Correlation Mode Switching for GPS Multipath Resolution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing GPS devices face limitations in multipath mitigation due to narrowband correlation modes with limited code phase hypothesis resolution and sampling rates, which fail to distinguish short multipath components effectively, leading to code phase detection errors.
Innovation Solution
The method involves selectively initiating different correlation modes based on measured signal strength, using non-uniform autocorrelation functions to distinguish between direct and multipath signal components, and establishing code phase measurement data, allowing for higher sampling rates and increased multipath resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If narrowband correlation modes are used, then device complexity and power consumption are reduced, but multipath resolution and code phase detection accuracy deteriorate
Solution Approach 1:
The system dynamically switches between narrowband and wideband correlation modes based on signal conditions. The correlation mode is adjusted in real-time according to measured signal strength and multipath environment characteristics, allowing the device to optimize between complexity and precision adaptively rather than being fixed in one mode
Solution Approach 2:
The patent changes key parameters including sampling rate (from narrowband to wideband), correlation bandwidth, and code phase hypothesis spacing. By adjusting these parameters based on signal conditions, the system achieves higher multipath resolution when needed while maintaining lower complexity when signal conditions permit
2Measurement precision
If wideband correlation modes with high sampling rates are used, then multipath resolution and code phase detection accuracy are improved, but device complexity and power consumption increase
Solution Approach 1:
The system transitions from static to dynamic operation by continuously monitoring signal conditions and switching correlation modes accordingly. Wideband mode is activated only when signal strength and multipath characteristics warrant the additional complexity, otherwise narrowband mode is used
Solution Approach 2:
The correlation processing is segmented into multiple modes (narrowband and wideband) with different complexity levels. Each mode is optimized for specific signal conditions, allowing the system to divide the overall processing task into manageable segments based on operational requirements
3Use of energy by stationary object
If narrowband correlation modes are used, then power consumption is reduced, but ability to distinguish short multipath components deteriorates
Solution Approach 1:
The system adaptively adjusts power consumption by switching between correlation modes based on multipath environment detection. When short multipath components are detected or suspected, wideband mode is activated to preserve discrimination capability, otherwise narrowband mode reduces power consumption
4Productivity
If code phase hypothesis spacing is increased, then processing speed is improved, but code phase detection precision deteriorates
Solution Approach 1:
The code phase hypothesis spacing is dynamically adjusted based on the correlation mode. In wideband mode, finer spacing is used to achieve precise code phase measurements, while in narrowband mode, coarser spacing is acceptable and reduces processing burden
Solution Approach 2:
Different hypothesis spacing strategies are applied locally to different correlation modes. Each mode has optimized spacing appropriate to its bandwidth and resolution characteristics, rather than using a uniform spacing approach across all operating conditions
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Methods and apparatus are provided for use in devices operatively enabled to perform waveform correlation result processing.