A worldwide SRTM terrain database suitable for aviation use

Abstract

In the past Jeppesen has built and distributed worldwide terrain models for several Terrain Awareness and Warning Systems (TAWS) avionics clients. The basis for this model is a 30 arc-second NOAA Globe dataset with higher resolution data used where available (primarily in the US). On a large scale however these terrain models have a 900m (3000ft) resolution with errors that can often add up to 650m (1800ft) vertically. This limits the use of these databases to current TAWS systems and is deemed unusable for other aviation applications like SVS displays that require a more resolute and accurate terrain model. To overcome this deficiency, the target of this project was to develop a new worldwide terrain database providing a consistent terrain model that can be used by current (TAWS) and future applications (e.g. 2D moving maps, vertical situation displays, SVS). The basis for this project is the recently released SRTM data from NGA that provides a more resolute, accurate and consistent worldwide terrain model. The dataset however has holes in the peak and valley regions, desert, and very flat areas due to irrecoverable data capture issues. These voids have been filled using new topography algorithms developed in this project. The error distribution of this dataset has been analyzed in relation to topography, acquisition method and other factors. Based on this analysis, it is now possible to raise the terrain a certain amount, such that it can be guaranteed that only a certain number of real terrain points are higher than the data stored in the terrain database. Using this method, databases for designated confidence levels of 10 -3 , 10 -5 and 10 -8 -called TerrainScape level 1 -3 -have been generated.The final result of the project is a worldwide terrain database with quality factors sufficient for use in a broader range of civil aviation applications.