Method for retrieving predetermined locations in sewer and pipeline systems

摘要

A method for retrieving predetermined locations in sewer and pipeline systems after application or deposition of a layer of material. A carrier vehicle having a microwave sensor emits microwave signals and receives backscattered microwave signals. A first run is conducted inside the sewer or pipeline system before application or deposition of the layer of material. A first temporal signal profile of the backscattered microwave signals is recorded and the sought locations are marked in the first signal profile. After the application or deposition of the layer of material, a second run is conducted. A second temporal signal profile of the backscattered signals is recorded. The current position of the vehicle in the sewer or pipeline system relative to the sought locations is determined by comparison with the first signal profile.