Methods for optical adjustment in lidar systems.

In a lidar system, both a well-adjusted receiving telescope and an accurate transmitter-receiver alignment are essential for obtaining reliable data, but usually these are time consuming and difficult to accomplish, especially when the optical axis of the telescope is fixed. To solve these problems, we present a novel method, to our knowledge, for the receiving telescope adjustment, which is carried out mainly with a commercial laser plummet. A simple, fast alignment procedure is also described. These are tested by adjustment of the Fe-resonance fluorescence lidar system of Wuhan University and proved to be effective and convenient. The lidar system is applied to monitor the Fe layer in the mesosphere, leading to continuous retrieval of the iron density profiles with fine spatiotemporal resolution.