RF Field Build-Up inside a Manned Space Vehicle Using Novel Ray-Tracing Algorithm

Balamati Choudhury,Hema Singh,R M Jha

doi:10.1155/2013/438239

Balamati Choudhury, Hema Singh + Show 1 more

Open Access

https://doi.org/10.1155/2013/438239

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Abstract

The radio-frequency (RF) field mapping and its analysis inside a space vehicle cabin, although of immense importance, represent a complex problem due to their inherent concavity. Further hybrid surface modeling required for such concave enclosures leads to ray proliferation, thereby making the problem computationally intractable. In this paper, space vehicle is modeled as a double-curvatured general paraboloid of revolution (GPOR) frustum, whose aft section is matched to an end-capped right circular cylinder. A 3D ray-tracing package is developed which involves a uniform ray-launching scheme, an intelligent scheme for ray bunching, and an adaptive reception algorithm for obtaining ray-path details inside the concave space vehicle. Due to nonavailability of image method for concave curvatured surfaces, the proposed ray-tracing method is validated with respect to the RF field build-up inside a closed lossy cuboid using image method. The RF field build-up within the space vehicle is determined using the details of ray paths and the material parameters. The results for RF field build-up inside a metal-backed dielectric space vehicle are compared with those of highly metallic one for parallel and perpendicular polarizations. The convergence of RF field within the vehicle is analyzed with respect to the propagation time and the number of bounces a ray undergoes before reaching the receiving point.

Highlights

In the fore section of any space vehicle, astronauts work in the presence of multiple radiating sources
Ray tracing has been employed for site-specific indoor propagation models [1,2,3], and it has been shown that multiple reflections are dominant for the RF field build-up within the cavity compared to the phenomenon of diffraction [4]
As image method is not available for curved concavities such as the space vehicle, the RF field due to the rays obtained by the existing image method inside a lossy cuboid (2.70 m × 2.38 m × 2.40 m) and those obtained by the refined raytracing method developed in-house are compared

Summary

Introduction

In the fore section of any space vehicle, astronauts work in the presence of multiple radiating sources This makes the astronaut cabin of space vehicle an important indoor environment which necessitates RF field mapping. The proposed ray-tracing method is validated with respect to the RF field build-up inside a closed lossy cuboid using the image method This is because the image method is known to be valid for planar surfaces, whereas the concave curvatured surfaces like space vehicle or aircraft in-cabin have mostly nonplanar surfaces. The cumulative ray-path data up to Nth bounce including the direct ray is used for the estimation of RF field inside a space vehicle It includes the details of each ray path traversed within the space vehicle before reaching the receiving point. An empty space vehicle cabin is considered to

Surface Modeling of a Space Vehicle

Propagation inside a Space Vehicle

RF Field Build-Up inside the Space Vehicle

Results and Discussion

Conclusion