The ATS II tracking system was developed by L-3 Nautronix in the mid 1990s. Whilst GPS systems were prevalent above water for offshore work they are not effective underwater, and hence an increasing demand for subsea positioning systems was of high demand in the offshore oil and gas subsea domain.
The system pioneered the development and application of ‘chirp’ signalling technology. The chirp replaces the tonal signals used in prior system with a train of chirps, each sweeping through a range of frequencies. Chirp technology provided a significant reduction in the effect of multipathing, reflection and refraction that is common in the underwater environment. This allowed for superior performance in the demanding acoustic environments of shallow water and in close proximity to structures such as drilling equipment. The system comprised of a PC based computer display system, a single vessel mounted USBL hydrophone and a number of beacons which would be located on the objects to be tracked underwater.