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US 10,209,075 B2Granted
Orientation determination for devices generating electromagnetic interference
AssigneeNXP USA, Inc.
InventorMichael E. Stanley
Life of this patent
Estimating the term…
Abstract
A mechanism is provided to determine orientation of a device that includes sources of electromagnetic interference. Data generated by one or more gyroscopes in the device, in conjunction with data generated by one or more accelerometers, can be used to generate an estimate of the change of orientation of the device from the time of a last accurate magnetometer reading. In one embodiment, in order to conserve system power, the gyroscope is kept powered down or in a stand-by state until receiving a control signal to power up. The control signal is provided in advance of the source of electromagnetic interference being powered up, thereby providing an accurate starting point from which magnetometer orientation estimates may be calculated during such interference.
Claims20
A system comprising:
- a component capable of generating electromagnetic interference;
- a first set of directionally-sensitive sensors, wherein
- the first set of directionally-sensitive sensors comprises three orthogonally-oriented sensors configured to respond to a magnetic field, and
- the first set of directionally-sensitive sensors are mounted within range of the electromagnetic interference wherein generation of the electromagnetic interference causes the first set of directionally-sensitive sensors to generate erroneous data related to the magnetic field;
- a second set of directionally-sensitive sensors, wherein
- the second set of directionally-sensitive sensors comprises three orthogonally-oriented sensors configured to respond to a constant acceleration, and
- the second set of directionally-sensitive sensors are mounted in a fixed orientation to the first set of directionally-sensitive sensors;
- a set of gyroscope sensors, wherein
- the set of gyroscope sensors comprises three sensors oriented on orthogonally-oriented axes each configured to respond to rotation about a corresponding axis, and
- the set of gyroscope sensors are mounted in a fixed orientation to the first and second sets of directionally-sensitive sensors;
- a processor, coupled to the first and second set of directionally sensitive sensors and the set of gyroscope sensors, and configured to
- determine a first orientation of the system with respect to a global frame of reference using first signals received from the first and second sets of directionally-sensitive sensors at a first time, and
- determine a second orientation of the system with respect to the global frame of reference at a second time, using second signals received from the first and second sets of directionally-sensitive sensors, and correlating an observed angular rate of change of the system from first gyroscope signals from the set of gyroscope sensors during a period between the first time and the second time to the rotational change reflected by the first and second signals received from the directionally-sensitive sensors;
- determine a third orientation of the system with respect to the global frame of reference using the second orientation, and one or more of third signals received from the first and second sets of directionally-sensitive sensors at a third time and an observed angular rate of change of the system using second gyroscope signals from the set of gyroscope sensors during a period between the second time and the third time, wherein said determining the second and third orientation is performed in response to receiving a control signal.
11 more elements
A method implemented by a digital still camera, the method comprising:
- determining a first orientation of the digital still camera with respect to a global frame of reference at a first time using first data generated by a first set of directionally-sensitive sensors and a second set of directionally-sensitive sensors, wherein
- the first set of directionally-sensitive sensors comprises three orthogonally-oriented sensors configured to respond to a constant magnetic field,
- the first set of directionally-sensitive sensors are mounted on or near a lens comprising a motor capable of generating electromagnetic interference sufficient to cause the first set of directionally-sensitive sensors to generate erroneous data related to the constant magnetic field, and
- the second set of directionally-sensitive sensors comprises three orthogonally-oriented sensors configured to respond to a constant acceleration and are mounted in a fixed orientation to the first set of directionally-sensitive sensors;
- determining a second orientation of the digital still camera with respect to the global frame of reference at a second time using the first orientation and second data generated by the first and second sets of directionally-sensitive sensors at the second time;
- correlating a first observed angular rate of change of the digital still camera generated by a set of gyroscope sensors during a period between the first time and the second time to the rotational change reflected by the first and second orientation, wherein
- the set of gyroscope sensors comprises three sensors on orthogonally-oriented axes configured to respond to rotation about a corresponding axis,
- the set of gyroscope sensors are mounted in a fixed orientation to the first and second sets of directionally-sensitive sensors and
- said correlating is performed in response to a control signal;
- and
- determining a third orientation of the digital still camera with respect to the global frame of reference at a third time using the second orientation, and one or more of data generated by the first and second sets of directionally sensitive sensors at the third time and a second observed angular rate of change of the digital still camera generated by the set of gyroscope sensors during a period between the second time and the third time.
8 more elements
Dependencies are inferred from the claim text.