Configuring an Airborne Laser Scanner for Detecting Airport Obstructions

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To ensure the safety of the national airspace system, the Federal Aviation Administration (FAA) oversees surveying programs with the goal of geolocating vertical features that penetrate 3D Obstruction Identification Surfaces (OIS) around airfields. These OIS are defined mathematically and are based on the layout of the runways, the types of electronic navigation equipment used for each runway, and other factors. Under a series of interagency agreements, the National Geodetic Survey (NGS) is tasked with supplying obstruction survey data to the FAA. Airport obstruction surveys have traditionally been conducted using a combination of photogrammetry and conventional field survey techniques. In this study, we investigate the use of airborne laser scanning technology for this application. Specifically, we examine the effects of varying the forward look angle, laser footprint, flying height, flying speed, scan angle, scan frequency, transmitted power, and receiver sensitivity, as these parameters relate to the detection and measurement of vertical obstructions. We present results of test flights over the Gainesville Regional Airport (GNV) using fourteen different configurations of an Optech ALTM 2050. The results are compared to field-surveyed obstruction data obtained by NGS. Our analysis shows that certain configurations of the airborne laser scanning system notably improve the detection of obstructions. In this study, the best results were obtained using a 20° forward tilt angle and a 0.2 milliradian beam divergence from a flying height of 750 m. With this configuration, all obstructions were detected and the vertical accuracy (RMSE) was 0.88 m when compared to the field-surveyed obstructions.