is installed on the computer 36 to allow the user of the computer 36 to readily determine the current and previous locations of each mobile device 24. To this end the computer 36 includes a database to store a history of the locations of each of the mobile devices 24 and information received in any incidents. The software also operates the computer 36 to monitor, respond and produce reports on the incidents that occur.

A redundant tracking computer 38 may also be provided to provide back-up to all the operations of the tracking computer 36. To aid this, data stored in the database of computer 36 may be periodically sent to the redundant server 38.

Remote access to the tracking computer 36 can be provided by a further computer 40. In this example the remote computer is connected to the LAN 20, but with security measures in place the remote access could be provided through a web browser in which case the computer 40 need not be connected to the LAN 20. Instead the computers 36 and 40 must be provided with Internet connections.

Further user alarm activators, such as call point devices 42, may be positioned within the shopping centre at various locations. They can be connected to the computer system 36 either via a direct connection to the RF transceiver 21 (not shown) or wirelessly as shown. The call points 42 provide one or more input buttons that can be activated by tenants or suitable people associated with the shopping centre which result in sending a predetermined message to either the computer system 36 or the closest relevant respondent carrying a mobile communication device 30 and 32.

The system can also include CCTV security cameras 44 and other security alarm sensors (not shown) usually associated with security systems in place at a shopping centre.

An example of using the tracking system 18 will now be described.

In use, the ultrasonic transmitters 23 each transmit FM -modulated ultrasonic transmissions at precisely spaced intervals several times a second. That is, each hub 22 controls the timing of the ultrasonic transmissions from its array of ultrasonic transmitters 23 so that each ultrasonic transmitter 23 transmits in a precisely timed sequence to avoid signal clashes. By utilising multiple FM frequencies the problem of acoustic standing waves is overcome by effectively moving the position of the standing wave relative to the portable receiver. Each ultrasonic transmission is also uniquely identified by a data addressing scheme.

Further, the centre (or carrier) frequency of the FM modulation is varied in each transmission by the transmitters 23 of a hub 22. This slightly changes the wavelength of the transmitted ultrasound, thereby slightly changing the position of the standing wave reflections which reduces the possibility of destructive combining at the mobile device.

Ultrasonic transmissions from a plurality of ultrasonic transmitters 23 are received by the mobile devices 24. Compared with pulse transmissions, FM modulation improves immunity to noise and interference at ultrasonic frequencies.

A periodic synchronisation signal, say every hour, is transmitted by RF from nominated RF transceivers 21 to provide mobile devices 24 with a time reference for the timing measurements. Using this time reference, the mobile devices synchronise their internal timing clock to the transmissions. Thus small errors in each mobile device's internal clock are corrected, ensuring that all mobile devices share a common time base. Since a mobile device is able to de-power the RF receiver circuitry for extended periods between time synchronisation broadcasts, a reduced power consumption is achieved.

The mobile devices 24 have processing capability to collect and measure information on the relative distance of the mobile device 24 to each of the transmitters 23. The calculation is based the time delay of each ultrasonic transmissions, and therefore the time-of-flight of each ultrasonic signal from each ultrasonic transmitter 23 to the mobile device 24.

In this example, at predetermined intervals, say once every 10 seconds, the mobile devices 24 send a RF transmission to the RF transceiver 21.

In the event that the mobile device 24 is out of range of the ultrasonic transmissions from the ultrasonic transmitters 23, a secondary means of performing location calculations is provided. The mobile devices 24 accurately measure the received signal strength of the RF transmissions from the plurality of RF transceivers 21 and perform a triangulation calculation based on the relative signal strength of the signal from each RF transceiver 21. The resultant location accuracy is diminished in comparison to the ultrasonic result; therefore the RF calculation is only used as a back-up when the ultrasonic result is not available.

The relative distance information is included in the RF transmission that is sent from the mobile device 24 to the RF transceiver 21. Over time the position of the asset 26 or personnel 28 that is carrying the mobile device 24 changes, meaning the location included in the RF transmission sent from the mobile device 24 also changes. This message is received by one or more RF transceivers 21 and relayed to the tracking computer 36 via the LAN 20.

The calculation of the location of the mobile device is then performed by the tracking computer 36. The tracking computer 36 can transmit the location information to third parties, back to the mobile device 24 via the RF transceiver 21, or from the message transmitter 34 to the mobile communications devices 30 and 32. The location information may be transmitted as a map coordinate, a graphical map image, or a text description of the location, depending on the application.

Using this method, the location of the mobile device will be accurate to within 0.5 meters within the shopping centre, provided that the calculation was derived from the ultrasonic measurements.

If the mobile asset 26 or personnel 28 carrying the mobile device 24 leaves the boundary of the shopping centre building, the array of hubs are able to determine the location of the mobile device 24 to a nominal accuracy of 20 meters. This is performed by RF triangulation as mentioned. This location calculation may also involve the use of a 3 -axis accelerometer sensor inside the mobile device 24 to compute an approximate location relative to a known reference point by means of inertial navigation, as previously mentioned.

The software of the tracking computer 36 provides a user interface that is displayed on the screen of the tracking computer 36, or on the screen of the remote computer 40. The software operates the computer 36 to record all location updates (events) in the database.

In an alternate embodiment the computer 36 does not determine the location of the mobile device 24, instead the mobile device 24 itself does. In this case, the mobile device 24 stores an internal database of geo-spatial information about the site, such as a digital map of the site. The application therefore also requires a visual and/or audible interface on the mobile device which provides navigational information to the user.

This stored information can be used to then present to the user a map 50 of the shopping centre as shown in Fig. 2. In this example, a trajectory of the movement of the mobile device 24' carried by the personnel 28 over a period of time is shown at 60. This clearly shows where the mobile device 24' has travelled. In this example the trajectory shows the previous 15 minutes of locations but this time period is readily adjustable using the user interface of the software.

The spot marked 62 shows the current location of the mobile device 24'. The display could be updated in real-time to always show the previous 15 minutes (or otherwise) of locations. Alternatively, the user can request that the display simply show the current location 62 of the device 24' (without the trajectory) in real time.

Fig. 2 also shows the trajectory of movement of the mobile device 24" carried by the commercial cleaning machine 26 at 64.

The software can also display the location of an asset 26 if it breaches the designated site boundary of the shopping centre, or an area or zone within the shopping centre. As shown in Fig. 4, the location of the mobile device 24" is shown as a flashing icon 80 together with an arrow 82 showing the last known direction of travel of the asset 26. This information will help to recover the asset 26.

The software can produce reports summarising the incidents that were detected. This is shown in Fig. 5 (a) where each dark dot identifies the locations at which incidents occurred. Fig. 5(b) graphs the number of security incidents over a period of time and Fig. 5(c) graphs the number of cleaning incidents over the same period of time. The information collected in the database can be analysed further to provide additional reports. The reports can summarise the time it took to respond to incidents, where the person was located at the time of the incident and how much time had elapsed between the time personnel were last at that location and the time of the incident.

The tracking system can also be used to receive, store and control a response to various instances that occur within the shopping centre as described below.

For example, the mobile device 24' is carried by the personnel 28, who in this case may be a security guard, in a vertical orientation. Should the mobile device 24' change to a horizontal orientation for a preset period without being acknowledged as such by the user by means of pressing a button on the device, then this may indicate an emergency situation, such as the security guard 28 being injured and lying fallen on the ground.

Alternatively the accelerometer may be provided in the mobile device 24" of an asset that is not mobile. Should that asset experience a change in orientation, either up, down, sideways, tilt, or be subject to vibration or impact, information about this can be sent in real-time from the mobile device 24" to the tracking computer 36. The software allows the user to set the sensitivity of allowable movements of each asset. Once this amount has been exceeded the tracking computer 36 can cause a message to be sent in real-time to a pager 30 of the closest security personnel to investigate.

Further, call points 42 can be given to particular tenants and can be fixed inside the tenant's shop. The location of the call point 42 is known by the tracking computer 36. Using the call points 42 the tenants can also watch out for security, first aid or cleaning incidents and provide an alert using the system 18. For example, referring to the call point 42' shown in Fig. 3 (a), buttons 70 are provided that each correspond to a particular event. If the 'cleaning required' button is pressed a predetermined message is sent to tracking computer 36. Based on the known location of the cleaning personal 28, the tracking computer 36 sends a message to the closest cleaner 28. This message is sent via the message transmitters 34 to the mobile communication device 30 or 32 of the cleaner 28.

Fig. 3(b) shows a further call point 42" which provides only one mushroom button. This call point 42" can only send one type of message to the tracking system 36.

A variety of call point 42 configurations can be used, such as single, dual or quadruple buttons, break-glass activation switches, mushroom-head switches, recessed switches, standard tactile switches, mounted in a variety of housings including IP65 rated enclosures. Call points can also be provided in disabled toilets, parents' rooms and car parks. The call points 42 can also include a sensor to reduce nuisance calls, whereby the presence of the user in close proximity to the call point for a minimum period is required for activation (based on human presence monitoring by means of a security sensor).

Further information about an incident can be collected from the personnel 28. For example the personnel 28 can use the camera on the PDA to take a photo of the incident, such as a liquid spill, and cause it to be stored by the tracking computer 36 into the database associated with the record for the event, which also has its location recorded.

The tracking computer 36 may also receive information from additional surveillance equipment, such as CCTV cameras 44. For example, the software can cause the footage from the camera around the time of the incident to be played in synchronisation with the movements of the mobile devices 24 in the shopping centre. Further, the combined display can be stored on the same CD or DVD for archival purposes.

The system 18 can be integrated into the security system of the shopping centre. For example, motion sensors (not shown) may be located throughout the shopping centre to detect the presence of unauthorised persons outside the trading hours. A cleaner can carry the mobile device 24 and depending on their current location, the motion sensors in that security zone are disabled until the cleaners exit the sensor detection zone, at which time the motion sensors are re-enabled. This allows the cleaning staff to safely move around the shopping centre after hours without causing false alarms in the security system.

The system can also be used to collect data about the movements of an asset, such as a shopping trolley or a similar article that a shopper carries to which a mobile device 24 can be attached. As the location information is determined by the computer 36, the computer can also control the CCTV system in order that one or more cameras are directed automatically to follow the provided location in real time to record the shopper's actions. Statistical analysis can then be carried out on the collected information and used for purposes, such as marketing and the layout of merchandise. Advantages of the embodiments of the invention can include: ability to integrate with existing CCTV, security alarm, access control and Ethernet LAN infrastructure; low individual component cost; low cost and easy installation; the architecture is infinitely scalable to suit any sized site and any number of sites (and in this way there may be one tracking computer 36 for multiple sites); the invention is capable of a rapid response to event notifications; multi-channel, duplex wireless architecture provides two-way signalling for the highest signal transmission reliability; lower susceptibility to noise interference by use of FM modulation rather than amplitude modulation (AM); fast system deployment with simple logistics; and can be used to monitor the intruder alarms of tenants' shops within the shopping centre by providing an on-site response.

It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

CLAIMS:

1. A tracking system suitable for use in spaces equipped with a first array of ultrasonic transmitters and a second array of RF receivers to track mobile devices, the system comprises a tracking computer that receives RF transmissions via at least one RF receiver of the second array from a mobile device that has received ultrasonic transmissions from plural ultrasonic transmitters of the first array, wherein based on the received RF transmissions the computer is able to cause the display of a location of the mobile device on a map of the space.

2. A tracking system according to claim 1, wherein the RF receivers are transceivers.

3. A tracking system according to claim 1 or 2, wherein the computer is able to cause the display of the location of the mobile device on a display device of the computer and/or the mobile device.

4. A tracking system according to claim 1, 2 or 3, wherein the calculation of the location of the mobile device is performed by the mobile device.

5. A tracking system according to claim 1 or 2, wherein the calculation of the location of the mobile device is performed by the computer.

6. A tracking system according to claim 5, wherein the computer further operates to transmit the location back to the mobile device itself, or other mobile messaging devices.

7. A tracking system according to any one of the preceding claims, wherein the first array comprises a series of hubs spaced substantially 50 meters from each other, each hub deploys a number of ultrasonic transmitters.

8. A tracking system according to claim 7, wherein each hub includes an RF transceiver and/or additional RF messaging transmitters.

9. A tracking system according to any one of the preceding claims, wherein the mobile device includes a three-axis accelerometer sensor that can provide data from which the approximate location of the mobile device relative to a known reference point by means of inertial navigation.

10. A tracking system according to any one of the preceding claims further comprising equipment provided in, or around, the space, the equipment being one or more of closed circuit television (CCTV) cameras, security alarm sensors and user alarm activators, wherein the computer further operates to receive data from the equipment or to control the equipment.

11. A mobile device operable to receive ultrasonic transmissions from a first array of ultrasonic transmitters and to send RF transmissions to a tracking computer via a second array of RF receivers in the tracking system.

12. A mobile device of clam 11, wherein the mobile device is further operable to receive RF transmissions from the array of RF transceivers in the tracking system and to perform location calculations based on signal strength of each of the received RF transmissions.

13. A method for operating a tracking system for use in spaces equipped with a first array of ultrasonic transmitters and a second array of RF receivers to track mobile devices, the method comprising the steps of: receiving RF transmissions via the second array from a mobile device that has received ultrasonic transmissions from plural ultrasonic transmitters of the first array; and causing the display of a location of the mobile device on a map of the space, the location determined based on the received RF transmissions.

14. Software, that when installed on a computer system, causes the computer system to perform the method of claim 13.

15. A method for operating a tracking system for use in a space to track mobile devices, the method comprising the steps of: sending ultrasonic transmissions from plural ultrasonic transmitters of a first array of ultrasonic transmitters arranged in the space a mobile device; sending from the mobile device that received the ultrasonic transmissions from the plural ultrasonic transmitters, RF transmissions to a second array of RF receivers; sending from at least one RF receiver of the second array the RF transmission to a tracking computer; and the tracking computer causing the display of a location of the mobile device on a map of the space, the location based on the received RF transmissions.