Using a sequential index in terrain-aided navigation

Abstract

Terrain-aided navigation is a database application in which an aeroplane locates itself by matching the height trajectory with a terrain-elevation map on board the aircraft. Without an index a matching algorithm has to be applied to the whole map. This paper shows that an indexing technique, termed the IP-index, can efficiently filter out sub-areas of the map to provide starting positions for the matching algorithm (to improve the efficiency). Performance measurements of the IP-index in terrain-aided navigation are given in this paper. The IP-index is a dynamic indexing technique for large 1-D sequences on the value domain. It supports interpolation assumptions on the sequences, i.e., it can be used to query implicit values in addition to explicit values. It can be implemented by regular ordered indexes such as B-trees.