Range accuracy of a gated-viewing system as a function of the number of averaged images

Primarily, a Gated-Viewing system provides range gated imagery. By increasing the camera delay time from frame to frame, a so-called sliding gates sequence is obtained from which 3-D reconstruction can be done. Scintillation caused by atmospheric turbulence degrades each Gated-Viewing image and thus, the range accuracy that can be achieved with the sliding gates method. By averaging a certain number of images, this degradation can be reduced. In this paper we have studied the influence of the number of averaged images on the range gated imagery and the resulting range accuracy. Therefore, we have combined the Intevac Gated-Viewing detector M506 with a resolution of 640x480 pixels with a pulsed 1.57 µm laser source. The maximal laser pulse energy was 67 mJ. Two reflectance panels at a distance of 2 km were recorded. The plates were positioned diagonal to the line of sight with an angle of about 45 degrees from which the range accuracy was derived. The detector was equipped with a Cassegrain telescope with a focal length of 2032 mm, resulting in a small field of view of only 0.24°x0.18°