Abstract: Responsive to a recalibration trigger event, magnetometer data output by a magnetometer can be compared to historical magnetometer data previously output by the magnetometer. If a match is determined, a confidence of the match can be determined using theoretically constant data related to Earth's magnetic field. The constant data can be calculated from the historical magnetometer data. If the confidence of the match exceeds a confidence threshold level, historical calibration data can be used to calibrate the magnetometer. If the confidence of the match does not exceed the confidence threshold level, a calibration procedure can be performed to generate new calibration data, and the new calibration data can be used to calibrate the magnetometer.

Abstract: A parameter related to the Earth's magnetic field can be used to determine accuracy of a magnetometer of a mobile device. In one aspect, a first instance of a parameter related to Earth's magnetic field is determined using data generated by the magnetometer. The magnetometer data can be based in part on a position of the mobile device with respect to the Earth. A second instance of the parameter can be determined using data generated by a model of Earth's magnetic field. The model data can also be based in part on the position of the mobile device with respect to the Earth. The first instance of the parameter can be compared with the second instance of the parameter. An accuracy metric for the magnetometer can be determined based on a result of the comparison. An indication of the accuracy metric can be presented by the mobile device.

Abstract: Customizing a device based on space and time (e.g., a geographic position of the device at a particular time) is disclosed. In one aspect, geographic position data of a device is obtained. Temporal data that is related to the geographic position data is obtained. An operational mode is selected based on the geographic position data and the temporal data for activation on the device. In some implementations, the operational mode identifies a communication medium.

Abstract: An interactive game environment includes two or more co-located, networked, direction and location aware interactive game devices. The game devices share a common reference coordinate frame (e.g., a three-dimensional Cartesian coordinate frame). Each game device maintains its own device state (e.g., position, orientation, time) in the reference coordinate frame. Each interactive game device shares its device state with the other interactive game devices using communication technology (e.g., Bluetooth, Wi-Fi, cellular). Each interactive game device can use the device states of the other interactive game devices to project the relative positions and orientations of the other interactive game devices into a local, fixed coordinate frame of the interactive game device. These projections allow each interactive gaming device to know the position and orientation of the other interactive game devices in an interactive game environment defined by the reference coordinate frame.