WO2009063115A1

WO2009063115A1 - System for locating minors in large retail facilities

Info

Publication number: WO2009063115A1
Application number: PCT/ES2008/000711
Authority: WO
Inventors: Debora Claros Moreno; Miguel Angel DOMÍNGUEZ DURÁN; Jose Carlos Del Toro Lasanta; Cristina URDÍALES GARCÍA; Francisco SANDOVAL HERNÁNDEZ
Original assignee: Universidad De Malaga
Priority date: 2007-11-16
Filing date: 2008-11-13
Publication date: 2009-05-22
Also published as: ES2325648A1; ES2325648B1

Abstract

The invention relates to a system for locating minors in large retail facilities. The invention enables the use of low-power-consumption wireless networks in order to implement a system that provides a warning when a minor wanders off in a large indoor or outdoor retail facility. The invention includes an installed infrastructure formed by a series of fixed nodes and a set of moving nodes to be located. The invention also includes another set of terminals worn by the adults in charge and intended to receive lost child notifications. Inter-node communication complies with a Zigbee-type standard short-range, low-power-consumption protocol. Each node to be located transmits the identifier thereof and information for locating same. Said information is transmitted using a multi-hop routing algorithm to the central module via the node acting as a gateway. If the central module stops receiving packets containing the identifier of any moving node, said node is considered to be lost and a notification is transmitted to the terminal of the adult in charge.

Description

Title

System for locating minors in large areas.

Technical sector

The present invention falls within the technical sector of wireless communications. In parallel, the invention is related to people tracking devices for various applications, in particular for location on large surfaces.

Prior art

The invention provides a series of advantages to existing systems developed to prevent the loss of minors. There are currently different systems developed for locating mobile targets, although this document will focus on applications dedicated to preventing the loss of minors.

There are a number of inventions that deal with the system for locating minors or systems that warn when a minor leaves a certain area or the person in charge. For its implementation, systems developed specifically for this have been used, devices with already standardized technologies such as RFID and Bluetooth, as well as location services offered by telephone operator companies or the GPS service.

Documents KR20010054255 and JP2000287265 deal with a system consisting of two components, one that carries the minor (slave device) and another that carries the caregiver (master device). The slave component that carries the child emits a radio wave that receives the master component, and when the child departs a certain distance from the caregiver, the master component warns by means of an audible or similar alarm. In the case of JP2000287265, the master device is connected to the mobile phone. The problem with these documents is that the proposed radio technology is very specific and does not meet any standards. Document KR20050022889 deals with a system consisting of two terminals.

Both terminals contain a wireless transceiver and a GPS receiver, by which they know their position. The slave terminal, which carries the minor, sends the position information to the terminal carried by the caregiver, and the latter displays the position of both terminals on a display. At the moment when the caregiver's terminal loses the received signal, it appears in the display a control signal indicating the position of the terminal at the time of loss. The problem presented by both this system and the previous one is that the radio technology proposed for communication between terminals is very specific and does not meet any standard. On the other hand, the GPS service presents as a disadvantage that the objective has to be in an open space and with direct visibility with the satellite. In addition, the GPS receiver has a high power consumption in the time interval in which it receives information from the satellite and processes it.

Document KR20050009454 presents a system similar to that described in document KR20050022889, although the display of the information is not carried out through a display in the terminal carried by the caregiver, but using a PDA.

Document KR20020048170 is about a system consisting of two wireless terminals that communicate through a Bluetooth radio link. At the moment the terminals lose the connection, an alarm is activated in the terminal carried by the caregiver. The advantage of this system is that it communicates by means of a standard protocol, Bluetooth, and this makes it a more easily expandable or integrable system in other systems. On the other hand, there are less consumption protocols than Bluetooh, as is the case with Zigbee. Finally, Bluetooth is a technology that uses a short-range radio communication protocol.

Document KR20030065014 deals with a system similar to the previous one, KR20020048170, with the difference that the information transmitted between the terminals is the voice of the terminal bearers.

Document KR20060022901 presents a telephone service that searches for a lost child through an encryption number. The problem with this type of system is that it cannot be used when the child's phone is switched off or out of coverage.

Document KR20040022314 is about a system that combines mobile telephony and GPS tracking service. The terminals know their location through satellite information (GPS). At the moment when the location of the child's terminal is outside a certain area, the caregiver's terminal automatically makes a telephone call to the child's terminal. If the location is within the zone, it is shown on the mobile screen. GPS tracking can only be carried out, as noted above, outdoors. On the other hand, each telephone call has an associated economic cost.

Document US2005270158 deals with a system dedicated to tracking mobile targets (people or animals) in a specific area. A series of RFID readers controlled by a central system are deployed in the area. Each mobile target carries a tag RFID with an identifier, and when passing near RFID readers the target is maintained. Information on the location of the objective is collected in the control center and sent to a personal electronic device carried by the person who wants to know the location of the objective. The problem with this technology is that it is not possible to track the target in areas that are not close to RFID readers.

WO2004054304 proposes a system based on a short range and ultra-low consumption radio communication technology (Zigbee type) for large enclosures, which requires a previous installation of nodes containing a Zigbee radio communication module along the surface. This system is similar to the system proposed in the previous document, US2005270158, but uses Zigbee type technology instead of RFID technology. An advantage of both types of systems is that they use low cost devices. The disadvantage that they present is that, since they are short-range technologies, when a mobile terminal loses contact with all fixed terminals, it cannot be tracked. It must have deployed an infrastructure dense enough of fixed terminals so that each mobile terminal can remain in contact with at least one of the fixed terminals.

Most of the proposed location systems use GPS and telephony services, but the first case is only applicable to outdoor scenarios and the second one requires areas with telephone coverage, in addition to being a service with an associated economic cost. The case of systems that use short-range standard radiocommunication protocols, such as Zigbee or RFID, presents the problem that, despite the fixed terminal infrastructure deployed for location, at the time the mobile terminal is at a greater distance than the reach of these technologies with respect to a fixed terminal, tracking is no longer possible. In short, this document proposes a system that deploys a certain fixed-node infrastructure along the large area, but that takes advantage of the distributed intelligence capability of wireless sensor networks. These networks communicate with ultra-low consumption Zigbee protocols, which have a short range, but using their distributed intelligence, a mobile node can send a message to a fixed node that is beyond its reach, using as a repeater node any Another mobile node.

Disclosure of the invention. The present invention introduces a novel solution to the use of low-power wireless networks applied to the systems used to prevent the loss of minors in large areas. In this case, the maximum distance of the minor from the responsible adult is not limited by the scope of the technology, but it is possible to keep a minor located along a large enclosure without the need for a large deployment of fixed nodes and without Need for such exhaustive control.

In already patented systems that use low-power wireless technology, Zigbee or RFID type, it is necessary to deploy a series of fixed wireless devices that will receive the information emitted by the mobile nodes to be located. The mobile nodes send their identification to the fixed nodes, but in the case where they do not find a fixed node close enough, the mobile node will be located. In large areas it can be difficult to deploy a network of fixed nodes dense enough to keep located all the mobile nodes that circulate around the enclosure, for this reason this document proposes to make use of the rest of mobile nodes to contribute to the location of the nodes furthest from fixed nodes.

The system is comprised of a set of wireless nodes, which comprise a low-power microcontroller, a Zigbee-type low-power radio module, an antenna, and can include a power module or a USB interface. A part of this set are fixed nodes deployed along the infrastructure of a large area and the rest will be the mobile nodes that carry the minors to keep them located. On the other hand, the adults responsible for minors carry terminals that can be devices with the same technology as the rest of the network nodes, which may include an actuator module (which, for example, produces a visual, audible type alarm or of vibration to notify of the minor's loss). In the case where the adult does not want to carry a specific terminal for this service, notification of loss can be received, even, on the adult's mobile phone.

Each mobile node periodically issues to its neighboring nodes a packet with its identification and additional information that will be used for its location and, through a multisalt routing algorithm typical of meshed networks, the packet is routed to the gateway node, which may be based on the same technology as the rest of the nodes, using both fixed nodes and other mobile nodes as repeater nodes, and this sends all the packets it receives to a central base or module. The frequency with which these packages are sent is configurable. In order for a fixed node to receive the packets emitted by a mobile node, it is necessary that it be at a distance less than the range of the technology used for network nodes. All fixed nodes communicate, through the gateway node, with the base or central module where the system control resides. The connection between the gateway node and the base or central module can be made through a USB interface. This base or central module is aware of the number of mobile nodes to be located at all times, and, if a reasonable time interval has elapsed (which depends on the periodicity with which the nodes send their identification packets), they do not receive identification packets from any of these mobile nodes, it considers that said node is unreachable. At that time, it sends an alarm signal to the terminal of the adult responsible for the minor who carries the unlocated node.

For the estimation of the position of the minors, a location algorithm is used that allows to know the position of the mobile nodes carried by the minors when the network has enough information about the node to be located and its neighbors. This algorithm can be implemented in the central base or module or distributed throughout the network.

Among the advantages of using low-power wireless networks, it can be highlighted that they use a ZigBee radio communication protocol, ultra low consumption, low cost and with a very high battery life of their terminals. This type of systems can be used both outdoors and indoors, and communication between terminals has no associated economic cost. Additionally, despite being short-range technologies, the use of distributed intelligence along the network and, in particular, multi-hop routing, communications from the node to be located to the central system can be established much greater distance than the maximum scope of this technology.

Finally, you can integrate another type of technology that allows you to locate the child at the time when you can not track through the network of wireless nodes. For example, a GPS / GSM module can be added to the node that sends information about the location of the child obtained through the GPS service through the GSM network. The information can reach the base or central module or directly, by SMS, to the adult responsible for the missing child. The use of a GPS module entails high energy consumption, but acceptable at a time as crucial as the loss of a minor. This module can be activated at the moment when the child is so far away that he cannot establish contact with any other node in the network. The inclusion of this new module greatly increases the price of each node.

Description of the figures Figure 1.- Shows the equipment included in the invention: central module (1), gateway node (2), fixed nodes (3) (4) (5) (6), mobile nodes to be located (7) (8) ( 9) (10) (ll) (12) (13) (14) and the terminals carried by the responsible adults (15) (16) (17) (18) (19) (20) (21) (22). The dashed line defines the fixed node infrastructure.

Figure 2.- Wiring diagram of the fixed node that acts as a bridge (2) between the wireless network and the central module (1). The connection (23) can be made through a USB interface.

Figure 3.- Block diagram associated with both a fixed node and a mobile node carried by a minor. They consist of a low consumption microcontroller (24), a Zigbee low consumption radio communication module (25), an antenna (26) and a power module (27).

Figure 4.- Block diagram associated with the gateway node (2). It is similar to Figure 3, but a USB interface (28) is added to connect the node to the central module (1) and the power module (27) is dispensed with.

Figure 5.- Block diagram of a possible implementation of a terminal carried by the adult responsible for a minor. It is similar to Figure 3, but an actuator module (29) is added to warn of the child's loss.

Ways of carrying out the invention

Embodiments of the invention of a non-limiting nature are explained below:

The present invention is conceived as a wireless network of low consumption devices. It is composed of a central module (1) where all the information sent by the wireless nodes of the network is sent to a node that acts as a gateway (2), a set of fixed nodes (3) (4) (5) (6 ) that collect the information of the mobile nodes to be located nearby, the set of mobile nodes to be located (7) (8) (9) (10) (ll) (12) (13) (14) and finally, the set of terminals carried by adults (15) (16) (17) (18) (19) (20) (21) (22), which notify the loss of the minor in their care.

The deployment of the fixed infrastructure is carried out as follows: one of the fixed nodes, which acts as a gateway (2), is connected via a USB interface (23) to the central module (1), and the rest (3) (4) (5) (6) are placed distributed along the area to which the service is to be provided. These nodes should be positioned so that each of them is at a distance less than the range offered by the technology, at least with respect to another node. This ensures that the information can always find a path from any fixed node to the gateway node (2), if necessary, by jumps between nodes. Each fixed node (3) (4) (5) (6) is composed of a low-consumption microcontroller (24), a Zigbee-type low-consumption radio module (25), an antenna (26) and a power module (27). The power module can be a battery, batteries or a connection to the mains. The gateway node, as it has a USB connection through which it is powered, dispenses with the power module (27).

With respect to the mobile node network, the identifiers of the nodes that carry the minor and the responsible adult are uniquely associated at the central base (1). The child carries a mobile node (7) (8) (9) (10) (11) (12) (13) (14) which will be the object that is being kept continuously located. Each mobile node is made up of a low consumption microcontroller (24), a Zigbee low consumption radio communication module (25), an antenna (26) and a power module (27). In this case the power module consists of batteries or a battery. The adult terminal (15) (16) (17) (18) (19) (20) (21) (22) can be implemented in different ways. One possible implementation is that of a device similar to the rest of the mobile nodes to which an actuator module (28) is added. This actuator module activates a light, audible and / or vibratory type alarm. In another possible implementation, any terminal is dispensed with and an SMS is sent to the mobile phone of the adult responsible for the minor.

Once the identification number has been assigned to the nodes, the child's terminal periodically issues its identification, the time of sending and additional information to estimate its position. This packet is routed to the gateway node (2) by a multi-hop algorithm typical of a meshed network, using both fixed nodes and other mobile nodes to reach their destination. In the event that the information is received on a fixed node (3) (4) (5) (6), it is routed to the gateway node (2). If the information is received by another mobile terminal, (7) (8) (9) (10) (11) (12) (13) (14) or (15) (16) (17) (18) (19) (20) (21) (22) in the case where the adult's terminal is a wireless node similar to the rest, this information is forwarded so that it can reach a fixed node (3) (4) (5) (6) or even the gateway node itself (2).

The central module (1) collects all the packets received in the gateway node (2). Consider each node located while receiving packets with the corresponding identifier. Additionally, a location algorithm is used to know the position of the mobile nodes for which sufficient information is available. For this it makes use of the specific information included in the packets sent by the nodes, and must have the packets received by the node to be located and some of its neighboring nodes. It is not always possible to know the location of a mobile node (7) (8) (9) (10) (ll) (12) (13) (14), because information from sufficient neighbors is not always available, but You can always know if the node is lost or not.

If after a period of time, which will depend on the periodicity with which the mobile nodes to be located (7) (8) (9) (10) (ll) (12) (13) (14) send their identifier, they will not receive any packet with that identifier, the smallest carrier of that mobile node is considered lost. At that time a notification of loss is sent to the terminal of the responsible adult (15) (16) (17) (18) (19) (20) (21) (22) whose identifier is associated with the lost mobile node. Upon receiving the notification, the terminal of the responsible adult will activate an alarm, which may consist of the lighting of a light, the emission of an audible signal and / or a vibration. In the event that the adult's terminal is considered his own mobile phone, he will receive an SMS.

If you want to locate the terminal of the child once it is considered lost, to node (7) (8) (9) (10) (l l) (12) (13) (14) you can add two additional modules. A GPS receiver module and another GSM radio communication module. At the moment when the node is lost, it activates the GPS service to know its location, and then sends it to the central module (1) using the GSM module. If the terminal of the responsible adult is your own mobile phone, you can optionally send an SMS with the location information of the missing child.

Claims

1. Location system characterized in that it comprises a wireless infrastructure that in turn comprises the following devices: a central base and a network of fixed nodes and mobile nodes.

2. Location system according to the preceding claim characterized in that one of the fixed nodes, called "gateway node", is connected to the base or central module.

3. Location system according to the preceding claim characterized in that the devices comprising the wireless infrastructure include terminals, which may be similar devices to other mobile nodes to which an actuator module is added, or which may consist of mobile phones or Similar.

4. Location system according to any of the preceding claims characterized in that the wireless, mobile and fixed nodes comprise a low consumption microcontroller, a low consumption communication module and an antenna.

5. Location system according to the preceding claim characterized in that the wireless nodes further comprise a power module.

6. Location system according to the preceding claim characterized in that the power module comprises a battery, a battery or a connection to the mains.

7. Location system according to claims 4, 5 or 6, characterized in that the "gateway node", when not connected wirelessly to the central module, comprises a USB connection through which it is connected to the central module and through which is fed without the need of a power module.

8. Location system according to the preceding claim, characterized in that the sending of information is carried out by means of a multisalt routing protocol of meshed networks, in which the information packet sent by a mobile node is directed to the central module, through the so-called "gateway node", using as repeater nodes both fixed nodes and other mobile nodes, capable of redirecting the received information packets to each other, sending them to the "gateway node", and redirecting notifications to the corresponding terminals.

9. Location system according to the preceding claim characterized in that the communication between nodes, and between nodes and the central module, is carried out by means of a wireless protocol of low consumption, each device being assigned a unique identifier.

10. Location system according to the preceding claim characterized in that the communication between the terminals and the rest of the devices, when the terminals are similar devices to the rest of the mobile nodes, is carried out by means of a wireless protocol of low consumption, assigning each device a unique identifier; or, when the terminals consist of mobile phones or the like, the communication is carried out through mobile technology, for example SMS.

11. Location system according to claims 9 or 10 characterized in that the communication protocol is Zigbee.

12. Location system according to claims 9, 1O or I, characterized in that each mobile node to be located periodically sends information about its unique identifier and about the time of its sending, using the next fixed nodes as repeaters (which collect information from the different nearby mobile nodes), which is collected and stored in a database in the central database or module.

13. Location system according to the preceding claim characterized in that the frequency of periodic sending of information is configurable.

14. Location system according to claim 12 or 13, characterized in that the central module, which supports the functionalities of collecting and storing all the information sent by the nodes, of routing in the network and location of the nodes, considers a unique identifier located concrete while continuing to periodically receive information packets from it, and considers it lost when it is not, sending the relevant notification to the terminal associated to the node whose identifier is referred to, either by wireless communication, or by mobile phone technology (for example SMS)

15. Location system according to the preceding claim characterized in that the terminal incorporates an actuator module that produces, after receiving the notification from the central module, a light, sound or vibration signal or alarm.

16. Location system according to claims 14 or 15 characterized in that the information sent by the mobile nodes also allows its location, either through a location algorithm (only useful when the unique identifier in question is not considered as missing), implemented in the central module or distributed throughout the network; either thanks to the incorporation of a GPS location module (active when the node loses communication with all its neighbors) and a GSM communication module through which it sends its location, either to the central base that sends the appropriate information to the corresponding terminal, either directly to the terminal, if it is a mobile phone or similar, by SMS.