New Terrain Roughness Index for Update of Profile Based TRN

Y.M. Yoo, S.M. Lee, C.G. Park

Abstract:	We propose a new terrain roughness index that has higher correlation to the navigation solution performance of a profile based TRN (Terrain Referenced Navigation) algorithm than the conventional terrain roughness indexes. Also, false position fix rate is lowered for the same available area when the proposed index is used. In the recent TRN system, the position accuracy has been reported on the order of meters. However, a TRN algorithm sometimes provides a false position when a vehicle flights over featureless terrain. If this false position fix occurs continuously then the TRN solution diverges from the true position. Therefore, some methods are required to mitigate false fix using terrain information such as the terrain roughness index. There are several commercial TRN algorithms, and several definitions of terrain roughness, but the relation between TRN performance and roughness of TRN data is unclear until now. False position fix can occur occasionally not only in a plain but also in a repetitive terrain. Thus, we need to differentiate a distinctive terrain from a repetitive terrain. To discriminate four types of terrain and to find a higher correlation index to the navigation solution of a profile based TRN, we propose a new terrain roughness index calculated by DTED (Digital Terrain Elevation Data) of ROI (Region of Interest). To verify the performance of the proposed terrain roughness index, a simple profile based TRN algorithm is demonstrated in simulations using SRTM (Shuttle Radar Topographic Mission) terrain elevation data of South Korea. Monte Carlo test showed the proposed terrain roughness index has higher correlation to the navigation solution performance of the profile based TRN algorithm than the conventional terrain roughness indexes.
Published in:	Proceedings of the ION 2013 Pacific PNT Meeting April 23 - 25, 2013 Marriott Waikiki Beach Resort & Spa Honolulu, Hawaii
Pages:	381 - 387
Cite this article:	Yoo, Y.M., Lee, S.M., Park, C.G., "New Terrain Roughness Index for Update of Profile Based TRN," Proceedings of the ION 2013 Pacific PNT Meeting, Honolulu, Hawaii, April 2013, pp. 381-387.
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