This paper describes the validation of a wind observer using LiDAR measurements obtained during a wind tunnel experiment. The setup represents a scaled wind farm composed of three actuated and sensorized wind turbine models operating in a turbulent boundary layer. Rotor loads and other wind turbine response data are used to estimate in real time during operation the local wind speed experienced by each wind turbine. The estimates of the rotor inflow produced by the wind observer are compared with flow data measured by two short-range LiDARs. These devices provide fully synchronized scans of the flow along given trajectories. The paper compares the observed and measured wind conditions, demonstrating a good matching between these two independent flow measurement techniques.