let’s now do the same circle mission upload using a Python script with MAVROS.

This script will:

1. Clear any existing mission
2. Generate a set of waypoints arranged in a circle (polygon approximation)
3. Upload them to PX4
4. Arm the vehicle
5. Switch to AUTO.MISSION

Waypoint msg Structure

🔹 Example: mission_circle.py

#!/usr/bin/env python3
import math
import rclpy
from rclpy.node import Node

from mavros_msgs.srv import CommandBool, SetMode, WaypointPush, WaypointClear
from mavros_msgs.msg import Waypoint

class MissionCircle(Node):
    def __init__(self):
        super().__init__('mission_circle')

        # Initialize service clients
        self.clear_cli = self.create_client(WaypointClear, '/mavros/mission/clear')
        self.push_cli  = self.create_client(WaypointPush, '/mavros/mission/push')
        self.arm_cli   = self.create_client(CommandBool, '/mavros/cmd/arming')
        self.mode_cli  = self.create_client(SetMode, '/mavros/set_mode')
#Creates clients for clearing missions, uploading new ones, arming, and changing flight modes, these are all one time jobs so we create clients to communicate through service

        self.get_logger().info("MissionCircle node started, preparing mission...")

        # upload_mission function is called every 3 seconds
        self.timer = self.create_timer(3.0, self.upload_mission)
        

    def upload_mission(self):
        self.timer.cancel() #we only run this function once, so once it is called after 3 seconds just cancel the timer

        # ---- 1. Clear old mission ----
        if self.clear_cli.wait_for_service(timeout_sec=5.0):
           self.clear_cli.call_async(WaypointClear.Request())
           self.get_logger().info("Cleared old mission")

        # ---- 2. Generate circle waypoints ----
        lat0 = 47.397750   # reference latitude (px4본사 취리히 좌표..실제로 날릴때는 우리자표 써야함, somehow we should be able to get it from gps or mavros message
        lon0 = 8.545594    # reference longitude
        alt  = 10.0        # altitude in meters
        radius = 0.00015   # ~15m radius in GPS degrees (~1e-5 deg ≈ 1.1 m)
        n_wp = 12          # number of waypoints around the circle

        waypoints = [] #make a list to store way points

        #the first waypoints is one just taking off
        wp0 = Waypoint()#make waypoint variable with data type of Waypoint() msg
        wp0.frame = 3                   # MAV_FRAME_GLOBAL_REL_ALT
        wp0.command = 22                # MAV_CMD_NAV_TAKEOFF
        wp0.is_current = True
        wp0.autocontinue = True
        wp0.x_lat = lat0
        wp0.y_long = lon0
        wp0.z_alt = alt
        waypoints.append(wp0) #make waypoint and add to waypoints list

        # after the initialize waypoints, the next ones are circle waypoints
        for i in range(n_wp):
            theta = 2.0 * math.pi * i / n_wp
            wp = Waypoint()
            wp.frame = 3
            wp.command = 16             # MAV_CMD_NAV_WAYPOINT
            wp.is_current = False
            wp.autocontinue = True
            wp.x_lat = lat0 + radius * math.cos(theta)
            wp.y_long = lon0 + radius * math.sin(theta)
            wp.z_alt = alt
            waypoints.append(wp)

        self.get_logger().info(f"Generated {len(waypoints)} waypoints in a circle")

        # ---- 3. Push mission ----
        if self.push_cli.wait_for_service(timeout_sec=5.0):
            req = WaypointPush.Request()
            req.start_index = 0
            req.waypoints = waypoints
            future = self.push_cli.call_async(req)
            future.add_done_callback(lambda f: self.get_logger().info(f"Mission upload success: {f.result().success}"))

        # ---- 4. Arm the drone ----
        self._arm(True)

        # ---- 5. Switch to AUTO.MISSION ----
        self._set_mode("AUTO.MISSION")

    def _arm(self, value: bool):
        if self.arm_cli.wait_for_service(timeout_sec=5.0):
            req = CommandBool.Request()
            req.value = value
            self.arm_cli.call_async(req)
            self.get_logger().info(f"ARM({value}) requested")

    def _set_mode(self, mode: str):
        if self.mode_cli.wait_for_service(timeout_sec=5.0):
            req = SetMode.Request()
            req.custom_mode = mode
            self.mode_cli.call_async(req)
            self.get_logger().info(f"SET_MODE({mode}) requested")

def main():
    rclpy.init()
    node = MissionCircle()
    rclpy.spin(node)
    node.destroy_node()
    rclpy.shutdown()

if __name__ == '__main__':
    main()

🔹 How this works

• First clears mission memory on PX4.
• Creates 12 waypoints in a circle around a reference GPS point.
• Uploads them as a mission.
• Arms the vehicle.
• Sets mode to AUTO.MISSION.

PX4 will now fly the polygonal circle by itself, even if you shut the node down.