Stable presence sensor for outdoors

Hello Community!

Looking for the human precense sensor working outdoor in areas like garden near to the ground (10-20 cm). Tried a lot of different kinds of sensors PIR, doppler(RCWL or HB) and FMCW (HLK-LD-2410). All of them has the issue of false triggering.Indoor everything works ok, in the yard without trees and grass also, but if some grass or branches is present, sensor triggers sooner or later with no human precense. The abscene of false triggerings is critical for my application. Can someone suggest any appropriate device or trick for resolving this issue?