Komatsu, S., Imai, S., Taguchi, K., and Kashiwa, T., "Incoming Wave Estimation Characteristics by MUSIC Method Using a Virtual Array Antenna in Urban Reception Conditions," SAE Int. J. Passeng. Cars – Electron. Electr. Syst. 9(1):123-133, 2016, https://doi.org/10.4271/2016-01-0077.
We developed “Two-Stage Method” that makes it possible to evaluate the automotive suitability of FM receivers by generating a virtual radio wave environment on a PC. The major technological challenge for the Two-Stage Method was reproducing an actual radio wave environment on PC. It was necessary to estimate the characteristics of the FM radio wave environment in tests using the Multiple Signal Classification (MUSIC) method. However, when the MUSIC method is applied to FM reception, restrictions in factors including the number of array antenna elements and the occupied bandwidth result in issues of separation performance in relation to multipath waves in urban environments.We therefore developed a MUSIC Method using a virtual array antenna, making it possible to create combinations of numbers of array and sub-array elements as desired, thus boosting multipath wave separation performance. This development was reported at the 2015 SAE World Congress.However, this report did not offer verification of the accuracy of the method in estimating radio wave environment characteristics.The research discussed in this paper therefore assumed cases of non-modulation and maximum modulation of the occupied bandwidth of the FM broadcast waves during estimation of delay time, and studied the effect of the occupied bandwidth in an urban environment. In addition, the reception environment in an actual urban area was modeled using 3D maps and ray tracing, and the arrival directions of FM waves were calculated numerically, verifying the accuracy of MUSIC method estimation. This demonstrated the usefulness and novelty of the research.