Methods of UAV navigation in difficult environmental conditions

This literature review examines contemporary approaches to UAV navigation in GPS-denied environments, focusing on four key technologies: GNSS-IMU integration, LIDAR-based navigation, geomagnetic navigation, and vision-based navigation systems. The review analyzes the principles, methodologies, and limitations of each approach. GNSS-IMU integration is discussed through the lens of different coupling architectures, highlighting their vulnerabilities to interference and spoofing. LIDAR-based navigation is examined with emphasis on point cloud processing and its limitations in various environmental conditions. The review explores recent developments in geomagnetic navigation, including military applications and machine learning integration, while acknowledging challenges in calibration and data resolution. Vision-based navigation is analyzed through the evolution of SLAM and visual odometry techniques, with particular attention to deep learning applications and visual terrain relative navigation. The review concludes that each technology has distinct advantages and limitations, suggesting that robust UAV navigation likely requires a multi-sensor fusion approach adapted to specific operational requirements.