Statistical analysis of angle-of-arrival on 4.1 km line-of-sight laser link at 0.83 μm across central London

Statistics from 18 months of measurements of clear air angle of arrival fluctuations on an 0.83 μm line-of-sight laser link propagating on a 4.1 km path across central London are presented. Analysis of the probability density function estimates of angle of arrival for a range of values of the structure parameter C_n ² shows virtually no departure from a Gaussian distribution. The standard deviation of the angle of arrival increases as the strength of turbulence increases with values up to 100 μrad. A range of angle of arrival of up to ±300 μrad was measured