Vehicle Odometry Initial Position Estimation
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Solution Overview
Problem
Conventional position location techniques using Satellite Positioning Systems (SPS) and cellular base stations face challenges in urban environments due to signal reflection, refraction, and multipath, leading to reduced accuracy and long 'time-to-fix' issues, while sensor-assisted navigation techniques struggle to provide an initial position and navigation state at start-up, especially when GPS and GNSS signals are unavailable.
Innovation Solution
The method involves using odometry data from vehicle sensors to estimate an initial position and navigation state by comparing a last known position and heading at a first odometer value to a current odometer value, allowing for dead reckoning at start-up, even when the device is stationary, by storing this information on a mobile device or server and using it to calculate the initial position and navigation state based on the difference between the two values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensor-assisted navigation techniques are used, then navigation accuracy can be improved, but the ability to provide initial position and navigation state at start-up deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-storing the last known position and odometer value before the device needs navigation. When the device is connected to the vehicle, it retrieves this pre-stored information to immediately calculate initial position and navigation state, eliminating the need to wait for GPS signals or process current sensor data from a stationary state.
Solution Approach 2:
The patent uses the stored last known position and odometer value as an intermediary to bridge the gap between vehicle movement and navigation system initialization. By comparing the current odometer value with the stored last known odometer value, the system can calculate displacement and determine initial navigation state without requiring active GPS signals or complex sensor processing at start-up.
2Ease of operation
If SPS and cellular base station techniques are used, then position location capability can be provided, but position accuracy deteriorates in urban environments due to signal reflection, refraction, and multipath
Solution Approach 1:
The patent replaces the electromagnetic signal-based positioning systems (GPS, cellular base stations) with a mechanical measurement system using the vehicle's odometer. By substituting optical/electromagnetic signals with mechanical wheel rotation measurements, the system achieves reliable position tracking in urban environments where signal reflection and multipath effects degrade conventional positioning accuracy.
Solution Approach 2:
The patent introduces the vehicle's odometer as an intermediary measurement device that provides reliable position information independent of external signals. The odometer serves as a self-contained reference that does not suffer from signal reflection or multipath effects, allowing the navigation system to calculate accurate position changes through mechanical measurement rather than electromagnetic signal processing.
Data Source
AI summary
The disclosure relates to estimating an initial position and navigation state associated with a vehicle using odometry and/or other data obtained from the vehicle to support dead reckoning at start-up. In particular, a last known position and last known heading at a first odometer value associated with the vehicle may be stored and compared to a current odometer value after linking a mobile device with the vehicle. The last known position and last known heading may be used to estimate the initial position and navigation state associated with the vehicle based on a difference between the compared odometer values. For example, the estimated initial position and/or navigation state may substantially correspond to the last known position and last known heading if the difference between the odometer values indicates no change, or a non-zero difference may define a radius to limit an estimated error associated with the initial position estimate.