Metadata Report for BODC Series Reference Number 1108916


Metadata Summary

Data Description

Data Category Platform orientation and velocity
Instrument Type
NameCategories
Ashtech GG24 Global Positioning System and Global Navigation Satellite System receiver  Global Navigation Satellite System receivers; NAVSTAR Global Positioning System receivers
Ashtech ADU5 Global Positioning System receiver  Differential Global Positioning System receivers
Kongsberg Seatex Seapath 200 Global Positioning System receiver and Gyrocompass  platform attitude sensors; Differential Global Positioning System receivers
Furuno GP32 Global Positioning System receiver  NAVSTAR Global Positioning System receivers
Instrument Mounting research vessel
Originating Country United Kingdom
Originator Dr Rachael Shreeve
Originating Organization British Antarctic Survey
Processing Status QC in progress
Project(s) DISCOVERY 2010
 

Data Identifiers

Originator's Identifier JR20061024-PRODQXF_NAV
BODC Series Reference 1108916
 

Time Co-ordinates(UT)

Start Time (yyyy-mm-dd hh:mm) 2006-10-23 23:59
End Time (yyyy-mm-dd hh:mm) 2006-11-28 23:57
Nominal Cycle Interval 60.0 seconds
 

Spatial Co-ordinates

Start Latitude 52.25650 S ( 52° 15.4' S )
End Latitude 50.03580 S ( 50° 2.1' S )
Start Longitude 57.14160 W ( 57° 8.5' W )
End Longitude 38.14950 W ( 38° 9.0' W )
Positional Uncertainty 0.0 to 0.01 n.miles
Minimum Sensor Depth -15.0 m
Maximum Sensor Depth -15.0 m
Minimum Sensor Height -
Maximum Sensor Height -
Sea Floor Depth -
Sensor Distribution Fixed common depth - All sensors are grouped effectively at the same depth which is effectively fixed for the duration of the series
Sensor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
Sea Floor Depth Datum Instantaneous - Depth measured below water line or instantaneous water body surface
 

Parameters

No Parameters for BODC Reference Number = 1108916

 

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


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

Ashtech GG24 receiver

The GG24 is an all-in-view Global Positioning System (GPS) and Global Navigation Satellite System (GLONASS) receiver that blends GPS and GLONASS into a single position solution. This receiver uses all available satellites from both systems to obtain the best position information.

The three-dimensional position and velocity are calculated when tracking any combination of five satellites. Up to five independent measurements are determined every second, with no interpolation or extrapolation from previous solutions.

Specifications

Parameter Values
Operating Temperature -30°C to 55°C
Sampling frequency up to 5 Hz
Receiver channels 12 L1 GPS + 12 L1 GLONASS
Real-Time Position Accuracy

3.2 m (autonomous)

35.0 m (differential)

Velocity Accuracy 0.1 knots

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

Ashtech Global Positioning System receivers (ADU series)

The ADU series of Global Positioning System (GPS) receivers are designed to give real-time three-dimensional position and attitude measurements. Attitude determination is based on differential carrier phase measurements between four antennas connected to a receiver, providing heading, pitch and roll, along with three-dimensional position and velocity.

The ADU2 model receives information from 48 channels, while the upgraded model (ADU5) uses 56 channels. The ADU5 also features a unique Kalman filter with user selectable dynamic modes to match operating conditions. It also incorporates signals from Satellite Based Augmentation Systems (SBAS) and features an embedded 2-channel 300 kHz beacon receiver for easy differential GPS (DGPS) operations.

Specifications

Parameter ADU2 ADU5

Operational Temperature range:
Antenna
Receiver


-40°C to 65°C
-20°C to 55°C


-40°C to 65°C
-20°C to 55°C

Sampling frequency 5 Hz 5 Hz
Receiver channels 48 56

Accuracy:
Heading
Pitch/Roll


0.2° rms (dynamic) - 0.4° rms (static)
0.4° rms (dynamic) - 0.8° rms (static)


0.02° to 0.2° rms
0.04° to 0.4° rms

Circular Error Probability:
Autonomous
Differential


5.0 m
1.0 m


3.0 m
0.4 to 1.0 m

Further details can be found in the manufacturer's specification sheets for the ADU2 and ADU5 .

Furuno GPS/WAAS Navigator GP32

The GP32 is an advanced GPS navigator with a Wide Area Augmentation System (WAAS) receiver which can receive up to 12 discrete GPS channels, all-in-view, and also has DGPS capabilities.

The WAAS applies correction data by means of geostationary satellites. The reference stations on earth monitor the GPS constellation and route GPS error data to the WAAS satellite via the master earth station.

This equipment is comprised of a compact unit designed for coastal activities with several display modes, e.g. Plotter, Nav Data, Steering, Highway, Speedometer and two other costumisable modes. The data can be viewed in WGS-84 or other geodetic systems.

Specifications

GPS/WAAS
Receiver type

GPS: 12 discrete channels, C/A code, all-in-view

WAAS: standard fitted display unit

Receive frequency L1 (1575.42 MHz)
Time to first fix 12 s (typical)
Tracking velocity 999 knots
DGPS
Reference stations Automatic or manual selection
Frequency range 283.5 to 325 kHz in 0.5 kHz steps
Accuracy
GPS 10 m (95%)
DGPS 5 m (95%)
WAAS 3 m (95%)

The equipment's specification sheet can be accessed Furuno GP32

Kongsberg Seatex Seapath 200 GPS and Gyrocompass

The Seapath 200 is a highly accurate, real-time heading, attitude and position information system that integrates the best signal characteristics of Inertial Measurement Units (IMU) and Global Positioning System (GPS), using a differential GPS method to acquire this data.

The high-rate motion data is obtained from the Seatex MRU5 inertial sensor and two fixed baseline GPS carrier-phase receivers. The raw data is integrated in a Kalman filter in the Seapath Processing Unit. The IMU contains an accurate linear accelerometer and Bosch Coriolis force angular rate gyros (CFG).

This system is equipped to utilise up to six different DGPS reference stations, it checks for consistency within measurements from the different sensors to ensure reliability and rejects noisy data or reports its inaccuracy. The data is available through various output protocols, RS-232, RS-422 and Ethernet.

This instrument is no longer in production; the main characteristics are presented below, and the specification sheet can be accessed here Kongsberg Seatex Seapath 200 .

Specifications

Scale factor error in pitch, roll and heading 0.2% RMS
Heave motion periods 1 to 25 s
Accuracy
Heading

0.05° RMS (4 m baseline)

0.075° RMS (2.5 m baseline)

Roll and Pitch 0.03° EMS (± 5° amplitude)
Heave 5 cm or 5%, whichever is highest
Position

0.7 RMS or 1.5 m (95% CEP) with DGPS

0.15 m EMS or 0.4 m (95% CEP) with Searef 100 corrections

Velocity 0.03 m s -1 RMS or 0.07 m s -1 (95% CEP) with DGPS

DISCOVERY2010 James Clark Ross Cruise JR20061024 (JR161) Navigation Document

Cruise details

Dates 2006-10-24 to 2006-12-03
Principal Scientific Officer Rachael Shreeve, British Antarctic Survey
Data supplied by Hugh Venables, Nathan Cunningham, British Antarctic Survey

Cruise JR20061024 (JR161) was conducted within the Scotia Sea as part of the DISCOVERY 2010 BAS program. Three transects were run as follows:

1- From Stanley in the Falkland Islands, to Signy in the South Orkneys

2- From Signy towards the Polar Front North of the Island of South Georgia

3- From the Polar front back to Stanley

The cruise strategy included samples and measurements to characterise the oceanography, nutrients, phytoplankton, zooplankton, fish and higher predators. Some of the planned sampling events had to be cancelled due to operational delays related with staff relief at Signy and the occasional bad weather.

Fully processed data covering a period from 24 October 2006 to 28 November 2006 was received at BODC in a single file, with time supplied in UT.

The data set is shorter than expected as it was trimmed during the processing stages carried out by the originator. The ship navigated in and out of the ice region in several periods and most of these were deleted from the final file. Data from the anemometer were logged but because it was considered of poor quality, it was decided, during the processing stages performed by the originator, that it should not be included in the final file.

Content of data series

Parameter Units Parameter code Comments
Latitude degrees ALATGP01 -
Longitude degrees ALONGP01 -
Distance travelled Km DSRNCV01 derived from ALATGP01 and ALONGP01

Instrumentation

Navigation data was obtained from the following data streams:

Instrument Type Manufacturer Main role
Ashtech ADU5 GPS Ashtech Antenna 1 used to determine the ships' position, antennae 2-4 used to determine roll, pitch and yaw
GLONASS GG24 GPS Ashtech Positional information
Seapath GPS200 GPS Seatex Position and heading
GPS NMEA GP32 GPS Furuno Positional information
Gyro 200 heading Gyrocompass Seapath Heading information

Data Processing Procedures

One file was received at BODC, containing fully processed data that were merged from the navigation, meteorology and oceanlogger systems. The data were sent with a 1 minute resolution. The start date was 24 October 2006 00:00 hours and end date 28 November 2006 23:58 hours.

The file contains 24 channels, and although all are available on request, not all were loaded onto BODC's database, as the data were uncalibrated or obtained from secondary sensors. Originator's variables and units are: time (seconds), time_jday (days), air_temperature1 (°c90), humidity1 (%), par1 (µmol m -2 s -1 ), tir1 (W m -1 ), air_temperature2 (°c90), humidity2 (%), par2 (µmol m -2 s -1 ), tir2 (W m -1 ), pressure1 (hPa), pressure2 (hPa), saltemp (°c90), cond (S m -1 ), psal (pss-78), sound_vel (m s -1 ), fluor (µg l -1 ), fstemp (°c90), flow (l min -1 ), sst (°c90), sst_uncal (°c90), psal_uncal (pss-78), latitude (degrees), longitude (degrees).

Originator's Data Processing

The originator's procedures encompassed two stages: the retrieval of the datastreams using Unix based scripts and processing using Matlab. Data from the different instruments were merged into one file and a visual inspection was carried out. Plots were produced to allow for checks of data completeness and integrity.

During the data analysis it was clear that the data from the gyrocompass was of poor quality so, although logging continued, the originator decided not to include it in the final processed file. The file contains information for the best position information collected during the cruise.

BODC Data Processing

Parameter codes defined in BODC's parameter dictionary were assigned to originator's variables. There was no need to apply a conversion as original units were equivalent to the ones defined in BODC codes. Data were loaded into BODC's database using established data banking procedures.

Originators' Parameter Name Units Description BODC parameter code Units
latitude degrees Latitude north (WGS84) by unspecified GPS system Method Global Positioning System (receiver type unspecified) ALATGP01 degrees
longitude degrees Longitude east (WGS84) by unspecified GPS system Method Global Positioning System (receiver type unspecified) ALONGP01 degrees
- - Distance travelled DSRNCV01 Km

Navigation was checked using the NAVCHECK routine and speed fails were identified. The cycles were identified and flagged with the absent value flag (N). NAVINT was then used to interpolate data for these gaps and later confirmed that they were successfully applied. No other flags were applied to these channels.

DISRUN was also used to compute the distance travelled during the cruise. A new channel, DSRNCV01, was created and checked graphically and no jumps or spikes were identified.

Quality control report

T flags were assigned to the interpolated values created with NAVINT, the corresponding cycles are: 1283 to 1289 and 31919 to 31944.


Project Information

DISCOVERY 2010

DISCOVERY 2010 will investigate and describe the response of an ocean ecosystem to climate variability, climate change and commercial exploitation. The programme builds on past studies by BAS on the detailed nature of the South Georgia marine ecosystem and its links with the large-scale physical and biological behaviour of the Southern Ocean.

The aim is to identify, quantify and model key interactions and processes on scales that range from microscopic life forms to higher predators (penguins, albatrosses, seals and whales), and from the local to the circumpolar.

Objectives

Assess the links between the status of local marine food webs and variability and change in the Southern Ocean. Develop a linked set of ecosystem models applying relevant marine physics and biology over scales from the local to that of the entire Southern Ocean.

Relevance to Global Science

Ocean ecosystems play a crucial role in maintaining biodiversity, in depositing carbon into the deep ocean, and as a source of protein for humans. However, fishing and climate change are having significant and often detrimental effects. To predict the future state of ocean ecosystems we must develop computer models capable of simulating biological and physical processes on a range of scales from the local to an entire ocean. Developing such predictive models is crucial to the sustainable management of world fisheries and requires integrated analyses of the way whole ecosystems work. DISCOVERY 2010 aims to take this work forward and at the same time help manage the South Georgia and South Sandwich Islands maritime zone. We will do this through providing information on the state of the ecosystem to the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), the international body that manages sustainable fishing in the Southern Ocean.

Delivering the Results

DISCOVERY 2010 will undertake an integrated programme of shipboard and land-based field studies of the marine food web, combined with modelling. We will pay particular attention to critical phases in the life cycles of key species, and to examining interactive effects in food webs. Interacting biological and physical processes will be modelled across a range of spatial scales to significantly improve our representation of the ocean ecosystem, upon which sustainable management and the prediction of future climate change can be based. DISCOVERY 2010 will link to BIOFLAME, ACES, and COMPLEXITY, two international programmes, and to a collaborative programme with the University of East Anglia on the role of the Southern Ocean in the global carbon cycle.

Component Projects


Data Activity or Cruise Information

Cruise

Cruise Name JR20061024 (JR156, JR161)
Departure Date 2006-10-24
Arrival Date 2006-12-03
Principal Scientist(s)Rachael Shreeve (British Antarctic Survey)
Ship RRS James Clark Ross

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