Vertical Trajectory Tracking Using Kalman Filter Sensor Fusion
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Solution Overview
Problem
Consumer-grade GPS/MEMS-IMU integration for vertical position determination in outdoor sports is limited by inaccurate altitude measurements, with consumer-grade GPS-derived vertical positional information varying up to 40m due to satellite visibility and multipath signal effects, and real-time kinematic GPS being prohibitively costly.
Innovation Solution
A vertical position and velocity determination system using a cascaded two-step Kalman filter that integrates rate of turn, acceleration, and barometric pressure information, with a tri-axial gyroscope and accelerometer providing orientation and a barometric altimeter for improved accuracy, allowing for accurate estimation of vertical position and velocity without relying on GPS.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If consumer-grade GPS is used for vertical position determination, then the system cost is low, but the measurement precision deteriorates with errors up to 40m
Solution Approach 1:
The patent combines multiple sensing technologies (barometric pressure sensing, accelerometry, and GPS) into an integrated system. The barometric altimeter provides continuous vertical position data, while accelerometers measure vertical acceleration for trajectory calculation. This fusion of sensors compensates for the weaknesses of individual sensors and achieves accurate vertical trajectory tracking without requiring expensive RTK GPS equipment.
Solution Approach 2:
The patent introduces barometric pressure sensing as an intermediary measurement method to bridge the gap between inexpensive consumer GPS and precise vertical trajectory measurement. By using atmospheric pressure as a proxy for altitude measurement, the system achieves meter-level vertical accuracy at consumer-grade cost, effectively mediating between low cost and high precision requirements.
2Ease of operation
If GPS altitude measurement is used, then the system is simple to operate, but the measurement precision deteriorates due to satellite visibility and multipath effects
Solution Approach 1:
The patent introduces barometric pressure sensing as an intermediary measurement method to bridge the gap between inexpensive consumer GPS and precise vertical trajectory measurement. By using atmospheric pressure as a proxy for altitude measurement, the system achieves meter-level vertical accuracy at consumer-grade cost, effectively mediating between low cost and high precision requirements.
Solution Approach 2:
The patent replaces the radio wave-based GPS altitude measurement system with a pressure-based measurement system. By substituting electromagnetic signal processing with atmospheric pressure sensing, the system avoids the inherent limitations of GPS (satellite visibility, multipath effects) while maintaining ease of operation with consumer-grade devices.
3Measurement precision
If real-time kinematic GPS is used to improve vertical accuracy, then the measurement precision improves, but the device complexity and cost increase prohibitively
Solution Approach 1:
The patent employs inexpensive, consumer-grade sensors (barometric altimeter, accelerometers, and standard GPS receiver) that can be integrated into affordable wearable devices. Rather than relying on complex RTK GPS infrastructure, the system uses multiple low-cost sensors whose data is fused through algorithms to achieve high accuracy, making precision trajectory tracking accessible to recreational athletes.
Solution Approach 2:
The patent combines multiple sensing technologies (barometric pressure sensing, accelerometry, and GPS) into an integrated system. The barometric altimeter provides continuous vertical position data, while accelerometers measure vertical acceleration for trajectory calculation. This fusion of sensors compensates for the weaknesses of individual sensors and achieves accurate vertical trajectory tracking without requiring expensive RTK GPS equipment.
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
The system achieves vertical trajectory tracking errors of about 26.9 cm to 28.1 cm and jump height/drop determination errors of 2.9 cm to 5.8 cm, sufficient for recreational and outdoor athletic measurements, offering improved accuracy and cost-effectiveness compared to traditional GPS methods.
Implementation Method 1
a cascaded two-step Kalman filter that integrates rate of turn, acceleration, and barometric pressure information, with a tri-axial gyroscope and accelerometer providing orientation and a barometric altimeter for improved accuracy
Implementation Method 2
a tri-axial gyroscope and accelerometer providing orientation
Implementation Method 3
a tri-axial gyroscope and accelerometer providing orientation and a barometric altimeter for improved accuracy
Data Source
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AI summary
This disclosure provides a vertical position and velocity determination system for inertial measurement unit (IMU) integrated with a barometric altimeter in the same device (IMU-baro). The system includes a rate of turn input connected to receive a measured IMU-baro rate of turn; an acceleration input connected to receive a measured IMU-baro acceleration; a barometric pressure input connected to receive a measured IMU-baro altitude; a first Kalman filter connected to the rate of turn input and to the acceleration input to estimate a roll and pitch of the IMU-baro based on the measured IMU-baro rate of turn and the measured IMU-baro acceleration; and a second Kalman filter connected to the acceleration input, to the barometric pressure input, and to the first Kalman filter