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1.6 First Autonomous Mission

What You'll Learn

Execute your first complete autonomous drone mission:

  • Understand waypoint mission structure
  • Create mission file in proper format
  • Load mission into SITL
  • Execute AUTO mode flight
  • Monitor mission progress
  • Analyze flight logs
  • Complete Phase 1 successfully

Time: 60-90 minutes

Prerequisites

Before starting, you must have completed:

What is a Mission?

Mission = Pre-planned list of commands the drone executes autonomously

Mission commands include:

  • Takeoff to altitude
  • Fly to waypoint (latitude, longitude, altitude)
  • Perform action (take photo, wait, change speed)
  • Return to launch
  • Land

AUTO mode: Flight mode that executes loaded mission automatically.

Why missions matter:

  • Real-world applications (surveying, delivery, inspection)
  • Repeatable flights
  • Complex patterns without manual control
  • Foundation for advanced autonomy

Mission File Format

QGroundControl Waypoint Format

ArduPilot uses QGC WPL 110 format (QGroundControl Waypoint List).

File structure: 

QGC WPL 110
0  1  0  16  0  0  0  0  LAT  LON  ALT  1
1  0  3  22  0.00  0.00  0.00  0.00  0.0  0.0  10.0  1
2  0  3  16  0.00  0.00  0.00  0.00  -35.36  149.16  20.0  1
3  0  3  16  0.00  0.00  0.00  0.00  -35.37  149.17  20.0  1
4  0  3  16  0.00  0.00  0.00  0.00  -35.36  149.17  20.0  1
5  0  3  21  0.00  0.00  0.00  0.00  0.0  0.0  0.0  1

Header line: QGC WPL 110

Each line (waypoint) has 12 columns:

Column Name Description Example
1 Index Waypoint number 0, 1, 2, 3...
2 Current Home position (1) or waypoint (0) 1 for home, 0 for others
3 Frame Coordinate system (3 = relative altitude) 3
4 Command MAVLink command ID 16=WAYPOINT, 22=TAKEOFF, 21=RTL
5-8 Params Command-specific parameters Usually 0
9 Latitude Latitude in decimal degrees -35.363261
10 Longitude Longitude in decimal degrees 149.165237
11 Altitude Altitude in meters (relative to home) 10.0, 20.0
12 Autocontinue Auto-continue to next waypoint (1=yes) 1
Command ID Name Purpose
16 NAV_WAYPOINT Fly to waypoint and hold
22 NAV_TAKEOFF Takeoff to altitude
20 NAV_LAND Land at location
21 NAV_RETURN_TO_LAUNCH Return and land at home
93 NAV_DELAY Wait at waypoint (seconds)

Full list: https://mavlink.io/en/messages/common.html

Create Your First Mission

Mission Plan

Let's create a simple square pattern:

  1. Takeoff to 10m
  2. Fly North 30m at 20m altitude
  3. Fly East 30m at 20m altitude
  4. Fly South 30m (back toward start) at 20m altitude
  5. Fly West 30m (return to start position) at 20m altitude
  6. Return to Launch (RTL at 15m, then land)

Flight path:

Start/Land
    ↓
    1 (Takeoff 10m)
    ↓
    2 (North 30m, alt 20m)
    ↓
    3 (East 30m, alt 20m)
    ↓
    4 (South 30m, alt 20m)
    ↓
    5 (West 30m, alt 20m)
    ↓
    6 (RTL - Return home)
Square Mission Waypoints - Top Down View

Create Mission File

The missions directory was created in Section 1.2. Create the mission file:

nano ~/simtofly_ws/missions/square_mission.txt

Mission File Created

Mission File Content

Paste this exactly: 

QGC WPL 110
0   1   0   16  0   0   0   0   -35.363261  149.165237  584 1
1   0   3   22  0.00000000  0.00000000  0.00000000  0.00000000  0.00000000  0.00000000  10.0000000  1
2   0   3   16  0.00000000  0.00000000  0.00000000  0.00000000  -35.362991  149.165237  20.0000000  1
3   0   3   16  0.00000000  0.00000000  0.00000000  0.00000000  -35.362991  149.165507  20.0000000  1
4   0   3   16  0.00000000  0.00000000  0.00000000  0.00000000  -35.363261  149.165507  20.0000000  1
5   0   3   16  0.00000000  0.00000000  0.00000000  0.00000000  -35.363261  149.165237  20.0000000  1
6   0   3   21  0.00000000  0.00000000  0.00000000  0.00000000  0.00000000  0.00000000  0.0000000   1

Save and exit: Ctrl+X, then Y, then Enter

Understanding the Mission File

Line 0 (Home position): 

0  1  0  16  0  0  0  0  -35.363261  149.165237  584  1

  • Index 0, Current=1 (home), Command 16 (waypoint)
  • Lat/Lon: Default SITL location (Australia)
  • Alt: 584m MSL (mean sea level)

Line 1 (Takeoff): 

1  0  3  22  0  0  0  0  0  0  10.0  1

  • Command 22 (TAKEOFF)
  • Altitude: 10m (relative to home)

Lines 2-5 (Waypoints): 

2  0  3  16  0  0  0  0  -35.362991  149.165237  20.0  1

  • Command 16 (WAYPOINT)
  • Each corner of square
  • Altitude: 20m (relative)

Line 6 (Return to Launch): 

6  0  3  21  0  0  0  0  0  0  0  1

  • Command 21 (RTL)
  • Climbs to 15m (default RTL altitude)
  • Returns to home and lands

Mission Execution Flow

Before executing, understand the state transitions:

Mission Execution State Flow

Execute Mission in SITL

Video Demonstration

Watch the complete mission execution in SITL:

SITL Mission Demo

Complete autonomous square pattern mission with 2D map visualization

Launch SITL

Start SITL with map and console:

sim_vehicle.py -v ArduCopter --map --console

Note: We can run sim_vehicle.py from any directory because we added it to PATH in Section 1.3.

Wait for: STABILIZE> prompt and map window to open.

Load Mission File

At MAVProxy prompt:

wp load /home/YOUR_USERNAME/simtofly_ws/missions/square_mission.txt

Important: Replace YOUR_USERNAME with your actual username.

Full Absolute Path Required

MAVProxy does not expand ~ or $HOME variables. You must use the complete path.

To find your username: 

echo $USER

Expected output: 

Loaded 7 waypoints from /home/YOUR_USERNAME/simtofly_ws/missions/square_mission.txt

Mission Load Success

✅ Success: Mission loaded (7 items: home + 6 commands)

Note: MAVProxy requires full absolute path. Using ~ or $HOME will not work.

Verify Mission Loaded

wp list

Expected output: 

0  HOME(-35.363261, 149.165237, 584.00)
1  TAKEOFF(0.000000, 0.000000, 10.00)
2  WAYPOINT(-35.362991, 149.165237, 20.00)
3  WAYPOINT(-35.362991, 149.165507, 20.00)
4  WAYPOINT(-35.363261, 149.165507, 20.00)
5  WAYPOINT(-35.363261, 149.165237, 20.00)
6  RTL(0.000000, 0.000000, 0.00)

Mission List Output

✅ Success: All waypoints listed correctly

Map window: Should show waypoint markers connected by lines.

Execute Mission

Command sequence:

mode GUIDED
arm throttle
takeoff 10
mode AUTO

What happens:

  1. Switch to GUIDED mode
  2. Motors spin up (armed)
  3. Drone takes off to 10m
  4. Switch to AUTO mode
  5. Mission executes automatically:
  6. Climbs to 20m
  7. Flies to each waypoint in sequence
  8. Returns to start position (RTL)
  9. Descends and lands
  10. Automatically disarms

This takes: 2-3 minutes total.

Why GUIDED first? Starting in GUIDED mode and taking off manually before AUTO ensures all systems are working and provides smoother transition to autonomous flight.

Monitor Mission Progress

Watch console window: - Current waypoint number - Altitude climbing/descending - Distance to next waypoint

Watch map window: - Drone icon moving - Following waypoint path - Position updating in real-time

MAVProxy prompt shows: 

AUTO> WP: 2
AUTO> WP: 3
AUTO> WP: 4
...

✅ Success: Mission completes, drone lands and disarms

Execute Mission in Gazebo

Video Demonstration

Watch the mission with realistic 3D visualization:

Gazebo Mission Demo

Same mission with Gazebo Harmonic 3D physics and visualization

Launch Gazebo

Terminal 1: 

gz sim -v4 -r iris_runway.sdf

Wait for: Gazebo window and drone to load.

Launch SITL

Terminal 2: 

sim_vehicle.py -v ArduCopter -f gazebo-iris --model JSON --map --console

Wait for: Connection established, STABILIZE> prompt.

Load and Execute Mission

In Terminal 2 (SITL prompt):

wp load /home/YOUR_USERNAME/simtofly_ws/missions/square_mission.txt
wp list
mode GUIDED
arm throttle
takeoff 10
mode AUTO

Watch in Gazebo:

  • Propellers spin
  • Drone lifts off
  • Flies square pattern in 3D
  • Returns and lands
  • Realistic physics simulation

Much more impressive with 3D visualization!

✅ Success: Complete autonomous mission in Gazebo

Understanding Mission Behavior

Mission States

Pre-flight:

  • Mission loaded but not executing
  • Can review with wp list
  • Can clear with wp clear

During mission (AUTO mode):

  • Executing waypoints sequentially
  • Current waypoint shown in console
  • Can pause: mode LOITER (requires rc 3 1500 first)
  • Can resume: mode AUTO (continues from next waypoint)

Mission complete:

  • Returns to launch via RTL
  • Lands at home position
  • Automatically disarms
  • Mode stays AUTO

RTL Behavior

When RTL command executes (waypoint 6 or manual mode RTL):

  1. Drone climbs to RTL altitude (15m default) if below
  2. Flies directly to home position
  3. Descends at controlled rate
  4. Lands at home
  5. Automatically disarms

RTL altitude parameter: RTL_ALT (default 1500 = 15 meters)

Useful for: Mission completion or emergency return

Pausing Mission Mid-Flight

To pause and hold position:

rc 3 1500        # Set throttle first (prevents altitude loss)
mode LOITER      # Holds current GPS position

To resume mission: 

mode AUTO        # Continues from next waypoint

Emergency abort: 

mode RTL         # Returns to home immediately

Alternative Mission Execution Method

Advanced: Direct AUTO Mode

For experienced users, direct AUTO mode from ground:

wp load /home/YOUR_USERNAME/simtofly_ws/missions/square_mission.txt
mode LOITER
rc 3 1500
arm throttle
mode AUTO

This method:

  • Uses mission's TAKEOFF command directly
  • Requires throttle setting to prevent failsafe
  • More complex but demonstrates proper AUTO mode usage

Beginners should use GUIDED method shown above.

Create Custom Mission

Using Your Location

Find your coordinates:

  • Google Maps: Right-click location → Click coordinates to copy
  • Format: Latitude, Longitude (e.g., 37.7749, -122.4194)

Mission Template

Create ~/simtofly_ws/missions/custom_mission.txt:

QGC WPL 110
0   1   0   16  0   0   0   0   YOUR_LAT    YOUR_LON    YOUR_ALT    1
1   0   3   22  0   0   0   0   0   0   10.0    1
2   0   3   16  0   0   0   0   WAYPOINT1_LAT   WAYPOINT1_LON   15.0    1
3   0   3   16  0   0   0   0   WAYPOINT2_LAT   WAYPOINT2_LON   15.0    1
4   0   3   21  0   0   0   0   0   0   0   1

Replace:

  • YOUR_LAT, YOUR_LON — Your home position
  • YOUR_ALT — Your altitude MSL (check Google Earth)
  • WAYPOINT1_LAT, WAYPOINT1_LON — First waypoint
  • WAYPOINT2_LAT, WAYPOINT2_LON — Second waypoint

Coordinate Math (Approximate)

At equator (rough estimates):

  • 1° latitude ≈ 111 km
  • 1° longitude ≈ 111 km

For small distances:

  • 0.0001° ≈ 11 meters
  • 0.001° ≈ 111 meters

Example: Move 50m North from start: 

Original Lat: -35.363261
Add 0.00045: -35.362811  (≈50m North)

Better tool: Use mission planner software or online calculators.

Analyzing Flight Logs

Where Logs Are Saved

SITL saves logs automatically:

cd ~/simtofly_ws/ardupilot/ArduCopter/logs
ls -lt

Expected output: 

00000001.BIN
00000002.BIN
...

Latest log: Highest number.

Advanced: Log Analysis (Optional)

Online tool (Recommended for beginners):

Upload logs to: https://plot.ardupilot.org/

Features:

  • No installation needed
  • Visual graphs of flight data
  • Analyze altitude, speed, position
  • Compare multiple flights
  • Share analysis with others

To upload:

  1. Find latest .BIN file in logs directory
  2. Go to https://plot.ardupilot.org/
  3. Upload the file
  4. Explore interactive graphs

Command-Line Log Viewing

View log summary: 

cd ~/simtofly_ws/ardupilot/ArduCopter/logs
mavlogdump.py 00000001.BIN | less

Extract mission data: 

mavlogdump.py 00000001.BIN | grep "MISSION"

Extract mode changes: 

mavlogdump.py 00000001.BIN | grep "MODE"

Extract GPS positions: 

mavlogdump.py 00000001.BIN | grep "GPS"

Mission Best Practices

Safety Guidelines

Always:

  • Test missions in SITL before real hardware
  • Include takeoff command as first action
  • Include RTL or LAND as last command
  • Keep waypoints within safe distance
  • Check altitude limits (not too high)

Never:

  • Skip home position (line 0)
  • Use absolute altitude without understanding MSL
  • Create waypoints too close together (minimum ~5m)
  • Forget autocontinue flag (missions won't progress)

Mission Design Tips

Start simple:

  • 3-5 waypoints maximum
  • Single altitude throughout
  • Familiar area

Progress to complex:

  • Multiple altitudes
  • Actions at waypoints (delay, change speed)
  • Survey patterns (grid, spiral)

Test incrementally:

  • Fly each waypoint manually first
  • Then convert to mission
  • Test in SITL
  • Finally test on real hardware (Phase 4)

Verification Checklist

Before moving to Phase 2, verify you can:

  • Launch SITL from any directory (PATH set)
  • Create mission file with correct format
  • Load mission using full path
  • Verify mission with wp list
  • Execute mission in SITL (GUIDED → AUTO)
  • Execute mission in Gazebo with 3D visualization
  • Monitor mission progress via map and console
  • Understand RTL behavior
  • Pause and resume mission if needed
  • Find and view flight logs
  • Create custom mission files

All checked? Congratulations! Phase 1 complete!

What You Accomplished in Phase 1

Simulation Environment:

  • ✅ Set up complete Ubuntu development environment
  • ✅ Installed ArduPilot SITL simulator
  • ✅ Configured Gazebo Harmonic 3D simulation
  • ✅ Built ArduPilot Gazebo plugin from source

Drone Control:

  • ✅ Mastered MAVProxy command-line control
  • ✅ Understood flight modes and their purposes
  • ✅ Performed manual flights (arm, takeoff, navigate, land)
  • ✅ Monitored telemetry data in real-time

Autonomous Flight:

  • ✅ Created waypoint mission files
  • ✅ Loaded and executed autonomous missions
  • ✅ Completed full square pattern mission in SITL and Gazebo
  • ✅ Analyzed flight logs

Foundation Built:

  • ✅ Safe testing environment (no hardware risk)
  • ✅ Understanding of ArduPilot fundamentals
  • ✅ Ready for ROS2 integration (Phase 2)

What's Next: Phase 2 - ROS2 Integration

Coming in Phase 2:

  • Install ROS2 Humble
  • Setup MAVROS (MAVLink ↔ ROS2 bridge)
  • Create ROS2 nodes for drone control
  • Subscribe to telemetry topics
  • Publish control commands
  • Execute missions via ROS2
  • Visualize data in RViz

Why ROS2?

  • More flexible than MAVProxy
  • Industry-standard robotics framework
  • Integrate sensors (cameras, lidar)
  • Advanced autonomy algorithms
  • Multi-robot systems

Common Questions

Q: Can I create missions with a GUI instead of text files?

A: Yes! Use these tools:

  • Mission Planner (Windows, most popular)
  • QGroundControl (Cross-platform)
  • APM Planner 2 (Cross-platform)

They all export to same .txt format we use here.

Q: What's the maximum mission size?

A: ArduPilot supports up to 700+ waypoints, but practical limits:

  • SITL: Unlimited (memory constrained)
  • Real hardware: ~100-200 waypoints typical
  • Depends on flight controller memory

Q: Why use GUIDED takeoff before AUTO mode?

A: Starting in GUIDED mode provides:

  • Visual confirmation systems are working
  • Smoother transition to AUTO mode
  • Better for beginners learning the workflow
  • Advanced users can use direct AUTO mode

Q: Why does my mission skip waypoints?

Possible causes:

  1. Autocontinue flag = 0 (should be 1)
  2. Waypoint acceptance radius too large
  3. Mission file syntax error

Check: wp list shows all waypoints correctly.

Q: How do I add camera trigger at waypoint?

A: Use DO_SET_CAM_TRIGG_DIST command (ID 206): 

3  0  3  206  10  0  0  0  0  0  0  1
Triggers camera every 10 meters.

More on this: ArduPilot camera trigger documentation.

Q: What's the difference between LAND and RTL?

A:

  • LAND (20): Lands at current position immediately
  • RTL (21): Returns to home position, then lands
  • RTL climbs to 15m before returning (safety feature)

Troubleshooting

Mission won't load - "Failed to load waypoints"

Cause: File format error or path issue

Solution:

  1. Use full absolute path (not ~ or $HOME)
  2. Check header line: QGC WPL 110 (exact text)
  3. Verify 12 columns per line (tab or space separated)
  4. No extra blank lines
  5. Home position (line 0) has Current=1

Mission loads but drone doesn't move

Cause: Not in AUTO mode or not armed properly

Solution: 

mode GUIDED
arm throttle
takeoff 10
mode AUTO
In this exact order.

Drone flies to wrong location

Cause: Incorrect coordinates in mission file

Solution:

  • Verify latitude/longitude are in decimal degrees (not DMS)
  • Check sign (negative for South/West)
  • Verify altitude is relative (Frame=3), not absolute

Mission starts but immediately disarms

Cause: Throttle failsafe or starting directly in AUTO

Solution: Use GUIDED takeoff method: 

mode GUIDED
arm throttle
takeoff 10
mode AUTO

Drone hovers at waypoint and doesn't continue

Cause: Autocontinue flag = 0

Solution: - Last column of each line should be 1 - Change 0 to 1 in mission file - Reload mission

"No GPS lock" in SITL

Cause: Rare in SITL, GPS initializes instantly

Solution:

  • Wait 5 seconds after SITL launch
  • Check console shows GPS: 3D Fix
  • Restart SITL if issue persists

Cannot load mission file - "No such file or directory"

Cause: MAVProxy doesn't expand ~ or $HOME

Solution: Use full absolute path: 

wp load /home/YOUR_USERNAME/simtofly_ws/missions/square_mission.txt

Find your username with: echo $USER

Additional Resources

ArduPilot Documentation:

  • Mission Commands: https://ardupilot.org/copter/docs/common-mavlink-mission-command-messages-mav_cmd.html
  • Mission Planning: https://ardupilot.org/copter/docs/common-mission-planning.html
  • AUTO Mode: https://ardupilot.org/copter/docs/auto-mode.html

MAVLink Protocol:

  • Command Reference: https://mavlink.io/en/messages/common.html
  • Mission Protocol: https://mavlink.io/en/services/mission.html

Tools:

  • QGroundControl: http://qgroundcontrol.com/
  • Mission Planner: https://ardupilot.org/planner/
  • MAVProxy Documentation: https://ardupilot.org/mavproxy/
  • Log Analysis: https://plot.ardupilot.org/

Congratulations on Completing Phase 1!

You've built a solid foundation in drone simulation and autonomous flight. You now understand:

  • ArduPilot SITL simulator
  • Gazebo 3D visualization
  • MAVProxy control
  • Waypoint missions
  • Autonomous flight execution

You're ready for Phase 2: ROS2 Integration

Take a break, review what you've learned, and when ready, continue your journey!

Share Your Success

Completed Phase 1? We'd love to hear about it!

  • Star the repository: https://github.com/simtofly/simtofly-guide
  • Share your experience in Discussions
  • Help others in Issues section
  • Tweet with #SimToFly

Your feedback helps improve this tutorial for everyone!

← Back: 1.5 Gazebo Simulation | Next: Phase 2 Overview →

Phase 1 Complete!
You've mastered simulation. Now let's integrate ROS2.

Continue to Phase 2 →