The photography shows this target was a drum measuring 0.6 meters wide by 1 meter tall. The original sonar image being stretched in the length track (causing the 8 meter measurement) can be attributed to two things. First, the AUVs have a continuous heading wobble of plus/minus .75 degrees and, second, the acoustic beam spreading through the water. These distortions increase with distance from the AUVs and this target was originally imaged 500 meters from the vehicle. We are working on the heading oscillation which was originally plus/minus 3 degrees but the acoustic beam spreading is unavoidable.