BE1022656B1 - VIRTUAL CLOSURE FOR DOGS - Google Patents

Abstract

The present invention relates to a virtual fence system for the confinement of an animal (1) in a confinement zone constituted by an authorized zone (7) separated from a prohibited zone (8) by a border (2)

Description

[0001] The present invention relates to an invisible fence system for confining animals, such as for example dogs. The principle is to warn the dog, for example by sound or vibratory means, when approaching a predefined boundary so that it remains confined in an authorized access zone, hereinafter authorized zone, delimited by this border. If, despite the warning, the dog crosses the said frontier to be in the zone of forbidden access, hereinafter prohibited zone, it receives then an electric stimulation which goes in increasing more it moves away from the authorized zone, and thus forces him to return to this one.

STATE OF THE ART [0002] A first known solution according to the prior art often recommends burying a conductive wire which delimits or materializes the boundary. This wire is traversed by an alternating current whose typical frequency is a few kHz. The dog is equipped with a collar that can detect the alternating magnetic field generated by the wire and stimulate the dog if it approaches the wire. This system however has many drawbacks: - it is necessary to bury a wire which determines a closed zone (enclosure). This is not easy when, for example, you have to cross paved roads; - it is not always possible to define an entry-exit portal that allows the dog to enter a house adjacent to the area or in a shelter (in case of rain for example); the use of an audible or vibratory warning is known, but the precision of the distance at which it occurs remains poor because the measurement of the intensity of the magnetic field depends on other elements than the distance; - some robots like automatic mowers also use this technology. There is often interference that can be problematic and prevent the installation of both systems on the same ground or on adjacent land; - if two fences are to be laid on adjacent land, problems appear at the junction of the land; - If the dog springs quickly and passes beyond the wire, the stimulation stops when it should increase once the limit is reached. He therefore receives only a brief electrical stimulation which is insufficient to stop him. Even worse, if the dog tries to return to the authorized zone, he will receive a new stimulation when crossing the border, which does not encourage him to return to the authorized zone; - There is no possibility to detect the movement of the dog, as well as the direction taken by the dog. An action should be earlier in the case where the dog runs perpendicular to the fence in relation to the case where it runs along it. In addition, it can happen that a dog remains stuck in bushes along the fence, using the buried wire system. The dog can then receive stimulation for long minutes while it is still, that is to say during the time necessary for the system to get safe: this is contrary to animal welfare; - It is possible to easily steal a collar or cable and reuse it.

To overcome the problems of the technology described above, the use of differential GPS (DGPS) has been proposed in US 6,903,682 B1 for a dog location application. The idea is to locate the dog carrying a GPS and to apply warnings and stimulations according to his position. This technology solves the problems mentioned above but introduces others, in particular: - the consumption of a GPS is much higher than that of a field detector, so that the autonomy of the collar worn by the dog is very weak, that is to say limited to a few hours, with the use of a battery of reasonable size; - the accuracy of the DGPS is insufficient and does not allow the dog to reproducibly identify the authorized limit not to exceed. This precision deteriorates all the more as the animal approaches buildings. The dog's learning is therefore compromised; - The start-up time is very long, of the order of a few minutes (acquisition of GPS data and corrections on a statistical basis). It is therefore necessary to wait long minutes before being able to release the dog in the protected zone.

The state of the art is described below in a series of documents, without this state of the art is considered exhaustive.

[0005] GB200816469 describes an industrial process protection by selective access authorization according to the position and the identity of the carrier of a portable communicator (electronic tag). The position of the user can be determined by RTLS.

[0006] CA2709171 describes worker protection on railway tracks based on the detection of the worker carrying a "tag", a central system determining the worker's position relative to the approaching train and warning him as soon as he has left him that little time to get away. The terminals that litter the course of the train are for example connected to each other using son.

[0007] US200810099 discloses a system for protecting people by determining their position vis-à-vis industrial processes. These processes can in no case start if a zone has not been evacuated for example. The problem is very similar to that of GB200816469.

[0008] CN102768352 and CN202770989U describe a mining protection system (underground) based on joint localization in UWB and ultrasound, necessitated by a large number of echoes.

[0009] EP2226646 describes a "relative" or "mobile" location system. The system includes wireless transceiver modules connected to a wireless network. Among these there is a central "anchor" of known position in the space considered and acting as a base station, the other modules having a position to be determined with respect to this base station. Nevertheless, no means are advanced to define a boundary delimiting a danger zone.

[0010] DE202008005467 describes a system for locating people in a tunnel from anchors in the form of wireless transmitters / receivers whose position is known.

CN101571406 discloses a pet location system.

[0012] IT2004BA0059 describes a system for locating people or animals which transmits the position step by step through a network of fixed transmitters / receivers and which are aware of their absolute position.

[0013] US2003122666 discloses a triangulation position measuring system by acting on the phase of the received signals. The invention describes a method of positioning requiring anchors whose positions and orientations are known.

WO200398528 discloses a method of measuring distance between two objects provided with RF tags.

US20030052776 discloses a method of measuring distance between two objects based on UWB.

BR9000368U describes a positioning system bracelet with remote reading and automatic.

EP2282106 describes a system for locating workers in an area by laser scanning.

[0018] KR101258905 describes a worker protection system having only two RTLS tags (position of a crane and a worker's position) and an access point connected to a server.

KR20110017707 describes a location system in a tunnel from fixed terminals (similar to CA2709171).

CA2768054 discloses a complex location system using the power method received in a building. The system requires a calibration phase but checks itself whether there are enough anchors. The system needs to be told the building topology, access points, etc.

US2010017126 describes a location system, visibly GPS or SPS satellite, in which a visibly circular area is defined with respect to a first localized object. Then a series of alerts are given if other objects approach this first object.

JP2009020847 describes a system for preventing accidents of elderly or disabled using anchors placed inside a home. Each tag receives a signal strength from a tag, which makes it possible to determine if a tag is near an anchor and give an alert if necessary. Communication is via the electrical network (such as a lamp supply line for example).

[0023] WO2006085280 discloses a system for tracking animals over large areas based on GPS and using relays.

[0024] US2004087314 describes a system for locating a tag with respect to a single anchor using distance and angle measurements. Many general ideas are cited in this document such as the use of a touch screen but few details are given on how to build the system or manage obstacles. The desired precision is not mentioned either.

[0025] WO 2006/067826 A1 describes a relatively inaccurate animal location system, while accuracy is essential to allow the animal to learn the exact limit it can not cross.

The following documents are also of interest in the context of the present invention: - the document Analytical Localization Method for Wireless Sensor Embedded Nodes In Industrial Processes, M. Antoniou, Green PN, 2013 IEEE, describes a localization system of grain in a silo. Some concepts are close to the proposed invention (see page 2, second column); EP 1 968 359 (Circuit and method for checking the impedance of electrodes and controlling the intensity of an electrical stimulus) and EP 2 365 738 (High voltage circuit for electrical stimulation) both describe means for controlled electrical stimulation to avoid overstimulation of the dog.

OBJECTS OF THE INVENTION [0027] The present invention aims at providing a solution that makes it possible to overcome the disadvantages of the state of the art.

In particular the invention aims to provide the problem solving means of giving a warning to a dog approaching a border and send him a stimulation (electrical, ultrasound, etc.) when cross this one.

The invention also aims to provide the ability to locate the dog accurately, while consuming little energy using a system whose cost remains close to that of existing solutions.

In a very general manner, the invention also aims to locate a "tag", that is to say a mobile object such as an automatic clipper, a living being, etc.. in a defined area by replacing or not replacing a buried wire border creation system.

Main Characteristic Elements of the Invention [0031] A first aspect of the present invention relates to a virtual fence system for the confinement of an animal in a confinement zone constituted by an authorized zone separated from a prohibited zone by a boundary, comprising: - a plurality of fixed reference terminals called anchors distributed in said confinement zone and a central unit, said anchors communicating bidirectionally with each other and with the central unit, and able to measure the distance between them; each other with a precision at least equal to a predetermined value, the central unit being able to establish a two-dimensional landmark or XY, that is to say to assign a position to at least two anchors and then locate the other anchors in this XY frame by a trilateration or vote probability estimation method; at least one mobile electronic device comprising a transceiver, called tag or collar, carried by the animal and capable of communicating bidirectionally with the central unit, as well as measuring by trilateration the distance separating it from each of the anchors, said tag being provided with means of warning and stimulation of the animal operable by the central unit, to warn the animal when it approaches the border in the authorized area and to stimulate the animal when the latter cross the border or move away from it into the prohibited zone; means for tracing the boundary between the authorized zone and the forbidden zone from the position of the anchors once located in the aforementioned XY marker.

According to preferred embodiments, the system according to the invention is further limited by at least one of the following features, or an appropriate combination thereof: the central unit is provided with a controller and input / output means comprising pushbuttons and a screen, preferably a touch screen; the bidirectional communication means equipping the tag, the anchors and the central unit are equipped with conventional ISM or UWB broadband radio transmitters and / or ultrasonic transducers with a time of flight measurement method; the warning means are acoustic and / or vibratory means and the stimulation means are means for applying a high voltage pulse; the predetermined value of precision on the determination of the distance, separating the anchors between them, is 50 cm, preferably 10 cm; the position calculation from the anchor-tag distances is deported to the central unit, said central unit performing a position interrogation at a fixed periodicity, which makes it possible to activate the anchors and the tag only during a short time interval with respect to the interrogation period, this time interval being preferably of the order of 5% of said periodicity; - The communication between the central unit, on the one hand, and the anchors and the tag on the other hand, is performed by means of a dedicated ISM radio channel; - The tag and the anchors are powered by rechargeable battery, the anchors are also equipped with a small photovoltaic panel; the tag is equipped with a motion detector in the form of an accelerometer making it possible to indicate to the central unit that the tag has remained immobile since the last positioning and thus to avoid the implementation of a query of position by the central unit; - The tag is equipped with a GPS and a GSM module allowing the owner of the animal to locate the animal by SMS exchange, especially when the animal has fled after leaving the authorized area; the functionalities of the central unit and / or the means for tracing the border are incorporated in the collar.

A second aspect of the present invention relates to a method of implementing the animal containment system by means of a virtual fence in a confinement zone, according to any one of the preceding claims, characterized by at least the following steps: - the plurality of anchors are installed arbitrarily in said confinement zone; the central unit interrogates the plurality of anchor terminals and determines the distances separating them from each other as well as the distance separating them from the central unit; the central unit establishes a two-dimensional reference reference mark or XY which will be used for locating the animal; a closed boundary of the confinement zone is determined, said closed boundary being defined as being a polygon, that is to say a set of points or vertices connected by straight line segments or sides; - In operation, it provides a collar or tag an animal brought to be in the confinement zone; the central unit periodically interrogates the tag, determines its position in the XY coordinate system and assigns each of these tag positions a location either in the authorized zone or in the forbidden zone; if the tag is in the authorized zone and approaches the border, the central unit activates the warning means associated with said tag and if the tag crosses the border or is in the forbidden zone and moves away from the border. border, the central unit activates the stimulation means associated with said tag.

Still according to the invention, the boundary is determined: either by using a location of the anchors in the XY mark displayed on a touch screen associated with the central unit and by drawing said border on the touch screen in the form of polygon supra; or by using a device called a tracer which communicates with the central unit and the reference terminals, the central unit periodically interrogating the tracer when it is moved in the zone and asking it for the respective distances separating it from the reference terminals, which allows the CPU to determine the successive positions of the plotter in the XY coordinate system and to create the border by joining these positions by line segments to create the aforementioned polygon.

Still according to the invention, the XY mark is established in the following manner by the central unit: a first anchor is arbitrarily assigned to the coordinate (0, 0); a second anchor at a distance d is assigned to the coordinate (d, 0); a third anchor is located from the two aforementioned anchors using the intersection of two circles from the respective distances of the third anchor with respect to the two aforementioned anchors, one of the two possible intersections being chosen arbitrarily as the position of the third anchor; - the following anchors are located from the first three anchors using a trilateration algorithm.

Advantageously, the determination of the position of a tag T is carried out using two anchors of known position A1 and A2, respectively separated from T by distances d1 and d2, the tag T being at intersection of circles respectively centered at A1 and A2 and respective radii d1 and d2, two positions being possible, denoted Ta and Tb, characterized in that the most probable position of Ta and Tb is determined by voting according to minus the following five successive steps: - 0 points are initially assigned to the two positions Ta and Tb; at least one other anchor A3, different from A1 and A2, the measured distance d3 of which is separated from the tag T, is selected, the respective distances d3a and d3b are calculated between A3 and the two potential positions Ta and Tb of tag T, we assign 3 additional points to the position Ta or Tb whose distance from the anchor A1 or A2 is the closest to d3 and we do not assign any point to the other position, that is to say say o if | d3 - d3a | <| d3 - d3b | => 3 additional points awarded Ta; o else => 3 additional points attributed to Tb; the previous position, preferably the position of the tag T determined during a previous interrogation by the central unit, is used, the Euclidean distance between this previous position and each of the positions Ta and Tb being known, 2 additional points being allocated. at the position that has the smallest distance from the previous position; - We vote against at least one other anchor A3 whose distance is unknown, that is to say such that the distance measurement between the T tag and the aforementioned A3 anchor failed, because of the large distance separating the T-tag from the anchor A3 or because of an imposing obstacle, assigning 1 point to the furthest position from the anchor A3, ie: o if d3a> d3b => 1 additional point attributed to Ta; o else => 1 additional point attributed to Tb; - Of the 2 positions Ta and Tb, the one that has accumulated the most points in the previous steps is selected as the most probable position of the tag T.

According to a preferred embodiment of the invention, in the case where a dwelling M1, provided with a door P1, is accessible to the animal, access to the door P1 is made via a zone Z2, said portal area, separating the dwelling M1 Z1 area where the animal is allowed to circulate, characterized in that it further comprises the following steps: - after location, the position of the animal is that is to say the inclusion or not of it in the zone Z1 or Z2, is determined; if the animal is in zone Z2, the warning and stimulation system is deactivated whatever the future position of the animal; if the animal is not in zone Z2 but in zone Z1, the warning and stimulation system is reactivated if it had previously been deactivated.

Still according to the invention, a coercive level scale ranging from 0 to 100% is applied so as to push the animal back into the authorized area when it leaves it to go to the forbidden zone, a 50% coercive level corresponding to the value below which a warning is communicated to the animal and above which a stimulation is communicated to him, characterized by the following steps: in authorized zone, when the animal is approach, respectively moves away from the border, the level of warning increases, respectively decreases linearly, the coercive level being less than or equal to 50%; - in forbidden zone, the level of stimulation increases according to a linear law up to a maximum level of 100% as the animal moves away from the border; - in the forbidden zone, when the animal approaches again the border after having moved away from it, the level immediately goes to 50%, thus with suppression of stimulation.

BRIEF DESCRIPTION OF THE FIGURES [0039] FIG. 1 schematically represents a general and synthetic view of the virtual fence system for the confinement of an animal according to the present invention.

FIG. 2 represents an exemplary embodiment of the system according to the present invention, comprising the following three basic elements: collar, reference terminal (s) and central unit.

Figure 3 schematically shows the creation of an XY landmark.

FIG. 4 represents the principle of determining the position of a tag according to the invention, using two anchors of known position.

FIG. 5 shows how, knowing the two potential positions Ta and Tb and knowing the position of the anchor A3, the distances d3a and d3b can be perfectly determined.

Figure 6 shows an example of use of an exit gate, according to the present invention.

Figure 7 shows how the management of warnings and stimulations is performed by adaptation of the coercive level.

DETAILED DESCRIPTION OF THE INVENTION The generic problem to be solved therefore comprises at least the following steps: locating a dog, generally, in real time and permanently, sending him a warning (for example vibratory or audible) when he approaches the border, - send him a stimulation (for example electric or ultrasound) when he crosses the border, - get statistics of position of the dog (where does he spend the most time? where does he go?).

The invention must also be able to solve ancillary problems such as tracing the border, managing an exit portal, taking into account prohibited internal areas (such as a parterre for example), the implementation of place an anti-theft system and control this system.

The solution proposed in the context of the present invention is to place reference terminals, typically 5, around and / or in the area in which the dog is allowed to circulate.

The dog is provided with an electronic device for example mounted in a collar, hereinafter called in summary "collar", which is capable of measuring the distance separating it from each of the terminals. The distance measurement can be performed using ultrasound, optical means or UWB signals.

The targeted system, however, preferably use UWB signals, because of their excellent range, compact implementation and low consumption. It will be advantageous to use a central system management unit that is accessible to the user.

The central unit preferably communicates by means of ISM radios to the reference terminals and to the collars. It is possible to use the UWB signals as radio means but it is recommended according to the invention to use a different radio channel (433 or 868 MHz for example) because of its lower consumption and its different range.

On periodic order of the central unit (transmitted by radio), the collar performs a measurement of distance to the neighboring terminals. It collects these distances and transmits them to the central unit. The latter first determines the position of the dog relative to the terminals in an XY reference linked to the reference terminals and whose position is known in this reference.

Then the central unit determines whether or not the dog is in the authorized area and, if so, how far from the border it is. Based on this information, the central unit determines whether the dog should be warned or whether electrical stimulation should be applied. The central unit then transmits the order by the radio means to the collar.

If the dog (with its collar) comes out of the authorized zone, the central unit informs the collar which can then activate a built-in GPS and transmit its GPS coordinates by SMS to a mobile phone (GSM) and to the unit central, by means of the radio channel, to allow the master to find his dog.

The present invention therefore relates to a system, the general principle of which is represented in FIG. 1 and which is composed from three main elements: an individual collar (per dog), reference terminals and a central unit as shown in Figure 2.

A variant of the invention consists in integrating the central unit into the collar while sacrificing some of the advantages as described below.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION [0057] Particular embodiments of the invention relate to the elements described below. 1. Installation The system according to the present invention can warn the dog or any other animal located near a prohibited area. This warning is via a transceiver, or tag or tag, worn by the dog directly in the form of a collar for example. For example, the transceiver or the tag emits acoustic and vibratory signals combined or not.

The operation of the system requires that each transceiver be able to locate with respect to the prohibited area or the border thereof. To do this, several reference terminals are placed in the field. After the laying of the terminals, a configuration step preferably consists of moving a special transceiver called "tracer" along the boundary between the authorized zone and the forbidden zone. This step allows the system to record a set of positions that ultimately define the warning limit in the form of a "virtual fence." The recording is done in a remote central unit and mains powered.

The location of the above-mentioned transceiver with respect to the terminals is performed by a trilateration or triangulation system.

A particularity of the invention is that the definition of the authorized area is during the tracing while the terminals were initially arbitrarily laid and that the position of the reference terminals is unknown during the installation of the device and will remain so throughout the operation of the device. The resolution of this apparent contradiction is an element of the invention.

A second feature is the protection of the system against measurement errors by the redundancy of measurements and the redundancy of communication channels between the terminals, the (or) receiver (s) and the central unit.

According to the invention, the position of the dog must be obtained quickly, accurately (+/- 10 cm for example) indoors and outdoors. This last point excludes any solution based on a system of geolocation (GPS).

More specifically, we want to map, according to the invention, a given space in two areas: - an authorized area; - a forbidden zone.

The problem to be solved is then reduced along two axes: - provide a solution to define and locate these two areas and - provide a solution to determine in which area an animal is with a desired location accuracy of +/- 10 cm for example.

FIG. 1 schematically shows the various constituent elements of the system of the invention: a dog or, in general, an animal 1, carrying a collar 6, reference terminals 3, a central control unit 4, a tracer 5 and the boundary 2 between the authorized zone 7 and the prohibited zone 8.

An exemplary embodiment of the system according to the present invention, comprising the following three basic elements: collar 6, reference terminal (s) 3 and central unit 4, is shown in FIG. 2.

The proposed solution is based on a set of reference terminals 3 which are distributed more or less uniformly in (or around) the area in which we want to achieve the positioning of the dog.

These reference terminals 3 communicate with each other and also communicate to a central unit 4. It is this central unit that orchestrates the entire system. In a preferred implementation, this central unit 4 is placed in a bag and is provided with a screen, touch or not, and pushbuttons (not shown). In another preferred implementation, the central unit 4 could be provided with fastening means on an interior wall of the house, for example near the exit door of the dog, which would allow the user to check the correct operating state of the system before releasing the animal.

The reference terminals 3 are also capable of measuring the distance separating them by means known to those skilled in the art. One solution, for example, is to use UWB radio transmitters or ultrasonic transducers with a TOF (time of flight) method.

It will be noted that the UWB technology, like other technologies, can evaluate a degree of reliability over the distance returned as well as the presence of potential obstacles. This information is advantageously used to reject any calculation distances considered unreliable.

Creating an "XY" Mark [0072] Once the reference terminals 3 have been installed, the user asks the system to check the placement of the terminals. To do this, the central unit 4 interrogates the set of reference terminals 3 and asks them the distance that separates each of them from each other.

[0073] Any location requires a reference mark. According to the prior art, it is still required that this marker be defined by assigning known positions to the reference terminals. The proposed invention, however, does not require this heavy constraint for a system that needs to be installed quickly.

From the distance information collected about the reference terminals, the central unit determines an XY fixture that will be used for further localization. This determination works for example in several steps (see Figure 3): 1) A terminal 10 is arbitrarily assigned to the coordinate (0, 0). 2) A second terminal 20 which is at a distance d is assigned to the coordinate (d, 0). 3) A third terminal 30 is located from the other two using the intersection of two circles from the distance information (= radius of the circles). This creates ambiguity because there are two possible intersections. One of the two positions is then chosen arbitrarily. 4) At this stage, since three reference terminals are located, all the other terminals (eg terminal 40 in the figure) can be located by trilateration algorithms known to those skilled in the art. 5) A refinement step is possible once all the coordinates of the determined terminals. This step aims to make the localization algorithm insensitive to the initial choice of terminals in steps 1), 2) and 3).

It will be noted that the choice of the terminals in steps 1), 2) and 3) can be based on the reliability of the distance measurements. The terminals corresponding to the most reliable distance measurements will thus preferably be chosen.

However, it is important to note that the proposed method implicitly requires that each terminal can measure the distance separating it from at least three other terminals.

With the location algorithm below, as an alternative of the present invention, which requires only two terminals, the method of creating the XY mark just described above is automatically improved by the present invention. Determination of a boundary of the authorized / prohibited zone It is envisaged, according to the invention, to determine the boundary of the authorized / prohibited zone in at least two different ways from the position of the localized reference terminals. in an XY mark.

Touch Screen Location [0079] The reference terminals are located on a touch screen in an XY mark. It is then possible to draw on the touch screen a limit determining the authorized area. The boundary is then defined as a set of closely spaced points joined by straight line segments.

Localization by a tracer [0080] As already mentioned above, an apparatus called tracer 5 capable of communicating with the central unit 4 and the reference terminals 3 is moved along the border 2 by a person, for example by walking . The central unit 4 periodically interrogates (typically 10x per second) the tracer 5 and asks it for the distances separating it from the reference terminals 3. On the basis of this information, the central unit 4 determines the successive positions of the tracer 5 and creates thus a border 2 joining these positions approximated by segments of the line. As a non-limiting illustration, the tracer could be embodied in the form of a wheel provided with a handle. The wheel could be advantageously used to send the aforementioned periodic signal which would correspond to a given displacement thereof.

In another embodiment, the tracer 5 could be incorporated in the collar 6, the latter being configured via the central unit 4 as a tracer. The user would then construct the border 2 by moving along it, while wearing the collar 6. 2. Location [0082] According to one embodiment of the invention, the collar 6 is provided with a UWB transceiver capable of measuring the distance to the reference terminals, also equipped with a UWB transceiver. In the remainder of the description, the UWB transceiver to be located is called a "tag", the UWB transceivers present in the reference terminals and whose position is known in the XY frame are called "Anchors".

The generic problem thus comes down to locating a tag from the distances separating it from the anchors whose positions are known. By location, we mean to determine the coordinates (x, y) of the tag in the plane in which the coordinates (xa, ya) of the anchors are known.

Distance measurements by UWB are part of the prior art and are known to those skilled in the art.

In summary, the information provided to the location algorithm is: - the set of distances that separate the tag from each of the anchors, - an absence of distance information if it is impossible to measure the distance separating the tag from the anchor because of obstacles hindering the passage of radio signals or because the distance of the tag from the anchor is such that the measurement is impossible ("out of scope ").

[0086] The original principle of the algorithm is to determine a position using only 2 distances.

The advantage of this approach is to require a minimum of anchors in the system and therefore to reduce the cost.

[0088] FIG. 4 shows the principle of the algorithm according to one embodiment of the invention for determining the position of the tag "T" using two anchors of known position "A1" and "A2" ".

Knowing the distances separating the tag T from the anchors A1 and A2 and which are respectively d1 and d2, we know that the tag is on circles centered at A1 and A2 and respective radii d1 and d2. The algorithm performs including the intersection of two circles, which gives two possible positions for the tag noted Ta and Tb in Figure 4.

The problem to be solved is of course, that using two distances, there remains an indeterminacy as to the position of the tag.

An originality of the invention lies in the way to solve this problem in a systematic way. We proceed by vote to choose the correct position among the two positions, according to the following five steps: 1. The algorithm begins by allocating 0 points to the two positions Ta and Tb. 2. Vote in relation to other anchors whose distances are known: if we consider each of the other anchors (different from A1 and A2) that we call A3 and whose measured distance d3 is known from the tag, the algorithm can calculate the distances between A3 and the 2 potential positions Ta and Tb of the tag that are called d3a and d3b respectively (see Figure 5). The idea is to assign 3 additional points to the position whose distance from the anchor is the closest to d3 and to not assign any points to the other position. Formally:

Yes

additional points attributed to Ta (the vertical bar means "absolute value").

Otherwise => 3 additional points attributed to Tb. 3. Vote on the previous position: knowing the previous position of the previously determined tag (200 ms earlier for example), the algorithm calculates the Euclidean distance between this previous position and each of the positions Ta and Tb. The algorithm assigns 2 points to the position that has the smallest distance from the previous position. 4. Voting against other anchors for which distances are unknown: it is possible that a distance measurement between a tag and an anchor fails because of the large distance separating the tag from the anchor or because of a distance. Imposing obstacle. It is then possible to use this information to vote. Thus, if we consider each of the other anchors (different from A1 and A2) that we call A3 and whose distance to the tag is unknown, the algorithm can anyway calculate the distances between A3 and 2 potential positions Ta and Tb of the tag which one names d3a and d3b respectively. One point is awarded to the farthest position of the anchor A3. Formally:

If d3a> d3b => 1 additional point attributed to Ta.

Otherwise => 1 additional point attributed to Tb.

Here the idea is that among the 2 possible positions Ta and Tb, since no signal is received, the most probable position is the one furthest away from the A3 anchor, which justifies the attribution of the vote. 5. Of the 2 positions Ta and Tb, the one with the most points in the previous steps is selected as the position of the tag.

The number of points was chosen according to the degree of reliability of the vote. For example, if the distance from a third anchor could be measured, the positioning reliability is much higher than that based on the absence of a signal. Nevertheless, it is possible that in certain cases, only 2 anchors (A1 and A2) are visible and in this case, the vote N ° 4 is then able to separate the 2 positions.

In summary, the steps 1) to 5) allow from 2 anchors A1 and A2 whose distances are known with respect to the tag, to determine two potential positions. Then, using all the other anchors (which we call A3), it is possible to choose one of the two potential positions. The result of steps 1) to 5) is therefore an estimate of the position of the tag.

It is clear that steps 1) to 5) can be applied several times by selecting other anchors A1 and A2 at the start. Thus, several applications of the algorithm make it possible to obtain several estimates of the position of the tag that can be combined, using a possibly weighted average, to increase the accuracy. 3. Energy Management According to one embodiment of the invention, it is possible to shift the position calculation from the terminal-clamp (anchor-tag) distances to a central unit that can easily be powered from mains. . Thus, the energy consumption of location algorithms will have no impact on the autonomy of the system. It is obvious, however, that for ecological reasons, all the necessary measures must be taken to limit the consumption of the central unit.

According to one embodiment of the invention, the central unit speeds periodic position requests to a multiple of a fixed period, such as for example every 200 ms. Thus, after processing a positioning request, the terminals and collars can go to sleep for a little less than 200 ms (195 ms for example) because they are sure that the following request will occur only 200 ms later . They will wake up for about 10 ms to be sure to receive the new order.

The economy is therefore double: - the use of a separate radio channel will be preferred because it is less energy intensive than the use of a UWB channel because the current state of the art is that a UWB receiver typically consumes ten times more energy than a more conventional receiver working in a narrower band; - the fact of clocking the positioning requests at a fixed rate every 200 ms ensures that the terminals and collars will only wake up 195 ms after the previous order and this, for about 10 ms. Thus, if the consumption of the radio channel is 10 mA in reception, this consumption will be reduced to the effective time of ignition of the receiver: 10 mA x 10 ms / 200 ms = 0.5 mA.

The positioning commands sent by the central unit will include the following information: - the number of the collar that must perform the distance measurements, - the terminal numbers that must be taken into account. UWB transceivers will only be woken up when strictly necessary thanks to the information provided by the above orders. They will be woken at most every 200 ms and only when a distance measurement request concerns them.

In case of non-reception of a positioning command following a sporadic disturbance of the radio channel, the collar or the terminals will wake up permanently to receive the next order and will resynchronize and the rate of 200 ms.

Once the distances measured between the collar (tag) and the terminals (anchors), they will be sent back to the central unit by the radio channel. Note that if a distance could not be measured, the measurement incapacity information will also be sent back to the central unit.

According to one embodiment of the invention, a motion detector will be placed on the collar of the dog, which consists of a small accelerometer whose consumption is very low. Thus, the collar will be able to determine whether it is at rest or not. If it is at rest, during a positioning request sent by the central unit, it will be able to transmit a short answer meaning simply that it has not moved since the last positioning and will thus avoid making a measurement of distance by UWB means. This will achieve a substantial energy saving when the dog is at rest.

According to one embodiment of the invention, the collar and the terminals will be powered by battery. Since the collar must be removed from the dog periodically to avoid necrosis problems, the collar can be easily reloaded at this time.

For practical use, the terminals must be "maintenance free". Thanks to the energy saving means implemented above, the consumption of the terminals will be such that a low power supply, such as a power supply using a small solar panel, will be sufficient (energy harvesting). 4. Exit gate [0104] The resolution of the problem of the exit gate (see above) is carried out simply according to an embodiment of the invention by defining an exit zone. Figure 6 shows an example of use of the exit portal. The dog is allowed to circulate in zone Z1. Anchors A1, A2, A3 illustrate a typical example of terminal placement. The house (or shelter) M1 is accessible to the dog if the door P1 is open. Access to the P1 door is through the Z2 zone.

The objective is to allow the dog to access the house M1 through the door P1 without causing a warning or stimulation. After defining the zone Z1 in which the dog is allowed to circulate, the user defines a portal area where he wants to allow the dog to enter and exit. Zones Z1 and Z2 are defined by the means described above.

This embodiment of the invention comprises the following steps: 1. The dog is located according to the locating means described in the "Location" section. 2. The position (inclusion or not) of the dog with respect to zones Z1 and Z2 is determined according to a method known to those skilled in the art. 3. If the dog is in zone Z2, the warning and stimulation system is disabled regardless of the future position of the dog. 4. If the dog is not in zone Z2 but in zone Z1, the warning and stimulation system is reactivated even if it had previously been deactivated.

Thus, when the dog passes through zone Z2, the system is deactivated and allows the dog to leave the zone. He will be able to enter it again and as soon as he enters the zone Z1, the system will be reactivated and will again prevent him from leaving zone Z1. 5. Prohibited internal areas [0108] When a garden has flowerbeds, it is often preferable to prevent the dog from approaching it. By the means described above, it is easy to define a border around the parterre. If the dog approaches or enters the area defined by this boundary, the behavior is identical to the behavior towards the outer boundary and the goal is reached. 6. Behavior at the Border and Outside the Area The proposed locating system according to the invention makes it possible to locate the dog beyond the zone in which it is authorized to circulate. This feature solves problems with the state of the art.

Recall that, according to the invention, the position of the dog is determined, its presence or not in the authorized area is known and the distance to the border. Based on the evolution of the measure of distance from the border over time, it is easy to determine whether the dog is moving away from the border.

On the basis of the information above, and in order to educate the dog and push him back into the authorized area, it is important that the invention causes consistent behavior contrary to what is done in the state of the technique. It is proposed according to the invention to apply an increasing stimulation when the dog moves away from the authorized zone but to stop the stimulation immediately when approaching the authorized zone.

Figure 7 shows the principle of adaptation of the coercive level to push the dog back into the authorized area.

[0113] The coercive level is determined on a scale of 0 to 100%. Below 50%, it is a warning (sound or vibratory). Above 50% it is a stimulation (electrical or ultrasound). There are two scenarios: - in an authorized zone, when the dog approaches the border, the warning level increases linearly. As it moves away, the level decreases. The coercive level remains confined within a range of 0 and 50%. - In a forbidden zone, the level of stimulation increases according to a linear law up to a maximum level of 100% as the dog moves away from the border. On the other hand, when the dog approaches again the border after having left it, the level passes immediately to 50% (thus no stimulation). Thus, the dog will avoid a stimulation as soon as he returns to the authorized zone or will be inclined to return to it. On the other hand, if he tries to move away again, the coercive level will immediately pass to the level prescribed by the linear law, which corresponds to a stimulation.

When the dog is outside the authorized area, it is provided, according to one embodiment of the invention, to engage a GPS and a GSM module installed in the collar and send an SMS the owner to report the dog's escape. The owner will then be able to send a position request SMS to which the collar will respond with an SMS confirming the dog's current position.

In any case, the central unit will regularly receive (for example every 8 seconds) the GPS coordinates of the dog so as to allow the owner to find it if it is not out of range of the radio communication channel which connects the collar of the dog to the central unit.

It is known that GPS and GSM are energy hungry. This is not a problem, however, because they are activated only when the dog runs away and in order to find it quickly and easily.

According to one embodiment of the invention, the SMS communication can advantageously be replaced by the GPRS / 3G system for the purpose of directly locating the dog via an application for smartphone and / or PC. 7. Electrical warnings and stimulations [0118] As an optional feature, the invention proposes to use, in addition, the stimulation means according to the known principles of documents EP 1 968 359 and EP 2 365 738. 8. Protection against theft [0119 According to one embodiment of the invention, each radio communication frame will be identified by a unique identifier, typically a number encoded on 4 bytes. Only the collars, reference terminals and CPU configured for this unique identifier will be able to communicate with each other.

[0120] This unique identifier will be registered in the central unit during manufacture. The serial number could be used for this purpose for example.

Each terminal and each collar will be delivered with a paper certificate including a code (typically 4 or 6 digits). This code could advantageously be indicated on the invoice or on a detachable label glued to the collar or the terminals. This code will be registered electronically within each terminal or collar but will be inaccessible to the user.

When adding or replacing a collar or a terminal, the user will have, by means of a keyboard of the central unit, introduce the codes of the elements he wishes to see operate. with his system. The central unit will then transmit its unique identifier along with these codes to all elements.

Each collar or terminal will agree to operate in the system and therefore with the new unique identifier provided that the code sent corresponds to its internal code.

Thus, if a collar or a terminal is stolen, it will be impossible for the thief to use it with another CPU because it will not be in possession of the necessary code.

The system described above makes it possible to locate a tag in a defined area and advantageously replaces the buried wire border system. However, existing systems, such as automatic mowers for example, using buried wire can advantageously benefit from the proposed system with appropriate adaptation. The advantage of the proposed location is to know at any time the position of the mower and thus guide the mower to places where it has not passed for a long time thus ensuring a uniform mowing of the entire grass.

Glossary UWB (ultra-wideband signal): Broadband signal (over 100 MHz standardized by IEEE Std 802.15.4a - 2007). RTLS: real-time location system. anchor (anchor, beacon, reference terminal, fixed terminal): a fixed or mobile object used as a reference to locate another object. The position of the anchor is known in a reference X, Y. tag (mobile, collar): fixed or moving object whose position one wants to know. forbidden zone: zone in which the dog can not go. Stimulation is administered to the dog when he enters this area. authorized zone (authorized enclosure): zone in which the dog can circulate freely. He is nevertheless warned when he approaches too close to the border of the zone. boundary: the perimeter of an authorized zone or a prohibited zone (when it is a prohibited zone included in an authorized zone). reference terminal: see anchor. collar: electronic device carried by the dog, which can be located, able to communicate with the central unit and the reference terminals, capable of stimulating the dog and equipped with a GSM / GPS module. See also tag. central unit: a mains-powered device intended to be placed in a dwelling and responsible for the orchestration of the entire system. The central unit is also equipped with a keyboard and a screen to allow the user to configure and check his system. The central unit communicates with all elements of the system via the radio channel (ISM). warning: signal sent to the dog to warn him that he is breaking a rule and risking stimulation if he persists in his behavior. stimulation: signal sent to the dog in order to modify his behavior. Stimulation is more coercive than a warning.

Claims (17)

Virtual enclosure system for the confinement of an animal (1) in a confinement zone constituted by an authorized zone (7) separated from a forbidden zone (8) by a boundary (2), comprising: a plurality fixed reference terminals called anchors (3) distributed in said confinement zone and a central unit (4), said anchors (3) communicating bidirectionally with each other and with the central unit (4), and capable of measuring the distance separating them from each other with a precision at least equal to a predetermined value, the central unit (4) being able to establish a two-dimensional mark or XY, that is to say to assign a position to at least two anchors (10, 20, 30) and then locate the other anchors (40, ...) in this XY frame by a trilateration or probability estimation method by vote; at least one mobile electronic device comprising a transceiver, called a tag or collar (6), carried by the animal (1) and capable of communicating bi-directionally with the central unit (4), as well as measuring by trilateration the distance separating it from each of the anchors (3), said tag (6) being provided with means of warning and stimulation of the animal (1) operable by the central unit (4), to warn the animal (1) ) when the animal is approaching the boundary (2) in the authorized zone (7) and to stimulate the animal (1) when the animal crosses the border (2) or moves away from it (2) prohibited area (8); - Tracing means (5) of the boundary (2) between the authorized zone (7) and the forbidden zone (8) from the position of the anchors (3) once located in the aforementioned XY mark. 2. System according to claim 1, characterized in that the central unit (4) is provided with a controller and input / output means comprising pushbuttons and a screen, preferably a touch screen. 3. Protection system according to claim 1, characterized in that the bidirectional communication means equipping the tag (6), the anchors (3) and the central unit (4) are equipped with conventional ISM or broadband radio transmitters. UWB and / or ultrasonic transducers with a time of flight measurement method. 4. Protection system according to claim 1, characterized in that the warning means are acoustic and / or vibratory means and the stimulation means are means for applying a high voltage pulse. 5. System according to claim 1, characterized in that the predetermined value of precision on the determination of the distance, separating the anchors (3) between them, is 50 cm, preferably 10 cm. 6. System according to claim 3, wherein the position calculation from distances anchors (3) - tag (6) is deported to the central unit (4), said central unit (4) performing a position interrogation to fixed periodicity, which makes it possible to activate the anchors (3) and the tag (6) only during a short time interval with respect to the interrogation period, this time interval being preferably of the order of 5% of said periodicity. 7. System according to claim 6, characterized in that the communication between the central unit (4), on the one hand, and the anchors (3) and the tag (6) on the other, is carried out by means of a dedicated ISM radio channel. 8. System according to claim 1, characterized in that the tag (6) and the anchors (3) are powered by rechargeable battery, the anchors (3) being further equipped with a small photovoltaic panel. 9. System according to claim 1, characterized in that the tag (6) is equipped with a motion detector in the form of an accelerometer for indicating to the central unit (4) that the tag (6) is remained stationary since the last positioning and thus to avoid the implementation of a position interrogation by the central unit (4). 10. System according to claim 1, characterized in that the tag (6) is provided with a GPS and a GSM module allowing the owner of the animal to locate the animal by SMS exchange, especially when the animal fled after leaving the authorized area. 11. System according to claim 1, characterized in that the functionalities of the central unit (4) and / or the tracing means (5) of the boundary (2) are incorporated in the collar (6). 12. A method of implementing the animal containment system (1) by means of a virtual fence in a confinement zone, according to any one of the preceding claims, characterized by at least the following steps: installs the plurality of anchors (3) arbitrarily in said containment zone; the central unit (4) interrogates the plurality of anchor terminals (3) and determines the distances separating them from each other as well as the distance separating them from the central unit (4); the central unit (4) establishes a two-dimensional reference reference mark or XY which will be used for locating the animal (1); a closed boundary (2) of the confinement zone is determined, said closed boundary (2) being defined as being a polygon, that is to say a set of points or vertices connected by straight line segments or sides; - In operation, is provided with a collar or tag (6) an animal (1) brought to be in the confinement zone; the central unit (4) periodically interrogates the tag (6), determines its position in the XY coordinate system and assigns each of these tag positions (6) a location either in the authorized zone (7) or in the zone prohibited (8); if the tag (6) is in the authorized zone (7) and approaches the border (2), the central unit (4) activates the warning means associated with said tag (6) and if the tag ( 6) crosses the border (2) or is in the forbidden zone (8) and moves away from the border (2), the central unit (4) activates the stimulation means associated with said tag (6). 13. Method according to claim 12, characterized in that the boundary (2) is determined: either by using a location of the anchors (3) in the XY mark displayed on a touch screen associated with the central unit (4) and drawing said boundary (2) on the touch screen in the form of the aforementioned polygon; or by using a device called tracer (5) which communicates with the central unit (4) and the reference terminals (3), the central unit (4) periodically interrogating the tracer (5) when it is moved in the zone and asking for the respective distances separating it from the reference terminals (3), which enables the central unit (4) to determine the successive positions of the plotter in the XY coordinate system and to create the border (2) by joining these positions by line segments to create the aforementioned polygon. 14. The method of claim 12, characterized in that the XY mark is established in the following manner by the central unit (4): a first anchor (10) is assigned arbitrarily to the coordinate (0, 0); a second anchor (20) at a distance d is assigned to the coordinate (d, 0); a third anchor (30) is located from the two aforementioned anchors (10, 20) using the intersection of two circles from the respective distances of the third anchor (30) from the two aforementioned anchors (10, 20) one of the two possible intersections arbitrarily chosen as the position of the third anchor (30); the following anchors (40, ...) are located from the first three anchors (10, 20, 30) using a trilateration algorithm. 15. Method according to claim 12, in which the determination of the position of a tag T is carried out using two anchors of known position A1 and A2, separated respectively by T by distances d1 and d2, the tag T at the intersection of circles respectively centered at A1 and A2 and respective radii d1 and d2, two positions being possible, denoted Ta and Tb, characterized in that the most probable position of Ta and Tb is determined in proceeding by vote according to at least the following five successive steps: - initially 0 points are assigned to the two positions Ta and Tb; at least one other anchor A3, different from A1 and A2, the measured distance d3 of which is separated from the tag T, is selected, the respective distances d3a and d3b are calculated between A3 and the two potential positions Ta and Tb of tag T, we assign 3 additional points to the position Ta or Tb whose distance from the anchor A1 or A2 is the closest to d3 and we do not assign any point to the other position, that is to say say o if | d3 - d3a | <| d3 - d3b | => 3 additional points awarded Ta; o else => 3 additional points attributed to Tb; the previous position, preferably the position of the tag T determined during a previous interrogation by the central unit (4), is voted on, the Euclidean distance between this previous position and each of the positions Ta and Tb being known, 2 points additional being assigned to the position which has the smallest distance from the previous position; - We vote against at least one other anchor A3 whose distance is unknown, that is to say such that the distance measurement between the T tag and the aforementioned A3 anchor failed, because of the large distance separating the T-tag from the anchor A3 or because of an imposing obstacle, assigning 1 point to the furthest position from the anchor A3, ie: o if d3a> d3b => 1 additional point attributed to Ta; o else => 1 additional point attributed to Tb; - Of the 2 positions Ta and Tb, the one that has accumulated the most points in the previous steps is selected as the most probable position of the tag T. 16. The method of claim 12, for the case where a house M1, provided with a door P1, is accessible to the animal (1), access to the door P1 is passing through a zone Z2, called gate area, separating the dwelling M1 Z1 area where the animal is allowed to circulate, characterized in that it further comprises the following steps: - after location, the position of the animal (1), c that is, whether or not it is included in the zone Z1 or Z2 is determined; if the animal is in zone Z2, the warning and stimulation system is deactivated whatever the future position of the animal; if the animal is not in zone Z2 but in zone Z1, the warning and stimulation system is reactivated if it had previously been deactivated. 17. A method according to claim 12, characterized in that a coercive level scale ranging from 0 to 100% is applied so as to push the animal (1) to return to the authorized zone (7) when it leaves the to go to the forbidden zone (8), a coercive level of 50% corresponding to the value below which a warning is communicated to the animal (1) and above which stimulation is communicated to him, characterized by the following steps: - in the authorized zone (7), when the animal (1) approaches, respectively moves away from the border (2), the warning level increases, respectively decreases linearly, the coercive level being less than or equal to 50%; - in forbidden zone (8), the level of stimulation increases according to a linear law up to a maximum level of 100% as the animal moves away from the border; - In forbidden zone (8), when the animal gets closer to the border (2) after having moved away from it, the level immediately goes to 50%, thus with suppression of stimulation.