Furuno data files

Echoview supports data files from these Furuno echosounders:

FQ80
ETR-30N
FCV-30
FCV-38
FSV-25
FSV-30 (Research version)

Some Furuno data files may be verified by Echocheck.

FQ80 Data files

Supported file types

Echoview does not directly support .hacorg files logged by FQ80 echosounders. It supports .hac files that are created from these files by Furuno's FQ80 Analyser software (see Furuno FQ80 Analyser documentation for more information).

The following FQ80 files types are supported.

File type	Description
PingAn01.hac	Mechanical angle pings
SCSVn06.hac	Sv small-cell pings
SSVn03.hac	Sv pings
TSn04.hac	Single target detection pings

Where n = channel number

Pos.hac files (GPS positions) are also supported but cannot be added to a fileset directly. Echoview will look for a pos.hac file in the Position folder when any of the files types listed above are added to a fileset. If a pos.hac file is found, Echoview will derive a position GPS fixes variable which can be viewed as a cruise track.

Support for other FQ80 file types is being considered for inclusion in future versions of Echoview. Please contact Echoview support to discuss your requirements.

Folder structure

Echoview requires that data files are stored in the folders to which they were written by the FQ80 during logging, i.e. for any root folder, the following folders must exist:

\Channel
\Echo
\Ping or \PingAngle
\Position (this folder is optional)

Note: Echoview and associated programs do not support the use of some international character sets. If any folders in the filepath contain characters other than Latin alphabet characters, you should rename the folders. See International character support for more information.

File names

Echoview will look for files using their default file names (see above). Do not change file names or Echoview may not read the file at all or may read it as an incorrect file type.

Adding data files to a fileset

The Furuno FQ80 stores and names data files quite differently to any other supported echosounder. As a result, you cannot add data files to a fileset in the same way that you would for files from other echosounders. Two rules apply to adding FQ80 files to a fileset:

You can only add a single data file to each fileset.
You can only add SCSVn06.hac, SSVn03.hac, and TSn04.hac files to a fileset from the Ping folder.
You can only add PingAn01.hac files to a fileset from the PingAngle folder.

Note: Although you can only add data files from the folders listed above, Echoview requires that certain files be present in other folders. For example, you cannot add a file from the Ping folder to a fileset unless a file of the same name (excluding channel number) exists in the Channel folder and Echo folder. The required files will have been written during logging and must not have been renamed or moved out of the folder to which they were written.

See Adding and removing data files for general information about adding data files to a fileset.

Time resolution of pings

The transmit time for pings is stored at a resolution of one second. If the transducer's ping rate was greater than one ping per second during logging, multiple pings are assigned the same transmit time. Echoview requires that all pings have a unique transmit time and will shift transmit times as required. Echoview will shift each duplicate transmit time by 0.1 of the ping interval value read from the fff.hac file in the Echo folder (where fff is the same filename as the data file from the Ping folder that was added to the fileset).

Values used in calculations

The following information is presented as a reference. You do not need to be familiar with this information in order to make use of your data.

Sound speed

The sound speed value used in any calculations will be the value read from the fff.hac file in the Echo folder (where fff is the same filename as the data file from the Ping folder that was added to the fileset).

Sample thickness

For a file fff.hac in the Ping folder that was added to a fileset, the sample thickness value used for ping geometry and other calculations will be calculated by Echoview as follows:

sample thickness = c / f / 2

Where:

c = sound speed (read from the fff.hac file in the Echo folder)
f = channel sampling frequency (read from the fff.hac file in the Channel folder)

The sample range value from fff.hac file in the Echo folder (where fff is the same filename as the data file from the Ping folder that was added to the fileset) is not used.

Pulse duration

The pulse duration used in calculations will be calculated by Echoview. See FQ80 Pulse duration for more information.

ETR-30N data files

Supported file types

Echoview supports ETR-30N data files with the following naming system:

TTYYYYMMDDhhmm.bin

Where:

TT identifies the type of data stored in the file and is one of:

HF
for high frequency Sv ping data

LF
for low frequency Sv ping data

LL
for position data

PhHF for high frequency phase data

PhLF for low frequency phase data

YYYYMMDDhhmm identifies the date and time of data logging as follows:

YYYY:
year

MM:
month

DD:
day

hh:
hour

mm:
minute

Calibration of Sv variables

Sv values from ETR-30N Ping data files are calibrated (in the file). Echoview provides the option of applying a calibration offset is desired.

See About calibrated data for more information.

Values used in calculations

The following information is presented as a reference. You do not need to be familiar with this information in order to make use of your data.

Sample thickness

The sample thickness value used for ping geometry and other calculations will be calculated by Echoview as follows:

sample thickness = c / f / 2

Where:

c = SoundSpeed, as displayed on the Calibration page of the Variable properties dialog box
f = SamplingFrequency, as displayed on the Calibration page of the Variable properties dialog box

Furuno FCV-30 data files

Echoview supports Furuno FCV-30 data written by the instrument in a .hac format. Echoview reads the tuples that include the Ping U-32 tuple, Ping-32-16 angles tuple and standard HAC version 1.0 Standard navigation tuple (30). Single target data can be achieved using the Echoview operator called Single target detection - Furuno FCV-30. This operator finds Furuno single targets in processed compensated TS data output by the Furuno FCV-30 sounder.

In addition, a proprietary Furuno beam compensation model is available for use with Echoview's Single target detection - split beam (Method 1 and Method 2) operators. For more information about the Furuno beam compensation model please contact Furuno.

Furuno FCV-38 *.nc data files

Echoview reads *.nc Version 1 and Version 2 data files recorded by the Furuno FCV-38 split beam echosounder to the ICES SONAR-netCDF4 file format. Equations for power, TS, SV and angular position are derived from Furuno FCV-38 equations. File reading and echogram display times may be lengthy for large data files.

Furuno FSV-25 *.nc data files

Echoview reads ICES SONAR-netCDF4 file format *.nc data files recorded by the Furuno FSV-25 scanning sonar. Echoview can read 3dB beam angle values if they are recorded in the data file, however if the angles contain NAN values, the angles are not used by Echoview. Equations for power, TS, SV and angular position are based on Type 2 conversion equations intended for data recorded by Furuno omnisonars. File reading and echogram display times may be lengthy for large data files.

Echoview calculates the tilt and bearing for beam 0, and applies it to the remaining beams. The ICES netCDF sonar beam coordinate system uses the same conventions as the netCDF4 platform coordinate system but with the origin (0,0,0) at the transducer (Figure 1 of the ICES netCDF document). See also Transducer location, Fixed/Mobile Platform.

Tilt (degrees) = arcsin(beam_direction_z)

Bearing (degrees) = arctan(beam_direction_y/beam_direction_x)

Multibeam calibration settings

Echoview does not support per-beam calibration for multibeam data. Instead it applies the calibration settings from the first beam, to all beams. If the *.nc data file records

transmit_frequency_start
transmit_frequency_stop
absorption_indicative
receiver_sensitivity
gain_correction
equivalent_beam_angle (Sv only)

that vary from beam to beam, the Sv and TS values will be incorrect and a warning message will be displayed.

Per-beam calibration settings that may affect other echogram calculations include:

beamwidth_receive_major
beamwidth_receive_minor
beamwidth_transmit_major
beamwidth_transmit_minor

Notes:

Echoview doesn't support negative start range and as a result the first sample may not be used.
Echoview's handling of Furuno FSV-25 bearing offset data improves with an increase in the number of beams.

Furuno FSV-30 (Research version) *.fsv data files

This transducer model is sometimes abbreviated to Furuno FSV-30R.

Echoview reads *.fsv data files recorded by the Furuno FSV-30 (Research version) transducer system. These files may contain GPS data, heading data and acoustic data as V-mode, H-mode or S-mode.

The raw Sv variable data can be exported to the *.nc file format that can be added to a fileset.

Instrument specific features are as follows:

From the data file, Echoview can evaluate H-mode 3dB major-axis and minor-axis angles and read 3dB minor-axis transmit angles. Such H-mode data allows the calculation of the equivalent two-way beam angle which can then be used to calculate H-mode Sv values.
In V-mode, zero bearing indicates a beam fan oriented along the platform with beam 0 pointing forward. Bearing is measured clockwise when viewed from above. V-mode variables contain a 90 degree beam fan with 128 beams. Beam 0 is horizontal and beam 127 is vertical.
The tilt angle is measured uniformly for H-mode. It is always the angle from the horizontal, positive angles pointing downwards, negative angles upwards. H-mode variables have beam 0 pointing in the direction of vessel motion and numbered clockwise. The multibeam echogram views the H-mode cone from above. In head up mode beam 0 is pointing upwards on the screen.
The FSV-30 (Research version) can record data in a high gain and/or a low gain mode (at the same time if desired). High gain variables are recommended for display and school detection. Low gain variables are recommended for integration and biomass estimation. Regardless of which gain is applied, the Sv variable provided by Echoview has the gain removed and the standard 20Log(R) Sv gain applied. These two gains are available because the instrument performs real time beamforming on data in 16 bit linear space which can store a limited range of data. A high gain provides a window into lower values but may saturate with higher values (it is suited for finding boundaries between ambient background signal and significant echoes). A low gain provides a window into higher values without saturating (it is suited for estimating biomass, where the saturation would lead to an underestimate).

Notes:

Data products, files and variables derived from .fsv data in EV files saved using Echoview 4.9 or older may not be not compatible with the current file format support and may manifest as unavailable variables. Pre-existing EV files may need to be reviewed and updated. Layered TVG, Furuno *ecb files and per beam angle changes are not currently supported.
Echoview doesn't support negative start range and as a result the first sample may not be used.
Echoview skips pings where the bearing or tilt is out of range.
If you are using V or H variables, Echoview requires that the transducer they are associated with have 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.
The precision limitations of the netCDF4 format affect the match of start and stop ranges, bearing and tilt, and sample values for FSV-30 (Research version) Sv .fsv data exported to the *.nc format.
Furuno FSV-30 (Research version) magnitudes and Sv
International character support
Echoview does not read transducer offset from *.fsv files.