Abstract:
The mean velocity of the atmospheric wind is an
important parameter in characterizing the turbulence above
an astronomical telescope. Real-time wind velocity
measurement is exceedingly essential to update the design
metrics of the adaptive optics system periodically to improve
the dynamic performance. A Shack Hartmann Wavefront
Sensor (SHWS), which is generally used in astronomical
telescope adaptive optics systems for wavefront sensing, can
be simultaneously used for wind speed estimation and this
means of wind speed estimation needs special attention due
to the ease of its implementation. In this paper, we discuss in
elaborate the experimental evaluation of the wind
measurement from the calculation of the two dimensional
cross-correlation function. Adopting the peak technique, we
find that the identification of the peak can be made accurate
by using the computation cost effective 3-point parabolic
interpolation technique, which is shown to behave close to
the 3-point Gaussian interpolation. Also, it is shown that the
time interval chosen for the calculation of the cross-correlation
plays a vital role in optimal performance. For small time
interval case, the interpolation techniques do not yield correct
results. In this case, it is shown that the iteratively weighted
center of gravity algorithm is more suitable
