Yes, with careful experiment you will be able to obtain oxygen positions and calculate tilting from that. However, I would recommend to make neutron diffraction if you have such opportunity.

Thanks to Alexander B. Missyul. What are the parameters to check the quality of experiments if we used powder X-ray diffraction. We don't have access to neutron but the results are comparable with the published results. Please suggest to confirm our results on oxygen octahedra tilting and Quantitative Phase analysis if we have more than one crystal symmetries of single compound. 

any tilting of oxygen octahedra away from the all-parallel orientation will break the cubic symmetry, thereby leading to tetragonal or orthorhombic structures. This distortion can be measured by any diffraction technique if it extends over larger regions.

Thanks sir for your valuable comments. I also have tried with Rietveld refinement of xrd patterns.