A ROS 2 simulation environment for UAV and UGV development using GPS-denied navigation with vision-based localization, while maintaining GPS-based geofencing for safety.

Features

GPS-Denied Navigation: Visual odometry, optical flow, and EKF sensor fusion
GPS-Based Geofencing: Safety boundaries using GPS (navigation remains GPS-free)
ArUco Marker Search: Spiral, lawnmower, and Lévy walk search algorithms
Multi-Vehicle Support: Coordinated UAV and UGV operations
ArduPilot SITL: Full flight controller simulation
Gazebo Harmonic: Modern physics simulation
ROS 2 Integration: Full ROS 2 Humble/Jazzy support

Requirements

Ubuntu 22.04 or 24.04 (WSL2 supported)
16GB RAM recommended
50GB disk space
NVIDIA GPU recommended (software rendering available)
ffmpeg, x11-utils, xdotool (for simulation recording)

Installation

git clone <repository-url> ~/sim/uav_ugv_simulation
cd ~/sim/uav_ugv_simulation
bash setup.sh

Installation takes 20-40 minutes (builds ArduPilot from source).

Quick Start

cd ~/sim/uav_ugv_simulation
source activate_venv.sh

# Spiral search (default)
bash scripts/run_autonomous.sh --search spiral

# Lawnmower search
bash scripts/run_autonomous.sh --search lawnmower

# Lévy walk search
bash scripts/run_autonomous.sh --search levy

# WSL/Software rendering
bash scripts/run_autonomous.sh --software-render --search spiral

Manual Mode (MAVProxy)

bash scripts/run_simulation.sh
# Wait for EKF initialization (~15 seconds), then:
# mode guided
# arm throttle force
# takeoff 5

ROS 2 Mode

source /opt/ros/humble/setup.bash
ros2 launch uav_ugv_simulation full_simulation.launch.py

Search Algorithms

Algorithm	Description
`spiral`	Expanding square spiral from current position
`lawnmower`	Systematic back-and-forth lane coverage
`levy`	Random walk with Lévy-distributed step lengths

All search algorithms continuously scan for ArUco markers using the downward camera during flight. Detected markers are logged with their ID, position, and distance.

Navigation uses only relative positioning:

Visual odometry from cameras
Optical flow sensors
IMU integration
Local coordinate frames (NED)

GPS is ONLY used for geofencing (safety boundaries), NOT for navigation or position control.

Speed Limits

Speed and acceleration are capped to prevent aggressive tilting in simulation. Defaults are applied automatically via configure_speed_limits() in setup_ardupilot().

Parameter	Default	Unit
`WPNAV_SPEED`	150	cm/s
`WPNAV_ACCEL`	100	cm/s²
`WPNAV_SPEED_UP`	100	cm/s
`WPNAV_SPEED_DN`	75	cm/s
`WPNAV_ACCEL_Z`	75	cm/s²
`LOIT_SPEED`	150	cm/s

Override in code:

ctrl.configure_speed_limits(wpnav_speed=200, wpnav_accel=150)

Commands

Command	Description
`bash scripts/run_autonomous.sh`	Run autonomous search
`bash scripts/run_simulation.sh`	Run manual simulation
`bash scripts/kill_simulation.sh`	Kill all processes
`bash scripts/uninstall.sh`	Uninstall ArduPilot

README.md

UAV-UGV Simulation