Multipath Delay Estimation Using Autocorrelation Analysis
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Solution Overview
Problem
Existing systems face challenges in accurately estimating and canceling multipath delay effects on electromagnetic signals, particularly in air surveillance systems, which lead to position offset and noise in time of arrival measurements due to signal reflections from surrounding environments.
Innovation Solution
A computer system and method that samples electromagnetic signals, calculates autocorrelation functions, identifies relevant abscissa distance values, associates estimation errors, and uses statistical analysis to reduce standard deviation and select average values for accurate multipath delay estimation and cancellation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multipath delay estimation is performed using conventional methods, then time of arrival measurements can be obtained, but position offset and noise are introduced due to signal reflections
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing autocorrelation functions for ideal signals without multipath effects. These pre-computed reference functions are then used to compare against actual received signals, allowing the system to identify and compensate for multipath delay without performing complex real-time calculations. This preliminary preparation enables accurate time of arrival measurements even in the presence of signal reflections.
Solution Approach 2:
The patent introduces an intermediary approach by using autocorrelation functions as a mediator between the received signal and the time of arrival estimation. The autocorrelation function serves as a reference template that captures the characteristics of ideal signals, allowing the system to measure deviations caused by multipath effects and compensate for them, thereby improving both precision and reliability.
2Loss of information
If signal sampling is performed to analyze multipath effects, then estimation data can be obtained, but standard deviation of estimation errors increases
Solution Approach 1:
The patent applies copying by creating multiple simulated versions of the received signal with known multipath characteristics. By generating these copies with controlled variations and analyzing their autocorrelation functions, the system can identify patterns and select the most accurate estimation, thereby reducing standard deviation of errors while retaining essential signal information.
Solution Approach 2:
The patent uses partial action by selecting only the most relevant autocorrelation function values and estimation results from the sampled data. Instead of using all sampled information equally, the system identifies and utilizes the most significant portions that contribute to accurate time of arrival estimation, thereby reducing noise and standard deviation while maintaining measurement precision.
Data Source
AI summary
A method and system for the estimation and correction of the multipath delay is described. The method comprising analyzing the distortion of the autocorrelation function of each single impulse received with that of an ideal impulse, deriving back the variation of the impulse parameters and estimating the effect of the multipart to be taken into account for compensation on the estimation of the time of arrival (TOA) of the electromagnetic signal.