Power law noise identification using the LAG 1 autocorrelation by overlapping samples
There are various random errors in the fiber optical gyroscope (FOG) output signal. At the aim of improving its accuracy, it is need to identify the kinds of errors. The most common method for power law noise identification is simply to observe the slope of a log-log plot of the Allan or modified Allan deviation versus averaging time, either manually or by fitting a line to it. The lag 1 autocorrelation method is a new method for power law noise identification that can determine the dominant noise type for all common noise processes, from phase or frequency data, for all averaging factors, in a consistent and analytic manner. This paper describes an improvement of it by overlapping samples, which improves the confidence of the resulting stability estimate at the expense of greater computational time.
The Identification of Satellite Clock Noise Based on LAG1 Autocorrelation of Overlapping Samples
Atomic clock is composed of various components of electronic devices, and its comprehensive effect of the internal and external environment makes it get easily affected by many kinds of noise. The random part of the clock bias is mainly influenced by the noise. The noise identification of atomic clock plays an important role in establishing an accurate random model and the weighting strategy of multi-GNSS. The most common methods for power-law noise identification are slope method, B1 partial factor method, LAG1 autocorrelation function method, and so on. However, these methods have their own defects or shortcomings. In this paper, we propose an improved method of LAG1 autocorrelation function based on overlapping samples to accurately identify the type of noise. By this method, we analyzed the main noise types affecting GPS and BDS satellite clocks. The results showed that the BDS satellite clock is mainly affected by White FM, Flicker FM and Random Walk FM. GPS BLOCK IIA Cs, BLOCK IIA Rb, BLOCK IIR Rb, BLOCK IIR M and BLOCK IIF Cs are mainly affected by the White FM and Flicker PM, and BLOCK IIF Rb is mainly influenced by the White PM, Flicker PM and White FM. The proposed new method based on overlapping sampling of LAG1 autocorrelation function can accurately identify GPS satellite clock noise, because the frequency bias and drift is more stable.
Geological, mineralogical and chemical characterization of Devonian kaolinite-bearing sediments for further applications in the ceramic (tiles) industry in La Paz, Bolivia
Clay minerals are widely distributed in Bolivia; among them, illitic clays are most common in the Altiplano where they are mined for use in the ceramic industry that has been growing in the last few years. In addition to illitic sediments, kaolinitic sediments have been recently discovered in sedimentary units in the Bolivian Altiplano. Residual ball clay occurrences in Devonian sedimentary units were studied as part of this work. Geological mapping and geophysical studies (ERT and GPR) were done for better understanding the origin of the deposits and were part of a preliminary study of the mineral potential to define the relationship with the host rock. Chemical and mineralogical techniques such as X-Ray Diffraction, Scanning Electron Microscopy and Inductively Coupled Plasma analyses were performed in samples from the studied area to verify the presence of kaolinite. Atterberg limits and behaviour of the raw material in ceramic specimens supported by chemical analyses show that this material is suitable for manufacturing tile ceramics. This study provides fundamental knowledge for deposit exploitation and future generation of an alternative source of employment for the inhabitants of Micaya.