LSD PQSL 2015 (Nov) Hydrographic Survey - HKIS
Transcript of LSD PQSL 2015 (Nov) Hydrographic Survey - HKIS
LSD PQSL Series 2015Hydrographic Survey
Speaker: Sr CHAN Kai‐hong
COMPETENCE AREAS Sounding surveys Hydrographic instrumentation and calibration Satellite positioning and navigation Marine geodesy Marine charting Maritime boundaries Local and international laws of the sea
Hydrographic Survey
Reference Standard: IHO Standard for Hydrographic Surveys (S‐44)
http://www.iho.int/iho_pubs/standard/S‐44_5E.pdf
Land Information New Zealand: Contract Specifications for Hydrographic Surveys http://www.linz.govt.nz/sea/charts/hydrographic‐standards‐technical‐specifications#sthash.HFzhveS2.dpufhttp://www.linz.govt.nz/sea/charts/hydrographic‐standards‐technical‐specifications
National Oceanic and Atmospheric Administration (NOAA) : Hydrographic Surveys Specifications and Deliverables and Field Procedures Manualhttp://www.nauticalcharts.noaa.gov/hsd/fpm/fpm.htm
Sounding Surveys
Echo Sounding Elements and Concept Errors Calibration
Position Vertical Datum Horizontal Datum
Sounding Surveys
Echo sounding by Sound Wave Frequency (High 200k‐350k vs. Low 33k) Single Beam and Multibeam Raw Data vs. Reduced Data Tide, Sound Velocity, Position
Sounding SurveysSounding Elements
Sounding depth = Time x Velocity The velocity of sound in seawater depends on pressure (hence depth), temperature (a change of 1 °C ~ 4 m/s), and salinity (a change of 1 ~ 1 m/s)
Sounding SurveysSounding Elements
Sounding SurveysSingle Beam Echo Sounding (SBES)
Sounding surveysMultiBeam Echo Sounding (MBES)
Sounding SurveysSounding Errors (Vertical)
MBES measurements MBES beamwidth Vessel’s Motion: Heave, Roll & Pitch Sound speed Draft / Draught Tidal level
Sounding surveysSounding Errors (Horizontal)
MEBS measurements Beamwidth Sound speed Vessel’s Motion: Roll & Pitch Heading GNSS receiver Instrument offset Instrument Angular Misalignment Instrument Latency
How the sounding errors are eliminated: Vessel’s Motion (Pitch, Roll and Heave) ‐ by compensation using motion sensor
Instrument Angular Misalignment (Pitch, Roll and Yaw) ‐by calibration with Patch Test
Instrument Latency ‐ by calibration with Patch Test Draft ‐ by correction with field measurement Sound Velocity ‐ by correction with field measurement
Sounding SurveysSounding Errors
Compensation: Types of Motion Sensor An inertial measurement unit, or IMU, is anelectronic device that measures and reports on acraft's velocity, orientation, and gravitationalforces, using a combination of accelerometers andgyroscopes. (for Multi‐beam Echo Sounder)
Heave Sensor (for Single‐beam Echo Sounder)
Sounding SurveysSounding Errors
Calibration: Patch Test Bar Check
Correction: Use velocity meter to measure the actual sound velocity profile for correction
Sounding SurveysSounding Errors
Types of uncertainty: Total Vertical Uncertainty (TVU) Total Horizontal Uncertainty (THU) Total Propagated Uncertainty (TPU)
Sounding SurveysUncertainties for Depth Accuracy
The calibration or patch test is an essential procedure which consists of determining the composite offset angles or angular misalignment (pitch, roll and yaw) for both transducer and motion sensor and the latency from the positioning system.
http://www.iho.int/iho_pubs/CB/C‐13/english/C_13_Chapter_3_December2010.pdf(see paragraph 5.2.1.5 Installation and calibration (patch test))
Hydrographic Instrumentation and Calibration
Pitch Test is conducted by running two pairs of reciprocal survey lines at the same speed over a sloping seafloor.
Hydrographic Instrumentation and Calibration ‐ Pitch Test
Hydrographic Instrumentation and Calibration ‐ Pitch Test
Roll Test is conducted by running a pair of reciprocal survey lines, at the same speed, in a regular and flat seafloor.
Hydrographic Instrumentation and Calibration ‐ Roll Test
Hydrographic Instrumentation and Calibration ‐ Roll Test
Yaw Test is conducted by running two adjacent pairs of reciprocal lines, at the same speed, in an area with a well defined bathymetric feature.
Hydrographic Instrumentation and Calibration ‐ Yaw Test
Latency Test is conducted by running two pairs of survey lines at different speeds over a sloping seafloor
Hydrographic Instrumentation and Calibration ‐ Latency Test
Hydrographic Instrumentation and Calibration ‐ Sound Speed Correction
Use velocity meter to measure the actual sound velocity profile for correction
DGPS (e.g. Kau Yi Chau station by Marine Department) Worldwide DGNSS: Correction Service accuracy is the same anywhere in the world. (e.g. C‐Nav)
Satellite Positioning and Navigation
Marine Geodesy
Observed Depth ‐ Tide = Charted Depth
Chart Datum (CD) of Hong Kong It is approximately the level of Lowest Astronomical Tide (LAT) LAT = lowest tide level to occur under average meteorological
conditions and under any combination of astronomical conditions. LAT was reduced from tidal observations. CD of Hong Kong adopted the LAT reduced from the tidal observations
taken during 1887, 1888, 1889. Such LAT has been adopted as the zero point for Hong Kong Tide
Tables since 1917. LAT is adopted as Chart Datum by the International Hydrographic
Organization (IHO)‐ http://www.iho.int/iho_pubs/misc/M3‐E‐OCT14.pdf (A2.5)
Marine Geodesy
Geodetic Datum Horizontal Datum
WGS 1984 HK80 Geodetic Datum HK80 Grid System
Projection: Transverse Mercator Projection
Marine Geodesy
International Convention for the Safety of Life at Sea (SOLAS) http://www.imo.org/About/Conventions/ListOfConventions/Pages/International‐Convention‐for‐the‐Safety‐of‐Life‐at‐Sea‐%28SOLAS%29,‐1974.aspx
SOLAS regulations related to Hydrographic Survey and Charting: Regulation 9 : Hydrographic Services Regulation 19 : Carriage requirements for shipborne navigational
systems and equipment Regulation 27 : Nautical charts and nautical publications Annex 3 : Nautical charts and publications Annex 14 : Electronic charts https://mcanet.mcga.gov.uk/public/c4/solasv/index.html
Marine Charting
Marine Charting
Marine Charting
Paper Nautical Charts http://www.hydro.gov.hk/eng/papercharts.php
Electronic Navigational Charts https://www.hydro.gov.hk/eng/ENCWeb/www/aboutenc.php
Hong Kong Charts
Marine Charting
Specifications of the Charts
Produced in accordance with the specifications ofthe International Hydrographic Organization (IHO)
Positions are referred to the World Geodetic System1984 (WGS84) Datum.
Depths are in metres and are reduced to the ChartDatum, which is approximately the LowestAstronomical Tide.
• Paper Nautical Charts
• Produced in 5 different scales according to their coverage and usage :
1 : 8,000HK0801HK0802HK0803
1 : 15,000HK1501HK1502HK1503HK1504
1 : 25,000HK2501HK2502
1 : 30,000HK3001HK3002
1 : 75,000HK7501
Marine Charting
Marine Charting
Hong Kong Electronic Navigational Charts.
Produced according to the International Hydrographic Organization (IHO) Transfer Standard for Digital Hydrographic Data Specification (S‐57) edition 3.1.
15 Cells covering the whole of Hong Kong waters.
Marine Charting
United Nations Convention on the Law of the Sea (UNCLOS)
http://www.un.org/depts/los/convention_agreements/texts/unclos/unclos_e.pdf
Maritime Boundaries, Local and International Law of Seas
Boundary of the Hong Kong Special Administrative Region http://www.gov.cn/gongbao/shuju/1997/gwyb199723.pdf http://www.legislation.gov.hk/blis_pdf.nsf/6799165D2FEE3FA94825755E0033E532/1EA3
A94829E27D96482575EF0028F9F4/$FILE/CAP_2207_e_b5.pdf
Maritime Boundaries, Local and International Law of Seas
Boundary of the Hong Kong Special Administrative Region
Maritime Boundaries, Local and International Law of Seas
The End