LBL NAV - An Acoustic Transponder Navigation System

Acoustic transponder navigation systems are required in a variety of work situations including subsea surveying, mining, drilling and pipe-laying operations. This paper describes a computer controlled system called LBL-NAV, with direct application to these tasks. LBL-NAV, which is a mnemonic for Long BaseLine Navigation, is capable of simultaneously finding the position of a surface ship, a tethered subsurface vehicle (TSS) and a free-swimming submersible (FSS) in a field of acoustic transponders. Some of the specific features to be discussed include the hardware configuration as well as the navigation and survey algorithms. The navigation algorithm is capable of finding a best-fit position fix to as many as sixteen and as few as two acoustic transponders. Position reasonableness tests have been implemented in software to inhibit plotting erroneous positions. The transponder survey algorithm determines the relative position of each of the acoustic transponders from a set of raw range data.