Kongsberg EK80 Instruction Manual
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Kongsberg EK80 Instruction Manual

Kongsberg EK80 Instruction Manual

Wideband scientific echo sounder calibration
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Instruction Manual
EK80 Echo Sounder Calibration
Wideband Scientific Echo Sounder
kongsberg.com/ek80
110-0001152/B

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Summary of Contents for Kongsberg EK80

  • Page 1 Instruction Manual EK80 Echo Sounder Calibration Wideband Scientific Echo Sounder kongsberg.com/ek80 110-0001152/B...
  • Page 3 EK80 system fitted with relevant hardware for echo sounder/target strength (TS) measurements. For more information about the practical use of the EK80 system, as well as detailed information about the functions and dialog boxes provided, refer to the Reference Manual and/or the context sensitive On-line help.

  • Page 4: Document Information

    Kongsberg Discovery disclaims any responsibility for damage or injury caused by improper installation, use or maintenance of the equipment. Disclaimer Kongsberg Discovery AS endeavours to ensure that all information in this document is correct and fairly stated, but does not accept liability for any errors or omissions. Support information If you require maintenance or repair, contact your local dealer.

  • Page 5: Table Of Contents

    User manual for Echo sounder calibration Table of contents ABOUT THIS MANUAL..................5 INTRODUCTION....................7 Echo sounder calibration....................7 Echo sounder calibration parameters................9 Factors affecting the calibration results................9 Calibration spheres......................10 TS response curves......................12 Support information....................... 12 ECHO SOUNDER CALIBRATION..............13 Preparing Echo sounder calibration................13 Recording raw data......................
  • Page 6 Kongsberg EK80 Edit/Add Sphere dialog box................. 72 Calibration Description dialog box...............74 Single Target Detection dialog box..............75 References......................81 INDEX........................ 82 110-0001152/B...

  • Page 7: About This Manual

    • EK80 Target audience Calibrating the EK80 system ensures that the accuracy is obtained. Calibration must be taken seriously. To achieve the best results, the calibration must be planned and done carefully. Due to the nature of the descriptions and the level of detail provided by this publication, it is well suited for those who are - or wish to be - expert users.
  • Page 8 Simrad logo are either registered trademarks, or ® ® ® trademarks of Kongsberg Discovery AS in Norway and other countries. Windows is a registered trademark of Microsoft Corporation in the United States and ® other countries. We want your feedback We always want to improve our products.

  • Page 9: Introduction

    Kongsberg Discovery and various research institutes are striving to improve and develop calibration methods. The calibration recommendations are therefore subject to change. Please, refer to the latest recommendations for calibrating the EK80 system. 110-0001152/B...
  • Page 10 Calibration using several spheres - merging calibration results Various calibration spheres can be used to calibrate the EK80 system. The material and size of the sphere will make the TS measurements different for each sphere. It is possible to combine the calibration results of several spheres. Multiple spheres can be used to cover “gaps”...

  • Page 11: Echo Sounder Calibration Parameters

    • A change of transducers or transceivers. • A change in the calibration spheres or their suspension. In addition, an update to the EK80 software version may require a new calibration. Refer to the software release note for details. Factors affecting the calibration results The EK80 system is a highly sensitive acoustic instrument and measurements can be affected by many factors.

  • Page 12: Calibration Spheres

    Kongsberg EK80 User manual for Echo sounder calibration entered into the EK80 system prior to calibration. The parameters must be valid for the water column from the transducer to the calibration sphere and a valid sound velocity at the transducer face must be entered.
  • Page 13 A 25 mm Tungsten sphere tied in a netbag with three suspension lines. Sphere can be supplied by Kongsberg Discovery. Kongsberg Discovery offers two spheres for LFM calibration: • WC38.1 Tungsten sphere with 38.1 mm diameter, tied in a netbag and with three suspension lines.

  • Page 14: Ts Response Curves

    WC38.1 and the red line is WC25. Support information If you need technical support for your EK80, you must contact your local dealer, or one of our support offices. A list of all our offices and dealers is available on our website.

  • Page 15: Echo Sounder Calibration

    Calibration is the best way to check and verify both the operational performance of the EK80 and the quality of the installation. In order to calibrate the EK80 system, a reference target (calibration sphere) with known target strength (TS) is lowered into the sound beam.
  • Page 16 • Reconnecting an already calibrated transducer and transceiver pair, the old calibration data may be retrieved and used. A new calibration is not required. A new calibration may also be required if the EK80 software is updated. Refer to the software release note.
  • Page 17 Echo sounder calibration The information provided by the calibration is entered into the EK80 software as operational parameters. This is done automatically. We strongly recommend that calibration surveys are done at regular intervals. As a minimum, calibration must be done prior to each survey.

  • Page 18: Recording Raw Data

    Lower the sphere into the beam at the specified depth. Verify that the echoes are clearly detected. Recording raw data Use the raw data recording functionality provided by the EK80 system to save echo data using the format. You can save the data to the hard disk, or onto an *.raw...

  • Page 19: Echo Sounder Calibration For Split-Beam

    About this task When you calibrate the EK80 system for TS measurements with "live data", it is very important that you choose the correct channel, and that all the other channels are switched to Passive mode. You must do this before you start the calibration process.
  • Page 20 Kongsberg EK80 User manual for Echo sounder calibration Procedure In the dialog box, select Output File Setup On the page, define the relevant file and folder properties. File Setup Note We strongly recommended that you always store the raw data from the calibration.
  • Page 21 Start • During the data import, use the three winches to move the sphere inside the sound beam. To successfully calibrate the EK80 system you need to place a number of target detections in each slice. The echoes must be distributed within the entire beam cross-section. In order to do this, the target sphere must be physically moved inside the beam during the calibration process.

  • Page 22: Cleaning The Collected Ts Data (Split-Beam Transducers)

    "clean" the echo data Calibration Wizard before you process it to calibrate the EK80. When the processing is finished, you can save the results, and update the calibration data used by the EK80. Before you begin In order to process echo data for calibration, you must have imported and saved valid echo data from a relevant calibration target (sphere) inside the beam.

  • Page 23: Echo Sounder Calibration For Single-Beam

    About this task When you calibrate the EK80 system for TS measurements with "live data", it is very important that you choose the correct channel, and that all the other channels are switched to Passive mode. You must do this before you start the calibration process.
  • Page 24 Kongsberg EK80 User manual for Echo sounder calibration Use the file name to identify the your physical location, the frequency used, which calibration sphere that is used, and the pulse form. Information about the data and time of the recording is automatically added to the file name.

  • Page 25: Cleaning The Collected Ts Data (Single-Beam Transducers)

    "clean" the echo data Calibration Wizard before you process it to calibrate the EK80. When the processing is finished, you can save the results, and update the calibration data used by the EK80. Before you begin In order to process echo data for calibration, you must have imported and saved valid echo data from a relevant calibration target (sphere) inside the beam.

  • Page 26: Choosing Which Raw Data File(S) To Replay

    Kongsberg EK80 User manual for Echo sounder calibration Click on the top of the column to sort the table values by this TS Comp parameter. Remove the hits that differ as high or weak echoes. Repeat the procedure for the...

  • Page 27: Modifying, Adding And Removing A Frequency Band

    TS. You can remove one or more frequency bands from the calibration processing. This is done by defining "stop bands". The EK80 is not calibrated for the frequencies inside the chosen frequency band.

  • Page 28: Merging/Replacing Calibration Results For Multiple Spheres

    Merging/replacing calibration results for multiple spheres Prior to calibration, you must check that your EK80 is fully functional. Before you begin In order to merge or replace calibration results you need to do one of the following: •...
  • Page 29 Echo sounder calibration backscatter from the sphere. The gaps are determined by the inhibited bands selected for a given sphere during the calibration process. Using multiple spheres allows you to fill in the gaps from one sphere with the backscatter values from another. When merging spheres, the most recent sphere calibration values will be used, and gaps in the frequency response will be filled with previous sphere calibration data.

  • Page 30: Functions And Dialog Boxes

    Prerequisites can only be opened from within the calibration process. Calibration Wizard How to open To open the , place the EK80 system in either Normal or Replay mode, Calibration Wizard then select on the menu. Calibration...
  • Page 31 Select this option when you have a previous XML file with calibration data available for reprocessing. Adding a new transducer to a previously calibrated EK80 system requires a calibration of the new channel. Moving an already calibrated transducer from one transceiver to another requires a new calibration of the newly connected transducer and transceiver.

  • Page 32: Calibration Wizard Dialog Box #2 (Select Channel)

    Prerequisites can only be opened from within the calibration process. Calibration Wizard Calibration can only be started with the EK80 system in either Normal or Replay mode. How to open To open the , place the EK80 system in either Normal or Replay mode,...

  • Page 33: Calibration Wizard Dialog Box #3 (Select Sphere)

    Prerequisites can only be opened from within the calibration process. Calibration Wizard Calibration can only be started with the EK80 system in either Normal or Replay mode. How to open To open the , place the EK80 system in either Normal or Replay mode,...
  • Page 34 Copper (Cu). The former is also referred to as Wolfram carbide (Wo-Co). "Co" is short for Cobalt, which is used as binder in the sphere. Note Kongsberg Discovery can supply a variety of copper and tungsten calibration spheres dedicated for different operational frequencies. Contact your dealer or the Kongsberg support organization for advice.
  • Page 35 You can remove one or more frequency bands from the calibration processing. This is done by defining "stop bands". The EK80 is not calibrated for the frequencies inside the chosen frequency band. The software in the EK80 will instead interpolate calibration values.
  • Page 36 Kongsberg EK80 User manual for Echo sounder calibration • Select , then select a band on the curve to delete it from the Remove Inhibited Band TS/Frequency curve. As an alternative, you can do the entire calibration one more time using another sphere.

  • Page 37: Calibration Wizard Dialog Box #4 (Import Data): Split-Beam Transducer

    Prerequisites can only be opened from within the calibration process. Calibration Wizard Calibration can only be started with the EK80 system in either Normal or Replay mode. How to open To open the , place the EK80 system in either Normal or Replay mode,...
  • Page 38 Kongsberg EK80 User manual for Echo sounder calibration Description The fourth page of the dialog box is divided into three fields. Calibration Wizard To change the size of the individual field, click and drag the field borders. You can also increase the size of the dialog box. To make the dialog box cover the entire screen, double-click the title bar.
  • Page 39 Functions and dialog boxes Target Position field The left side of the Target Position field shows all the individual echoes that are imported into the calibration program. All echoes are placed inside a circle to reflect their locations in the beam. The echoes are compensated for their positions within the beam, so that echoes from the outer...
  • Page 40 Kongsberg EK80 User manual for Echo sounder calibration The right side of the field shows the calibration layer that is automatically created once the calibration starts. You can see how each individual echo is received within the calibration layer. This...
  • Page 41 "slices". A split- beam transducer has three or four sectors. The circular cross-section is split into several slices. To successfully calibrate the EK80 system you need to place a number of target detections in each slice. The echoes must be distributed within the entire beam cross-section.
  • Page 42 Kongsberg EK80 User manual for Echo sounder calibration page also offers curves to monitor the gain, the beamwidth and the beam offset as a function of the operating frequency. TS Data page shows you all echoes that are detected and accepted. The TS Data list will expand as you collect data.The page consists of a table with different...
  • Page 43 Functions and dialog boxes • : This column shows the mechanical angle in the athwartship Athwartship direction to the hit in degrees. Calibration layer When the calibration process is started, a dedicated layer is automatically created. If a strong and easily detected echo from the calibration sphere is shown in the echogram, the layer will position its borders over and under the target.
  • Page 44 Kongsberg EK80 User manual for Echo sounder calibration Details Start/Stop/Continue This button starts (and stops) the import of echo data to the calibration program. While the import is active, each echo is drawn in the Target Position field. When you are calibrating with "live data", keep importing echoes until these are evenly distributed inside the circular beam.
  • Page 45 Functions and dialog boxes Minimum/Maximum Depth These settings are located on the page in the Numerical field. Use these General parameters to adjust the depth limits of the calibration layer, thus creating a "depth window". Echoes from objects outside the defined limits are not imported.

  • Page 46: Calibration Wizard Dialog Box #4 (Import Data): Single-Beam Transducer

    Prerequisites can only be opened from within the calibration process. Calibration Wizard Calibration can only be started with the EK80 system in either Normal or Replay mode. How to open To open the , place the EK80 system in either Normal or Replay mode,...
  • Page 47 Functions and dialog boxes The Numerical field provides several tabbed pages. The page shows the General common data and parameters for the system used during calibration. Transceiver parameters common to all beams The page displays numerical Channel Data parameters related to the transceiver channel that was used to record the echo data.
  • Page 48 Kongsberg EK80 User manual for Echo sounder calibration The right side of the field shows the calibration layer that is automatically created once the calibration starts. You can see how each individual echo is received within the calibration layer. This...
  • Page 49 Functions and dialog boxes TS Histogram plot presents a histogram with the echoes from the calibration TS Histogram sphere. The histogram provides a visual indication of the percentage of echoes located on the decibel scale within the chosen interval. TS [dB] / Range / Hit Number plot redraws the information shown on the TS [dB] / Range / Hit Number with hits within the range window.
  • Page 50 Kongsberg EK80 User manual for Echo sounder calibration TS Data page shows you all echoes that are detected and accepted. The TS Data list will expand as you collect data.The page consists of a table with different columns: • : This column shows the sequential number of the hit.
  • Page 51 Functions and dialog boxes Calibration layer When the calibration process is started, a dedicated layer is automatically created. If a strong and easily detected echo from the calibration sphere is shown in the echogram, the layer will position its borders over and under the target. You must lower the sphere to a known depth.
  • Page 52 Kongsberg EK80 User manual for Echo sounder calibration Details Start/Stop/Continue This button starts (and stops) the import of echo data to the calibration program. While the import is active, each echo is drawn in the Target Position field. When you are calibrating with "live data", keep importing echoes until these are evenly distributed inside the circular beam.
  • Page 53 Functions and dialog boxes Minimum/Maximum Depth These settings are located on the page in the Numerical field. Use these General parameters to adjust the depth limits of the calibration layer, thus creating a "depth window". Echoes from objects outside the defined limits are not imported.

  • Page 54: Calibration Wizard Dialog Box #5 (Process Data): Split-Beam Transducer

    The fifth page in the allows you to manually "clean" the echo data Calibration Wizard before you process it to calibrate the EK80. When the processing is finished, you can save the results, and update the calibration data used by the EK80. Prerequisites can only be opened from within the calibration process.
  • Page 55 Functions and dialog boxes The left side of the Target Position field shows all the individual echoes that are imported into the calibration program. All echoes are placed inside a circle to reflect their locations in the beam. The right side of the field shows the calibration layer that is automatically created once the calibration starts.
  • Page 56 Kongsberg EK80 User manual for Echo sounder calibration • In FM calibrations, additional circles (dotted lines) are added to signify the upper and lower frequencies. The solid line indicates the nominal frequency. If you select a single echo on the...
  • Page 57 Functions and dialog boxes • For CW: The purple line reflects the bandwidth of the current "ping". The bandwidth is inverse proportional with the pulse length. For FM: The purple line reflects the received echo of the current "ping". The curve reflects the TS value as a function of the frequency.
  • Page 58 Kongsberg EK80 User manual for Echo sounder calibration TS Data page page allows you to suspend individual echoes from the calibration TS Data processing. The page consists of a table with different columns: • : Select the check box in this column to exclude the hit from the Suspended calibration.
  • Page 59 Functions and dialog boxes Results page page displays the numerical parameters that are created by the Results calibration processing. Different results are offered for CW and FM calibration. • After an FM calibration, the results are provided as graphs for beam offset, beam width and gain as a function of the frequency.
  • Page 60 Kongsberg EK80 User manual for Echo sounder calibration Error analysis page displays all the individual echoes that are imported into Error Analysis the calibration program. 110-0001152/B...
  • Page 61 Functions and dialog boxes The error analysis is based on an estimated TS value from your calibration sphere. This estimate is based on the sphere parameters, the depth and the operational frequency. Each echo is shown using a colour to indicate the error of the hit. This allows you to locate echoes that are stronger or weaker than the estimated TS.
  • Page 62 Kongsberg EK80 User manual for Echo sounder calibration You can also select a single echo in the Target Position field. The corresponding row in list will be shown with a grey background colour. TS Data To remove a single echo from the calibration processing, select...

  • Page 63: Calibration Wizard Dialog Box #5 (Process Data): Single-Beam Transducer

    The fifth page in the allows you to manually "clean" the echo data Calibration Wizard before you process it to calibrate the EK80. When the processing is finished, you can save the results, and update the calibration data used by the EK80. Prerequisites can only be opened from within the calibration process.
  • Page 64 Kongsberg EK80 User manual for Echo sounder calibration Note TS measurements can be single or split beam. For combi transducers, make sure that you know which channel is used for single beam and which one is used for split beam.
  • Page 65 Functions and dialog boxes • The page displays the numerical parameters that are created by the Results calibration processing. Target Position field The left side of the Target Position field shows all the individual echoes that are imported into the calibration program.
  • Page 66 Kongsberg EK80 User manual for Echo sounder calibration The Frequency/Target Strength field shows the relationship between the frequency and the TS for the sphere in current use. • The blue line represents the theoretical TS. • The two brown lines reflect the limits that were defined by the...
  • Page 67 Functions and dialog boxes TS Data page page allows you to suspend individual echoes from the calibration TS Data processing. The page consists of a table with different columns: • : Select the check box in this column to exclude the hit from the Suspended calibration.
  • Page 68 Kongsberg EK80 User manual for Echo sounder calibration To find the echoes you want to suspend, select the top row of each column to sort the content. You will typically suspend those hits that are outliers in most of the columns. You can also select a single echo in the Target Position field. The corresponding row in the will be shown with a grey background.
  • Page 69 Functions and dialog boxes Note The S correction is only calculated for CW transmissions. • When calibrating a Wide Band Transceiver (WBT), the effective pulse duration is calculated and used to determine the S correction. This will normally result in a S correction of around 0 dB.
  • Page 70 Kongsberg EK80 User manual for Echo sounder calibration To remove a single echo from the calibration processing, select in the left Suspended column. The chosen echo changes to white colour in the Target Position field. To select multiple hits, select one ping, keep the...
  • Page 71 Functions and dialog boxes • Use to remove all old calibration results. This allows you to only use Replace the latest parameters for the relevant channel. In FM, one single set of calibration values is saved, and this set covers all pulse durations.

  • Page 72: Secondary Functions And Dialog Boxes

    Replay File Description A key function of the EK80 system is its ability to record echo data. You can save the data to the hard disk, or onto an external storage device. The dialog box Replay File allows you to choose which file(s) to be used for playback.
  • Page 73 Loop Select if you want the EK80 system to play back all the files in an endless Loop loop. The replay will run until you stop it in the replay bar, or choose a different operating mode.

  • Page 74: Edit/Add Sphere Dialog Box

    Calibration Wizard dialog box. The can only be opened from within the calibration Calibration Wizard process. Calibration can only be started with the EK80 system in either Normal or Replay mode. How to open To open the , place the EK80 system in either Normal or Replay mode,...
  • Page 75 Type the name you wish to use to identify the calibration sphere. Note that while editing the sphere parameters, you are not permitted to change its name. If you do not have a computer keyboard connected to your EK80 system, select button to open an on-screen keyboard.

  • Page 76: Calibration Description Dialog Box

    How to open dialog box is opened from the third and fourth pages in the Calibration Description Calibration Wizard To open the , place the EK80 system in either Normal or Replay mode, Calibration Wizard then select on the menu.

  • Page 77: Single Target Detection Dialog Box

    How to open dialog box can be opened from the third and fourth pages Single Target Detection in the wizard. Calibration can only be started with the EK80 system in either Calibration Normal or Replay mode. 110-0001152/B...
  • Page 78 Kongsberg EK80 User manual for Echo sounder calibration Description A dedicated calibration layer is created to isolate the echo from the sphere. Still, several other echoes may be present within the same layer, for example due to fish. In order to detect the sphere correctly, these parameters must be defined to suit its characteristics.
  • Page 79 Maximum Gain Compensation This setting applies to both CW and FM operation. Not all single targets are located in the centre of the beam. Targets located off centre will offer weaker echoes due to the beam properties. The EK80 system 110-0001152/B...
  • Page 80 Kongsberg EK80 User manual for Echo sounder calibration automatically compensates for this using a mathematical model, and you can manually control the effect of this algorithm by defining a maximum gain value. Using the 3 dB setting all echoes from within the nominal beam width of the transducer will be accepted.
  • Page 81 In this context, the term channel is used as a common term to identify the combination of transceiver, transducer and operating frequency. Apply to All Layers Check this box to apply the current setting to all the depth layers on your EK80 system. Related dialog boxes...
  • Page 82 Kongsberg EK80 110-0001152/B...

  • Page 83: References

    References References The following papers have been used as references in this manual. • Bodholt, H. (2002). The effect of water on temperature and salinity on echo sounder measurements. ICES paper no. 123. ICES. • Khodabandeloo, B. O. (2020). Nonlinear crosstalk in broadband multi-channel echosounders.

  • Page 84: Index

    Kongsberg EK80 Index density (continued) calibration sphere ........74 about ............description ............. document downloads ........5 Add/Edit Sphere dialog box ......73 online information ........5 Calibration Wizard dialog box #1 ..... 28 registered trademarks ........5 Calibration Wizard dialog box #3 .... 32, 36, 44 software license ..........
  • Page 85 ............ Reprocess previous calibration data support ...........12 Calibration Wizard dialog box #1 ..... 29 technical support ........12 Single Target Detection dialog box ......Kongsberg Discovery description ..........75 support ...........12 software license ..........about ............5 software version ..........
  • Page 86 Kongsberg EK80 website (continued) website (continued) document downloads ........5 online information ........5 110-0001152/B...
  • Page 88 ©2024 Kongsberg Discovery ISBN N/A...

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