A method of lifting device collision avoidance is disclosed. In one embodiment, the method comprises determining a three dimensional position of a collision avoidance sensor unit coupled with a load line of a first lifting device, the determining performed by a first global navigation satellite system (GNSS) receiver coupled with a housing of the collision avoidance sensor unit, generating a geofence for the first lifting device based at least in part on the collision avoidance sensor unit position, monitoring for a collision related hazard indicated by encroachment between the first geofence and a second geofence associated with a second lifting device and initiating at least one collision hazard avoidance action in response to a monitored occurrence of the collision related hazard.