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

A non-transitory computer readable storage medium comprising computer executable instructions that when executed by a computer will cause the computer to carry out a method of estimating a location of a target device in a region of space, the method comprising:

• obtaining a first set of detected signals by detecting, at one or more detectors, a beacon signal from the target device, or by detecting at the target device, beacon signals sent from one or more radio transmitters;
• determining, based on characteristics of the first set of detected signals, a current estimate of the location of the target device;
• obtaining a second set of detected signals by detecting, at the one or more detectors, a beacon signal from the target device, or by detecting at the target device, a beacon signal sent from the one or more radio transmitters;
• for the second set of detected signals:
• determining, based on characteristics of the second set of detected signals and the current estimate of the location of the target device, one or more candidate locations for the target device at which the target device is likely located at the present point in time;
• comparing the one or more candidate locations for the target device with a radio map of the region of space, the radio map identifying obstructions to radio wave propagation in the region of space to select one or more feasible candidate locations for the target device;
• and
• determining a new estimate of the location of the target device based on the one or more feasible candidate locations for the target device.

A location method of estimating a location of a target device in a region of space, the method comprising:

• obtaining a first set of detected signals by detecting, at one or more detectors, a beacon signal from the target device, or by detecting at the target device, beacon signals sent from one or more radio transmitters;
• determining, based on characteristics of the first set of detected signals, a current estimate of the location of the target device;
• and
• for each of one or more iterations:
• predicting, based at least in part on the current estimate of the location of the target device, 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 one or more candidate locations for the target device with a radio map of the region of space, the radio map identifying obstructions to radio wave propagation in the region of space to select one or more feasible candidate locations for the target device;
• determining, based on the feasible candidate locations, a sub-region of space in which the target device is predicted to be located for the target device;
• obtaining a second 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, a beacon signal sent from one or more radio transmitters in the sub-region of space;
• and
• determining, based on characteristics of the second set of detected signals and the one or more feasible locations, a new estimate of the location of the target device.