Principle and performance analysis of the Levenberg Marquardt algorithm in WMS spectral line fitting

TL;DR

This paper systematically analyzes how the Levenberg Marquardt algorithm's parameters and initial estimates affect its effectiveness in wavelength modulation spectroscopy for trace gas detection.

Contribution

It provides a detailed analysis of the factors influencing the Levenberg Marquardt algorithm's performance in WMS spectral line fitting.

Findings

Number of parameters impacts accuracy

Initial estimation errors limit retrieval precision

Simulation confirms key factors affecting effectiveness

Abstract

Calibration free wavelength modulation spectroscopy (WMS) is an efficient technique for trace gas monitoring. It is widely used due to its resistance to light intensity fluctuations, strong suppression of low frequency noise, fast response time and excellent environmental adaptability. The calibration free WMS often employs the Levenberg Marquardt algorithm for spectral fitting to retrieve gas characteristics. However, to the best of our knowledge, an analysis of the main factors affecting the operational effectiveness of the Levenberg Marquardt algorithm in calibration free WMS has merely been reported. In this paper, we have systematically analyzed the Levenberg Marquardt algorithm s operating mechanism in WMS 2f/1f. The simulation results show that the number of parameters and initial parameter estimated errors are the main factors limiting the retrieval accuracy of the algorithm.