RESON data files

Echoview supports data files from the following echosounders:

SeaBat 6012
SeaBat 7000 series
SeaBat T20-P
SeaBat T50-R
SeaBat 8000 series

Some Reson files may be verified by Echocheck.

SeaBat 6012 files (.sbi)

The RESON SeaBat 6012 file format is supported in Echoview.

Data are stored in files with the extension .sbi. The files must be named in such a way, as an alphabetical sorting of the file names will sort them into date/time order.

Underlying data records an amplitude value for each sample.

SeaBat 7000 series (.s7k)

The SeaBat 7000 series echosounder uses a binary file format with the extension .s7k, to log data records. This file format may also be recorded by Norbit or Teledyn Odom sonars.

Echoview reads the following record types:

1008		7k Line Data Depth
1013		7k Heading Data
7000		7k Sonar Settings
7008+		7k Generic Data
7011		7k Image Data
7018+		7k Beamformed Data
7042		7k Compressed Water Column Data

+Echoview is able to read the 7018 record as well as the 7008 record. The 7018 record outputs superior (water column) magnitude and phase data as described in the RESON Data Format Definition Document - Addendum to SeaBat 7k data Format, Volume 1, Version 1.00, Revision E. For further information contact RESON http://www.teledynemarine.com/reson.

The 7k Generic Data record or the 7k Beamformed Data record contains magnitude and phase of the returned signal. The magnitude already has a time varied gain applied to it. The magnitudes are converted to Sv as follows:

Sv = 20log(M) - T * log(R) + 20log(R) + C

Where:

M is the magnitude read from the data file (proportional to voltage),
R is the range of the data point,
T is the spreading loss in dB, which is read from the 7k Sonar Settings record in the data file.
C is the CalibrationOffset (specified on the Calibration page of the Variable Properties dialog box, this is set by an ECS file).

Phase is calculated as follows:

Phase = 2π * A/216 (radians)

Where:

A is the phase value read from the data file

The 7k Image Data record contains processed magnitude data only. No Sv conversion is currently provided.

Echoview provides a position variable from GPS data if available. If roll data is recorded in the data file Echoview will provide a roll variable. If pitch data is recorded in the data file, Echoview will provide a pitch variable.

Echoview displays calibration settings for values read from file.

The 7k Compressed Water Column Data support includes reading sample data values, absoption coefficient, frequency and sound speed from file.

Notes:

Underlying data export is unavailable for these raw variables: magnitude complex beamformed pings, phase complex beamformed pings and Sv complex beamformed pings.
Where the angle for adjacent beams is the same, Echoview differentiates the beams by adding 0.0001 radians to the second beam.

SeaBat T20-P files (.s7k)

The SeaBat T20-P multibeam echosounder records data to the Reson 7000 *.s7k file format.

SeaBat T50-R files (*.s7k)

The SeaBat T50-R multibeam echosounder records 8-bit compressed data to the Reson 7000 *.s7k file format.

SeaBat 8000 series snapshot files (.sns/.raw)

These files contain data that was collected from a SeaBat 8000 series multibeam echosounder operating in the Snapshot/Acquire mode. Only snapshot files with the .sns or .raw file extension are supported; snapshot files with the .rdf file extension are not supported. Early versions of RESON SnapSaver generated .raw files, and later versions generate .sns files.

Each file represents a single ping and contains complex amplitude and phase data as 16-bit values, and optionally GPS and/or heading and/or roll data. If you wish to add multiple files to a fileset you must name them in such a way that an alphabetical sorting of the file names will sort them into date/time order.

If ping date and time are not recorded in the header data, Echoview will assign a date and time to the ping based on the file properties. This will be the earlier of the file-created or file-modified dates and times.

The data files contain 16 bit values for magnitude and phase of the returned signal (voltage) - these can be exported as underlying data. The magnitude already has a time varied gain applied to it. The voltages are converted to Sv as follows:

Sv = 20log(V) - T * log(R) + 20log(R) + C

Where:

V is the 16 bit voltage read from the snapshot file,
R is the range of the data point,
T is TVG_Spread / 4, where TVG_Spread is read from the data file and is typically 80, 120 or 160.
C is the CalibrationOffset (specified on the Calibration page of the Variable Properties dialog box, this is set by an ECS file).

Phase value is 2Pi * <value>/2^16 (radians).

If roll data is recorded in the data file Echoview will provide a roll variable. Echoview will also provide a position variable from GPS data, and an attitude variable from heading data if available.