Singlebeam raw files

Singlebeam raw files

Singlebeam raw files

Singlebeam raw files (.bot, .idx, .raw)

Equipment Used: NOAA Ship Okeanos Explorer is equipped with a 26 kilohertz (kHz) Kongsberg EM 304 MKII multibeam sonar. The nominal transmit (TX) alongtrack beamwidth is 0.5°, and the nominal receive (RX) acrosstrack beamwidth is 1.0°. The system generates a 150° beam fan, containing 512 beams with up to 800 soundings per ping cycle when in high-density mode. In waters shallower than approximately 3,300 m the system is able to operate in dual-swath mode, where one nominal ping cycle includes two swaths, resulting in up to 1,600 soundings. Data are recorded using Kongsberg's Seafloor Information System (SIS) software. Collocated to the bathymetric data, bottom backscatter data were collected and stored within the raw files, both as beam-averaged backscatter values, and as full-time series values (snippets) within each beam. During standard data acquisition, the EM 304 multibeam sonar is synchronized with the other active sonars using the Kongsberg Synchronization Unit with the EM 304 multibeam sonar set as the master. Any changes in equipment setup for the year or expedition are detailed in the annual Readiness Report or associated Expedition Report, respectively. For general information about sub-bottom operations, please refer to the NOAA Ocean Exploration Mapping Procedures Manual. Calibrations: At the beginning of each field season, a multibeam geometric calibration (patch test) is conducted to resolve any angular misalignments of the EM 304 multibeam equipment. A patch test is also conducted if any multibeam equipment (e.g., transducers, IMU, antennas) is installed or disturbed. The patch test determines if there are any residual biases or errors in navigation timing, pitch, roll, and heading/yaw (and resolves each bias individually in that order). Whenever possible (and assuming reasonable values), the results of each test are applied in SIS prior to data collection for the following test. Calibration Reports are archived as supplemental documents to the annual Readiness Report throughout the year. A relative backscatter correction was performed in 2021, and the resulting gain values were uploaded to the processing unit. This procedure helps to normalize differences in backscatter values resulting from variable frequencies and pulse durations employed within sectors and among ping modes used during multibeam data acquisition. Acquisition Corrections: Real-time corrections to the data upon acquisition include the continuous application of surface sound speed obtained with a hull-mounted Reson SV-70 probe, and application of water column sound speed profiles obtained with Sippican Deep Blue Expendable Bathythermographs (XBTs) and/or Seabird CTD 9/11. Sound speed profiles are conducted every four hours, or more frequently as dictated by local oceanographic conditions (typically every two hours when operating in more dynamic areas). Reson sound speed values are constantly compared against secondarily derived sound speed values from the ship’s onboard thermosalinograph flow-through system as a quality assurance measure. Roll, pitch, and heave motion corrections are applied in real-time via a POS MV 320 version 5 or a Seapath-380, using Marine Star DGPS correctors. The motion and positioning unit used will be noted in the processing logs. No tidal corrections are applied to the raw or processed data. Multibeam data quality is monitored in real-time by acquisition watchstanders. Ship speed is adjusted to maintain data quality and sounding density as necessary. Line spacing is planned to ensure one-quarter to one-third swath-width overlap between lines, depending on the environmental conditions and impact on the quality of the outer swath regions. Angles are generally left open (70°/70°) during transits to maximize data collection and are adjusted on both the port and starboard sides to ensure the best data quality and coverage. If outer beams are returning obviously spurious soundings (e.g., due to attenuation or low

The 2021 North Atlantic Stepping Stones: New England and Corner Rise Seamounts expedition (EX-21-04) was a combined mapping and remotely operated vehicle (ROV) expedition to the seamounts of the Northwest Atlantic that took place between June 30 and July 29, 2021. Operations during this 30-day at sea expedition included a combination of ROV dives in support of NOAA Ocean Exploration and its partner priorities as well as exploratory mapping operations targeting areas containing no or poor quality modern mapping data. The initial focus was on the U.S. Northeast Seamount and high seas areas, however, during the expedition weather altered the planned transect to outside Bermudan waters where three dives took place before rejoining the planned dive sites exploring a total of 19 seamounts and one canyon (Hydrographer) for water column exploration. During the expedition, 20 Deep Discoverer ROV dives were conducted from 300 m to 4187 m water depth for a total of 154 hours of bottom time, and surveyed using EM 304 multibeam sonar 54,710 square km over 30 days at sea. All data associated with this expedition have been archived and are publicly available through the NOAA Archives.

During EX2402, acoustic data were collected with the ship's EM 304 multibeam data (26 kHz), Knudsen 3260 sub-bottom profiler (3.5 kHz), the suite of five EK60/80 split-beam sonars (18, 38, 70, 120, and 200 kHz), and two ADCPs (38 and 300 kHz). More information about equipment used and methods employed can be found in the annual readiness report.

From February 23 - March 3, 2022 (Pascagoula, MS to Key West, FL), NOAA Ocean Exploration conducted a shakedown of the remotely operated vehicle (ROV), video, telepresence, and sampling operations as well as mapping and positioning systems aboard NOAA Ship Okeanos Explorer. The ROV engineers tested and calibrated ROVs Deep Discoverer and Seirios' ROV motor controllers, auto position software, lighting system, hydraulic system, ME-20 low-light camera, high-definition ancillary ROV cameras, sector-scanning sonar, as well as tested remote-piloting capabilities of ROV Deep Discoverer. Shakedown and readiness operations for the EM 304 multibeam sonar included a GNSS Azimuth Measurement Subsystem (GAMS) calibration, Patch Test, speed-noise test, coverage extinction data collection, and integration and testing of the newly installed SeaPath 380-R3. In total, the expedition team conducted 7 ROV dives ranging from 480 to 3,420 m depth and collected 4,930 square kilometers of acoustic data during transits and calibrations. The expedition explored the West Florida Shelf and the Straits of Florida offshore the U.S. southeastern coast. The expedition confirmed the location of a shipwreck target, thought to be a 19th century whaler. Corals and sponges were observed 4 out of the 7 surveyed dive sites, with 3 of the 7 containing high diversities of benthic species. A total of 12 samples were collected: 3 geological, 3 biological, and 6 commensal (not including blank samples).

Singlebeam raw files (.bot, .idx, .raw)

Singlebeam raw files (.bot, .idx, .raw)