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US 11,686,584 B2Granted
3D long-range through-the-wall magnetoquasistatic coupling and application to indoor position sensing
AssigneeCalifornia Institute of Technology
InventorDarmindra D. Arumugam
Life of this patent
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Abstract
Methods and systems for indoor position sensing are disclosed. The described methods and systems are based on magnetoquasistatic field coupling theory and can be implemented in two- and three-dimensional, long-range, through-the-wall applications, where the transmitting devices are implemented outdoor, the receiving device is implemented indoor, or vice versa. Measurement systems implemented to characterize the disclosed methods are also presented for both two- and three-dimensional applications involving indoor position sensing. Orientation sensing methods and systems are also disclosed.
Claims26
A long-range, through-the-wall position sensing method comprising:
- providing one or more transmitting devices, each configured to transmit quasistatic magnetic fields along one or more transmitting axes;
- providing at least one receiving device configured to receive quasistatic magnetic fields along one or more receiving axes;
- placing the one or more transmitting devices outside an enclosed space having an outer wall;
- placing the at least one receiving device inside the enclosed space;
- transmitting through the outer wall, by the one or more transmitting devices, the quasistatic magnetic fields in one or more frequency bands;
- detecting, by the at least one receiving device, one or more quasistatic magnetic field couplings between each axis of each of the one or more transmitting axes and each axis of the one or more receiving axes;
- based on the detected quasistatic magnetic fields, calculating orientation-invariant ranges between the at least one receiving device and each of the one or more transmitting devices, the calculating comprising contributions from complex images of the one or more transmitting devices, thereby accounting for induced eddy-currents in ground due to transmitted quasistatic magnetic fields, and wherein the contributions from complex images are based on a dependency of the detected quasistatic magnetic fields on an inverse of distances of the complex images from the at least one receiving device to a third power.
4 more elements
A two-dimensional system comprising at least two transmitting devices placed outside an enclosed space and at least one receiving device placed inside the enclosed space, the system configured to operate according to a method comprising:
- providing one or more transmitting devices, each configured to transmit quasistatic magnetic fields along one or more transmitting axes;
- providing at least one receiving device configured to receive quasistatic magnetic fields along one or more receiving axes;
- placing the one or more transmitting devices outside an enclosed space having an outer wall;
- placing the at least one receiving device inside the enclosed space;
- transmitting through the outer wall, by the one or more transmitting devices, the quasistatic magnetic fields in one or more frequency bands;
- detecting, by the at least one receiving device, one or more quasistatic magnetic field couplings between each axis of each of the one or more transmitting axes and each axis of the one or more receiving axes, and
- based on the detected quasistatic magnetic fields, calculating orientation-invariant ranges between the at least one receiving device and each of the one or more transmitting devices, the calculating comprising contributions from complex images of the one or more transmitting devices, thereby accounting for induced eddy-currents in ground due to transmitted quasistatic magnetic fields,
- wherein:
- the at least two transmitting devices and the at least one receiving device are all at substantially same heights from ground, and
- the calculating the ground truth position of the at least one receiving device comprises trilateration.
7 more elements
A long-range, through-the-wall position and orientation sensing method comprising:
- providing a transmitting device configured to transmit quasistatic magnetic fields along one or more transmitting axes;
- providing one or more receiving devices configured to receive quasistatic magnetic fields along one or more receiving axes of each of the one or more receiving devices;
- placing the transmitting device outside an enclosed space having an outer wall;
- placing the one or more receiving devices inside the enclosed space;
- transmitting through the outer wall, by the transmitting device, the quasistatic magnetic fields in one or more frequency bands;
- detecting, by each of the one or more receiving devices, one or more quasistatic magnetic field couplings between each axis of each of the transmitting device and each axis of the one or more receiving axes of the one or more receiving devices, and
- based on the detected quasistatic magnetic fields, calculating:
- ranges between the transmitting device and each of the one or more receiving devices;
- angular directions to each of the one or more receiving devices;
- orientation of each of the one or more receiving devices, and
- contributions from a complex image of the transmitting device, thereby accounting for induced eddy-currents in ground due to transmitted quasistatic magnetic fields, and wherein the contributions from complex images are based on a dependency of the detected quasistatic magnetic fields on an inverse of distances of the complex images from the at least one receiving device to a third power.
8 more elements
Dependencies are inferred from the claim text.