Iterative Multipath Estimation for GNSS Receiver Accuracy
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Solution Overview
Problem
Global navigation satellite system (GNSS) receivers face significant errors due to multipath interference, particularly in urban environments, where reflected signals arrive delayed and combine with line-of-sight signals, affecting positioning accuracy.
Innovation Solution
A method and system for multipath estimation involving iterative weight estimation operations to subtract estimated multipath components from the received correlation, determining component delays and amplitudes from residual correlations, and processing the lowest-delay or largest-amplitude components with navigation and data decoding circuits to mitigate multipath effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multipath components are estimated and subtracted from the received correlation, then positioning accuracy is improved, but device complexity increases due to iterative weight estimation operations
Solution Approach 1:
The patent segments the multipath mitigation process into distinct iterative operations: initial weight estimation, residual error calculation, satisfaction criterion evaluation, and conditional re-estimation. By dividing the complex mitigation task into manageable sequential steps with clear exit conditions, the system achieves high positioning accuracy while controlling computational complexity through structured process segmentation.
Solution Approach 2:
The patent applies partial action by performing weight estimation only when the satisfaction criterion is not met for the remaining error energy. Instead of continuously estimating all multipath components regardless of necessity, the system selectively re-performs weight estimation operations only when needed to reduce error energy below the threshold, thereby reducing unnecessary computational complexity while maintaining positioning accuracy.
2Reliability
If iterative weight estimation operations are performed to reduce error energy, then multipath mitigation effectiveness is improved, but processing time increases
Solution Approach 1:
The patent implements periodic action through iterative weight estimation operations that are periodically re-executed based on the satisfaction criterion evaluation. The system periodically checks whether the remaining error energy meets the threshold and re-performs weight estimation only when necessary, creating a rhythmic processing pattern that ensures mitigation effectiveness while minimizing unnecessary processing time consumption.
Solution Approach 2:
The patent employs feedback mechanisms by calculating remaining error energy after each weight estimation operation and using this feedback to determine whether to continue or terminate further estimation. The satisfaction criterion acts as a feedback threshold that guides the iterative process, ensuring that processing continues only as long as needed to achieve adequate multipath mitigation, thereby optimizing the balance between effectiveness and processing time.
3Loss of energy
If the second weight estimation operation is performed with more multipath components, then error energy reduction is improved, but computational load increases
Solution Approach 1:
The patent applies dynamics by adaptively adjusting the number of multipath components estimated in the second weight estimation operation based on the remaining error energy from the first operation. The system dynamically determines whether to perform a full second estimation with more components or terminate early, creating a flexible computational approach that reduces error energy efficiently while adapting computational load to the actual mitigation needs of each signal environment.
Data Source
AI summary
A system and method for multipath estimation and mitigation is disclosed. In some embodiments, the method includes performing a first weight estimation operation for a first number of multipath components of a received correlation, calculating a remaining error energy by subtracting a sum of estimated multipath components from the received correlation, determining whether a satisfaction criterion is met for the remaining error energy, and, in response to determining that the satisfaction criterion is not met, performing a second weight estimation operation for a second number of multipath components, the second number being greater than the first number.