High-precision adaptive filtering FBG spectral rapid peak searching method

Abstract

The invention discloses a high-precision adaptive filtering FBG spectral rapid peak searching method. The method is characterized by according to an acquired central wavelength lambda0 of an FBG spectrum under an indoor environment, cutting FBG spectrum data to acquire an FBG spectrum data subset; carrying out energy maximum detection PMax on the FBG spectrum data subset and taking lambdaMax as a center and shifting 2.5nm to left and right sides respectively; selecting and constructing a spectrum energy array P[i] which participates in peak searching; carrying out adaptive zero phase filtering on the spectrum energy array P[i], calculating an optimal cutoff frequency, carrying out low pass filtering and acquiring a filtered array p<'>[i]; and using a Gauss fitting algorithm to carry out accurate peak searching on the filtered spectrum energy array p<'>[i] and acquiring an FBG spectrum accurate peak point. By using the method, the algorithm is simple and rapid, a participated peak searching data amount is less, the method is not influenced by a local spectrum noise and signal distortion, peak searching stability is good and precision is high. Under an extreme environment, FBG spectrum energy attenuation is intense so that a signal to noise ratio is low and peak searching can not be performed. By using the method, the above problem is solved. The method has positive practical significance for increasing measurement precision of a fiber grating sensor under a conventional usage environment and the extreme environment.

Description

technical field [0001] The invention belongs to the technical field of optical fiber sensing, and in particular relates to a fast peak-finding method for high-precision self-adaptive filtering FBG spectrum. Background technique [0002] With the continuous improvement of my country's spacecraft model development requirements, there is an urgent need to measure the temperature and strain of the spacecraft and monitor the thermal deformation of the structure in real time under the simulated space vacuum thermal environment on the ground. Optical fiber multi-parameter composite sensing technology can meet the requirements of vacuum thermal test applications for the entire star and its large exposed structural parts (such as mesh antennas, truss structures, solar wings, robotic arms, etc.). Fiber Bragg Grating (FBG) sensor is currently a research hotspot in the field of fiber optic sensors, and it is also the most extensive and most marketable fiber optic sensor in sensor resear...

AI Technical Summary

Problems solved by technology

[0004] In practical applications, due to the influence of various noises, especially the influence of the extreme space environment, the FBG spectrum is easily disturbed, which changes the size or position of the actually measured spectral peak, directly affecting the accuracy and repeatability of wavelength detection

At present, the low-pass digital filtering method is commonly used to preprocess the spectral data for noise reduction, that is, before performing peak-finding processing on the FBG spectral data, first use the low-pass digital filtering method to perform noise reduction processing on the spectral data, and the low-pass cut-off frequency is based on human experience Select it and keep it constant for fixed use. When the noise in the optical path changes, the low-pass cutoff frequency remains unchanged, and the filtering effect becomes worse.

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