Abstract
Spacecraft descent-to-landing navigation often includes the use of a slant-range measurement, the distance from the spacecraft to a surface along the off-nadir pointing direction of the sensor. Modeling a slant range sensor requires a reference surface, approximations of which include spherical and ellipsoidal surfaces, spherical harmonic models, and topographical maps based on prior reconnaissance data. For the spherical and ellipsoidal reference surfaces, a closed-form solution of the slant-range measurement exists. However, these approaches are inaccurate with respect to the true surface. This paper develops a method to implement digital elevation maps of a given surface to create a topography-based model of a slant-range sensor. Using the position and pointing direction of the spacecraft, the complexity of the problem is reduced from a fully three-dimensional space to a two-dimensional interpolation. The result is a slant-range solution that takes topographical effects into consideration as opposed to a simple reference surface. The algorithm is tested and shows a clear improvement in solution accuracy over simplistic surface models and illustrates that the level of precision is directly related to the density of topographical data available.
Recommended Citation
K. C. Ward and K. J. DeMarsy, "Including Topographical Effects in Slant-Range Modeling," AIAA Guidance, Navigation, and Control Conference, 2018, American Institute of Aeronautics and Astronautics, Jan 2018.
The definitive version is available at https://doi.org/10.2514/6.2018-1333
Department(s)
Mechanical and Aerospace Engineering
Publication Status
Full Access
International Standard Book Number (ISBN)
978-162410526-5
Document Type
Article - Conference proceedings
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2024 American Institute of Aeronautics and Astronautics, All rights reserved.
Publication Date
01 Jan 2018
