# ArduPilot GPS-Denied Simulation

Realistic flight controller simulation without GPS.

## Quick Start (2 Terminals)

**Terminal 1:**
```bash
./scripts/run_ardupilot_sim.sh runway
```

**Terminal 2:**
```bash
sim_vehicle.py -v ArduCopter -f gazebo-iris --model JSON --console

# GPS-denied mode:
param set ARMING_CHECK 0
mode stabilize
arm throttle force
```

## Installation

```bash
./setup/install_ardupilot.sh
source ~/.bashrc
```

## World Options

```bash
./scripts/run_ardupilot_sim.sh runway     # Iris on runway (default)
./scripts/run_ardupilot_sim.sh warehouse  # Iris in warehouse
./scripts/run_ardupilot_sim.sh zephyr     # Zephyr plane
./scripts/run_ardupilot_sim.sh gimbal     # Gimbal test
./scripts/run_ardupilot_sim.sh parachute  # Parachute test
```

## GPS-Denied Configuration

In MAVProxy console:

```bash
param set ARMING_CHECK 0   # Disable pre-arm checks
mode stabilize             # Manual with stabilization
arm throttle force         # Force arm
```

## GPU Support

Auto-detects: NVIDIA > Intel > AMD > Software

Check your GPU:
```bash
glxinfo | grep "OpenGL renderer"
```

## MAVProxy Commands

```bash
mode stabilize     # Manual mode
mode alt_hold      # Altitude hold
arm throttle force # Arm motors
takeoff 5          # Takeoff 5m
mode land          # Land
```

## Troubleshooting

### "No JSON sensor message"

Gazebo isn't sending data to SITL. Check:
1. Start Gazebo FIRST, then SITL
2. Plugin path is set:
```bash
echo $GZ_SIM_SYSTEM_PLUGIN_PATH | grep ardupilot
```

### Simulation laggy

Check GPU is being used (not software):
```bash
glxinfo | grep "OpenGL renderer"
# Should NOT show "llvmpipe"
```

### Can't arm

```bash
param set ARMING_CHECK 0
arm throttle force
```