'raytrace' function for LEO satellites (2024)

To address the issue of insufficient multipath rays when using the 'raytrace' function for a LEO satellite transmitter at high altitudes, you need to consider a few aspects related to ray tracing and the parameters used. Here are some strategies and potential solutions:

1. Increase Ray Density Beyond Default Limits:

• The limitation you're encountering with the pm.AngularSeparation parameter suggests that the default minimum of 0.05 degrees is not fine enough for your application at 400 km altitude. One way to handle this is to modify the underlying code of the 'raytrace' function (if possible) to allow for a smaller angular separation. This might involve changing the limits within the function's source code or configuration files if you have access to them.

2. Use Subdivision Techniques:

• Another approach is to implement a ray subdivision technique where rays are further subdivided during the simulation based on certain criteria, such as distance from obstacles or areas of interest. This can help in generating more rays in critical regions without overwhelming the entire simulation with excessive rays.

3. Increase the Number of Launched Rays:

• If the raytrace function allows for specifying the total number of rays to be launched, increase this number significantly. This may help in covering more paths, especially in dense urban environments where reflections and diffractions are more common.

4. Optimize Scene Geometry:

• Ensure that the scene geometry (buildings, obstacles, etc.) is detailed enough to create opportunities for multipath reflections. Sometimes, insufficient detail in the urban environment model can lead to fewer interactions of rays with the scene.

5. Use Hybrid or Alternative Methods:

• Consider hybrid methods that combine deterministic ray tracing with statistical models for multipath propagation. Techniques like the image method for reflection calculation, combined with stochastic models for diffraction and scattering, might offer a more comprehensive multipath profile.

6. Parameter Sensitivity Analysis:

• Conduct a sensitivity analysis on other parameters that might influence the ray tracing results. Parameters like the reflection and diffraction coefficients, the resolution of the urban scenario, and the environment's electromagnetic properties can significantly impact the multipath characteristics.

7. Custom Ray Launcher:

• If the existing function is too restrictive, develop a custom ray launcher that more densely samples the angular space. This custom launcher can be integrated with your existing simulation framework to ensure a higher density of rays, particularly for longer distances.

8. Post-Processing Multipath Analysis:

• After running the raytrace function, perform a post-processing step where additional potential paths are generated based on the initial results. This step can include generating new rays from the endpoints of the initially traced rays to explore further interactions.

To resolve the issue with raytrace and ensure sufficient multipath propagation for a LEO satellite at 400 km altitude, you may need to either adjust the parameters beyond their default limits or employ additional techniques to enhance ray density and interaction modeling. If the source code or configuration settings are accessible, modifying them to allow finer angular separations would be a direct approach. Otherwise, implementing custom solutions or hybrid methods might be necessary to achieve the desired multipath profile