form_leader.xml

<!DOCTYPE flight_plan SYSTEM "flight_plan.dtd">

<flight_plan alt="250" ground_alt="185" lat0="43.46223" lon0="1.27289" max_dist_from_home="400" name="formation flight" qfu="270" security_height="25">
  <waypoints>
    <waypoint name="HOME" x="0.0" y="0.0"/>
    <waypoint name="mid" x="72.9" y="133.0"/>
    <waypoint name="wp0" x="161.9" y="35.9"/>
    <waypoint name="wp1" x="225.5" y="159.2"/>
    <waypoint name="wp2" x="57.4" y="290.9"/>
    <waypoint name="wp3" x="-79.8" y="220.4"/>
    <waypoint name="wp4" x="20.4" y="148.4"/>
    <waypoint name="wp5" x="22.9" y="69.5"/>
    <waypoint alt="215.0" name="IAF" x="239.7" y="92.9"/>
    <waypoint alt="210.0" name="AF" x="187.0" y="-2.8"/>
    <waypoint alt="185.0" name="RWAY" x="42.3" y="47.5"/>
  </waypoints>
  <blocks>
    <block name="init formation">
      <!-- formation_init() is already called -->
      <!-- init formation by adding knew slots in the formation -->
      <!-- three UAVs are expected but it can work with 1 or 2 -->
      <call fun="add_slot(21, 10, 0, 0)"/>
      <call fun="add_slot(22, -20, 20, 10)"/>
      <call fun="add_slot(23, -20, -20, -10)"/>
      <set var="form_mode" value="0"/> <!-- form mode global add_slot(id, east, north, up) -->
      <set var="leader_id" value="21"/> <!-- leader id -->
      <set var="nav_mode" value="NAV_MODE_ROLL"/>
    </block>
    <block name="cirle"> <!-- waiting circle out of formation -->
      <circle radius="nav_radius" until="FALSE" wp="mid"/>
    </block>
    <block name="start formation">
      <call fun="start_formation()"/> <!-- inform other AC that formation is started -->
    </block>
    <block name="traj" pre_call="formation_pre_call()" post_call="formation_flight()"> <!-- formation flight is call after all other navigation tasks -->
      <go from="wp5" hmode="route" wp="wp0"/>
      <go from="wp0" hmode="route" wp="wp1"/>
      <go from="wp1" hmode="route" wp="wp2"/>
      <go from="wp2" hmode="route" wp="wp3"/>
      <go from="wp3" hmode="route" wp="wp4"/>
      <go from="wp4" hmode="route" wp="wp5"/>
      <deroute block="traj"/>
    </block>
    <block name="stop formation"> <!-- when leader stop the formation, the other AC will do the same -->
      <call fun="stop_formation()"/>
    </block>
    <block name="land"> <!-- basic landing function out of formation -->
      <exception cond="(GROUND_ALT+10> GetPosAlt())" deroute="stop"/>
      <circle radius="50" until="WaypointAlt(WP_IAF) > GetPosAlt()" wp="IAF"/>
      <go alt="WaypointAlt(WP_AF)" wp="AF"/>
      <go from="AF" hmode="route" vmode="glide" wp="RWAY"/>
    </block>
    <block name="stop">
      <attitude roll="0.0" throttle="0.0" until="FALSE" vmode="throttle"/>
    </block>
  </blocks>
</flight_plan>