Patent Description:
Losing sight of a child who should be supervised is an alarming event, which on occasion can result in the child coming to harm. Loss or theft of a valuable object can also cause emotional and financial distress. Technology can be used to help prevent such incidents.

Numerous examples of parent-child separation alarms have been proposed. In some examples, a first device is associated with a parent or guardian and a second device with a child. If the distance between the first and second device exceeds a certain threshold, an alarm will sound or other notification will be sent. See, for example, US Patent Publication Nos. <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>, <CIT>. In some systems (such as <CIT>), the second device is a pressure sensor embedded in a child seat so as to be able to sense a child in the seat. In other examples (such as US Patent Publication Nos. <CIT>, <CIT>), devices can be used to establish the perimeter of a safety zone, so that if a child wearing another device leaves the safety zone, then an alert is initiated.

Other systems have been proposed for monitoring particular objects of value. These systems may work by tracking the device using an attached beacon connected to a telecommunications network, for instance.

Many of the proposed systems require a user to initiate the monitoring. Human error can result in a system not being activated, and so notifications for separation or loss not being generated and received. Moreover, many systems cannot account for safe and permissible situations in which a monitored entity (be it a child or a valuable item) might leave a safety zone - for instance when accompanied by a caretaker. This results in erroneous alerts being sent that are then ignored or are troublesome for the user. Such events reduce a user's willingness to use and activate safety or monitoring systems, and to rely on any notification received.

International Patent Publication No. <CIT> discloses a system for monitoring and signalling comprising at least: one safety device for a vehicle, configured to generate an output signal indicative of the presence of an infant or similar; a first signalling device, coupled to the safety device and configured to emit first signals in sequence when the output signal indicates the presence of the infant in the vehicle; and a second signalling device, couplable to a vehicle and configured to emit second signals in sequence when coupled to the vehicle. The system further comprises a mobile device, configured to: receive pairs of signals each formed by a first and a second signal; determine, for each pair, a first and a second distance; compare the values of the first and the second distance with a first and a second reference distance, respectively; detect, for each received pair of signals, whether the system alternately operates in a proximity condition, a distance condition, a first intermediate condition or a second intermediate condition; and generate, in the event of the detection means detecting the distance condition, different monitoring signals, depending on the fact that the distance condition has been detected after the detection of the first or the second intermediate condition.

International Patent Publication No. <CIT> describes a system having a first object for theft detection of a second object, the second object being in a pair with a third object for securing the second object, the first object comprising: a detector for detecting a second signal of the second object and a third signal of the third object when transmitted within a detection area of the detector, and providing a detector output; a controller for identifying, by processing the detector output, a condition indicating both (i) a pairing of the second signal and the third signal, and (ii) the second signal moving out of the detection area while the third signal is not being detected within the detection area, and performing a theft detection action when the condition is identified.

International Patent Publication No. <CIT> considers an apparatus that send alerts on a distance between items. The apparatus includes a radio for communicating with an internet of things (IoT) tag on an item. A locator module determines a distance between two or more items, and then an alertor module alerts a user to a violation of a proximity rule.

US Patent Publication No. <CIT> considers a system, apparatus, and method of providing an alert when an infant or child is in a child safety seat in a vehicle.

Accordingly, there is a need for an improved separation monitoring system, which addresses the drawbacks of the prior art.

In a first aspect according to the invention there is described a method for indicating excessive separation between a first wireless device and a second wireless device, the method comprising:.

The method indicates excessive separation between a first wireless device and a second wireless device in the context of a first and second zone or region defined around or with respect to a third device (or a plurality of third devices). The first and second zones may represent the same area and have the same boundaries, or may be different areas, having different zone boundaries. The first and second zones will typically be at least partly overlapping. The first zone will include the third wireless device within or on its boundary, such that the first zone extends contiguously from or around the third wireless device. The second zone will include the third wireless device within or on its boundary, such that the second zone extends contiguously from or around the third wireless device. The boundary or perimeter of each of the first or second zone is not necessarily equidistant to the third wireless device at all points on the boundary. However, the boundary or perimeter of each of the first or second zone around the third wireless device may be equidistant, such that the third wireless device is a centre point of the respective zone. The first and second zones are not remote from the third wireless device.

In some contexts, the first device may be a monitored device, which could be associated with a monitored entity such as a child or valuable item. The second device may be a supervisor device, which could be associated with a supervisor or caretaker of the monitored entity such as a parent or guardian. The third device may be a surveillance zone device, which may be associated with, or may define, a first zone in which surveillance of the monitored device takes place, and a second zone in which surveillance of the supervisor device takes place. The surveillance zones could be considered a 'safe space' or 'bubble' within which the monitored device and supervisor device can move freely, providing both the monitored device and supervisor device remain within their respective zone (which may be the same area or zone). The first and second zones (or surveillance zones) can be defined as areas each having a perimeter or boundary a fixed distance around the third device, or could be defined with respect to the third device in another way. More than one third device could be used to define a given surveillance zone and its boundary or perimeter. As noted above, the first zone defined with respect to the third device and relevant to the first wireless device may be the same, or different to the second zone defined with respect to the third device and relevant to the second device. In other words, the first device and the second device may be subject to surveillance zones of different areas and having different boundaries. The first and second surveillance zones may be entirely different, may be overlapping, or may be the same. In one example, the first surveillance zone (first zone) is a smaller area than the second surveillance zone (second zone), the first zone being entirely within the second zone.

The method monitors the spacing or separation between the first device and the third device, and between the second device and the third device. The monitoring describes receiving or obtaining any indicator of the relative position of the given devices. The indicator may simply be the receipt (or lack of receipt) of a wireless transmission between two devices. Alternatively, the indicator could be a measure of the distance between devices, or a measure of a parameter that is related to the distance between devices in a predictable manner (signal strength, for instance).

The method determines whether the supervisor device and monitored device are both within their respective surveillance zone defined with respect to the surveillance zone device. In particular, the method determines if the monitored device is inside the first surveillance zone, whilst the supervisor device is outside of the second surveillance zone. This could indicate, for instance, that the monitored entity associated with the monitored device might be unsupervised. The determination of the presence or absence of the monitored device and/or supervisor device inside their surveillance zones can be made in a number of ways, as discussed below. In one example, the presence or absence of the monitored device and/or supervisor device inside their respective surveillance zones can be indicated by whether a wireless connection (via a specific wireless technology) can be made between the first device (monitored device) and the third device (the surveillance zone device) and/or between the second device (the supervisor device) and the third device (the surveillance zone device). In an alternative example, the presence or absence of the monitored device and/or supervisor device inside their respective surveillance zone can be indicated by obtaining a measure or indication of the separation between the first device (monitored device) and the third device (the surveillance zone device) and between the second device (the supervisor device) and the third device (the surveillance zone device).

The first, second and third device are each wireless devices. Wireless devices are devices that can communicate, at least with each other, via wireless means. The wireless devices may be connected to a telecommunications network through a telecommunications infrastructure, or could communicate with each other directly via wireless technologies including WiFiRTM, BluetoothRTM or ultra-wide-band. The devices may be mobile devices, such as a mobile telephone, smartphone or tablet, or may be another portable or wearable device, including but not limited to a smart watch or a wireless communications beacon within a necklace or bracelet. The devices may be incorporated or embedded in another item, including a car seat, child car seat, car navigation system, or an item of clothing.

The alert may be any type of alarm or notification. For example, the alert may be the sounding of an alarm at the first, second or third device, or at another device associated with one or more of the devices. Alternatively, the alert could be a notification message sent to one or more of the first, second or third device, or another device associated with one of the devices. The alert could be a voice call or automated audible message sent to one or more of the first, second or third device, or another device associated with one of the devices. Other actions may be initiated together with the alert, including unlocking of a vehicle associated with the third device (surveillance zone device) or activation of climate control in a vehicle associated with the third device (surveillance zone device).

The method may be used in various scenarios. Example scenarios are provided herein, which are not intended to be limiting. In a first example, the monitored device is associated with an entity such as a child (for instance, as part of a wearable item worn by the child). The supervisor device is associated with a parent or guardian of the child (for instance, the smartphone belonging to the parent or guardian). The surveillance zone device is associated with a surveilled area, such as the interior of a vehicle (for instance, being part of the vehicle anti-theft system or navigation system). In this example, the method may be used to prevent forgotten baby syndrome, such that an alert is sent (perhaps to the supervisor device) in the event that the monitored device (associated with the child) remains within a first surveillance zone (within the car interior) whilst the supervisor device (associated with the parent or guardian) is determined to have left a second surveillance zone (being the same as the first surveillance zone, or being a zone that has a slightly larger area and having its boundary a short distance (i.e. <NUM> metre) from the car interior).

In a further example, the first and second surveillance zones could be defined around a third device which is attachable by a user to a fixed point (such as a beach umbrella on a beach). The monitored device may be associated with, or attached to, a valuable item such as a wallet. The supervisor device may be associated with the owner of the monitored device (for example, being the smartphone of the owner of the monitored entity).

Preferably, prior to the monitoring step, the method further comprises:.

Preferably, the set of conditions is a first set of conditions, the method further comprises:.

Optionally, the set of conditions may be a first set of conditions, and the method may further comprise:.

Preferably, wherein if the conditions for initiating an alert are met, then prior to initiating the alert, the method further comprises:.

Preferably, the set of conditions is a first set of conditions, and the method further comprises:.

Under the fourth set of conditions, the alert is initiated if both the first device (monitored device) and the second device (supervisor device) have left their respective surveillance zones, and in addition, the separation between the first device (monitored device) and the second device (supervisor device) suggests that the first and second device have not left their respective surveillance zones together.

The separation of the first wireless device (monitored device) and the second wireless device (supervisor device) is considered in relation to a third zone defined with respect to the second wireless device. The third zone extends contiguously from the second wireless device, so the second wireless device is within or on the boundary of the third zone. The third zone is not remote from the second wireless device. The boundary or perimeter of the third zone is not necessarily equidistant to the second wireless device at all points on the boundary. However, the boundary or perimeter of the third zone around the second wireless device may be equidistant, such that the second wireless device is a centre point of the third zone.

Preferably, the method further comprises:.

Whether a set of conditions has been met depends on the separation between the first, second and/or third devices. Any measure indicative of the extent of separation could be used. In one example, the extent of separation could be indicated by whether a wireless connection is made between two devices (in other words, whether the devices are within the each other's wireless range). In another example, a distance (or an indication of distance, such as signal power) is used as a measurement or indication of the separation between two of the devices, and this is then compared to a threshold to determine if the device is within its zone and so the prescribed conditions are met.

Preferably, the first wireless device being inside the first zone defined with respect to the third wireless device comprises the first wireless device and the third wireless device being wirelessly connected;.

Preferably, determining whether a set of conditions is met comprises determining whether the first wireless device and the third wireless device are wirelessly connected, and/or determining whether the second wireless device and the third wireless device are wirelessly connected, and/or determining whether the first wireless device and the second wireless device are wirelessly connected. In other words, prior to determining whether a set of conditions are met, the method may determine whether two of the first, second or third device are wirelessly connected.

Preferably, the wireless connection is a connection via Wi-Fi, Bluetooth, ultra-wide-band technologies, or any other type of wireless communications technology or wireless telecommunication mechanism. Optionally, the wireless communications technology has a reception range, defining an area in which the wireless connection can be made around the device.

Preferably, the first wireless device being inside the first zone defined with respect to the third wireless device comprises the first wireless device and the third wireless device being spaced apart by at most a first threshold separation;.

The separation may be any indication of the extent of separation, including a measurement of the distance between two devices, or another indicator related to the distance (such as the strength of a signal passed between two devices). The threshold separation will be a threshold associated with the type of indication of the extent of separation that is determined.

Preferably, the method may further comprise:.

Preferably, the first wireless device, the second wireless device and/or third wireless device are connected to a telecommunications network, and determining whether a set of conditions is met comprises the telecommunications network comparing location data for the first wireless device, the second wireless device and/or the third wireless device. In one example, the devices are connected to a telecommunications network, and the separation can be determined by the telecommunications network identifying the location of each device and so determining the distance between devices. The determination of the separation may take place at an entity or controller within the network, or a group of entities within the network, and then transmitted or sent to one of the first, second or third devices, or a controller associated with and/or local to the first, second or third devices. The step of determining whether the conditions are met could take place at the network entity in the telecommunications network, or at the controller associated with and/or local to the first, second or third device.

Preferably, one of the first wireless device, second wireless device and/or third wireless device is connected to a telecommunications network, and initiating the alert comprises sending an alert message via the telecommunications network to at least one of the first wireless device, the second wireless device and/or the third wireless device. The alert may be an SMS or IMS message, or another notification sent via the telecommunications network. In another example, initiating an alert may further comprise sending an alert message via the telecommunications network to a further device that is not the first, second or third wireless device.

Preferably, at least one of the first wireless device, second wireless device and/or third wireless device comprises a transceiver, and initiating the alert comprises one of the first, second or third wireless device sending an alert message to at least one other of the first, second or third wireless device. In one example, the alert message could be made directly via a wireless communications technology such as WiFi, Bluetooth, or ultra-wide-band.

Preferably, initiating an alert comprises activating an alarm or sending a notification. The alarm may be sounded at one or more of the first, second or third wireless device. The alarm may be sounded at another entity directly connected to one or more of the first, second or third wireless device, or connected via a telecommunications network. Initiating an alert may comprise sending a message or notification to any one of the first, second, or third wireless device, or another device. Initiating an alert may also comprise other actions, including activating air conditioning within a surveillance zone associated with the third device (such as the first or second zone), unlocking access doors to allow access to a surveillance zone (for example, where the method is used to prevent forgotten child syndrome), or locking access doors to prevent access to a zone (for example, where the method is used to prevent theft of an unattended valuable object).

Preferably, each of the first, second and third device comprise a transceiver. Each of the first second or third device may be a mobile device, beacon for wireless communication, tablet or other wireless device.

Preferably, the second wireless device comprises a plurality of second wireless devices, and wherein the step of determining whether a set of conditions is met comprises determining whether the set of conditions is met for each one of the plurality of second wireless devices; and
wherein if the set of conditions is met for every second wireless device of the plurality of second wireless devices, then initiating the alert. In other words, there may be two or more second devices (supervisor devices). If at least one of the second devices remains within the second surveillance zone together with the first device (monitored device) remaining in the first surveillance zone, then no alert is initiated. However, if all the second devices (supervisor devices) move outside of their surveillance zone whilst the first device (monitored device) stays within their zone, then an alert is initiated. In some scenarios, this set of conditions could indicate that the monitored device has been left unattended in its surveillance zone by all of the attendant caretakers associated with a supervisor device.

Preferably, the first wireless device comprises a plurality of first wireless devices, and wherein the step of determining whether a set of conditions is met comprises determining whether the set of conditions is met for each one of the plurality of first wireless devices; and
wherein if the set of conditions is met for any one first wireless device of the plurality of first wireless devices, then initiating the alert. In other words, there may be more than one first device (monitored device). For instance, there may be two or more monitored devices, each monitored device associated with a different monitored entity (such as a different child). In this case, if any one of the first devices (monitored devices) leaves the first surveillance zone whilst the second device(s) (supervisor device(s)) remain within the second surveillance zone, then an alert may be issued. In another example, an alert may be issued if any one first device (monitored device) is outside of the first surveillance zone whilst also being separated from any one second device (supervisor device) by more than a threshold separation.

Optionally, a plurality of first wireless devices and a plurality of second wireless devices may be used.

Optionally, the first surveillance zone is the same as or overlapping with the second surveillance zone. Optionally, the first surveillance zone is entirely inside (or concentric with) the second surveillance zone. Optionally, at least the third device is located within both the first and the second surveillance zone.

The characteristics of features discussed above with respect to the method will also apply to any corresponding feature discussed below in respect of a controller or a system.

In a second aspect related to the invention there is a controller or a controlling apparatus for controlling a system for indicating excessive separation between a first wireless device and a second wireless device, the controller in communication with the first wireless device, the second wireless device and a third wireless device, wherein the controller or controlling apparatus is configured to:.

In some examples, the first wireless device is a monitored device, associated with a monitored entity. The second wireless device may be a supervisor device, associated with a supervisor or guardian of the monitored device. The third wireless device may be a surveillance zone device, which is associated with a first and second surveillance zone. The surveillance zones may be areas or regions defined with respect to the third wireless device. The first zone defined for the first device may be different in size (and/or shape) than compared to the second zone defined for the second device. The zones may be defined by a threshold distance, or may be determined by the presence or absence of a wireless connection between the given devices. An alert may be initiated if the monitored device is within its surveillance zone, whilst the supervisor device is outside of its surveillance zone.

Preferably, the controlling apparatus is configured to:.

Preferably, the set of conditions is a first set of conditions, and the controlling apparatus is further configured to:.

Preferably, the controlling apparatus is further configured to:.

Various measures could be used to determine whether the first wireless device is within a first zone defined with respect to a third wireless device, whether the second wireless device is within a second zone defined with respect to a third wireless device, or whether the first wireless device is within a third zone defined with respect to a second wireless device. In some examples, this could be indicated by the presence or absence of a wireless connection between the given pairs of devices, wherein the zones relate to regions of wireless reception or coverage. In other examples, the controller may obtain an indication of the separation between the given devices (which could be a measure of distance, or another related indicator that is proportional to the distance) and then compare this to a threshold value associated with the separation. In this example, a threshold defines the boundary of a given surveillance zone.

Preferably, the controlling apparatus being configured to determine whether a set of conditions is met comprises the controlling apparatus being configured to determine whether the first wireless device and the third wireless device are wirelessly connected, and/or the controller being configured to determine whether the second wireless device and the third wireless device are wirelessly connected, and/or the controller being configured to determine whether the first wireless device and the second wireless device are wirelessly connected.

Preferably, the wireless connection is a connection via Wi-Fi, Bluetooth, ultra-wide-band technologies, or any other wireless communications technology. Optionally, the wireless communications technology at a given device will have a range of reception, which would in turn define the respective zone.

Preferably, the method is further configured to:.

Preferably, the first wireless device, the second wireless device and/or the third wireless device are connected to a telecommunications network, and the controlling apparatus being configured to determine whether a set of conditions is met comprises the telecommunications network comparing location data for the first wireless device, the second wireless device and/or third wireless device and receiving the results of this comparison at the controlling apparatus.

Preferably, one of the first wireless device, second wireless device and/or third wireless device is connected to a telecommunications network, and the controlling apparatus being configured to initiate the alert comprises the controlling apparatus causing transmission of an alert message via the telecommunications network to at least one of the first wireless device, the second wireless device and/or the third wireless device.

Preferably, at least one of the first wireless device, the second wireless device and/or the third wireless device comprises a transceiver, and the controlling apparatus being configured to initiate the alert comprises the controlling apparatus causing transmission of an alert message to at least one other of the first, the second or the third wireless device.

Preferably, the second wireless device comprises a plurality of second wireless devices, and wherein the controlling apparatus being configured to determine whether a set of conditions is met comprises the controlling apparatus being configured to determine whether the set of conditions is met for each one of the plurality of second wireless devices; and
wherein if the set of conditions is met for every second wireless device of the plurality of second wireless devices, then the controlling apparatus is configured to initiate the alert. In other words, there are two or more second devices (supervisor devices), and an alert is raised if every one of the second devices (supervisor devices) is determined to be outside of the second zone defined with respect to the third device, whilst the first device (monitored device) remains within the first zone.

Preferably, the first wireless device comprises a plurality of first wireless devices, and wherein the step of determining whether a set of conditions is met comprises determining whether the set of conditions is met for each one of the plurality of first wireless devices; and
wherein if the set of conditions is met for any one first wireless device of the plurality of first wireless devices, then initiating the alert. In other words, there are two or more first devices (monitored devices), and an alert is raised if any one of the first devices (monitored devices) is determined to be outside of the first zone defined with respect to the third device, whist the second device(s) (monitored device(s)) is determined to be within the second zone.

As will be understood by the skilled person, any number of first devices and supervisor devices could be used.

Optionally, the controlling apparatus is configured to initiate the alert comprises the controlling apparatus being configure to activate an alarm or send a notification. The controlling apparatus may activate or initiate an alarm at one or more of the first, second or third device, or at another device.

Optionally, the controlling apparatus is integral to one of the first device (monitored device), second device (supervisor device) or third device (the surveillance zone device), or is a stand-alone entity. The controlling apparatus could be located at a telecommunication network entity and connected to the first, the second and the third device via a telecommunications network. The controlling apparatus may be a single network entity, or a group of network entities performing the described functions of the controlling apparatus.

In a third aspect according to the invention there is a system for indicating excessive separation between a first wireless device and a second wireless device, comprising:.

Preferably, the controlling apparatus is integrated into one of the first, second or third wireless device, or is a stand-alone entity.

Preferably, the first, second or third wireless device each comprise any one of: a mobile telecommunications wireless device, a wearable wireless device, a wireless device embedded into another item, a wireless communications beacon.

The first, second and third wireless device may comprise a transceiver, with means for communication by wireless technologies. The first wireless device, the second wireless device, and the third wireless device may be any type of device that allows wireless communication, at least with devices within a certain proximity of each other. Optionally, the first, second and third wireless device (which may be the monitored, the supervisor, and the surveillance zone device, respectively) are each any one of: a mobile device, a wearable device, a device embedded into another entity. For instance the first, second or third wireless device could be embedded into a vehicle navigation or anti-theft system, or embedded into a child car seat.

In a fourth non-claimed aspect there is a computer-readable medium carrying a computer program comprising program instructions that, when executed on a computer cause the computer to perform the method as described above. For example, the computer program, when executed on a mobile device, may comprise an application for carrying out the described method.

The disclosure will now be put into practice in a number of ways, and preferred embodiments will now be described by way of example only and with reference to the accompanying drawings, in which:.

In the drawings, like parts are denoted by like reference numerals. The drawings are not drawn to scale.

<FIG> shows a system comprising a first wireless device <NUM>, a second wireless device <NUM>, a third wireless device <NUM> and a controller (or controlling apparatus) <NUM>. At least the first <NUM> and third <NUM>, and the second <NUM> and third <NUM> wireless devices are capable of wireless communication with each other. The controller <NUM> is in communication with all of the first <NUM>, second <NUM> and third <NUM> wireless devices. In certain examples, the first wireless device <NUM> may be considered or denoted a monitored device (M), associated with a monitored entity, the second wireless device <NUM> may be considered or denoted a supervisor device (S), associated with a caretaker or guardian of the monitored entity, and the third wireless device <NUM> may be considered or denoted a surveillance zone device (Z) for defining a surveillance zone. This denotation is used within the description of the illustrative examples of the invention, as described below.

In the system of <FIG>, the controller <NUM> is integrated or embedded within the surveillance zone device <NUM>. Both the supervisor device <NUM> and the monitored device <NUM> are each in communication with the controller <NUM> at the surveillance zone device <NUM>.

Each of the monitored device <NUM>, supervisor device <NUM> and surveillance zone device <NUM> are wireless devices and comprise a transceiver. The devices may be a mobile device (such as a smartphone or tablet), or may be a wearable device having a wireless beacon (such as a smart watch, smart bracelet or smart dongle). The devices (in particular the monitored device <NUM>) may be embedded in an item of clothing, or another item (such as a child seat). The device (in particular the surveillance zone device <NUM>) could be embedded in another piece of hardware (such as a vehicle navigation system, vehicle alarm system or another item within a vehicle control system). The devices may communicate with each other using any suitable wireless telecommunications technologies, or a mix of wireless telecommunications technologies, including but not limited to Bluetooth™, ultra-wide-broad and Wi-fi™,.

The supervisor device <NUM> is intended to be carried by a guardian or caretaker of a monitored entity. The supervisor device <NUM> is configured to transmit or receive an identification signal that, after evaluation by the surveillance zone device <NUM>, will allow the controller to determine or obtain information on the presence or absence of the supervisor device in a surveillance zone, to provide information on the proximity of the supervisor device to the surveillance zone device <NUM> and/or to the monitored device <NUM>. The supervisor device <NUM> may be a stand-alone device (such as a wireless communication beacon, for instance a Bluetooth or ultra-wide bandwidth beacon) or it may be a function performed by the guardian or caretaker's smartphone or mobile device (used as a wireless communication beacon, for instance a Wi-fi™, Bluetooth or ultra-wide bandwidth beacon controlled by a specific application at the mobile device).

The monitored device <NUM> is configured to be carried by or associated with the monitored entity, such as an individual (or object) that requires supervision. The monitored device <NUM> is configured to transmit an identification signal that, after evaluation by the surveillance zone device <NUM> (and/or, in other examples, by the supervisor device <NUM>), will allow the controller to obtain notification or information of the monitored device's presence within a surveillance zone, and/or determine its proximity to other devices. The monitored device may be a wireless communication beacon, for instance a Wi-fiRTM , BluetoothRTM or ultra-wide-band beacon.

The surveillance zone device <NUM> can be positioned in a location or area at which monitoring is required (for example, in a vehicle) in order to establish one or more surveillance zones or "safety bubbles" for the monitored <NUM> and supervisor <NUM> devices. The surveillance zone device <NUM> is configured to determine the virtual perimeter of the surveillance zones. The surveillance zone device <NUM> may be a stand-alone device (for example, wireless communications beacon, such as a Bluetooth, Wi-fi™ or ultra-wide-band beacon) or could be integrated with other hardware (such as a vehicle's anti-theft alarm or telematics box in the illustrative example).

The controller <NUM> comprises a processor, configured to acquire, obtain or determine information on the proximity of each of the supervisor device <NUM>, the monitored device <NUM> and the surveillance zone device <NUM> to each other. The controller may receive information on whether a wireless connection is made between any two of the monitored device <NUM>, the supervisor device <NUM> and the surveillance zone device <NUM>. In addition, the controller <NUM> may calculate separations based on parameters provided by each device, or may be provided with relevant values directly by the devices. The controller <NUM> may receive a parameter other than a location or a measure of distance to determine an extent of separation, for instance a measure that has a known relationship with distance (such as signal strength), in order to determine the separation between devices. The controller <NUM> is also configured to process the obtained or determined information, in order to determine if certain conditions are met. If certain conditions are met, the controller may generate an alert (for example, sound an alarm or send a mobile phone notification) and/or may initiate another action (for instance, unlocking of the doors or turning on temperature controls within the surveillance zone).

Methods according to the flow diagrams shown at <FIG> and <FIG> can be implemented at the system of <FIG>. In one illustrative example that is not intended to be limiting, the methods of <FIG> and <FIG> can be used to monitor whether a supervisor device <NUM> (associated with a guardian or caretaker, such as a parent) leaves a surveillance zone, whilst a monitored device <NUM> (associated with a monitored entity, such as a child) remains inside the surveillance zone. The described example method may be particularly useful for preventing forgotten baby syndrome - where a baby or toddler is inadvertently left in a vehicle by a carer or guardian.

Referring to the method of <FIG>, initially the system is idle <NUM>. The surveillance zone device <NUM> may make a wireless connection <NUM> (and subsequently lose a connection <NUM>) with the supervisor device <NUM> only, and still remain in the idle mode <NUM>.

In the method according to <FIG>, a wireless connection may be considered to have been made if a wireless connection of a particular type (for instance including but not limited to Bluetooth, WiFi and ultra-broad-band) is established that is capable for use in communication or exchange of information. It will be understood that for a given wireless technology and device, there will be a signal range inside of which connection can be made to the device, but outside of which a connection to the device will not be made. As such, the establishment of a connection can provide an indication of proximity between two devices. As an example, if a wireless connection is determined to have been made between the supervisor device <NUM> and the surveillance zone device <NUM>, then the supervisor device <NUM> is considered to be inside its surveillance zone defined with respect to the surveillance zone device <NUM>, but if a wireless connection is not made between these two devices, then the supervisor device <NUM> is considered to be outside its surveillance zone. Thus, the establishment or otherwise of a wireless connection provides a binary (inside/outside) indication of whether a device (in this example, the supervisor device <NUM>) is in its surveillance zone defined with respect to the surveillance zone device <NUM>.

If the surveillance zone device <NUM> makes a wireless connection (according to the description above) to both the supervisor device <NUM> and to the monitored device <NUM> simultaneously <NUM>, then the system switches to a monitoring mode <NUM>. For instance, when the monitored device <NUM> and the supervisor device <NUM> each move within signal range of the surveillance zone device <NUM> then a wireless connection is made. In the illustrative example where the surveillance zone (for both the monitored device <NUM> and supervisor device <NUM>) is within a vehicle, then this indicates the parent or guardian associated with a supervisor device <NUM> and a child associated with a monitored device <NUM> have entered the vehicle. Thus monitoring should begin.

The system continues in the monitoring state <NUM> until or unless further conditions are met. The system remains in the monitoring state <NUM> whilst both the supervisor device <NUM> and the monitored device <NUM> are within their surveillance zones, and so a wireless connection between each of these devices and the surveillance zone device is maintained. In the monitoring state <NUM> the system periodically confirms that the surveillance zone device <NUM> and the supervisor device <NUM>, and the surveillance zone device <NUM> and the monitored device <NUM>, are wirelessly connected. Although periodic determination of these parameters may also take place in the idle mode <NUM>, the period of time between each determination in the idle mode <NUM> will be less than in the monitoring mode <NUM> (such that much more frequent determinations are made in the monitoring mode <NUM>).

If, in the monitoring mode <NUM>, a wireless connection between the monitored device <NUM> and the surveillance zone device <NUM> is lost <NUM>, or if the connection between the surveillance zone device <NUM> and both of the monitored device <NUM> and the supervisor device <NUM> are lost <NUM>, then the system returns to the idle state <NUM>. For instance in the illustrative example where the surveillance zone is within a vehicle, these conditions assume that either the monitored device <NUM> (associated with a child) or the supervisor device <NUM> and the monitored device <NUM> (associated with the guardian and the child, respectively) have exited the vehicle. Therefore, safety related to the child being left in the vehicle is no longer of concern, and so monitoring is no longer required.

However, in the event that the surveillance zone device <NUM> loses wireless connection with the supervisor device <NUM> (whilst maintaining connection with the monitored device <NUM>) <NUM>, the system moves to a pre-alert state <NUM>. According to the illustrative example, in this case the supervisor device <NUM> (for instance, associated with the parent or guardian) may have moved out of the surveillance zone whilst leaving the monitored device <NUM> (for instance, associated with the child) is still within the surveillance zone. As such, this set of conditions could indicate that a parent or guardian has left the child in the vehicle unattended.

The pre-alert state <NUM> is a state activated in the system prior to an alert being sent. Activation of a pre-alert state <NUM> begins a short, predefined time interval t. During the pre-alert state <NUM> the system continues to monitor the separation of the supervisor device <NUM> and the monitored device <NUM> to the surveillance zone device <NUM> by determining whether a wireless connection is made between the surveillance zone device <NUM> and each of the monitored <NUM> and supervisor <NUM> devices. During the predefined time interval, t, the presence or absence of a connection may be determined more frequently than during the monitoring state <NUM>, or at the same frequency (or simply at the beginning and end of the predefined time interval, t, only).

The use of the pre-alert state <NUM> avoids excessive false alerts, as it allows determination whether the supervisor device <NUM> has left its surveillance zone for a sustained period of time. The predefined time interval t must therefore be chosen appropriately, so as to minimise false alerts, but without leaving the monitored device <NUM> (and associated child or other entity) alone in its surveillance zone for too extended a period. In some examples, the predefined time interval t may be <NUM> seconds, <NUM> seconds, <NUM> seconds, <NUM> seconds, <NUM> seconds or <NUM> seconds.

If the conditions for alert are maintained after elapse of the predefined time interval, t, <NUM> then an alert is initiated. An alert <NUM> that is initiated may take various forms. In the present example, the alert <NUM> is a notification (such as a screen notification or text-based message via IMS or SMS) to the supervisor device <NUM>. In alternative examples, the alert could be a telephone call, screen notification or text-based message to a nominated smartphone or other mobile device (and which is not necessarily the same as the supervisor device <NUM>). In further examples, the system could instead or additionally activate an alarm at the surveillance zone device <NUM> (which could be connected to a vehicle alarm, for instance). The alert could further initiate other actions, for instance unlocking access to a surveillance zone (i.e. unlocking a vehicle) or turning on air conditioning or temperature controls in a surveillance zone.

Finally, if the system in the idle state <NUM> makes a wireless connection with the monitored device <NUM> and the surveillance zone device <NUM> (without also making a wireless connection between the supervisor device <NUM> and the surveillance zone device <NUM>) <NUM> then the system is moved directly to the pre-alert state <NUM>. For instance, according to the illustrative example this could indicate that a child associated with the monitored device <NUM> has been placed in the vehicle by a person not associated with the supervisor device <NUM>, so the child appears to be left unattended.

A second example of a method that can be implemented at the system of <FIG> is shown in <FIG>. Referring to the method of <FIG>, initially the system is idle <NUM>. The surveillance zone device <NUM> may make a connection <NUM> (and subsequently lose a connection <NUM>) with the supervisor device <NUM> only, but remain in the idle mode <NUM>. In this second example of the method, a connection is considered to have been made if the extent of separation (shown in <FIG> as d(SZ)) between the supervisor device <NUM> and the surveillance zone device <NUM> is determined at the controller to be less than or equal to a first threshold T<NUM>. For instance, according to the previous illustrative example this indicates that a guardian associated with the supervisor device <NUM> has entered a surveillance zone set within the interior of a vehicle and defined with respect to the surveillance zone device <NUM>.

In the present example, the separation is measured or determined as a distance and the first threshold T<NUM> is a first threshold distance. However, the separation could be any measure indicative of the spacing between the supervisor device <NUM> and the surveillance zone device <NUM> (such as a measurement of signal strength, which is related to distance). The measure of separation can be determined by parameters obtainable via any wireless communication technologies, for instance Bluetooth, ultra-wide-band or WiFi.

If the surveillance zone device <NUM> makes a connection to both the supervisor device <NUM> and to the monitored device <NUM>, then the system switches to a monitoring mode <NUM>. In this second example of the method, this means that the monitoring mode is initiated <NUM> when the separation between the supervisor device <NUM> and the surveillance zone device <NUM> (shown in <FIG> as d(SZ)) is determined at the controller to be less than or equal to a first threshold T<NUM>, as well as the separation between the monitored device <NUM> and the surveillance zone device <NUM> (shown in <FIG> as d(MZ)) is determined at the controller to be less than or equal to a second threshold T<NUM>. Again, the separations d(SZ) and d(MZ) are distances obtainable via wireless technologies (although other indications for the amount of separation could be used), and the first threshold T<NUM> and second threshold T<NUM> are threshold distances. The first threshold T<NUM> and second threshold T<NUM> may be the same, or different. In the previous illustrative example, this set of conditions might be met if a parent (carrying the supervisor device <NUM>) and a child (carrying, wearing or associated with the monitored device <NUM>) enter a surveillance zone defined within a vehicle interior with respect to the surveillance zone device. Thus, the monitoring state <NUM> is initialised.

The system continues in the monitoring state <NUM> until further conditions are met. In particular, if connection with the monitored device <NUM> is lost <NUM>, or if the connections with the monitored device <NUM> and with the supervisor device <NUM> are lost <NUM>, then the system returns to the idle state <NUM>. In practice, the loss of connection with a device is measured according to the separation between either the supervisor device <NUM> or monitored device <NUM> and the surveillance zone device <NUM> and comparison with a respective threshold distance. More specifically, the system returns to an idle mode <NUM> from the monitoring mode <NUM> when the separation between the monitored device <NUM> and the surveillance zone device <NUM> (shown in <FIG> as d(MZ)) is determined at the controller to be less than or equal to a second threshold T<NUM>, or that the separation between the monitored device <NUM> and the surveillance zone device <NUM> (shown in <FIG> as d(MZ)) is determined at the controller to be less than or equal to a second threshold T<NUM>, as well as the separation between the supervisor device <NUM> and the surveillance zone device <NUM> (shown in <FIG> as d(SZ)) is determined at the controller to be less than or equal to a first threshold T<NUM>. Again, in this example the separation d(MZ) and d(SZ) are distances and the first threshold T<NUM> and second threshold T<NUM> are threshold distances.

Thus, the system remains in the monitoring state <NUM> whilst both the supervisor device <NUM> and the monitored device <NUM> are within their respective surveillance zones. In the monitoring state <NUM> the system periodically determines the separation between the surveillance zone device <NUM> and the supervisor device <NUM>, and between the surveillance zone device <NUM> and the monitored device <NUM>. Although periodic determination of these parameters may also take place in the idle mode <NUM>, the period of time between measurements of the separation will be less in the monitoring mode <NUM> (such that much more frequent determinations are made in the monitoring mode <NUM> than the idle mode <NUM>).

In the event that the surveillance zone device <NUM> loses connection <NUM> with the supervisor device <NUM> (whilst maintaining connection with the monitored device <NUM>), the system moves to the pre-alert state <NUM> (as described in more detail above). In practice, the surveillance zone device <NUM> is considered to lose connection <NUM> with the supervisor device <NUM> when it is determined that the separation between the supervisor device <NUM> and the surveillance zone device <NUM> is greater than the first threshold T<NUM>. As before, the extent of separation in this case is a measure of the distance d(SZ) between the supervisor device <NUM> and the surveillance zone device <NUM>, and the first threshold T<NUM> is a first threshold distance. According to the illustrative example, this set of conditions would align with the supervisor device <NUM> (for instance, associated with a guardian) leaving the surveillance zone (for instance the interior of a vehicle) whilst the monitored device <NUM> (for instance, associated with a child) is still within the surveillance zone. Therefore this set of conditions could indicate that a parent or guardian has left the child in the vehicle unattended.

When in the pre-alert state <NUM>, at the end of the predefined time interval t <NUM>, the extent of separation d(SZ) between the supervisor device <NUM> and the surveillance zone device <NUM>, and the extent of separation d(MZ) between the monitored device <NUM> and the surveillance zone device <NUM>, is determined once again. If the extent of separation d(SZ) between the supervisor device <NUM> and the surveillance zone device <NUM> is still greater than the first threshold T<NUM>, and also the extent of separation d(MZ) between the monitored device <NUM> and the surveillance zone device <NUM> is still less than or equal to the second threshold T<NUM>, an alert <NUM> is initiated. In the illustrative example, this could indicate that the child associated with the monitored device <NUM> has been left in the surveillance zone (i.e. within a vehicle), whilst the parent or guardian associated with the supervisor device <NUM> has left the surveillance zone (in other words, has left the vehicle). As described above, the alert <NUM> that is initiated may take various forms. In the present example, the alert <NUM> is a notification (such as a screen notification or text-based message via IMS or SMS) to the supervisor device <NUM>.

It is noted that if during or at the end of the pre-alert phase <NUM> the extent of separation of the supervisor device <NUM> and the surveillance zone device <NUM> is determined to have returned to less than or equal to the first threshold T<NUM>, then the pre-alert state <NUM> is deactivated <NUM>, and the system returns to a monitoring state <NUM>. For instance, in the illustrative example this could occur if the parent or guardian carrying the supervisor device <NUM> has returned to a vehicle comprising the surveillance zone defined with respect to the surveillance zone device <NUM>.

In addition, if during or at the end of the pre-alert phase <NUM> the extent of separation d(MZ) of the monitored device <NUM> and the surveillance zone device <NUM> is determined to exceed the second threshold T<NUM>, then the system is returned <NUM> to the idle state <NUM>. For instance, in the illustrative example this could indicate that the child associated with monitored device <NUM> has been removed from the vehicle during the predefined time interval t associated with the pre-alert stage <NUM>.

Finally, if the system in the idle state <NUM> identifies the extent of separation d(MZ) of the monitored device <NUM> and the surveillance zone device <NUM> is less than or equal to the second threshold T<NUM> (whilst the extent of separation d(SZ) of the supervisor device <NUM> and the surveillance zone device <NUM> is also greater than the first threshold T<NUM>) then the system is moved directly to the pre-alert state <NUM>. According to the illustrative example, this could occur if a child associated with the monitored device <NUM> has been placed in the vehicle by a person not associated with the supervisor device <NUM>, so the child appears to be left unattended.

As discussed above, the system and method considered in relation to <FIG>, <FIG> and <FIG> could be implemented as a safety system to prevent leaving an unattended child in a vehicle. In this scenario, the surveillance zone device <NUM> may be installed at the vehicle dashboard, and in some circumstances may be incorporated into the vehicle's own software. <FIG> shows two configurations when the system is used to improve the safety of a child transported in a vehicle.

In <FIG>, the separation (distance d(SZ)) between the supervisor device <NUM> and the surveillance zone device <NUM> is less than or equal to a first threshold, T<NUM>. The separation (distance d(MZ)) between the monitored device <NUM> and the surveillance zone device <NUM> is also less than or equal to a second threshold, T<NUM>. In other words, both the parent and child have entered and are inside a vehicle <NUM> housing the majority of their respective surveillance zones, defined with respect to surveillance zone <NUM>. In view of this, the system has automatically been moved to a monitoring state <NUM>, although a pre-alert state <NUM> has not be triggered.

In <FIG>, the separation (distance d(SZ)) between the supervisor device <NUM> and the surveillance zone device <NUM> is greater than the first threshold, T<NUM>. However, the separation (distance d(MZ)) between the monitored device <NUM> and the surveillance zone device <NUM> remains less than or equal to the second threshold, T<NUM>. Under these conditions , the system is moved to a pre-alert state <NUM> when it is first determined that the distance d(SZ) between the supervisor device <NUM> and the surveillance zone device <NUM> is more than the first threshold, T<NUM>. If these conditions continue after a predefined time interval t, then an alert <NUM> will be issued. These conditions could align with the parent or guardian associated with the supervisor device <NUM> having exited their surveillance zone associated with the vehicle <NUM>, leaving the child (associated with monitored device <NUM>) inside.

<FIG> shows an alternative example of a system for monitoring excessive separation between a second and third device. <FIG> shows a system comprising a first wireless device <NUM>, a second wireless device <NUM>, a third wireless device <NUM> and a controller (or controlling apparatus) <NUM>. Once again, in certain examples, the first wireless device <NUM> may be considered or denoted a monitored device, M, associated with a monitored entity. The second wireless device <NUM> may be considered or denoted a supervisor device, S, associated with the caretaker or guardian of the monitored entity. The third wireless device <NUM> may be considered or denoted a surveillance zone device, Z, around which a surveillance zone is defined. Again, this denotation is used within the description of the system and method below.

In the system of <FIG> the controller <NUM> is configured to control the described system (and to perform the described method) and is integrated into the supervisor device <NUM>. For instance, the supervisor device <NUM> could be a smartphone, executing an application at the control unit of the smartphone. The supervisor device <NUM> and the monitored device <NUM> are each in wireless communication with the surveillance zone device <NUM>, and furthermore are in wireless communication with each other. Wireless communication may take place via any wireless technology, or by different wireless technology between pairs of devices.

Various illustrative real world applications of the system of <FIG> can be envisaged, In one illustrative example, the system can be used to improve the safety of a child within a vehicle, in particular for prevention of forgotten baby syndrome. For instance, just as in the illustrative example discussed above with respect to <FIG>, the surveillance zone device <NUM> may be mounted within the vehicle or form part of the car control system of anti-theft alarm, the supervisor unit <NUM> could be incorporated into a mobile device (such as a smartphone or tablet) carried by a parent or guardian, and the monitored device <NUM> could be a wearable beacon worn or associated with the child. Alternatively the system could be used in any other application where a supervisor or guardian wishes to define a surveillance zone, and to monitor their separation from a monitored entity (such as a child or a valuable item) within the surveillance zone. For the sake of clarity in the description of the system and method of <FIG>, <FIG> and <FIG>, the system and method will be discussed with reference to an illustrative example application in which the surveillance zone device <NUM> is attached to a beach umbrella, to set up a surveillance zone for the monitored device <NUM> (and the supervisor device <NUM>) around the beach umbrella. In the illustrative example the supervisor device <NUM> is associated with a parent or guardian who wishes to supervise or monitor a child (primarily in the surveillance zone) associated with the monitored device <NUM>. However, the system and method is not intended to be limited to this illustrative example.

<FIG> shows a process diagram for an example method executed at the controller <NUM> of the system shown in <FIG>, in which the controller <NUM> is integrated into the supervisor device <NUM>. Either the monitored device <NUM> or the surveillance zone device <NUM> is capable of determining a measure of the separation between the monitored device <NUM> and the surveillance zone device <NUM>, and then providing or transmitting this measure of separation to be received by the controller <NUM> at the supervisor device <NUM>. It should be noted that although the method of <FIG> is shown as considering a measure of separation to a threshold in order to determine if a device is inside or outside of its surveillance zone, a binary consideration of whether a wireless connection has been made (as discussed above with respect to the method of <FIG>) could instead be used to determine whether a device is inside or outside of its surveillance zone.

The system begins in an idle mode <NUM>. In an idle mode <NUM>, the controller <NUM> may periodically transmit and receive signals from the surveillance zone device <NUM> and the monitored device <NUM>, in order to obtain or determine information on the separation between each of the surveillance zone device <NUM>, the supervisor device <NUM> and the monitored device <NUM>.

In the event that the controller <NUM> at the supervisor device <NUM> obtains a determination that the separation (distance d(SZ)) between the supervisor device <NUM> and the surveillance zone device <NUM> is less than or equal to a first threshold T<NUM>, as well as receiving a determination that the separation (distance d(MZ)) between the monitored device <NUM> and the surveillance zone device <NUM> is less than or equal to a second threshold T<NUM>, the system moves <NUM> to a monitoring state <NUM>. In the illustrative application, these conditions indicate that the supervisor device <NUM> (associated with the parent or guardian) and the monitored device <NUM> (associated with the child) have moved into their surveillance zone around the surveillance zone device <NUM> (defined as an area around the surveillance device attached to a beach umbrella), and so the separation monitoring should begin.

It will be understood that this step <NUM> of moving into the monitoring state <NUM> (and the idle state <NUM>) is optional, as the system could be activated directly into the monitoring state <NUM> by a user via the controller <NUM>. For instance, a parent or guardian could activate the monitoring state <NUM> via an application running at the supervisor device <NUM>.

Once in a monitoring state <NUM>, the controller <NUM> will periodically transmit and receive signals from the surveillance zone device <NUM> and a monitored device <NUM>. The transmission and receipt may take place with greater frequency in the monitoring state <NUM> than in the idle state <NUM>. The system continues in the monitoring state <NUM> whilst the same conditions persist (in other words, whilst the extent of separation (distance d(SZ)) between the supervisor device <NUM> and the surveillance zone device <NUM> is less than or equal to a first threshold T<NUM>, the extent of separation (distance d(MZ)) between the monitored device <NUM> and the surveillance zone device <NUM> is less than or equal to a second threshold T<NUM>, then the monitoring state <NUM> continues). In the illustrative example of the system, the monitoring state <NUM> would continue whilst the supervisor device <NUM> associated with the parent and guardian and the monitored device <NUM> associated with the child are inside the perimeter of their surveillance zone defined around the beach umbrella to which the surveillance zone device <NUM> is attached.

However, if the controller <NUM> obtains a determination that one or both of the supervisor <NUM> and monitored <NUM> device(s) leave their surveillance area, then the system leaves the monitoring state <NUM>. For instance, under a particular set of conditions <NUM>, the controller <NUM> obtains a determination that the separation (distance d(SZ)) between a supervisor device <NUM> and the surveillance zone device <NUM> has exceeded a first threshold T<NUM>. The controller also obtains a determination that the separation (distance d(MZ)) between a monitored device <NUM> and the surveillance zone device <NUM> is less than or equal to a second threshold T<NUM>. In this way, according to the illustrative example, the system determines the parent or carer associated with the supervisor device <NUM> has left the child associated with the monitored device <NUM> alone in their surveillance zone. Consequently, the system moves to a pre-alert state <NUM>.

Alternatively, under another set of conditions <NUM>, the controller <NUM> obtains a determination that the separation (distance d(SZ)) between a supervisor device <NUM> and the surveillance zone device <NUM> is less than or equal to a first threshold T<NUM>. The controller <NUM> also obtains a determination that the separation (distance d(MZ)) between a monitored device <NUM> and the surveillance zone device <NUM> has exceeded a second threshold T<NUM>. In this way, according to the illustrative example, the system determines that the child associated with the monitored device <NUM> has left their surveillance zone, although the parent or guardian associated with supervisor device <NUM> remains within their surveillance zone. Consequently, the system moves to a pre-alert state <NUM>.

Under a still further set of conditions <NUM>, the controller <NUM> obtains a determination that the separation (distance d(SZ)) between a supervisor device <NUM> and the surveillance zone device <NUM> is greater than a first threshold T<NUM>. The controller <NUM> also obtains a determination that the separation (distance d(MZ)) between a monitored device <NUM> and the surveillance zone device <NUM> is greater than a second threshold T<NUM>. According to the illustrative example, this indicates both the parent or guardian associated with the supervisor device <NUM> and the child associated with the monitored device <NUM> have left their surveillance zone. Under this third condition, the system then proceeds to obtain a determination of the separation (distance d(SM)) between the supervisor device <NUM> and the monitored device <NUM>. If this separation (distance d(SM)) is greater than a third threshold T<NUM>, then the system moves from the monitoring state <NUM> to the pre-alert state <NUM>. According to the illustrative example, these conditions indicate that both the parent or guardian associated with the supervisor device <NUM> and the child associated with the monitored device <NUM> have left their surveillance zone, and that they do not appear to have done so together.

In contrast, if, under a yet still further set of conditions <NUM>, the controller <NUM> obtains a determination that the separation (distance d(SZ)) between a supervisor device <NUM> and the surveillance zone device <NUM> is more than a first threshold T<NUM>, and that that the separation (distance d(MZ)) between a monitored device <NUM> and the surveillance zone device <NUM> has exceeded a second threshold T<NUM>, whilst also that the separation (distance d(SM)) between the supervisor device <NUM> and the monitored device <NUM> is less than or equal to a third threshold T<NUM>, then the system moves from the monitoring state <NUM> back to the idle state <NUM>. According to the illustrative example, this set of conditions indicates that although both the parent or guardian associated with the supervisor device <NUM> and the child associated with the monitored device <NUM> have left their surveillance zone, they have done so together (and so it can be assumed the child is still being supervised).

When in the pre-alert state <NUM> the system allows a predefined time interval t to elapse. During this time, the controller may continue to obtain determination of the separation between each of the devices. If, after elapse of the predefined time interval t the controller determines the separation between each of the surveillance zone device <NUM>, the supervisor device <NUM> and the monitored device <NUM> still fall within one of the sets of conditions described above described for entry to the pre-alert state <NUM>, then the system will this time proceed to initiate an alert <NUM>. The alert <NUM> may be an alarm sounded at the supervisor device <NUM>, for example. Alternatively, the alert may be a telephone call or text notification to a nominated device (such as the supervisor device <NUM>).

In contrast, if, whilst the system is in the pre-alert stage <NUM>, during or at the elapse of the time interval t the controller <NUM> obtains a determination <NUM> that the separation (distance d(SZ)) between the supervisor device <NUM> and the surveillance zone device <NUM> is less than or equal to a first threshold T<NUM>, as well as receiving a determination that the separation (distance d(MZ)) between the monitored device <NUM> and the surveillance zone device <NUM> is less than or equal to a second threshold T<NUM>, the system reverts back to a monitoring state <NUM>. In the illustrative example, this would be the case if both the parent or guardian associated with the supervisor device <NUM> and the child associated with the monitored device <NUM> move back inside their surveillance zone, and so no alert is necessary.

A further possibility is that, whilst the system is in the pre-alert stage <NUM>, the controller <NUM> obtains a determination <NUM> that although the separation (distance d(SZ)) between a supervisor device <NUM> and the surveillance zone device <NUM> is more than a first threshold T<NUM>, and the separation (distance d(MZ)) between a monitored device <NUM> and the surveillance zone <NUM> device is more than a second threshold T<NUM>, also the separation (distance d(SM)) between the supervisor device <NUM> and monitored device <NUM> is less than or equal to a third threshold T<NUM>. In this case, the system moves from a pre-alert state <NUM> back to the idle state <NUM>. According to the illustrative example, this might indicate that both the parent or guardian associated with the supervisor device <NUM> and the child associated with the monitored device <NUM> have left their surveillance zone, but are still in close proximity to each other.

<FIG> illustrates various scenarios for the system and method of <FIG> and <FIG>, respectively. In <FIG>, the system is in a monitoring state <NUM>. In particular, the separation (distance d(SZ)) of the supervisor device <NUM> from the surveillance zone device <NUM> is less than or equal to a first threshold T<NUM>, and the separation (distance d(MZ)) of the monitored device <NUM> from the surveillance zone device <NUM> is less than or equal to a second threshold T<NUM>. In this case, second threshold T<NUM> represents a shorter distance than first threshold T<NUM>, and so the surveillance zone for the parent or guardian associated with the supervisor device <NUM> is a larger area than the surveillance zone for the child associated with the monitored device <NUM>. Nevertheless, as both the supervisor device <NUM> and monitored device <NUM> are inside their assigned (concentric) surveillance zones, then no alert is necessary and the system remains in the monitoring <NUM> state (and does not move to the pre-alert state <NUM>).

<FIG> illustrates the scenario in which a set of conditions for entering the pre-alert state, as described above, is met. In particular, the separation (distance d(SZ)) between the supervisor device <NUM> and the surveillance zone device <NUM> is greater than a first threshold T<NUM>, whilst the separation (distance d(MZ)) between the monitored device <NUM> and the surveillance zone device <NUM> is less than or equal to the second threshold T<NUM>. As such, the parent or guardian associated with the supervisor device <NUM> appears to have left their assigned surveillance zone, but leaving the child associated with the monitored device <NUM> within their surveillance zone. Therefore, the pre-alert state <NUM> is initiated. If the conditions remain unchanged, then an alert <NUM> will be initiated after elapse of a predetermined time interval t.

<FIG> illustrates the scenario in which another of the sets of conditions for entering the pre-alert state, as described above, is met. In particular, the separation (distance d(SZ)) between the supervisor device <NUM> and the surveillance zone device <NUM> is less than or equal to a first threshold T<NUM>, whilst the separation (distance d(MZ)) between the monitored device <NUM> and the surveillance zone device <NUM> is greater than the second threshold T<NUM>. As such, the child associated with the monitored device <NUM> appears to have left its assigned surveillance zone, but leaving the parent or guardian associated with the supervisor device <NUM> within their assigned surveillance zone. Therefore, the pre-alert state <NUM> is initiated. If the conditions remain unchanged after elapse of a predetermined time interval t, then an alert <NUM> will be initiated.

<FIG> illustrates the scenario in which another set of conditions for entering the pre-alert state, as described above, is met. In particular, the separation (distance d(SZ)) between the supervisor device <NUM> and the surveillance zone device <NUM> is greater than a first threshold T<NUM>, whilst the separation (distance d(MZ)) between the monitored device <NUM> and the surveillance zone device <NUM> is greater than the second threshold T<NUM>. Furthermore, the separation (distance d(SM)) between the supervisor device <NUM> and the monitored device <NUM> also exceeds a third threshold T<NUM>. As such, the parent or guardian associated with the supervisor device <NUM> and the child associated with the monitored device <NUM> appear to have left their assigned surveillance zones, but not together. Therefore, the pre-alert state <NUM> is initiated. If the conditions remain unchanged after elapse of a predetermined time interval t, then an alert <NUM> will be initiated.

<FIG> illustrates a further scenario in which a set of conditions set out above are met. In particular, the separation (distance d(SZ)) between the supervisor device <NUM> and the surveillance zone device <NUM> is greater than a first threshold T<NUM>, whilst the separation (distance d(MZ)) between the monitored device <NUM> and the surveillance zone device <NUM> is also greater than the second threshold T<NUM>. However, the separation (distance d(SM)) between the supervisor device <NUM> and the monitored device <NUM> is less than or equal to a third threshold T<NUM>. As such, the parent or guardian associated with the supervisor device <NUM> and the child associated with the monitored device <NUM> appear to have left their assigned surveillance zones together, and the pre-alert state <NUM> does not need be initiated. In fact, the system can return to the idle state <NUM>, for instance to conserve power.

<FIG> illustrates certain scenarios in which more than one supervisor device <NUM>, or more than one monitored device <NUM>, is used. As an illustrative example, a first and second supervisor device <NUM> could be used, each associated with a different parent or guardian. Alternatively a plurality of monitored devices <NUM> could be used, each associated with one of a group of children.

<FIG> illustrates a scenario in which a first 20a and a second 20b supervisor device is present, and a single monitored device <NUM>. Here, the separation (distance d(MZ)) between the monitored device <NUM> and the surveillance zone device <NUM> is less than or equal to the second threshold T<NUM>. The separation (distance d(SaZ)) of the first supervisor device 20a and the surveillance zone device <NUM> is less than or equal to the first threshold T<NUM>. However, the separation (distance d(SbZ)) of the second supervision device 20b from the surveillance zone device <NUM> is greater than the first threshold T<NUM>. In this case, the system remains in a monitoring state <NUM> (rather than moving to a pre-alert state <NUM>), because at least one of the supervisor devices 20a, 20b meets the requirements for being within the surveillance zone together with the monitored device <NUM>.

<FIG> shows the same devices in an alternative configuration. Here the separation (distance d(MZ)) between the monitored device <NUM> and the surveillance zone device <NUM> is less than or equal to the second threshold T<NUM>. However, the separation (distances d(SaZ), d(SbZ)) of both the first 20a and the second 20b supervisor device is greater than the first threshold T<NUM>. Under these conditions, the system is moved to a pre-alert mode <NUM>, and would initiate an alert <NUM> if the same conditions are met after elapse of a predefined time period t. In particular, these conditions indicate that the monitored entity <NUM> is within the surveillance zone, but all of the supervisor devices 20a, 20b have left the surveillance zone, apparently leaving the entity associated with the monitored device <NUM> unattended.

<FIG> shows a further scenario in which three monitored devices 30a, 30b, 30c are used, and a single supervisor device <NUM>. Here, the separation (distance d(SZ)) of the supervisor device <NUM> from the surveillance zone device <NUM> is less than or equal to a first threshold T<NUM> (and so the supervisor device <NUM> is considered to be within its assigned surveillance zone). Two of the monitored devices 30a, 30b are separated from the surveillance zone device by a distance d(MaZ), d(MbZ) less than or equal to the second threshold T<NUM>. However, the separation (distance d(McZ)) between the third monitored device 30c and the surveillance zone device <NUM> exceeds the second threshold T<NUM>. As at least one of the monitored devices 30a, 30b, 30c meets the conditions for entering a pre-alert state <NUM>, the system moves from the monitoring state <NUM> to the pre-alert state <NUM>. An alert <NUM> will be issued if the same conditions persist after elapse of a predefined time period t.

<FIG> shows a further example of the described system. In this embodiment, only a surveillance zone device <NUM> and monitored device <NUM> are used. A controller may be integrated into the surveillance zone device <NUM> in order to be able to perform the method. This example of the system may monitor separation in order to issue an alert if a monitored device <NUM> enters a surveillance zone. For example, this system could be used for the purposes of maintaining social distancing, wherein the surveillance zone device associated with a user, and the monitored device is associated with another person from whom the user must maintain at least a particular distance.

In the example of <FIG>, the system is in the monitoring state <NUM>. A surveillance zone is established having a perimeter at a distance to the surveillance zone device <NUM> equal to a first threshold T<NUM>. A monitored device <NUM> is separated from the surveillance zone device <NUM> by a separation (distance d(MZ)) greater than the first threshold T<NUM>, and so no action is taken. The system remains in the monitoring state <NUM>.

If the system determines that a monitored device <NUM> is separated from the surveillance zone device <NUM> by a distance d(MZ) less than or equal to the first threshold T<NUM> (such as shown in <FIG>), then the system may move to a pre-alert state <NUM>. If, after elapse of a predefined time period t, the separation (distance d(MZ)) of the monitored device <NUM> from the surveillance zone device <NUM> is still less than or equal to the first threshold T<NUM>, then an alert <NUM> can be initiated. Such an alert <NUM> may be an alarm sounded at the surveillance zone device <NUM>, for instance.

Typically, this example of the described system could be obtained via a mobile device application. For instance, both the monitored device <NUM> and the surveillance zone device <NUM> may be a smartphone executing a dedicated application. Any given mobile device may act as a surveillance zone device <NUM> or a monitored device <NUM>, or a stand-alone beacon could be used as the monitored device <NUM>. The mobile device may provide the controller or control unit, as well as the wireless technology functions and acoustic warning means such as an alarm.

For this example of the described system difficulties may be caused by certain wireless technologies (such as Wi-fi™, BluetoothRTM and ultra-wide-band) generating false alarms when two devices are close to each other but separated by a screen or wall. These issues can be overcome by making use of custom ultrasound sensing technology to determine the extent of separation between devices. Ultrasound sensing is functional to measure separation with lower precision than some alternative means, but is stopped or blocked by screens.

A number of combinations of the various described embodiments could be envisaged by the skilled person.

Although the above systems are described with the controller integrated into either the surveillance zone device <NUM>, or the supervisor unit <NUM>, it will be understood that the controller could be integrated into any of the devices, including the monitored device <NUM>. Any of the devices could be provided as simple stand-alone wireless beacons, provided functionality is available across the devices to determine the separation between the required devices (or whether a wireless connection is made), and to transmit the determined separations to the controller.

Although the above systems are described in view of illustrative embodiments in which the supervisor device is associated with a parent or guardian, and the monitor devices is associated with a child, it will be understood that the monitored device may be associated with a valuable item or property, under the supervision of a caretaker associated with the supervisor device. A preferred application of the described systems is within a vehicle (wherein the surveillance zone is housed within the vehicle) in order to provide a safety system for alert in the case of forgotten baby syndrome. However, the system could be used in any application where supervision of a monitored entity within a surveillance zone is required.

Claim 1:
A method for indicating excessive separation between a first wireless device and a second wireless device, the method comprising:
monitoring a separation of each of the first wireless device and the second wireless device to a third wireless device;
determining whether a set of conditions is met, the set of conditions being that the first wireless device is inside a first zone defined with respect to a third wireless device, and that the second wireless device is outside a second zone defined with respect to the third wireless device; and
if the set of conditions is met, then:
initiating an alert.