# Usage Guide

How to run and control the simulation.

## Starting the Simulation

```bash
cd ~/simulation
source activate_venv.sh
bash scripts/run_simulation.sh
```

This launches:
1. Gazebo with the drone model
2. ArduPilot SITL (flight controller)
3. MAVProxy console (for commands)

## Simulation Options

```bash
# Default (iris_runway world)
bash scripts/run_simulation.sh

# Specific world
bash scripts/run_simulation.sh --world iris_runway

# Rover instead of copter
bash scripts/run_simulation.sh --vehicle Rover

# Software rendering (for WSL or no GPU)
bash scripts/run_simulation.sh --software-render

# Show available options
bash scripts/run_simulation.sh --help
```

## Controlling the UAV

### MAVProxy Console

The simulation opens a MAVProxy console. Commands:

```
mode guided      # Switch to GUIDED mode (required for commands)
arm throttle     # Arm motors
takeoff 5        # Takeoff to 5 meters altitude

# Fly to position (North, East, Down in meters)
guided 10 0 -5   # 10m north, 0m east, 5m altitude
guided 10 10 -5  # 10m north, 10m east, 5m altitude
guided 0 0 -5    # Return to origin at 5m altitude

rtl              # Return to launch
land             # Land at current position
disarm           # Disarm motors (after landing)
```

### ROS 2 Interface

If MAVROS is running, control via ROS 2:

```bash
# Arm
ros2 service call /mavros/cmd/arming mavros_msgs/srv/CommandBool "{value: true}"

# Set GUIDED mode
ros2 service call /mavros/set_mode mavros_msgs/srv/SetMode "{custom_mode: 'GUIDED'}"

# Takeoff
ros2 service call /mavros/cmd/takeoff mavros_msgs/srv/CommandTOL "{altitude: 5}"

# Fly to position (local frame, meters)
ros2 topic pub /mavros/setpoint_position/local geometry_msgs/PoseStamped \
  "{header: {frame_id: 'map'}, pose: {position: {x: 10, y: 5, z: 5}}}"

# Land
ros2 service call /mavros/cmd/land mavros_msgs/srv/CommandTOL "{}"
```

### Monitoring

```bash
# List topics
ros2 topic list

# View position
ros2 topic echo /mavros/local_position/pose

# View velocity
ros2 topic echo /mavros/local_position/velocity_local

# View IMU
ros2 topic echo /mavros/imu/data
```

## Flight Modes

| Mode | Description |
|------|-------------|
| STABILIZE | Manual control with attitude stabilization |
| ALT_HOLD | Maintain altitude, manual position |
| LOITER | Hold position and altitude |
| GUIDED | Accept position commands |
| AUTO | Follow pre-planned mission |
| RTL | Return to launch point |
| LAND | Controlled descent and landing |

## Stopping the Simulation

Press `Ctrl+C` in the terminal running the simulation.

Or run:
```bash
bash scripts/kill_simulation.sh
```

## Camera Topics

The UAV has two cameras:

```bash
# Forward camera (visual odometry)
ros2 topic echo /uav/camera/forward/image_raw

# Downward camera (optical flow)
ros2 topic echo /uav/camera/downward/image_raw
```

## GPS-Denied Navigation

All position commands use local coordinates (meters from takeoff point):
- X: North
- Y: East  
- Z: Up (or Down for NED frame)

GPS is only used for geofencing boundaries, not for navigation.