Using Light Detection and Ranging (LIDAR) methods, in passive or in active remote sensing, can do detection and identification of small targets; in entomology, these methods allow the characterization and the classification of insects. However, it is a challenge to study the physical phenomena, which determine the shape and properties of insect signals. In the field of view, it is actually difficult to make an insect to reproduce or to repeat its random movements. A specimen robot, called phantom insect, able to reproduce insect wings beat has been designed. The phantom insect operating principle has been described. A LIDAR system in passive remote sensing is used to detect and record the phantom insect movements; the detector is a quadrant photodiode that allows getting the insect moving sense using a 1 rn Newtonian telescope. The result allowed establishing effects of flight speed, heading direction and wings beat amplitude on insect signals. The insect signals spectra computing highlights a change in harmonics strengths of spectra.