[Code of Federal Regulations]
[Title 33, Volume 2]
[Revised as of July 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 33CFR164.38]
[Page 621-626]
TITLE 33--NAVIGATION AND NAVIGABLE WATERS
CHAPTER I--COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED)
PART 164_NAVIGATION SAFETY REGULATIONS--Table of Contents
Sec. 164.38 Automatic radar plotting aids (ARPA).
(a) The following definitions are used in this section--
Bulk means material in any quantity that is shipped, stored, or
handled without benefit of package, label, mark or count and carried in
integral or fixed independent tanks.
Constructed means a stage of construction where--
(1) The keel is laid;
(2) Construction identifiable with a specific ship begins; or
(3) Assembly of that ship has commenced comprising at least 50 tons
or 1 percent of the estimated mass of all structural material, whichever
is less.
Hazardous material means--
(1) A flammable liquid as defined in 46 CFR 30.10-22 or a
combustible liquid as defined in 46 CFR 30.10-15;
(2) A material listed in table 151.05 of 46 CFR 151.05, table 1 of
46 CFR 153, or table 4 of 46 CFR Part 154; or
(3) A liquid, liquefied gas, or compressed gas listed in 49 CFR
172.101.
Self-propelled vessel includes those combinations of pushing vessel
and vessel being pushed ahead which are rigidly connected in a composite
unit and are required by Rule 24(b) of the International Regulations for
Preventing Collisions at Sea, 1972 (72 COLREGS) (App. A to 33 CFR Part
81) to exhibit the lights prescribed in Rule 23 for a ``Power Driven
Vessel Underway''.
Tank vessel means a vessel that is constructed or adapted to carry;
or carries, oil or hazardous materials in bulk as cargo or cargo
residue.
(b) An Automatic Radar Plotting Aid (ARPA) that complies with the
standard for such devices adopted by the International Maritime
Organization in its ``Operational Standards for Automatic Radar Plotting
Aids'' (Appendix A), and that has both audible and visual alarms, must
be installed as follows:
(1) Each self-propelled vessel, except a public vessel, of 10,000
gross tons or more carrying oil or hazardous materials in bulk as cargo
or in residue on the navigable waters of the United States, or which
transfers oil or hazardous materials in any port or place subject to the
jurisdiction of the United States, must be equipped with an ARPA.
(2) Each tank vessel of 10,000 gross tons or more operating on the
navigable waters of the United States must be equipped with an ARPA.
(3) Each self-propelled vessel of 15,000 gross tons or more that is
not a tank vessel, and is not carrying oil or hazardous material in bulk
as cargo or in residue operating on the navigable waters of the United
States, and was constructed before September 1, 1984, must be equipped
with an ARPA, except when it is operating on the Great Lakes and their
connecting and tributary waters.
(4) Each vessel of 10,000 gross tons or more, except when operating
on the Great Lakes and their connecting and tributary waters,
constructed on or after September 1, 1984 must be equipped with an ARPA.
(c) [Reserved]
(d)(1) Each device required under paragraph (b) of this section must
have a permanently affixed label containing:
(i) The name and address of the manufacturer; and
(ii) The following statement:
``This device was designed and manufactured to comply with the
International Maritime Organization (IMO) `Performance Standards for
Automatic Radar Plotting Aids (ARPA).' ''
(2) Each device allowed under paragraph (c) of this section must
have a permanently affixed label containing;
(i) The name and address of the manufacturer; and
(ii) The following statement:
``This device was designed and manufactured to comply with the U.S.
Maritime Administration's `Collision Avoidance System Specification.' ''
[[Page 622]]
Appendix A to Sec. 164.38--Performance Standards For Automatic Radar
Plotting Aids (ARPA)
1 Introduction
1.1 The Automatic Radar Plotting Aids (ARPA) should, in order to
improve the standard of collision avoidance at sea:
.1 Reduce the work-load of observers by enabling them to
automatically obtain information so that they can perform as well with
multiple targets as they can by manually plotting a single target; and
.2 Provide continuous, accurate and rapid situation evaluation.
1.2 In addition to the General Requirements for Electronic
Navigational Aids ([IMO] Res. A.281(VII)), the ARPA should comply with
the following minimum performance standards.
2 Definitions
2.1 Definitions of terms in these performance standards are given in
Annex 1.
3 Performance Standards
3.1 Detection
3.1.1 Where a separate facility is provided for detection of
targets, other than by the radar observer, it should have a performance
not inferior to that which could be obtained by the use of the radar
display.
3.2 Acquisition
3.2.1 Target acquisition may be manual or automatic. However, there
should always be a facility to provide for manual acquisition and
cancellation. ARPA with automatic acquisition should have a facility to
suppress acquisition in certain areas. On any range scale where
acquisition is suppressed over a certain area, the area of acquisition
should be indicated on the display.
3.2.2 Automatic or manual acquisition should have a performance not
inferior to that which could be obtained by the user of the radar
display.
3.3 Tracking
3.3.1 The ARPA should be able to automatically track, process,
simultaneously display and continuously update the information on at
least:
.1 20 targets, if automatic acquisition is provided, whether
automatically or manually acquired; or
.2 10 targets, if only manual acquisition is provided.
3.3.2 If automatic acquisition is provided, description of the
criteria of selection of targets for tracking should be provided to the
user. If the ARPA does not track all targets visible on the display,
targets which are being tracked should be clearly indicated on the
display. The reliability of tracking should not be less than that
obtainable using manual recording of successive target positions
obtained from the radar display.
3.3.3 Provided the target is not subject to target swop, the ARPA
should continue to track an acquired target which is clearly
distinguishable on the display for 5 out of 10 consecutive scans.
3.3.4 The possibility of tracking errors, including target swop,
should be minimized by ARPA design. A qualitative description of the
effects of error sources on the automatic tracking and corresponding
errors should be provided to the user, including the effects of low
signal to noise and low signal to clutter ratios caused by sea returns,
rain, snow, low clouds and non-synchronous emission.
3.3.5 The ARPA should be able to display on request at least four
equally time-spaced past positions of any targets being tracked over a
period of at least eight minutes.
3.4 Display
3.4.1 The Display may be a separate or integral part of the ship's
radar. However, the ARPA display should include all the data required to
be provided by a radar display in accordance with the performance
standards for navigational radar equipment adopted by the Organization.
3.4.2 The design should be such that any malfunction of ARPA parts
producing information additional to information to be produced by the
radar as required by the performance standards for navigational
equipment adopted by IMO should not affect the integrity of the basic
radar presentation.
3.4.3 The display on which ARPA information is presented should have
an effective diameter of at least 340 mm.
3.4.4 The ARPA facilities should be available on at least the
following range scales:
.1 12 or 16 miles;
.2 3 or 4 miles.
3.4.5 There should be a positive indication of the range scale in
use.
3.4.6 The ARPA should be capable of operating with a relative motion
display with ``north-up'' and either ``head-up'' or ``course-up''
azimuth stabilization. In addition, the ARPA may also provide for a true
motion display. If true motion is provided, the operator should be able
to select for his display either true or relative motion. There should
be a positive indication of the display mode and orientation in use.
3.4.7 The course and speed information generated by the ARPA for
acquired targets should be displayed in a vector or graphic form which
clearly indicates the target's predicted motion. In this regard:
.1 ARPA presenting predicted information in vector form only should
have the option of both true and relative vectors;
.2 An ARPA which is capable of presenting target course and speed
information in graphic form, should also, on request, provide the
target's true and/or relative vector;
[[Page 623]]
.3 Vectors displayed should be either time adjustable or have a
fixed time-scale;
.4 A positive indication of the time-scale of the vector in use
should be given.
3.4.8 The ARPA information should not obscure radar information in
such a manner as to degrade the process of detecting targets. The
display of ARPA data should be under the control of the radar observer.
It should be possible to cancel the display of unwanted ARPA data.
3.4.9 Means should be provided to adjust independently the
brilliance of the ARPA data and radar data, including complete
elimination of the ARPA data.
3.4.10 The method of presentation should ensure that the ARPA data
is clearly visible in general to more than one observer in the
conditions of light normally experienced on the bridge of a ship by day
and by night. Screening may be provided to shade the display from
sunlight but not to the extent that it will impair the observer's
ability to maintain a proper lookout. Facilities to adjust the
brightness should be provided.
3.4.11 Provisions should be made to obtain quickly the range and
bearing of any object which appears on the ARPA display.
3.4.12 When a target appears on the radar display and, in the case
of automatic acquisition, enters within the acquisition area chosen by
the observer or, in the case of manual acquisition, has been acquired by
the observer, the ARPA should present in a period of not more than one
minute an indication of the target's motion trend and display within
three minutes the target's predicted motion in accordance with
paragraphs 3.4.7, 3.6, 3.8.2 and 3.8.3.
3.4.13 After changing range scales on which the ARPA facilities are
available or resetting the display, full plotting information should be
displayed within a period of time not exceeding four scans.
3.5 Operational Warnings
3.5.1 The ARPA should have the capability to warn the observer with
a visual and/or audible signal of any distinguishable target which
closes to a range or transits a zone chosen by the observer. The target
causing the warning should be clearly indicated on the display.
3.5.2 The ARPA should have the capability to warn the observer with
a visual and/or audible signal of any tracked target which is predicted
to close to within a minimum range and time chosen by the observer. The
target causing the warning should be clearly indicated on the display.
3.5.3 The ARPA should clearly indicate if a tracked target is lost,
other than out of range, and the target's last tracked position should
be clearly indicated on the display.
3.5.4 It should be possible to activate or de-activate the
operational warnings.
3.6 Data Requirements
3.6.1 At the request of the observer the following information
should be immediately available from the ARPA in alphanumeric form in
regard to any tracked target:
1. Present range to the target;
2. Present bearing of the target;.
.3 Predicted target range at the closest point of approach (CPA);
.4 Predicted time to CPA (TCPA);
.5 Calculated true course of target;
.6 Calculated true speed of target.
3.7 Trial Manoeuvre
3.7.1 The ARPA should be capable of simulating the effect on all
tracked targets of an own ship manoeuvre without interrupting the
updating of target information. The simulation should be initiated by
the depression either of a spring-loaded switch, or of a function key,
with a positive identification on the display.
3.8 Accuracy
3.8.1 The ARPA should provide accuracies not less than those given
in paragraphs 3.8.2 and 3.8.3 for the four scenarios defined in Annex 2.
With the sensor errors specified in Annex 3, the values given relate to
the best possible manual plotting performance under environmental
conditions of plus and minus ten degrees of roll.
3.8.2 An ARPA should present within one minute of steady state
tracking the relative motion trend of a target with the following
accuracy values (95 percent probability values):
------------------------------------------------------------------------
Relative Relative
Scenario/data course speed CPA (n.m.)
(degrees) (Knots)
------------------------------------------------------------------------
1................................ 11 2.8 1.6
2................................ 7 0.6 ...........
3................................ 14 2.2 1.8
4................................ 15 1.5 2.0
------------------------------------------------------------------------
3.8.3 An ARPA should present within three minutes of steady state
tracking the motion of a target with the following accuracy values (95
percent probability values):
----------------------------------------------------------------------------------------------------------------
Relative Relative True
Scenario/data course speed C.P.A. TCPA course True speed
(degrees) (knots) (n.m.) (mins) (degrees) (knots)
----------------------------------------------------------------------------------------------------------------
1....................................... 3.0 0.8 0.5 1.0 7.5 1.2
2....................................... 2.3 .3 .......... .......... 2.9 .8
3....................................... 4.4 .9 .7 1.0 3.3 1.0
4....................................... 4.6 .8 .7 1.0 2.6 1.2
----------------------------------------------------------------------------------------------------------------
[[Page 624]]
3.8.4 When a tracked target, or own ship, has completed a manoeuvre,
the system should present in a period of not more than one minute an
indication of the target's motion trend, and display within three
minutes the target's predicted motion in accordance with paragraphs
3.4.7, 3.6, 3.8.2 and 3.8.3
3.8.5 The ARPA should be designed in such a manner that under the
most favorable conditions of own ship motion the error contribution from
the ARPA should remain insignificant compared to the errors associated
with the input sensors, for scenarios of Annex 2.
3.9 Connections with other equipment
3.9.1 The ARPA should not degrade the performance of any equipment
providing sensor inputs. The connection of the ARPA to any other
equipment should not degrade the performance of that equipment.
3.10 Performance test and warnings
3.10.1 The ARPA should provide suitable warnings of ARPA malfunction
to enable the observer to monitor the proper operation of the system.
Additionally test programmes should be available so that the overall
performance of ARPA can be assessed periodically against a known
solution.
3.11 Equipment used with ARPA
3.11.1 Log and speed indicators providing inputs to ARPA equipment
should be capable of providing the ship's speed through the water.
Annex 1 to Appendix A--Definitions of Terms To Be Used Only in
Connection With ARPA Performance Standards
Relative course--The direction of motion of a target related to own
ship as deduced from a number of measurements of its range and bearing
on the radar. Expressed as an angular distance from North.
Relative speed--The speed of a target related to own ship, as
deduced from a number of measurements of its range and bearing on the
radar.
True course--The apparent heading of a target obtained by the
vectorial combination of the target's relative motion and ship's own
motion \1\. Expressed as an angular distance from North.
---------------------------------------------------------------------------
\1\ For the purpose of these definitions there is no need to
distinguish between sea or ground stabilization.
---------------------------------------------------------------------------
True speed--The speed of a target obtained by the vectorial
combination of its relative motion and own ship's motion \1\.
Bearing--The direction of one terrestrial point from another.
Expressed as an angular distance from North.
Relative motion display--The position of own ship on such a display
remains fixed.
True motion display--The position of own ship on such display moves
in accordance with its own motion.
Azimuth stabilization--Own ship's compass information is fed to the
display so that echoes of targets on the display will not be caused to
smear by changes of own ship's heading.
/North-up--The line connecting the center with the top of this display
is North.
/Head-up--The line connecting the center with the top of the display is
own ship heading.
/Course-up--An intended course can be set to the line connecting the
center with the top of the display.
Heading--The direction in which the bow of a vessel is pointing.
Expressed as an angular distance from North.
Target's predicted motion--The indication on the display of a liner
extrapolation into the future of a target's motion, based on
measurements of the target's range and bearing on the radar in the
recent past.
Target's motion trend--An early indication of the target's predicted
motion.
Radar Plotting--The whole process of target detection, tracking,
calculation of parameters and display of information.
Detection--The recognition of the presence of a target.
Acquisition--The selection of those targets requiring a tracking
procedure and the initiation of their tracking.
Tracking--The process of observing the sequential changes in the
position of a target, to establish its motion.
Display--The plan position presentation of ARPA data with radar
data.
Manual--An activity which a radar observer performs, possibly with
assistance from a machine.
Automatic--An activity which is performed wholly by a machine.
Annex 2 to Appendix A--Operational Scenarios
For each of the following scenarios predictions are made at the
target position defined after previously tracking for the appropriate
time of one or three minutes:
Scenario 1
Own ship course--000[deg]
Own ship speed--10 kt
Target range--8 n.m.
Bearing of target--000[deg]
Relative course of target--180[deg]
Relative speed of target--20 kt
Scenario 2
Own ship course--000[deg]
Own ship speed--10 kt
Target range--1 n.m.
Bearing of target--000[deg]
Relative course of target--090[deg]
Relative speed of target--10 kt
[[Page 625]]
Scenario 3
Own ship course--000[deg]
Own ship speed--5 kt
Target range--8 n.m.
Bearing of target--045[deg]
Relative course of target--225[deg]
Relative speed of target--20 kt
Scenario 4
Own ship course--000[deg]
Own ship speed--25 kt
Target range--8 n.m.
Bearing of target--045[deg]
Relative course of target--225[deg]
Relative speed of target--20 kt
Annex 3 to Appendix A--Sensor Errors
The accuracy figures quoted in paragraph 3.8 are based upon the
following sensor errors and are appropriate to equipment complying with
the Organization's performance standards for shipborne navigational
equipment.\2\
---------------------------------------------------------------------------
\2\ In calculations leading to the accuracy figures quoted in
paragraph 3.8, these sensor error sources and magnitudes were used. They
were arrived at during discussions with national government agencies and
equipment manufacturers and are appropriate to equipments complying with
the Organization's draft performance standards for radar equipment
(preliminary) (NAV XXII/WP.14), gyro compasses (NAV XXI/9, Annex X) and
logs (preliminary) (NAV XXII/WP.15).
Independent studies carried out by national government agencies and
equipment manufacturers have resulted in similar accuracies, where
comparisons were made.
Note: o means ``standard deviation''
Radar
Target Glint (Scintillation) (for 200 m length target)
Along length of target o = 30 m. (normal distribution)
Across beam of target o = 1 m. (normal distribution)
Roll-Pitch Bearing. The bearing error will peak in each of the four
quadrants around own ship for targets on relative bearings of 045[deg],
135[deg], 225[deg] and 315[deg] and will be zero at relative bearings of
0[deg], 90[deg], 180[deg] and 270[deg]. This error has a sinusoidal
variation at twice the roll frequency. For a 10[deg] roll the mean error
is 0.22[deg] with a 0.22[deg] peak sine wave superimposed.
Beam shape--assumed normal distribution giving bearing error with o
= 0.05.
Pulse shape-- assumed normal distribution giving range error with o
= 20 meters.
Antenna backlash--assumed rectangular distribution giving bearing
error 0.5 maximum.
Quantization
Bearing--rectangular distribution 0.01[deg]
maximum.
Range--rectangular distribution 0.01 n.m.
maximum.
Bearing encoder assumed to be running from a remote synchro giving
bearing errors with a normal distribution o = 0.03[deg]
Gyro compass
Calibration error 0.5[deg].
Normal distribution about this with o = 0.12[deg].
Log
Calibration error 0.5 kt.
Normal distribution about this, 3 o = 0.2 kt.
Appendix B to Sec. 164.38--U.S. Maritime Administration Collision
Avoidance System Specification
A collision system designed as a supplement to both surface search
navigational radars via interswitching shall be installed. The system
shall provide unattended monitoring of all radar echoes and automatic
audio and visual alarm signals that will alert the watch officer of a
possible threat. The display shall be contained within a console capable
of being installed adjacent to the radar displays in the wheelhouse and
may form a part of the bridge console.
Provision for signal input from the ship's radars, gyro compass, and
speed log, without modification to these equipments shall be made. The
collision avoidance system, whether operating normally or having failed,
must not introduce any spurious signals or otherwise degrade the
performance of the radars, the gyro compass or the speed log.
Computer generated display data for each acquired target shall be in
the form of a line or vector indicating true or relative target course,
speed and both present and extrapolated future positions. Data shall be
automatically displayed on a cathode ray tube or other suitable display
contrivance sufficiently bright and unobstructed to permit viewing by
more than one person at a time.
In addition to displaying the collision potential of the most
threatening fixed and moving targets, the system shall be capable of
simultaneously showing land masses.
The system display shall include a heading indication and bearing
ring. The system shall also have the capability of allowing the operator
to select ``head-up'' and to cancel the vector or line presentation of
any of the targets. The presentation shall be non-smearing when changing
modes or display scales in order to permit rapid evaluation of the
displayed data.
Target acquisition, for display data purposes, may be manual,
automatic or both, as specified by Owner.
[[Page 626]]
For any manual acquisition system the alarms shall be initiated by a
preset minimum range; and likewise for any automatic acquisition system
the alarms shall be initiated by a preset minimum acceptable passing
distance (CPA--Closest Point of Approach) and a preset advance warning
time (TCPA--Time to Closest Point of Approach). Means shall be provided
to silence the audio alarm for a given threat but the alarm shall
resound upon a subsequent threat. The visual alarm shall continue to
operate until all threats have been eliminated. If the collision
avoidance system fails to perform as indicated above, after the system
is set for unattended monitoring, the system shall produce both audio
and visual warning alarms.
The system shall be capable of simulating a trial maneuver.
In addition to the target display, an alpha-numeric readout shall be
provided which can present range, bearing, course, speed, CPA and TCPA
for any selected target, either on the target display or by other
display means.
The collision avoidance system shall be energized from the interior
communications panel board in the wheelhouse.
The collision avoidance function may be incorporated in an
integrated conning system, provided that failure of any other integrated
system component will not degrade the collision avoidance function.
[CGD 79-148, 45 FR 54039, Aug. 14, 1980; 45 FR 71800, Oct. 30, 1980, as
amended by CGD 83-004, 49 FR 43467, Oct. 29, 1984; USCG-1998-3799, 63 FR
35532, June 30, 1998]