Pedestrian Navigation Drift Correction via Hybrid Sensor Fusion
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Solution Overview
Problem
Inertial navigation systems used for pedestrian tracking suffer from drift errors, leading to reduced accuracy over time, and satellite-based GPS systems are unreliable in heavily forested areas or indoors, limiting their applicability for continuous tracking.
Innovation Solution
A hybrid navigation system combining a GPS receiver with inertial instruments and magnetic sensors, which includes a measurement unit mounted on the pedestrian to detect linear and angular accelerations, and a processor to process signals from both sources, using prediction/correction algorithms and recalibration techniques to manage drift and provide accurate tracking even during GPS outages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If inertial navigation systems are used for continuous tracking, then tracking availability is improved, but measurement precision deteriorates due to drift errors over time
Solution Approach 1:
The patent combines GPS receiver with inertial tracking devices to create a hybrid navigation system. The GPS provides absolute position references while inertial sensors provide continuous tracking capability, merging both systems to achieve both high availability and maintained precision through drift correction using GPS references when available
Solution Approach 2:
The system uses feedback by comparing inertial tracking data with GPS position data when GPS signals are available, using the GPS positions to detect and correct drift errors in the inertial system, thereby maintaining measurement precision while preserving continuous tracking availability
2Measurement precision
If GPS systems are used for tracking, then measurement precision is improved, but reliability deteriorates in heavily forested areas or indoors where signals are blocked
Solution Approach 1:
The patent merges GPS receiver with inertial tracking devices to create a hybrid system that uses GPS for high-precision positioning when available, while inertial sensors maintain tracking availability in GPS-denied environments, thus resolving the contradiction between precision and reliability across different operating conditions
Solution Approach 2:
The inertial tracking device serves as an intermediary that bridges the gap during GPS signal blockage, maintaining continuous tracking capability by using dead-reckoning based on previously established position and measured motion, thereby ensuring reliability when GPS precision is unavailable
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 hybrid system effectively tracks pedestrians by reducing drift errors and maintaining accuracy in environments where GPS signals are weak or unavailable, enabling reliable navigation for emergency responders and others in challenging conditions.
Implementation Method 1
inertial units such as accelerometers and gyroscopes have been used in such navigation systems
Implementation Method 2
inertial tracking devices are dead-reckoning systems which keep track of the current location of a subject by estimating the direction and distance traveled
Implementation Method 3
a processor to process signals from both sources, using prediction/correction algorithms and recalibration techniques to manage drift and provide accurate tracking even during GPS outages
Data Source
AI summary
Among other things, first data is received from an inertial tracking device worn by a first person, the first data approximating locations along a first path that was traversed by the first person. Second data is received from an inertial tracking device worn by a second person, the second data approximating locations along a second path, similar to the first path, that is being traversed by the second person. A determination is made about how to guide the second person to reach the first person by using the first data and the second data to correlate locations along the first path and corresponding locations along the second path.