Using airborne GNSS receivers to detect atmospheric turbulence

A methodology for estimating turbulence intensity from GNSS-aircraft occultations is presented. The theoretical underpinnings are from standard weak-scattering theory for electromagnetic wave propagation in random media. These techniques are modified to deal with a transmitter and receiver moving relative to each other. A simulation method is then used to evaluate the sensitivity of the intensity estimates to two other unknown parameters, the turbulence length scale and the distance of the turbulence from the receiver. It is shown that the estimation is highly sensitive to the latter and relatively insensitive to the former. An iterative technique is presented that uses estimates of the distance parameters to improve the intensity estimation. It is shown that given the assumptions in the problem, the iterative technique provides relatively accurate estimates of the turbulence intensity parameter.