485
1 INTRODUCTION
Satellite positioning systems are indispensable in
carrying out basic marine navigation tasks.
Navigationisunderstoodasaprocessofconducting
a vehicle from one point to another in a safe and
effective way in the appropriate physical and
geographical environment (Kopacz, Urbański, 1998;
Czaplewski, Morgaś, Kopacz, 2010; C
zaplewski,
2014). However, these systems are not enough to
solve the problem of accessibility to reliable and
highly accurate information about an object’s
position,inparticularinrelationtonavigationmarks
that are located on land and at sea. This is
particularly important when performing many
navigationtasks as part of special works as well as
submarine navigation tasks. Furthermore, it is not
alwayspossibletopreciselydeterminethepositionof
objects other tha
n vessels when carrying out
hydrographic works by using satellite technology.
Forexample,itisverydifficulttopreciselyposition
navigationmarksatsea.Itisalsonoteasytolocat
e
thepositionofnavigationalhazards,suchaswrecks,
underwater and abovewater rocksas well asother
naturalandartificialobstructionstonavigation.This
isbecauseitisimpossibleformeasurementteamsor
hydrographicsurveyvesselstodirectlyapproachthe
objects whose positions are being determined.
Additionally,itisincrediblyimport
antfortheproper
performanceoftasksatseathattherelativepositions
of vessels be precisely maintained. This is
particularlyimportantfor:
hydrographic survey vessels during bathymetric
measurementsandhydrographicsweepsurveys;
research vessels, for example, during seabed
exploration;
warships during the search for submarines,
minesweeping, or the performa
nce of common
tasksinvolvingtheuseofartilleryandrockets.
Development of the IANS
Chain Using a Satellite
System
K.Czaplewski
GdyniaMaritimeUniversity,Gdynia,Poland
ABSTRACT:Thispa
perpresentsideasforcreatinganddevelopingInteractiveNavigationalStructures(IANS)
byusingsatellitesystems.Thepaperpresentsthepossibilityofadaptingthecontemporarymethodsofrobust
estimation that are used in geodesy for the purpose of performing selected marine navigation tasks. IANS
utilisemodern Mestimation methods.Interactivestructures canassisthumanbeingsincarrying outspecial
ta
sks at sea, for example, in identifying objects at sea and on land without the need to approach them.
Moreover,thesestructurescanalsobeusedintheprocessofnavigationcarriedoutbyunderwatervehiclesor
unmannedwatercraft.Thispaperpresentsthem
athematicalmethodsthatareessentialforcreatingIANS.The
theoreticalassumptionsareillustratedwithanexampleofhowIANScanbeusedwhileperformingatypical
navigationtask.Thepapercloseswithinformationaboutresearchstudieswhichdealwiththepracticalaspects
ofusingthissetofmathematicalmethods.
http://www.transnav.eu
the International Journal
on Marine Navigation
and Safety of Sea Transportation
Volume 8
Number 4
December 2014
DOI:10.12716/1001.08.04.02
486
The abovementioned issues and other similar
problems are of vital significance for maritime
economy and national defence. In order to solve
these problems one must not only use satellite
navigation systems but also terrestrial navigation
(geonavigation).
If geonavigation methods are to be used today,
theymustbe
developedin terms of techniques and
technology as well as the methods of analysing
measurement results. Currently, classical geo
navigation uses procedures that do not meet
accuracy standards. Geonavigation should refer to
thewellestablishedmethodsofmoderngeodesythat
arestillbeingdevelopedinordertobeable
tomeet
these standards. Additionally, it is necessary to
automatecalculationsbecausethiswillallowoneto
implement them in integrated navigation systems.
Such implementation should make it possible to
simultaneouslyusedifferentnavigationsystems(so
called combined systems) while employing new
positioning methods. As for data analysis, one
should use
robust Mestimation methods whichare
newbutwellestablishedtheoreticallyandwhichare
currentlybeingdeveloped.Thisapproachtotheissue
ofdeterminingthepositionsofa movingobjectatsea
andastationaryobjectthatisbeingobservedmakes
itpossibletocreatedynamic, interactivenavigational
structures, which
are dealt with in this paper. The
term ‘Interactive Navigational Structures’ (IANS)
(Czaplewski, 2004) should be understood as the
existing systems of navigation ma rks, the other
stationary objects that are observed and craft
carrying out navigation tasks (also submarine
navigation), which allow one to establish the
coordinates of the remaining
elements of the
structure due to the (geometrical and physical)
interdependencies between them. The fact that the
structureisinteractivemeansthatitcanbeconstantly
alteredbythenavigator(observer).
2 BASICASSUMPTIONS
From a geometric perspective, the Interactive
NavigationalStructureismadeupofasetofpoints
z
j
njZ ,...,1:Z
withknowncoordinates(e.g.

YX ,
) in a known coordinate system as well as
subsets of points that are being determined, i.e.
pi
niP ,...,1:P
and
R
l
nlR ,...,1:R
.
Sets
Z
canbemadeupofvisualnavigationmarks,
elements of radar navigation systems, radio
navigation stations and DGPS (Differential Global
Positioning System) reference stations. Set
P
consists of a vessel’s positions
i
P
at sea that are
being determined or the positions of groups of
vesselsthatcarryoutaparticulartasktogether(e.g.a
hydrographicsweepsurvey).Subset
R
ismadeup
ofpointswhosecoordinatesaredeterminedbasedon
the positions that belong to set
P
, which may
complementset
Z
undercertainconditions.
Letusassumethat,atstage

k ,thereisagiven
set
k
Z whichisinsufficienttodetermineavessel’s
position at stage
1
k . Based on a set of points
k
Z , a vessel’s positions

k
P
are determined, and
thecoordinatesofpoints

k
aredeterminedbased
on these positions. Then, a set of points
 
kkk
RZZ ,
1
is available at stage
1
k ;
thissetcanbesupplementedwithotherelementsof
navigation systems. As for the adopted accuracy
criteria, the IANS chains can take different forms.
GeneralrelationswithinIANSareshowninFigure1.
Figure1.Concept ofthe InteractiveNavigational
Structure’schain(ownwork).
Thesetspresentedabovehavebeenconnectedto
form one observational arrangement, within which
geometricquantitiesaremeasured.
Let us assume that a vessel’s position
i
P
was
determinedbyusingthebearingsanddistancesfrom
point
i
P
totheelementsofset Z ;atthesametime
its position was established by using the DGPS.
Moreover, the bearing and distance between a
vessel’s position and point R belonging to set
R
were measured. For such a measurement
arrangement, we can create IANS’s basic element
(Fig.2).
Figure2.IANS’sbasicelement(ownwork).
487
It is assumed that the interactive character of
navigationalstructuresmakes it possible to transfer
the elements of set
R
to set Z , which requires
creatingaspatialarrangementthatwouldallowone
to control the determinations. The element of IANS
that is presented in Figure 2 does not meet these
requirements. The basic element of the Interactive
Navigational Structure does not ensure reliable
assessmentof theaccuracyoftheposition of points
whosecoordinatesarebeingdetermined,andsucha
structureisnotveryrobusttogrosserrors.Inorder
tosolvetheseproblems,theelementsofIANScanbe
connectedtoform IANS chains. Figure 3 presents a
fragmentofsuchachain.
Figure3.FragmentofanIANSchain(ownwork).
Thenavigationalstructure that is presented here
is not only interactive, but also integrative in
character.Thisisbecauseitcombinesdifferentkinds
of observations from various navigation systems. It
should be assumed that any kinds of connections
between the elements of sets
P
Z ,, will be used
when putting IANS into practice. It is also possible
thatobservationswillbefraughtwithsuchlevelsof
error that they will haveto be rejected orthey will
influencethefinal determinationstoalesser extent.
The methodology for establishing an adjustment
problemforeachof
thestagesofdevelopingIANSas
wellasforusingattenuationtoreducetheinfluence
of gross errors on the final determination is
presentedlaterinthepaper.
3 ADJUSTMENTPROBLEMFORTHEBASIC
ELEMENTOFIANSANDTHESOLUTION
By using functional models which are typical of
geodesy (e.g. Wi
śniewski, 2009; Baran, 1999) and
whichhavebeenadoptedforthepurposeofcreating
InteractiveNavigationalStructures,onecanpresenta
robust and decision adjustment problem (1) for the
basicelementofIANS:
  

iiP Ri
ii
DGPS
DGPS
Pii
i
i
iii ii
DGPS DGPS DGPS
DGPS DGPS
PPP
iii
PP
ii
iii
PR
i
0
PP
221 21
00 0
221
21
00
0
ˆˆ
functional models
ˆ
statistic models
min
XX
X
X
XXX
XX
VAd Ad L
Vd XX
CQP CP
CQP
CP










xx
xxx xx
 

 

 

DGPS DGPS DGPS
PR PR iii
ii ii
PP P
ii i
PR
ii
ii ii
DR DR T T
ii
ˆˆ
Φ,Φ,
,
XX XX
XX X
XX
dd dd VPVV P V
dd





xx x
(1)
As part of the above adjustment problem, these
equivalentcovariancematriceswerepresentedinthe
statistical model:
12
0
~
~
ii
xx
PC
and
12
0
~
~
DGPS
i
P
DGPS
i
P
XX
PC
,where:
iii
i xxx
)PV(xTP ,
~
~
DGPS
i
DGPS
i
DGPS
i
DGPS
i
P
XXX
)PV(XTP ,
~
~
(2)
are equivalent weight matrices that have been
determined based on decision and attenuation
matrices:
))T(V(x)V(xT
xx
ii
ii
T,
~
))T(V(X)V(XT
XX
DGPS
i
DGPS
i
DGPS
i
DGPS
i
PP
T,
~
(3)
where:

n
υtυtυtDiag
i
,...,,
21
)T(V
x
attenuation
function

)(x)(x)(x
i
RZi
ii
Diag TTT ,
decisionfunction
and
i
Z
i
Zi
niiniiZ
ddNNDiag
,1,,1,
,...,,,..., ttttT
)(x
)(
,
)(
1,
)(
,
)(
1,
,...,,,...,
i
ni
i
i
i
ni
i
i
i
R
RRi
dRdRNRNRDiag ttttT )(x
Detailedrulesforcreatingdecisionfunctionsand
attenuation functions are described, for example, in
the papers written by Yang (1994), Yang, Song and
Xu (2002), and Wiśniewski (2002), whereas the
methodologyforcreatingadecisionandattenuation
function (3) is described in detail in Czaplewski’s
paper(2004).Inorder
tosimplifyexpression(1),the
followingdesignationscanbeintroduced:
i
DGPS
i
i
x
X
V
V
V
,



i
i
PR
i
i
2
AA
A
I0
,
i
DGPS
ii
i
o
PP
x
L
L
xx
,

i
i
R
i
P
i
X
X
X
d
d
d
ˆ
ˆ
ˆ
,
DGPS
i
P
i
Diag
i
x
x
CCC
~
,
~
~
,
DGPS
i
P
i
Diag
i
x
x
PPP
~
,
~
~
488
Thus,thefinaladjustmentproblemisexpressedin
thefollowing,classicalform:


i
ii
ii
ii i
21
ioi
DR DR T
iii
ˆ
ˆ
mi mi
XX
X
XX
dd
VAd L
CP
ddVPV



(4)
and the solution is as follows (Baran, 1999;
Wiśniewski,2009):
i
1
TT
iii iii
ˆ
X
dAPAAPL


(5)
Therefore, the matrix of adjusted coordinates
takesthefollowingform:
 
P
ii
i
i
i
Ri
i
o
P
P
o
ii
o
ii
R
R
ˆ
ˆ
ˆˆ
ˆˆ
X
X
X
d
X
X
XXd
X
dX













(6)
with an estimator of the covariance matrix (Yang,
1997):
iii
1
2T 2 21
ˆˆˆ
oiii o o
ˆ
XXX
CAPAQP


(7)
The process of solving the problem which is
expressed as formula (4) has an iterative character.
Thefirst(starting)stepshouldbeimplementedina
classical way, i.e. by using the method of least
squares.
4 DEVELOPINGTHEIANSCHAIN
AsingleelementofIANSonlyallowsoneto
adjusta
given vessel’s position
i
P
. Points belonging to
i
R
can only be determined without supernumerary
observationsatthisstage.ThisiswhytheIANSchain
shouldbedeveloped.Forthepurposeofpresenting
the development of the Interactive Navigational
Structure’s chain, let us assume a navigational
situation in which a vessel has moved to position
1i
P
.Thevessel’snewpositionismeasuredrelative
to navigation marks that belong to set
ZZ
1i
,
measurementsusingtheDGPS toset
ZZ
DGPS
i 1
by
using the DGPS, relative to the previously
determinedpoints
RR
i
andrelativetonew(for
point
1i
P
) points
RR
1i
. Let us also assume
thattheelementsofthevessel’spathvector(i.e.the
course and the distance travelled) are known. The
navigation arrangement which is analysed in this
paperispresentedinthefigurebelow.
Figure4.ThestageofdevelopingIANSatmoment
1
i
Since we assume that also DGPS measurements
aremadeatposition
1i
P
(withtheaimofobtaining
coordinates
DGPS
i
P
1
X
with covariance matrix
DGPS
i
P
DGPS
i
P
o
11
2
XX
QC
),wewillwritethefollowing:

 

DGPS
DGPS
DGPS
i1 i1
i1
DGPS
Pi1i1
i1
i1
i1 i1 P
i1
i1
PP
i1
o
PP
i1 i1
o
PP
ˆ
ˆ
ˆˆ
X
X
X
X
VXX
VdXX
XXd







(8)
The coordinates
i
P
X
of position
i
P
have
already been adjusted and they are represented by
estimator
i
P
i
X
ˆ
with covariance matrix
  
1
ˆ
2
ˆ
2
ˆ
i
i
P
i
i
P
i
i
P
oo
XXX
PQC
inthepresentIANSchain.
However,positions
i
P
and
1i
P
are linked to each
otherthroughtheelementsofavessel’spathvector
aswellasindirectly,i.e.throughpointsbelongingto
i
R
which are common to both elements of IANS.
Given the above, estimator

i
P
i
X
ˆ
is not the final
vectorofthecoordinatesofthepreviousposition
i
P
.
Let us assume that vector

1
ˆ
i
P
i
X
is the final one.
Then, if we treat the previous vector as a pseudo
observation, according to the general principles of
sequentialadjustment,wecanwritethefollowing:



ii
P
i
PP
ii
P
i
iP iP
ii
P
i
i1 i
ˆ
PP
i1 i
ˆ
ii1
oo
ˆ
PP
ˆˆ
ˆˆ
ˆˆ
X
XX
X
XX
X
XXV
Vd d
Xd Xd V



(9)
When navigating a single object, coordinates
1
ˆ
i
P
i
X
donothavemuchpracticalimportanceforthe
currentposition
1i
P
(althoughbasedonthe values
of the vector of adjustments
i
P
X
V
ˆ
one can draw
additional conclusions about the accuracy of
navigation).Theadjustedcoordinatesoftheprevious
position are the result of a joint analysis of all
observations that were available for the current
situation
1i
P
.Observationsmustbeanalysedjointly
so as to obtain the best possible determinations of
currentcoordinatesthatarerepresentedby
1
ˆ
i
P
i
X
.
Vector
1
ˆ
i
R
i
X
of the coordinates of points
i
R
which was obtained at position
i
P
will also be
treated as a pseudoobservation. If we assume that
vector
1
ˆ
i
R
i
X
is a joint representation of the
489
coordinates of position
1i
P
, we can write the
following:



ii
R
i
RP
ii
R
i
iR iR
ii
R
i
i1 i
ˆ
RR
i1 i
ˆ
i1 i
oo
ˆ
RR
ˆˆ
ˆˆ
ˆˆ
X
XX
X
XX
X
XXV
Vd d
Xd Xd V



(10)
By using the determinations related to the goal
function, which were presented in Czaplewski’s
paper(2004),aswellasthefunctionalandstatistical
modelsthatwereformulatedearlier,onecanpropose
the following robust and decision adjustment
problem:
   



i1 i1 P i1 R i R i P i1
i1 i1 i i
DGPS
DGPS
P i1 i1
i1
i1
PP
ii
P
i
RR
ii
R
i
i1 i1 i1
i1 i1 i1 i1 i1 i1
PR R P
i1
0
PP
i1 i
ˆ
i1 i
ˆ
21
0
ˆˆ ˆˆ
ˆ
ˆˆ
ˆˆ
XX XX
X
X
XX
X
XX
X
VAd Ad Ad Ad L
Vd XX
Vdd
Vdd
CP C




 






x x
xx x
  
   


i1
DGPS DGPS DGPS DGPS
i1 i1 i1 i1
ii ii
PP PP
ii ii
ii ii
RR RR
ii ii
i1 i1
i1
21
0
21 21
00
21 21
00
ˆˆ ˆˆ
21 21
00
ˆˆ ˆˆ
DR DR
ˆ
min Φ Φ
X
XX XX
XX XX
XX XX
XX
d
P
CP CP
CP CP
CP CP
dd



 










x
   
i1 DGPS i1 i i1 i i1
DR DR DR DR
PR
ˆˆˆˆ
ΦΦΦΦ
XXXX
dddd



x
(11)
with equivalent covariance matrices
12
0
~
~
PC
which have replaced the original ma
trices
12
0
PC
.Whenweintroducethesedenotations:
i
R
i
P
DGPS
i
i
x
i
X
X
X
V
V
V
V
V
ˆ
ˆ
1
1
1
,
 



000
000
000
2
2
2
11
1
11
i
R
iiii
n
i
P
i
RRP
i
I
I
I
AAAA
A
,


i
X
i
X
DGPS
PP
x
i
i
R
i
P
ii
i
d
d
XX
L
L
ˆ
ˆ
11
1
0
 
i
i
R
i
i
P
DGPS
i
i
xi
Diag
XXX
CCCCC
ˆˆ
1
~
,
~
,
~
,
~
~
1
1
,
 
i
i
R
i
i
P
DGPS
i
i
xi
Diag
XXX
PPPPP
ˆˆ
1
~
,
~
,
~
,
~
~
1
1
wecanwriteproblem(11)inthefollowingform:


i1
i1 i1
i1
i1 i1 X i1
21
i1 o i1
DR DR
ˆ
ˆ
min Φ Φ
X
XX
d
VAd L
CP
dd





(12)
Thisestimatoristhesolutiontotheproblem:
i1
1
TT
i1 i1 i1 i1 i1 i1
ˆ
X
dAPAAPL



(13)
Moreover,
i1
i1
1
2T
ˆˆ
oi1i1i1
ˆˆ
ˆ
X
Xd
CC APA


(14)
and
2T
oi1i1i1
i+1
1
ˆ
VPV

f
(15)
Thenthevectorofalloftheadjustedcoordinates
takesthefollowingform:








P
i1
i1
i1
R
i1 i1
i1
i1
i
Ri
i
i
i
P
i
i1
i1
0
P
P
i1
i1
0
R
R
0
i1 i1
0
i1 i1
R
R
0
i1
i1
P
P
ˆ
ˆ
ˆ
ˆ
ˆˆ
ˆˆ
ˆ
ˆ
X
X
X
X
X
d
X
X
d
X
X
XXd
X
dX
X
X
d



















(16)
5 NUMERICALTEST
Inordertoillustratetheabovetheoreticalanalyses,a
numerical test will be presented. This test will
demonstrate the possibility of utilising IANS while
sailingalongthecoastbyusinggeonavigation. Let
usassumethatavesselismanoeuvringinthewaters
oftheSzczecinLagoonandthenavigatordetermines
the vessel’s position by using the DGPS and
observing navigation ma
rks on shore. The way in
which the vessel manoeuvres is presented in
Figure5.
490
Figure5. The vessel’s manoeuvring path in the waters of
theSzczecin Lagoon (ownwork prepared by using Navi
Sailor4000ECS).
During the test, the vessel’s positions were
determined by using the DGPS

21
, PP and they
were also calculated analytically by utilising
observationsofnavigationmarksonland.
Table1.Vessel’spositionsatseaduringthetest.
_______________________________________________
Vessel’s GeographicGaussKrüger
positions coordinatescoordinates
[] []X[m] Y[m]
_______________________________________________
1
P 5349.56’N01428.14’E 5966784.67465033.79
2
P  5346.67’N01427.47’E5961425.53464255.31
3
P
 5345.33’N01423.13’E5958982.34459467.49
4
P  5347.40’N01421.60’E5962837.07457820.13
_______________________________________________
Thevisua
lnavigationmarksthatwereusedinthe
testarepresentedinTable2.
Table 2. Selected navigation marks in the waters of the
SzczecinLagoon.
_______________________________________________
Fixednavigation Geographiccoordinates[][]
marksGaussKrügercoordinates X[m]Y[m]
_______________________________________________
ChurchinWarnołęka

1
S 5341.8’N 01423.10’E
5952434.41459377.85
Churc
hinNoweWarpno

2
S 5343.50’N01423.10’E
5955587.98459405.13
LeftlightatFairway 5348.40’N01420.30’E
Gateno.1

3
S
5964704.43456409.44
_______________________________________________
Table 3 presents the navigational observations
tha
t were made by observing the navigation marks
listedinTable2.
Table3.Opticalbearingstothelandmarks.
_______________________________________________
Vessel’s LandmarksTruebearings[]
positions
_______________________________________________
3
P
 ChurchinWarnołęka
1
S 181.0
ChurchinNoweWarpno

2
S  245.0
LeftlightatFairwayGateno.1

3
S
332.0
4
P  ChurchinWarnołęka
1
S 171.5
ChurchinNoweWarpno

2
S  257.5
LeftlightatFairwayGateno.1

3
S
323.0
_______________________________________________
Aspartofthistest,thenavigatorhadtodetermine
the coordinates of object T (Fig. 5) apart from
determining the vessel’s positions

i
P
. With this
endinview,theopticalbearingstotheobjectwhich
was being observed were determined, one for each
position.Table4presentsthevaluesofthebearings
thatweremeasured.
Table4.TruebearingstomarkT.
_______________________________________________
Vessel’sposition Truebearing[]
_______________________________________________
1
P 226.2
2
P 300.1
3
P
028.0
4
P 084.5
_______________________________________________
The calculat
ions are presented below. The
navigator determined the vessel’s position at P1 as
well as the first bearing to object T. Then, after
moving to position P2 and changing course, the
navigatordeterminedthevessel’spositionaswellas
another bearing to object T. Next, the navigator
determinedtheapproximatecoordinatesof objectT
(Table 5) by using the coordinates of the vessel’s
positions(P1andP2)aswellastheobservationstha
t
hadbeenmaderelativetotheobject.
Table5. Approximate coordinates of object T that were
determinedatpositionP2.
_______________________________________________
Geographiccoordinatesystem=5347.6’N
=01424.7’E
RectangularcoordinatesystemX=5963178.25
Y=461228.31
_______________________________________________
Thevesselwasoncourse243whenmovingfrom
position P2 to position P3. The distance t
ravelled
betweenthesepositionswas2.9nauticalmiles(5375
m). At position P3 the navigator took bearings to
three navigation marks (Table 3) and to object T
(Table4).Therefore,itbecamepossibletodetermine
the vessel’s position by using the observations tha
t
had been made as well as the first estimate of the
coordinatesofobjectT.
Forthepurposesofthetestthatisdescribedhere,
systems of observation equations are formulated
accordingtothefollowingmodel:





XFXXF
XX
XX
XX
XX
jTPj
TPTT
TPjjjj
TPjjjj
TPjiji
j
jjj
j
j
j
FNRNR
Fdd
FNRKR
FNRNR
,
,
,
,
,
,1,1
,1,1
,,
where:
ji
NR
,
ithbearingtothe nth navigation mark at
position
j
P
jj
KR
,1
vessel’s course between positions
1j
P
and
j
P
jj
d
,1
distancebetweenpositions
1j
P
and
j
P
j
T
NR
bearingtoobjectTatposition
j
P
491
j
j
j
P
P
P
y
x
X
coordinates of the vessel at position
j
T
T
T
y
x
X
coordinatesofobjectT
Later in the paper only the determinations of
adjustmentstotheobservationsthatweremadewill
bepresented,aswellastheestimatedcoordinatesof
thevessel’sandobjectT’spositions.
After formulating the system of observation
equations and the adjustment problem, one should
establish, according to the principles of robust
adjust
ment that were described in the first part of
thispaper,whethertheobservationsthatweremade
are fraught with gross errors, which may influence
theresultsoftheadjustment.Inordertodothis,an
adjustmentcovariancematrixisdetermined:
ii
o
m
VV
QC
2
(17)
where:
4
~
2
n
m
ii
T
i
o
VPV
coefficientofvariance
T
iii
T
iii
i
AAPAAPQ
V
1
1
~~
cofactor ma trix of
thevectorofadjustmentsV
Moreover, the acceptable range of standardised
adjustmentsisdeterminedbasedontheformula:
ii
ivv
vk;k

(18)
Standardised adjustments make it possible to
determine the value of the attenuation function
whichisanelementofthedecisionandattenuation
matrix described by formula (3). The attenuation
function serves the purpose of obtaining an
equivalentweightmatrixfromformula(2).Therange
of acceptable adjustments depends on the adop
ted
confidence level
. Given that adjustments (
i
v
)
assume random values, but in accordance with
normaldistribution,wecanwritethefollowing:


ii
vi v i
2
k
i
i
k
Pk v k Pkv k
v
1
exp dv
2
2

 




(19)
where:

ii
vv
ii
C
standard deviation for the ith
adjustment
i
v
i
i
v
v
standardised adjustment within the
acceptablerange
kkv ,
In navigational pra
ctice, it is assumed that
coefficient
2
k
forconfidencelevel 95,0
.
In this numerical test, analyses were limited to
attenuation function


n
υtυtυtDiag
i
,...,,
21
)T(V
x
,
whereas decision function
)(x)(x)(x
i
RZi
ii
Diag TTT ,
was omitted. For the
purposeof navigation tasks, the Danishattenuation
functionisusedmostoften;itisdescribedindetailin
papers written by Hampel et al.(1986),Wiśniewski
(2009),andCzaplewski(2004). Thisfunction canbe
expressedastheformula:



i
g
i
ii
1
vk,k
for
tv
exp l v k v k, k
for


(20)
Figure6.Danishattenuationfunction.
The attenuation function is used to determine
equivalentweights,inaccordancewiththefollowing
formula:



i
i
g
iii
iii
p
vk,k
for
ptvp
exp l v k p v k, k
for



(21)
The values of parameters l and g are selected
experimentallysothatthenumberofiterationsisnot
too large. It is usually assumed that parameters
01.0
l
and 2
g . In accordance with
assumptions(2)and(3),anequivalentweightmatrix
isconstructed:


iii
11
22
ii
tv p 0 0
0tvp 0
00 tvp
xxx
P T(V )P


(22)
After adopting the range of standardised
adjustments
2;2
i
v
and confidence level
%95
, the following values of standardised
adjustments were obtained at the initial
(identification)stage:
492
1
1
1
v
v
v 6.8136 v
 ,
2
2
2
v
v
v 41.5704 v
 ,
v
v
v
v
8955.0
3
3
3
,
4
4
4
v
v
v 17.3476 v
 ,
v
v
v
v
0979.25
5
5
5
,
v
v
v
v
4231.15
6
6
6
,
Onecaneasilynoticethatalloftheobservations,
except for the third bearing, are fraught with gross
error, which results from the assumed range of
standardisedadjustments

v .Therefore,weused
the procedure of robust adjustment, which is
iterative. In order to simplify the presentation of
results, the tables below show the results of robust
adjustmentforposition
3
P
.
Forthe purposeof theexample thatisdescribed
here, the bearing to the church in Nowe Warpno

2
S wasfraughtwithgrosserror.Thisisconfirmed
by the results presented in Tables 6 and 7. The
bearingwhichwasadoptedforthecalculationsand
which was fraught with error was 245.0, and it
should be 247.0. The robust adjustment process
allowedustoobtain:
1 Estimated
coordinatesofthevessel’sposition:
11.459463
21.5958991
38.4
87.8
49.459467
34.5958982
ˆˆ
333
P
o
PP
X xdX
withanerrorindeterminingtheposition
mM
P
9.43
3
.
2 EstimatedcoordinatesofobjectT’sposition:
43.461228
20.5963178
12.0
05.0
31.461228
25.5963178
ˆˆ
3
2
3
P
T
P
T
P
T
X xdX
withanerrorindeterminingtheposition
mM
P
T
3.17
3
.
The vessel was on course
2.337KR
when
moving from position
3
P
to position
4
P . The
distance between these positions was 2.26 nautical
miles(4182m).At position
4
P the navigator made
observations relative to the same navigation marks
thatwereusedatposition
3
P
(Table3)andtookthe
fourth bearing to object T (Table 4). Like at the
previous position, it is possible to determine the
coordinatesofthevessel’spositionandtoonceagain
adjustthecoordinatesofobjectT’sposition.Asatthe
previous stage, we will now start identifying
observations
thatarefraughtwith gross errors. The
acceptedrangeofstandardisedadjustmentsandthe
confidence level did not change. The values of the
standardised adjustments to observations made at
position
4
P areasfollows:
v
v
v
v
11278.0
1
1
1
,
v
v
v
v
2361.0
2
2
2
,
v
v
v
v
0235.0
3
3
3
,
v
v
v
v
0985.0
4
4
4
,
v
v
v
v
4352.0
5
5
5
,
v
v
v
v
4467.0
6
6
6
,
Table6.Valuesoftheattenuationfunctionforparticularobservationsatposition
3
P
.
__________________________________________________________________________________________________
IterationParametersoftheValuesoftheattenuationfunctionforparticularobservations
Step attenuationfunction
l g

1
vt 
2
vt 
3
vt

4
vt 
5
vt


6
vt
__________________________________________________________________________________________________
10.003 2.010.0091 1111
20.03 2.010.8186 1111
30.12.010.6305 1111
40.82.0111111
__________________________________________________________________________________________________
Table7.Valuesofthestandardisedadjustmentsforobservationsmadeatposition
3
P
.
__________________________________________________________________________________________________
IterationParametersoftheValuesofthestandardisedadjustmentsforparticularobservations
Step attenuationfunction
l g
1
v

2
v

3
v

4
v

5
v

6
v
_
__________________________________________________________________________________________________
10.003 2.00.4380 4.5830 0.2288 0.0026 0.3165 0.2425
20.03 2.00.4236 4.1477 0.2313 0.0452 0.2474 0.2061
30.12.00.3996 3.2949 0.2355 0.1163 0.1319 0.1453
40.82.00.3694 1.6858 0.2407 0.2063 0.0144 0.0686
__________________________________________________________________________________________________
493
As one can see above, all of the adjustments are
within the accepted range
2;2
i
v
. Therefore,
it is not necessary to use the procedure of robust
adjustment and decision and attenuation function
)V(xT
x
i
i
,
~
.Now,thecoordinatesofposition
4
P and
of object T’s position can be determined. The
determinations of adjustments at the last stage of
calculationsinthistestareasfollows:
1 Estimatedcoordinatesofthevessel’sposition:
03.457827
45.5962838
90.6
39.1
13.457820
06.5962837
ˆˆ
444
P
o
PP
X xdX
withanerrorindeterminingtheposition
mM
P
98.24
4
.
2 EstimatedcoordinatesofobjectT’sposition:
38.461228
12.5963180
05.0
92.1
43.461228
20.5963178
ˆˆ
4
3
4
P
T
P
T
P
T
X xdX
withanerrorindeterminingtheposition
mM
P
T
72.16
4
.
6 CONCLUSIONS
Themathematicalmethodsthatare proposedinthis
paper allow one to create Interactive Navigational
Structures(IANS),whichcanbehelpfulinperforming
many typical navigational tasks. IANS can be an
invaluable tool that aids in determining the
coordinatesofawreck’s position when the depth of
watermakesitimpossibleformeasurementteamsto
come close to it (Czaplewski, 2004). Moreover, the
methodology forcreatingand developing IANS was
successfully used in radar navigation as a tool that
made the determinations carried out by artificial
neuralnetworksmoreprecise(CzaplewskiandWąż,
2004).
The development
of IANS can act as a
supplementary, analytical method of determining a
vessel’spositionatsea.Letusassumethatavesselis
movingthroughwaterswherethetypicalnavigation
marks are unavailable, but where one can observe
other stationary objects. At the first stage, the
navigator determines the vessel’s positions
by using
theavailablesystemsofnavigationmarksandatthe
same time makes observations relative to stationary
objects. Observations that are made in accordance
with the principles that are described in this paper
will allow one to determine the coordinates of such
objects and then further use them in
navigation as
alternative navigation marks. It should be
remembered that the quality of determinations will
not be as high as when the coordinates of typical
navigationmarksareused.However,sinceoneneeds
tohavecontinuousinformationaboutthepositionof
one’s vessel when there are no other possibilities of
determining
this position, the proposal presented in
thispaperisaproperalternative.
Currently, the author and his research team are
carrying out studies that focus on the use of
InteractiveNavigationalStructuresintheVTS(Vessel
Traffic Service) system. A vessel traffic controller
usingtheVTSsystemcaneasilyspecify
theposition
ofavesselwhichhasstateditspositionwhilebeingin
watersthatarecoveredbythissystemifthecontroller
has the appropriate software which uses the
mathematical methods of creating and developing
IANS.
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