Step Length Estimation Using Acceleration Variance for Walking and Running States
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Solution Overview
Problem
Existing step length estimation methods in portable terminals inaccurately measure movement distance due to integrating walking and running states without discrimination, resulting in reduced efficiency to approximately 84-83 percent, as the patterns of walking frequency and acceleration variance differ significantly between these states.
Innovation Solution
A portable terminal equipped with an accelerometer that determines the movement state based on acceleration variance values, using different step estimation algorithms for walking and running states to accurately calculate step length by employing distinct step length estimation parameter coefficients for each state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If walking and running states are integrated and modeled together, then the device complexity is reduced, but the measurement precision deteriorates to approximately 84-83 percent
Solution Approach 1:
The patent segments the movement analysis into two distinct states: walking state and running state. By separating the modeling process into state-specific models rather than using a single integrated model, the system achieves more accurate step length estimation for each state while maintaining manageable complexity through state-based classification.
2Measurement precision
If different step length estimation parameter coefficients are used for walking and running states, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The patent implements dynamic adaptation of estimation parameters based on detected movement state. The system automatically switches between walking-state coefficients and running-state coefficients according to the current movement state, enabling the algorithm to adapt its parameters dynamically rather than using fixed or static parameters, thereby improving accuracy without requiring manual intervention.
Solution Approach 2:
The patent changes the estimation parameters (coefficients a1, a2, and constant term b) based on the detected movement state. Different sets of parameters are applied for walking versus running states, allowing the system to optimize its estimation accuracy for each specific movement type by using parameter values that are tailored to the characteristics of that state.
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
This approach enhances step length estimation accuracy by distinguishing between walking and running states, improving measurement efficiency and reducing errors, allowing for precise tracking of movement distance in various pedestrian navigation scenarios.
Implementation Method 1
an accelerometer for detecting and outputting an acceleration signal of at least one axis
Data Source
AI summary
An apparatus and method for estimating a step length of a user are provided. The apparatus and method use a step length estimation algorithm, e.g. a step length estimation parameter coefficient, according to a movement state of a user, i.e. whether the movement state is a walking state or a running state. The movement state of the user is determined on the basis of an acceleration variance value of an acceleration signal output from an accelerometer. Accordingly, the apparatus and method prevent errors in step length determinations.