Overview

Prospector uses a GPS calibrated network of low cost transponders to provide high accuracy absolute positioning over a wide area. Prospector can track one surface and one underwater mobile object, such as an ROV, diver, towfish or Autonomous Underwater Vehicle (AUV). This is combined with the minimum of vessel mounted hardware and easy to use software.

Some of the many tasks that Prospector can be used for include; underwater inspection, debris searches, mapping, inshore construction work, ordnance clearance, marine salvage assessment, marine biology surveys and marine archaeology.

This simplified acoustic system is extremely easy to use and yet brings the inshore diver and ROV operator the same advanced Sonardyne technology used to save time and money in most of the world's offshore oilfield developments.Four acoustic transponders are deployed on the seabed with surface or sub-surface floats to form an underwater navigation network with each transponder being deployed at one corner of a square. The positions of these four transponders are then calibrated by sailing the vessel briefly around the square (typically in under 20 minutes).

Features & Benefits

Low cost system

Quick to deploy

Easy to calibrate

Highly accurate

Compatible with the Coastal Acoustics range of low cost positioning systems, release transponders and Scout USBL tracking system

A Typical Prospector System

The components of a Prospector system are an acoustic transceiver, Surface Interface Unit (or SCU), four transponders and Windows-based software. A computer and Global Positioning System (GPS) receiver are also required. All the equipment is supplied in a rugged case for ease of transport and storage.

Transceiver
The transceiver is the electronics module that is fitted to the diver or ROV. A connector on one end of the unit provides power and communication to the SIU while the other connector is used to attach the acoustic transducer. The transducer is the part that actually transmits and receives the acoustic signals.

The transceiver’s transducer sends an acoustic interrogation signal to a transponder through the water and receives an acoustic reply signal back from the transponder. By measuring the time between sending the interrogation and receiving the reply the transponder’s distance can be determined.



Surface Interface Unit (SIU)
The SIU provides power and a communications link between the transceiver and the computer running the Prospector software. The SIU connects to the transceiver over a long cable fitted with a waterproof connector and to the computer using a USB link.
Four additional serial ports are included that can be used to connect to external instruments.



Transponders
Prospector is compatible with either Coastal or LRT transponders . These can be deployed in a maximum water depth of 500 metres and either mounted in fixed seabed stands or supplied with release hooks for easy recovery on the surface.

Computer and Software
The computer running the Prospector software connects to the SIU using a serial communications cable. The software on the computer talks to the transceiver via the SIU sending it commands to make it measure acoustic ranges to transponders. The software also takes the range measurements made by the transceiver and calculates the position of the transceiver from them. The boat, the transponders and a chart of the working area can be displayed on the computer’s monitor.

Global Positioning System (GPS) Receiver
Positions from a Global Positioning System (GPS) receiver are used when determining or ‘calibrating’ the positions of the transponders just after they have been deployed. The GPS receiver is fitted to the boat and provides position measurements in real-world co-ordinates. The GPS receiver connects to the SIU via a serial port.