Bathymetry

Bathymetric surveys

Bathymetric Surveys

To carry out bathymetric surveys performed first a detailed planning and documentation are required. Then to carry out the task, we use the following devices, installed on the boat hydrographic CIS:
 

  • Multibeam bathymetric probe
  • Inteferometric Probe
  • Tools for data management
  • Differential GPS gyro function
  • Motion sensor
  • Sound velocity profiler

 

Bathymetric surveys overlays on orthophoto

 

 
Multibeam bathymetric probe

This probe is designed to produce multibeam bathymetric maps digital spacious study areas and to depths of 200 m. Coverage with each pass can cover up to 300 m wide. The transducers emit at 250 kHz frequency and rate of 10 pulses per second, which generates a speed capture probe points of about 3,000 per second. The transverse resolution is 4.5 cm, far exceeding the specifications of "Standards for Surveys Hidrographic" (1998) marked by the IHO (International Hydrographic Organization).

 

The multibeam team can ensure 100% coverage in the survey area, up to 200 points per square meter probe. The delivery format is multiple, from ASCII, TXT, XYZ, bent low surfer, terramoder, 3D, Microstation, Autocad ... on demand.
 

 

The equipment consists of a workstation with a Pentium III. Installed programs allow: the calibration of equipment, data acquisition and real-time generation of mosaic partial real-time correction data and generates the same postprocessing digital bathymetric model 3D and classic curved isobaths. This equipment is connected to a motion sensor-corrector, a gyro and a differential GPS, in line with the central processor that corrects in real time the signal from the two ceramic transducers.
 

 

 

 

 

 

 

 

 

 

 

3D map extracted from the sonar and map on orthophoto overlay

 

In parallel, another device has multi-beam probe, the R2sonic, with a bandwidth of 200 kHz to 400 kHz.

 

                                       

 

 

 

 

 

 

Images from the device R2sonic

 

Features of multibeam bathymetric probe GeoSwath 250:

  • Sound frequency: 250 kHz
  • Maximum depth: 100 m
  • Sweeping path max.: 300 meters
  • Horizontal resolution: 1.5 cm.
  • Scan Rate: 10 pulses / sec.
  • Other features:
    • Dynamic correction of wave compensator, gyrocompass, probe speed of sound and GPSD
    • Real-time acquisition of bathymetry and sidescan sonar
    • Generation of 3D digital maps of the terrain
    • A comprehensive tool for data acquisition and subsequent processing in the study and bathymetric mapping.

Features of multibeam bathymetric probe R2sonic 2024:

  • Banda ancha de 200kHz a 400KHz
  • Procesador / controlador interno
  • Bajo consumo, pequeño peso y volumen
  • Módulos interconectados
  • 60kHz Wideband Signal Processing
  • Focused 0.5° Beam Width
  • Selectable Frequencies 200-400kHz
  • Selectable Swath Sector 10° to 160°
  • System Range to 500m
  • Embedded Processor/Controller
  • Equiangular or Equidistant Beams
  • Roll Stabilization
  • Rotate Swath Sector

Download specifications R2sonic 2024 (PDF)

Tools for data management


 

The data analysis program can display all of the information with a clear geographic component. This will be from tabular data "x, y, z" to the multiple representations. It is also possible the calculation of volumes, surfaces, profiling, etc..

 

 

Differential GPS gyro function

 

 

 

 

 

The differential GPS gyro can take the boat's position with centimeter accuracy.

 

 

 

 

 

 

 

 

Motion sensor

In bathymetric work does not make sense to use a GPS sensor and a centimeter if not then have a good swell compensator to eliminate the errors of wave height (vertical error) or because the position lateral movements of the ship (pitch and roll). In this small graph shows this common type of errors affecting the accuracy of the probe and positioning.

 

Features swell compensator TSS DMS 05:

  • Specifically designed for Multibeam puroposes
  • Accuracy of 0.025 ° for pitch / roll. Resolution 1 cm
  • Digital output data wave, pitch and roll at 200 Hz
  • Speed ​​input and gyroscopic
  • Immune to acceleration in the turns

 

Sound velocity profiler


The calibration studies bathymetry is synonymous with quality. Our work protocols involve making two profiles of the velocity of sound in water: one at the beginning and at the end of each workday. In addition a sensor SVP analyzes changes in surface continuously. With all that this variable is averaged as much relevance does the accuracy of the final results.