Comment by asdefghyk

How did ships navigate 200 years ago? Not sure how accurate it was ?

How about using the stars? ... only at night ?

Use triangulation to known RF transmissions ( ie like direction finding of RF signals )

Geography recognition , rivers mountain's . towns etc ( Lidar ? )

Broadcast this info on some other secret frequency - drones only need to listen to the info

Use radar to track drone and broadcast its position to the item ...