Inertial Sensor Activation for Dead Reckoning Positioning
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Solution Overview
Problem
Existing location-based systems for cellular devices face challenges in determining position when GPS is unavailable or inaccurate, particularly in areas with weak satellite signals, leading to difficulties in providing reliable location-based functionality.
Innovation Solution
The system employs inertial sensors and dead reckoning techniques, activating them when the device is at an anchor location to determine position, and deactivating them when not needed to conserve energy, while using crowd-sourced data from Wi-Fi and cell tower signals to extend positioning capabilities into GPS-deprived areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If inertial sensors are continuously activated for dead reckoning, then position determination accuracy is improved, but device energy consumption increases
Solution Approach 1:
The system periodically activates inertial sensors only when the device is at an anchor location to perform dead reckoning position determination, rather than continuously operating them. This periodic activation based on location triggers maintains position accuracy when needed while significantly reducing overall energy consumption of the device.
Solution Approach 2:
The system uses crowd-sourced data from Wi-Fi and cell tower signals to automatically identify when the device is at an anchor location, triggering inertial sensor activation without requiring continuous sensor operation or manual intervention. This self-service approach optimizes the balance between position accuracy and energy usage.
2Adaptability or versatility
If GPS is used for position determination, then location-based functionality is provided, but position cannot be determined in areas with weak satellite signals
Solution Approach 1:
The system introduces crowd-sourced data from Wi-Fi and cell tower signals as an intermediary to identify anchor locations where GPS is available. This intermediary data source enables the system to determine when to activate inertial sensors for dead reckoning, providing reliable position determination in GPS-denied areas while maintaining overall system versatility.
Solution Approach 2:
The system pre-identifies anchor locations using crowd-sourced Wi-Fi and cell tower data before GPS signal availability changes. This preliminary identification allows the system to proactively switch to dead reckoning mode using inertial sensors when GPS becomes unavailable, ensuring continuous reliable position determination.
3Reliability
If inertial sensors are activated at anchor locations for dead reckoning, then position determination is enabled in GPS-deprived areas, but device complexity increases
Solution Approach 1:
The system uses a unified approach where inertial sensors serve multiple functions: they are activated at anchor locations for dead reckoning in GPS-deprived areas and can also contribute to position estimation when GPS is available. This multi-functional use of sensors reduces overall system complexity compared to having separate systems for different operating conditions.
Data Source
AI summary
An identification is made as to when a device is at an anchor location, which can be a proximity zone along an edge of a dead zone or a location where a signal from a beacon is detected. In response to the device being at the anchor location, one or more inertial sensors can be activated and data from the one or more inertial sensors collected to determine a position of the device using dead reckoning. Alternatively, in response to the device being at the anchor location, a determination is made as to when to deactivate one or more inertial sensors from which data is collected to determine the position of the device using dead reckoning.