A comparative study of three methods to detect the upper atmospheric wind by DASH

The DASH (Doppler Asymmetric Spatial Heterodyne) is used to detect the upper atmospheric wind velocity by its imaging Fizeau interference fringes. There are two measurement methods: Fourier series method (FSM) and popular transform (FTM). However, accuracy of FTM greatly influenced window function, calculation amount relatively complicated. Four-point algorithm (FPA) for DASH’ s proposed in this paper. contents principle, forward modeling, noise inversion FSM, FPA wholly compared researched. three methods all derived from phase difference transformation fringes with speed 0-100m/s at interval 10m/s simulated, obtained FPA, corresponding errors 2.93%, 4.67% 3.00%,respectively. After artificially adding Gaussian a mean value 0 standard deviation 0.1, after flat field, relative 2.30%, 11.66% 2.27% respectively. noise, speeds 31-39m/s 1m/s 30.1-30.9m/s 0.1m/s FSM FPA. In both cases, 3.55% 4.15% higher than those O(<sup>1</sup>S)557.7nm airglow peak altitude 98 km was photographed our GBAII (Ground based interferometer)-DASH, interferograms zenith angles ° 45 were obtained. Then series, obtain 32.21m/s, 43.55m/s 32.17m/s, From results DASH, we can see that has better detecting wind, simple smaller error.