Practical capabilities of ALS systems for helicopter operations at urban terrain

Airborne laser scanning (ALS) of urban regions is commonly used as a basis for subsequent 3D city modeling. As opposed to this, we discuss exam-ples where laser scanners can be used directly for pilot assistance. In this paper we aim at using an existing georeferenced city model to correct errors of the assumed sensor position. Our approach ac-counts for guidance of helicopters or UAVs over urban terrain even at night and during frequent loss of GPS signals. A workflow of real-time capa-ble methods for the segmentation of planar surfac-es within ALS data is described. Matching planar objects, identified in both the on-line segmentation results and the existing city model, are used to cor-rect inaccurate navigational data.