# DroneController Guide

Implement your GPS-denied landing algorithm.

## Quick Start

1. Edit `drone_controller.py`
2. Find `calculate_landing_maneuver()`
3. Implement your algorithm
4. Test with any simulation mode

## Function to Implement

```python
def calculate_landing_maneuver(self, telemetry, rover_telemetry):
    # Your logic here
    return (thrust, pitch, roll, yaw)
```

## Sensors (GPS-Denied)

```python
# Altitude
altitude = telemetry['altimeter']['altitude']
vertical_vel = telemetry['altimeter']['vertical_velocity']

# Velocity
vel_x = telemetry['velocity']['x']
vel_y = telemetry['velocity']['y']

# Landing Pad (may be None!)
landing_pad = telemetry.get('landing_pad')
if landing_pad:
    relative_x = landing_pad['relative_x']
    relative_y = landing_pad['relative_y']
```

## Control Output

| Value | Range | Effect |
|-------|-------|--------|
| thrust | ±1.0 | Up/down (positive = up) |
| pitch | ±0.5 | Forward/back |
| roll | ±0.5 | Left/right |
| yaw | ±0.5 | Rotation |

Note: In ArduPilot mode, these are scaled to velocities:
- Thrust → Z velocity
- Pitch/Roll → X/Y velocity

## Example Algorithm (PD Control)

```python
def calculate_landing_maneuver(self, telemetry, rover_telemetry):
    alt = telemetry.get('altimeter', {})
    altitude = alt.get('altitude', 5.0)
    vert_vel = alt.get('vertical_velocity', 0.0)
    
    # Altitude PD control
    thrust = 0.5 * (target_alt - altitude) - 0.3 * vert_vel
    
    # Horizontal control
    pad = telemetry.get('landing_pad')
    if pad:
        pitch = 0.3 * pad['relative_x']
        roll = 0.3 * pad['relative_y']
    else:
        # Hover
        pitch = 0
        roll = 0
    
    return (thrust, pitch, roll, 0.0)
```