New 3-D laser Doppler velocimeter using cross-bispectral analysis.

A new 3-D laser Doppler velocimeter, which is not sensitive to any random Gaussian noise, is proposed. The information required of the velocity vector under observation is extracted from signals detected simultaneously by three appropriately arranged detectors through their cross-bispectral analysis. This system can detect fairly faint information even when much extraneous noise is present, since the cross-bispectral analysis of simultaneously detected signals works for the effective derivation of the required information and is completely free from any random Gaussian noise. This method is especially suitable for accurate measurement of velocity vectors in a specified plane. The principle, theoretical discussion, construction of the system, and some experimental results are reported.