# Research on Radio Altimetry in Urban Environments Based on Electromagnetic Simulation Echo Modeling Technology

## TL;DR

This study improves radio altimetry accuracy in cities by simulating electromagnetic wave behavior around buildings.

## Contribution

A novel integration of radar altimetry simulation with large-scale urban electromagnetic models is proposed.

## Key findings

- Increased building density and height worsen radar altimetry errors.
- Reduced elevation angles during altimetry increase ranging errors.
- SBR and IFFT methods enable detailed echo signal simulation in urban settings.

## Abstract

As the low-altitude economy develops rapidly, precise radar altimetry is crucial for ensuring the safety and reliability of drone flights. In the context of urban radio detection, the presence of numerous buildings and ground surfaces gives rise to electromagnetic wave multipath propagation. This objective factor gives rise to errors in radar altimetry. Existing channel models often lack the intricate details required to accurately quantify multipath error mechanisms in kilometer-scale complex electromagnetic environments. Therefore, there is an urgent need for a high-fidelity simulation framework. The present study has put forward a pioneering approach to radio altimetry simulation and accuracy assessment in intricate urban environments. The objective of this study is to investigate the impact of multipath propagation on radar altimetry precision. The present study has proposed a novel integration of radar altimetry simulation with kilometre-scale urban electromagnetic simulation models. The simulation of echo signals has been achieved through the utilization of the shooting and bouncing rays (SBR) method and inverse fast Fourier transform (IFFT). A comparative analysis has been conducted based on ranging results from radar systems for different urban models, thereby enabling a mechanism analysis of factors affecting radar altimetry. The study has demonstrated that increased building density and height, along with reduced elevation angles during altimetry, exacerbate ranging errors.