docs: Improve quick start, ArduPilot setup, and troubleshooting, and add GPS mode option.

README.md

@@ -1,6 +1,6 @@
 # RDC Simulation
 
-GPS-denied drone landing simulation using ArduPilot and Gazebo.
+**GPS-Denied Drone Landing Simulation** using ArduPilot and Gazebo.
 
 ## Quick Start
 
@@ -23,25 +23,23 @@ cd RDC_Simulation
 source ~/.bashrc
 ```
 
-### Run the Simulation
+### Run the Simulation (3 Terminals)
 
-You need **3 terminals**:
-
-**Terminal 1 - Gazebo:**
+**Terminal 1 - Start Gazebo FIRST:**
 ```bash
 cd ~/RDC_Simulation
 ./scripts/run_ardupilot_sim.sh runway
-# Wait until the drone appears in Gazebo
+# WAIT until you see the drone in Gazebo!
 ```
 
-**Terminal 2 - SITL:**
+**Terminal 2 - Start ArduCopter SITL:**
 ```bash
 source ~/venv-ardupilot/bin/activate
 sim_vehicle.py -v ArduCopter -f gazebo-iris --model JSON --console
-# Wait for "Waiting for connection" then telemetry
+# Wait for "JSON received:" messages (shows Gazebo is connected)
 ```
 
-**Terminal 3 - Controller:**
+**Terminal 3 - Run Controller:**
 ```bash
 source ~/venv-ardupilot/bin/activate
 cd ~/RDC_Simulation
@@ -62,6 +60,9 @@ python scripts/run_ardupilot.py --pattern hover
 
 # Custom altitude
 python scripts/run_ardupilot.py --pattern square --altitude 10
+
+# Use GPS mode instead of GPS-denied
+python scripts/run_ardupilot.py --pattern square --gps
 ```
 
 ## Project Structure
@@ -71,13 +72,13 @@ RDC_Simulation/
 ├── scripts/
 │   ├── run_ardupilot_sim.sh      # Launch Gazebo
 │   ├── run_ardupilot_controller.sh # Launch SITL + Controller
-│   └── run_ardupilot.py          # Flight controller
+│   └── run_ardupilot.py          # Flight controller entry point
 ├── src/
-│   ├── drone_controller.py       # Simple drone controller
+│   ├── drone_controller.py       # Main drone controller class
 │   ├── rover_controller.py       # Moving landing pad (ROS 2)
 │   └── camera_viewer.py          # Camera viewer (ROS 2)
 ├── setup/
-│   ├── install_ubuntu.sh         # Ubuntu installer
+│   ├── install_ubuntu.sh         # Ubuntu/WSL installer
 │   ├── install_ardupilot.sh      # ArduPilot installer
 │   └── install_arch.sh           # Arch Linux installer
 ├── gazebo/
@@ -92,29 +93,40 @@ RDC_Simulation/
 Gazebo isn't sending data to SITL.
 - **Fix**: Start Gazebo FIRST, wait for it to fully load, THEN start SITL.
 
-### "empy not found"
-Wrong Python environment.
-- **Fix**: `source ~/venv-ardupilot/bin/activate`
+### "empy not found" or wrong Python
+Wrong virtual environment.
+```bash
+source ~/venv-ardupilot/bin/activate
+pip install empy==3.3.4
+```
 
 ### "sim_vehicle.py not found"
 ArduPilot tools not in PATH.
-- **Fix**: `source ~/.ardupilot_env`
+```bash
+source ~/.ardupilot_env
+```
 
-### Can't arm
-The drone won't arm or takeoff.
-- **Fix**: Make sure you're in GUIDED mode and Gazebo is running.
-- Check console for pre-arm errors.
+### Drone won't arm
+- Make sure SITL is in STABILIZE or GUIDED mode
+- Check for pre-arm errors in MAVProxy console
+- Try in MAVProxy: `arm throttle force`
 
-### Gazebo is slow
-- Try a lighter world: `./scripts/run_ardupilot_sim.sh runway`
-- Check GPU: `glxinfo | grep "OpenGL renderer"`
+### Wrong vehicle type (ArduPlane instead of ArduCopter)
+You see modes like FBWA, FBWB, QSTABILIZE.
+```bash
+# Kill old processes
+pkill -9 -f sim_vehicle
+
+# Start with explicit ArduCopter
+sim_vehicle.py -v ArduCopter -f gazebo-iris --model JSON --console --wipe-eeprom
+```
 
 ## Documentation
 
 - [Installation Guide](docs/installation.md)
 - [ArduPilot Guide](docs/ardupilot.md)
+- [Drone Controller Guide](docs/drone_guide.md)
 - [Architecture](docs/architecture.md)
-- [Gazebo Worlds](docs/gazebo_worlds.md)
 
 ## License