I guess, to find the azimuth is to find the height of each one of the three pyramids displayed in the pictures. The heights will provide you with coordinates in 3D (x, y, z) and you can have the transformation coordinates.

Viara Van Raad Thanks for the answer. I have the derivation of the formulas of distance using 3D coordinate system. I had a question related to implementing the Von Mises distribution which formula i have given in the picture. As in our Channel modeling we have three models to compare the result. 1st one in which we keep the values of rays etc infinite (reference model) . The second one in which we set the values of the rays to any finite number (Simulation Model). And the third one is the Simulation result which (Measurement Data) from certain experiment. So my question was when we set the value of rays such as 3 in above picture. How are we suppose to obtain the Von- Mises distribution and how to fit it in the Channel impulse response equation. If Someone can elaborate i would be very obliged. Regards

Ok, but this is about setting a preliminary model and working with this model. I found you a research article that you may consider relevant. The mathematics is pretty "heavy" but in my own words, you should obtain "predicted" set of coordinates of rays that belong to your simulated model of Von M. and then you should run experiments to use multivariatve analyses if a 3D point belongs/or not to your simulated model (i.e. set of your preliminary 3D points). Of course, you should place a tolerance (say 5%) to establish hit/miss in the model test. Here is an article: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.511.6330&rep=rep1&type=pdf