I had a client talk to me about how to calculate the pulse accuracy. In the industry we do a lot of testing of the relative accuracy and the absolute accuracy as it relates to a complete data set but what do we do to test the actual accuracy of the pulse and the returns from the pulse. I saw a presentation given by a gal named Nora who was at The Ohio State University and now works for FUGRO. She and her professor did an extensive study along a highway corridor using targets to test the accuracy of the returns. When I used to help make and develop systems we used surveyed Targets at .5 miles, 1.0 miles and 2.0 miles on a horizontal test range, located on a very flat plateau to measure the accuracy of the return and calculate the “laser zero” or location of the point of origination of the laser, so that the length of the pulse return can be calculated very accurately. I was wondering if anyone has additional information on how they measure the accuracy of the pulse or return of Laser in a LiDAR system and does this get checked every so often. Is there any potential issues with this and How do you quantify the atmospheric characteristics with a data set in different climate regions and if you feel this is really an issue or not and why? It was very apparent to me that flying in very humid conditions the result varied in relationship to flying in very dry regions. Just looking to see what folks are doing in this area or if it really matters to anyone because I can see why he asked this question.