Abbreviation Terminology

A/AMP Amperes LONG Longitude
ABS American Bureau of Shipping (Class Society) LSZH Low Smoke Zero Halogen
ACP Azimuth Change Pulse m Metre
ADCP Acoustic Doppler Current Profiler m/s Metre per second
ADF Automatic Direction Finder MAC Machinery Alarm & Controls
AIS Automatic Identification System MARPOL Marine Pollution Prevention
AFC Automatic Frequency Control MB Megabyte
AHT Anchor Handling Tug MHz Megahertz
AHTS Anchor Handling Tug Supply Vessel MoComp Motion Compensation
ALRM Alarm M/V or MV Motor Vessel
AMSA Australian Maritime Safety Authority MOB Man Overboard
ARP Azimuth Reset Pulse NM Nautical Mile(s), also seen as Mnmi
ARPA Automated Radar Plotting Aid NMEA National Marine Electronics Association
ATON Aid to Navigation NOFO Norwegian Clean Seas Association for Operating Companies
BIST Built-in System Test ns Nanosecond
BV Bureau Veritas (classification society) Θs Peak Wave Direction
CBT Computer-based training Θu Surface Current Direction
CFAR Constant False Alarm Rate OSD/OIL Oil Spill Detection
COG Course Over Ground OSRO Oil Spill Response Organization
CPA Closest Point of Approach OSRV Oil Spill Recovery Vessel
CRS Course OSV Offshore Supply Vessel
CTV Crew Transfer Vessel OWF Offshore Wind Farm
° Degree OWS OceanWaveS GmbH
Dec Decimal Degrees Pd Probability of Detection
DGPS Differential Global Positioning System PERFMON Performance Monitor
DM Degrees, Minutes PFa Probability of False Alarm
DMS Degrees, Minutes, Seconds PIW Person in Water
DNV Det Norkse Veritas PLEN Pulse Length
DP Dynamic Positioning PPS Pulse per Second
DR Dead Reckoning PRF Pulse Repetition Frequency
DWFA Directional Wave Finding Algorithm R&D Research and Development
E&P Exploration and Production Racon Radar Transponder Beacon
EBL Electronic Bearing Line RADAR Radio Direction and Range
ECDIS Electronic Chart Display and Information System RCS Radar Cross-Section
EMER Emergency RCU Radar Configuration Utility
ENC Electronic Navigation Chart Rge/Brg Range/Bearing
EO Electro-Optical RIB Rigid Inflatable Boat
ESRI Environmental Systems Research Institute RMRS Russian Maritime Register of Shipping
FAT Factory Acceptance Test RoHS Restrictions of Hazardous Substances
FFT Fast Fourier Transformation RPT Repetition (used for the radar repetition frequency)
ft feet RSi Radar Signal Interface
FPSO Floating Production, Storage, and Offloading RX Receive
FRB Fast Rescue Boat SAR Synthetic Aperture Radar
FRC Fast Rescue Craft SAR Search And Rescue
FRV Fast Response Vessel  
GALILEO Global Positioning System (Europe) SART Search And Rescue Transponder
GB Gigabyte SAT Ship/Site Acceptance test
GIS Geographic Information System sec Second
GL Germanischer Lloyd (German Class Society) SF SeaFusion
GLONASS Global Navigation Satellite System SNR Signal to Noise Ratio
GMDSS Global Maritime Distress and Safety System SOG Speed Over Ground
GMT Greenwich Mean Time SOLAS Safety of Life at Sea
GPS Global Positioning System SPD Speed
GUI Graphical User Interface SSE Sea Surface Elevation
HDR High Definition Radar ST Server Time
HELO Helicopter STAT Status
HH Horizontally Polarized Radar Antenna STBL Stabilized
HMAX Maximum Wave Height STBYTX Standby Transmit
HPOL Horizontally Polarized STC Sensitivity Time Control
HRC High Resolution Current STS Small Target Security/Surveillance
HSC High Speed Craft STW Speed Through the Water
HSE Health, Safety and Environment Tp Peak Wave Period
Hs Significant Wave Height TB Terabyte
Hz Hertz TRIG Trigger
IALA International Association of Lighthouse Authorities TTM Target Tracking Message
IBS Integrated Bridge System TX Transmit
IEC-60945 Certification for Marine Computers and Bridge Electronic Systems TXRX Transmit/Receive
IEEE Institute of Electrical and Electronics Engineers U(u) Surface Current Speed
IN/ICE Ice Navigator™ UTC Coordinated Universal Time
INS Integrated Navigation System V Volts
IMO International Maritime Organization VPOL Vertically Polarized
IR Infra-Red VRM Variable Range Marker
ISPS International Ship and Port Facility Security VTIS Vessel Traffic Information System
IT Information Technology VTMIS Vessel Traffic Management and Information System
JIP Joint Industry Project VTMS Vessel Traffic Management System
KHz Kilohertz VTS Vessel Traffic System/Service
Kph Kilometers per Hour (km/h) VV Vertically Polarized Radar Antenna
KW Kilowatt WAAS Wide Area Augmentation System
λp Peak Wave Length WaMoS® Wave and Surface Current Monitoring System
LAN Local Area Network WAN Wide Area Network
LAT Latitude XPOL Dual/Cross Polarized

​​Video Demos

sigma S6 OSD Oil-on-Water Test

This video shows the result of an oil-on-water exercise where two separate oil releases were made and detected by the sigma S6 OSD system, which then alerted the operator. The two spills were then acknowledged by the operator, the system automatically outlined them and began tracking their movement.

Scuba Ice Trial

Rutter Inc. participated in an ice trial with the U.S. Coast Guard in the Great Lakes wherein a vessel released a scuba diver into the water. This video shows the diver emerging from below the ice and swimming towards the vessel.

Ice Flow by Port Vladivostok

This video shows February ice flowing by the VTS Center of Port Vladivostok in Russia, with the imaging made up of 5-minute screen shots of the sigma S6 system. Screen shots courtesy of the Cord Group – a dealer in the Rutter Inc. sales network


Frequently Asked Questions

FAQ - sigma s6 Systems

A: The system has been shown to be capable of detecting a light (0.00004 mm) to silver (0.00007 mm) sheen.
A: Any oil that suppresses capillary wave action.
A: We do not provide cameras. We can connect to the FLIR Voyager II and M series of cameras. We would suggest calling your local FLIR dealer for pricing on these two cameras.
To find a local dealer, go to
Rutter’s sigma S6 radar systems can send commands via Serial data connection to the camera to slew it to a selected radar target. A future sigma S6 software release (estimated 2014) will provide integration of full control and video window in the sigma S6 radar display.
FLIR Voyager II
FLIR M series
A: Radar cannot measure thickness of oil layers, but our new OSD version shows different gradations of grey for different concentration of oil, which typically develop by dispersion and wind drift into separated strains of oil.

Sigma S6 automatically detects and outlines the areas of oil spills. By experience, knowing the type of oil (viscosity), by the color of the oil sheen, the operator may estimate the thickness of the oil slick and assign up to 8 estimated thickness values for different gradations of grey from the radar screen.

The system would then automatically calculate the total estimated volume of oil within the outline polygon.
A: The sigma S6 Oil Spill Detection radar system detects very small depressions in the signal return due to surface oil depressing capillary wave1 action. Once a slick anomaly has been detected, the sigma S6 generates an auto alarm for user oil spill management. Auto outlining of the slick area is generated and maintained in real-time providing slick area, bearing and speed of movement, volume estimation and optional ocean current measurement for slick movement prediction. Sharing of oil slick information is available with third party systems (e.g. Oil Spill Management GIS systems) via the sigma S6 Interface Software Kit. Integration and control of third party infrared cameras (e.g. FLIR cameras) is also available.

Capillary wave, small, free, surface-water wave with such a short wavelength that it’s restoring force is the water’s surface tension, which causes the wave to have a rounded crest and a V-shaped trough. The maximum wavelength of a capillary wave is 1.73 centimeters (0.68 inch); longer waves are controlled by gravity and are appropriately termed gravity waves. Unlike the velocity of gravity waves, the velocity of capillary waves increases with decreasing wavelength, the minimum velocity being 23.1 centimeters per second (9.09 inches per second), where the wavelength is the maximum 1.73 cm. [Encyclopedia Britannica, 2013,]
A: Additional capabilities that be obtained are:
·       Small Target Detection for security and surveillance of national critical infrastructure
·       Wave Height & Ocean Current measurements (wave spectra, based upon WaMoS system integration)
A: The physical theory behind any x-band radar-based oil spill detection limits detection to water with capillary wave action. Without capillary waves (see response to 6 for definition) causing the oil slick to dampen, oil spill detection with X-band radar is not possible. This is accepted and proven as the limits of the technology. Therefore, in highly calm or smooth water, any X-band oil spill detection radar would not provide satisfactory results compared to water where capillary waves are present. This is not a limitation of the system software or radar hardware, it is a consequence of the physical environment.
A: There are none known. Operators and users of the sigma S6 Oil Spill Detection system are typically under non-disclosure agreements as part of their contracts. Therefore Rutter would generally not be in a position to be made aware of situations where the prosecution referenced usage of the sigma S6 Oil Spill Detection system.
A: a) The European Maritime Safety Agency (EMSA), Italy, Castalia, Pollution Control Vessel
b) Shanghai Tech Marine Co. (China Government [co-owner]), Pollution Control Vessel
c) Kiyi Emniyeti (Turkey Government [co-owner]), Pollution Control Vessel
A: Several NOFO Oil in Water Exercises (2008, 2010)
MSRC (USA) oil recovery (2011, 2012)
Shell (Brazil) oil spill incident (2012)
Oil in Ice incident detection and recovery (Norway 2011, Godafoss carrier)
USCG Oil in Ice Exercise (Hollyhock 2013)
A: Minimum detection volume is 5L from oil in water test.
Maximum detection volume is unknown, but a measured 1000L was noted volume during NOFO oil in water exercise.
A: It is common that the sigma S6 Oil Spill Detection radar system would be used in conjunction with available aerial surveillance support. It is NOT a requirement that aerial support be used.
A: As discussed above, all X-band radar based oil spill detection capability is limited by the presence (or lack thereof) of waves for the oil spill to dampen. This is not a Rutter-specific limitation. Rutter does provide a vertically polarized radar antenna option that improves oil spill detection capability over standard horizontally polarized radar antennas. Vertically polarized antennas are used where it is desired to accentuate wind and sea clutter, which is the case with X-band radar based oil spill detection technology. Accentuated wind and sea clutter increases the Rutter systems oil spill detection range, and increases detection capability in lower sea states.
A: Presence of wind driven sea clutter to produce capillary waves (see response to 6 for definition of capillary waves).
No known or observed limitations of currents or their interactions on oil spill dispersion.
Recommended to use a minimum 8ft VPOL antenna (HPOL can also be used, but VPOL gives improved detection capability).
Radar to operate on Short Pulse settings, with highest PRF.
A: Minimum 92m (based on 4.6 m range resolution, therefore radar dependent).
A: Wave action, except where such action is so high that it causes wave breaking activity, will not impact the sigma S6 system’s ability to measure radar returns change due to oil thickness.
A: There is no problem with larger antennas. Generally the larger an antenna, the better the horizontal beamwidth and sampling parameters. Rutter recommends a minimum 8 ft. antenna, preferably VPOL, to enhance sea clutter.
A: Rutter uses scan integration to remove large waves from the processed image to reveal oil spills.
A: Rutter can arrange a visit to an existing client’s installation if requested.  Alternatively, previously recorded data could be used for playback to demonstrate system operability.
A: The dominant factors in the system’s range is defined by the surface sea clutter and the range of the Short Pulse length. For a given sea state, increasing the height of the antenna does improve clutter return, but in general an antenna height of 10 metres or more is sufficient to give proper performance of the system.
A: Like any radar system, X-Band oil spill detection is limited by heavy rainfall, which acts to destroy the physical conditions that allow oil spill detection via radar.
There are no problems with wind. Rutter has successfully detected 15L of oil in 45kt winds during an acceptance test in Spain.
A: As per NOFO policy, manufacturers of OSD systems are not allowed to advertise that their OSD system is “NOFO Certified.”
We can, however, confirm that our OSD system has been found operationally satisfactory for NOFO mode of operation.
A: It is unlikely the water surface of a creek or similarly congested areas could be experience wind effects enough for generating capillary waves. Therefore we would not expect that oil on water could be detected by radar here.
A: IR cameras can detect temperature differences in water. Oil absorbs more sunlight than water, causing surface temperatures to be hotter over an oil slick than over water where there is no oil.
A: The OSD-500 system is able to detect irregularities on the sea surface. The system will give an alarm if irregularities behave like oil spills. These alarms have to be acknowledged if the operator confirms the oil spill visually. False alarms can be negative acknowledged. In case it is an oil spill and the operator ACK the alarm, it will be treated as oil, the area will automatically be outlined, a centroid with an arrow of movement will be placed and it will proceed to track the oil spill.
The OSD-500 system is able to display OSD information on the screen, which includes oil detection, oil trace, time, location, area and drift as well as wind direction.
A: On board vessels or platforms or at coastal sites.
A: For inclusion when one radar cannot be mounted high enough or there are obstructions not allowing the end user a full 360° view we developed a functionality called SeaFusion.
SeaFusion will allow the combination of 2, 3 or 4 radars to achieve the full 360 degree view.  It will present the full 360° view to the end user.  The radars must be supplied by same manufacturer, i.e. JRC+JRC+JRC, Furuno+Furuno, it cannot be JRC+Furuno.
A: To accurately detect the oil spill on the water the X-band radar must be operated in short pulse mode.
A: The minimum operational temperature of our equipment (radar transceiver and antenna) is -40°C.
A: If the current radar on the vessel is suitable, then we will simple slave off of that (which will not affect any signals to your existing radar).  Your existing radar would still be used for navigation. 
A: Only X-band radars are suitable for small target detection.
However, large targets can be detected in precipitation with the S-Band radar.
A: With an 8 ft. antenna with 40 RPM and an X-band transceiver of 25 kW and 3.000 Hz pulse repetition frequency for short pulses, sigma S6 provides a typical maximum detection range of 4 -6 NM for slow and  6 - 8 NM for fast moving targets of RIB size. (Tracking range may be less, depending on the target aspect and wave height. Swimmer in the water tests have shown a detection range of > 1NM under severe clutter conditions.)
A: These are mainly the following parameters:
-    High-resolution signal and image processing
-    Advanced suppression of noise and clutter
-    Motion compensation by using multiple scan averaging
-    Additional user options for signal filtering or linearity of amplification or image processing
Also: All these go into the target detection formula as “Processing Gain.”
A: Ice edges can only be detected and displayed with high-resolution signal and image processing as it is offered by the sigma S6 system. 
A: Only an Ice Radar can show icebergs of the smallest categories, so-called “growlers”, which typically have a height above water of only 0.5 to 1 metre.
A: The radar is the only means for looking into your local environment most of the time. In the Arctic, 50 percent of the time it is dark, and for more than 30 percent of the daylight period the visibility is low due to fog, rain and snow. In summary you will not have human eye visibility for more than 65 percent of the year.
A: It results in signals from small and slow targets being emphasized, while sporadic signals are being suppressed.
This may be of great value for search and rescue.
The technology helps for early detection of possible dangerous vessels, e.g. speedboats or pirates.
Fast boats are then not detected by their spot positions, but by their bow or stern waves.
A: Rutter offers full, 24 hour e-mail client support to find and solve any potential problems. Usually, error log files and the configuration file have to be sent to Rutter. Screen shots of any error messages are also helpful.
Telephone support is available if e-mail support cannot resolve the issue. 
A: In general, installation takes 2-3 days, depending on the site and the preparation of the site for our purposes. When, for example, the radar is up running and the requested radar outputs are easily available to us, the installation can be done within a day.
To ensure as smooth an installation as possible for our clients, Rutter always seeks to establish concise and clear communication between our technical department and the customer.

FAQ - WaMos

A: The system can only measure currents when a certain sea state and a certain wind speed are available. That means if the waves are lower than 0.5-0.75 m, the radar backscatter is too weak and no analysis can be done. There is no limitation on the maximum. A wind speed of 3 m/s is required in addition.
A: The system calculates the significant wave height (Hs) which is defined as the mean over the highest third of all waves. Hs is a statistical parameter. Furthermore it is possible to separate the wave energy of the waves corresponding to swell and wind sea. WaMoS II can detect bimodal sea states. The peak wave system, which is the system with the highest wave energy, is shown on the left side of the GUI. On the right side of the GUI the information for each system (swell and wind sea) is given.
A: No. Current measurements are not affected by the ship’s movement. WaMoS is certified for ships that move up to 38 knots, both through te robustness of the system and the quality of the data.
A: The movement of the vessel does not affect the measurements and we do not need to apply any motion compensation. The system is type approved by Det Norske Veritas (DNV) and Germanischer Lloyd (GL), confirming the system’s functionality and robustness, as well as the accuracy of data collected on board vessels moving at speeds of up to 40 knots.
A: The largest radius is up to 4 km. WaMoS can be connected to most commercially available marine X-band radar.
The radar must operate in short pulse (near range), which corresponds to about 70 ns, otherwise the sea clutter reflections are too weak.
A: Minimum is 15 m; optimum is 25-60m
But we also have installations by having antenna heights up to 100 m.
A: The antenna should be mounted somewhere in the front part of the vessel, in order to have a minimum free viewing angle of 180 degrees. Best would be 270 degrees. But this is not mandatory.
A: For vessel WaMoS II needs the following NMEA input:
Ship speed over ground, track over ground, Gyro compass, GPS position, GPS time and water depth must be made available via NMEA (complying with NMEA 0183 standard).
Further information, i.e. wind speed and direction as NMEA input, is not mandatory but would valuable additional input.
A: It is feasible to install the WaMoS on a mobile platform. The antenna should be mounted a minimum of about 15m height over the sea level. (Higher always produces better results.)
A: Under various conditions, signatures of the sea surface are visible in the near range (< 3 nm) of nautical radar images. These signatures are known as sea clutter. The sea clutter is created by the backscatter of the transmitted electromagnetic waves from the short sea surface ripples (in the range of cm). The longer waves modulate the sea clutter signals and therefore become visible in the radar images.
Heavy rain showers have an effect on the roughness of ocean surface and therefore on the small ripples. The short surface ripples and, in this context, the sea clutter are getting disturbed by rain showers. The backscatter is different without rain.
A: WaMoS: 30W at either 110 or 220 volts
PC with LCD Monitor: approx. 200W
Radar, e.g. Kelvin Hughes 300W (250W in Standby)
A: Yes, WaMoS II recorded data will be stored and as well it can be exported out through a serial COM port in ASCII format.
A: The WaMoS II PC can be connected to a network and save all the recorded results on a server. This stored data can furthermore be accessed directly, via removable media, or on-line via modem/telephone or Internet.
A: For effective interpretation of the wave information, WaMoS II includes an internal quality control function that gives a quality index for each WaMoS II measurement. This index gives the user an easy tool to allow a reliability check of the data and to interpret its quality. The user gets the information regardless if the environmental conditions are sufficient for accurate radar wave measurements (e.g. if wind, rain or snowfall are degrading the quality of the images).
The quality control is carried out during the wave analysis and the index (IQ) is given in the header of the WaMoS II data products as well as listed for each data measurement in the time series.
A: OceanWaveS is available via e-mail at any time and gives full support to the client identify and and solve potential problems. Usually, error log files and the configuration file has to be sent to OceanWaveS. Screen shots of any error messages are also helpful.
The support can also be done via telephone if e-mail support is not sufficient enough. 
A: In general, the parts requiring the most maintenance are: PC mainboard, X-band radar coal brushes, X-band radar magnetron, net adapters and data communication infrastructure (e.g. Helgoland case). The radar parts have to be replaced every two years if the radar is running 24/7.
A: In general, the installation lasts for 2-3 days, depending on the site and the preparation of the site for our purposes. When, for example, the radar is up running and the requested radar outputs are easily available to us, the installation can be done within 1 day. It really depends a lot on the preparation on the site and a good communication between our technical department and the customer.
A: A calibration needs to be carried out for the estimation of the significant wave height only. All other sea state parameters are available directly from the system, without further calibration.
After the system has been installed by one of our engineers, he or she will already do a preliminary adjustment for the wave heights (depending on the prevailing conditions). WaMoS will then collect data over 7-14 days. (The best data always results from an increasing or decreasing wave/wind situation.) All data is stored on the PC and we would request some small files that can be sent by e-mail to us, with a reference source. Ideal would be a nearby in-situ data set or a numerical model output. We then calibrate the system and sent a new configuration file back that needs to be copied in the main directory. All information, which files are needed and where to copy the new configuration file will be given on the site during the installation process.
A: From the full radar image a defined number of rectangular sub areas (the ’analysis areas‘) are cut out. The WaMoS II wave analysis is carried out for these areas in order to guarantee full directional information. WaMoS II generates files for single measurements (spatially averaged over all WaMoS II analysis windows) as well as averaged data records (temporally averaged over a certain time).
Spatial averaging is accomplished according to the analysis areas (maximal 9 windows). The temporal averaging data records depend on the settings in the WaMoS II software (default setting: 20 minutes).
The WaMoS II data files ‘PARA’ and ‘PEAK’ are time series of the single measurement; the data files ‘MPAR’ and ‘MPEK’ are time series of temporally averaged measurement.
A: The Tabl gives names and symbols of the major sea state parameters and the corresponding ranges and accuracy provided by WaMoS II. The numbers are derived from direct comparisons between WaMoS II and independent in-situ sensors (e.g. laser, buoy).
​Environmental limitations: The imaging mechanism for waves in any kind of X-band radarrequires a minimum wind speed of 3 m/s, otherwise the waves are not reflected in the radar. In addition, significant wave heights below 0.5 m can not be resolved by the system. Heavy persistant rain showers will also not allow for wave measurments, as those disturb the reflecting ripple waves on the sea surface and the radar reflections become very strong.

*) There is no limit in estimating the wave heights, but up to now Hs of 14 m was the highest value measured with WaMoS® II​
**)These calues indicate the typical range by using an antenna with 1.4s repetition time. But it depends very much on the radar hardware, the total time of measurement and therefore can vary for each individual installation.
***) Based on comparative wave measurments taking into account an equally distributed error.