3D ray-tracing for intra-vehicle environments

In order to develop a wireless communication system that could be used for all types of aircraft sensor networks, the severe multipath channel found inside aircrafts must be well defined. This multipath channel is much more complex than usual outdoor/indoor channels and thus far, research has been limited to a basic stochastic model for the aircraft environment called hyper-Rayleigh (Frolik, 2007). This model has been useful for a general understanding of the aircraft environment; however, in preliminary simulations this model was not accurate enough to describe MIMO performance for a range of fading channels (Magleby and Furse, 2008). The next level of accuracy in modeling is site-specific modeling, also known as ray-tracing. Due to the 3D reflective surface of the fuselage, ray-tracing must be implemented in a 3D simulation in order to fully describe the aircraft environment. This paper discusses a 3D ray-tracing modeler (Lim et al., 2009) that has been adapted to simulate the reflections that occur inside an aircraft fuselage, which is closely related to the environment in a bus or tunnel. Preliminary research has shown that MIMO systems take advantage of extreme multipath environments found in aircraft and provide more consistent channel capacity than SISO systems. Thus the software is extendable to simulate both SISO and MIMO antennas. To validate and calibrate the ray-tracing software, it was compared with preliminary measurements taken in a tunnel, and other measurements from a bus and aircraft. The MIMO output of the simulation software will be used in future research to create the channel matrix that is needed for previously developed MIMO optimization software (Landon, 2007).