Patent Application
20230408293
The present invention belongs to the general field of the navigation in a geographical area. It more particularly relates to a method for determining a graph modeling a geographical area as well as a method for navigating in the area by means of said graph. It also relates, in particular, to a navigation system configured to implement said navigation method. The invention finds a particularly advantageous application, although without limitation, when the geographical area considered is situated in a closed environment (called indoor geographical area).
The navigation within a geographical area can be defined as being the combination of localization techniques and route search.
With regard to the localization, it is about being able to determine the position(s) occupied by an object or a person during a movement within said area. For this purpose, a position is for example determined in absolute terms (i.e. the geographical coordinates associated with said position are determined in a given reference frame). A position can also be determined relatively with respect to the environment in which the object or the person whose position is sought is located (for example, a relative position can be obtained by determining distances separating the object or the person in question of fixed elements positioned in said environment).
The route search techniques, for their part, aim to orient the object or the person wishing to move in the geographical area in order to reach a targeted location. It is therefore about determining one or several paths to follow in order to join said targeted location. The determination of such paths is based in particular on the location of said object or said person.
Conventionally, the navigation in a geographical area situated in an open environment (i.e. in a non-partitioned environment) is done using the Global Positioning System or GPS. In this way, it is possible to access the two-dimensional coordinates (latitude, longitude) of an object or an equipped person, which in fine allows determining one or several routes to follow on a map established in accordance with the coordinate system considered.
However, the use of the GPS system cannot be envisaged with regard to the navigation in a geographical area situated inside a closed environment. Indeed, in a closed environment, the GPS system suffers from irregular connectivity linked to the presence of different rooms separated from each other by walls, doors, stairs, etc. Moreover, the GPS system proves to be unsuitable for the closed environments for which it is important to take into account an additional dimension of space linked to the presence of floors, stairs, etc.
Solutions have therefore been proposed to circumvent this inability to exploit the GPS system for the navigation in a closed environment. Thus, it has in particular been proposed to use RFID (Radio Frequency IDentification) technology.
More particularly, it is firstly about affixing electronic chips, also called radio tags, in different places of an area of a closed environment (for example on walls, on objects, etc.). Then, secondly, it is about manually taking a reading of the coordinates respectively associated with the places in which said radio tags have been affixed. Finally, when a user tries to move in said area, he takes an RFID reader able to identify, in a manner known per se, the radio tags, and to determine the position of said RFID reader from the identifiers of the radio tags as well as their respective coordinates. Knowing his position, said user can therefore locate himself in said area and thus move therearound. For more details on the use of the RFID technology for the navigation in an area of a closed environment, it is possible to consult the following document: “Accurate Self-Localization in RFID Tag Information Grids Using FIR Filtering”, J. J. Pomarico-Franquiz, Y. S. Shmaliy, IEEE Transactions on Industrial Informatics, vol. 10, no. 2, pp. 1317-1326, Mai 2014.
Although the RFID technology has the advantage of being passive (i.e. a radio tag does not need to be connected to an energy source to operate), its implementation for the navigation in an area of an open or closed environment encounters certain limitations. It is indeed necessary to deploy specific hardware (RFID reader, RFID tags), which makes it a complex and expensive solution. Moreover, it is also necessary to read the (absolute) coordinates of the radio tags deployed, which is particularly tedious and time-consuming.
The present invention aims to overcome all or part of the drawbacks of the prior art, in particular those set out above, by proposing a solution that allows navigating in a geographical area, particularly in a geographical area situated in a closed environment, more efficiently than the solutions of the prior art. By “more efficient navigation”, reference is made here to a navigation whose implementation is simple, inexpensive and rapid.
To this end, and according to a first aspect, the invention relates to a method for determining a graph modeling a geographical area, said area including at least one transmitter device configured to backscatter towards a receiver device an ambient signal emitted by an emitter device so as to be detected by said receiver device. Said method includes steps of:
According to a second aspect, the invention relates to a method for receiving one or several signals in a geographical area, said area including at least one transmitter device configured to backscatter towards a receiver device an ambient signal emitted by an emitter device so as to be detected by said receiver device. Said method includes steps of:
According to a third aspect, the invention relates to a method for determining at least one footprint of a geographical area, said area including at least one transmitter device configured to backscatter towards a receiver device an ambient signal emitted by an emitter device so as to be detected by said receiver device. Said method includes, for at least one location of said area occupied by the receiver device, steps of:
According to a fourth aspect, the invention relates to a method for determining a path, called “intermediate path”, in a geographical area, said area including at least one transmitter device configured to backscatter towards a receiver device an ambient signal emitted by an emitter device so as to be detected by said receiver device, said intermediate path being configured to connect a starting location to a neighborhood of a given transmitter device, called “target transmitter device”, among said at least one transmitter device. Said method includes steps of:
In particular modes of implementation, the intermediate path is determined by means of the Dijkstra algorithm.
According to a fifth aspect, the invention relates to a method for moving in a geographical area, said area including at least one transmitter device configured to backscatter towards a receiver device an ambient signal emitted by an emitter device so as to be detected by said receiver device, said receiver device being intended to connect a starting location to a neighborhood of a given transmitter device among said at least one transmitter device. Said method includes steps of:
According to a sixth aspect, the invention relates to a method for determining a location, called “intermediate location”, in a geographical area, said area including at least one transmitter device configured to backscatter towards a receiver device an ambient signal emitted by an emitter device so as to be detected by said receiver device, said receiver device being intended to connect a starting location to a neighborhood of a given transmitter device among said at least one transmitter device. Said method including steps of:
According to a seventh aspect, the invention relates to a method for navigating in a geographical area, said area including at least one transmitter device configured to backscatter towards a receiver device an ambient signal emitted by an emitter device so as to be detected by said receiver device. Said method includes a set of steps of:
Thus, the implementation of the different methods according to the invention, and particularly of said navigation method, is based on the use of an ambient backscatter communication technology, which is energy efficient and particularly simple to deploy.
Indeed, the use of this ambient backscatter technology does not require the deployment of specific hardware elements for its implementation, with the exception of one or several transmitter devices able to backscatter an ambient signal. Therefore, the invention allows envisaging the situation in which an ambient signal is emitted by a hardware element already present in the geographical area, such as a base station for example. In the same way, a signal backscattered by a transmitter device can be received by a hardware element already present in the geographical area, such as for example a cellular telephone.
It is further understood that the fact of using the ambient backscatter communication technology advantageously allows dispensing with the use of GPS signals, so that the invention is particularly well suited to the navigation in a geographical area situated in a closed environment.
The navigation solution proposed by the invention further differs fundamentally from the prior art in that it does not require knowing the coordinates of the transmitter device(s) deployed in the geographical area. The invention is indeed based on a graph formed of footprints, a footprint being attached to the detection (by ambient backscatter) of transmitter devices of said geographical area. However, there is no need to know the coordinates of transmitter devices thus detected to form footprints, and therefore in fine the graph from which it is possible to build a navigation route (this route being built progressively with the implementation of the navigation method, via the first footprints belonging to the determined intermediate paths). It follows from these provisions that the implementation of the invention is quick (consumes little time) and easy.
In particular modes of implementation of the moving method and/or of the navigation method, said neighborhood criterion is satisfied if the receiver device reaches a location at which is situated a given or any transmitter device among the transmitter devices belonging to said locating set.
In particular modes of implementation of the navigation method, said set of steps also includes a step of determining an intermediate location according to a method for determining an intermediate location in accordance with the invention.
According to an eighth aspect, the invention relates to a computer program including instructions for the implementation of any one of the methods according to the invention when said computer program is executed by a computer.
This program can use any programming language, and be in the form of source code, object code or intermediate code between source code and object code, such as in partially compiled form or in any other desirable form.
According to a ninth aspect, the invention relates to a computer-readable information or recording medium on which a computer program according to the invention is recorded.
The information or recording medium can be any entity or a device capable of storing the program. For example, the medium can include a storage means, such as a ROM, for example a CD ROM or a microelectronic circuit ROM, or a magnetic recording means, for example a floppy disk or a hard disk.
On the other hand, the information or recording medium can be a transmissible medium such as an electrical or optical signal, which can be conveyed via an electrical or optical cable, by radio or by other means. The program according to the invention can be particularly downloaded from an Internet-type network.
Alternatively, the information or recording medium can be an integrated circuit in which the program is incorporated, the circuit being adapted to execute or to be used in the execution of the method in question.
According to a tenth aspect, the invention relates to a device for determining a graph modeling a geographical area, said area including at least one transmitter device configured to backscatter towards a receiver device an ambient signal emitted by an emitter device so as to be detected by said receiver device. Said determination device includes:
According to an eleventh aspect, the invention relates to a device for receiving one or several signals in a geographical area, said area including at least one transmitter device configured to backscatter towards said receiver device an ambient signal emitted by an emitter device so as to be detected by said receiver device. Said receiver device includes a receiving module configured to receive one or several backscattered signals when, following a movement of said receiver device to reach at least one location of said area, said at least one location has been reached.
According to a twelfth aspect, the invention relates to a device for determining at least one footprint of a geographical area, said area including at least one transmitter device configured to backscatter towards a receiver device an ambient signal emitted by an emitter device so as to be detected by said receiver device. Said determination device includes a determination module configured to determine a data identifying, among said at least one transmitter device, the transmitter device(s) detected by the receiver device when said receiver device occupies at least one location of said area, said data corresponding to a footprint of the geographical area for said at least one location.
According to a thirteenth aspect, the invention relates to a device for determining a path, called “intermediate path”, in a geographical area, said area including at least one transmitter device configured to backscatter towards a receiver device an ambient signal emitted by an emitter device so as to be detected by said receiver device, said intermediate path being configured to connect a starting location to a neighborhood of a given transmitter device, called “target transmitter device”, among said at least one transmitter device. Said determination device includes:
According to a fourteenth aspect, the invention relates to a device for receiving one or
several signals in a geographical area, said area including at least one transmitter device configured to backscatter towards said receiver device an ambient signal emitted by an emitter device so as to be detected by said receiver device. Said receiver device is intended to connect a starting location to a neighborhood of a given transmitter device among said at least one transmitter device, and includes:
According to a fifteenth aspect, the invention relates to a device for determining a location, called “intermediate location”, in a geographical area, said area including at least one transmitter device configured to backscatter towards a receiver device an ambient signal emitted by an emitter device so as to be detected by said receiver device, said receiver device being intended to connect a starting location to a neighborhood of a given transmitter device among said at least one transmitter device. Said determination device includes:
According to a sixteenth aspect, the invention relates to a system for navigating in a geographical area, said area including at least one transmitter device configured to backscatter towards a receiver device an ambient signal emitted by an emitter device so as to be detected by said receiver device. Said system includes a device for determining a graph according to the invention, a device for receiving one or several signals according to the invention, a device for determining at least one footprint according to the invention, a device for determining a intermediate path according to the invention as well as a device for receiving one or several signals and intended to connect a starting location to a neighborhood of a given transmitter device among said at least one transmitter device according to the invention.
In particular embodiments, said system further including a device for determining an intermediate location according to the invention.
Other characteristics and advantages of the present invention will become apparent from the description given below, with reference to the appended drawings which illustrate one exemplary embodiment without any limitation. On the figures:
For the following description, it is considered without limitation that the navigation able to be implemented by means of said navigation system 10 corresponds to a navigation in a geographical area Z situated in a closed environment (“indoor area”). For example, said area corresponds to a space situated in a hangar, a building, a personal dwelling, etc. In general, no limitation is attached to the closed environment that can be considered in the context of the present invention.
It is moreover important to note that the invention is not limited to the navigation in a geographical area situated in a closed environment. Indeed, the invention is also applicable to the case of a geographical area situated in an open environment (i.e. a non-partitioned environment).
In accordance with the invention, the navigation system 10 is configured to carry out processing operations making it possible to navigate within said area Z. These processing operations are carried out by the navigation system 10 in two phases, namely a navigation preparation phase and another phase of actual navigation in the area Z.
In its general principle, said first phase consists in determining a graph G modeling the area Z. Said graph G corresponds to an abstract representation of the area Z which can be assimilated to a mapping of the latter. Said graph G is intended to be used for the execution of the processing operations attached to said second phase which consists, for its part, in allowing the actual navigation in the area Z.
The aspects of the invention are firstly described in connection with the processing operations carried out during said navigation preparation phase.
In the embodiment illustrated in
By “radio signal”, reference is made here to an electromagnetic wave propagating by non-wired means, whose frequencies are comprised in the traditional spectrum of the radioelectric waves (from a few hertz to several hundred gigahertz).
By way of non-limiting example, the ambient signal is a 4G mobile telephone signal emitted in the emission band [811 MHz, 821 MHz] by the emitter device D1. It should however be specified that the invention remains applicable to other types of radio signals, such as for example a mobile telephone signal other than 4G (for example 2G, 3G, 5G), a Wi-Fi signal, etc. In general, no limitation is attached to the ambient radio signal that can be considered in the context of the present invention as long as the latter can be used to communicate by ambient backscatter as described below.
In the embodiment of
For the following description, it is considered without limitation that the emitter device D1 is a base station. It is also considered that the receiver device D2 is a mobile terminal of the cellular telephone type, for example a smartphone, belonging to a user U1 and henceforth called “mapping terminal”.
It should however be noted that no limitation is attached to the forms respectively taken by the emitter D1 and receiver D2 devices, provided that they are able to communicate with each other within a wireless communication network (here in the emission band). Thus, according to another example, the emitter device D1 can correspond to a Wi-Fi hotspot, and the receiver device D2 can correspond to a smartphone, or a touch pad, or a personal digital assistant, or a personal computer, etc., able to communicate according to the Wi-Fi protocol.
In the embodiment of
For the following description, it is considered without limitation that said transmitter devices T are fixed in the area Z (i.e. the respective positions of the transmitter devices T are invariant over time), for example by being affixed to fixed objects disposed in the area Z and/or by being affixed to elements (wall, door, stairs, etc.) forming the local structure of the closed environment comprising the area Z.
The choice according to which the transmitter devices T are fixed is however just a variant of embodiment of the invention, and nothing excludes envisaging that all or part of the transmitter devices are mobile, for example by being affixed to objects able to move in the area Z. Moreover, no limitation is attached to the number of transmitter devices that can be considered in the present invention. Preferably, the number of transmitter devices present in the area Z is greater than or equal to 3. However, nothing excludes envisaging a number less than 3 or even the case where a single transmitter device is present in the area Z. In general, those skilled in the art are able to adapt the following description to the different cases mentioned above (mobile transmitter device, single transmitter device in the area Z).
As mentioned above, each transmitter device T is configured to transmit to the mapping terminal D2 a signal, called “backscattered signal”, by ambient backscatter of the ambient signal emitted by the base station D1. Said backscattered signal conventionally carries a message which, in the context of the present invention, includes a data for identifying said transmitter device T. In this way, each transmitter device T can be detected by the mapping terminal D2.
No limitation is attached to the nature of an identification data associated with a transmitter device T, provided that it allows distinguishing said transmitter device from the other transmitter devices arranged in the area Z. For example, each identification data can correspond to an alphanumeric identifier.
The transmission of the backscattered signal by a transmitter device T is performed by variation of the backscattering of the ambient signal, this variation relying on the possibility for the transmitter device T to modify the impedance presented to an antenna that equips it (not represented in the figures), depending on the identification data to be transmitted.
More specifically, each transmitter device T can be associated with operating states depending on the impedance presented to the antenna with which it is equipped. For the following description, it is considered without limitation that these states are a state called “backscatter” state (the transmitter device T can backscatter the ambient signal), as well as a contrary state called “non-backscattering” state (the transmitter device T cannot backscatter the ambient signal or, in other words, is “transparent” to the ambient signal). The impedance associated with the backscattering state typically corresponds to zero or infinite impedance, whereas the impedance associated with the non-backscattering state typically corresponds to the conjugate complex of the characteristic impedance of the antenna in the considered propagation medium and at the considered frequency.
It is important to note that the invention is not limited to this ideal case in which only two states respectively perfectly backscattering and perfectly non-backscattering would be considered. Indeed, the invention also remains applicable in the case where two states (first state and second state) are not perfectly backscattering/non-backscattering, provided that the variation of the backscattered waves is perceptible by the mapping terminal D2 which is intended to receive the data for identifying a transmitter device T.
The identification data intended to be transmitted by a transmitter device T to the mapping terminal D2, by means of the backscattered signal, is conventionally encoded by means of a set of symbols, comprising for example a symbol called “high” symbol (bit of value “1”), or a symbol called “low” symbol (bit of value “0”). The transmission of the identification data by variation of the ambient backscatter can therefore be performed, in a manner known per se, by alternation between said backscattering and non-backscattering states, each of said states being dedicated to the transmission of a symbol of a particular type (for example high symbol for the backscattering state and low symbol for the non-backscattering state, or vice versa). In other words, an identification data intended to be transmitted by a transmitter device T is transported to the mapping terminal D2 by modulation of the waves of the ambient signal (i.e. by retromodulation).
The processing operations aimed at backscattering said ambient signal are conventionally carried out by each of said transmitter devices T by implementing a backscattering method (not represented in the figures). To this end, each transmitter device T includes for example one or several processors and storage means (magnetic hard disk, electronic memory, optical disk, etc.) in which data and a computer program are stored in the form of a set of program code instructions to be executed to implement said backscattering method.
Alternatively or additionally, each transmitter device T also includes one or several programmable logic circuit(s), of the FPGA, PLD, etc. type, and/or specific integrated circuits (ASIC), and/or a set of discrete electronic components, etc. adapted to implement the backscattering method.
In other words, each transmitter device T includes a set of means configured by software (specific computer program) and/or hardware (FPGA, PLD, ASIC, etc.) to implement the backscattering method.
The mapping terminal D2 is, for its part, further configured to carry out processing operations aimed at decoding the signals backscattered by the transmitter devices T, so as to obtain the respective data for identifying said transmitter devices T. Each identification data is obtained by implementing a decoding method (not represented in the figures). It is noted that the decoding of the backscattered signals in fine allows detecting one or several transmitter devices T.
For this purpose, the mapping terminal D2 includes for example one or several processors and storage means (magnetic hard disk, electronic memory, optical disk, etc.) in which data and a computer program are stored in the form of a set of program code instructions to be executed to implement said decoding method.
Alternatively or additionally, the mapping terminal D2 also includes one or several programmable logic circuits, of the FPGA, PLD, etc. type, and/or specific integrated circuits (ASIC), and/or a set of discrete electronic components, etc. adapted to implement the decoding method.
In other words, the mapping terminal D2 includes a set of means configured by software (specific computer program) and/or hardware (FPGA, PLD, ASIC, etc.) to implement the decoding method.
The specific aspects concerning the signal processing techniques for the transmission of data by ambient backscatter as well as the decoding of these data are known and for example detailed in the following document to which those skilled in the art can refer: “Ambient Backscatter Communications: A Contemporary Survey”, N. Van Huynh, D. Thai Hoang, X. Lu, D. Niyato, P. Wang, D. In Kim, IEEE Communications Surveys & Tutorials, vol. 20, no. 4, pp. 2889-2922, Fourth quarter 2018.
Particularly, it is known that the possibility of transmitting data by ambient backscatter by a transmitter device T depends on its remoteness from the source of the ambient signal, i.e. the base station D1. It is also known that the possibility of decoding a signal backscattered by the mapping terminal D2 depends on its remoteness from the emitter device at the origin of said backscattered signal. Ultimately, these provisions involve that all the transmitter devices T are not necessarily detected at the same time when the base station D1 emits the ambient signal. These aspects are described in more detail below.
It is also noted that, conventionally with regard to the ambient backscatter communication technology, the base station D1, the mapping terminal D2 and all the transmitter devices T are distinct from each other.
In the context of the navigation preparation phase, and according to the embodiment of
According to one exemplary embodiment, the locations POS_1, . . . , POS_P correspond to given locations of the area Z. For this purpose, said locations POS_1, . . . , POS_P can for example be visually reported in the closed environment, so that the user U1 in possession of the mapping terminal D2 can move in the area Z so as to successively reach said locations POS_1, . . . , POS_P.
According to another example, the locations POS_1, . . . . , POS_P are not previously indicated in the area Z, and correspond to stopping points for the user U1 in possession of the mapping terminal D2 when he moves in the area Z. These stopping points are for example entirely random or even linked to sub-areas of interest for said user U1 within said area Z.
Whether the locations POS_1, . . . . , POS_P correspond to given locations or not, no limitation is attached to the way in which said locations POS_1, . . . . , POS_P are distributed within the area Z. Preferably, said locations POS_1, . . . . , POS_P are distributed in a substantially uniform manner in the area Z, so as to promote the detection of a maximum of transmitter devices T by the mapping terminal D2.
Although a plurality of locations POS_1, . . . . , POS_P are considered in the embodiment of
For the following description, it is now considered that said locations POS_1, . . . . , POS_P correspond to given locations of the area Z.
As illustrated in
The read only memory D2_3 of the mapping terminal D2 constitutes a recording medium in accordance with the invention, readable by the processor D2_1 and on which a computer program PROG_D2_1 in accordance with the invention is recorded, including instructions for the execution of steps of the receiving method according to the invention. The program PROG_D2_1 defines at least one functional module of the mapping terminal D2, which is based on or controls the hardware elements D2_1 to D2_5 of the mapping terminal D2 mentioned above, and which in particular comprises a receiving module MOD_RX_D2 configured to receive one or several backscattered signals when, following a movement of said mapping terminal D2 to reach a location POS_i among said plurality of locations POS_1, . . . . , POS_P, said at least one location POS_i has been reached.
The communication module D2_5 in particular allows the mapping terminal D2 to communicate with the base station D1, for example to exchange data via the wireless communication network. Said communication module D2_5 in particular integrates the receiving module MOD_RX_D2.
In the context of the navigation preparation phase, and according to the embodiment of
Each footprint EMP_i (i being an integer index comprised between 1 and P) is determined for a location POS_i of the area Z that the mapping terminal D2 occupies, the mapping terminal D2 moving between each position POS_i.
In accordance with the invention, each footprint EMP_i corresponds to a data identifying, among the transmitter devices T of the area Z, the transmitter device(s) detected by the mapping terminal D2 when said mapping terminal D2 occupies the location POS_i associated with said footprint EMP_i.
In other words, each footprint EMP_i determined by the mapping terminal D2 allows identifying the transmitter device(s) T illuminated by the base station D1 and whose generated backscattered signal(s) arrive, with a suitable power level, to the level of the mapping terminal D2 occupying said location POS_i,
It should be noted that in accordance with the principles of implementation of the ambient backscatter communication technology, the transmitter device(s) T likely to be detected by the mapping terminal D2 are situated at a distance of the order of one meter, even a few meters, from said mapping terminal D2.
For the following description, the convention according to which a footprint EMP_i is a data taking (numerically) the form of a vector of numbers is adopted. The components of this vector are respectively associated with the transmitter devices T situated in the area Z.
More particularly, to illustrate the form taken by such a vector, it is assumed that the number of transmitter devices T is equal to K, where K is an integer strictly greater than 1. It is further assumed that the transmitter devices are classified so that it is possible to assign to each transmitter device an index k comprised between 1 and K. Thus, the transmitter device with which the index k is associated is denoted T_k.
In other words, in accordance with the notations adopted here without limitation, the vector representing the footprint EMP_i is written: [EMP_i(1), EMP(2), . . . EMP_i(k), . . . , EMP_i(K)], the component EMP_i(k) being associated with the transmitter device T_k, and indicating whether said transmitter device T_k is detected by the mapping terminal D2 when the base station D1 emits the ambient signal and said mapping terminal D2 occupies the location POS_i associated with said footprint EMP_i. For the following description, it is also considered that a component EMP_i(k) of a footprint EMP_i can take two distinct values: either the value 0 indicating an absence of detection of the transmitter device T_k, or the value 1 indicating a detection of the transmitter device T_k.
It should be noted that, for the purpose of simplifying the description, the notation “T_k” is only used to designate a particular transmitter device among all the transmitter devices situated in the area Z. Otherwise, and as already done before, the notion “T” is used to designate any one or several transmitter devices among all the transmitter devices situated in the area Z.
As illustrated in
In addition to the emitter D1 and receiver D2 devices, and as illustrated by
As illustrated in
The read only memory D3_3 of the mapper D3 constitutes a recording medium in accordance with the invention, readable by the processor D3_1 and on which a computer program PROG_D3 in accordance with the invention is recorded, including instructions for the execution of steps of the method for determining the graph G according to the invention. The program PROG_D3 defines functional modules of the mapper D3, which are based on or control the hardware elements D3_1 to D3_5 of the mapper D3 mentioned above, and which comprise in particular:
Thus, and said again otherwise, two vertices EMP_i, . . . , EMP_j (i and j being distinct indices) of the graph G are connected by an edge if there is an index k comprised between 1 and K (K being the number of transmitter devices situated in the area Z) such as: EMP_i(k)=EMPJ(k)=1.
The communication module D3_5 in particular allows the mapper D3 to communicate with the mapping terminal D2, for example via the wireless communication network used for the ambient backscatter, to receive the footprints EMP_1, . . . , EMP_P determined by said mapping terminal D2. Said communication module D3_5 in particular integrates the obtaining module MOD_OBT_D3 (the communication module D2_5 equipping the mapping terminal D2 is therefore in this case configured to transmit said footprints EMP_1, . . . , EMP_P to the mapper D3).
Nothing, of course, excludes envisaging that the footprints EMP_1, . . . , EMP_P, once determined by the mapping terminal D2, are firstly transmitted to a device, called “other device”, distinct from the mapper D3 and that, secondly, said mapper D3 obtains said footprints EMP_1, . . . , EMP_P from said other device. For example, said other device is a dedicated server including a database configured to store said footprints EMP_1, . . . , EMP_P.
In general, no limitation is attached to the way in which the mapper D3 can obtain the footprints EMP_1, . . . , EMP_P determined by the mapping terminal D2.
The method for receiving one or several backscattered signals (executed by the mapping terminal D2), the method for determining the footprints EMP_1, . . . , EMP_P (executed by the mapping terminal D2) as well as the method for determining the graph G (executed by the mapper D3) are all three implemented during the execution of a general method, called “navigation preparation” method. Said navigation preparation method therefore groups together said methods for receiving one or several backscattered signals, for determining footprints EMP_1, . . . , EMP_P and for determining the graph G, and includes, in particular, the processing operations implemented by the navigation system 10 during said navigation preparation phase.
Fiaure 4 represents, in the form of a flowchart, one particular embodiment of the navigation preparation method, as it is implemented, at least partly, by the mapping terminal D2 of
As illustrated in
This step E10[i] belongs to the receiving method and is carried out thanks to the user U1 in possession of the mapping terminal D2. For example, a map representative of the area Z as well as at least the location POS_i (all the locations POS_1, . . . . , POS_P that can be displayed at once, or in turns progressively with the movements of the user U1) are displayed, thanks to display means configured for this purpose, on a screen equipping the mapping terminal D2. Consequently, the user U1 can go to said location POS_i by consulting his screen, the position of said user U1 further being displayed on said screen.
Alternatively, or in combination with the previous example, said location POS_i can correspond to a remarkable location of the area Z. The user U1 is then able to reach the location POS_i from only a description of said location POS_i, so that it is unnecessary for it to be indicated on a map displayed on the screen of the mapping terminal D2. By “remarkable place”, reference is made here to a place that can be easily distinguished within the area Z insofar as no other place of the area Z looks like it.
Said navigation preparation method further includes, for each location POS_i of the area Z, a step E20[i] of receiving one or several backscattered signals when said location POS_i is reached by the mapping terminal D2. Said step E20[i] belongs to the receiving method and is implemented by the receiving module MOD_RX_D2 equipping the mapping terminal D2.
As illustrated in
Subsequently, the navigation preparation method includes a step E40[i] of determining the footprint EMP_i associated with said location POS_i. Said step E40[i] belongs to the footprint determination method and is implemented by the determination module MOD_DET_D2 equipping the mapping terminal D2.
According to one exemplary implementation of said step E30[i], the receipt of the backscattered signal(s) takes place for a given duration.
Alternatively, the receipt of the backscattered signal(s) takes place as long as the number of transmitter devices T detected by the mapping terminal D2 is below a given threshold, the duration of receipt of the backscattered signal(s) being further increased by a given time limit.
Steps E10[i], E20[i], E30[i] and E40[i] are iterated for each of the locations POS_1, . . . , POS_P, so that at the end of said iterations, the mapping terminal D2 has determined the P footprints EMP_1, . . . , EMP_P. Said footprints EMP_1, . . . , EMP_P are then transmitted to the mapper D3 during a step E50 implemented by the mapping terminal D2 by means of its communication module D2_5.
It should be noted that the order in which the locations POS_1, . . . . , POS_P are reached by the user U1 of the mapping terminal D2 is not a limiting factor of the invention. By way of example, and in order to minimize the traveled distance, the user U1 can join the location that seems to him to be closest to him and that he has not yet visited.
The navigation preparation method also includes a step E60 of obtaining the footprints EMP_1, . . . , EMP_P. Said step E60 belongs to the method for determining the graph G and is implemented by the obtaining module MOD_OBT_D3 equipping the mapper D3.
In practice, said obtaining step corresponds to receipt of the footprints EMP_1, . . . , EMP_P transmitted by the mapping terminal D2.
Then, the navigation preparation method includes a step E70 of determining the graph from the footprints EMP_1, . . . , EMP_P obtained. Said step E70 belongs to the method for determining the graph and is implemented by the determination module MOD_DET_D3 equipping the mapper D3.
Said step E70 includes particularly a sub-step (not represented in
It is noted that it was implicitly assumed, for the implementation of the navigation preparation method of
The choice according to which the base station D1 emits the ambient signal permanently is however just a variant of implementation of the invention. Indeed, it is also possible to envisage that the emission of the ambient signal takes place during given time frames. In this case, the mapping terminal D2 has knowledge of such frames so as to be able to coordinate its movements with said frames and thus occupy a location POS_i when the base station D1 is emitting.
According to yet another alternative, once the mapping terminal D2 occupies a location POS_i, it transmits to the base station D1 a pilot message warning it that said location POS_i has been reached, so that the base station D1 then emits the ambient signal.
One particular exemplary implementation of the navigation preparation method of
Said four
Sub-
It is noted that
Sub-
Furthermore, the different footprints determined once steps E10[i], E20[i], E30[i] and E40[i] have been iterated are also represented symbolically in sub-
Sub-
Finally, sub-
The aspects of the invention in connection with the processing operations carried out during the actual navigation phase in the area Z will now be described. Said navigation phase is based on the graph G determined during the navigation preparation phase.
In the context of said actual navigation phase, it is assumed that a user U2 of the navigation system 10 wishes to move in the area Z. It is noted that the user U2 wishing to move in the area Z can be either the same user U1 as the one described above as being in possession of the mapping terminal D2, or a distinct user.
In accordance with the invention, the user U2 wishes to reach, from a starting location POS_INI that he occupies, a given transmitter device, called target transmitter device “T_END”, among the transmitter devices T situated in said area Z. In other words, the user wishes to navigate in the area Z to make a route allowing him to connect his starting location POS_INI to said target transmitter device T_END.
It should be noted that the starting location POS_INI may or may not correspond to one of the locations POS_1, . . . . , POS_P used during the navigation preparation phase to determine the footprints EMP_1, . . . , EMP_P.
In its general principle, and with regard to said actual navigation phase, the navigation system 10 aims to indicate to the user U2 footprints EMP_i that he must successively join (it means reaching, for each footprint indicated to the user U2, a location satisfying a neighborhood criterion with some transmitter devices identified by said footprint) until finally reaching an arrival footprint identifying the transmitter device T_END. The location finally reached in association with such an arrival footprint constitutes, within the meaning of the invention, a neighborhood of said transmitter device T_END.
Once a location of said arrival footprint has been reached, it remains for the user U2 to move to definitively join the transmitter device T_END. To do so, and in accordance with the invention, each transmitter device T situated in the area Z is associated with one or several data, called “sensory data”, making it possible to identify in a sensory manner said transmitter device T in the environment of said area Z. It is important to note that the sensory data associated with a transmitter device T differ from the data for identifying this same transmitter device T which is transmitted to the mapping terminal D2 by ambient backscatter of the ambient signal during the navigation preparation phase.
By way of non-limiting example, a sensory data associated with a transmitter device T corresponds to any one of the following elements:
No limitation is attached to the number and nature of the sensory data associated with a transmitter device T. Thus, a transmitter device T can be associated with a single sensory data or with a plurality of sensory data of the same type (image, video, sound, etc.) but also of distinct respective types.
According to one exemplary embodiment, all or part of the sensory data respectively associated with the transmitter devices T of the area Z is stored in storage means external to the devices belonging to the navigation system 10. Said storage means correspond for example to a server including a database to which the different devices belonging to the navigation system 10 can have access.
Alternatively or additionally to the previous exemplary embodiment, all or part of the sensory data respectively associated with the transmitter devices of the area Z is stored in storage means belonging to one or several devices of the navigation system 10.
In the embodiment illustrated in
As illustrated in
The read only memory D4_3 of the tracker D4 constitutes a recording medium in accordance with the invention, readable by the processor D4_1 and on which a computer program PROG_D4 in accordance with the invention is recorded, including instructions for the execution of steps of the method for determining said intermediate path PATH_INT according to the invention. The program PROG_D4 defines functional modules of the tracker D4, which are based on or control the hardware elements D4_1 to D4_5 of the tracker D4 mentioned above, and which comprise in particular:
The communication module D4_5 in particular allows the tracker D4 to communicate with the mapper D3 as well as with said device D5, for example to exchange data via the wireless communication network. Said communication module D4_5 in particular integrates the first obtaining module MOD_OBT1_D4 and the second obtaining module MOD_OBT2_D4.
The determination of a path of minimum length in a graph involves algorithmic techniques known to those skilled in the art, and commonly grouped under the name “traveling salesman problem”. In general, any algorithm for determining a path of minimum length in a graph can be envisaged, and the choice of a particular algorithm only constitutes one variant of implementation of the invention. For example, the intermediate path is determined using the Dijkstra algorithm. Alternatively, other algorithms can be implemented, such as for example an algorithm of the Bellman-Ford Moore type or of the Roy-Warshall-Floyd type.
It is noted that the intermediate path PATH_INT corresponds to a sequence SEQ of footprints. There is therefore an order relation between the footprints of said sequence SEQ so that it is possible to refer to the “first footprint” of said sequence SEQ. More particularly, said order relation allows defining the order in which the footprints of the sequence SEQ are classified, it being understood that by following this order it is possible to connect the starting location POS_INI to a footprint identifying the transmitter device T_END.
Within the meaning of the present invention, the convention is adopted according to which the updated graph G_NEW corresponds to the graph G if said current footprint EMP_CUR already forms a footprint of said graph G (which corresponds to the case where the initial location POS_INI is sufficiently close, or even identical, to one of the locations POS_1, POS_P).
To make his route, and as illustrated in
In the present embodiment, the device D5 is distinct from the mapping terminal D2 and corresponds to a mobile terminal of the cellular telephone type, for example a smartphone. It should however be noted that, similarly to what has been described for the mapping terminal D2, no limitation is attached to the form taken by the device D5 provided that the latter is configured to receive one or several backscattered signals in a frequency band identical to the one used by the mapping terminal D2, as well as to carry out processing operations allowing the user in possession of said terminal D5 to navigate in the area Z, by implementing steps of a moving method according to the invention. For the following description, the terminal D5 is called “localization terminal”.
Moreover, in the present embodiment, the localization terminal D5 has hardware architecture at least similar to that of the mapping terminal D2, so as to be able to implement the method for determining footprints. In other words, the localization terminal D5 is at least configured to receive, at a location of the area Z, one or several backscattered signals, decode said backscattered signal(s) and determine a footprint associated with said location.
As illustrated in
The read only memory D5_3 of the localization terminal D5 constitutes a recording medium in accordance with the invention, readable by the processor D5_1 and on which a computer program PROG_D5_1 in accordance with the invention is recorded, including instructions for the execution of steps of the moving method according to the invention. The program PROG_D5_1 defines functional modules of the localization terminal D5, which are based on or control the hardware elements D5_1 to D5_5 of the localization terminal D5 mentioned above, and which comprise in particular:
It should be noted that in the present exemplary embodiment, said first obtaining module MOD_OBT1_D5 is configured to operate similarly to the determination module MOD_DET_D2 equipping the mapping terminal D2.
The communication module D5_5 in particular allows the localization terminal D5 to communicate with the tracker D4, for example to exchange data via the wireless communication network. Said communication module D5_5 in particular integrates the second obtaining module MOD_OBT2_D5 and the third obtaining module MOD_OBT3_D5.
For the following description, it is considered without limitation that the sensory data respectively associated with the transmitter devices T present in the area Z are stored in a server (not representeed in the figures) external to the localization terminal D5. Consequently, the third obtaining module MOD_OBT3_D5 is more particularly configured to receive from said server the sensory data or data associated with said locating set E_REP, for example after having emitted an appropriate request to said server. It should however be noted that it remains possible to envisage, as mentioned previously, that the sensory data are stored in the storage means of one or several devices of the navigation system 10, such as for example in the non-volatile memory D5_4 of the localization terminal D5.
In the present embodiment, the localization terminal D5 includes a screen (it is the screen of the smartphone here), as well as display means configured to display on said screen one or several transmitter devices T of the area Z. Said display means are in particular configured to implement a man-machine interface making it possible to display on the screen one or several images respectively associated with the transmitter devices T. In this way, the user U2 can for example take note of images associated with transmitter devices belonging to a selection among all the transmitter devices T of the area Z.
In the context of the actual navigation phase, and according to the embodiment of
As illustrated in
Thus, the localization terminal D5 is in particular intended to move in the area (thanks to the user U2) so as to reach said intermediate location POS_INT that it is able to determine. Such movement is performed by using the sensory data associated with the locating set E_REP, as described in more detail later.
No limitation is attached to the nature of said information data INFO since it allows the user U2 to be informed that he has reached the intermediate location POS_INT. For example, said information data INFO is configured to generate an audible alarm played by sound means equipping the localization terminal D5 or to display an alert message on the screen of said localization terminal D5.
No limitation is attached to the value of the fraction considered for the neighborhood criterion CRIT_V either. For example, said fraction is at least equal to 50%.
It should be noted that in a more specific example of hardware architecture of the localization terminal D5, the first detection module MOD_DETEC1_D5 and the second detection module MOD_DETEC2_D5 can be integrated into the same general detection module (not represented in the figures).
The method for determining the intermediate path PATH_INT (executed by the tracker D4), the method for moving in the area Z (executed by the localization terminal D5) as well as the method for determining an intermediate location POS_INT (also executed by the localization terminal D5) are all three implemented during the execution of a general method, called “navigation method”. Said navigation method therefore groups together said methods for determining the intermediate path PATH_INT, for moving in the area Z and for determining an intermediate location POS_INT, and includes in particular the processing operations implemented by the navigation system 10 during said actual navigation phase.
For the following description, and for the purpose of simplifying it only, it is now considered without limitation that the sensory data are all images representing, in the environment of the area Z, objects to which the transmitter devices T are respectively affixed. It is further considered without limitation that each transmitter device T is associated with a single sensory data (image) DATA_IMA.
As illustrated by
The navigation method also includes a step F20 of receiving, by the localization terminal D5, one or several signals backscattered in said starting location POS_INI. Said step F20 belongs to the method for moving in the area Z and is implemented by the receiving module MOD_RX_D5 equipping the localization terminal D5.
It is recalled that the number of backscattered signals received by the localization terminal D5 of course depends on the number of transmitter devices T illuminated by the ambient signal emitted by the base station D1 and situated in the vicinity of said localization terminal D5.
The navigation method includes, following step F20 of receiving one or several backscattered signals, a step F30 of determining a current footprint EMP_CUR associated with the starting location POS_INI. Said step F30 is implemented by the localization terminal D5, in accordance with the footprint determination method able to be executed by said localization terminal D5 by means of the first detection module MOD_DETEC1_D5 and of the first obtaining module MOD_OBT1_D5 equipping it.
The navigation method then includes a step F40 of obtaining said current footprint EMP_CUR by the tracker D4. Said step F40 belongs to the method for determining the intermediate path PATH_INT and is implemented by the second obtaining module MOD_OBT2_D4 equipping the tracker D4. It is noted that this obtaining step of course follows a transmission of the current footprint EMP_CUR by the localization terminal D5 to the tracker D4.
The navigation method also includes a step F50 consisting in verifying whether said current footprint EMP_CUR forms or does not form a vertex of the graph G. Said step F50 belongs to the method for determining the intermediate path PATH_INT and is implemented by the test module MOD_TEST_D4 equipping the tracker D4.
For the following description of said mode of implementation, it is considered without limitation that the user U2 occupies a starting location POS_INI distinct from said locations POS_1, . . . . , POS_P respectively associated with the footprints EMP_1, . . . , EMP_P. More specifically, it is considered that the starting location POS_INI is sufficiently far from each of the locations POS_1, . . . . , POS_P for the current footprint EMP_CUR to be distinct from each of the footprints EMP_1, . . . , EMP_P. Consequently, the current footprint EMP_CUR does not form a vertex of the graph G.
The navigation method then includes a step F60 of updating the graph G so that the current footprint EMP_CUR forms a vertex of the updated graph G_NEW. Said step F60 belongs to the method for determining the intermediate path PATH_INT and is implemented by the update module MOD_UPD_D4 equipping the tracker D4.
The navigation method also includes a step F70 of determining a sequence SEQ of footprints of the updated graph G_NEW. Said sequence SEQ forms said intermediate path PATH_INT, so that said intermediate path PATH_INT is of minimum length to connect the starting location POS_INI to a footprint of the updated graph G_NEW identifying said transmitter device T_END. Said step F70 belongs to the method for determining the intermediate path PATH_INT and is implemented by the determination module MOD_DET_D4 equipping the tracker D4.
It should be noted that if it had been verified that the current footprint EMP_CUR already forms a vertex of the graph G, then the graph considered during the implementation of step F70 for the determination of the sequence SEQ would be the graph G itself, since no update would have taken place.
As illustrated in
The navigation method also includes a step F90 of obtaining the image(s) DATA_IMA making it possible to identify in a sensory manner, in the environment of the area Z, the transmitter device(s) T belonging to the locating set E_REP which is formed of the transmitter device(s) identified by said first footprint EMP_PATH_INT_1 and not identified by said current footprint EMP_CUR. Said step F90 belongs to the method for moving in the area Z and is implemented by the third obtaining module MOD_OBT3_D5 equipping the localization terminal D5.
In the present mode of implementation, said step F90 includes a sub-step of determining, by the localization terminal D5, said locating set E_REP. In this example, said determination sub-step is implemented by a dedicated module (not represented in the figures) equipping the localization terminal D5, this dedicated module possibly being for example a sub-module of the obtaining module MOD_OBT3_D5.
With regard to the representation in the form of a vector considered for a footprint, the determination of the locating set E_REP consists in performing a subtraction between the vectors respectively representative of the first footprint EMP_PATH_INT_1 and of the current footprint EMP_CUR.
As illustrated by
The navigation method also includes a step F110 of detecting, by the localization terminal D5, one or several transmitter devices, when it moves in accordance with step F100. Said step F110 belongs to the method for determining the intermediate location POS_INT and is implemented by the second detection module MOD_DETEC2_D5 equipping the localization terminal D5.
The navigation method also includes a step F120 of determining the intermediate location POS_INT satisfying the neighborhood criterion CRIT_V, when the localization terminal D5 moves by emitting the ambient signal in accordance with step F100. Said step F120 belongs to the method for determining the intermediate location POS_INT and is implemented by the determination module MOD_DET_D5 equipping the localization terminal D5.
It is noted that to determine the intermediate location POS_INT, the localization terminal D5 uses in particular the locating set E_REP it has already determined, in the present mode of implementation, following the execution of step F90.
Moreover, the navigation method includes a step F130 of generating an information data INFO able to indicate that the intermediate location POS_INT is reached. Said step F130 belongs to the method for determining the intermediate location POS_INT and is implemented by the generation module MOD_GEN_D5 equipping the localization terminal D5.
In accordance with the invention, steps F20 to F130 form a set of steps which is iterated as long as the first footprint EMP_PATH_INT_1 of the intermediate path PATH_INT does not identify said target transmitter device T_END (it is noted that step F10 does not need to be iterated insofar as it suffices that the graph G determined during the navigation preparation phase is obtained only once by the tracker D4).
Furthermore, for the implementation of the iterations of said set of steps F20 to F130, the starting location POS_INI considered in an iteration of said set of steps corresponds to the intermediate location POS_INT considered in the previous iteration. In other words, in the present mode of implementation, when the user U2 moves to reach an intermediate location POS_INT during an implementation of said set of steps F20 to F130, said intermediate location POS_INT becomes a starting location POS_INI for the next iteration of said set of steps F20 to F130.
Finally, still with regard to the implementation of said iterations, the graph considered in an iteration of said set of steps F20 to F130 for a possible update corresponds to the graph to which the intermediate path determined during the previous iteration belongs.
As mentioned above, once the user U2 has reached an intermediate location associated with a footprint identifying the target transmitter device T_END, said intermediate location constitutes an arrival location of the user U2. Consequently, the user U2 is able to reach the target transmitter device T_END, an image of which is accessible to him.
It should be noted that the navigation method has been described so far by considering that the localization terminal D5 determines the locating set E_REP from the first footprint EMP_PATH_INT_1 it has received. However, nothing excludes envisaging other modes of implementation in which the locating set E_REP is determined by a device other than the localization terminal D5 (this other device therefore receives the first footprint EMP_PATH_INT_1 and the current footprint EMP_CUR). Once the locating set E_REP has been determined by said other device, it is possible to envisage two alternative implementations:
For example, said other device is the tracker D4 (which is also in possession of the first footprint EMP_PATH_INT_1 and of the current footprint EMP_CUR) or a device distinct from the devices D1 to D5. Furthermore, in this example, the localization terminal D5 then includes an obtaining module MOD_OBT_D5 configured to obtain (receive) the locating set E_REP.
It is noted that in the case where the localization terminal D5 determines the locating set E_REP, it is of course also possible to envisage that it is equipped with an obtaining module MOD_OBT_D5 including, as sub-modules, the first obtaining module MOD_OBT1_D5 and the second obtaining module MOD_OBT2_D5 described above. The module MOD_OBT_D5 meeting such provisions is the one represented in
In general, no limitation is attached to the way in which the locating set E_REP is obtained by the localization terminal D5.
In a similar way to what was mentioned in the context of the navigation preparation method, it was implicitly assumed, for the implementation of the navigation method of
One particular exemplary implementation of the navigation method of
Said three
Sub-
As illustrated in sub-
Sub-
In the example of
The implementation of step F70 is performed as long as there is a vertex of the graph G_NEW that does not belong to the set E_V.
Thus, in the present case, step F70 begins with a determination (sub-step F70_1), among the vertices of the graph G_NEW that do not belong to the set E_V (therefore in this case all the vertices of the graph G_NEW given that E_V is initialized to the empty set), of a vertex of the graph G_NEW whose distance coefficient is minimal. Consequently, the vertex of the graph G_NEW thus determined is the current footprint EMP_CUR associated with the starting location POS_INI (the distance coefficients are initialized to infinity, except for C_DIST(EMP_CUR)).
The vertex thus determined is added (sub-step F70_2) to the set E_V. Consequently, the set E_V is no longer empty and contains the footprint EMP_CUR.
Subsequently, for each vertex EMP_i of the graph G_NEW that does not belong to the set E_V (i.e. for each distinct footprint of EMP_CUR in the present case), the following sub-steps are performed:
C_DIST(EMP_i)>C_DIST(EMP_CUR)+W(EMP_CUR,EMP_i);
The execution of said sub-steps F70_3, F70_4 and F70_5 for the vertices of the graph G_NEW that do not belong to the set E_V will be illustrated.
For this purpose, the vertex EMP_2 will be considered first. As illustrated by
The operations described above for EMP_2 provide the same results for the vertex EMP_4. Indeed, said vertex EMP_4 is connected by a single edge to the vertex EMP_CUR, as illustrated by
On the other hand, all the vertices of the graph G_NEW other than EMP_CUR, EMP_2 and EMP_4 do not have their respective distance coefficients modified since they do not verify the inequation: C_DIST(EMP_i)>C_DIST(EMP_CUR)+W(EMP_CUR, EMP_i). Furthermore, these vertices of the graph G_NEW other than EMP_CUR, EMP_2 and EMP_4 are not assigned any predecessors.
Once said sub-step F70_3 (and possibly said sub-steps F70_4 and F70_5) has been executed for each vertex EMP_i of the graph G_NEW that does not belong to the set E_V, said sub-steps F70_1 to F70_3 (and optionally said sub-steps F70_4 and F70_5) are iterated.
The first iteration of said sub-steps F70_1 to F70_3 (and possibly said sub-steps F70_4 and F70_5) will be illustrated by way of example. For the first iteration of step F70_1, the set E_V now includes the vertex EMP_CUR. Two vertices of the graph G_NEW provide a minimum distance coefficient among the vertices of the graph G_NEW that do not belong to the set E_V: EMP_2 and EMP_4. Indeed, it follows from the previous implementation of sub-steps F70_1 to F70_5 that C_DIST(EMP_2)=C_DIST(EMP_4)=1 (on the other hand, we always have C_DIST(EMP_i) which is infinite for EMP_i different from EMP_2 and EMP_4).
A choice is therefore made between EMP_2 and EMP_4 to designate the vertex that will be added to the set E_V during the first iteration of sub-step F70_2. It is considered, without limitation, that the vertex EMP_2 is chosen and therefore added to E_V which now contains EMP_CUR and EMP_2 (it is noted that this choice is arbitrary, the vertex EMP_4 can just as well be chosen).
Therefore said sub-step F70_3 (and possibly said sub-steps F70_4 and F70_5) is iterated for each of the vertices that do not belong to the set E_V. The case of the vertex EMP_4 that does not belong to the set E_V will be considered first. Then, insofar as a single edge connects the vertices EMP_2 and EMP_4 (as illustrated by
The case of the vertex EMP_5 that does not belong to the set E_V will now be considered. We have that C_DIST(EMP_5) is infinite because initialized as such and still never modified. Moreover, we also have that W(EMP_2, EMP_5) is equal to 1 because a single edge connects the vertices EMP_2 and EMP_5. Consequently, we have: C_DIST(EMP_5)>C_DIST(EMP_2)+W(EMP_2, EMP_5), so that said sub-steps F70_4 and F70_5 are iterated. More specifically, the distance coefficient C_DIST(EMP_5) is modified to take the value C_DIST(EMP_2)+W(EMP_2, EMP_5)=1+1=2. Furthermore, the vertex EMP_2 is designated as being the predecessor of the vertex EMP_5.
The iteration of said sub-step F70_3 (and possibly of said sub-steps F70_4 and F70_5) is performed for each of the other vertices that do not belong to the set E_V.
Once this is completed, sub-steps F70_1 to F70_3 (and possibly said sub-steps F70_4 and F70_5) are iterated again, etc. The iteration process continues as long as there is a vertex of the graph G_NEW that does not belong to the set E_V.
Once all the iterations have been completed, step F70 includes a selection (sub-step F70_6), among the footprint(s) of the set L_DEST, of the footprint whose distance coefficient is minimal. In the present examplary implementation, only one footprint belongs to L_DEST, namely EMP_10. It is therefore said footprint EMP_10 that is selected.
The sequence SEQ, which forms the intermediate path PATH_INT, is then determined (sub-step F70_7) so that:
It is therefore understood that the sequence SEQ is built backwards, by taking into account the different predecessors determined during the different iterations.
Ultimately, in the example of
The user U2 therefore moves in the area Z by using the sensory data displayed on the screen of localization terminal D5. Said sensory data are those of said locating set E_REP and which are associated with the transmitter devices identified by the footprint EMP_2 and not identified by the footprint EMP_CUR. During its movement, the localization terminal D5 receives backscattered signals and detects the transmitter devices T that are illuminated by the ambient signal and that belong to the locating set E_REP. When the number of transmitter devices T detected is at least equal to the fraction considered for the neighborhood criterion CRIT_V to be satisfied, this means that an intermediate location POS_INT has been determined by the localization terminal D5. Therefore, in the present exemplary embodiment, an information data INFO is emitted by the localization terminal D5 in the form of a sound (audible alert) to warn the user U2 that he has reached said intermediate location POS_INT. Following that, steps F20 to F130 can be reiterated.
Ultimately, in the example of
The invention has been described so far by considering that a single receiver device D2 (mapping terminal in the embodiments considered above) can receive backscattered signals during the navigation preparation phase. However, nothing excludes envisaging embodiments in which the navigation system 10 includes, for said navigation preparation phase, a plurality of receiver devices similar to the receiver device D2. More particularly, in these other embodiments, each receiver device belonging to said plurality of receiver devices is associated with one or several locations among said locations POS_1, . . . . , POS_P. Moreover, the locations associated with a receiver device are distinct from those associated with another receiver device. In other words, in these other embodiments, said locations POS_1, . . . . , POS_P are distributed among several receiver devices similar to the receiver device D2. Thus, it is for example possible to envisage having a number of receiver devices equal to P, each of said P receiver devices being associated with a location among said locations POS_1, . . . . , POS_P.
The invention has moreover been described so far considering that all the devices belonging to the navigation system 10 are distinct from each other. However, the invention is not limited by such provisions, and it is possible to envisage that:
Nothing excludes envisaging that the emitter device D1, the base station D1 in the embodiment of
It has further been considered so far that it is the receiver device D2 that implements the step of determining the footprint EMP_i during the navigation preparation phase (step E40[i] of the navigation preparation method). Of course, it is also possible to envisage that the determination of the footprint EMP_i is implemented by a device other than said receiver device D2 (and furthermore other than one of said devices D1, D3, D4, and D5), this other device obtaining from the receiver device D2 information relating to the transmitter devices T detected by said receiver device D2.
According to a similar principle, it is possible to envisage that a device other than the receiver device D5 implements the step of determining the current footprint EMP_CUR (step F30 of the navigation method), this other device obtaining from the receiver device D5 information relating to the transmitter devices T detected by said receiver device D5.
It is important to note that the invention can also be implemented by envisaging a neighborhood criterion CRIT_V which differs from the one described so far, so that it is not necessary to determine an intermediate location as described previously. Indeed, and according to other embodiments, the neighborhood criterion can be defined so as to be satisfied if the receiver device D5 (localization terminal D5 in the embodiments considered above) reaches, during its movement (step F100 of the navigation method), a location at which is situated:
Finally, the invention has also been described so far by considering that a device intended to move in the area Z (receiver device D2 and/or receiver device D5) is held by a user, so that a movement of said device corresponds to a movement of said user. That said, the invention remains applicable in the case where a device intended to move in the area Z (receiver device D1 and/or receiver device D5) is not held by any user and is able to move autonomously.
To this end, and according to one exemplary embodiment, such a device corresponds to a mechatronic device (for example a robot) including drive means (such as for example an electric or thermal motor, etc.) as well as movement means (such as wheels, tracks, etc.). Such a mechatronic device further includes identification means configured to identify, in the environment of the area Z, one or several transmitter devices T from their respective sensory data. For example, said identification means can correspond to visual identification means (recognition of shapes/images) and include:
Of course, nothing excludes considering, according to other exemplary embodiments not detailed here, a device configured in a suitable manner to move autonomously from sensory data other than images (sounds, videos, etc).
| Number | Date | Country | Kind |
|---|---|---|---|
| FR2011303 | Nov 2020 | FR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/FR2021/051895 | 10/27/2021 | WO |
