Make target px4_sitl_rtps not found

Hi I am following the instructions present Ros2 User Guide https://docs.px4.io/main/en/ros/ros2_comm.html .

  • I have installed Ros2 foxy, cloned the PX4 firmware and have setup the dev environemnt using ubuntu.sh.
  • I have also installed fastrtpsgen and built the Ros2 workspace for px4_ros_com & px4_msg packages.

But as i go through sanity check the installation, I get his error on the first command.

prakrit@prakrit-GL553VD:~/Developer/PX4-Autopilot$ make px4_sitl_rtps gazebo
Makefile:523: *** “Make target px4_sitl_rtps not found. It either does not exist or px4_sitl_rtps cannot be the first argument. Use ‘make help|list_config_targets’ to get a list of all possible [configuration] targets.”. Stop.

Please Help !!!