Apple Granted Patent for Dynamic Compass Calibration

Apple has received a Granted Patent relating to techniques for calibrating an electronic compass that is integrated into an iDevice like the iPhone.

One of the drawbacks of current electronic compass technology, integrated in a portable device such as a smartphone or cellular phone, is that due to being subjected to widespread and variable magnetic interference sources, the compass direction output is in error quite often. This characteristic of the integrated compass may be ameliorated, by using an improved technique that indicates when the environment in which the portable device and/or the magnetic sensor find themselves has changed, such that the calibration process needs to be restarted.

In accordance with an embodiment of the invention, a machine-implemented method for dynamic calibration of a compass in a portable device operates as follows. A magnetic field surrounding the device is monitored during a given time interval, as the portable and its compass function are being used in the normal course by the end user. For example, the magnitude of the magnetic field and the geomagnetic inclination or dip of the geomagnetic field may be monitored during the same time interval. When certain criteria relating to the monitored magnetic field magnitude and geomagnetic inclination angle are met, then this indicates that a new environment has been entered or created around the portable device or the magnetic sensor, such that immediate recalibration is needed.

In another embodiment, in addition to the magnetic field, one or more of position, orientation and movement (POM) of the portable is also monitored during the same interval. Changes in the monitored magnetic field are compared with changes in the monitored POM, to determine when the portable device or magnetic sensor finds itself in a different environment at which time recalibration of the compass is signaled. For example, whenever the change in the monitored magnetic field is large relative to the change in the monitored POM, recalibration of the compass is signaled. As a further example, when the percentage change in the magnetic field is larger than the percentage change in the POM, then recalibration is signaled. This might occur where, for example, the user has been walking for several minutes while carrying the portable and has now gotten into his car; the presence of the car has significantly altered the compass' interference field, but the change in the location of the portable on Earth is by contrast small (in terms of experiencing a change in the geomagnetic field). Other user contexts that can cause an expected change in the monitored magnetic field relative to an expected change in the monitored POM, signifying a change in the environment calling for recalibration, are possible.

Apple credits Patrick Piemonte, Madhu Shrivastav, Puneet Mishra, Robert Mayor, Ronald Huang and Parin as the inventors of granted patent 8,239,153 which was originally filed in Q and published today by the US Patent and Trademark Office.

Apple has also been granted their second patent on controlling your desktop from your iPhone. Their first granted patent was covered in 2009. And finally, Apple has been granted a patent for adjusting camera setting on a touch screen iDevice.

Final Patent Round-Up

Over and above the granted patents that were specifically reported on today, we present you with links to all of the other granted patents in our Final Patent Round-Up as follows:

8,238,977 Antenna systems with common overhead for CDMA base stations

8,238,971 Accessory detection to minimize interference with wireless communication

8,238,956 Adjusting power of a control channel based on a characteristic of a message in the control channel

8,238,893 Techniques for controlling a portable media device having a radio frequency tuner

8,238,831 Wireless interference mitigation

8,238,811 Cross-transport authentication

8,238,608 Tracking workflow in manipulating media items

8,238,482 Techniques for improving channel estimation and tracking in a wireless communication system

8,238,460 Method and system for retransmitting data packets

8,238,157 Selective re-programming of analog memory cells

8,238,087 Display module

8,237,723 Deferred deletion and cleanup for graphics resources

8,237,712 Manipulation of image content using various image representations

8,237,667 Phase compensation for multi-stimulus controller

8,237,506 Doherty amplifier and method for operation thereof

Notice

Patently Apple presents only a brief summary of granted patents with associated graphics for journalistic news purposes as each Granted Patent is revealed by the U.S. Patent & Trademark Office. Readers are cautioned that the full text of any Granted Patent should be read in its entirety for full details. About Comments: Patently Apple reserves the right to post, dismiss or edit comments.