Carlson Merlin LT User manual

Merlin LT user manual H-0218-8000-01-B January 2020
Merlin LT
Vessel-based LIDAR system
user manual

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Contents
1Customer information.............................................................................................................................................................................5
1.1 Dear customer .............................................................................................................................................................................5
1.2 User manual ................................................................................................................................................................................5
1.3 General safety .............................................................................................................................................................................5
2Introduction ............................................................................................................................................................................................7
2.1 System overview..........................................................................................................................................................................7
2.2 Applications .................................................................................................................................................................................7
3Equipment description ...........................................................................................................................................................................8
3.1 Merlin LT......................................................................................................................................................................................8
3.2 Cables .......................................................................................................................................................................................11
3.3 Transit case ...............................................................................................................................................................................13
3.4 USB drive ..................................................................................................................................................................................14
3.5 Merlin diagnostic tool software ...................................................................................................................................................14
3.6 Optional accessories..................................................................................................................................................................15
4Installation ...........................................................................................................................................................................................16
4.1 Choosing a mounting location for the Merlin LT .........................................................................................................................16
4.2 Choosing an appropriate orientation ..........................................................................................................................................19
4.3 Lever arm offset measurement ..................................................................................................................................................20
4.4 Lever arm offset measurement when using the mounting plate..................................................................................................23
4.5 Cable runs .................................................................................................................................................................................29
5Electrical installation ............................................................................................................................................................................30
5.1 Merlin LT Power cable ...............................................................................................................................................................31
6Merlin LT time-tagging .........................................................................................................................................................................32
7Operation of Merlin LT .........................................................................................................................................................................35
7.1 Network set-up...........................................................................................................................................................................35
7.2 Pinging the Merlin LT laser.........................................................................................................................................................36
7.3 Changing the Merlin LT network settings ...................................................................................................................................38
7.4 Setting up Merlin diagnostic tool software to receive external timing ..........................................................................................44
7.5 Checking the laser operation......................................................................................................................................................45
7.6 Checking the timing source........................................................................................................................................................46

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7.7 Other functions of the Merlin diagnostic tool software.................................................................................................................51
7.8 Navigation software ...................................................................................................................................................................51
8Maintenance and care of Merlin LT ......................................................................................................................................................52
8.1 General......................................................................................................................................................................................52
8.2 Preventative maintenance..........................................................................................................................................................52
9Mechanical drawings ...........................................................................................................................................................................53
9.1 Merlin LT positioned at 90° vertical angle...................................................................................................................................53
9.2 Merlin LT positioned at 0°vertical angle......................................................................................................................................54
10 Laser safety .........................................................................................................................................................................................55
10.1 Merlin LT laser module...............................................................................................................................................................55
11 Compass safe distance........................................................................................................................................................................57
12 Merlin LT Specifications .......................................................................................................................................................................58
13 Product information..............................................................................................................................................................................59

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1 Customer information
1.1 Dear customer
The Merlin LT system is designed to be easy to operate. However, we would ask you to take the time to read these
operating instructions carefully before using the system, and to keep the manual with the instrument at all times.
For any feedback or comments, or if there are questions about the Merlin LT which are beyond the scope of this
manual, contact the product support department at Carlson, or your local Carlson representative.
Alternatively, for information on your local Carlson-approved service centre, visit our website: www.carlsonsw.com.
To ensure best service, please make a note of your Merlin LT’s serial number. This can be found on the instrument.
1.2 User manual
This Merlin LT manual has a Carlson part number of H-0218-8000.
This version is H-0218-8000-01-A, released in November 2019.
It is important that you read this manual carefully before using the equipment. The manual comprises three main
sections:
1. The Merlin LT vessel-based lidar system hardware, describing the Merlin LT system and all accessories
supplied with a standard system.
2. The installation and use of the Merlin LT system on a vessel. Be sure to fully understand this section before
starting an installation.
3. The Merlin diagnostic software, showing how the software enables basic configuration and testing of the
Merlin LT.
This manual does not cover the calibration of the Merlin LT in hydrographic acquisition software packages. These
are detailed in separate quick-start guides: QINSy (Carlson part no. H-9931-9506), HYPACK (H-9931-9505), and
PDS (H-9931-9512).
This manual has been compiled with care. However, should you discover any errors we would be grateful if you
could contact Carlson directly. Reproduction in whole or in part, including utilisation in machines capable of
reproduction or retrieval, without the express written permission of Carlson, is prohibited. Reverse engineering is
also prohibited.
The information in this document is subject to change without notice. Carlson has made considerable efforts to
ensure the content of this document is correct at the date of publication but makes no warranties or representations
regarding the content. Carlson excludes liability, however arising, for any inaccuracies in this document.
1.3 General safety
CAUTION: Before unpacking and installing the Merlin LT system, read the safety instructions throughout this manual
carefully and ensure that they are followed at all times by all operators. Failure to do so could adversely affect the
performance of the Merlin LT system and/or lead to personal injury. Operators must be trained in the use and
application of the Merlin LT system and accompanying accessories before being allowed to operate the system.
1.3.1 Operation and maintenance
Following the simple maintenance procedures below will prolong the operational life and continued high

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performance of the system. The user should determine the frequency of inspection and maintenance actions
according to the conditions of use.
•The product is to be used only with the appropriate Carlson-supplied cabling.
•Installation of the Merlin LT system must be performed only by trained personnel.
•Changing the Merlin LT port and IP addresses must be carried out using only the Merlin diagnostic tool
software by appropriately trained personnel.
•Disconnect power before performing any maintenance operations.
•Maintenance is restricted to procedures described in section 8.
•Beware of unexpected mechanical movement. The user must remain outside the full working envelope of
the Merlin LT system whilst in operation.
•It is the machine supplier’s responsibility to ensure that the user is made aware of any hazards involved in
operation, including those mentioned in Carlson product documentation.
•The Merlin LT system must be transported in Carlson-supplied packaging.
•This equipment is not suitable for use in a potentially explosive atmosphere.
1.3.2 Precautions
•There are no user-serviceable parts inside the unit. Do not remove any panel. Do not attempt to
service parts inside the unit. If servicing is required please contact Carlson.
•Unauthorised removal of any panel may expose live connection points and non eye-safe laser
radiation.
•Avoid directing the laser apertures towards the sun or other high-powered, infrared light sources.
•Avoid mechanical shocks
•The laser is driven by a rotating motor. If the motor is rotated by hand or prevented from moving by an
obstruction, the motor will not be damaged. It is advisable, however, to minimise any manual movement of
the laser and to keep the instrument away from potential obstructions so the motor may turn freely.
•Users should not manually or otherwise obstruct the operation of the motor or allow clothing to come into
contact with the device, to avoid entrapment in the unit.

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2 Introduction
2.1 System overview
Merlin LT is a development from the Merlin, Carlson’s first, time-tagged, vessel-based lidar system. The Merlin LT
can be operated from any vessel platform and is designed specifically for use in extreme and changeable marine
environments. Its plug-and-play design offers quick and simple deployment, as well as easy integration into existing
vessel infrastructure, such as an inertial measurement unit (IMU), global navigation satellite system (GNSS)
receivers, and industry-standard hydrographic acquisition software packages.
The Merlin LT is designed to be lighter-weight, and of a smaller footprint, than the standard Merlin system, while
the capabilities of the laser remain the same.
The instrument employs the ‘time-of-flight’ laser measurement technique to measure ranges to above-water
topography without the need to place reflectors at the target. This allows accurate measurements to be made of
inaccessible points, such as cliff faces and rock groynes, from the relative safety of the survey vessel. With the
Merlin LT integrated into the vessel’s navigation system and the sensors all calibrated with respect to the IMU, the
laser data can be collected at the same time as underwater data is collected.
Merlin LT is supported by drivers in all the main hydrographic survey / navigation software packages, including
QINSy, HYPACK, EIVA and PDS. This support provides flexibility to end users involved with a wide variety of clients,
applications and global locations.
Merlin LT observes 36,000 points per second, with a 360° field of view.
The Merlin diagnostic tool software is supplied with Merlin LT. This can be used to program IP addresses, change
port numbers, fault-find, and carry out diagnostic checks on the system.
2.2 Applications
This innovative instrument is suitable for a large number of surveying and measuring functions, including:
•Infrastructure planning
•Offshore construction
•Coastal erosion monitoring
•Port and harbour surveys
•Navigation chart updates
•Flood-risk management
•Canals and inland waterways
•Inspection surveys
•Bridge condition surveys
•Terrestrial mobile mapping

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3 Equipment description
The sections below describe each individual hardware element of a standard Merlin LT vessel-based lidar system.
3.1 Merlin LT
The Merlin LT unit incorporates a rotating laser range finder which is housed with a motor and encoder in a weather-
proof pod, held between two ‘A-frame’ pillars that sit on a base plate.
3.1.1 Laser
The laser contains the optical and electronic components that allow distance measurements to be recorded to
reflectorless targets up to 250 m from the instrument.
The laser uses a ‘time-of-flight’ method to measure ranges to remote targets.
The two lenses visible within the laser module are the transmitting and receiving optics. It is through these optics
that the infrared measuring laser is fired, and its reflected light is received back into the instrument.
The laser measures 36,000 ranges each second, to an accuracy of +/-1 cm.
The laser ranges up to a limit of 250 m to 90% reflective material (e.g., Kodak white card). However, the maximum
achievable range at any given time or location will depend on a number of factors. In some circumstances these
may prevent any readings from being taken:
•dark, light-absorbent surfaces such as coal;
•atmospheric conditions such as dust, fog, heavy rain and snow;
•wet, slick, shiny or very smooth surfaces;
•an acute angle between the laser and the surface.
The minimum, calibrated range of the laser is 0.5 m. At shorter distances, readings may still be recorded, but their
accuracy may be diminished.
An internal motor physically rotates the laser housing at up to 20 times per second.
An encoder measures the rotational angle of the laser to an accuracy of 0.01°.
Figure 1 Rotating laser module

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3.1.2 A-frame and base plate
The pod can rotate vertically around the vertical pivot at the top of the A-Frame. The fixed angles are 90° (horizontal),
45° and 0° (vertically up).
Changing the vertical inclination of the Merlin can help to produce more useful data, depending on the nature of the
scene being scanned and on the specific project requirements.
Leave the pod horizontal – at 90° – to generate vertical sections of points as the laser rotates.
Incline the laser to 45°, and the section of scanned points is also inclined. This can help to pick out vertical features
such as lamp posts, pillars and building edges.
A-frame
Base plate
Vertical
locking stud
Measurement
datum point
Figure 2 Merlin positioned vertically at 90°, 45° and 0°
Figure 3 Merlin A-frame and base plate

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At 0° The Merlin LT generates horizontal sections of points. This orientation can be used for proximity detection and
to assist dynamic positioning.
If the unit is repositioned with a different vertical angle, new lever arm values must be used. The pitch calibration
values must also be changed in your navigation package.
Use the four holes in the base plate to secure the Merlin LT directly to a mounting point on a vessel. Alternatively,
use the base plate to secure the Merlin LT to the mounting plate (see section 3.6.1).
A central point on the base plate marks a measurement datum point which you can use when surveying the lever
arm offset.
3.1.3 Connectors
There are four connectors on the Merlin LT unit, at the rear of the pod.
Each connector is uniquely matched to one of the supplied cables described in section 3.2.
When the cables are correctly and securely attached to the Merlin LT, the connections are watertight.
The connectors are supplied with protective caps which should be placed on the connector when the system is not
in use and cable are disconnected.
Power
Serial ZDA input
Ethernet
PPS input
Figure 4 Merlin LT connectors