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Kongsberg Simrad Multibeam Echo Sounders

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Presentation on theme: "Kongsberg Simrad Multibeam Echo Sounders"— Presentation transcript:

1 Kongsberg Simrad Multibeam Echo Sounders
The Evolution of the Kongsberg Simrad Multibeam Echo Sounders by Dr. Freddy Pøhner © KONGSBERG April 25, 2017

2 KONGSBERG main business areas
25. april 2017 Maritime Defence & Aerospace © KONGSBERG April 25, 2017

3 Satellite Positioning &
Kongsberg Maritime Business Support Torfinn Kildal President Steinar Aabelvik CFO Human Resources/Administration: Finn H Kristensen Quality Management: Finn H Kristensen IS/IT systems: Steinar Aabelvik Communication: Gunvor H Midtbø Divisions Marine Electronics Jan E Berner Sales & Marketing Tor Erik Sørensen Dynamic Positioning & Navigation Ole Gunnar Hvamb Marine Automation Lars Gørvell-Dahll Process Automation Nils E Standal Hydroacoustics Rolf Arne Klepaker Satellite Positioning & AIS Bjørn Fossum Marine IT Bjørn T Frøshaug © KONGSBERG April 25, 2017

4 We participate where the action is
25. april 2017 Global presence HEAD OFFICE OFFICES © KONGSBERG April 25, 2017

5 Kongsberg Maritime premises in Horten, Norway
© KONGSBERG April 25, 2017

6 M/K Echo, a 30 m vessel for test and demonstrations
© KONGSBERG April 25, 2017

7 “Pingeline”, a 32 feet hydrographic launch, for testing
© KONGSBERG April 25, 2017

8 Kongsberg transducer test tank with EM 1002 transducer being tested
© KONGSBERG April 25, 2017

9 Testing of a Multibeam Echo Sounder System
© KONGSBERG April 25, 2017

10 In-door test tank: 10 x 6 x 6 meters
© KONGSBERG April 25, 2017

11 Hydrographic Applications
Mapping of Rivers and Canals Marine Geology Scientific research Habitat mapping Exclusive Economic Zones mapping (EEZ) Detailed Mapping (ROV, AUV applications Multibeam Echo Sounders Nautical charting Single Beam Echo Sounders Operation Support: Cable Laying Sub Bottom Profiler Marine Data Management Processing software Route Surveying Operation Support: Dredging Port and Harbour Surveying Mapping of Rivers and Canals © KONGSBERG April 25, 2017

12 Launching sequence of multibeam models
EM 100 EM 3000 EM 300 EM 1000+EM 12 EM 121 EM 120+EM2000 SBP 120 EM 3002 EM 710 time © KONGSBERG April 25, 2017

13 The Quality of a sounding process(1):
Seabed mapping process Sounding process (on ship) Data processing Echosounder Positioning Motion compensation Sound vel modeling Seabed Terrain Terrain model = ? = Plotter Workstation Colour Postscript Printer How well does the terrain model represent the seabed terrain? © KONGSBERG April 25, 2017

14 The Quality of a sounding process(2):
The terrain model is a mathematical surface based upon a set of depth soundings The best terrain model is obtained by: A. Precise depth soundings B. Smallest possible acoustic footprint for each sounding C. Precise positioning of each sounding D. High density of soundings E. Even spacing between soundings These principles have been and still are the guidelines for most of our developments © KONGSBERG April 25, 2017

15 Acoustic principles developments
1986/EM 100: Basic properties of the Simrad multibeams: Phase + amplitude bottom detector Automatic gain steering and bottom tracking Split beam phase Full beam amplitude Phase Detect © KONGSBERG April 25, 2017

16 Refraction of Acoustic Beams
Snell’s law of refraction: sin(Ai)/Ci=constant All models have had built-in real time compensation. Early models used lookuptable + interpolation, accurate realtime calculation since 1997. © KONGSBERG April 25, 2017

17 Moving vessel profilers: Frequent sampling of sound velocity profiles
Multibeams interface MVP’s, no interruption of sounding when a new profile is entered (due to realtime calculation of refraction) © KONGSBERG April 25, 2017

18 The Mills Cross array was introduced with EM 12 in 1990
Forward direction on ship Transducer array configuration Transmit beam Receive beam Effective beam footprint Transmit Receive © KONGSBERG April 25, 2017

19 Transmission process: FRDT principle
This was introduced with EM 12 in 1990. Advantages: Higher source level (=increased range) +reduced problems with sidelobes from the specular return. Transmit in sectors, and use different frequencies Requires a larger transducer + direct steering of all transducer elements in 2 dimensions © KONGSBERG April 25, 2017

20 Equi-distant beamspacing
Equiangle Equidistant In-between Equi- distant beam spacing was introduced as an improvement to the EM 12 + EM 1000 in the early 1990’s © KONGSBERG April 25, 2017

21 Equidistant beamspacing
Example at 10m depth crosstrack beam spacing 0.00 0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 Angle 5.00 15.00 25.00 35.00 45.00 55.00 65.00 beam angle crosstrack distance beam spacing EM 3002 beam spacing Reson 8125 Improved sounding density in the outer part of the swath © KONGSBERG April 25, 2017

22 Adapting the system to varying depths and bottom conditions
Manual Mode Sector fixed to operator set angles Auto Mode Sector limited by: Max angle set by operator Max coverage (deg) set by operator Signal to Noise Ratio Introduced early 1990’s Sector Coverage © KONGSBERG April 25, 2017

23 Beamformed seabed imagery (Snippets)
2 different Data Sets are derived: A. Beam Intensity=Mean Backscatter Strength over the Footprint B. Sonar Image Data= All the individual Backscatter values Beam Acoustic Footprint of Beam Range Resolution cell This was introduced in 1990 for EM 12 and EM 1000 © KONGSBERG April 25, 2017

24 Bathymetry and Sonar Image combined in 3D
EM 12D - Surveyed by IFREMER Ifremer pioneered the development of software to process Seabed imagery © KONGSBERG April 25, 2017

25 EM 300 (30 kHz) Multibeam Bathymetry & Backscatter
Bathymetry & Imagery EM 300 (30 kHz) Multibeam Bathymetry & Backscatter Data courtesy of C & C Technologies Inc. © KONGSBERG April 25, 2017

26 1995/96: EM 3000 was introduced Single Dual This step was made possible by availability of more compact electronics. A sonar head has a mills cross transducer array + 2 electronic boards: 1 for transmission and 1 for reception. CHS was the first client. © KONGSBERG April 25, 2017

27 Calculation of Depth Data
Transducer mounting pos + angles Surface sound vel. Sound vel. profile T=2way travel time Sounding depth (z) Rel. pos. of sounding (x,y) Co-ordinate transformations and modelling of transmission through water Ar=Beam angle rel. transducer Heave Roll Pitch Exact algorithm was introduced for EM 3000 in 1995, allowed for free mounting angles of sonar heads © KONGSBERG April 25, 2017

28 Test arrangement for they German Waterways Authority
© KONGSBERG April 25, 2017

29 Accuracy as function of swath width
© KONGSBERG April 25, 2017

30 Test Result from a Lock Survey Result Construction Drawing
© KONGSBERG April 25, 2017

31 A multielement transmit array is required,
Pitch Stabilisation Introduced from 1990 Stabilization for pitching is obtained by steering the transmit beam electronically forward or aft at the time of transmission, based upon input from the motion sensor. A multielement transmit array is required, + several steerable transmitters © KONGSBERG April 25, 2017

32 The effect of pitch stabilisation
Sounding patterns on the bottom Competitor result, Without pitch stabilisation EM 3002 result © KONGSBERG April 25, 2017

33 Roll Stabilization Since 1986
Each Receive Beam is stabilized for roll by the Beamformer, using input in real time from the Motion Sensor. All beam pointing angles are thus constant, related to the vertical axis. The roll angles will be different for the different beams © KONGSBERG April 25, 2017

34 The effect of roll stabilised beams
Unstabilized swath Effective Swath Unstabilized: The swath is rolling sideways, and the effective swath is then reduced. Stabilized: The swath is not influenced by roll movements © KONGSBERG April 25, 2017

35 Compensating for vessel yaw movements
No compensation 2000m Calculation of sounding pattern on bottom Ship speed: 10 knots Depth: m Pitch: +/-5 degrees, 15sec period Yaw: +/-6 degrees, 200sec period 1000m -1000m Pitch compensation only Fulll compensation for pitch and yaw 2000m 1000m -1000m 1000m 2000m -1000m (As EM 120) © KONGSBERG April 25, 2017

36 EM 120 and EM 300 Multibeam echo sounders
Without Yaw stabilisation From 1997 With Yaw stabilisation Calculated by UNB, Canada © KONGSBERG April 25, 2017

37 There is extra cost to produce yaw stabilized TX beams
TX Beam forming The transmit transducer is made of many single elements. On some multibeams a number of single elements are connected to make one stave. This allows for pitch compensation (One cable pair per stave) Other multibeams has individual control of all the single elements in the array. This may be used to form several transmit beams and to compensate for roll, pitch and yaw. (One cable pair per element) There is extra cost to produce yaw stabilized TX beams © KONGSBERG April 25, 2017

38 System accuracy improves over time
© KONGSBERG April 25, 2017

39 TRB 32 Transmit/Receive Board for 32 channels
P1 P2 Kongsberg develops its own ASIC’s and HYBRID circuits for the sonar front-end boards © KONGSBERG April 25, 2017

40 64 channel transmitter board
Plugs for connection to transducer elements Backplane P1 Backplane P2 Transmitter hybrid circuits Each transmitter is a special purpose HYBRID circuit © KONGSBERG April 25, 2017

41 EM 1002 Optional Retractable Hull Unit
The hull unit provides: Transducer protection during transit Good acoustic conditions when extended Active pitch compensation of beams It is mounted on a cylindrical trunk which is welded to the ship’s hull Max survey speed with Hull Unit is 10 knots © KONGSBERG April 25, 2017

42 “Kilo Moana” - EM 1002 transducer being fitted
© KONGSBERG April 25, 2017

43 Transducer Gondola 25. april 2017 © KONGSBERG April 25, 2017 1

44 Titanium plates for light protection against ice was introduced
Ice breaker solutions Titanium plates for light protection against ice was introduced in 1990. Ice breaker solutions have been developed since, for 12 and 30kHz © KONGSBERG April 25, 2017

45 EM 3000D Bow Installation 25. april 2017 © KONGSBERG April 25, 2017 1

46 The acoustic near-field – Beam focussing
Without focussing: Inside the near field the beam is as wide as the physical size of the transducer Near Field L Beam- width © KONGSBERG April 25, 2017

47 Beam focusing Introduced from 2004 Focal point
width L Near Field Dynamic focusing: The focus point is shifted as function of time/range Introduced from 2004 © KONGSBERG April 25, 2017

48 Beam focusing of transmit beams
25. april 2017 Focusing in the nearfield on transmit is feasible by using three separate transmit sectors per ping From 2005 Focus range left sector Focus range central sector Focus range right sector Footprint alongtrack © KONGSBERG April 25, 2017

49 The Human Interface (MERLIN - Unix)
Monitoring Control Depth Profile Geographic window Beam Intensity/ Quality Waterfall By choosing AUTO for parameters, the system will adapt to changing depth © KONGSBERG April 25, 2017

50 Operators Display (SIS- Windows or Linux)
Gridded terrain model: 2D or 3D Signal strength Depth profile Raw hydrophone data 3D (waterfall) 2004-- Watercolumn (beamformed) Seabed Imagery © KONGSBERG April 25, 2017

51 Only stave data is recorded
Raw data recorder The raw data recorder is mounted on the side of the transceiver cabinet. Introduced approx. 1999 Only stave data is recorded © KONGSBERG April 25, 2017

52 Processed result from raw data recorder
Water column display processed from 1 ping with EM 300 Courtesy of Xavier Lurton, Ifremer © KONGSBERG April 25, 2017

53 Beamformed raw data can now be recorded and post processed
EM 3002 Real time Water Column display Beamformed raw data can now be recorded and post processed © KONGSBERG April 25, 2017

54 Some recent improvements
Broad band transducers – composite ceramics Use of FM sweep/chirp as transmit waveforms High resolution beam processing Multiple sounding profiles per ping © KONGSBERG April 25, 2017

55 Composite ceramics for wide bandwidth
25. april 2017 EM 710 Transmit Transducer 30-50% bandwidth can be obtained © KONGSBERG April 25, 2017

56 FM sweep/chirp transmit pulses
The use of FM sweep or chirp signals is being implemented on EM 710 as the first system It requires new beamforming algorithms, pulse compression, and increased capacity for transmitting long pulses. This is used to increase the energy content of the TX pulse. A longer range can be obtained without sacrifice of resolution © KONGSBERG April 25, 2017

57 High resolution beam processing
In EM 3002 the number of soundings (254 per sonar head) is higher than the number of acoustic beams (160 per sonar head) This is a technique to increase and improve the system resolution. ”Soft” beams in between the acoustic beams are generated to produce the extra soundings. A special signal processing technique, high resolution beam processing, is used in order to reduce the acoustic footprint of each sounding, and produce soundings that are independent. The best horisontal system resolution is then approximately 20cm. © KONGSBERG April 25, 2017

58 The full number of beams is maintained also when the swath is reduced.
Full swathwidth Reduced swathwidth 254 soundings 254 soundings This is a unique feature. If the swath width is reduced – on purpose or due to maxrange – the full number of soundings is still produced inside the active swath. Result: A more dense pattern of soundings+ reduced footprint size of each sounding. © KONGSBERG April 25, 2017

59 Result example, 18m depth 120 degree swath
Data processing by QPS © KONGSBERG April 25, 2017

60 Result example, 18m depth 90 degree swath
The details are sharper! Data processing by QPS © KONGSBERG April 25, 2017

61 Evolution of resolution
EM : 1.8 x 3.5 deg EM : 1 x 1 deg EM : 1.5 x 1.5 deg EM 300/ : 1 x 1 deg EM : 0.5 x 1 deg The no. of soundings/ping and the ping rate is increasing due to more computer power being available. EM 3002D and EM 710 will both be able to produce close to soundings per second. © KONGSBERG April 25, 2017

62 SBP 120 Multibeam Sub Bottom Profiler
25. april 2017 SBP 120 Multibeam Sub Bottom Profiler Receive beam width Transmit beamwidth EM 120 12 kHz SBP 120 2.5-7kHz Common receive aray Transmit beam Receive beam Effective beam footprint © KONGSBERG

63 Floating point receiver A/D
SBP 120 block diagram 25. april 2017 Frequency 2.5 – 7 kHz Pulse forms: Chirp CW Ricker Floating point receiver A/D Arrays lengths: 8m degree beams 4m degree beams 2m – 12 degree beams © KONGSBERG April 25, 2017

64 SBP120 - 3° Specular return / backscatter
25. april 2017 Smooth surface layer Rough buried structure Illustrasjon av hvordan “sediment roughness” gjenspeiles i mottakervifta. Øverst et pent sedimentlag, nederst et veldig grovt lag – stein? Også tydelig langsskips naturligvis. Echogram Multiple beams © KONGSBERG April 25, 2017

65 SBP 120-3°: Sloping terrain
25. april 2017 SBP 120-3°: Sloping terrain Image ~4.5km alongtrack, ~450 ms ~ 335 m from top to bottom -> average slope along ~ - 4° Horisontalaksen utgjør ca 4.2 km Vertikal grid 25 ms, Penetrasjon ca 100 ms = 75 meter. Data © SHOM © KONGSBERG April 25, 2017

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