# Drone Landing Simulation (GPS-Denied)

A GPS-denied drone landing simulation using relative sensors (IMU, altimeter, camera, landing pad detection) with **PyBullet** and **Gazebo** simulators.

## Quick Start

### Windows (Standalone - No ROS 2 Required)

```powershell
. .\activate.ps1
python standalone_simulation.py

# With moving rover
python standalone_simulation.py --pattern circular --speed 0.3
```

### Linux (Full ROS 2 Setup)

```bash
source activate.sh

# Terminal 1: Simulator
python simulation_host.py

# Terminal 2: ROS bridge
python ros_bridge.py

# Terminal 3: Controllers
python controllers.py --pattern circular --speed 0.3
```

## Architecture

```
┌─────────────────────────────────────────────────────────────────────────┐
│  STANDALONE MODE (Windows)              FULL MODE (Linux + ROS 2)       │
│  ─────────────────────────              ──────────────────────────      │
│                                                                         │
│  ┌──────────────────────┐     ┌───────────────┐    ┌───────────────┐   │
│  │standalone_simulation │     │simulation_host│◄──►│  ros_bridge   │   │
│  │  (All-in-one)        │     └───────────────┘    └───────┬───────┘   │
│  └──────────────────────┘                                  │           │
│                                                  ┌─────────▼─────────┐ │
│                                                  │   controllers.py  │ │
│                                                  │ (Drone + Rover)   │ │
│                                                  └───────────────────┘ │
└─────────────────────────────────────────────────────────────────────────┘
```

## Files

| File | Description |
|------|-------------|
| `standalone_simulation.py` | **Windows: All-in-one simulation (no ROS 2)** |
| `simulation_host.py` | PyBullet physics simulator |
| `ros_bridge.py` | UDP ↔ ROS 2 bridge |
| `gazebo_bridge.py` | Gazebo ↔ ROS 2 bridge |
| `controllers.py` | Runs drone + rover controllers |
| `drone_controller.py` | Drone landing logic (edit this) |
| `rover_controller.py` | Moving landing pad |

## Controller Options

```bash
# Standalone (Windows)
python standalone_simulation.py --pattern circular --speed 0.3

# Full mode (Linux)
python controllers.py --pattern circular --speed 0.3

Options:
  --pattern, -p   Rover pattern: stationary, linear, circular, square
  --speed, -s     Rover speed in m/s (default: 0.5)
  --amplitude, -a Rover amplitude in meters (default: 2.0)
```

## GPS-Denied Sensors

The drone has no GPS. Available sensors:

| Sensor | Data |
|--------|------|
| **IMU** | Orientation, angular velocity |
| **Altimeter** | Altitude, vertical velocity |
| **Velocity** | Estimated horizontal velocity |
| **Camera** | 320x240 downward-facing image |
| **Landing Pad** | Relative position when visible |

## Documentation

| Document | Description |
|----------|-------------|
| [Installation](docs/installation.md) | Setup for Ubuntu, macOS, Windows |
| [Architecture](docs/architecture.md) | System components and data flow |
| [Protocol](docs/protocol.md) | Sensor data formats |
| [Drone Guide](docs/drone_guide.md) | How to implement landing logic |
| [Rover Controller](docs/rover_controller.md) | Movement patterns |
| [PyBullet](docs/pybullet.md) | PyBullet-specific setup |
| [Gazebo](docs/gazebo.md) | Gazebo-specific setup (Linux only) |

## Platform Support

| Platform | Standalone | Full (ROS 2) | Gazebo |
|----------|------------|--------------|--------|
| Windows | ✅ | ⚠️ Complex | ❌ |
| Linux | ✅ | ✅ | ✅ |
| macOS | ✅ | ⚠️ Limited | ❌ |

## Getting Started

1. **Windows**: Run `python standalone_simulation.py`
2. **Linux**: Read [docs/drone_guide.md](docs/drone_guide.md)
3. Edit `drone_controller.py` to implement your algorithm
4. Test with different rover patterns