# Drone Landing Simulation (GPS-Denied)

A GPS-denied drone landing simulation using relative sensors (IMU, altimeter, camera, landing pad detection) with multiple backends:
- **PyBullet** - Lightweight physics simulation
- **Gazebo** - Full robotics simulator
- **ArduPilot SITL** - Realistic flight controller with MAVProxy

## Quick Start

### Standalone Mode (Any Platform - No ROS 2 Required)

```bash
source activate.sh  # Linux/macOS
. .\activate.ps1    # Windows

python standalone_simulation.py --pattern circular --speed 0.3
```

### PyBullet + ROS 2 (Two Terminals)

**Terminal 1 - Simulator:**
```bash
python simulation_host.py
```

**Terminal 2 - Bridge + Controllers:**
```bash
python run_bridge.py --pattern circular --speed 0.3
```

### Gazebo + ROS 2 (Two Terminals - Linux/WSL2)

**Terminal 1 - Launch Gazebo + Bridge:**
```bash
ros2 launch gazebo/launch/drone_landing.launch.py
```

**Terminal 2 - Run Controllers:**
```bash
python run_gazebo.py --pattern circular --speed 0.3
```

### ArduPilot SITL + Gazebo (Three Terminals - Realistic Flight Controller)

**Terminal 1 - Launch Gazebo with ArduPilot world:**
```bash
ros2 launch gazebo/launch/ardupilot_drone.launch.py
```

**Terminal 2 - Start ArduPilot SITL:**
```bash
cd ~/ardupilot
sim_vehicle.py -v ArduCopter -f gazebo-iris --model JSON --console
```

**Terminal 3 - Run MAVLink Bridge + Controllers:**
```bash
python run_ardupilot.py --no-sitl --pattern circular
```

## Installation

| Platform | Command |
|----------|---------|
| Ubuntu/Debian | `./setup/install_ubuntu.sh` |
| Arch Linux | `./setup/install_arch.sh` |
| macOS | `./setup/install_macos.sh` |
| Windows | `.\setup\install_windows.ps1` |

## Platform Compatibility

| Feature | Ubuntu | Arch | macOS | Windows | WSL2 |
|---------|--------|------|-------|---------|------|
| Standalone | ✅ | ✅ | ✅ | ✅ | ✅ |
| PyBullet + ROS 2 | ✅ | ⚠️ | ❌ | ❌ | ✅ |
| Gazebo + ROS 2 | ✅ | ⚠️ | ❌ | ❌ | ✅ |
| ArduPilot + Gazebo | ✅ | ⚠️ | ❌ | ❌ | ✅ |

## Files

| File | Description |
|------|-------------|
| `standalone_simulation.py` | All-in-one (no ROS 2 required) |
| `simulation_host.py` | PyBullet simulator server |
| `run_bridge.py` | PyBullet bridge + Controllers |
| `run_gazebo.py` | Gazebo bridge + Controllers |
| `run_ardupilot.py` | **ArduPilot SITL** + MAVLink bridge |
| `mavlink_bridge.py` | MAVLink ↔ ROS 2 bridge |
| `config.py` | **Configuration file** (edit to customize) |
| `drone_controller.py` | **Your landing algorithm** (edit this!) |
| `rover_controller.py` | Moving landing pad controller |

## Configuration

Edit `config.py` to customize:
- Drone/rover starting positions
- Physical properties (mass, size)
- Controller gains (Kp, Kd)
- Landing detection thresholds

## Command Line Options

```bash
# Standalone (no ROS 2)
python standalone_simulation.py --pattern circular --speed 0.3

# PyBullet + ROS 2
python run_bridge.py --pattern circular --speed 0.3 --host <SIMULATOR_IP>

# Gazebo + ROS 2  
python run_gazebo.py --pattern circular --speed 0.3

Options:
  --pattern, -p   stationary, linear, circular, square, random
  --speed, -s     Speed in m/s (default: 0.5)
  --amplitude, -a Amplitude in meters (default: 2.0)
  --host, -H      Simulator IP (default: 0.0.0.0)
```

## GPS-Denied Sensors

| Sensor | Data |
|--------|------|
| **IMU** | Orientation (roll, pitch, yaw), angular velocity |
| **Altimeter** | Altitude, vertical velocity |
| **Velocity** | Estimated horizontal velocity (x, y, z) |
| **Camera** | 320x240 downward-facing JPEG image |
| **Landing Pad** | Relative position when visible in camera FOV |

## Documentation

| Document | Description |
|----------|-------------|
| [Installation](docs/installation.md) | Platform setup guides + WSL2 |
| [Architecture](docs/architecture.md) | System components diagram |
| [Gazebo Guide](docs/gazebo.md) | Gazebo-specific instructions |
| [PyBullet Guide](docs/pybullet.md) | PyBullet-specific instructions |
| [ArduPilot Guide](docs/ardupilot.md) | **ArduPilot SITL + MAVProxy** |
| [Protocol](docs/protocol.md) | Sensor data formats |
| [Drone Guide](docs/drone_guide.md) | Landing algorithm guide |

## Network Setup (Remote Simulator)

Run simulator on one machine, controllers on another:

**Machine 1 (with display):**
```bash
python simulation_host.py  # Listens on 0.0.0.0:5555
```

**Machine 2 (headless):**
```bash
python run_bridge.py --host 192.168.1.100  # Connect to Machine 1
```