Terrain-Referenced Positioning Using Airborne Laser Scanner

This paper describes a high-accuracy, prototype terrain-referenced positioning system that uses an airborne laser scanner (ALS) as the terrain sensor. Meter-level position estimation is performed using a batch processing technique to search for the highest level of agreement between georeferenced ALS data and a digital elevation model (DEM) with approximately 2 m postspacing and elevation accuracy on the order of 30 cm root mean square (RMS). The prototype system uses an ALS with a 33,333 Hz pulse rate, providing a horizontal measurement resolution of less than 5 m. Exhaustive and gradient-based methods are investigated as part of the batch processing search technique, which calculates the most likely user position within a spatial search area referred to as the sum-of-squared-error (SSE) surface. The performance of the prototype system is evaluated with data collected using the National Aeronautics and Space Administration (NASA) Dryden DC-8 Airborne Laboratory.