Method for determining a graph modelling a geographical zone, system for navigating within the zone using said graph

A device for determining a graph modeling a geographical area, said geographical area including at least one transmitter device configured to backscatter towards a receiver device an ambient signal emitted by an emitter device for detection by said receiver device, said determination device including:

• an obtaining module configured to obtain at least one footprint of said geographical area, said at least one footprint having been determined for a location of said geographical area and corresponding to a data identifying, among said at least one transmitter device, any transmitter devices detected by the receiver device when the emitter device emits the ambient signal from the location associated with said footprint, wherein said footprint comprises a set of identifiers determined based on a presence or absence of the detected transmitter devices in said geographical area, and
• a determination module configured to determine a graph having at least one vertex, each vertex of said graph formed of a respective footprint of said at least one footprint, two vertices of said graph being connected by an edge if the footprints relating to said two vertices include at least one transmitter device detected in common.

A device for ambient backscatter communication in a geographical area, said area including at least one transmitter device configured to backscatter towards a receiver device a pre-existing ambient signal emitted by said emitter device, distinct from the receiver device, so as to be detected by said receiver device, said emitter device including an emission module configured to emit said ambient signal when, following a movement of said emitter device to reach at least one location of said geographical area, said at least one location has been reached,

• wherein the emitted ambient signal enables determination of a footprint corresponding to a data identifying, among said at least one transmitter device, transmitter devices detected by the receiver device from said at least one location, the footprint comprising a set of identifiers determined based on a presence or absence of the detected transmitter devices, and
• wherein the footprints form vertices of a graph in which two vertices are connected if corresponding footprints include at least one transmitter device detected in common.