Simrad echosounders data files

BI500 data files (-ping, -vlog, -data, -info, -work)

EK15 data files

EK80 data files (.raw, .bot, .xyz)

EK500 data logged with DFO/NHP/DAT CH1 logging software (.hac)

EK500 telegrams logged with Simrad ER60 software (.dg)

Ex60 data files logged with Echolog 60 (.ek60, .ek6)

Ex60 raw data files (.raw/.out/.bot)

Ex70 data files

Ex500 and Ex60 data logged with Echolog 500 (.ek5)

EY500 data, and EK500 data logged with Simrad EP500 software (.dgn)

ME70 raw data files (.raw)

MS70 raw data files (.raw)

SM2000 FR data files (.raw/.bfm/.bmf and .nnn)

SM2000 FR data files logged with Echolog SM (.sm2000)

SH80 data files (.dat, .dzt)

SH90 data files

SP70 data files (.dat, .dzt)

SU90 data files (.raw)

SX90 data files

SC90 data files

Omnisonar netCDF (.nc)

Notes:

Simrad is a subsidiary of Kongsberg. See also Kongsberg data files.
Echoview supports NME0 and NME1 data recorded with Simrad/Kongsberg echosounder data files.
Some Simrad fles may be verified by Echocheck.

BI500 data files (-ping, -vlog, -data, -info, -work)

These are Echosounder data files that have been processed into the format used by the Simrad BI500 software. The files have no extensions, but can be recognized by their suffixes. There are up to five files for each dataset. Of these, –ping and –data must be present in the same folder in order to be used by Echoview (the rest are optional). Each set of files contains the data collected over exactly five nautical miles.

Note: These files store numeric values internally in big-endian format, which is different to the little-endian format used natively by Intel processors. Echoview makes the appropriate translations as required.

BI500 files use a naming convention like the following:

N090-S001-S1997001-F037879-T01-D19970208-T043746-Ping

where the components are:

- a nation code (Nnnn)
- a ship code (Snnn)
- a survey code (Snnnnnnn)
- the transceiver frequency (Fnnnnnn)
- the transceiver number (Tnn)
- the date (Dyyyymmdd)
- the time (Thhmmss)
- the file type (ping, vlog, data, info or work)

Echoview requires this format to be followed for the transceiver number, date and time parts of the filename.

Echoview extracts the following information from each file:

Value	Description
-ping	All ping data, including its start and stop range and sample count and GPS position but not including Sv values, single target detection or vessel log information
-data	Sv values and single target detections
-info	Used to determine the little- or big-endian status of the data. Big-endian will be assumed.
-vlog	Vessel logs
-work	Line and region definitions. This information is read only once, when the information within BI500 -work files is imported to Echoview, after which the line and region definitions are stored in the EV file. Subsequent changes to the –work file will have no effect. Use File menu > Import.
-snap	Echoview does not read –snap file, but they are of the same format as –work files. If renamed to –work, Echoview will extract line and region definitions from the –snap file

EY500 data, and EK500 data logged with Simrad EP500 software (.dgn)

Internally this format consists of the binary telegrams produced by the Echosounder. Each telegram is preceded by a four-byte number stored in little-endian format. This number contains the length in bytes of the following telegram.

These files are named in the format: mmddhhnn.DGy, where "mm" is the month, "dd" s the day, "hh" is the hour, "nn" is the minute and "y" is last digit of the year.

This file naming convention has a number of inherent limitations:

If the file does not contain any "LL" or "VL" type telegrams then Echoview cannot positively determine the year of logging. Echoview will try to determine the year by adding 199 to the last digit (n) in the file name, e.g. 11211256.DG3 would be assumed to have been logged in 1993, but may have been logged in 2003.
Echoview will not be able to correctly order the files in a fileset that extend over decade boundaries, for example between 31 December 1999 and 1 January 2000.

To overcome these problems you can rename the files using the following format: "mmddhhnn.yyyy.DGY", where "mm" is the month, "dd" s the day, "hh" is the hour, "nn" is the minute, "yyyy" is the year, and "Y" is last digit of the year. Echoview will read "yyyy" and correctly determine the logging year.

The EP500 software can also produce files with a .DTn extension, which contains compressed and thresholded data corresponding to a .DGn file. DTn files use a Simrad proprietary format, and they cannot be read by Echoview.

Notes:

At this time Echoview does not directly support data files that have been created with multiplexed transducers, however a utility to translate such files into a format that Echoview can support is available on request from Echoview support. Currently, this utility program supports files that contain up to four multiplexed transducers.

Ex500 and Ex60 data logged with Echolog 500 (.ek5)

These files contain EK500 data telegrams output by an Ex60 or Ex500 on its Ethernet port. EK500 telegrams are generally contained within one Ethernet packet, but some telegrams (e.g. sample telegrams) may be split over a number of Ethernet packets. The .ek5 file contains binary Ethernet packets as output by the Simrad echosounder. Each packet is preceded by a two-byte number stored in little-endian format. This number contains the length in bytes of the following telegram.

The EK500 manual contains full details of the EK500 Ethernet telegram formats and should be consulted for interpreting the Ethernet packets recorded within an .ek5 file.

The files are named using the following convention:

"ccyyMMdd-hhmmss.EK5", where "ccyy" is the year, "MM" is the month, "dd" is the day, "hh" is the hour, "mm" is the minute and "ss" is the seconds. Files produced by recent versions of Echolog 500 use this file naming convention.

Early versions of Echolog 500 (Echolog EK) used another file naming convention:

"ccyyMMdd-nnnn.EK5", where "ccyy" is the year, "MM" is the month, "DD" is the day, and "nnnn" is a unique serial number from "0000" to "9999". This convention is supported by all versions of Echoview.

Echoview will also support a third file name format:

"yymmddnn.EK5, where "yy" is the last two digits of the year, "mm" is the month, "dd" is the day and "nn" is a serial number from "00" to "99". In this case "yy" values of 60 to 99 are assumed to represent years from 1960 to 1999 and values from 00 to 59 are assumed to represent years from 2000 to 2059. If this convention is used then Echoview will not correctly handle datasets that extend the century boundary between 31 December 1999 and 1 January 2000. The use of this file name format is not recommended.

Live viewing of EK500 telegrams is supported using Echolog 500.

Notes:

If you are logging B telegrams using ER60 software you should be aware that angular positions are stored with a lower precision in B telegrams (64 steps) than in Ex60 .raw files (128 steps). Furthermore, the ER60 version 2.0.0 encodes B telegrams incorrectly (this is a known bug that Simrad plan to correct with a new release of the ER60 software, please contact Simrad for further information). Echoview Software strongly recommends you do not log B telegrams from an Ex60 echosounder, and use the .raw format instead.
At this time Echoview does not directly support data files that have been created with multiplexed transducers on an Ex500 series echosounder, however a utility to translate such files into a format that Echoview can support is available on request from Echoview support. Currently, this utility program supports files that contain up to four multiplexed transducers.
Echoview ignores PR (Parameter Request) telegrams.
Marker regions are created for EK500 Comment string telegrams.

EK500 data logged with DFO/NHP/DAT CH1 logging software (.hac)

This format is defined by Y. Simrad et al 1997, in Description of the HAC standard format for raw and edited hydroacoustic data, version 1.0, Canadian Technical Report of Fisheries and Aquatic Sciences 2174.

Internally the files consist of a sequence of tuples. While tuple types are defined for both the EK500 (v5.3) and BioSonics 102 echosounders, only the former is supported at this stage.

Please note the following restrictions:

Files must be in the little-endian format.
Only the U32 type pings tuples are supported.
EK500 calibration within Echoview is not supported.

The files should be named in such a way, as an alphabetical sorting of the file names will sort them into date/time order.

Ex60 raw data files (.raw, .out, .bot)

.raw files contain power data written directly by an Ex60. Echoview supports up to 9 transducers in these data files. Echoview also supports heave, pitch and roll data read from the RAW tuple in Ex60 .raw files.

.raw files contain an array of values called "Sa correction", one for each available pulse length. This value represents the correction required to the Sv constant to harmonize the TS and NASC measurements. The Sa correction is determined during the calibration of the echosounder and can be set in Echoview on the Calibration page of the Variable Properties dialog box.

.raw files that were written by a split-beam echosounder will also contain angular position data. The angular data in .raw files has a higher resolution (128 steps) than angular information in B telegrams logged in .dg and .ek5 data files (64 steps).

.raw files also contain NMEA sentences, of which Echoview supports the following subset:

$ECGxx, $GPGxx, $AGRMC, $AGGLL and $INGxx sentences containing GPS fixes
$SDVLW containing vessel log data
$GPHDT, $GPVTG, $INHDT and $INVTG containing heading data
$PSIMP containing depth sensor data
$IIDBS containing depth sensor data
$GPGGA containing altitude data
Furuno $PFEC NMEA sentences containing heading, pitch, roll and heave data

Echoview derives an individual position GPS variable for each GPS NMEA sentence. A (combined) position GPS variable is also derived, and it contains data from all the GPS NMEA sentences.

Transducer metadata

Echoview reads the transducer name from the file TransducerName attribute. Echoview reads and uses the transducer metadata Vertical Transducer Offset, and assigns it to the value for Transducer location Z - vertical offset (m). Consider reviewing of the interaction of Transducer location Z - vertical offset with the Platform Z co-ordinate of the water value and adjust if it is required.

Notes:

Depth sensor data may be read from the Heave field of the ping record. Echoview will provide the depth sensor data as a raw line variable which may be displayed on the echogram.
Sounder-detected bottom lines may contain heave information. To remove heave from sounder-detected lines use the Arithmetic line operator to subtract heave (as a line) from the sounder-detected bottom line. This is useful when you use a Heave source to account for platform movement.
A line depth data GPGGA variable represents altitude data from the GPS antenna. Positive depths are downward. To convert depth values to altitude, where positive altitude is upward, create a virtual line with the Linear offset operator and set Multiply depth by to -1. Next create an editable line based on the Linear offset operator to use with a Platform or a virtual variable chain. This technique may also be useful for Heave source lines.
It is advised that you use a separate folder for each survey. Echoview can read data from a folder with files from multiple surveys. However, the provisions in order to read survey data correctly are that file names, dates and times must be in a standard format. Otherwise, data may be read incorrectly or incompletely.
Ex60 Power, Power to Sv and TS
Marker regions are created for Annotation datagrams associated with Vertical markers.

Ex60 .raw files use a naming convention like the following:

L004-D19970208-T043746-EK60.raw

where the components are:

- a survey line identifier. This is a string identifying a survey line. It often takes the form "Lnnnn" but other forms are accepted.
- the date (Dyyyymmdd)
- the time (Thhmmss)
- an optional equipment identifier. This is a string of 4 characters, typically "EK60".

.out and .bot files contain sounder-detected bottom information. Early versions of the logging software write .out files while later versions write .bot files. You do not add .out and .bot to a fileset manually. Instead, Echoview will search for the files in the same folder as the .raw file and if Echoview finds any which share the same survey line identifier and correct date and time, it will use these. For each RAW telegram in the .raw file, Echoview will attempt to find a matching DEP or BOT telegram in the .out or .bot file (that is, sharing the same time stamp). If it finds one, the depth recorded in the DEP or BOT telegram is reinterpreted as range and stored as the sounder-detected bottom range for that ping (that is, a point on the sounder detected bottom line). Echoview EV and EVI files register the sounder-detected line information. In a subsequent Echoview session, Echoview can detect if .out and .bot files are missing and will update the EVI file. When .out and .bot files do not exist or are missing you can pick a bottom line.

.out files are not added to Echoview filesets. Echoview reads them automatically when available. See the text and note above for details.

.idx files are not used by Echoview.

Live-viewing of .raw, .out and .bot files is supported using Echolog 60.

If you are using an Ex60 echosounder you are encouraged to contact Echoview support about your raw data processing requirements.

Note: Echoview reads and uses Ex60 data up to the penultimate point where the first corrupt data is encountered. The data file is marked with an icon in the Filesets window and a message is sent to the Message dialog box. Other forms of data corruption (incorrect telegram size, zeros to the end of the file) are similarly flagged as Echoview scans the file looking for valid data it can read and display.

Multiplexed variables

The National Marine and Fisheries Service has used (seemingly) otherwise unused fields in the .raw file format to store a channel number in an effort to support more transducers in the one file format than is otherwise possible.

To direct Echoview to interpret such data:

Before any data files are added to a fileset select Interpret Ex60 multiplexed channels on the EV File page of the EV File Properties dialog box.
Add the files, containing the multiplexed data, to the fileset.

If Echoview detects an expected value channel encoding (as specified by the Nation Marine and Fisheries Service) in such a field when you add a data file, you will be asked if you want to interpret such files as multiplexed data. If yes, then "(channel c)" - where c is the channel number - will be appended to the standard variable name, e.g. "Sv raw pings T1 (channel 1)" and that particular EV file will thereafter automatically read such data files in the same way. If no, then Echoview will ignore this particular channel encoding for all Ex60 .raw files added to this EV file thereafter. You cannot change this setting in an EV file once it is selected.

To see the status of the multiplex interpretation option in an EV file:

Display the Filesets window
If you see variables with "(channel c)" at the end of their name, then this EV file has the multiplex interpretation option set.
If you do not see any variables with "(channel c)" at the end of their name, then this EV file does not have the multiplex interpretation option set.
You can also see the status of this option under File on the Details dialog box for any Sv, TS or Angular position variable.
If NMFS multiplexing information is disabled, you will see a message in the File category of the Details dialog box.

This setting is applied when the EV file is used as an EV file template.

Contact Echoview support for further information on multiplexing channels in .raw files.

Note: Echoview supports 32 transducers and 128 channels for Simrad Ex60 multiplexed data.

EK500 telegrams logged with Simrad ER60 software (.DG)

Internally this format consists of the binary telegrams output by a Simrad Ex60 echosounder on its Ethernet port and written to disk with Simrad's ER60 logging software. Each telegram is preceded by a four-byte number stored in little-endian format. This number contains the length in bytes of the following telegram.

These files are named in the format: "Dyyyymmdd-Thhmmss.DG", where "yyyy" is the year, "mm" is the month, "dd" is the day, "hh" is the hour, "mm" is the minute, "ss" is the second at which logging commenced.

If you are logging B telegrams using ER60 software you should be aware that angular positions are stored with a lower precision in B telegrams (64 steps) than in Ex60 .raw files (128 steps). Furthermore, the ER60 version 2.0.0 encodes B telegrams incorrectly (this is a known bug that Simrad plan to correct with a new release of the ER60 software, please contact Simrad for further information). Echoview Software strongly recommends you do not log B telegrams from an Ex60 echosounder, and use the .raw format instead.

Ex60 data files logged with Echolog 60 (.ek60, .ek6)

.ek60 and .ek6 files are compressed data files that combine Ex60 .raw and the related .out or .bot files (if any) into a single file.

They are written by Echolog 60 during live viewing if the Enabled option is selected on the Echolog 60 settings dialog box. The files name format is: "X.ek60" (or "X.ek6"), where "X.raw" is the name of the .raw file that is being compressed.

Versions of Echolog 60 up to 3.25 produce .ek6 files.
Versions of Echolog 60 from 3.30 produce .ek60 files.

SM2000 FR data files (.raw, .bfm, .bmf, .nnn)

These files contain multibeam data logged from an SM2000 FR echosounder. Raw, unbeamformed data (.raw/001/002) and beamformed data files (.bfm/001/002 or bmf/001/002) are represented in Echoview as multibeam echogram replays.

When logging raw data, the SM2000 FR lays down X.raw files (where X is the filename and .raw is the extension). When the maximum file size is reached it continues logging to the file X.001 and then X.002 and so on opening a new file whenever the current file has reached the maximum file size limit.

When logging beamformed data, the SM2000 FR lays down X.bfm or X.bmf files, continuing the sequence with X.001, X.002 and so on as with raw bdata logging. The filename X is unique to each logging run and typically different from that used if logging raw data simultaneously. Thus, the .001, .002 ... sequence of files can be associated through the filename with their original .raw or .bfm/bmf file.

Echoview typically sorts data files alphanumerically when adding them to a fileset. Because the SM2000 FR filename sequence does not result in chronological order when sorted alphanumerically, Echoview will associate .raw and .bfm/bmf files with their subsequent sequence files when adding files to a fileset.

Note: The Add Data Files dialog box will display a list of files sorted by default alphanumerically. As a consequence, on large lists of files, the raw and .bfm/bmf files may appear below the associated .001/.002/... files. It is possible to sort this list by date (click the View menu button then choose Detail and click the Date Modified column header in the resulting list) which should sort these files in the order of their collection.

These data files contain received power signal measurements represented by an amplitude and quadrature component which are made available as multibeam magnitude and multibeam phase variables respectively in Echoview. The underlying data export format is in-phase sample, quadrature sample, in-phase sample, quadrature sample, etc.

If roll data is recorded in the data file Echoview will provide a roll variable.

Live-viewing of these files was supported using Echolog SM from Echoview 4.

Note: Raw data files that contain multiple pings with the same recorded time are processed so that each (co-incident) consecutive ping has 1ms added to its time in a compound fashion.

SM2000 FR data files logged with Echolog SM (.sm2000)

.sm2000 files are compressed SM2000 data files (.raw, .bfm, .bmf, .nnn) files. They are written by Echolog SM during live viewing if the Enabled option is selected on the Echolog SM Settings dialog box. The file name format is: X.ext.sm2000, where "X" is the name of the SM2000 data file being logged, ".ext" is the original file extension of the SM2000 FR data file, and ".sm2000" is the file extension, e.g. 02J03003.raw.sm2000. Note, Echolog SM is not supported or available.

ME70 raw data files (.raw)

Support for the ME70 is in a continuing state of development. Our long term intention for ME70 support is to base the next generation of sonar data visualization and analysis tools on the uniquely flexible capabilities of the ME70. Visualization and analysis engines that can handle completely flexible sample positions will have huge benefits across all branches of fisheries acoustics. We are continuing to refine our future development program for the ME70 as more details and data become available.

In planning these developments we are committed to basing our plans upon the needs and wants of the future ME70 user base. Through consultation with the manufacturer and potential users, we look forward to continuing to build support for the ME70 and further refining our future plans.

The Simrad ME70 multibeam echosounder produces beams that can be individually configured to point in any direction within a planar fan.

The ME70 .raw file format is functionally similar to the Ex60 .raw format with each beam identified by an independent transducer channel. Echoview represents each ME70 beam as a single beam variable in the same manner as the channels on the Ex60 series of echosounders. ME70 single beam variables have a Minor Axis steered angle and a Major Axis steered angle based on ME70 Alongship and Athwartship beam steering angles from the data file. The single beam variable's sample depths are calculated with respect to the beam steering angles.

A multibeam variable is derived that represents all beams from each transducer channel in a planar fan, or swath view. Each beam of the fan is derived from the equivalent Sv single beam variable. Currently, overlapping beams are not supported. Data containing overlapping beams will not result in a derived multibeam variable.

Support for beam directions includes the athwartship coordinate (or DirY field) which is defined in Echoview as the beam angle. Beam numbering starts from the leftmost beam in the sector plot and the beam angle is referenced to the central axis of the transducer. Support for beam direction in the alongship direction (DirX field) is planned for future development.

Where angular position data is available, an angular position pings beam formed variable is derived in a way similar to the process for the Sv single beams to Sv multibeam variable. The beam geometry of the angular position pings beam formed variable matches that of the multibeam Sv variable.

Sv and TS values are calculated from raw power data using the Ex60 algorithms.

Echoview supports heading data output ($INHDT) by the Applanix POS MV instrument, as well as NMEA $GPHDT strings containing heading data.

Note: You can select Create and/or associate transducers based on frequency when new raw variables are derived on the Fileset Properties dialog box to create transducers based on transducer frequency. However, this process doesn't support the configuration of the steering angles for the transducers.

ME70 software version 1.4.0 *.raw files

Echoview reads ME70 software version 1.4.0 recorded data that includes binary and XML information. Echoview expects the structure of the binary data to be the same as pre-version 1.4.0 binary data. Echoview rounding of frequency values may slightly affect the match to XML values.

SH80 data files (.dat, .dzt)

The Simrad SH80 scanning sonar records data in files with the extension .dat or .dzt (compressed files). These files can contain GPS data, heading data and acoustic data in V-mode (the Simrad term for this is "Vertical slice") or H-mode (the Simrad term for this is "Omni"). There are 64 beams in either ping mode. The acoustic data from these files are represented in Echoview as multibeam echograms.

Instrument specific features are as follows:

H-mode sample data and V-mode sample data are grouped within the telegrams. A group is defined as all samples occurring at a specified range over all beams. If Echoview finds that group data is missing the missing samples are given a No data value.
H-mode pings can have a bearing that is not aligned to the ship's axis.
Echoview calculates Sv using the Multibeam magnitude to Sv algorithm, where the TVG is 20 and the user specified absorption coefficient is as specified on the Calibration page of the Variable Properties dialog box.
If the data file does not have an Ownship data telegram, the associated ping data is not added to the acoustic variable.

Note: If you are using V-mode or H-mode variables, Echoview requires that the transducer they are associated with has an elevation, azimuth and rotation of zero. If you try to display an echogram and this requirement is not met, a warning message will be displayed.

Range calculations

The Simrad SH80 range algorithm is:

Start range = 0 m

Stop range = Sound Speed × Sample rate × Number of samples in a beam × 0.5

Where:

Sound speed (m/s) as read from the SoundSpeed field of the Start ping telegram

Sample rate (s/sample) is 1/Bandwidth/Sample decimation

Bandwidth (Hz) as read from the Bandwidth field of the Start ping telegram

Sample decimation as read from the SampleDecimation field of the Start ping telegram

Number of samples in a beam as read from the SamplesRequested field of the Start ping telegram

SP70 data files (.dat, .dzt)

The Simrad SP70 scanning sonar records data in files with the extension .dat or .dzt (compressed files). These files can contain GPS data, heading data and acoustic data in H-mode (the Simrad term for this is "Omni"). There are 64 beams in this ping mode. The acoustic data from these files are represented in Echoview as multibeam echograms.

Instrument specific features are as follows:

The Heading field of the Start ping telegram contains the heading of the transducer added to the ship's heading. When the data is read and displayed by Echoview, the ship's heading is removed.
If the data file does not have an Ownship data telegram, the associated ping data is not added to the acoustic variable.

Range calculations

The Simrad SP70 range algorithm is:

Start range = 0 m

Stop range = (Sound speed/Frequency) × Number of samples in a beam × 0.5

Where:

Sound speed (m/s) as entered on the Calibration page of the Variable Properties dialog box

Frequency (kHz) as read from the Start ping telegram.

Number of samples in a beam as logged in the RangeStop field of the Start ping telegram

Sv calculations

Simrad SP70 underlying data has a Simrad TVG correction applied to it. To calculate Sv, Echoview removes Simrad's TVG correction and applies a value of 20dB instead.

Sv = Underlying value - (20 - Simrad TVG correction) × log10 (r)

Where:

Underlying value (dB) as stored in the data file

Simrad TVG correction (dB) is the Simrad correction logged for the Underlying value, as read from the TVG field of the Start ping telegram.

r (m) is the range of the sample

SU90 data files (.raw)

The Simrad SU90 is a long range, low frequency fish finding sonar. Echoview reads Simrad SU90 data, NMEA, vessel log, heading and GPS data from *.raw files. Echoview calculates power and Sv from raw data. Range calculations, TVG and ping mode calculations are identical to the calculations outlined for the Simrad SH90 data .raw format. For more information refer to the Simrad website.

SC90 data files (.raw)

The Simrad SC90 is an omnidirectional, high frequency fish finding sonar. The cylindrical multi-element transducer allows the omnidirectional sonar beam to be tilted electronically from +10 to -60° in 1° steps. Echoview reads Simrad SC90 data, NMEA, vessel log, heading and GPS data from *.raw files. Range calculations, TVG and ping mode calculations are identical to the calculations outlined for the Simrad SH90 data .raw format. For more information refer to the Simrad website.

Note: SC90 V-mode and H-mode variables such as TwoWayBeamAngle and TransducerGain may not be accurate across the range of pings as Echoview uses the value from the first beam only.

SH90 data files (.raw)

The Simrad SH90 is a high resolution, high frequency fishery sonar that outputs beamformed data in .raw files. This sonar can electronically correct the beam for pitch and roll (± 20 degrees) with an activated beam stabilizer system. For more information refer to the Simrad website.

Echoview supports NMEA vessel log/heading/GPS in Simrad SH90 data files.

Range calculations

StartRange = 0.5 × SampleHeight

StopRange = StartRange + DataRange

Where:

StartRange
= the start of the first sample in the ping

StopRange
= the end of the last sample in the ping

SampleHeight
=
SoundVelocity × 0.5 × SampleInterval

Where:

SoundVelocity is read the RAW1 datagram in the data file.

SampleInterval is read from the RAW1 datagram in the data file.

DataRange =
SampleHeight × DataPoints

Where:

DataPoints is Counts and is read from the RAW1 datagram in the data file.

Sv calculations

Echoview uses the Simrad Ex60 Sv formula to calculate SH90 Sv values. And similarly for SU90 and SX90 Sv data.

TVG calculations

Echoview applies Ex60 Time Varied Gain and Ex60 TVG range correction to Simrad SH90 Sv data for ranges greater than one meter.

Ping modes

Echoview calculates a bearing from data in the file but may not display information about the reference line for the bearing.

H-mode variables

Data may be recorded for omni-beam operation where all beams have the same beam-tilt angle. Such data is the source for Echoview H-mode raw variables.

Echoview (Beam 0) Bearing = HeadingFile + AlignmentFile (degrees)

Tilt = TiltFile (degrees)

Where:

HeadingFile is Heading read from the RAW1 datagram in the data file.

AlignmentFile is DirZ read from the CON0 datagram in the data file. The value for Alignment is displayed in the Details dialog box. Use Alignment to specify the Beam rotation (degrees) on the Geometry page of the Transducer Properties dialog box.

TiltFile is DirX read from the RAW1 datagram in the data file.

V-mode variables

Simrad vertical-slice beam operation records data for a beam fan at a specific bearing and tilt. Such data is the source for Echoview V-mode raw variables.

Echoview (Beam 0) Bearing = AlignmentFile + BearingFile + 90 (degrees)

Where:

BearingFile is DirY read from the RAW1 datagram of the data file.

Values displayed in Echocheck

Echocheck name	Description
Gain (Tx + Rx)	Echoview uses GainTx + GainRx for the TransducerGain.
DirZ	DirZ from the CON0 datagram is read to represent the transducer bearing. This is displayed as the Alignment under the File section of the Details dialog box.
BeamWidthHorizontalRx	BeamWidthHorizontalRx is read as MinorAxis3dBBeamAngle.
BeamWidthVerticalRx	BeamWidthVerticalRx is read as the MajorAxis3dBBeamAngle.

SX90 data files (.raw)

The Simrad SX90 is a long range, low frequency omnidirectional fish finding sonar that outputs beamformed data in .raw files. This sonar can electronically correct the beam for pitch and roll (± 20 degrees) with an activated beam stabilizer system. The SX90 may also vary the gain to minimize impact of noise on the receiving system. For more information refer to the Simrad website.

Echoview supports NMEA vessel log/heading/GPS in Simrad SH90 data files.

Range calculations, TVG and Ping mode calculations are identical to the calculations outlined for the Simrad SH90 data .raw format.

Notes:

A line depth data GPGGA variable represents altitude data from the GPS antenna. Positive depths are downward. To convert depth values to altitude, where positive altitude is upward, create a virtual line with the Linear offset operator and set Multiply depth by to -1. Next create an editable line based on the Linear offset operator to use with a Platform or a virtual variable chain. This technique may also be useful for Heave source lines.
Echoview compares recorded beam mode to recorded tilt and bearing angles. When beam mode is inconsistent with the tilt and bearing angles, Echoview assigns ping mode by inferring it from the tilt and bearing angles. If this happens, a message is sent to the Messages dialog box.

EK15 data files (.raw)

The Simrad EK15 is a single (high) frequency scientific echosounder. Its functionality includes usage with multiple transceivers and raw data logging. For more information refer to the Simrad website.

The Simrad EK15 .raw file format is functionally similar to the Ex60 .raw format for single beam echosounders. Derived raw acoustic variables, position variables and raw line variables are based on Simrad Ex60 .raw file support. Simrad EK15 data may be live viewed as for Ex60 data in Echoview.

Ex70 data files (.raw)

The Simrad Ex70 is a high accuracy single/split beam echosounder capable of logging data for six frequencies simultaneously. For more information refer to the Simrad website.

The Simrad Ex70 .raw file format is functionally similar to the Ex60 .raw format for single and split beam echosounders. Derived raw acoustic variables, position variables and raw line variables are based on Simrad Ex60 .raw file support. Simrad Ex70 data may be live viewed as for Ex60 data in Echoview.

EK80 data files (.raw, .bot, .xyz)

The Simrad EK80 Scientific wideband echosounder outputs *.raw data files. Where the EK80 is configured as a wideband instrument, Echoview reads (transceiver pulse) slope, TVG, pulse duration, transceiver impedance and when available tabulated frequency dependent calibration values from the data file. Frequency dependent transducer gain, beam width, frequency and Simrad LOBE beam compensation interpolated as required for EK80 raw variables, the Single target detection - wideband operator and the Wideband Frequency Response graph. Within the bandwidth of the transmitted pulse, values are interpolated. For frequencies outside the bandwidth, the closest value is used. Echoview derives complex power, complex Sv, complex TS and complex angular position variables and corresponding pulse compressed variables using signal processing and proprietary Simrad algorithms. Angular position data is derived from angle calculations based on the raw data. In the absence of frequency dependent data, Sv, TS and angular position are calculated with respect to a nominal frequency.

Echoview reads temperature, acidity and salinity from the data file and uses the Francois & Garrison (1982) equation to calculate absorption coefficients. Data for each wideband is displayed as a separate raw variable.

Where the EK80 is configured as a single frequency instrument, Echoview derives raw variables that may include Power. multiplexed data, MajorAxis3dbBeamAngle, MinorAxis3dbBeamAngle, Sa correction and active transducer transmission characteristics. Single frequency EK80 variables are able to use the value for AbsorptionCoefficient when it is specified in an ECS file.

Data from wideband or single frequency instrument configurations can be recorded in the same data file. See also About transmitted pulse.

Echoview reads heading, pitch and roll recorded by a Simrad Motion Reference Unit.

Echoview reads EK80 annotations and creates marker regions.

.raw files also contain NMEA sentences, of which Echoview supports the following subset:

$ECGxx, $GPGxx, $AGRMC, $AGGLL and $INGxx sentences containing GPS fixes
$SDVLW containing vessel log data
$GPHDT, $GPVTG, $INHDT and $INVTG containing heading data
$PSIMP containing depth sensor data
$IIDBS containing depth sensor data
$GPGGA containing altitude data

Echoview derives an individual position GPS variable for each GPS NMEA sentence. A (combined) position GPS variable is also derived, and it contains data from all the GPS NMEA sentences.

Echoview can also read the KM Binary packet within the MRU1 datagram recorded by the *.raw file which contains GPS, heading, pitch and roll data from an Applanix POS MV instrument. Echoview uses the MRU1 timestamps for KM Binary data.

EK80 CW data saved as Power/Angle data or Power/Angle data with a reduced sampling rate. This data may be affected by a known issue.

Active and passive ping data (see TransducerModeActive) recorded in Simrad EK80 data files.

Transducer and platform metadata

Echoview reads Transducer depth, Transducer name and Device name from the file attributes TransducerDepth, TransducerName and Version. For files recorded by Simrad EK80 software version 1.2 or later, Echoview reads and uses the platform and transducer metadata:

File Water Level Offset is assigned as the value for Platform position, Z co-ordinate of the water level (m). This attribute is unavailable in files recorded by software versions earlier than 1.2.
File Alongship Transducer Offset is assigned as the value for the Transducer location X - alongship offset (m). Software versions earlier than 1.2 may record this metadata and in that case consider reviewing the interaction of Transducer location Z - vertical offset with the Platform Z co-ordinate of the water value. Adjust values if it is required.
File Athwartship Transducer Offset is assigned as the value for the Transducer location Y - athwartship offset (m).
File Vertical Transducer Offset is assigned as the value for Transducer location Z - vertical offset (m).

Supported EK80 systems

When loading EK80 data, Echoview reads the system name from *.raw data file.

If the system belongs to the *.raw files output by Simrad EK80 WBT, WBAT, EKAuto systems and *.raw files output by Kongsberg EA640 echosounders (refer to the Simrad website for information about the EK80), Echoview loads that data according to that system's specifications.

If the data file does not specify a system name, Echoview reads it according to the EK80 *.raw format, and issues a warning in the Message dialog box.

Otherwise, if Echoview does not recognize the specified system name, it displays an error message and does not load the data.

*.xyz Notes

Echoview supports .xyz files containing sounder-detected bottom information. .xyz files are located in the same directory as .raw files. There is a separate .xyz file for each channel. A sounder-detected bottom line is generated for each channel in an EK80 .raw file that has a corresponding .xyz file identified with the name "<raw-filename>-<channel-id>.xyz", where channel-id is either the ChannelIdShort or ChannelId field from the channel metadata. Illegal filename characters are replaced with a space character. An .xyz file is valid when the expected number of fields is found in the first line. An error is displayed if validation fails, and the .xyz file data is not read. A depth value for each ping is created, provided there is a corresponding entry in the .xyz file within 10ms of that ping. The generated EVI file will not be invalidated if the .xyz files are added, removed or changed.

Existing EV files that use EK80 data files, and which are also accompanied by an .xyz file (in the same folder), are automatically updated with new sounder-detected line variables upon opening in Echoview. Be aware that live-viewing does not support .xyz files.

Echoview assumes that *.xyz recorded zero depth represents an invalid depth and that consecutive values of -2 depth indicates the end of recorded depths in the file.
Echoview supports the earlier version of the *.xyz file and the version which changed the record format of latitude and longitude values.

Echoview supports .bot files containing sounder-detected bottom information. .bot files are located in the same directory as .raw files. When both .bot and .xyz files are found, Echoview only reads and uses data from .bot files. Support includes the handling of EK80 file values for Transducer Mounting, Transducer Offset Z, Drop Keel Offset and Water Level Draft in order to adjust bottom line data for display on echograms. Echoview calculates adjustments to sounder-detected lines based on the Transducer Mounting type read from the data file. Each supported mounting type has a specific vertical depth offset. A message is displayed when an unsupported mounting type is read. If you have a sound-detected line recorded under the unsupported Transducer Mounting type - Towed, it is likely that a line operator will be required to vertically adjust the line so that it displays at the correct depth.

Support for the EK80 is in a continuing state of development. Our long-term intention for EK80 support is to develop sonar data visualization and analysis tools on the unique capabilities of the EK80 instrument. Visualization and analysis engines that can handle pulse compression data will have huge benefits across all branches of fisheries acoustics. We are continuing to refine our development program for the EK80 as more details and data become available.

In planning these developments, we are committed to basing our plans upon the needs and wants of the future EK80 user base. Through consultation with the manufacturer and potential users, we look forward to continuing to build support for the EK80 and further refining our plans.

Simrad EK80 EC150-3C (.raw)

Echoview reads echosounder data from Simrad EK80 EC150-3C *.raw files. The derivation of Sv and TS variables is based on EK80 equations however EC150-3C data has some differences.

Notes on the EK80 data format support in Echoview

It is best to use *.raw files created with the most up to date (and well-defined) Simrad EK80 file format specification. Some EK80 files supported in Echoview 6.1 may not be supported in the latest version of Echoview.
Echoview can encounter the case where no expected *.bot file is found. Echoview then searches for .bot files that have the same prefix as the .raw file, and will use the .bot file that is closest to the .raw file's timestamp. The time constraint between the .raw and the .bot file is three days.
The single target detection - wideband operator accepts pulse compressed complex TS and pulse compressed complex angular position operands. TS, Sv and TS and single target data may be analyzed in a Wideband Frequency Response graph.
See also EK80 Power, Power to Sv and TS.
Echosim 80 and Echolog 80 enable the live viewing of Simrad EK80 *.raw data.
Simrad ES80 *.raw data is handled in the same way as Simrad EK80 data.
Calibrations settings are read from EK80 data files. The settings may be modified using an Echoview ECS file. Care should be taken to correctly specify calibration settings, otherwise incorrect or unexpected calculations may occur. See also Array position and element number note.
When fileset (of files) includes a file with data from a Wide Band Transceiver (WBT) and a General Purpose Transceiver (GPT), two T1 variables with the same name can occur. Use the Details dialog box Channel ID to determine the data source for the variable.
Pulse form information is displayed on the Details dialog box. Note: An acoustic variable title's frequency band is displayed as Low frequency-High frequency, even in the case of a linear decreasing chirp.
In Echoview, there may be discrepancies in a few random samples when EK80 CW data recorded as complex data is compared to the same EK80 CW data recorded as non-complex data.
RxSampleFrequency is stored as part of the XML0 Configuration datagram for all recordings using EK80 1.12.2. However, RxSampleFrequency is not written to file when raw files are recorded with older versions of Simrad EK80 software. When RxSampleFrequency is missing from a data file, Echoview applies a TransceiverSamplingFrequency associated with the TransceiverName, in EK80 calculations. Down-sampled EK80 CW data may be affected by this issue.

Where RxSampleFrequency is missing and TransceiverName includes Echoview applies this TransceiverSamplingFrequency value

GPT 500000

SBT 50000

WBT HP 187500

WBT LF 93750

WBAT 1500000

WBT TUBE 1500000

WBT MINI 1500000

WBT 1500000

If the TransceiverName is not in this list, Echoview estimates the sampling frequency by multiplying the ping sampling frequency with the decimation factors. It may be useful to check that the CW calibration value for EffectivePulseDuration is reasonable (e.g. it should not be larger than PulseDuration); this can be reviewed through the Calibration page of the Variable Properties dialog box.
From Echoview 11 onward, Echoview is unable to read an ECS file that contains data under the calibration setting 'ImpedanceTableWideband'. Echoview reads such data, when it is present in an EK80 data file. However, Echoview does not use the data for EK80 calculations. If this affects your EV file, edit the ECS file and change 'ImpedanceTableWideband' to 'TransducerImpedanceTableWideband'.
See also Correction to transducer gain calculations in Simrad EK80 wideband data.

For further information about wideband and wideband pulse compressed data refer to About transmitted pulse.

Omnisonar netCDF (.nc)

Echoview reads ICES SONAR-netCDF4 file format *.nc files recorded by optionally licensed Simrad omnisonar SU90, SN90, MF90, CS90, ST90, SX90 and SY50 omni sonar, and SN90 fishery sonar systems. netCDF Type 1 equations are used to handle water column data.

Multibeam calibration settings

Echoview does not support per-beam calibration for multibeam data. However, if the *.nc data file records

transmit_frequency_start
transmit_frequency_stop
absorption_indicative
transducer_gain
equivalent_beam_angle (Sv only)

that vary from beam to beam, Echoview will use the per-beam values to determine the correct Sv and TS values. Note that these per-beam values are not listed under the settings on the Calibration page of the Variable Properties dialog box.

When operating in V-mode Echoview does not support

Arbituary tilt angles per beam. However, it will use the beam angle recorded in the data file to calculate the correct Sv and TS values. Note that the per-beam tilt angles are not listed on the Calibration page of the Variable Properties dialog box.
Different per-beam bearing angles. The pings are represented as straight fans with a bearing of 0 degrees.

Simrad MS70 data files (.raw)

Simrad MS70 provides a 3D acoustic matrix of 500 stabilized beams (25 horizontal and 20 vertical) in a single ping. Echoview reads Simrad MS70 high resolution, multibeam scientific sonar records .raw files and derives matrix raw variables for the water column data. Matrix acoustic variables represent data recorded by sonars that ping with the 3D matrix of beams. Data for a specified sector and angle of the matrix may be extracted by Echoview operators and handled as multibeam data. Echoview does not derive single beam variables for each of the 500 individual beams. For more information, see About matrix data.

Like the Simrad ME70, each beam in an MS70 matrix is a separate transducer with its own calibration. When viewing the Calibration page on the matrix variables (which encompass all beams) of the Variable Properties dialog box, most of the calibration settings are taken from the first beam in the matrix. Some of the calibration settings are taken from the union of the beams, including:

The start/stop range are from the minimum/maximum range across all beams.
Data points are the maximum of data points across all beams.

To view the individual beam calibration settings, extract a sector of the matrix using the Sector select operator, then hover over the beams in the multibeam echogram. This will reveal the values in the Beam calibration section of the Details dialog box.

StartRange	=	the start of the first sample in the ping
StopRange	=	the end of the last sample in the ping
SampleHeight	=	SoundVelocity × 0.5 × SampleInterval Where: SoundVelocity is read the RAW1 datagram in the data file. SampleInterval is read from the RAW1 datagram in the data file.
DataRange	=	SampleHeight × DataPoints Where: DataPoints is Counts and is read from the RAW1 datagram in the data file.

Where RxSampleFrequency is missing and TransceiverName includes	Echoview applies this TransceiverSamplingFrequency value
GPT	500000
SBT	50000
WBT HP	187500
WBT LF	93750
WBAT	1500000
WBT TUBE	1500000
WBT MINI	1500000
WBT	1500000