## 6 Conclusions  
This paper successfully demonstrates the efficacy of two-dimensional digital signal processing based on spectra alignment in improving the parameters of the original BGS. This leads to a gain in the accuracy and precision of frequency shift detection at coarse frequency scanning steps and low signal-to-noise ratios. This approach allows for an increase in the length of the fiber sensor and in measurement speed. However, the method has its own drawbacks. The most obvious of these is the high requirement for computing resources. In our opinion, this problem is significant since the method is adapted for fast measurements (coarse frequency step), but in fact, the measurement results can be obtained at this stage only in the post-processing mode.  
Based on this, it is possible to outline the front of the following works aimed at eliminating this drawback:  
1. It is imperative to optimize the algorithm to eliminate duplicate operations.
2. Of particular interest is the alignment of spectra through the use of artificial intelligence rather than the traditional approach of calculating the correlation function.
3. The calculation function is to be transferred to the hardware part of the device.  
It is also important to note that the method has parameters that can be varied. The most significant of them is the number of spectra that fall within the sliding window and, as a result, are subject to alignment. Our findings indicate that the relationship between this value and the accuracy of determining the frequency shift at different signal-to-noise ratios and frequency scanning steps is not straightforward. This was confirmed both in modeling and in the experiment. It is our hope that optimization of the calculations will facilitate more in-depth research in the near future.  
With regard to potential applications, the algorithm can already be used to process signals from reflectometers and analyzers that use a laser source with self-scanning in frequency. Furthermore, a significant improvement in accuracy will be observed when monitoring lines several tens of kilometers long at the far end of the fiber.  
The method is of particular interest for studying optical fibers with high losses, including various special fibers such as photonic crystals, active fibers, and others.  
In our opinion, the potential for using the sensor in extreme conditions, where temperature or deformation (including unpredictable bends) increases the attenuation coefficient of the optical signal in the fiber, which leads to a decrease in SNR and data not falling within the dynamic range of the system, is worthy of further investigation. The utilization of the aforementioned methodology will enhance the functionality of testing units and components, as well as the capacity of entire devices created using new technologies and/or new materials.  
Conceptualization, supervision, writing--Y.K.; validation, formal analysis, writing--F.B.; software, experiment, visualization--A.K. All authors have read and agreed to the published version of the manuscript.  
The authors acknowledge the financial support of the Ministry of Education and Science of the Russian Federation (Agreement No. 075-15-2022-329 of 21 April 2022).  
The experimental data presented in this study are available upon reasonable request from the corresponding author.  
The authors declare no conflicts of interest.