3 Essential Hydrographic Survey Equipment

The top three fundamental hydrographic survey devices are outlined below.

1. Echo sounder

Bathymetry: the science of calculating water depth. No matter whether you are surveying, dredging or managing underwater operations, correct bathymetric data is critical, be it total water depth or the position of particular equipment within the water column.

Digital signal processing methods that use fuzzy logic are on offer to choose from. These echosounders will pick out and lock onto the authentic echo, while automatic power and gain management means that false echoes are reduced and exact readings can be produced in water depths as shallow as 30cm. Being a stand alone altimeter, this device is ideal for integration into bathymetry equipment. Combining the technology with integral GPS receiver and on board data collection presents echo sounders with the added benefits of maximum versatility and minimal deployment time.

Echosounders, both single and multi-beam need sound velocity records to effectively generate depth measurements. If simple, small boat echo sounding is necessary with single or dual frequency transducers and interface of external parameters with GPS reference then a single beam echosounder is appropriate.

The MIDAS Surveyor has been created to offer a reduced price tag product for modest scale hydrographic surveys. The device is supplied with a 210kHz transducer as normal, and uses sophisticated digital signal processing procedures to ensure high accuracy and reliable bottom tracking. With a built in SBAS enabled DGPS receiver, the MIDAS Surveyor will log location and depth records for more than 30 hours, together with undertaking on-line correction utilizing external heave and tide data inputs. Alternatives include an added 33kHz transducer, or high accuracy 16 channel DGPS receiver.

2. Sound Velocity Profiler

Sound Velocity Profilers are these days on offer on the market that can offer the following qualities

a. Genuine Accuracy of ±0.02m/s (Total Error Budget)

b. Precision (peak to peak noise) of ±0.002m/s

c. Operating range of 1375m/s to 1900m/s (covering all environments from fresh water to the Dead Sea and the Marianas Trench)

d. Data rates up to 60Hz (instrument dependent)

One particular profiler is the miniSVP, a new low cost version, developed to generate the most effective SV readings in the world readily available to everyone. Featuring the unique and acclaimed "time of flight" SV sensor, the miniSVP is offered in either 500m rated acetal or 6000m rated titanium versions. A single C cell and large Flash memory enable hundreds of profiles to be recorded, and the pre-set profiling patterns let it to be setup and deployed quickly and easily.

3. Water Level Recorder

Tidal gauges provide possibly the most fundamental of all marine readings - Precise tidal data. This is essential for Port & Harbour Operations, Dredging, Surveying, equipment deployments, and many other applications.

Features include:-

a. logging of tidal data for historical purposes;

b. ability to provide real time information,

c. transmission of data over a variety of telemetry links,

d. network capabilities,

e. fixed displays or access through web or local intranet,

f. seabed fixing or in-line mooring.

The TideMaster is a small, cost effective Water Level Recorder, specifically formulated for applications where the end user requires an exact record of water height, but with the added option of meteorological information via an ultrasonic wind speed and direction sensor. Appropriate for use in fresh or salt water, the TideMaster can be deployed for up to 1 year, dependant on the sampling rate, with instrument set up and data retrieval via an optional display panel or using the PC application provided. Additionally, the device can be provided with radio modules for real time data transmission.