where [ ] signifies the first integer inferior to the number and - .Coherence function and explicit decompositionThe variation of the coherence function matrix resembles that of the auto-PSD matrix. Exceptthat in Period 2, the vehicle is operating through the static points on the bridge, so the relativeposition among the vehicle and the static points varies with time. The coherence function matrix of the three periods are presented in Equation (17), Equation (18) and Equation (19),respectively