Processing Single Beam Data Overview 11212020 2006 HYPACK

Processing Single Beam Data Overview 11/21/2020 2006 HYPACK® Training Seminar 1

SINGLE BEAM EDITING FLOW Raw Data SURVEY Editing *. TID *. VEL Sounding Selection SORT SINGLE BEAM EDITOR CROSS SECTIONS & VOLUMES Edited Data 3 DTV CROSS SORT EXPORT TO CAD Sorted Data HYPLOT Final Products *. PLT TIN MODEL 11/21/2020 2006 HYPACK® Training Seminar 2

Single Beam Editor (SBMAX) Editing Single Beam Data – Determine a position and raw correctors for every depth measurement. Tide Draft Sound Velocity Heave-Pitch-Roll Raw Data SBMAX – Apply water level corrections. – Eliminate or smooth positioning errors. – Eliminate or smooth depth measurement errors. – Save each depth with associated position and correctors. *. TID *. VEL New Edited ‘All’ Format Old Edited ‘All’ Format 11/21/2020 2006 HYPACK® Training Seminar 3

New Edited ‘ALL’ Format Now tracks the following for each sounding: Event Number LF Flag WGS 84 Lat Stand. Error Z Seabed ID X (Easting) LF SV Corr. WGS 84 Long Heading Seabed Color Y (Northing) Tide Corr. WGS 84 Ell. Ht. CMG Ht of Ell. Above CD Time Draft Corr. GPS Status XTE Ht. of Ell. Ab. Geoid HF Depth Heave Corr. HDOP/PDOP DBL Total Propagated Error (TPE) HF Flag Raw Heave # of SATS Speed Checksum HF SV Corr. Raw Roll Stand. Error X Seabed E 1 LF Depth Raw Pitch Stand. Error Y Seabed E 2 11/21/2020 2006 HYPACK® Training Seminar 4

Corrections to Soundings Static Draft Dynamic Draft Heave Sound Velocity Tide (Water Level) 11/21/2020 2006 HYPACK® Training Seminar 5

Echosounder Measurements Depth Reported From Echosounder Equals Sum of: § Static Draft § Obtained by bar check. § Depth Below Transducer § Equals round trip travel time of sound wave divided by sound velocity. 11/21/2020 2006 HYPACK® Training Seminar Depth below transducer Depth reported by echosounder 6

Dynamic Draft Vertical Movement of the Transducer from its Static Position Dynamic Draft is composed of: – Settlement: Downward movement of vessel during forward movement cause by a pressure wave created in front of the vessel. Static Draft Transducder – Squat: A rotation of the vessel caused by the application of power 11/21/2020 Squat 2006 HYPACK® Training Seminar Settlement 7

Determining Changes in Dynamic Draft Use a level instrument to determine height changes in the transducer at different RPM/speeds. Run the test at slack tide to avoid the influence of currents. 11/21/2020 2006 HYPACK® Training Seminar RPM Speed Vertical Change 0 0 kts 0. 00 m 500 2. 5 kts -0. 25 m 1000 4. 5 kts -0. 30 m 2500 7. 0 kts -0. 10 m 8

Correcting for Dynamic Draft Use a pressure transducer Manually enter draft as the vessel RPM changes. Use the DRAFTTABLE driver to determine draft versus speed. – This can introduce errors when surveying into and with the current! 11/21/2020 2006 HYPACK® Training Seminar AVI Manual Entry AVI DRAFTTABLE JPG DRAFTTABLE 9

Heave Corrections Heave Vertical Reference 11/21/2020 2006 HYPACK® Training Seminar A heave sensor (or MRU) outputs its height above or below it’s current vertical reference. The vertical reference changes based on the range of motion of the sensor. 10

Heave-corrected soundings Computer MRU HPR Data Echosounder Connecting your MRU Raw soundings HPR Data Computer You can do it this way …. . We prefer you do it this way. Adding the MRU as a separate device allows you to examine the raw heave-pitch-roll data. 11/21/2020 2006 HYPACK® Training Seminar 11

Where to put the MRU? Low Dynamics (River) High Dynamics (Waves) MRU Transducer MRU The MRU can provide accurate measurements in dynamic conditions if you reduce the accelerations by placing it in the ‘center of mass’ of your vessel. 11/21/2020 2006 HYPACK® Training Seminar 12

‘True Heave’ The POS/MV has the capability of outputting ‘True Heave’ about 2 -3 minutes after the actual measurement. The POS/MV logs this data to a file. The file with ‘True Heave’ can be read into MBMAX. This only works if the POS/MV and the computer clock are ‘synchronized’ to the same time source (GPS clock). – This is one of the few instances where you need to synch the clock! 11/21/2020 2006 HYPACK® Training Seminar AVI TRUE HEAVE 13

Sound Velocity Corrections 3 Approaches Method Program Calibrating your echosounder with a bar check. None. Correcting with a velocity profile SOUND VELOCITY Correcting for sound velocity based on measured errors at each depth. SOUNDING ADJUSTMENT 11/21/2020 2006 HYPACK® Training Seminar 14

The Bar Check 1 1. Lower a bar or plate 5’ or 2 m beneath the surface. • Adjust the ‘zero’ or ‘draft’ or ‘tide’ knob on your sounder until you read the correct sounding. 2 2. Lower the bar to your intended depth of measurement. • Adjust the sound velocity speed until you read the correct value. 3. Repeat steps 1 and 2 until you don’t have to make any adjustments. • Your echosounder will now output soundings that have sound velocity corrections factored into the output depth. 11/21/2020 2006 HYPACK® Training Seminar 15

Problems with Bar Checks Wave action. (Nothing like trying to calibrate your sounder to a tenth of a foot while standing in a 2’ sea. ) Currents that move the bar from beneath the transducer when you lower it, limiting your ability to see it. Performing the bar check outside your survey area. Surveying with a single bar check in an area where the sound velocity profile changes (fresh versus salt water boundaries). 11/21/2020 2006 HYPACK® Training Seminar 16

Using Info from a Velocity Probe For single beam users: – Use the SOUND VELOCITY program to enter the velocity information. – Load the resulting *. VEL file into the SINGLE BEAM EDITOR. AVI SOUND VELOCITY JPG *. VEL in SBMAX For multibeam users: – Use the SOUND VELOCITY program to enter the velocity information. – Load the resulting *. VEL file into the MULTIBEAM EDITOR. Or – Enter the SOUND VELOCITY information directly into the data files while in HYSWEEP SURVEY. 11/21/2020 2006 HYPACK® Training Seminar AVI *. VEL in HYSWEEP SURVEY 17

SV Corrections from Measured Errors Lower a bar to specific depths beneath the static water line. Note what the echosounder reports. Take the difference (True Depth – Reported Depth) and enter it in the table in SOUNDING ADJUSTMENTS. 11/21/2020 2006 HYPACK® Training Seminar 18

SOUNDING ADJUSTMENTS Process the data in the SINGLE BEAM EDITOR. Enter your Depth and Error information into the SOUNDING ADJUSTMENTS program. Take the resulting edited ‘ALL’ format data files and process them through SOUNDING ADJUSTMENTS. 11/21/2020 2006 HYPACK® Training Seminar AVI SOUNDING ADJUSTMENTS JPG RESULTS IN SBMAX 19

Water Level Corrections (Tides) Method Program Telemetry Tide Gauge SURVEY with telemetry tide driver Manual Entry During SURVEY RTK TIDES SURVEY using KINEMATIC. DLL or GPS. DLL Manual Entry During Post Processing MANUAL TIDES Prediction from High & Low Water Times and Heights MANUAL TIDES Harmonic Predictions HARMONIC TIDES Interpolating Between Stations Tide Adjustments routine in SBMAX Tidal Zoning TIDAL ZONING (New!) 11/21/2020 2006 HYPACK® Training Seminar 20

Water Level Corrections _2 Final Depth = Raw Depth + Tide Correction + Draft Correction + SV Correction + …. This means your tide correction will be a negative value if the water level is above the chart datum. If you are working in elevation: Chart Datum Level - Final Depth Final Elevation Chart Datum Level = 1200 Final Depth = 20 Final Elevation = 1180 11/21/2020 . . _1 Water Level . Tide Correction . . . Chart Datum Measured Depth _0 Chart Sounding The Bottom 2006 HYPACK® Training Seminar 21

Telemetry Tides Uses a device driver – – Tidalite Gentide Valeport Hazen Update rates – Some based on ‘query’ – Some based on equipment Generates ‘TID’ record in RAW data file at every update 11/21/2020 2006 HYPACK® Training Seminar 22

Manual Entry During SURVEY Writes a TID record: – Any time you change the Tide Correction. – At the start of line. Problem: – There is no interpolation between values. 11/21/2020 2006 HYPACK® Training Seminar AVI Manual Entry of Tide 23

RTK Tides Compute the tide based on vertical movements of the GPS antenna RTK TIDES has its own presentation. 11/21/2020 2006 HYPACK® Training Seminar 24

Manual Entry in Post-Processing Enter times and corrections into the MANUAL TIDES program. Generate corrections based on: – Linear – B-Spline – High/Low Water Times and Heights New Version supports multiple day TID files! Enter *. TID file in SBMAX or MBMAX. 11/21/2020 2006 HYPACK® Training Seminar AVI MANUAL TIDES – Linear & Spline AVI MANUAL TIDES – Min/Max 25

Importing Tides from NOAA provides tide observations for most major ports in the USA. Users can download this information to an ASCII TXT file and then import the data into the MANUAL TIDES program. NOAA Link: http: //140. 90. 121. 76/data_retrieve. shtml? input_code=100111111 vwl 11/21/2020 2006 HYPACK® Training Seminar 26

Harmonic Predictions Uses Port Factors and Day Factors from British Admiralty Publication NP 203. Computes a predicted tide, based on harmonic constituents. Saves result to a *. TID file. Do not use French constituents, as they are not ‘combined’. 11/21/2020 2006 HYPACK® Training Seminar AVI HARMONIC TIDES 27

Tide Adjustments Interpolates tide correction based on the distance of sounding between two gauges. Routine is embedded in SINGLE BEAM and MULTIBEAM EDITORS Need: – *. TID file for each gauge (2 or more) – *. LNW for centerline of river – Distance of gauges along centerline 11/21/2020 2006 HYPACK® Training Seminar AVI Tide Adjustment 28

Tidal Zoning Generates tide corrections at the boat location based on magnitude difference and time difference models from primary tide location. TIDAL ZONING has its own presentation. 11/21/2020 2006 HYPACK® Training Seminar 29

Single Beam Editor (SBMAX) Spreadsheet – Order is configurable. – Direct export to ASCII file – Cursor tracks profile and survey cursor. Survey Window – Shows track line versus planned line. – Background charts can be displayed. Profile Window – High and/or low frequency depths – Raw and/or corrected depths – Horizontal scaling: Depth vs. Time Depth vs. Distance – Geometric and GPS quality filtering 11/21/2020 2006 HYPACK® Training Seminar 30