A helicopter terrain following system for terminal area operations

1985 ◽  
Author(s):  
F. KILMER ◽  
R. KILMER ◽  
H. SWENSON ◽  
A. WOODWARD
Keyword(s):  
Terrain Following ◽  
Terminal Area

scholarly journals Performance of Adaptive Unstructured Mesh Modelling in Idealized Advection Cases over Steep Terrains

Atmosphere ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 444 ◽  
Author(s):  
Jinxi Li ◽  
Jie Zheng ◽  
Jiang Zhu ◽  
Fangxin Fang ◽  
Christopher. Pain ◽  
...  
Keyword(s):  
Unstructured Mesh ◽  
Computational Cost ◽  
Adaptive Mesh ◽  
Galerkin Finite Element Method ◽  
Adaptive Meshes ◽  
Galerkin Finite Element ◽  
Computational Costs ◽  
Cut Cell ◽  
Discontinuous Galerkin Finite Element ◽  
Terrain Following

Advection errors are common in basic terrain-following (TF) coordinates. Numerous methods, including the hybrid TF coordinate and smoothing vertical layers, have been proposed to reduce the advection errors. Advection errors are affected by the directions of velocity fields and the complexity of the terrain. In this study, an unstructured adaptive mesh together with the discontinuous Galerkin finite element method is employed to reduce advection errors over steep terrains. To test the capability of adaptive meshes, five two-dimensional (2D) idealized tests are conducted. Then, the results of adaptive meshes are compared with those of cut-cell and TF meshes. The results show that using adaptive meshes reduces the advection errors by one to two orders of magnitude compared to the cut-cell and TF meshes regardless of variations in velocity directions or terrain complexity. Furthermore, adaptive meshes can reduce the advection errors when the tracer moves tangentially along the terrain surface and allows the terrain to be represented without incurring in severe dispersion. Finally, the computational cost is analyzed. To achieve a given tagging criterion level, the adaptive mesh requires fewer nodes, smaller minimum mesh sizes, less runtime and lower proportion between the node numbers used for resolving the tracer and each wavelength than cut-cell and TF meshes, thus reducing the computational costs.

scholarly journals Integrated Robotic systems for Humanitarian Demining

10.5772/5694 ◽  
2007 ◽  
Vol 4 (2) ◽  
pp. 24 ◽  
Author(s):  
E. Colon ◽  
G. De Cubber ◽  
H. Ping ◽  
J-C Habumuremyi ◽  
H. Sahli ◽  
...  
Keyword(s):  
Data Acquisition ◽  
Lessons Learned ◽  
Mine Detection ◽  
Detection Systems ◽  
Visual Positioning ◽  
Humanitarian Demining ◽  
Typical Data ◽  
Terrain Following ◽  
Software Interfaces ◽  
Future Work

This paper summarises the main results of 10 years of research and development in Humanitarian Demining. The Hudem project focuses on mine detection systems and aims at provided different solutions to support the mine detection operations. Robots using different kind of locomotion systems have been designed and tested on dummy minefields. In order to control these robots, software interfaces, control algorithms, visual positioning and terrain following systems have also been developed. Typical data acquisition results obtained during trial campaigns with robots and data acquisition systems are reported. Lessons learned during the project and future work conclude this paper.

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