Fixed wing standard plan auto landing

I am using a fixed-wing standard plan configuration aircraft. I have already auto take-off it and performed auto-waypoint navigation but at the time of auto-landing, it always diverted. Can anyone guide me through the processes of auto-landing? Note: I have not integrated the DGPS

Buy a LiDAR and then Enable the use terrain parameter.

If I integrate the Lidar then there is no need to buy DGPS?

Yes. No need for increased gps precision then. LiDAR is accurate to approximately 1-5cm depending on the LiDAR model but you need to tune the landing and it only works on certain terrains (not water). You would need a radar for that (which is also available).