This paper considers design of a web-portal for the validation of behavior of GNSS applications in different environments. The tool provides the positioning performance analysis and a comparison to benchmark devices. Web-portal incorporates a 3D synthetic data generator to compute the propagation and the reception of radio-navigation signals in a 3D virtual environment. This radio propagation simulator uses ray-tracing to calculate interactions between the GNSS signal and the local environment. For faster execution on a GPU platform, the simulator uses BVH optimization. The work is verified in field trials and by using reference software.