A vital if unsung hero in the tools we use, LiDAR measures the distance to a target by illuminating the target with laser light and measuring the reflected light with a sensor. Differences in laser return times and wavelengths can then be used to make digital 3D representations of the target. By repeating this in quick succession, the instrument builds up a complex 'map' of the surface it is measuring.
Our LiDAR story began in 2007, when we first deployed a Lockheed Martin WindTracer LiDAR at Frankfurt airport for the European CREDOS project – Crosswind-reduced Separation for Departure Operations to analyse crosswind impact on wake decay.
In specific crosswind conditions, wake vortices are blown away from the trajectory of other aircraft and so no longer pose a safety risk. We used the LiDAR to measure the vortices of departing aircraft, resulting in recommendations to adapt crosswind criteria to reduce or suspend departure wake separation.