SIGMA-LM: A Hardware In Loop Simulation System for Tube Launched Loitering Munitions

This paper presents the development and validation of SIGMA-LM, a Hardware-In-the-Loop (HIL) simulation system designed for comprehensive flight phase analysis of tube-launched loitering munitions (TLLM). The system integrates open-source tools, including JSBSim for flight dynamics modeling, Pixhawk 4 (PX4) autopilot, Jetson Xavier NX mission computer, and Unreal Engine 4 (UE4) for physical scene rendering. It supports state-level and sensor-level simulation modes to accommodate varying fidelity requirements. A high-precision dynamics framework is established, encompassing plant, actuator, and sensor models, with sensor outputs incorporating noise, delays, and environmental disturbances. Experimental validation using a 10 kg-class loitering munition (SULA90) demonstrates the system's capability to replicate critical operational phases, including launch, loitering, and terminal guidance strikes. Comparative analysis with field flight data reveals high-fidelity replication for inertial and magnetic sensors, while discrepancies in GPS and barometric measurements are attributed to transient dynamics and sampling limitations. The system provides a cost-effective and reliable platform for evaluating embedded systems in high-risk scenarios, reducing dependency on physical testing.