Tracking system for a pipeline

A tracking system for use with a pipeline comprising:

• a scraper having signal generating means for generating an acoustic signal, said scraper having a size suitable for fitting within and traveling in a path along the pipeline;
• a plurality of acoustic pressure sensors positioned at intervals along the path traveled by said scraper, said, plurality of acoustic pressure sensors suitable For sensing the acoustic signal from said scraper;
• a plurality of local processors positioned at intervals along the path traveled by said scraper, each of said plurality of local processors being in communication with at least a respective acoustic pressure sensor of said plurality of acoustic pressure sensors;
• and
• a central processor in communication with said plurality of local processors, said central processor suitable for generating an output indicative of a location of said scraper within the pipeline.