International Journal
on Marine Navigation
and Safety of Sea Transportation
Volume 5
Number 1
March 2011
The International Maritime Organization (IMO) [1]
adopted a “Strategy for the development and
implementation of e-Navigation” (MSC85-report,
Annexes 20 and 21).
In particular, IMO adopted the following defini-
tion of e-Navigation:
“e-Navigation is the harmonized collection, inte-
gration, exchange, presentation and analysis of mari-
time information onboard and ashore by electronic
means to enhance berth to berth navigation and re-
lated services, for safety and security at sea and pro-
tection of the marine environment”.
IMO has stated the driving forces and the conse-
quential goal for their e-Navigation concept as fol-
lows: << There is a clear and compelling need to
equip shipboard users and those ashore responsible
for the safety of shipping with modern, proven tools
that are optimized for good decision making in order
to make maritime navigation and communications
more reliable and user friendly. The overall goal is
to improve safety of navigation and to reduce errors.
However, if current technological advances continue
without proper coordination there is a risk that the
future development of marine navigation systems
will be hampered through a lack of standardization
on board and ashore, incompatibility between ves-
sels and an increased and unnecessary level of com-
plexity >> (IMO MSC 85, Annex 20, §2.1).
e-Navigation is therefore a vision for the integra-
tion of existing and new navigational tools, in a ho-
listic and systematic manner that will enable the
transmission, manipulation and display of naviga-
tional information in electronic format.
The paper is organized as follows. After the pre-
paring for e-Navigation in section 2, the initial e-
Navigation architecture is presented in section 3 fol-
lowed by the usage of radar to validate aids to navi-
gation including the identification of buoys by solid
state VTS / navigation radars in section 4. Conclu-
sion and future trends are reported in section 5 while
references in section 6 will close the paper.
IMO has invited IALA and other international or-
ganizations to participate in its work and provide
relevant input. IALA formed the e-Navigation (e-
NAV) committee for the purpose of developing rec-
ommendations and guidelines on e-Navigation sys-
tems and services. The committee aims to review
and develop related IALA documentation on issues
such as the impact of new radar technology on radar
aids to navigation, future Global Navigation Satellite
System (GNSS) and differential GNSS and the im-
pact of electronic ship-borne navigation aids on aids
e-Navigation and Future Trend in Navigation
F. Amato, M. Fiorini, S. Gallone & G. Golino
SELEX - Sistemi Integrati, Rome, Italy
ABSTRACT: The International Maritime Organization (IMO) adopted the following definition of e-
Navigation: “e-Navigation is the harmonised collection, integration, exchange, presentation and analysis of
maritime information onboard and ashore by electronic means to enhance berth to berth navigation and relat-
ed services, for safety and security at sea and protection of the marine environment”. A pre-requisite for the e-
Navigation is a robust electronic positioning system, possibly with redundancy. A new radar technology
emerged from the last IALA-AISM conference held in Cape Town, March 2010, where almost all the manu-
factures companies involved on navigation surveillance market presented at various state of development-
solid state products for VTS and Aids to Navigation indicating a new trend for this application. The paper
present an overview of the systems for global navigation and new trend for navigation aids. The expected de-
velopments in this field will also be briefly presented.
to navigation systems. The committee also works
with other international organizations to develop the
overall e-navigation concept.
Concerning radars, a clear trend emerged from
the last IALA-AISM conference held in Cape Town,
March 2010, where almost all the manufactures
companies involved on navigation surveillance mar-
ket present at various state of development- solid
state products for VTS and Aids to Navigation
[2][3][4]. The trend of events set the evolution from
the microwave tubes (klystrons and magnetron or
travelling-wave) [5] to the solid state technologies. It
starts from the IMO resolution 192(79) [6] who in-
tend to encourage the development of low power,
cost-effective radars removing (from July 2008) the
requirement for S-band radar to trigger RACONS
(radar beacons). Solid state radar may fulfill these
wishes making use of low-power and digital signal
processing techniques to mitigate clutter display that
are instead associated with high-power magnetron
based radars.
A full comparison magnetron versus solid state
VTS radars is provided in [7] including experimental
result with live data to show clutter filtering and
range discrimination of the solid state LYRA 50 ra-
dar. The advantage of solid state transmitted could
be summarized as long operational life and graceful
degradation, coherent processing, high duty cycle,
multi frequency transmission on a wide band, no
high voltage supply and compact technology.
Regarding GNSS and DGNSS, an overview of
the state of art is reported in [8] where also radio
aids to navigation are mentioned while an innovative
usage of radar to validate aids to navigation (AtoN)
is described later in this paper.
In short, based on the IMO definition, three fun-
damental elements must be in place as pre-requisite
for the e-Navigation. These are:
1 worldwide coverage of navigation areas by Elec-
tronic Navigation Charts (ENC);
2 a robust and possibly redundant electronic posi-
tioning system; and
3 an agreed infrastructure of communications to
link ship and shore but also ship and ship.
In previous sections e-Navigation and its pre-
requisite were presented as a concept but in order to
implement such concept a technical architecture is
needed. It is shown hereafter (Figure 1) where the
shipboard entities, the physical link(s) and the shore-
based entities are included in this representation.
On the left side is represented, for simplicity’s
sake, a single “ship technology environment”. From
the e-Navigation concept’s perspective the relevant
devices within the ship technology environment are
the transceiver station, the data sources and the data
sinks connected to the transceiver station, the Inte-
grated Navigation System (INS) and the Integrated
Bridge System (IBS). The transceiver station is
shown as a single station for simplicity’s sake, alt-
hough there may be several transceiver stations. The
entities which are involved with the specifics of the
link technology are confined by the dotted line.
Figure 1. e-Navigation architecture Source: IALA e-NAV140
The shore-based technical e-Navigation services,
in their totality and by their interactions, provide the
interfaces of the shore-based user applications to the
physical link(s). They also encapsulate their tech-
nology to the whole of the common shore-based e-
Navigation system architecture. Encapsulation, used
as an Object Oriented Programming term is ‘the
process of compartmentalizing the elements of an
abstraction that constitute its structure and behavior;
encapsulation serves to separate the contractual in-
terface of an abstraction and its implementation’.
The encapsulation principle hides the technology’s
sophistication from the shore-based e-Navigation
system as a whole and thus reduces complexity. The
entities which are involved with the specifics of the
link technology are confined by the dotted line.
Amongst other benefits, it allows for parallel work
of the appropriate experts in the particular technolo-
gy of a given physical link, provided the functional
interfaces of the shore-based technical e-Navigation
services are well defined.
For the precise technical structure of the shore-
base technical e-Navigation services, the common
shore-base e-Navigation system architecture is under
development for a future IALA Recommendation.
It is also showed the World Wide Radio Naviga-
tion System (WWRNS), which includes GNSS, be-
ing presented as a system external to the e-
Navigation architecture providing position and time
information. The Universal Maritime Data Model
was also introduced as an abstract representation of
the maritime domain [9].
The use of an additional source of information to
improve AtoN has been suggested by Barker in [10]
where he consider the vessel traffic routing infor-
mation providing by the Automatic Identification
System (AIS) as an improvement in the AtoN as-
sessment. On the contrary the on board radar of ves-
sels travelling around an AtoN device could be used
to assess and to check the position of the
buoys/beacons resulting in an almost real-time veri-
fication of the information provided by the Aids and
consequently alert for maintenance if needed. To
this end, new generation VTS / navigation radars [2]
provide a break-through for the task of target classi-
4.1 Identification of buoys by solid state VTS /
navigation radars
In this section an example of application of the de-
scribed system is shown.
Navigation buoys are often affected by drift or
malfunctioning. A method to detect the presence of
the buoy and the correct position is addressed, and
data are sent to ground base station, in order to veri-
fy the position and the presence of the buoy against
the navigation maps. The method described is used
also for maintenance purpose, in case of failure of
the device (i.e. low battery) and uses just the passive
reflector positioned on the top of the buoy.
Conventional VTS / navigation radars have poor
classification capabilities at long distance due to
their non-coherent receiver and the limited range
resolution. Navigation radars equipped with magne-
trons usually are set for medium-high range, to im-
prove safety in navigation, using medium-long puls-
es (i.e. 30-75 m) with the consequence of very poor
discrimination in range.
New generation solid state radars permits to un-
couple resolution from transmitted pulse length by
using a coherent receiver and long coded pulses.
High range resolution can be preserved by imple-
menting a pulse compression algorithm in the digital
processor. The radar “LYRA 50” for example can
provide a range resolution of 9 m for all ranges up to
24 NM making use of long compressed pulses
shown in figure 2.
Figure 2. Example of digital a compressed pulse with close up.
The long uncompressed pulse has a time length of
30 µs (4.5 km) and an instantaneous bandwidth of
22 MHz. Due to the digital pulse compression the
resulting pulse is severely deformed: it presents one
high peak lasting only 60 ns (9 m) and a series of
much weaker peaks (side lobes) lasting all together
60 µs (9 km); however the side lobes are more than
40 dB lower with respect to the main one and their
contribute to the received signal is usually negligi-
Range profile can be associated to a radar report
and stored for classification purpose by the radar da-
ta processor. Buoys can be considered small object
for a radar having range extension less than 1 m
which produce a narrow peak signal in the radar re-
ceiver, whose width equal to the range resolution.
Small vessels usually generate a broader peak and
sometimes even different discriminated peaks when
the length of the vessel is greater than twice the
An addition contribute to the classification pro-
cess of the target can be derived by analysis of the
amplitude of the echoes. A study on the variation of
the amplitude of the target echo over different scans
has been conducted by the authors using live radar
data (examples are shown see figures 3, 4 and 5).
Figure 3. Example of amplitude distribution from an buoy (live
Figure 4. Example of target echoes amplitude distribution from
a small anchored boat (live data).
Figure 5. Example of target echoes amplitude distribution from
a tanker (live data).
For someone in the short term e-Navigation should
remain a theoretical concept but it is indubitably an
overall concept to which all marine users have to
deal with from now on.
Electronic positioning system is a prerequisite for
the e-Navigation and position fixing using GNSS is
prevailing amongst commercial and leisure users. By
the way radars and traditional Aids to Navigation
(AtoN) will continue to be required, at least for re-
dundancy and/or terrestrial backup to satellite sys-
tems, or in many military scenarios. Co-operation
between complementary systems such as radar and
AtoN should become stronger and stronger to as-
sessing the data and improving reliability for more
informed decisions.
These analysis should be used to improve the fil-
tering and the recognition of buoys, not only based
on the expected position data: the recognition pro-
cess is helpful to distinguish the radar echo of a
buoy from other fixed targets such as ships in stand-
by or outcropping rocks.
Further work may include studies on the range
extension of the radar echoes.
[1] Internationa Maritime Office (IMO) website,
[2] F Amato, M. Fiorini, S. Gallone, G. Golino, “New Solid
State frontier on radar technologies”, Proc. International
IALA-AISM Conference 2010, Cape Town, South Africa,
21-27 March 2010
[3] J C Pedersen “A Next Generation Solid State, Fully Coher-
ent, Frequency Diversity and Time Diversity Radar with
Software Defined Functionality”, Proc. International IALA-
AISM Conference 2010, Cape Town, South Africa, 21-27
March 2010
[4] N Ward, M Bransby “New Technology Radars and the Fu-
ture of Racons”, Proc. International IALA-AISM Confer-
ence 2010, Cape Town, South Africa, 21-27 March 2010
[5] Collin R.E. “Foundations for Microwave Engineering” 2nd
Ed., McGraw-Hill, 1992
[6] IMO MSC79 resolution 192(79) (IMO, 2004)
[7] F Amato, M. Fiorini, S. Gallone, G. Golino, “Fully Solid
State Radar for Vessel Traffic Services”, Proc. International
Radar Symposiums, IRS 2010, Vilnius, Lithuania, 16-18
June 2010
[8] M. Fiorini, “e-Navigation: a Systems Engineering Ap-
proach”, Proc. MAST 2010, 5th Maritime Systems and
Technology conference, palazzo dei congressi, Rome, Italy,
9-11, November 2010
[9] e-NAV 140 “The e-Navigation Architecture the initial
Shore-based Perspective” Ed.1.0, IALA Recommendation,
December 2009
[10] R Barker “AIS Traffic Analysis / The Risk Assessment
Process for Aids to Navigation”, Proc. International IALA-
AISM Conference 2010, Cape Town, South Africa, 21-27
March 2010