Radio-location method for locating a target device contained within a region of space

6:

• A method according to claim 4, wherein the step of determining one or more candidate locations for the target device comprises:
• determining, based on characteristics of the set of detected signals, a preliminary set of one or more candidate locations;
• and
• discarding, from the preliminary set of one or more candidate locations, one or more candidate locations that are not consistent with the current estimate of the target device's location;
• wherein the step of comparing the candidate locations with a radio map of the region of space is carried out using the preliminary set of one or more candidate locations, with the candidate location(s) that are not consistent with the current estimate of the target device's location having been discarded.

9:

• A radio-location method of locating a target device that is contained within a region of space, the method comprising:
• obtaining a first set of detected signals by detecting, by one or more detectors at a plurality of points in space, a beacon signal from the target device, or by detecting at the target device, beacon signals sent from one or more radio transmitters in the region of space;
• determining, based on characteristics of the first set of detected signals, a current estimate of the target device's location;
• and
• for each of one or more iterations:
• predicting, based at least in part on the current estimate of the target device's location, one or more new candidate locations for the target device at which the target device is likely located at the present point in time;
• comparing the candidate locations with a radio map of the region of space, the radio map identifying obstructions to radio wave propagation contained within the region of space;
• identifying, from the one or more candidate locations, one or more feasible candidate locations that are consistent with the radio map;
• determining, based on the feasible candidate locations, a sub-region of space in which the target device is predicted to be located;
• obtaining a further set of detected signals by detecting, at one or more detectors in the sub-region of space, a beacon signal sent from the target device, or by detecting at the target device, beacon signals sent from one or more radio transmitters in the sub-region of space;
• determining, based on characteristics of the further set of detected signals and the one or more feasible locations, a new estimate of the target device's location;
• and
• setting the new estimate as the current estimate of the target device's location.