RADAR is an integral part of Navigational Equipment. And a piece of most used equipment used at the bridge. With proper use, RADAR is the best tool to avoid the collision.
Table of Contents
- SOLAS Requirements for RADAR:
- Application of Performance Standards of RADAR
- Operational Requirements:
- Back-up and Fallback Arrangements
- Input Data Integrity and Latency of Radar
- Output Data by Radar
- Instructions and Documentation
SOLAS Requirements for RADAR:
Chp. V/ Reg 19.2.3 of SOLAS:
– All ships of 300 GRT and upwards and passenger ships irrespective of size shall have a 9 GHz RADAR or other means to determine and display the range and bearing of radar transponders and of other surface craft, obstructions, buoys, shorelines, and navigational marks to assist in navigation and in collision avoidance;
Chp. V/ Reg 19.2.5 of SOLAS:
-An automatic tracking aid, or other means, to plot automatically the range and bearing of other targets to determine collision risk.
Chp. V/ Reg 19.2.7 of SOLAS:– RADAR Requirements as per SOLAS Chp V
– A 3 GHz RADAR or where considered appropriate by the Administration a second 9 GHz RADAR, or other means to determine and display the range and bearing of other surface craft, obstructions, buoys, shorelines and navigational marks to assist in navigation and in collision avoidance
a second automatic tracking aid, or other means to plot automatically the range and bearing of other targets to determine collision risk which are functionally independent of those referred to in paragraph 2.5.5 of SOLAS Chp V/ Reg 19.
For these RADARs to work as per the standard the IMO has outlined Performance Standards for RADAR Equipment on board. These Performance Standards were revised under Res. MSC.192(79) and adopted on 6 December 2004.
Application of Performance Standards of RADAR
These Performance Standards should apply to all shipborne RADAR installations, used in any configuration, mandated by the SOLAS 1974:
- type of ship;
- the frequency band in use; and
- type of display
providing that no special requirements are specified and that additional requirements for specific classes of ships (in accordance with SOLAS chapters V and X) are met.
The radar installation, in addition to meeting the general requirements as set out in Resolution A.694(17)*, should comply with the following performance standards.
The RADAR equipment should assist in safe navigation and in avoiding collision by providing an indication, in relation to own ship, of the position of other surface craft, obstructions and hazards, navigation objects and shorelines.
The RADAR combined with other sensor or reported information (e.g. AIS), should improve the safety of navigation by assisting in the efficient navigation of ships and protection of the environment by satisfying the following functional requirements:
- in coastal navigation and harbor approaches, by giving a clear indication of land and other fixed hazards;
- as a means to provide an enhanced traffic image and improved situation awareness;
- in a ship-to-ship mode for aiding collision avoidance of both detected and reported hazards;
- in the detection of small floating and fixed hazards, for collision avoidance and the safety of own ship; and
- in the detection of floating and fixed aids to navigation
Frequency: The radar should transmit within the confines of the ITU allocated bands for maritime radar and meet the requirements of the radio regulations and applicable ITU-R recommendations.
Radar Range and Bearing Accuracy: The RADAR Range accuracy should be within 30 m or 1% of the range scale in use, whichever is greater. And for bearing the accuracy should be within 1%.
Detection in Clear Conditions: In the absence of clutter, for long-range targets and shoreline detection, the requirement for Performance Standard of Radar is based on normal propagation conditions, in the absence of sea clutter, precipitation and evaporation duct, with an antenna height of 15 m above sea level.
– an indication of the target in at least 8 out of 10 scans or equivalent; and
– a probability of a radar detection false alarm of 10-4
The detection performance should be achieved using the smallest antenna that is supplied with the radar system.
Detection at Close Range:
The short-range detection of the targets under the various conditions should be compatible with the requirement of Minimum Range. Detection in Clutter Conditions:
- The RADAR equipment should be designed to provide the optimum and most consistent detection performance, restricted only by the physical limits of propagation.
- The RADAR should provide the means to enhance the visibility of targets in adverse clutter conditions at close range.
Gain and Anti-Clutter Functions:
- Means should be provided, as far as is possible, for the adequate reduction of unwanted echoes, including sea clutter, rain and other forms of precipitation, clouds, sandstorms, and interference from other radars.
- A gain control function should be provided to set the system gain or signal threshold level.
- Effective manual and automatic anti-clutter functions should be provided.
- A combination of automatic and manual anti-clutter functions is permitted.
- There should be a clear and permanent indication of the status and level for gain and all anti-clutter control functions.
- With own ship at zero speed, an antenna height of 15 m above the sea level and in calm conditions, a navigational buoy (see table) should be detected at a minimum horizontal range of 40 m from the antenna position and up to a range of 1 nm, without changing the setting of control functions other than the range scale selector.
- Compensation for any range error should be automatically applied for each selected antenna, where multiple antennas are installed.
- Discrimination: Range and bearing discrimination should be measured in calm conditions, on a range scale of 1.5 NM or less and at between 50% and 100% of the range scale selected:
- Range: As per Performance Standards of RADAR, a Radar system should be capable of displaying two-point targets on the same bearing, separated by 40 m in range, as two distinct objects.
- Bearing: The radar system should be capable of displaying two-point targets at the same range, separated by 2.5° in bearing, as two distinct objects.
- Roll and Pitch: The target detection performance of the equipment should not be substantially impaired when own ship is rolling or pitching up to +/-10°.
- Display Range Scales: Range scales of 0.25, 0.5, 0.75, 1.5, 3, 6, 12 and 24 NM should be provided. Additional range scales are permitted outside the mandatory set. Low metric range scales may be offered in addition to the mandatory set. The range scale selected should be permanently indicated on the display.
- Radar Availability:
- The radar equipment should be fully operational (RUN status) within 4 minutes after switch ON from cold.
- A STANDBY condition should be provided, in which there is no operational radar transmission. The radar should be fully operational within 5 sec from the standby condition.
Operation with SARTs and Radar Beacons
- The X-Band RADAR system should be capable of detecting RADAR Beacons in the relevant frequency band.
- The X-Band RADAR system should be capable of detecting SARTs and radar target enhancers.
- It should be possible to switch off those signal processing functions, including polarization modes, which might prevent an X-Band RADAR Beacon or SARTs from being detected and displayed. The status should be indicated on the display.
Fixed Range Rings:
- An appropriate number of equally spaced range rings should be provided for the range scale selected. When displayed, the range ring scale should be indicated.
- The system accuracy of fixed range rings should be within 1% of the maximum range of the range scale in use or 30 m, whichever is the greater distance.
Variable Range Markers (VRM)
- At least two variable range markers (VRMs) should be provided. Each active VRM should have a numerical readout and have a resolution compatible with the range scale in use.
- The VRMs should enable the user to measure the range of an object within the operational display area with a maximum system error of 1% of the range scale in use or 30 m, whichever is the greater distance.
- A bearing scale around the periphery of the operational display area should be provided. The bearing scale should indicate the bearing as seen from the consistent common reference point.
- The bearing scale should be outside of the operational display area. It should be numbered at least every 30° division and have division marks of at least 5°.
- The 5° and 10° division marks should be clearly distinguishable from each other. 1° division marks may be presented where they are clearly distinguishable from each other.
Heading Line (HL)
- A graphic line from the consistent common reference point to the bearing scale should indicate the heading of the ship.
- Electronic means should be provided to align the heading line to within 0.1°. If there is more than one radar antenna the heading skew (bearing offset) should be retained and automatically applied when each radar antenna is selected.
- Provision should be made to temporarily suppress the heading line. This function may be combined with the suppression of other graphics.
Electronic Bearing Lines (EBLs)
- At least two electronic bearing lines (EBL’s) should be provided to measure the bearing of any object within the operational display area, with a maximum system error of 1° at the periphery of the display.
- The EBLs should be capable of measurement relative to the ships heading and relative to true north. There should be a clear indication of the bearing reference (i.e. true or relative).
- It should be possible to move the EBL origin from the consistent common reference point to any point within the operational display area and to reset the EBL to the consistent common reference point by a fast and simple action.
- It should be possible to fix the EBL origin or to move the EBL origin at the velocity of own ship.
- Means should be provided to ensure that the user is able to position the EBL smoothly in either direction, with an incremental adjustment adequate to maintain the system measurement accuracy requirements.
- Each active EBL should have a numerical readout with a resolution adequate to maintain the system measurement accuracy requirements.
Parallel Index lines (PI)
- A minimum of four independent parallel index lines, with a means to truncate and switch off individual lines, should be provided.
- Simple and quick means of setting the bearing and beam range of a parallel index line should be provided. The bearing and beam range of any selected index line should be available on demand.
Display Mode of the Radar Picture
- A True Motion display mode should be provided. The automatic reset of own ship may be initiated by its position on the display, or time-related, or both.
- Where the reset is selected to occur at least on every scan or equivalent, this should be equivalent to True Motion with a fixed origin (in practice equivalent to the previous relative motion mode).
- North Up and Course Up orientation modes should be provided. Head-Up may be provided when the display mode is equivalent to True Motion with a fixed origin (in practice equivalent to the previous relative motion Head-Up mode).
- An indication of the motion and orientation mode should be provided.
- Manual off-centering should be provided to locate the selected antenna position at any point within at least 50% of the radius from the center of the operational display area.
- On selection of off-centered display, the selected antenna position should be capable of being located to any point on the display up to at least 50%, and not more than 75%, of the radius from the center of the operational display area.
- A facility for automatically positioning own ship for the maximum view ahead may be provided.
- n True Motion, the selected antenna position should automatically reset up to a 50% radius to a location giving the maximum view along its own shipís course. Provision for an early reset of the selected antenna position should be provided.
Ground and Sea Stabilization Modes
- The Radar should be provided with Ground and Sea stabilization modes
- The stabilization mode and stabilization source should be clearly indicated.
- The source of own ships’ speed should be indicated and provided by a sensor approved in accordance with the requirements of IMO for the relevant stabilization mode.
- The RADAR should be integrated with Gyro or by an equivalent sensor for heading information.
- Excluding the limitations of the stabilizing sensor and type of transmission system, the accuracy of azimuth alignment of the radar presentation should be within 0.5° with a rate of turn likely to be experienced with the class of ship.
- The heading information should be displayed with a numerical resolution to permit accurate alignment with the ship gyro system.
- The heading information should be referenced to the consistent common reference point (CCRP).
- Proper means should be provided to enhance the target presentation on the display.
- The effective picture update period should be adequate, with the minimum required span of time to ensure that the target detection requirements are met.
- The picture on the display should be updated in a smooth and continuous manner.
- The equipment manual provided by the manufacturer should explain the basic concept, features, and limitations of any signal processing.
Radar Performance Optimization and Tuning
- Means should be available to ensure that the radar system is operating at the best performance. Where applicable to the radar technology, manual tuning should be provided and additionally, automatic tuning may be provided.
- An indication should be provided, in the absence of targets, to ensure that the system is operating at the optimum performance.
- Means should be available (automatically or by manual operation) and while the equipment is operational, to determine a significant drop in system performance relative to a calibrated standard established at the time of installation.
- A user cursor should be provided to enable a fast and concise means to designate any position on the operational display area.
- The cursor position should have a continuous readout to provide the range and bearing, measured from the consistent common reference point, and/or the latitude and longitude of the cursor position presented either alternatively or simultaneously.
- The cursor should provide the means to select and de-select targets, graphics or objects within the operational display area. In addition, the cursor may be used to select modes, functions, vary parameters and control menus outside of the operational display area.
- Means should be provided to easily locate the cursor position on the display.
- The accuracy of the range and bearing measurements provided by the cursor should meet the relevant requirements for VRM and EBL.
Back-up and Fallback Arrangements
In the event of partial failures and to maintain minimum basic operation, the fallback arrangements listed below should be provided. There should be a permanent indication of the failed input information.
- Failure of Heading Information (Azimuth Stabilization)
- The equipment should operate satisfactorily in an unstabilized head-up mode.
- The equipment should switch automatically to the unstabilized head-up mode within one minute after the azimuth stabilization has become ineffective.
- If automatic anti-clutter processing could prevent the detection of targets in the absence of appropriate stabilization, the processing should switch off automatically within 1 minute after the azimuth stabilization has become ineffective.
- An indication should be given that only relative bearing measurements can be used.
- Failure of Speed through the Water Information: A means of manual speed input should be provided and its use clearly indicated.
- Failure of Course and Speed Over Ground Information: The equipment may be able to be operated with course and speed through the water information.
- Failure of Position Input Information: The overlay of chart data and geographically referenced maps should be disabled if only a single Reference Target is defined and used, or the position is manually entered.
- Failure of Radar Video Input Information: In the absence of radar signals, the equipment should display target information based on AIS data. A frozen radar picture should not be displayed.
- Failure of AIS Input Information: In the absence of AIS signals, the equipment should display the radar video and target database.
- Failure of an Integrated or Networked System: The equipment should be capable of operating equivalent to a stand-alone system.
Input Data Integrity and Latency of Radar
- The radar system should not use data indicated as invalid. If input data is known to be of poor quality this should be clearly indicated.
- As far as is practical, the integrity of data should be checked, prior to its use, by comparison with other connected sensors or by testing to valid and plausible data limits.
- The latency of processing input data should be minimized.
Output Data by Radar
- Information provided by any radar output interface to other systems should be in accordance with international standards (Refer to IEC publication 61162).
- The radar system should provide an output of the display data for the voyage data recorder (VDR).
- At least one normally closed contact (isolated) should be provided for indicating failure of the radar.
- The radar should have a bi-directional interface to facilitate communication so that alarms from the radar can be transferred to external systems and so that audible alarms from the radar can be muted from external systems, the interface should comply with relevant international standards.
Instructions and Documentation
- Documentation Language: The operating instructions and manufacturerís documentation should be written in a clear and comprehensible manner and should be available at least in the English language.
- Operating Instructions: The operating instructions should contain a qualified explanation and/or description of the information required by the user to operate the radar system correctly, including:
- appropriate settings for different weather conditions;
- monitoring the radar systemís performance;
- operating in a failure or fall-back situation;
- limitations of the display and tracking process and accuracy, including any delays;
- using heading and SOG/COG information for collision avoidance;
- limitations and conditions of target association;
- criteria of selection for automatic activation and cancellation of targets;
- methods applied to display AIS targets and any limitations;
- principles underlying the trial maneuver technology, including simulation of own shipís maneuvering characteristics, if provided;
- alarms and indications;
- installation requirements
- radar range and bearing accuracies; and
- any special operation (e.g. tuning) for the detection of SARTs; and
- the role of the CCRP for radar measurements and its specific value.
Reference: IMO Website and RESOLUTION MSC.192(79)