Mobile Device Motion State Identification Using Consecutive Step Detection
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Solution Overview
Problem
Conventional MEMS accelerometer-based motion state identification systems fail to distinguish between low average velocity motion states, such as fidgeting, and high average velocity motion states, leading to inaccurate movement detection in mobile devices.
Innovation Solution
A method and apparatus that utilize a step detector and processor to analyze acceleration signals from one or more accelerometers, detecting pedestrian steps and determining the maximum number of consecutive steps to differentiate between high average velocity purposeful motion and low average velocity fidgeting states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional MEMS accelerometer-based stationarity detection is used, then movement detection is provided independently from environmental RF signals, but the system incorrectly indicates movement during low average velocity fidgeting states
Solution Approach 1:
The patent changes the parameter used for motion detection from simple acceleration magnitude to the rate of change of acceleration (jerk). By detecting transitions when the rate of change exceeds a threshold, the system can distinguish between fidgeting (low average velocity with frequent small movements) and purposeful motion (high average velocity with sustained acceleration patterns), thereby improving measurement precision while maintaining reliability
Solution Approach 2:
The system dynamically adjusts the threshold for detecting motion based on the observed acceleration patterns. Rather than using a fixed threshold, the system adapts to the current motion context, allowing it to differentiate between stationary, fidgeting, and purposeful motion states more accurately, thus resolving the contradiction between reliability and precision
2Productivity
If the system detects any acceleration change as movement, then it provides comprehensive movement detection, but it cannot distinguish between fidgeting and sustained pedestrian motion
Solution Approach 1:
The patent segments the motion detection space into distinct categories: stationary state, fidgeting state, and purposeful motion state. By analyzing the rate of change of acceleration and comparing it against thresholds, the system segments different motion patterns and classifies them appropriately, maintaining comprehensive detection coverage while achieving precise motion state classification
Solution Approach 2:
The system employs periodic sampling of acceleration data and analyzes transitions over time intervals. By examining the temporal pattern of acceleration changes and the duration of detected transitions, the system can distinguish between brief fidgeting movements and sustained purposeful motion, thereby maintaining high productivity while improving classification precision
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Accurately identifies motion states, enabling efficient movement information provision, optimizing cellular telephony and context-aware computing by distinguishing between fidgeting and sustained pedestrian motion.
Implementation Method 1
The apparatus may use acceleration signals from one or more accelerometers
Data Source
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AI summary
Systems and methods for identifying a motion state of a mobile device are disclosed. In one embodiment, identifying a motion state of a mobile device using acceleration signals from one or more accelerometers comprises: detecting any pedestrial steps associated with a user of the mobile device during an observation period based on the acceleration signals; determining a maximum number of consecutive pedestrial steps taken during the observation period from the detected pedestrial steps; and declaring a high average velocity motion state or a low average velocity motion state for the observation period based on the determined maximum number of consecutive pedestrial steps.