Benthos
The new C3D from Benthos offers bathymetry and sidescan sonar integrated into one system for towed or fixed-mount operation. The extension of swath bathymetric sidescan (SBS) sonar systems to multiple angles-of-arrival has resulted in substantial improvement of the performance limits (resolution, swath width, and accuracy) of conventional seafloor mapping and imaging systems, particularly in shallow water.

The C3D uses Small Aperture Range Angle Computed Angle of Arrival Transient Imaging (SARA CAATI). CAATI is a method for estimating the backscatter arrival spectrum. The underlying principles of CAATI are derived from the broad fields of high-resolution spectral estimation and angle-of-arrival estimation.

In a number of 2D sonar imaging applications (sidescan, sector-scan), CAATI provides a method to add the third dimension, vertical relief, using only a small number of vertical array elements. Instead of beamforming in the vertical plane, CAATI utilizes angle-of-arrival estimation in a fashion similar to interferometry. Like interferometry, CAATI assumes a time-varying impulsive spectral model. However, while interferometric systems are rendered ineffective by concurrent arrivals from multiple angles, CAATI is able to resolve as many as N-1 arrivals with an N element array (e.g., with three elements a direct path and multipath can be separated).

The C3D system can be used for hydrographic survey, cable and pipeline surveys, engineering and scientific studies, biomass for fisheries, block clearance, bridge inspection, and object detection. The system's features include a streamlined design that is stable at speeds from one to 10 knots, yet is lightweight and portable. The towfish is designed with a stainless steel frame and fiberglass shell. The over-the-side mounting design has stainless steel piping and frames. The modular design allows expansion with any industry standard motion reference unit, pressure sensor, magnetometer, CTD, etc.

The unit also offers flexible communications capabilities. With a standard ethernet connection, it can interface to off-the-shelf data acquisition systems. Its multiple operating frequencies include 100, 200, or 300khz. Visit www.benthos.com for more information.

RD Instruments
RD Instruments (RDI), a leading manufacturer of Acoustic Doppler Current Profilers (ADCP) and Doppler Velocity Logs (DVL), offers a wide range of acoustic solutions for measuring water in motion and motion in water.

For over a decade, RDI's DVLs have been used for a variety of survey and navigation applications operating from a wide array of platforms, including ROVs, AUVs, swimmer delivery vehicles (SDV), towed bodies, diver systems, and submarines. They are also an essential component of many surface vessel navigation and survey systems in use around the world.

RDI's Workhorse Navigator DVL is a small, light, multi-function sensor that gives precise velocity and altitude updates. It is ideal for survey applications requiring real-time vehicle control capability, or the ability to maintain highly accurate navigation on a survey line.

The Navigator DVL provides high rate positioning using patented broadband signal processing, which enables precise tracking and velocity data to be obtained by referencing its position relative to the seafloor. Patented bottom-detection algorithms combined with single-ping bottom location allows the DVL to relocate the bottom on a ping-by-ping basis, providing reliable bottom tracking in changing seabed conditions and uneven terrain.

The unit automatically adjusts for scenarios where high-volume backscatter is generated, such as disturbed sediment and low visibility conditions. Its four-beam configuration provides beam redundancy, allowing continued operation in the event of a blocked beam or beam failure, and continued bottom tracking in irregular seabed topography.

In surface vessel applications, the RDI DVL produces continuous high-rate "dead reckoning" positioning data, providing positioning during periods of GPS outages or shading. This data can also be used to ameliorate other positioning data. The unit can be used either stand-alone or integrated with existing navigation systems, including long baseline (LBL), ultra-short baseline (USBL), and inertial navigation systems (INS).

The RDI Workhorse Navigator is ideal for wide area surveys, pre- and post-burial pipeline surveys, cable route surveys, pipeline touchdown monitoring, AUV reconnaissance, underwater search operations, and mine countermeasure operations. Visit www.rdinstruments.com.

MacArtney
The MacArtney Nexus MKX is a plug-and-play multiplexer system for ROVs. An extension of the successful Nexus MKI model, it is based on development between MacArtney and major ROV operators.

The Nexus MKX is designed to be the main vehicle multiplexer for a work class ROV, and will fit new and upgraded older systems. The easy installation of the system can help significantly when large ROV mobilizations require additional cameras, sonars, attitude sensors, manipulators, cable and pipe trackers, etc., to be installed.

The multiplexer system is built on a Focal Model 903 and a micro controller, and includes a topside unit and an underwater unit. The topside unit consists of a 19-inch rack with a power on/off switch on the front panel as well as various light diodes for status indication. On the back panel, a number of D-sub connectors are installed for serial data, analog and digital input/outputs, and BNC connectors for video output. Some of the serial data channels are accessible via connectors in the Focal Model 903.

Control of camera functions and sensor power is performed by connecting existing switches from the ROV system panel to the back panel of the Nexus topside unit. The micro controller topside PCB reads this information, and the unit uses one serial RS232 for communication with the subsea micro controller PCB, which has relays for sensor power on/off as well as control of camera functions.

The underwater unit is an aluminium bottle depth-rated to 10,000 feet (3,000m). The bottle includes all the electronics for the multiplexer, control system, video transmission system, and power supply. Four multi-conductor harness cables are routed to an oil-filled junction box, also rated to 10,000 feet (3,000m). This box has 12 Subconn connectors for sensors and one for power input to the complete system.

Features include 16 RS232 duplex channels, one Tritech Arcnet, three RS485/422 channels, eight video channels, two (P)ECL uplinks (multibeam sonars), and optional ethernet. Visit www.macartney.com.

Hydroid
Hydroid's powerful new survey tool, the Remus autonomous underwater vehicle (AUV), weighs in at less than 80 pounds. The vehicle is small enough to be carried by one person, yet contains enough sophisticated sensor, navigation, and power resources to enable it to perform detailed sonar, environmental, and oceanographic surveys over a large area. Remus operates at depths of up to 330 feet (100m) at speeds of up to five knots, and can cover 60 nautical miles in a single survey mission.

Although the vehicle can be custom configured to meet unique mission requirements, the typical vehicle contains a standard suite of survey instrumentation, including a Marine Sonic Technology 600, 900, or 1,200khz sidescan sonar. This sonar was developed in cooperation with Woods Hole Oceanographic Institution, with support from ONR in 1999.

Careful attention was paid to noise and interference minimization to provide the highest possible fidelity sonar data. All other acoustic systems are synchronized to the sidescan transmissions to eliminate interference on the images. A set of custom hull-mount transducer modules was developed for Remus to minimize drag and weight. The frequency is easily changed by swapping the central hull-section and the sonar transceiver board.

All sonar functions are software controlled and may be programmed during the mission-planning phase. The Sea ScanR PC software is used to operate and record sonar images during a mission. Sea ScanR PC Review is used to view and analyze the sonar images. The user can click on a possible target and automatically create a text file that contains the target location, operator comments, and a link to a snapshot image of the target. This data file is then imported into the Remus Report generator program and automatically included in an output HTML report. Sidescan data can also be downloaded into a wide array of commercial off-the-shelf software programs for added post-processing capability.

Remus also includes a 1.2 MHz RDI Acoustic Doppler Current Profiler (ADCP) with down-looking and up-looking transducers. The ADCP allows the vehicle to measure water velocity and direction above and below to a range of approximately 18m. It also provides echo intensity, which (along with current velocity) may be reported as a function of depth. The sensor measures the velocity of the vehicle relative to the bottom, as well as its altitude above the bottom. The velocity informationn and heading are used to compute the absolute magnitude and direction of the current.

In addition, the velocity information relative to the seafloor provides a very accurate dead-reckon navigation input. The altitude measurement, when coupled with the vehicle's position and depth, provides the seafloor bathymetry, and is also used as an input to the vehicle controller when operating in constant-altitude mode.

In standard configuration, the vehicle is equipped with an Endeco/YSI model 600 XL multi-parameter sensor sonde, which has temperature and conductivity sensors. The control computer provides sensor depth (using its on-board pressure sensor), time of day and navigation data, providing a geographical fix (x,y,z) for the data that is logged in the vehicle log file. Higher accuracy sensors are also available depending upon requirements.

The vehicle's light scattering sensor is manufactured by WET Labs. The lightweight, low-power sensor measures the reflectance of turbidity and suspended solids in the water, or the ratio of the magnitude of projected light to that received by the detector. The sensor has two modulated 880nm wavelength sources that project light out of the side of the vehicle. As the light travels away from the vehicle, some of it is scattered as it hits particles in the water. The light that is scattered back toward the vehicle is detected by a solar-blind light detector, which permits the sensor to be used during the day.

The vehicle is programmed and monitored using software on a standard laptop computer. Despite the impressive survey payload, Remus boasts an easy-to-use operator interface with complete system diagnostics, mission planning and programming, data upload and processing, and HTML mission report generation. Collected data is compatible with a wide array of standard hydrographic post-processing programs.

For more information, visit www.hydroidinc.com.

Stenmar Sonavision
Stenmar Sonavision's new compact Mercury scanning sonar and Minerva surface control unit have been integrated with the equally compact VideoRay Pro II ROV.

Barely the size of a soda can (79mm diameter by 140mm long), the Mercury is the world's smallest frequency-tuneable 360-degree scanning sonar. Tuneable in 1kHz steps from 600 to 1200 kHz, Mercury can locate long-range obstacles up to 100m and high-resolution capabilities for short ranges. It comes rated to 1,000 feet (300m) with a plastic housing, 3,280 to 10,000 feet (1,000-3,000m) in a stainless steel housing, and 19,680 feet (6,000m) in a titanium housing. This makes it ideal for use on the VideoRay and smaller observation class ROVs and AUVs, yet powerful enough for larger observation and work class vehicles.

Gilgeous Diving Services (England) used a Mercury-guided VideoRay Pro II on three recent projects. For one project, Gilgeous located the wreckage of a private aircraft lost years ago in the Moray Firth area. The company is also using the VideoRay for an ongoing project in the North Sea.

Since its launch a few months ago, more than 25 Mercury sonars have been supplied to a broad range of ROV, AUV, and military clients for applications including ROV surveying, mine detection, and detonation work. Stenmar Sonavision is also developing a hand-held version of Mercury for commercial divers.

For more, visit www.stenmar.com and www.videoray.com.

GeoAcoustics
GeoTexture, the latest software from GeoAcoustics, allows sidescan data to be processed to determine areas of similar seabed characteristics. The user-friendly software can be applied to any sidescan image, as well as data produced by the GeoSwath wide bathymetry system.

The accompanying image shows a sidescan output taken over an area with a field of sand ripples deposited over a more uniform and reflective area. Local fishermen put down strings of lobster pots on the sand wave area. These can be easily seen at this resolution (fairly typical for 100khz sidescan). The GeoTexture software can read the sidescan data and, having been rapidly "trained" by arbitrarily selecting small but visibly different textural areas, can recognize matching primitive textures over the whole area (soft/hard sediments, etc.). This process took about five minutes. The lobster pots show up as small "pools" of unrecognized texture when the image is classified.

Any number of successive files can then be easily classified, and similar features highlighted automatically. The texture analysis software works almost down to pixel resolution. An added benefit is the mapping of soft or mobile sediment areas where buried objects may be present, which may not be seen on sidescan data.

The purpose of the survey was to obtain accurate bathymetry of the harbor using a 250khz GeoSwath, but the high resolution sidescan is an automatic by-product. Survey plan is the same as a normal sidescan survey - roughly 40m line spacing in depths of 26 to 32 feet (8m to 10m). In this instance, the classification process has worked on the mosaic output rather than the raw sidescan files, and is on the right of the unclassified data. The image shows classified sediment types for geophysical interpretation, with all unclassified data shown as grey. Figure 3 is a zoomed section of this data where unknown small objects have been automatically highlighted.

The advantages of GeoSwath sidescan data are the accurate attitude, heading, and position correction, as well as the ability of the system to move between bathymetry and sidescan as they are co-registered at the full system resolution. All of these advantages lead to better registration of the mosaic.

Kongsberg Simrad
Norsk Hydro recently contracted Stolt Offshore to perform AUV seabed charting in the Storegga slide. For the AUV portion of the project, Stolt Offshore subcontracted with Norwegian Underwater Intervention (NUI), which operates a Hugin-2 prototype that has been modified and renamed the NUI Explorer.

Ultra-deep oil and gas exploration and production faces a significant challenge of installing subsea production equipment and transport pipelines in rough and complex seabed terrain. The pipeline systems to bring the product ashore often have to cross steep escarpments leading to shallower continental shelves. As a result, detailed knowledge about seabed conditions becomes a key factor affecting the engineering and construction activities. Identification of the most optimal site and pipeline route means lower construction costs.

Nearly 1,000km of multibeam echosounder and sub-bottom profiler data was successfully collected in water depths of 820 to 2,788 feet (250 to 850m) in extremely difficult terrain. The data quality was very good and the operation efficient. Typical charting speed for the NUI Explorer AUV was 3.7 knots. The 10,000-foot (3,000m) vehicle features a Kongsberg Simrad EM3000 Multibeam Echosounder, which provides a swath width of more than 100m at 50m height. The EM3000 also offers optional integration of other types of sensor equipment like sub-bottom profilers and sidescan sonar. Visit www.kongsberg-simrad.com.

VT TSS
The new TSS 440 cable and pipe tracker has a range up to 50 percent greater than its predecessor, the TSS 340. Nearly 200 of the TSS 340 model are in use by the worldwide oil and gas and submarine cable industries to locate and survey on or below the seabed at water depths of up to 10,000 feet (3,000m). Development of the new 440 model was initiated to create a system capable of locating pipes and cables that are buried more deeply or laid in more difficult locations.

The principal difficulty overcome by the VT TSS development team was the effect that seawater has on the pulse induction technology used by the TSS 340. The pulse induction technique uses a system mounted on an ROV that flies as low as possible over the seabed. Powerful electromagnetic pulses pass through the seafloor and, on reaching a metallic object, cause electrical eddy currents to be generated within it. These currents create a small electrical discharge, which the 340 would measure and use to compute the depth and position of the pipe or cable.

However, it was not possible to increase the range of the TSS 340 simply by increasing its power output. This is partly due to the physics of pulse induction, which demand a tenfold increase in voltage output to achieve a doubling of detection range. This problem is made worse by the mildly conductive effect of seawater, which also causes eddy currents to be generated within the water itself. These could be calculated for elimination, but for the variations in water conductivity caused by changes in the height at which the ROV flies above the seabed. Variations in seawater temperature and depth also affect its conductivity and make its effect during a survey unpredictable.

Consequently, a new mathematical technique was developed at VT TSS following experiments performed to study the rate at which eddy currents decay in seawater. By developing a new calibration process for the 440 model and exploiting the difference in electrical response from the target and the surrounding water, the VT TSS team created an algorithm that largely overcomes the problem. Depending on the size and shape of the target, the new 440 offers detection ranges 30 to 50 percent greater than the 340 model. This means that it can also deal with the potential errors that arise when a cable is in an open trench or passing through a rock berm.

Statoil, DeepOcean, and Global Marine Systems contributed significant help in the development of the TSS 440, assisting with user input and sea trials. The new system includes a number of practical improvements such as system processing being handled topside where making corrections is possible. New Windows software makes the system easier to use while more sensitive search coils and TSS altimeter give the hardware a significant improvement.

SRD
The new SVS2 system provides a flexible approach to sonar visualization, giving the user an accurate and readily understandable representation of remote complex underwater operations in real time. It is produced by SRD (UK), and is a further development of the firm's award-winning Seabed Visualization System.

SVS2 is based on the acquisition of high precision sonar data (range, bearing, and amplitude), allowing simultaneous observation and tracking of multiple targets. Systems can be fitted on surface vessels, AUVs, ROVs, or seabed burial and excavation tools.

Of the wide variety of possible applications of SVS2, a number have already been realized. A variant, the Autonomous Visualisation System (AVS), is a compact, low-power AUV payload for swath bathymetry and forward-looking obstacle avoidance. This system was installed on the Maridan M600 AUV owned by De Beers Marine.

SRD's Pipelay Support and Pipe Exit Monitoring Systems, both providing valuable information for pipeline touchdown, are currently on deepwater projects in the Gulf of Mexico.

At the heart of SVS2 lies a comprehensive, multi-tasking surface control system that links to a project-specific configuration of electronics modules and sonar sensors designed for the tasks required. The independent triggering and interrogation sequence of all sensors can be controlled simultaneously.

This flexible system architecture is supported by one of the most adaptable software packages available. Designed in-house, SRDView controls the visualization element of the overall system, allowing full integration of sensor inputs to produce a powerful and more meaningful engineering tool in terms of real-time measurement, monitoring, and control. Developed during a wide range of past projects, sea trials, and test-tank simulations, an ever-growing library of programs can be enabled and incorporated into a bespoke system to address specific requirements.

SRDView defines "subjects" or tasks within the Whole Field Model (WFM) viewing environment, providing the capability for advanced precision acoustic positioning and tracking of subsea targets and structures, and to view all activities as a dynamic three-dimensional database. At the simplest level, such subjects could include static entities such as seabed topography or fixed seabed structures.

However, dynamic tasks can also be addressed, such as pipe or cable tracking during lay operations; dredge-head monitoring; surface, sub-surface and seabed vehicle tracking; and real-time topographic monitoring during trenching, jetting, or rock-dumping activities. The user is given an infinitely variable static or dynamic viewpoint of the WFM from virtual cameras.

SRDView software can also be integrated to clients' or third-party systems, bringing the benefits of an enhanced online system incorporating:

• Real-time 3D visualization and modelling of all aspects of the offshore project
• Real-time comparison of ongoing project with simulated or design requirements
• Data analysis tools, volumetric calculations, difference DTMs, etc.
• Visual tools, cross-sectional and longitudinal profile displays navigation displays, etc.
• Error models to refine the sonar acquisition processes
• Database utilities to store time- and position-relative data such as video, images, spreadsheets, text documents, hyperlinks to external data.

The system is also an effective offline system design and planning tool for:

• Review and analysis of existing data
• Project simulation/rehearsal using a time line and flight paths to enable a clearer understanding of hazard areas before the project starts
• Calculation of project timings to allow greater costing control
• Training
• Production of 3D animations for marketing and final deliverable requirements.

The result is the ability to maximize the amount of useful information that can be extracted from often costly-to-acquire data.

Reson
In preparation for the University of New Hampshire Shallow Water Survey 2001 conference in Portsmouth, New Hampshire, a dual-head Reson SeaBat 8125 system collected some spectacular data that became part of the Portsmouth Harbor Common Dataset. Collected on the Piscataqua River in July 2001 during a joint Reson/SAIC operation, the survey's purpose was to demonstrate the high-resolution capabilities of the SeaBat 8125.

Operating at 455kHz, the SeaBat 8125 is the first wide-sector, wide-band, focused multibeam sonar. The system measures a 120 degree swath across the seafloor, detects the bottom, and delivers the measured ranges at a depth resolution of 0.5 by one degree. The system can be mounted on a survey vessel or ROV and is rated to depths of 4,920 feet (1,500m).

In 1991, Reson introduced the first of the SeaBat series of high-performance multibeam echosounders. Its compact size, speed, accuracy, and resolution set new standards in the offshore and hydrographic sector. With more than 400 systems in use worldwide, Reson offers both bathymetric multibeam echosounders and multibeam forward-looking sonars.

The HydroBat series is a line of fully integrated hydrographic survey systems built around the SeaBat Multibeam Echosounder. Every HydroBat system is a carefully selected, factory-tested blend of components. Systems are available off-the-shelf for a wide range of budget and survey accuracy requirements, all backed by Reson's worldwide support network. The systems can be delivered with full installation, calibration, training and warranty.

With the recent acquisition of a majority share in Navitronic Systems A/S, Reson added NaviSound single-beam echosounders, sound velocity probes, and NaviSoft hydrographic software to a product line that already included specialty transducers, precision reference hydrophones, and data acquisition software.

Marine Electronics Ltd.
UK-based Marine Electronics is now in its 20th year of specializing in underwater acoustic systems, including sonars, altimeters, releases and transponders.

The company recently supplied its Dolphin 6201 system to Subsea 7 for the Geosub autonomous survey vehicle (ASV), which is undergoing sea trials before entering commercial service. Subsea 7 is developing Geosub for work in the oil and gas and subsea cable markets with initial emphasis on deepwater site and route surveys. The navigation systems will be further refined to allow autonomous pipeline inspection using advanced sonar, video, and profiler techniques. The starting point was a 10-year license agreement with the UK's Southampton Oceanography Centre for access to the technology developed for the proven Autosub research AUV project. The Geosub ASV is 22 feet long, rated to 10,000 feet (3,000m), and has a deployment time of at least 24 hours.

SociŽtŽ Eca's Olister ROV was fitted with a Marine Electronics Dolphin 6001 sonar. Eca's Olister/Alistar range of vehicles are available in military and civilian versions. Typical missions include pipeline touchdown monitoring, underwater inspection, and salvage tasks. Much empahsis is placed on the high performance navigation system based on Doppler/inertial navigation fusion, ultra-short baseline acoustics and the Dolphin 6001 combined imaging and collision avoidance sonar/altimeter system. This offers real-time continuous scanning over a 90 degree sector at 30 frames per second. On the Olister ROV, power is supplied either from the vehicle or via an additional two power cores through the umbilical. The system software can log raw data to disk at full resolution for post analysis. There is also a suite of on-screen measurement tools.

The 10,000-foot (3,000m) rated Dolphin 6201 sonar was developed specifically for AUV navigation. It fits into the nose cone of the vehicle and is unique in that it has both a dual beamwidth sonar transmitter coupled with a multi-element receiver and forward-looking altimeter. This enables the instrument to perform not only obstacle avoidance but also act in inverse mode to automatically track to a target such as a wellhead.

In obstacle avoidance mode the Dolphin 6201 is the only commercially available instrument capable of scanning continuously over a 90-degree sector up to 200m ahead, while simultaneously identifying up to 250 discrete sonar targets. Each target is assigned an ID number and monitored for range and bearing until it disappears.. Another unique feature of the Dolphin 6201 is that when targets in the "protected" corridor in front of the vehicle are analyzed as presenting a threat, a collision avoidance message is output to the AUV's navigation computer via the Dolphin PC104 processor housed in the pressure hull of the AUV. All raw data is stored in the processor for post-mission analysis.

In inverse tracking mode, the Dolphin sonar may be programmed to track to a target, using a combination of the sector scanning sonar and the forward-looking echosounder to home in. The built-in altimeter also provides valuable height-above-seabed data.

The Dolphin 6201 sonar is also used on ROVs, where an ethernet link allows the surface operator to view raw image data from each frame. The system operates at 250kHz with a range resolution of 25mm, angular resolution of 1.5 degrees and sample rate of 2MHz. The stainless steel underwater unit is 220mm diameter x 142mm and weighs 21.5kg in air, 17.2kg in water.

Marine Magnetics
Marine Magnetics has released its new Explorer mini marine magnetometer. The Explorer was designed to provide cost-effective survey operations for shallow inshore work. The unit's compact size of 33.75-inches and lightweight of six pounds ensures it can easily be deployed from a small craft by one person.

Explorer's high sensitivity, excellent accuracy, and the ability to operate around the world without any restrictions makes this digital mini marine magnetometer a professional tool. A complete system with 164 feet of detachable tow cable runs US$14,500.

An Explorer mini marine magnetometer with interface to the Klein Associates 3000 was recently purchased by GSE Rentals in the UK. GSE already has a fleet of Marine Magnetics' SeaSpy marine magnetometers in its subsea equipment rental pool.

Omnitech merges with CodaOctopus
Omnitech, known for its Echoscope 3D imaging sonar, has merged with CodaOctopus of the UK, a leading manufacturer of software and systems for geophysical imaging and mapping. This move builds on the July 2002 merger of Coda Technologies and Octopus Marine.

Omnitech will continue to be based in Bergen, Norway, though relocated to new water-side premises close to the city center. All key staff has been retained, including Rolf Kahrs-Hansen, Poul Andersen, and Erik Eknes. As the new center for all CodaOctopus Scandinavian operations, Omnitech will focus on development and support of the Echoscope 3D imaging sonar, drawing on the extensive CodaOctopus worldwide sales and support network.

CodaOctopus is also providing field support services to clients. The new services include consultancy for Coda GeoSurvey clients, mobilization of the new F180 inertial attitude and positioning system, training courses, and sea trial support.

Linkquest
LinkQuest's 9600-baud underwater acoustic modems offer a new way of uploading a large amount of data from self-contained profiling ADCP units, without retrieving the sensors from the deployment site. Uploading the data from a surface ship using acoustic modems has proven to be practical and reliable. LinkQuest's high-speed modems allow the user to collect two to three megabytes of data on-site within an hour and a half.

LinkQuest provided three of the subsea UWM1000 modems to Walsh Environmental. Each of these modems was connected to an RDI Workhorse ADCP off the Louisiana coast in depths from 33 to 49 feet (10 to 15m) in September 2002.

Oceanographers visit two of the sites every two weeks to upload about two megabytes of current data at each site and visit the third site every four weeks to upload three or four megabytes of data. By sending commands from LinkQuest's Windows software through the surface modem hung from a vessel, the oceanographers can upload the data easily, without retrieving the ADCPs. The parameters of the ADCP were also flexibly adjusted during the visits. In total, about 100 megabytes of data were collected during the six-month period. The maximum size of data collected in a single visit is about eight megabytes. Visit www.link-quest.com.

Sonardyne
One of the most important pieces of acoustic technology used offshore is the transponder. It is the central component used in all subsea positioning tasks and a fundamental tool for the dynamic positioning of rigs and platforms.

After a long development program, Sonardyne International has launched the Compatt 5, a new transponder with benefits that users have been waiting for a long time.

Based on a new mechanical and electronic design, Compatt 5 brings major benefits and cost-savings to underwater acoustic navigation, including dramatically faster setup, commanding, and array calibration. It will provide more channels and enable complex multi-user and multi-array operations. Above all, Compatt 5 provides a flexible platfor' on which to run all foreseeable future developments in underwater navigation, enabling users to remain up-to-date for many years to come.

The new model is shorter, lighter, and deeper-rated than Compatt 4, and features a flange-less pressure housing to simplify installation into subsea transponder buckets and provide ease of handling, especially by ROVs. The advanced electronic circuitry operates both with Compatt 4's toneburst signals and, by use of DSP chips with new broadband, spread-spectrum signals.

A new battery pack provides greater reliability and has its own memory, recording how much capacity remains, even if removed and replaced in another unit. Battery changing has been simplified to make the procedure faster without exposing the transponder's electronics. Because software downloading over the Internet is expected to become the principal way of upgrading performance, flash memory allows new software to be installed without opening the pressure housing.

A hidden, but important feature of Compatt 5 is the new acoustic architecture on which it has been designed to operate. This is the combination of frequency channels and signal sequences for commanding transponders, interrogations and replies, and data telemetry from the seabed.

New ship-borne and ROV transceivers are already available to support the new architecture, together with Pharos navigation software, and are known as the Fusion family of systems. The Fusion concept is applicable from single arrays to wide-area installations covering entire oilfields and for multi-vessel simultaneous use. By using broadband, spread-spectrum signals, these systems will provide dramatic improvements in speed and operating efficiency of underwater navigation operations.

Although Compatt 5 represents a major technological advance, Sonardyne has recognized the need to protect customers' existing investment in equipment. The first Compatt 5s are therefore delivered operating in Compatt 4 mode, but with additional channels, alternate CIF commands, status locking commands, higher telemetry data rate, improved depth sensor accuracy, and depth sensor re-calibration via RS232. A new intelligent sensor end-cap comes equipped with more sensors than previous models and is able to take faster readings from optional high-accuracy quartz pressure sensors and inclinometers. The circuit boards are plug-and-play, with just one firmware version supporting all Compatt configurations. As customers build-up inventories of Compatt 5 and begin using it with the new Fusion generation of positioning systems, the full potential of Compatt 5 can be unlocked.

Maxsea
Maxsea is a powerful navigation tool with unique abilities and user-friendly concepts ideal for commercial underwater surveyors. It functions as a central brain for the survey boat, bringing various charts, instrumentation, and user data together into one simple tool. Maxsea allows the use of various types of raster and vector charts, which are stitched together seamlessly to make the transition from chart to chart extremely smooth. Maxsea requires a GPS, but can also be interfaced with echosounders, radars, and other subsea sensors.

One advantage Maxsea has over other navigation software and conventional plotters is that it allows its user to work on many different data files simultaneously. This ability to work in layers makes it easy to create and display track and marks files at the same time while saving them separately and keeping them better organized.

One of the most unique features of Maxsea is the way it handles and displays bathymetric data. Since it works in layers, the user can complement the navigation chart by overlaying historic bathymetric data on top of it (based on NOAA track-line information). The user then has the ability to update this bathymetric information in real time and on the fly. The program will take inputs from an echosounder and update this historic data. This information is then saved in a user database and will continue to be updated. This bathymetric data (both historic and user) can then be texturized into a 3D window. This allows the user to more easily visualize the depth and corresponding bottom terrain around them. The 3D image can be rotated 360 degrees in two planes, as well as zoomed in and out.

Maxsea can also interface with bottom discrimination hardware, such as SeaScan. SeaScan allows the user to conduct ground discrimination and thus determine the bottom type. This can save the user a lot of time searching for certain bottom types by trial and error. The ability to see the depth information in 3D allows the user the flexibility to dedicate the color-scale to bottom makeup. A Maxsea user can therefore not only see the depth and underwater terrain in 3D, but can also display the bottom makeup simultaneously in the form of various colors.

Coastal Oceanographics
The new HyPack Max version 2.12 is now available from Coastal Oceanographics. The powerful hydrographic software package is used for survey design, data collection, graphical editing, plotting, volume computations, surface modeling and contouring.

The major change to HyPack Max version 2.12 is the new 3D Terrain Viewer (3DTV). This new data visualization tool allows the user to view in 3D any XYZ data file. You can fly the camera manually or down a planned line, or you can use the Survey Program to position the camera in real time using the position and heading of the vessel. The user can also create a semi-transparent water surface and vary the level and opaqueness of the surface. This can be changed on the fly for a very nice effect.

Other features include added interfaces for Reson 81 series sonars, Seabeam 2100, Kongsberg Simrad's EM2000/3000, and the Tritech SeaKing. Many new drivers allow the user to display multiple vessels or vehicles in Survey Mode by reading network NMEA messages. Also, the new Channel Condition Reporter searches for shoals as required by NOAA for all federal channels.

SeeByte
SeeByte (UK) has developed the SeeTrack modular multi-sensor processing and visualization software for underwater vehicles and platforms. The Windows-compatible SeeTrack system is designed for users who need to rapidly visualize multiple concurrent data products from underwater vehicles or towed platforms in a simple, intuitive fashion at comparatively low cost.

Unlike other systems, SeeTrack supports concurrent data visualization from sidescan sonars, digitized video, acoustic cameras, CTD, and bathymetric sensors. It includes sophisticated terrain-based navigation post-processing for accurate video and sonar mosaicing and geolocation. Mission planning facilities are also included, as well as automated event detection to reduce time and effort searching large data sets. Its modular architecture mean that new sensors can easily and rapidly be integrated into the overall picture, and results exported in html format for ease of distribution.

SeeTrack's portability, integrated approach, and ease of use make it an ideal choice for environmental assessments and survey applications, including hydrographic, offshore, marine science, pipeline, ports and harbors, and security reconnaissance.

The system has been used extensively in major US Navy field battle experiments and NATO trials using a variety of vehicle platforms. Its modularity is a major requirement when data from multiple vehicles or platforms have to be integrated into a common environment. At the heart of SeeTrack is a system enabling the gathering of any information through the development of specific drivers. The SeeTrack Core can access this data and process them using plug-ins. The output of the processing is ready to be displayed by the user interface or exported to external systems.

Geographical information systems design wa a key development feature. Most missions will require geo-location of potential targets for reacquisition and data fusion. Mission planning also requires geographical coordinates. More importantly, legacy data is in general available and should be used as much as possible to plan and confirm the mission outcomes. SeeTrack is developed using geographical information systems libraries, enabling most standard formats and legacy data to be imported and exported.

SeeTrack has an easy to use interface and data can be viewed in both 2D and 3D. Users can access data from any mission, process them and export the results in only a few clicks. The system requires only a standard laptop to run.

SAIC's Marine Science & Technology Division
Science Applications International Corporation's (SAIC) Marine Science and Technology Division (MSTD) has developed two unique surveying and processing products, ISS-2000 and SABER, to provide professional hydrographers and surveyors with powerful, accurate, and efficient tools for planning and executing surveys, and for processing and analyzing survey data.

SAIC's ISS-2000 Integrated Survey System supports a broad range of high-performance shallow and deepwater survey operations including search, mapping, and charting. ISS-2000 has proven International Hydrographic Organization (IHO) accuracy in high speed, shallow water surveying and processing operations. Powerful acquisition and visualization capabilities give ISS-2000 higher efficiency and data yields while maintaining real-time quality assurance.

ISS-2000 offers a range of survey planning capabilities and data collection features. Its modular components are offered in price-performance packages that include fully integrated sensor suites with data acquisition systems and software, and which are scalable to transportable models. Compatible with SABER, ISS-2000 interfaces to internationally recognized sensors including both multibeam and singlebeam echosounders, GPS receivers, motion sensors, gyros, acoustic positioning systems, and autopilots.

SAIC's SABER (Survey Analysis and Area-Based Editor) processes, edits, updates, views, and analyzes hydrographic survey data. SABER efficiently processes massive data volumes and allows the operator to view the data geographically, review and assess fliers identified by the filter, compare multiple sources of bathymetry data, and perform interactive editing. Survey analysis with SABER provides the required file lists and time windows, generates tracklines, processes all navigation data, and applies any necessary correctors as well as automatic ping and beam flag filtering.

The Area-Based Editor replaces line-by-line interactive editing, allowing operators to view and edit all data in an area simultaneously, directly retaining those edits in the full-resolution data files. By dividing large survey areas into sub-areas, SABER can systematically edit, filter, and smooth position data while recalculating depth data for different sound velocity profiles, and recalculating multibeam alignment calibrations for roll/pitch/azimuth offsets, and transducer and antenna mounting positions. SABER data products include volumetric reports for channel analysis; plots of final contours, tracklines and coverage; and junction analysis reports, smooth sheets and profile plots.

SAIC has successfully used ISS-2000 and SABER to conduct surveys for NOAA, the Naval Oceanographic Office (NAVOCEANO), the US Army Corps of Engineers, the University of New Hampshire, and various commercial clients worldwide. SAIC's MSTD works closely with clients to determine appropriate solutions for their survey system needs, and adapts ISS-2000 and SABER for their specific applications.

Qinetiq
Qinetiq, Europe's largest science and technology research organization, launched its seabed mapping software, Classiphi, in 2002. Classiphi, for the first time, marries automated, reliable and fast sidescan interpretation to a flexible and intuitive geographical information system (GIS) with multiple sensor fusion.

Classiphi operates in a significantly different manner to traditional acoustic ground discrimination systems (AGDS). AGDS relies on interpretation of the acoustic signal returned by an echosounder. The structure of the return is used to infer changes in the bottom type.

Invariably, AGDS techniques require regular ground truthing and suffer from the distinctly linear nature of the echosounders used to produce the results.

Classiphi operates in a manner much more similar to the process that a geophysicist or marine scientist will use to create a classification map of the seabed. A trained scientist can tell subtle differences in different types of rock, sand, gravel, and coral, and can use this information to delineate areas of differing texture. This manual process is, however, time-consuming and costly.

Using the trained eye of the scientist, however, Classiphi can be educated as to the different types of texture that are required to be mapped. The process is as simple and intuitive as "join the dots."

Once the results on a short strip of data have been approved, Classiphi will automatically continue to interpret the remaining sonar data on a pixel by pixel area basis.

In this way, a complete record with 100 percent area coverage can be rapidly created. It takes only five to seven hours to process one square mile of survey data, georeferenced at 25cm and with seven textures classified to 1m, on a typical PC. This constitutes a saving of around five days over manual interpretation methods. The charts produced in this short timescale from raw sonar data includes sonar mosaics, texture sheets, area summaries and vector polygon outlines of texture and area.

The UK Naval community's desire to reduce the time taken by the often subjective and paper-based, manual effort of sidescan interpretation for route survey was the root of Qinetiq developing automated interpretation. When UK Directorate of Naval Surveying, Oceanography & Meteorology acquired the two survey vessels, HMS Echo and HMS Enterprise, Qinetiq produced an automated system based on existing feature tracking and classification algorithms.

This lead the company to develop Classiphi, having recognized the need for a dependable and fast classification system for habitat mapping, route survey, exploration and offshore installation planning. Subsequently, Classiphi can handle a range of sensors, including multibeam echosounder, interferometric sonar and LIDAR, as well as multiple data fusion routes in the GIS.

Classiphi's processing can be carried out offline in a batch mode and the results rapidly manipulated in its own GIS. The GIS offers flexible integration paths to ensure the best end use of the surveyor's data. Added to this, the suite of sonar target databasing, chart production toolset and multibeam echo sounder processing ensures that Classiphi is a one package solution - from raw data in to chart product out.

Nortek
A European military contractor has developed a system for mine hunting based on a powerful ROV that runs ahead of the ship at a distance of a few hundred meters, tracking targets as it goes. In mine disposal configuration it is equipped with a relocation sonar and mine disposal charge. To measure the speed and direction, the vehicle was fitted with a new generation Nortek Aquadopp current meter developed specifically to get accurate readings at one-second intervals.

Traditionally, speed through water is measured using mechanical or electro-magnetic single-point current meters. These sensors have major disadvantages because they are protruding and measure the velocity of the water right where the probe is located. A protruding probe is considered to be a disadvantage because the sensor can be damaged if the ROV hits the bottom or a solid object, and also because it is important for the overall drag coefficient that the ROV be streamlined.

The issue of the measurement area is even more of a problem because there is a flow field generated in the vicinity of a fast moving ROV. Conventional current meters will thus underestimate the actual ROV speed unless they are placed on long protruding arms.

The Aquadopp current meter from Nortek eliminates these problems. Similar to other Doppler Velocity Logs (DVL) the Aquadopp uses the Doppler principle to measure the velocity of the water. Ultrasonic pulses at 2MHz frequency are transmitted from the sensor along three narrow acoustic beams. When these pulses hit small particles in the water, a portion of the energy is reflected back to the sensor, and the echo is frequency-shifted (Doppler shift).

The Aquadopp in ROV configuration uses a right-angle sensor head and can be mounted flush with the ROV without any protruding parts. The sensor is buoyant in water so it does not steal from the ROV ballast. The Aquadopp measuring volume can be set as far as 5m away from the ROV, which means that the measured velocity is unaffected by ROV itself. Finally, the Aquadopp price tag is only about one-third of the price of comparable bottom tracking DVLs.