Since radar was introduced in ships
after world war two plotting devices
have been designed first of a simple
construction still used but as time
progressed much more elaborated and
sophisticated design came on the market
the main object is to reduce the burden
on the radar observer but they also aim
to increase the accuracy which is very
important in all plotting
plotting has two main purposes it can
show us where the date how close to a
point before this will take place
calculated targeting parameter which can
be obtained here only a brief will be
given
it'll errors and correct them if or
minimize their possible error sources
pink
era in bearing it speed ship heading due
to own ship maneuvering Parker is
continue these influence these mediums
highly streams
Oh
if the purpose of your plotting includes
relation about targets heading and speed
the water overground basically
of plotting true and relative both
plotting methods can supply the
information required which method is
selected depends on the Preferences of
the navigator in order to define what
plotting is we may divide the plotting
process into four separate operations
detection recognition of the presence of
a target selection selection of targets
requiring closer observation tracking
the process of observing changes in
target position plotting the whole
process of target detection selection
tracking and calculation of target
parameters
in this radar plotting example a
possible collision situation is
illustrated true and relative motion
plotting I'm is one hour
true and relative motion own ship is
heading north along the coast another
ship is seen on petting 019 @ 10.8 not
relative hundred and fifteen degrees
relative speed for not
marine radars have its port side on
board side aspect is measured from dead
ahead
280 degrees on that aspect appeal see
Gators because it's related to the
visual conception when they cite to ship
therefore calculate is a match wanted
information required from plotting in
addition to cpa and tea
definition of aspect aspect is target's
relative barrister taken from the target
to plan a you use a triangle mark to the
letters wo a known as the plotting
triangle the sides of the triangle
represents courses and distances covered
during the same time period to further
explain the plotting triangle and its
uses both the true and a relative plot
have been illustrated here the plotting
triangle is determined by its own ships
and target ships movements wa movements
during the period
y ou a represents targets relative
movements during the period of
observation
for education and training purposes and
for use on board there is a special plot
spiderweb diagrams of the any piece of
paper can be used makes the plotting
much easier the plotting sheet or
Northup presentation have on the radar
it is advantageous to plot with Norman
plot the bearings direct
be able to gain a good understand about
how own ships called bead change affect
triangle that is how to plan avoidance
presents own ships movement a represents
target show a is the relative movement
course 50 degrees to starting target
relative speed limit of course
own ship has changed course 55 degrees
to port but Teresa's more than fifty
percent
this speed by fifty percent and speed
change