Signal detection algorithms for interferometric sensors with harmonic phase modulation: miscalibration of modulation parameters

TL;DR

This paper develops an analytical framework to quantify phase errors caused by miscalibration in harmonic phase modulation for interferometric sensors, comparing conventional and robust demodulation algorithms through modeling.

Contribution

It introduces an analytical method to evaluate phase errors due to parameter miscalibration and compares two demodulation algorithms for improved accuracy.

Findings

Analytical equations accurately predict phase errors.

The 4+1 algorithm shows higher immunity to phase errors.

Modeling confirms the effectiveness of the proposed approach.

Abstract

In the current paper, we have developed an analytical apparatus, allowing to calculate the phase error, produced by miscalibration of modulation parameters. The case of harmonic modulation is considered, the analysis is performed for cases of two parameters miscalibration: amplitude and start phase. Two demodulation algorithms are considered: conventional 4-point algorithm, based on ordinary least squares approach and previously developed 4+1 algorithm with high immunity to phase error, induced by change of target phase on demodulation interval. Predictions, given by developed analytical equations are verified by means of numeric modeling.