Abstract: A computer-implemented method 1000 of constructing a model of the motion of a mobile device, wherein the method comprises using a sensor of the device to obtain 1002 positional data providing an estimated pose of the mobile device, generating an initial graph 1004 based upon the positional data from the sensor, nodes of which graph provide a series of possible poses of the device, and edges of which graph represent odometry and/or loop closure constraints; processing the graph to estimate 1006 confidence scores for each loop closure by performing pairwise consistency tests between each loop closure and a set of other loop closures; and generating an augmented graph from the initial graph by retaining or deleting 1008 each loop closure based upon the confidence scores.

Abstract: A computer-implemented method 1000 of constructing a model of the motion of a mobile device, wherein the method comprises using a sensor of the device to obtain 1002 positional data providing an estimated pose of the mobile device, generating an initial graph 1004 based upon the positional data from the sensor, nodes of which graph provide a series of possible poses of the device, and edges of which graph represent odometry and/or loop closure constraints; processing the graph to estimate 1006 confidence scores for each loop closure by performing pairwise consistency tests between each loop closure and a set of other loop closures; and generating an augmented graph from the initial graph by retaining or deleting 1008 each loop closure based upon the confidence scores.

Abstract: A method of determining the position of a mobile device uses a model. The model is constructed by obtaining a map of a geographical area, constructing the graph using the map, wherein vertices of the graph correspond to areas of the map, and two vertices are joined by an edge when the areas corresponding to the vertices are adjacent and can be travelled between by a device, and building the one or more feature functions using the graph, wherein a feature value of the one or more feature functions indicates the extent to which the observations support the device being positioned in the areas corresponding to one or more vertices of the graph.

Abstract: A method of determining the position of a mobile device using a model. The model comprises a graph comprising a set of vertices and a set of edges between the vertices, and one or more feature functions that take as input one or more vertices of the graph and a set of observations for the device, and return a feature value. The model is constructed by obtaining a map of the geographical area, constructing the graph using the map, wherein the vertices of the graph correspond to areas of the map, and two vertices are joined by an edge when the areas corresponding to the vertices are adjacent and can be travelled between by a device, and building the one or more feature functions using the graph, wherein the feature value of the one or more feature functions indicates the extent to which the observations support the device being positioned in the areas corresponding to the one or more vertices of the graph.

Abstract: A system for providing locality information to a user is disclosed. The system comprises at least one magnetic field beacon. Each beacon comprises means for generating a magnetic field encoded with information associated with the beacon. A communication device is provided that comprises means for detecting the encoded magnetic field emitted by the beacon and means for extracting the information encoded in the detected magnetic field.

Abstract: A system for providing locality information to a user is disclosed. The system comprises at least one magnetic field beacon. Each beacon comprises means for generating a magnetic field encoded with information associated with the beacon. A communication device is provided that comprises means for detecting the encoded magnetic field emitted by the beacon and means for extracting the information encoded in the detected magnetic field.