Performing localisation of a first user device

A localisation determiner for performing localisation of a first user device comprising an environment sensor, the localisation determiner comprising:

• a processor;
• and
• a memory storing instructions that, when executed by the processor, cause the localisation determiner to:
• determine a dynamicity parameter indicating an extent of environment dynamicity of the environment of the first user device based on motion properties of one or more mobile user devices located in the vicinity of the first user device, wherein the motion properties have been gathered over a period of time, and wherein the one or more mobile user devices are associated with different persons than the person with whom the first user device is associated;
• determine whether the dynamicity parameter indicates that the first user device is in a dynamic environment;
• as a result of determining that the dynamicity parameter indicates that the first user device is in a dynamic environment, trigger localisation to occur using localisation procedures of a cellular network to which the first user device is connected;
• or
• as a result of determining that the dynamicity parameter indicates that the first user device is not in a dynamic environment, trigger localisation to occur using at least one environment sensor of the first user device.

A non-transitory computer readable medium storing a computer program for performing localisation of a first user device comprising an environment sensor, the computer program comprising computer program code which, when run on a localisation determiner causes the localisation determiner to:

• determine a dynamicity parameter indicating an extent of environment dynamicity of the environment of the first user device based on motion properties of one or more mobile user devices, located in the vicinity of the first user device, wherein the motion properties have been gathered over a period of time, and wherein the one or more mobile user devices are associated with different persons than the person with whom the first user device is associated;
• determine whether the dynamicity parameter indicates that the first user device is in a dynamic environment;
• as a result of determining that the dynamicity parameter indicates that the first user device is in a dynamic environment, trigger localisation to occur using localisation procedures of a cellular network to which the first user device is connected;
• or
• as a result of determining that the dynamicity parameter indicates that the first user device is not in a dynamic environment, trigger localisation to occur using at least one environment sensor of the first user device.