Metadata Report for BODC Series Reference Number 1762261


Metadata Summary

Data Description

Data Category Bathymetry
Instrument Type
NameCategories
Kongsberg (Simrad) EA600 Echosounder  single-beam echosounders
Trimble Applanix POSMV global positioning system  Differential Global Positioning System receivers; inertial navigation systems; Kinematic Global Positioning System receivers
Kongsberg Seatex Differential Positioning Sensor 116  Differential Global Positioning System receivers
Sperry Marine NAVIGAT X MK 1 digital gyrocompass  platform attitude sensors
Instrument Mounting research vessel
Originating Country United Kingdom
Originator Mr Martin Bridger
Originating Organization National Marine Facilities Sea Systems
Processing Status banked
Project(s) Oceans 2025 Theme 10 SO1:AMT
 

Data Identifiers

Originator's Identifier JC079_PRODQXF_CHLAUPDATED_NAV
BODC Series Reference 1762261
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2012-10-10 08:00
End Time (yyyy-mm-dd hh:mm) 2012-11-20 20:01
Nominal Cycle Interval 60.0 seconds
 

Spatial Co-ordinates

Southernmost Latitude 47.14983 S ( 47° 9.0' S )
Northernmost Latitude 50.89183 N ( 50° 53.5' N )
Westernmost Longitude 54.82633 W ( 54° 49.6' W )
Easternmost Longitude 1.29167 W ( 1° 17.5' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor Depth -
Maximum Sensor Depth -
Minimum Sensor Height -
Maximum Sensor Height -
Sea Floor Depth -
Sensor Distribution -
Sensor Depth Datum -
Sea Floor Depth Datum -
 

Parameters

BODC CODE Rank Units Short Title Title
AADYAA01 1 Days Date(Loch_Day) Date (time from 00:00 01/01/1760 to 00:00 UT on day)
AAFDZZ01 1 Days Time(Day_Fract) Time (time between 00:00 UT and timestamp)
ALATGP01 1 Degrees Lat_GPS Latitude north (WGS84) by unspecified GPS system
ALONGP01 1 Degrees Lon_GPS Longitude east (WGS84) by unspecified GPS system
APEWGP01 1 Centimetres per second PlatformVelE_GPS Eastward velocity (over ground) of measurement platform by unspecified GPS system
APNSGP01 1 Centimetres per second PlatformVelN_GPS Northward velocity (over ground) of measurement platform by unspecified GPS system
DSRNCV01 1 Kilometres Cmpval Distance travelled
HEADCM01 1 Degrees Platform_Heading Orientation (horizontal relative to true north) of measurement device {heading}
MBANCT01 1 Metres BathyDepESCartCorr Sea-floor depth (below instantaneous sea level) {bathymetric depth} in the water body by echo sounder and correction using Carter's tables
 

Definition of Rank

  • Rank 1 is a one-dimensional parameter
  • Rank 2 is a two-dimensional parameter
  • Rank 0 is a one-dimensional parameter describing the second dimension of a two-dimensional parameter (e.g. bin depths for moored ADCP data)

Problem Reports

No Problem Report Found in the Database

AMT RRS James Cook Cruise JC079 AMT22 Navigation and Bathymetry Data Quality Document

The navigation data have been through BODC quality control screening. The 15 gaps of less than ten minutes have been filled by interpolation. Overall the data for the cruise duration appear good.

The bathymetric data have been through BODC quality control screening. There are periods of noise that hide the real bathymetry in the channel. Where possible some periods have been flagged to remove the noise. Users should use caution when interpreting the bathymetric depth channel.


Data Access Policy

Open Data supplied by Natural Environment Research Council (NERC)

You must always use the following attribution statement to acknowledge the source of the information: "Contains data supplied by Natural Environment Research Council."


Narrative Documents

Kongsberg EA600 Single Beam Echosounder

The EA600 is a single beam echosounder with full ocean depth capability designed for bathymetric surveys. It measures water depth by monitoring the travel time of an acoustic signal that is transmitted from the ship, reflected off the seabed and received back at the ship.

The main components of the system are hull-mounted transducers linked to general purpose transceivers (GPTs). Up to four GPTs, each controlling one or more transducers, may be operated simultaneously. The GPT generates a signal, which is transmitted into the water column as an acoustic pulse by the transducer array, and the returning echo is recorded by the GPT. GPTs are in turn linked to a combined display and processor, where adjustments (such as sound-speed corrections) may be applied to the data. Available frequencies span from 12 to 710 kHz, and each GPT may operate at a separate frequency. A variety of transducers is available for water depths up to 11,000 m.

The EA600 stores all data internally but has a USB port which allows the possibility of connecting a CD-ROM/DVD drive to read and write the data. All echo data can be stored as files: bitmap, sample, depth or sidescan data.

In deeper waters, the EA600 supports a multipulse function, allowing for a higher pinger rate. While on passive mode, the pinger is normally attached to a device, with the purpose of tracking and displaying its current depth.

The EA600 replaced the EA500 in 2000.

Specifications

Maximum Ping rate 20 Hz
Resolution 1 cm
Accuracy

1 cm at 710 and 200 kHz
2 cm at 120 kHZ
5 cm at 38 kHz
10 cm at 18 kHz
20 cm at 12kHz

Operating frequencies 1 or 2 kHz
Single Beam frequencies

12, 18, 33, 38, 50, 70,
120, 200, 210 or 710 kHz

Dynamic range 160 dB

Further details can be found in the manufacturer's specification sheet .

AMT RRS James Cook Cruise JC079 AMT22 Navigation and Bathymetry Instrument Description Document

Sensor Serial number Last calibration date Deployment
Gill Wind sonic (Option 3) 064537 - Starboard
Skye Instruments SKE510 28560 2011-07-05 Starboard
Skye Instruments SKE510 28561 2011-07-11 Port
Kipp and Zonen Ltd CMB6 973134 2011-07-15 Starboard
Kipp and Zonen Ltd CMB6 973135 2011-07-15 Port
Vaisala PTB100A U1420016 2012-03-26 Starboard
Vaisala HMP45A E1055002 2012-07-02 Starboard

Kongsberg Seatex Differential Positioning Sensor 116

A 14-channel, all-in-view, L1 GPS receiver which primarily utilises the free, WAAS, EGNOS and MSAS Satellite Based Augmentation Systems (SBAS) for differential corrections (DGPS). It is also capable of simultaneous DGPS from a wide variety of other reference stations (Multiref), resulting in improved accuracy. Simultaneous reception and use of correction signals in MF and UHF frequency bands, Inmarsat standard A, B and M terminals and SeaSTAR Spot, are possible.

Performance  
DGPS position accuracy with SBAS service < 1.5 m, 95% CEP (*)
0.6 m, 1θ (*)
DGPS position accuracy (Multiref) < 1 m, 95% CEP (**)
0.4 m, 1θ (**)
Velocity accuracy 0.05 m/s, 95% CEP (**)
0.02 m/s, 1θ (**)
Output rate 1 Hz

(*) Accuracy specifications are based on real-life tests conducted using WAAS and an open view to the sky in Houston, Texas.

(**) Accuracy specifications are based on real-life tests conducted under low multipath conditions and an open view to the sky in Trondheim, Norway. Tests at different locations under different conditions may produce different results.

Full specifications can be found here .

Sperry Marine NAVIGAT X MK 1 digital gyrocompass

A digital gyrocompass for use in marine navigation. The system comprises a gyrosphere supported in fluid, suspended at a single point. The centering pin retaining arrangement can be mounted in an additional gimbal system for high speed applications (Mod 7). The system can drive up to 12 analogue repeaters and has 7 independent serial outputs and 2 dependent 6 steps/° heading outputs. The NAVIGAT X MK1 was the first of the Sperry Marine range of heading sensors, which comprises the NAVIGAT 3000 fibreoptic gyrocompass, the NAVIGAT X MK 1 and the NAVIGAT X MK 2 digital gyrocompasses.

Specifications

Heading accuracy <0.1° secant latitude (linear mean settle point error)
<0.1° secant latitude (static)
<0.4° secant latitude (dynamic)
Freedom of pitch and roll ±40° (Mod 10)
±90° (Mod 7)

Detailed specifications can be found in the manufacturer's data sheet .

Trimble Applanix Position and Orientation Systems for Marine Vessels (POSMV)

The Position and Orientation Systems for Marine Vessels (POSMV) is a real time kinematic (RTK) and differential global positioning system (DGPS) receiver for marine navigation. It includes an inertial system that provides platform attitude information. The instrument provides accurate location, heading, velocity, attitude, heave, acceleration and angular rate measurements.

There are three models of Applanix POSMV, the POS MV 320, POS MV Elite and the POS MV WaveMaster. POS MV 320 and POS MV WaveMaster are designed for use with multibeam sonar systems, enabling adherence to IHO (International Hydrographic Survey) standards on sonar swath widths of greater than ± 75 degrees under all dynamic conditions. The POS MV Elite offers true heading accuracy without the need for dual GPS installation and has the highest degree of accuracy in motion measurement for marine applications.

Specifications

POS MV 320
Componenet DGPS RTK GPS Outage
Position 0.5 - 2 m 1 0.02 - 0.10 m 1 <2.5 m for 30 seconds outages, <6 m for 60 seconds outages
Roll and Pitch 0.020° 0.010° 0.020°
True Heading 0.020° with 2 m baseline
0.010° with 4 m baseline
- Drift <1° per hour (negligible for outages <60 seconds)
Heave 5 cm or 5% 2 5 cm or 5% 2 5 cm or 5% 2
POS MV WaveMaster
Accuracy DGPS RTK GPS Outage
Position 0.5 - 2 m 1 0.02 - 0.10 m 1 <3 m for 30 seconds outages, <10 m for 60 seconds outages
Roll and Pitch 0.030° 0.020° 0.040°
True Heading 0.030° with 2 m baseline - Drift <2° per hour
Heave 5 cm or 5% 2 5 cm or 5% 2 5 cm or 5% 2
POS MV Elite
Accuracy DGPS RTK GPS Outage
Position 0.5 - 2 m 1 0.02 - 0.10 m 1 <1.5 m for 60 seconds outages DGPS, <0.5 m for 60 seconds outage RTK
Roll and Pitch 0.005° 0.005° 0.005°
True Heading 0.025° 0.025° Drift <0.1° per hour (negligible for outages <60 seconds)
Heave 3.5 cm or 3.5% 2 3.5 cm or 3.5% 2 3.5 cm or 3.5% 2

1 One Sigma, depending on quality of differential corrections
2 Whichever is greater, for periods of 20 seconds or less

Further details can be found in the manufacturer's specification sheet.

AMT RRS James Cook Cruise JC079 AMT22 Navigation and Bathymetry Processing Procedures Document

Originator's Data Processing

During the cruise there was a dual logging system in place on the RRS James Cook. Data from the various instruments were logged to the RVS Level-C system and also as NetCDF (binary) through the Ifremer Techsas data logging system. The following instruments were logged during the cruise:

1) Applanix POS MV DGPS (logged to RVS format as posmvpos)
2) C-Nav 300 DGPS (logged to RVS format as gps_cnav)
3) Kongsberg Seatex DPS116 DGPS (logged to RVS format as dps116)
4) Chernikeef EM speed log (logged to RVS format as log_chf)
5) Ship's Gyrocompass (logged to RVS format as gyro_s)
6) Simrad EA600 Precision Echo Sounder (logged to RVS format as ea600m)

Processing was carried out using the RVS software suite. The following routines were run on the navigation and bathymetry data channels to produce files named after the routine that generated them:
RELMOV - Relmov is the relative motion file for this cruise. This was generated using the ships gyro and ships Chernikeef Log data to extract a movement in a given direction. This was then used by bestnav when and where necessary to calculate fixes if GPS fixes were not available.
BESTNAV - Bestnav uses all 3 GPS Systems logged and creates a best suite stream by providing an as complete account of the ships track as possible. This is done by reading all 3 GPS streams with posmvpos being primary, gps_cnav as secondary and dps116 as tertiary. The system looks for gaps of a certain length in the primary and when it finds those gaps it requests that the next gps down fill in the gaps. If no GPS data is available it asks RELMOV to fill in until data is available again. Then the system calculates back over itself to ensure that the extrapolated positions are correct using the GPS data available around the gap.
BESTDRF - Bestdrf is a product of bestnav. When run bestnav uses the relmov data which contains a predicted vn and ve based upon direction and speed through the water. The Bestdrf file is the accurate drift velocity of what actually occurred based on the GPS changes between each record.
PRODEP - Prodep is an automated process that accessed the bestnav position fix data and then uses a pre programmed Carter tables of corrections and corrects the echo sounder data for that given time.

The data from the BESTNAV and PRODEP routines were taken for transfer into the underway dataset.

Filename Data type Start Calendar Day Start Time Finish Calendar Day Finish Time Data Interval
bestnav RVS Level-C processed 2012-10-10 08:00:00 2012-11-20 20:00:40 10 seconds
prodep RVS Level-C processed 2012-10-10 09:05:15 2012-11-20 20:00:05 variable

BODC Data Processing

The RVS Level-C files were chosen for transfer to the BODC underway file.

The bestnav and prodep data were transferred. A description of the channels present in the files, units, whether they were transferred, BODC parameter code and units, and if a unit conversion was applied during the transfer are detailed in the table below:

bestnav Channels Description Units BODC Parameter Code Units Conversion Factor
lat Latitude Degrees +ve N ALATGP01 Degrees +ve N *1
lon Longitude Degrees +ve E ALONGP01 Degrees +ve E *1
vn Northwards velocity knots APNSGP01 cm s -1 *51.44
ve Eastwards velocity knots APEWGP01 cm s -1 *51.44
cmg Course made good Degrees True APDAGP01 Degrees True *1
smg Speed made good knots APSAGP01 m s -1 *0.514
dist_run Distance run Nautical mile DSRNCV01 km *1.852
heading Ship's heading Degrees True HEADCM01 Degrees True *1
prodep Channels Description Units BODC Parameter Code Units Conversion Factor
uncdepth Raw depth from echosounder m MBANZZ01 - To be dropped after screening m *1
cordepth Depth corrected from Carter's tables m MBANCT01 m *1
cartarea Carter's table area from position - not for transfer - -

The navigation channels were checked using BODC Matlab routine 'navcheck' and 15 gaps were identified. Each period was less than 10 minutes in duration and using the BODC Matlab routine 'navint' the gaps were filled by interpolation. There were no speed check failures.

Sample Calibrations

No calibrations were applied to these data by BODC.


Project Information

Oceans 2025 Theme 10, Sustained Observation Activity 1: The Atlantic Meridional Transect (AMT)

The Atlantic Meridional Transect has been operational since 1995 and through the Oceans 2025 programme secures funding for a further five cruises during the period 2007-2012. The AMT programme began in 1995 utilising the passage of the RRS James Clark Ross between the UK and the Falkland Islands southwards in September and northwards in April each year. Prior to Oceans 2025 the AMT programme has completed 18 cruises following this transect in the Atlantic Ocean. This sustained observing system aims to provide basin-scale understanding of the distribution of planktonic communities, their nutrient turnover and biogenic export in the context of hydrographic and biogeochemical provinces of the North and South Atlantic Oceans.

The Atlantic Meridional Transect Programme is an open ocean in situ observing system that will:

The specific objectives are:

The measurements taken and experiments carried out on the AMT cruises will be closely linked to Themes 2 and 5. The planned cruise track also allows for the AMT data to be used in providing spatial context to the Sustained Observation Activities at the Porcupine Abyssal Plain Ocean Observatory (SO2) and the Western Channel Observatory (SO10).

More detailed information on this Work Package is available at pages 6 - 9 of the official Oceans 2025 Theme 10 document: Oceans 2025 Theme 10

Weblink: http://www.oceans2025.org/


Data Activity or Cruise Information

Cruise

Cruise Name JC079 (AMT22)
Departure Date 2012-10-10
Arrival Date 2012-11-24
Principal Scientist(s)Glen A Tarran (Plymouth Marine Laboratory)
Ship RRS James Cook

Complete Cruise Metadata Report is available here


Fixed Station Information


No Fixed Station Information held for the Series


BODC Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:

Flag Description
Blank Unqualified
< Below detection limit
> In excess of quoted value
A Taxonomic flag for affinis (aff.)
B Beginning of CTD Down/Up Cast
C Taxonomic flag for confer (cf.)
D Thermometric depth
E End of CTD Down/Up Cast
G Non-taxonomic biological characteristic uncertainty
H Extrapolated value
I Taxonomic flag for single species (sp.)
K Improbable value - unknown quality control source
L Improbable value - originator's quality control
M Improbable value - BODC quality control
N Null value
O Improbable value - user quality control
P Trace/calm
Q Indeterminate
R Replacement value
S Estimated value
T Interpolated value
U Uncalibrated
W Control value
X Excessive difference

SeaDataNet Quality Control Flags

The following single character qualifying flags may be associated with one or more individual parameters with a data cycle:

Flag Description
0 no quality control
1 good value
2 probably good value
3 probably bad value
4 bad value
5 changed value
6 value below detection
7 value in excess
8 interpolated value
9 missing value
A value phenomenon uncertain