Abstract: Methods and apparatuses for estimating a user's altitude with respect to the mean sea level are provided. According to some aspects, the present invention is able to estimate altitude in both open sky as well as in degraded GPS signal environments such as dense urban canyon environments where GPS performance is affected by fewer available satellites and/or multipath error. According to other aspects, the present invention uses data from a pressure sensor to estimate altitude, either with or without the use of GPS aiding data. According to further aspects, estimated altitude is integrated with other types of dead reckoning data to provide user context detection pertaining to changes of altitude.

Abstract: A method and apparatus of detecting and using motion modes in a mobile device is described. Movement data is collected from an inertial motion unit (IMU) of the mobile device and compared to two or more sets of training data, each set of training data corresponding to a different motion mode. Then, a motion mode is determined to be the current mode of the mobile device on the results of the comparison. The motion mode is used by the mobile device in a variety of applications.