Resolution-enhancement and sampling error correction based on molecular absorption line in frequency scanning interferometry

2018 ◽  
Vol 416 ◽  
pp. 214-220 ◽  
Author(s):  
Hao Pan ◽  
Xinghua Qu ◽  
Chunzhao Shi ◽  
Fumin Zhang ◽  
Yating Li
Keyword(s):  
Error Correction ◽  
Absorption Line ◽  
Sampling Error ◽  
Resolution Enhancement ◽  
Molecular Absorption ◽  
Frequency Scanning ◽  
Frequency Scanning Interferometry

Submegahertz frequency stabilization of a terahertz quantum cascade laser to a molecular absorption line

2010 ◽  
Vol 96 (7) ◽  
pp. 071112 ◽  
Author(s):  
H. Richter ◽  
S. G. Pavlov ◽  
A. D. Semenov ◽  
L. Mahler ◽  
A. Tredicucci ◽  
...  
Keyword(s):  
Absorption Line ◽  
Quantum Cascade Laser ◽  
Frequency Stabilization ◽  
Molecular Absorption ◽  
Quantum Cascade

scholarly journals An efficient method for the compensation of dispersion mismatch in the frequency-scanning interferometry

2021 ◽  
Author(s):  
Qiang Zhou ◽  
Tengfei Wu ◽  
Yang Liu ◽  
yue shang ◽  
Jiarui Lin ◽  
...  
Keyword(s):  
Efficient Method ◽  
Frequency Scanning ◽  
Frequency Scanning Interferometry

scholarly journals Limits on the Variation of Physical Constants Derived from Molecular Absorption Lines

1999 ◽  
Vol 183 ◽  
pp. 167-167 ◽  
Author(s):  
T. Wiklind ◽  
F. Combes
Keyword(s):  
Absorption Line ◽  
High Redshift ◽  
Absorption Lines ◽  
Frequency Resolution ◽  
Radio Lines ◽  
Molecular Absorption ◽  
Diagnostic Application ◽  
Physical Constants ◽  
Resonance Transitions ◽  
Electronic Resonance

A potential diagnostic application of molecular rotational absorption lines at high redshift is to test the invariance of physical constants. This can be done by comparing the observed redshifted frequency of a molecular absorption line with redshifted lines from other types of transitions such as the 21cm hyperfine transition or electronic resonance transitions. In order to set stringent limits, it is necessary to achieve the greatest possible frequency resolution. This makes radio lines well suited for this purpose.

scholarly journals Vibration Compensation of the Frequency-Scanning-Interferometry-Based Absolute Ranging System

2019 ◽  
Vol 9 (1) ◽  
pp. 147 ◽  
Author(s):  
Fu-Min Zhang ◽  
Ya-Ting Li ◽  
Hao Pan ◽  
Chun-Zhao Shi ◽  
Xing-Hua Qu
Keyword(s):  
Standard Deviation ◽  
Vibration Frequency ◽  
Phase Modulation ◽  
Vibration Velocity ◽  
Sinusoidal Vibration ◽  
Vibration Effect ◽  
Frequency Scanning ◽  
Blind Area ◽  
Frequency Scanning Interferometry ◽  
Vibration Compensation

The frequency-scanning-interferometry-based (FSI-based) absolute ranging technology is a type of ranging technology possessing a high precision and no ranging blind area, so it can be used for non-cooperative targets. However, due to a tiny movement of a target, the Doppler shift and the phase modulation are introduced into the beat signal which results in ranging accuracy decrease. In order to solve this problem, first the model of vibration effect is established, and then the beat signals of two adjacent scanning periods are processed to produce a signal that is immune to vibration. The proposed method is verified by the experiments, and the experimental results show that the effect of vibration compensation is better for the target with a lower vibration velocity and at a lower vibration frequency (lower than 6 Hz). When the target is subjected to a sinusoidal vibration with an amplitude of 10 μm at a frequency of 1 Hz, by using the proposed method the standard deviation is reduced from 775 to 12 μm. Moreover, in the natural environment, by using vibration compensation the standard deviation is reduced from 289 to 11 μm.

Sampling Error Correction Evaluated Using a Convective-Scale 1000-Member Ensemble

2019 ◽  
Vol 148 (3) ◽  
pp. 1229-1249 ◽  
Author(s):  
Tobias Necker ◽  
Martin Weissmann ◽  
Yvonne Ruckstuhl ◽  
Jeffrey Anderson ◽  
Takemasa Miyoshi
Keyword(s):  
Sensitivity Analysis ◽  
Data Assimilation ◽  
Error Correction ◽  
Degrees Of Freedom ◽  
Sampling Error ◽  
Lookup Table ◽  
Ensemble Prediction ◽  
Sampling Errors ◽  
Convective Scale ◽  
The Impact

Abstract State-of-the-art ensemble prediction systems usually provide ensembles with only 20–250 members for estimating the uncertainty of the forecast and its spatial and spatiotemporal covariance. Given that the degrees of freedom of atmospheric models are several magnitudes higher, the estimates are therefore substantially affected by sampling errors. For error covariances, spurious correlations lead to random sampling errors, but also a systematic overestimation of the correlation. A common approach to mitigate the impact of sampling errors for data assimilation is to localize correlations. However, this is a challenging task given that physical correlations in the atmosphere can extend over long distances. Besides data assimilation, sampling errors pose an issue for the investigation of spatiotemporal correlations using ensemble sensitivity analysis. Our study evaluates a statistical approach for correcting sampling errors. The applied sampling error correction is a lookup table–based approach and therefore computationally very efficient. We show that this approach substantially improves both the estimates of spatial correlations for data assimilation as well as spatiotemporal correlations for ensemble sensitivity analysis. The evaluation is performed using the first convective-scale 1000-member ensemble simulation for central Europe. Correlations of the 1000-member ensemble forecast serve as truth to assess the performance of the sampling error correction for smaller subsets of the full ensemble. The sampling error correction strongly reduced both random and systematic errors for all evaluated variables, ensemble sizes, and lead times.

Sign in / Sign up

Export Citation Format

Share Document