IEC 60872-1:1998

INTERNATIONAL
IEC
STANDARD
60872-1
First edition
1998-09
Maritime navigation and radiocommunication
equipment and systems – Radar plotting aids –
Part 1:
Automatic radar plotting aids (ARPA) –
Methods of testing and required test results
Matériels et systèmes de navigation et de radiocommunication
maritimes – Aides de pointage radar –
Partie 1:
Aides de pointage radar automatiques (APRA) – Méthodes
d’essai et résultats d’essai exigés

Reference number
Numbering
As from 1 January 1997 all IEC publications are issued with a designation in the
60000 series.
Consolidated publications
Consolidated versions of some IEC publications including amendments are

available. For example, edition numbers 1.0, 1.1 and 1.2 refer, respectively, to the
base publication, the base publication incorporating amendment 1 and the base

publication incorporating amendments 1 and 2.

Validity of this publication
The technical content of IEC publications is kept under constant review by the IEC,
thus ensuring that the content reflects current technology.
Information relating to the date of the reconfirmation of the publication is available
in the IEC catalogue.
Information on the subjects under consideration and work in progress undertaken by
the technical committee which has prepared this publication, as well as the list of
publications issued, is to be found at the following IEC sources:
• IEC web site*
• Catalogue of IEC publications
Published yearly with regular updates
(On-line catalogue)*
• IEC Bulletin
Available both at the IEC web site* and as a printed periodical
Terminology, graphical and letter symbols
For general terminology, readers are referred to IEC 60050: International
Electrotechnical Vocabulary (IEV).
For graphical symbols, and letter symbols and signs approved by the IEC for
general use, readers are referred to publications IEC 60027: Letter symbols to be
used in electrical technology, IEC 60417: Graphical symbols for use on equipment.
Index, survey and compilation of the single sheets and IEC 60617: Graphical symbols
for diagrams.
* See web site address on title page.

INTERNATIONAL
IEC
STANDARD
60872-1
First edition
1998-09
Maritime navigation and radiocommunication
equipment and systems – Radar plotting aids –
Part 1:
Automatic radar plotting aids (ARPA) –
Methods of testing and required test results
Matériels et systèmes de navigation et de radiocommunication
maritimes – Aides de pointage radar –
Partie 1:
Aides de pointage radar automatiques (APRA) – Méthodes
d’essai et résultats d’essai exigés

 IEC 1998  Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or
mechanical, including photocopying and microfilm, without permission in writing from the publisher.
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International Electrotechnical Commission
For price, see current catalogue

– 2 – 60872-1 © IEC:1998(E)
CONTENTS
Page
FOREWORD . 3

Clause
1 Scope. 4

2 Normative references. 4

3 Performance requirements. 5
3.1 Introduction . 5
3.2 Definitions . 6
3.3 Performance standards. 6
4 Methods of testing and required test results . 12
4.1 General . 12
4.2 Detection, acquisition, tracking and general facilities. 12
4.3 Tracking reliability. 14
4.4 Tracking accuracy . 15
4.5 Closing target warning . 15
4.6 Collision risk (CPA/TCPA) warning. 16
4.7 Trial manoeuvre . 16
4.8 Display . 16
4.9 Audible warnings . 16
4.10 Data requirements . 17
4.11 Interfaces . 17
4.12 Performance test and warnings. 17
4.13 Sea and ground stabilization . 17
4.14 System configuration and quality assurance . 17
Annexes
A Definition of terms to be used in connection with ARPA performance standards. 18

B Operational scenarios . 21
C Sensor errors. 22
D ARPA testing using simulated targets. 24
E Electronic plotting video symbols (EPVS) . 25

60872-1 © IEC:1998(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION

___________
MARITIME NAVIGATION AND RADIOCOMMUNICATION

EQUIPMENT AND SYSTEMS –
RADAR PLOTTING AIDS –
Part 1: Automatic radar plotting aids (ARPA) –

Methods of testing and required test results

FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International Organization
for Standardization (ISO) in accordance with conditions determined by agreement between the two
organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical reports or guides and they are accepted by the National Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60872-1 has been prepared by IEC technical committee 80:
Maritime navigation and radiocommunication equipment and systems. The IEC 60872 series,
of which this is part 1, replaces IEC 60872 published in 1987 and amendment 1 (1991) and
reflects the new requirements of the International Maritime Organization (IMO).

The text of this standard is based on the following documents:
FDIS Report on voting
80/192/FDIS 80/207/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
Annexes A, B, C, D and E form an integral part of this standard.
A bilingual version of this standard may be issued at a later date.

– 4 – 60872-1 © IEC:1998(E)
MARITIME NAVIGATION AND RADIOCOMMUNICATION

EQUIPMENT AND SYSTEMS –
RADAR PLOTTING AIDS –
Part 1: Automatic radar plotting aids (ARPA) –

Methods of testing and required test results

1 Scope
This International Standard specifies the minimum operational and performance requirements,
methods of testing and test results for equipment that complies with performance standards not
inferior to those adopted by the International Maritime Organization (IMO) in Resolution A.823.
In addition, this standard takes account of IMO Resolution A.694 and is associated with
IEC 60945.
When a requirement in this standard is different from IEC 60945, the requirement in this
standard shall take precedence.
All texts of this standard, in which the wording is identical to that in IMO Resolution A.823, are
printed in italics and the resolution and paragraph numbers are indicated in brackets.
2 Normative references
The following normative documents contain provisions which, through reference in this text,
constitute provisions of this part of IEC 60872. At the time of publication, the editions indicated
were valid. All normative documents are subject to revision, and parties to agreements based
on this part of IEC 60872 are encouraged to investigate the possibility of applying the most
recent editions of the normative documents indicated below. Members of IEC and ISO maintain
registers of currently valid International Standards.
IEC 60872-2,— Maritime navigation and radiocommunication equipment and systems – Radar
plotting aids – Part 2: Automatic tracking aids (ATA) – Methods of testing and required test
1)
results
IEC 60872-3, — Maritime navigation and radiocommunication equipment and systems – Radar
plotting aids – Part 3: Electronic plotting aids (EPA) – Methods of testing and required test
1)
results
IEC 60936-1, — Maritime navigation and radiocommunication equipment and systems – Radar
1)
– Part 1: Shipborne radar – Methods of testing and required test results
IEC 60936-2, — Maritime navigation and radiocommunication equipment and systems – Radar
– Part 2: Shipborne radar for high speed craft (HSC) – Methods of testing and required test
1)
results
IEC 60945:1996, Maritime navigation and radiocommunication equipment and systems –
General requirements, methods of testing and required test results
___________
1)
To be published.
60872-1 © IEC:1998(E) – 5 –
IEC 61162: (all parts), Maritime navigation and radiocommunication equipment and systems –

Digital interfaces
ISO 9000:1987, Quality management and quality assurance standards

IMO Resolution A.477:1981, Performance standards for radar equipment

IMO Resolution A.694:1991, General requirements for shipborne radio equipment forming part

of the global maritime distress and safety system and for electronic navigational aids

IMO Resolution A.820:1995, Performance standards for navigational radar equipment for high-

speed craft
IMO Resolution A.823:1995, Performance standards for automatic radar plotting aids (ARPAs)
IMO Resolution A.824:1995, Performance standards for devices to indicate speed and distance
IMO MSC.64 (67) :1996, Annex 4 – Performance standards for radar equipment
IHO S-52:1996, Specifications for chart content and display aspects of ECDIS
3 Performance requirements
3.1 (A.823/A.1) Introduction
(A.823/A.1.1) Automatic radar plotting aids (ARPA) shall, in order to improve the
3.1.1
standard of collision avoidance at sea:
.1 reduce the workload of observers by enabling them to obtain information about
automatically plotted targets so that they can perform as well with several separate targets
as they can by manually plotting a single target;
.2 provide continuous, accurate and rapid situation evaluation.
3.1.2 (A.823/A.1.2) The radar facilities provided by an ARPA display shall comply with the
performance standards for radar equipment (Resolution A.477) appropriate to its mode of use.
3.1.3 (A.823/A.1.3) In addition to the general requirements contained in resolution A.694,
ARPA shall comply with the following minimum performance standards.

3.1.4 Where an ARPA display is intended for use as the master display of a complete radar
system, the system shall comply with IEC 60936-1. For high speed craft (HSC) ARPA, the
relevant clauses of IEC 60936-2 apply.
3.1.5 Where an ARPA display is intended for use as a slave display of a complete radar
system, it shall comply with the relevant clauses of IEC 60936-1, where applicable to such a
display. For high speed craft (HSC) ARPA, the relevant clauses of IEC 60936-2 apply.
3.1.6 Quality assurance
The ARPA shall be designed, produced and documented by companies complying with
ISO 9000, as applicable.
– 6 – 60872-1 © IEC:1998(E)
3.2 (A.823/A.2) Definitions
Definitions of terms used in these performance standards are given in annex A.

3.3 (A.823/A.3) Performance standards

3.3.1 (A.823/A.3.1) Detection

Where a separate facility is provided for detection of targets, other than by the radar observer,

it shall have a performance not inferior to that which could be obtained by the use of the radar

display.
3 3.2 (A.823/A.3.2) Acquisition
3.3.2.1 (A.823/A.3.2.1) Target acquisition may be manual or automatic for relative speeds
up to 100 knots. However there shall always be a facility to provide for manual acquisition with
the relevant symbol (see symbol 1 of annex E) and cancellation: ARPAs with automatic
acquisition shall 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 shall be defined
and indicated on the display with the relevant symbol (see symbol 2 of annex E).
3.3.2.2 (A.823/A.3.2.2) Automatic or manual acquisition shall have a performance not
inferior to that which could be obtained by the user of the radar display.
3.3.3 (A.823/A.3.3) Tracking
3.3.3.1 (A.823/A.3.3.1) The ARPA shall be able to automatically track, process, simulta-
neously display and continuously update the information on at least 20 targets, whether
automatically or manually acquired. A target being acquired and tracked during the initial stage
shall be shown by a symbol (see symbol 3 of annex E) within 3 s. Targets being tracked when
tracking is in steady state shall be shown by symbols 4A or 4B and 5 of annex E within
20 scans.
3.3.3.2 (A.823/A.3.3.2) If automatic acquisition is provided, description of the criteria of
selection of targets for tracking shall be provided to the user. If the ARPA does not track all
targets visible on the display, targets which are being tracked shall be clearly indicated with the
relevant symbol (see symbols 4A, 4B, or 14 of annex E) on the display. The reliability of
tracking shall not be less than that obtainable using manual recordings of successive target
positions obtained from the radar display.

3.3.3.3 In order to reduce the complexity of vectors and graphics, a facility for the input of
operator interest limits may be provided. If targets are being tracked, which do not require
vectors or graphics, because they are outside the operator interest limits (e.g. range, CPA,
TCPA), they shall be clearly indicated with the relevant symbol (see symbol 14 of annex E).
The operating manual shall contain an explanation of the operator interest limits.
3.3.3.4 (A.823/A.3.3.3) The ARPA shall continue to track an acquired target which is clearly
distinguishable on the display for any 5 out of 10 consecutive scans, provided the target is not
subject to target swop.
3.3.3.5 (A.823/A.3.3.4) The possibility of tracking errors, including target swop, shall be
minimised by ARPA design. A qualitative description of the effects of error sources on the
automatic tracking and corresponding errors shall 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 emissions. Such descriptions shall be in the operating manual.

60872-1 © IEC:1998(E) – 7 –
3.3.3.6 Automatically applied "target identities" shall not be re-used until, as a minimum, the

number assigned equals the maximum number of tracked targets.

3.3.3.7 The ARPA shall continuously track a manoeuvring target.

3.3.3.8 (A.823/A.3.3.5) The ARPA shall be able to display on request with the relevant

symbol (see symbol 6 of annex E) at least four equally time-spaced past positions of any

targets being tracked over a period appropriate to the range scale in use. At least on 3, 6 and

12 nautical mile range scales, user-selectable time intervals of 0,5 min, 1,0 min and 2,0 min

shall be provided. Facility to switch to other time intervals is permitted. The time scale of the

past position plot shall be continuously indicated, together with an indication of whether they

are true or relative "past positions". The operating manual shall contain an explanation of what
the past position plots represent.
3.3.4 (A.823/A.3.4) Display
3.3.4.1 (A.823/A.3.4.1) The display may be a separate or integral part of the ship's radar.
However, the ARPA display shall include all the data required to be provided by a radar display
in accordance with the performance standards for navigational radar equipment.
3.3.4.2 (A.823/A.3.4.2) The design shall be such that any malfunction of ARPA parts
producing data additional to information to be produced by the radar as required by the
performance standards for navigational equipment shall not affect the integrity of the basic
radar presentation.
The equipment shall be regarded as complying with the above if the design is such that, where
practicable, normal performance of the radar system, in accordance with IEC 60936-1, will not
be affected by malfunction of any ARPA subsystem that is not an essential part of the radar.
3.3.4.3 (A.823/A.3.4.3) The ARPA facilities shall be available on at least 3, 6 and 12 mile
range scales, and there shall be a positive indication of the range scale in use.
3.3.4.4 (A.823/A.3.4.4) ARPA facilities may also be provided on other range scales
permitted by resolution A.820 and MSC.64(67), annex 4 and, if provided, shall comply with this
standard.
3.3.4.5 (A.823/A.3.4.5) The ARPA shall be capable of operating with a relative motion
display with "north-up" and "course-up" azimuth stabilisation. In addition, the ARPA may also
provide for a true motion display. If true motion is provided, the operator shall be able to select
for his display either true or relative motion. There shall be a positive indication of the display
mode and orientation in use.
3.3.4.6 (A.823/A.3.4.6) The course and speed information generated by the ARPA for
acquired targets shall be displayed in a vector or graphic form which clearly indicates the
target's predicted motion with the relevant symbols (see symbols 4A or 4B or 5 of annex E). In
this regard:
.1 ARPA presenting predicted information in vector form only shall have the option of both true
and relative vectors. There shall be an indication of the vector mode selected and if true
vector mode is selected, the display shall show whether it is sea or ground stabilized;
.2 an ARPA which is capable of presenting target course and speed information in graphic
form shall also, on request provide the target's true and/or relative vector;
.3 vectors displayed shall be time-adjustable;
.4 a positive indication of the time-scale of the vector in use shall be given; and

– 8 – 60872-1 © IEC:1998(E)
.5 if stationary targets are being used for ground referencing then this shall be indicated with

the relevant symbols (see symbol 13 of annex E). In this mode, relative vectors including

those of the targets used for ground referencing shall be displayed when requested.

3.3.4.7 (A.823/A.3.4.7) The ARPA information shall not obscure the visibility of radar

targets. The display of ARPA data shall be under the control of the radar observer. It shall be
possible to cancel the display of unwanted ARPA data within 3 s of command.

3.3.4.8 (A.823/A.3.4.8) Means shall be provided to adjust independently the brilliance of the
ARPA data and radar data, including complete extinction of the ARPA data.

3.3.4.9 (A.823/A.3.4.9) The method of presentation shall 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 look-out. Facilities to adjust the brightness shall be provided.
3.3.4.10 (A.823/A.3.4.10) Provisions shall be made to obtain quickly the range and bearing
of any object which appears on the ARPA display. The accuracy for this data shall be as stated
in IMO MSC.64(67), annex 4.
3.3.4.11 (A.823/A.3.4.11) 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 shall present in a period
of not more than one minute an indication of the target's motion trend, and display within 3 min
the target’s predicted motion in accordance with 3.3.4.6, 3.3.6, 3.3.8.2 and 3.3.8.3.
3.3.4.12 (A.823/A.3.4.12) After changing range scales on which the ARPA facilities are
available or on resetting the display, full plotting information shall be displayed within a period
of time not exceeding one scan of 360°.
3.3.5 (A.823/A.3.5) Operational warnings
3.3.5.1 (A.823/A.3.5.1) The ARPA shall have the capability to warn the observer with a
visual and audible signal of any distinguishable target which closes to a range or transits a
zone chosen by the observer. The target causing the warning shall be clearly indicated with the
relevant symbols (see annex E) on the display.
A simple guard zone (3.3.5.2) or a combined acquisition and guard zone (3.3.5.4) is required.
3.3.5.2 Guard zone
Where the zone selected is a simple guard zone, a target entering that zone shall initiate an
audible and visual alarm, the visual alarm being symbol 7 of annex E. After acknowledgement
the symbol may cease to flash and shall remain until outside the zone. The area chosen by the
operator shall be narrow (that is of limited range depth) to avoid confusion with symbol 2 of
annex E.
3.3.5.3 Acquisition zone
Where the zone selected is an acquisition zone only (3.3.4.11), without the guard zone
function, a target transiting this zone will be indicated by symbol 3 of annex E, with no audible
alarm. When the tracking criteria has been satisfied, the symbol will change to symbols 4A/B
or 5 of annex E.
60872-1 © IEC:1998(E) – 9 –
3.3.5.4 Combined acquisition and guard zone

Where the zone selected is a combined acquisition and guard zone, a target entering that zone
shall initiate an audible and visual alarm, the visual alarm being symbol 7 of annex E. When
the target is acknowledged, and when the acquisition criteria have been met, this symbol will
change to symbols 3 or 4 of annex E, and the audible alarm shall be suppressed. Any warning

message will be removed. Symbol 5 of annex E may be used instead of symbol 4 of annex E. If

the target was acquired prior to entering a zone, symbols 4 or 5 of annex E shall be shown in

addition to the warning symbol 7 of annex E.

3.3.5.5 The methods of operation which are provided shall be clearly described in the

manufacturer’s operation manual.
3.3.5.6 (A.823/A.3.5.2) The ARPA shall have the capability to warn the observer with a
visual and audible signal of any tracked target which is predicted to close within a minimum
range and time chosen by the observer. The target causing the warning shall be clearly
indicated with the relevant symbols (see symbol 8 of annex E) on the display.
3.3.5.7 (A.823/A.3.5.3) The ARPA shall clearly indicate if a tracked target is lost, other than
out of range, and the target's last tracked position shall be clearly indicated on the display (see
symbol 9 of annex E).
3.3.5.8 (A.823/A.3.5.4) It shall be possible for the observer to activate or de-activate the
audible warning signal.
3.3.6 (A.823/A.3.6) Alpha-numeric data requirements
3.3.6.1 (A.823/A.3.6.1) The observer shall be able to select any tracked target to obtain
data. Targets selected shall be marked with the relevant symbol (see symbol 12 of annex E) on
the radar display. If data is required for more than one target at the same time each symbol
shall be separately identified, for example with a number adjacent to the symbol.
3.3.6.2 (A.823/A.3.6.2) The following data for each selected target shall be clearly and
unambiguously identified and displayed immediately and simultaneously in alpha-numeric form
outside the radar area:
.1 present range of 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); if the CPA has passed, it shall be indicated by a TCPA with

a negative (–) sign;
.5 calculated true course of the target;
.6 calculated true speed of the target.
3.3.6.3 (A.823/A.3.6.3) The display of 3.3.6.2.5 and 3.3.6.2.6 shall include an identification
of whether the data provided is referenced to sea or ground stabilization.
3.3.6.4 (A.823/A.3.6.4) When data for several targets is displayed, not less than two items
shall be displayed simultaneously for each target selected. If the items of data are displayed in
pairs for each target, the groupings shall be 3.3.6.2.1 with 3.3.6.2.2; 3.3.6.2.3 with 3.3.6.2.4;
and 3.3.6.2.5 with 3.3.6.2.6.
– 10 – 60872-1 © IEC:1998(E)
3.3.7 (A.823/A.3.7) Trial manoeuvre

3.3.7.1 (A.823/A.3.7.1) The ARPA shall be capable of graphically simulating the effect on all

tracked targets of an own ship manoeuvre with, or without, time delay before manoeuvre,
without interrupting the updating of target tracking and display of actual target alpha-numeric
data. The simulation mode shall be indicated with the relevant symbol (see symbol 10 of

annex E) on the display.
3.3.7.2 (A.823/A.3.7.2) The operating manual shall contain an explanation of the principles

underlying the trial manoeuvre technique adopted including, if provided, the simulation of own

ship's manoeuvring characteristics.

3.3.7.3 (A.823/A.3.7.3) It shall be possible to cancel a trial manoeuvre at anytime.
3.3.8 (A.823/A.3.8) Accuracy
3.3.8.1 (A.823/A.3.8.1) The ARPA shall provide accuracies not less than those given
in 3.3.8.2 and 3.3.8.3 for the four scenarios defined in appendix 2 (annex B). With the sensor
errors specified in appendix 3 (annex C), the values given relate to the best possible manual
plotting performance under environmental conditions of �10 degrees of roll.
3.3.8.2 (A.823/A.3.8.2) An ARPA shall present within one minute of steady state tracking the
relative motion trend of a target with the following accuracy values (95 % probability values).
Data Relative course Relative speed CPA
(degrees) (knots) (nautical miles)
Scenario
111 2,8 1,6
2 7 0,6 -------
314 2,2 1,8
415 1,5 2,0
NOTE 1 – In steady state tracking both own and target ship follow straight line course at constant speed.
NOTE 2 – Probability values are the same as confidence levels.
NOTE – In the above table, the values are plus (+) and minus (–).
3.3.8.3 (A.823/A.3.8.3) An ARPA shall present within 3 min of steady state tracking the

motion of a target with the following accuracy values (95 % probability values).
Data Relative Relative CPA TCPA True course True speed
course speed
(nautical
Scenario (degrees) (knots) miles) (min) (degrees) (knots)
1 3,0 0,8 0,5 1,0 7,4 1,2
2 2,3 0,3 --- --- 2,8 0,8
3 4,4 0,9 0,7 1,0 3,3 1,0
4 4,6 0,8 0,7 1,0 2,6 1,2
NOTE – In the above table, the values are plus (+) and minus (–).

60872-1 © IEC:1998(E) – 11 –
3.3.8.4 (A.823/A.3.8.4) When a tracked target, or own ship, has completed a manoeuvre,
the system shall present in a period of not more than 1 min an indication of the target's motion
trend, and display within 3 min the target's predicted motion, in accordance with 3.3.4.6, 3.3.6,

3.3.8.2 and 3.3.8.3. In this context, a "manoeuvre of own ship” shall be deemed to consist of an

alteration of course of ±45° in 1 min.

3.3.8.5 (A.823/A.3.8.5) The ARPA shall be designed in such a manner that under the most

favourable conditions of own ship motion the error contribution from the ARPA shall remain

insignificant compared to the errors associated with the input sensors, for the scenarios of

appendix 2 (annex B).
3.3.9 (A.823/A.3.9) Connections with other equipment
3.3.9.1 (A.823/A.3.9.1) The ARPA shall not degrade the performance of any equipment
providing sensor inputs. The connection of the ARPA to any other equipment shall not degrade
the performance of that equipment. This requirement shall be met whether the ARPA is
operating or not. Additionally the ARPA shall be designed to comply with this requirement
under fault conditions as far as is practicable.
3.3.9.2 (A.823/A.3.9.2) The ARPA shall provide an indication when any input from an
external sensor is absent. The ARPA shall also repeat any alarm or status messages
concerning the quality or source of the input data from its external sensors which may influence
its operation.
3.3.9.3 Information exchange between the ARPA and other equipment shall be in accordance
with IEC 61162. As far as possible, such an interface shall not degrade the ARPA performance
by normal or abnormal behaviour of the interface, nor of the signals on it.
3.3.9.4 If no suitable IEC 61162 interface is available, another appropriate interface may be
used.
3.3.10 (A.823/A.3.10) Performance tests and warnings
3.3.10.1 (A.823/A.3.10.1) The ARPA shall provide suitable warnings of ARPA malfunction to
enable the observer to monitor the proper operation of the system. Additionally, test
programmes shall be available so that the overall performance of ARPA can be assessed
periodically against a known solution. When a test programme is being executed the relevant
test symbols (see symbols 11A or B of annex E) shall be displayed.
3.3.10.2 The test scenario may be shown on a synthetic or live picture. For a synthetic picture
symbol 11A of annex E shall be used, and for a live picture symbol 11B of annex E shall be
used.
3.3.11 (A.823/A.3.11) Sea and ground stabilisation
3.3.11.1 (A.823/A.3.11.1) The ARPA shall be capable of sea and ground stabilisation.
3.3.11.2 (A.823/A.3.11.2) Log and speed indicators providing inputs to ARPA equipment
shall be capable of providing the ship's speed through the water in the fore and aft direction.
3.3.11.3 (A.823/A.3.11.3) The ground stabilized input may be provided from the log (dual
axis), or from an electronic position-fixing system, if the speed measurement accuracy is in
accordance with the requirements of resolution A.824 or from tracked stationary targets.
3.3.11.4 (A.823/A.3.11.4) The type of input and stabilisation in use shall be displayed.

– 12 – 60872-1 © IEC:1998(E)
4 Methods of testing and required test results

4.1 General
Tests shall be conducted normally by operating the ARPA under test covering the adjacent sea

area and using simulated target echoes from a synthetic target generator (see annex D) whose

characteristics are similar to target echoes produced by the radar. Means shall be provided for

setting the effective amplitude of one or more simulated targets to 10 dB above peak noise

level, such a target being referred to in the test data as a test reference target.

Unless otherwise stated, simulated targets shall follow constant courses at constant speeds

and tests shall be carried out on each range scale on which ARPA facilities are provided.
Annex D shall be consulted for more details on using simulated targets.
Before these tests the equipment under test (EUT) shall be subjected to, and satisfy, the
relevant parts of IEC 60945.
4.2 (3.3.1, 3.3.2, 3.3.3) Detection, acquisition, tracking and general facilities
4.2.1 Confidence
Before implementing these tests the test operator shall carry out a confidence check, by non-
quantitative means, to ensure that the basic functions of 3.3.1, 3.3.2 and 3.3.3 are available.
4.2.2 (3.3.1) Detection
There is no additional test for this function, as necessary items are covered by other tests.
4.2.3 (3.3.2.1) Manual acquisition
4.2.3.1 Method of measurement
Twenty simulated radar targets superimposed on radar receiver generated noise, or equivalent,
shall be fed into the ARPA. One or more of these targets shall be a reference target. The
targets shall be positioned with an approximately uniform distribution at ranges between one
nautical mile and the maximum of the range scale in use or the maximum acquisition range
provided, and over an arc of not less than 120°.
Two or more of the simulated targets shall have a speed relative to the test radar of not less
than 5 knots and one of these shall start at a range of approximately 5 nautical miles with a
relative speed of 100 knots. The operation of the manual acquisition and tracking cancellation

controls shall be tested on all range scales on which acquisition facilities are provided, and the
target symbols of those acquired, shall be observed on the display.
Acquisition shall be tested in the following cases:
a) each of a pair of targets on the same bearing, at a mean range of approximately 10 nautical
miles, and separated by 0,5 nautical miles;
b) as a) but at a mean range of approximately 2,5 nautical miles;
c) each of a pair of targets at a common range of approximately 10 nautical miles and on
bearings such that the adjacent edges of their targets are separated by 4°;
d) as c) but at a common range of approximately 2,5 nautical miles.

60872-1 © IEC:1998(E) – 13 –
4.2.4 (3.3.2) Automatic acquisition

4.2.4.1 Method of measurement
Where automatic acquisition is provided, the entire procedure of 4.2.3 shall be repeated. The
operation of the automatic acquisition facility shall be checked by a suitable method. For
example, the zone(s) of automatic acquisition shall be set to encompass the minimum possible

area, and shall then be altered in size and/or position to permit successive automatic

acquisition of targets.
4.2.5 (3.3.3) Tracking
4.2.5.1 Method of measurement
Following the acquisition phases of 4.2.3 (and of 4.2.4 if appropriate), the system shall be
required to continue to track the acquired targets for a period of not less than 12 min or until
they exceed the maximum tracking range, or fall below the reference target level.
At the end of the 12 min period the range scale shall be changed and the presentation of full
plotting information shall be checked for those acquired targets which shall be displayed on the
new range scale.
4.2.6 Results required (4.2.3/4.2.4/4.2.5)
.1 It shall be possible in all cases specified in 4.2.3 (4.2.4 if appropriate) to acquire each
target:
a) within five scans after the initiation of acquisition, i.e., from the time of the completion of
the manual acquisition procedure, or
b) in the case of automatic acquisition, the target first entering or appearing within the
acquisition zone.
.2 In all cases, it shall be possible to acquire not less than 20 targets by manual means.
.3 In all cases, a clearly identifiable relevant symbol (see annex E) shall appear on the
display at each acquired target.
.4 It shall be possible, by suitable means provided, including manual means, to cancel any
chosen acquired target.
Immediate automatic re-acquisition is permissible inside, but not outside, any automatic
acquisition zone set by the operator.
.5 The boundary limits of every acquisition zone in use within the range scale in use shall be
indicated clearly on the display with the appropriate symbol in annex E.
.6 Within 20 scans of the initiation of acquisition of each target the appropriate symbol in

annex E shall indicate the general trend of the target motion.
.7 Within 60 scans of the initiation of acquisition, data as required by 3.3.4.6 and 3.3.6.2 shall
be available on all tracked targets.
.8 All symbols shall correlate with the relevant targets unambiguously.
.9 For all tracked targets, the display of past history positions shall be available as required in
3.3.3.8.
.10 The provision of suitable means of complying with 3.3.4.7 and 3.3.4.8 shall be verified.
.11 Compliance with 3.3.4.12 shall be verified.

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4.3 (3.3.3) Tracking reliability

4.3.1 (3.3.3.3) Fading target

4.3.1.1 Method of measurement
The echo due to a test reference target with a relative speed of 20 knots and on a constant

course shall be fed into the ARPA and shall be acquired. To avoid the possibility of target

swop, no other target shall come within 1 nautical mile of the test target.

Starting not less than 60 scans after the initiation of acquisition, the echo shall be caused to

miss 50 % of any 10 consecutive paints in various patterns which shall include missing

alternate paints and missing five consecutive paints. The test shall be repeated with test
reference target relative speeds of five knots and 100 knots.
4.3.2 (3.3.5.7) Lost target warning
4.3.2.1 Method of measurement
At the conclusion of each test of 4.3.1 the test reference target echo shall be suppressed at its
source.
4.3.3 (3.3.3.7) Target manoeuvre
4.3.3.1 Method of measurement
The echo due to a test reference target with a relative speed of 20 knots and on a collision
course with own ship shall be fed into the ARPA and be acquired at a range of not less than 5
nautical miles. When the target reaches a range of 3 nautical miles, it shall be caused to turn
to starboard at a rate 5°/s through an angle of 90° and shall then follow a constant course at
constant speed for not less than 3 min.
4.3.4 (3.3.3.4) Target swop
4.3.4.1 Method of measurement
The echo due to a test reference target with a relative speed of 20 knots and on a collision
course with own ship shall be fed into the ARPA and shall be acquired at a range of
≥10 nautical miles.
When the target reaches a range of 5 nautical miles it shall be caused to pass an unacquired,
stationary, reference target displaced in bearing such that the adjacent edges of their echoes
are separated by 4° and shall continue on the same course for not less than 1 min.

4.3.5 Results required (4.3.1/4.3.2/4.3.3/4.3.4)
.1 The ARPA shall continue to track the test reference target throughout the test of 4.3.1 and
shall not initiate the lost target warning.
.2 The lost target warning shall be initiated automatically not more than 20 scans after the
start of test of 4.3.2. Observe that the indication appears initially at the track position at
which the alarm was initiated.
.3 The ARPA shall continue to track the target throughout the test of 4.3.3.
.4 The ARPA shall continue to track the acquired target throughout the test of 4.3.4.
4.3.6 (3.3.3.8) Past positions
By inspection of the equipment and the manufacturer’s operator’s manual.

60872-1 © IEC:1998(E) – 15 –
4.4 (3.3.8) Tracking accuracy

4.4.1 Method of measurement
.1 The ARPA shall be set to the 12 nautical mile range scale and shall be fed with compass

and log inputs corresponding to scenario 1 of annex B. A test reference target, whose
course, speed and initial position are such that 3 min after acquisition they shall correspond
to those given in scenario 1 of annex B shall be fed into the ARPA. The target echo signal

and own ship inputs shall be generated by means which take account of the sensor errors

listed in annex C including those due to own ship roll of ±10°. The target shall be acquired

and the time of acquisition, t , as defined in 4.2.6.1 shall be noted.
At t + 1 min the motion trend of the target as indicated on the ARPA display in vector or

graphic form shall be observed.
At t + 3 min the true course and speed and the CPA and TCPA of the tracked test target

shall be obtained from the ARPA alpha-numeric readout facility and recorded, and the
motion of the target as indicated on the ARPA display in vector or graphic form shall be
observed. The target echo generator shall be reset and the test repeated until a total of 20
tests have been recorded. If the target echo generator utilises pseudo-random number
generators then it shall be arranged that a different sequence is used for each test.
.2 The observed indications in vector or graphic form shall be compared with the requirements
of 3.3.8.2 or 3.3.8.3 as appropriate.
.3 The error in each recorded value shall be determined by subtracting from it the correct
value for that parameter as derived from this scenario.
.4 The above test procedure shall be repeated successively for scenarios 2, 3 and 4 of
annex B.
.5 The operating manual shall be checked for the inclusion of information relating to the
requirements of 3.3.3.2 and 3.3.3.5.
4.4.2 Results required
If the results of all 20 tests are within the limits given in the tables of 3.3.8.2 or 3.3.8.3 as
appropriate, the equipment shall be considered as complying with the requirements for the
particular scenario under test.
If the result of any test is outside the limits, a statistical analysis shall be applied to all the
results and, if necessary, additional tests shall be carried out.
4.5 (3.3.5.1-5) Closing target warning
4.5.1 Method of measurement
.1 The echo due to a test reference target with a relative speed of 20 knots and on a collision
course with own ship shall be fed into the ARPA. A zone shall be previously adjusted to be
at a range of 10 nautical miles encompassing the bearing of the target and shall not include
a clutter area. The target shall be initially at a range of not less than 11 nautical miles. The
target shall follow a constant course until it reaches a range of 8 nautical miles. The test
shall be repeated with the zone adjusted to a range of 2,5 nautical miles with initial and final
ranges of the target of approximately 3 nautical miles and 1,5 nautical miles respectively.
.2 The operation of the zone shall be observed for an extended period.
.3 All zones ((3.3.5.2) guard, (3.3.5.3) acquisition, (3.3.5.4) combined) provided shall be
checked.
.4 The operating manual shall be checked for th
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