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 channelsP1 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