When coherent light such as laser beam is projected on a rough target, the scattering field will exhibit random bright spots, known as speckle phenomenon. If the target is in motion, the speckle field also changes over time, and the dynamic characteristics of the speckle field contain the motion information of the target. We refer to the area around the rotation axis of the target as the polar region. In this paper, computer simulation technology is used to study the power spectrum of the dynamic speckle field in the backward and nearby areas when a laser is incident around the polar region direction. The research results indicate that there exists a direction of minimum characteristic frequency of the speckle field near the polar region. When the laser direction is deviated from the rotating axis, the minimum frequency direction is symmetric with respect to the rotation axis of the incident direction, and the minimum characteristic frequency is proportional to the magnitude of the pointing error. The method proposed in this article can be used for remote orientation of the target rotation axis.
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