U.S. patent number RE32,357 [Application Number 06/768,187] was granted by the patent office on 1987-02-17 for moving body track indicator system.
This patent grant is currently assigned to Furuno Electric Co., Ltd.. Invention is credited to Syuji Nagao, Ryoichi Nakai, Kazuo Yamauchi.
United States Patent |
RE32,357 |
Nagao , et al. |
February 17, 1987 |
Moving body track indicator system
Abstract
A moving body track indicating system for displaying the track
of a moving body along with latitude and longitude line markers and
cursors on an indicating device such as a cathode-ray tube. The
displayed pattern can be automatically magnified or reduced and
shifted to a desired position. Cursor markers are displayed
parallel to the latitude and longitude line markers with
identifying symbols displayed along with the cursor markers. A
reference point is automatically readjusted wherein the moving
body, a ship in the preferred embodiment, moves beyond the edge of
the display surface.
Inventors: |
Nagao; Syuji (Hyogo,
JP), Nakai; Ryoichi (Hyogo, JP), Yamauchi;
Kazuo (Hyogo, JP) |
Assignee: |
Furuno Electric Co., Ltd.
(Nagasaki, JP)
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Family
ID: |
26393364 |
Appl.
No.: |
06/768,187 |
Filed: |
August 23, 1985 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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600269 |
Apr 12, 1984 |
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Reissue of: |
142793 |
Apr 22, 1980 |
04400780 |
Aug 23, 1983 |
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Foreign Application Priority Data
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Apr 27, 1979 [JP] |
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54-52716 |
Jun 21, 1979 [JP] |
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54-78973 |
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Current U.S.
Class: |
701/454; 345/636;
340/988; 345/440; 340/995.15; 701/521 |
Current CPC
Class: |
G01C
21/3667 (20130101); G01S 1/047 (20130101) |
Current International
Class: |
G01C
21/22 (20060101); G01C 21/20 (20060101); G01S
1/00 (20060101); G01S 1/04 (20060101); G01S
007/04 () |
Field of
Search: |
;364/443,449,450,452,460,461,521 ;340/731,988,990,995 ;343/450-452
;73/178R |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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49-122930 |
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Nov 1974 |
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JP |
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52-141662 |
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Nov 1977 |
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JP |
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Primary Examiner: Chin; Gary
Attorney, Agent or Firm: Sughrue, Mion, Zinn, Macpeak &
Seas
Parent Case Text
.Iadd.This is a continuation of application Ser. No. 600,269, filed
Apr. 12, 1984 now abandoned which is a reissue of U.S. Pat. No.
4,400,780. .Iaddend.
Claims
What is claimed is:
1. A moving body track indicating system which indicates the track
of a moving body on the indicating surface of an indicator in
response to information supplied from means for measuring the
position of the moving body comprising:
(i) transforming means for producing first and second signals
respectively indicating the longitude and the latitude of the
position of the moving body in response to the information supplied
from said means for measuring the position of the moving body;
(ii) line markers signal generating means for producing signals
corresponding to longitude line and the latitude line markers based
on the first and second signals from said transforming means;
(iii) first storing means for storing signals corresponding to each
of the track of the moving body and the longitude and the latitude
line markers;
(iv) second storing means for storing the first and second signals
from said transforming means;
(v) body position signal generating means for generating signals
corresponding to the position marks of the moving body constituting
the track thereof in response to the first and second signals from
said second storing means;
(vi) writing means for writing the signals produced in response to
signals from said body position signal generating means and from
said line markers signal generating means into said first storing
means;
(vii) indicating means for displaying on said indicating surface
the track of the moving body and the longitude line and the
latitude line markers; and
(viii) controlling means for reading signals from said first
storing means and supplying them to said indicating means.
2. A moving body track indicating system as defined in claim 1
further comprising means for producing control signals in
accordance with the scale of the pattern displayed upon said
indicating surface, said body position signal generating means and
said line markers signal generating means being controlled by said
control signal producing means.
3. A moving body track indicating system as defined in claim 1
wherein said body position signal generating means comprises:
(i) first body position signal generating means for generating said
signals corresponding to the moving body's position in response to
said first signal from said transforming means; and
(ii) second body position signal generating means for generating
said signals corresponding to the moving body's position in
response to said second signal from said transforming means.
4. A moving body track indicating system as defined in claim 1
wherein said line markers signal generating means comprises:
(i) reference point storing means for storing a pair of said first
and second signals from said transforming means;
(ii) first line marker signal generating means for producing said
signals corresponding to the longitude line markers in response to
said first signal; and
(iii) second line marker signal generating means for producing said
signals corresponding to said latitude line markers in response to
said second signal.
5. A moving body track indicating system as defined in claim 3
wherein said first body position signal generating means
comprises:
(i) reference point storing means for storing a pair of said first
and second signals from said storing means;
(ii) subtracting means for performing a subtraction operation
between the first signal from said reference point storing means
and the first signal from said transforming means; and
(iii) means for operationally multiplying the output signals from
said subtracting means by a numerical value determined in
accordance with the scale of the pattern upon said indicating
surface.
6. A moving body track indicating system as defined in claim 3
wherein said second body position signal generating means
comprises:
(i) reference point storing means for storing a pair of said first
and second signals from said storing means;
(ii) subtracting means for performing a subtraction operation
between said second signal from said reference point storing means
and said second signal from said transforming means; and
(iii) means for operationally multiplying the output signals from
said subtracting means by a numerical value determined in
accordance with the scale of the pattern upon said indicating
surface.
7. A moving body track indicating system as defined in claim 4
wherein said first line marker signal generating means
comprises:
(i) longitude line signal generating means for producing the
longitude numerical value of a longitude line marker positioned in
the vicinity of a reference point upon said indicating surface in
response to said first signal from said reference point storing
means;
(ii) means for operationally adding the distance numerical value
between two adjacent longitude line markers upon said indicating
surface and the longitude numerical value from said longitude line
signal generating means; and
(iii) means for operationally multiplying the output signals from
said means for operationally adding by a numerical value determined
in accordance with the scale of the pattern upon said indicating
surface.
8. A moving body tract indicating system as defined in claim 4
wherein said second line marker signal generating means
comprises:
(i) latitude line signal generating means for producing the
latitude numerical value of a latitude line marker positioned in
the vicinity of a reference point upon said indicating surface of
an indicator in response to said second signal from said reference
point storing means;
(ii) means for operationally adding the distance numerical value
between two adjacent latitude line markers upon said indicating
surface and the latitude numerical value from said latitude line
signal generating means; and
(iii) means for operationally multiplying the output signals from
said means for operationally adding by a numerical value determined
in accordance with the scale of the pattern upon said indicating
surface.
9. A moving body track indicating system as defined in any of
claims 5, 6, 7 and 8 wherein the magnitudes of said first and
second signals from the reference point storing means are
separately variable.
10. A moving body track indicating system as defined in any of
claims 5, 6, 7 and 8 wherein said numerical value determined in
accordance with the scale of the pattern upon said indicating
surface is variable.
11. A moving body track indicating system as defined in any of
claims 5, 6, 7 and 8 further comprising:
(i) means for detecting that the body's position has reached the
edge of said indicating surface; and
(ii) means for varying the magnitudes of said first and second
signals from said reference storing means automatically in
accordance with the output signals from said detecting means.
12. A moving body track indicating system which indicates the track
of a moving body on the indicating surface of an indicator in
response to information supplied from means for measuring the
position of the moving body comprising:
(i) transforming means for producing first and second signals
respectively indicating the longitude and the latitude of the
position of the moving body in response to the information supplied
from said means for measuring the position of the moving body;
(ii) line markers signals generating means for producing signals
corresponding to longitude and latitude line markers in response to
the first and second signals from said transforming means;
(iii) cursor line markers signal generating means for producing
signals corresponding to cursor line markers parallel to the
latitude and the longitude line markers;
(iv) first storing means for storing signals corresponding to each
of the track of the moving body, the longitude line and the
latitude line markers, and the cursor line markers;
(v) writing means for writing signals produced in response to
signals from said body position signal generating means, said line
markers signal generating means, and said cursor line markers
signal generating means into said first storing means;
(vi) second storing means for storing the first and second signals
from said transforming means;
(vii) body position signal generating means for producing signals
corresponding to the position marks of the moving body constituting
the track thereof in response to the first and second signals from
said second storing means;
(viii) indicating means for displaying on said indicating surface
the track of the moving body, the longitude and the latitude line
markers, and the cursor line markers, and;
(ix) controlling means for reading signals from said first storing
means and supplying them to said indicating means.
13. A moving body track indicating system comprising:
(i) means for measuring the position of a moving body;
(ii) transforming means for producing first and second signals
respectively indicating the longitude and the latitude of the
position of the moving body in response to information supplied
from said means for measuring the position of a moving body;
(iii) line markers signal generating means for producing said
signals corresponding to the longitude line and latitude line
markers based on said first and second signals from said
transforming means;
(iv) first storing means for storing signals corresponding to each
of the track of the moving body and the longitude and latitude line
markers;
(v) second storing means for storing said first and second signals
from said transforming means;
(vi) body position signal generating means for generating signals
corresponding to the position of the moving body in response to
said first and second signals from said second storing means;
(vii) writing means for writing said signals produced by said body
position signal generating means and from said line markers signal
generating means into said first storing means;
(viii) indicating means for displaying on an indicating surface
thereof the track of the moving body and the longitude line and the
latitude line markers; and
(ix) controlling means for reading signals from said first storing
means and supplying them to said indicating means.
14. A moving body track indicating system comprising:
(i) means for measuring the position of a moving body;
(ii) transforming means for producing first and second signals
respectively indicating the longitude and the latitude of the
position of the moving body in response to information supplied
from said means for measuring the position of a moving body;
(iii) line markers signal generating means for producing signals
corresponding to said longitude and latitude line markers in
response to said first and second signals from said transforming
means;
(iv) cursor line markers signal generating means for producing
signals corresponding to cursor line markers parallel to said
latitude and said longitude line markers;
(v) first storing means for storing signals corresponding to said
position of the moving body, said longitude and latitude line
markers, and said cursor line markers;
(vi) writing means for writing said signals produced by said body
position signal generating means, said line markers signal
generating means, and said cursor line markers signal generating
means directly into said first storing means;
(vii) second storing means for storing said first and second
signals from said transforming means;
(viii) body position signal generating means for producing said
signals corresponding to the position of the moving body in
response to said first and second signals from said second storing
means;
(ix) indicating means for displaying on an indicating surface
thereof the track of the position of the moving body, the longitude
and the latitude line markers, and the cursor line markers; and
(x) controlling means for reading from said first storing means and
supplying said signals to said indicating means.
15. A moving body track indicating system which indicates the track
of a moving body on the indicating surface of an indicator in
response to information supplied from means for measuring the
position of the moving body, comprising:
(i) transforming means for producing first and second signals
respectively indicating the longitude and latitude of the position
of the moving body in response to the information supplied from
said means for measuring the position of the moving body;
(ii) body position signal generating means for producing signals
corresponding to a position mark of the moving body in response to
the first and second signals from said transforming means;
(iii) line markers signal generating means for producing signals
corresponding to longitude line and latitude line markers in
response to the first and second signals from said transforming
means, said line markers signal generating means comprising:
(a) reference point storing means for storing a pair of the first
and second signals from the transforming means;
(b) first line marker signal generating means for producing the
signals corresponding to the longitude line markers in response to
the first signal comprising: (1) longitude line signal generating
means for producing the longitude numerical value of the longitude
line marker in the vicinity of a reference point upon said
indicating surface; (2) means for operationally adding a distance
numerical value between the adjacent longitude line markers upon
said indicating surface and the longitude numerical value from said
longitude line signal generating means; and (3) means for
operationally multiplying the output signals from said means for
operationally adding by a numerical value determined in accordance
with the scale of the pattern upon said indicating surface; (c)
second line maker signal generating means for producing the signals
corresponding to the latitude line markers in response to the
second signal;
(iv) storing means for storing signals corresponding to the
position marks of the moving body constituting the track thereof
and the longitude and latitude line markers;
(v) writing means for writing the signals produced in response to
signals from said body position signal generating means and said
line markers signal generating means into said storing means;
(vi) indicating means for indicating on said indicating surface the
track of the moving body and the longitude line and the latitude
line markers; and
(vii) controlling means for reading signals from said storing means
and supplying them to said indicating means.
16. A moving body track indicating system which indicates the track
of a moving body on the indicating surface of an indicator in
response to information supplied from means for measuring the
position of the moving body, comprising:
(i) transforming means for producing first and second signals
respectively indicating the longitude and latitude of the position
of the moving body in response to the information supplied from the
said means for measuring the position of the moving body;
(ii) body position signal generating means for producing signals
corresponding to a position mark of the moving body in response to
the first and second signals from said transforming means;
(iii) line marker signal generating means for producing signals
corresponding to longitude line and latitude line markers in
response to the first and second signals from said transforming
means, said line markers signal generating means comprising:
(a) reference point storing means for storing a pair of the first
and second signals from the transforming means;
(b) first line markers signal generating means for producing the
signals corresponding to the longitude line markers in response to
the first signal; and
(c) second line markers signal generating means for producing the
signals corresponding to the latitude line markers in response to
the second signal, said second line markers signal generating means
comprising: (1) latitude line signal generating means for producing
the latitude numerical value of sid latitude line maker in the
vicinity of reference point upon said indicating surface; (2) means
for operationally adding the distance numerical value between two
adjacent latitude line markers upon said indicating surface and the
latitude numerical value from said latitude line signal generating
means; and (3) means for operationally multiplying the output
signals from said means for operationally adding by a numerical
value determine in accordance with the scale of the pattern upon
said indicating surface;
(iv) storing means for storing signals corresponding to the
position marks of the moving body constituting the track thereof
and the longitude and latitude line markers;
(v) writing means for writing the signals produced in response to
signals from said body position signal generating means and said
line markers signal generating means into said storing means;
(vi) indicating means for indicating on said indicating surface the
track of the moving body and the longitude line and the latitude
line markers; and
(vii) controlling means for reading signals from said storing means
and supplying them to said indicating means. .Iadd.
17. A moving body track indicating system comprising:
(i) means for measuring the position of a moving body and producing
first and second signals representative of said position;
(ii) line markers signal generating means for producing signals
corresponding to longitude line and latitude line markers based on
said first and second signals from said means for measuring the
position of a moving body;
(iii) first storing means for storing signals corresponding to each
of the track of the moving body and the longitude and latitude line
markers;
(iv) second storing means for storing said first and second signals
from said means for measuring the position of the moving body;
(v) body position signal generating means for generating signals
corresponding to the position of the moving body in response to
said first and second signals from said second storing means;
(vi) writing means for writing said signals produced by said body
position signal generating means and from said line markers signals
generating means into said first storing means;
(vii) indicating means for displaying on an indicating surface
thereof the track of the moving body and the longitude line and the
latitude line markers; and
(viii) controlling means for reading said signals from said first
storing means and supplying them to said indicating means.
.Iaddend. .Iadd.18. A moving body track indicating system
comprising:
(i) means for measuring the position of a moving body and producing
first and second signals representative of said position;
(ii) line markers signal generating means for producing signals
corresponding to longitude line and latitude line markers based on
said first and second signals from said means for measuring the
position of a moving body;
(iii) first storing means for storing signals corresponding to the
track of the moving body;
(iv) second storing means for storing said first and second signals
from said means for measuring the position of the moving body;
(v) body position signal generating means for generating signals
corresponding to the position of the moving body in response to
said first and second signals from said second storing means;
(vi) writing means for writing said signals produced by said body
position signal generating means into said first storing means;
(vii) indicating means for displaying on an indicating surface
thereof the track of the moving body and the longitude line and the
latitude line markers; and
(viii) controlling means for reading said signals from said first
storing
means and supplying them to said indicating means. .Iaddend.
.Iadd.19. A moving body track indicating system comprising:
(i) means for providing first and second signals representative of
a position of a moving body;
(ii) line markers signal generating means for producing signals
corresponding to longitude line and latitude line markers based on
said first and second signals;
(iii) first storing means for storing signals corresponding to each
of the track of the moving body and the longitude and latitude line
markers;
(iv) second storing means for storing said first and second
signals;
(v) body position signal generating means for generating signals
corresponding to the position of the moving body in response to
said first and second signals from said second storing means;
(vi) writing means for writing said signals produced by said body
position signal generating means and from said line markers signals
generating means into said first storing means;
(vii) indicating means for displaying on an indicating surface
thereof the track of the moving body and the longitude line and the
latitude line markers; and
(viii) controlling means for reading said signals from said first
storing
means and supplying them to said indicating means. .Iaddend.
.Iadd.20. A moving body track indicating system comprising:
(i) means for measuring the position of a moving body and producing
first and second signals representative of said position;
(ii) means for providing a pair of first and second reference point
signals related to said position of a moving body;
(iii) line markers signal generating means for producing signals
corresponding to longitude line and latitude line markers based on
said first and second reference point signals;
(iv) first storing means for storing signals corresponding to each
of the track of the moving body and the longitude and latitude line
markers;
(v) second storing means for storing said first and second
signals;
(vi) body position signal generating means for generating signals
corresponding to the position of the moving body based on said
first and second signals from said second storing means and said
first and second reference point signals;
(vii) writing means for writing said signals produced by said body
position signal generating means and from said line markers signals
generating means into said first storing means;
(viii) indicating means for displaying on an indicating surface
thereof the track of the moving body and the longitude line and the
latitude line markers; and
(ix) controlling means for reading said signals from said first
storing means and supplying them to said indicating means.
.Iaddend. .Iadd.21. A moving body track indicating system
comprising:
(i) means for measuring the position of a moving body and producing
first and second signals representative of said position;
(ii) means for generating and storing a pair of first and second
reference point signals;
(iii) line markers signal generating means for producing signals
corresponding to longitude line and latitude line markers based on
said first and second reference point signals from said reference
point storing means;
(iv) first storing means for storing signals corresponding to each
of the track of the moving body and the longitude and latitude line
markers;
(v) second storing means for storing said first and second
signals;
(vi) body position signal generating means for generating signals
corresponding to the position of the moving body based on said
first and second signals from said second storing means and said
first and second reference point signals from said reference point
storing means;
(vii) writing means for writing said signals produced by said body
position signal generating means and from said line markers signals
generating means into said first storing means;
(viii) indicating means for displaying on an indicating surface
thereof the track of the moving body and the longitude line and the
latitude line markers; and
(ix) controlling means for reading said signals from said first
storing
means and supplying them to said indicating means. .Iaddend.
.Iadd.22. A moving body track indicating system comprising:
(i) means for providing first and second signals representative of
a position of a moving body;
(ii) line markers signal generating means for producing signals
corresponding to longitude line and latitude line markers based on
said first and second signals;
(iii) first storing means for storing signals corresponding to the
track of the moving body;
(iv) second storing means for storing said first and second
signals;
(v) body position signal generating means for generating signals
corresponding to the position of the moving body in response to
said first and second signals from said second storing means;
(vi) writing means for writing said signals produced by said body
position signal generating means into said first storing means;
(vii) indicating means for displaying on an indicating surface
thereof the track of the moving body and the longitude line and the
latitude line markers; and
(viii) controlling means for reading said signals from said first
storing means and supplying them to said indicating means.
.Iaddend. .Iadd.23. A moving body track indicating system
comprising:
(i) means for measuring the position of a moving body and producing
first and second signals representative of said position;
(ii) means for providing a pair of first and second reference point
signals related to a position of said moving body;
(iii) line markers signal generating means for producing signals
corresponding to longitude line and latitude line markers based on
said first and second reference point signals;
(iv) first storing means for storing signals corresponding to the
track of the moving body;
(v) second storing means for storing said first and second
signals;
(vi) body position signal generating means for generating signals
corresponding to the position of the moving body based on said
first and second signals from said second storing means and said
first and second reference point signals;
(vii) writing means for writing said signals produced by said body
position signal generating means into said first storing means;
(viii) indicating means for displaying on an indicating surface
thereof the track of the moving body and the longitude line and the
latitude line markers; and
(ix) controlling means for reading said signals from said first
storing means and supplying them to said indicating means.
.Iaddend. .Iadd.24. A moving body track indicating system
comprising:
(i) means for measuring the position of a moving body and producing
first and second signals representative of said position;
(ii) means for generating and storing a pair of first and second
reference point signals;
(iii) line markers signal generating means for producing signals
corresponding to longitude line and latitude line markers based on
said first and second reference point signals from said reference
point storing means;
(iv) first storing means for storing signals corresponding to the
track of the moving body;
(v) second storing means for storing said first and second
signals;
(vi) body position signal generating means for generating signals
corresponding to the position of the moving body based on said
first and second signals from said second storing means and said
first and second reference point signals from said reference point
storing means;
(vii) writing means for writing said signals produced by said body
position signal generating means into said first storing means;
(viii) indicating means for displaying on an indicating surface
thereof the track of the moving body and the longitude line and the
latitude line markers; and
(ix) controlling means for reading said signals from said first
storing means and supplying them to said indicating means.
.Iaddend.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a moving body track indicating
system for indicating on the display surface of an indicator
longitude and latitude line markers as well as the track of a
moving body.
A moving body track indicating system typically includes a
navigation aid apparatus as a Loran receiver, an Omega receiver or
an NNSS (Navy Navigation Satellite System) receiver for measuring
the positions of moving bodies. Such systems utilize the output
signals from the receiver to successively plot the positions of the
moving body in which the system is utilized on an indication medium
such as a recording paper on which longitude and latitude line
markers have been previously printed thereby indicating the track
of the moving body thereon. Such a moving body track indicating
system may be installed on moving bodies such as ships or
airplanes. Hereinafter, the present invention will be described
with reference to a ship track indicating system although, as
explained above, the invention is not limited to that particular
system.
Ship track indicating systems have been proposed and widely used in
which a mechanically operated X-Y recorder successively plots the
positions of a ship on a chart based on positional information
supplied from a navigational aid device thereby tracing the ship's
track on the chart. The X-Y recorder in these systems is operated
in such a way that the recording pen thereof is moved in X and Y
directions through distances determined both by the distance
difference between a reference point and the ship's position and by
the scale of the chart used. In operation, complicated adjustments
must firstly manually be made to establish a reference point on the
chart and to determine the amount of movement of the recording pen
in accordance with the map scale selected. Further, when a
magnified or reduced pattern of the ship's track is desired to be
recorded on the recording paper, the amount of travel of the
recording pen must be manually re-adjusted. The conventional system
has another drawback in that the pattern of the recorded ship's
track together with the longitude and latitude line markers cannot
be shifted to a desired position. If a shift were to be attempted,
the same pattern would simply be reproduced at a different position
on the recording paper even if the reference point is moved to a
proper position. Furthermore, the reference point must be manually
re-adjusted when the position of a ship goes beyond the boundary of
the chart making it necessary to always begin plotting the position
of the ship at an appropriate part of the recording paper.
Accordingly, an object of the invention is to provide a ship track
indicating system which can electronically automatically indicate
on the display surface of an indicator longitude and latitude line
markers as well as a ship's track.
Another object of this invention is to provide a ship track
indicating system which can automatically magnify or reduce the
displayed pattern over the indicating surface of an indicator.
Yet another object of this invention is to provide a ship track
indicating system which can automatically shift the displayed
pattern to any desired position over the indicating surface of an
indicator.
Still another object of this invention is to provide a ship track
indicating system which can indicate movable cursor line markers
which are parallel to the longitude and latitude line markers in
addition to the ship's track with the longitude and latitude line
markers extending over the display surface of an indicator.
A still further object of this invention is to provide a ship track
indicating system which can indicate symbols corresponding to the
cursor line markers parallel to the latitude and longitude line
markers.
Moreover, an object of this invention is to provide a ship track
indicating system which can automatically magnify or reduce the
displayed pattern wherein the ship's track, the longitude and
latitude line markers, and the cursor line markers and/or the
symbols associated therewith are displayed.
A further object of this invention is to provide a a ship's track
indicating system which can automatically shift the displayed
pattern to a desired position wherein the ship's track, the
longitude and latitude line markers, and the cursor line markers
and/or the symbols associated therewith are displayed.
Another object of this invention is to provide a ship track
indicating system which can automatically shift the displayed
pattern to a proper position wherein the ship's track as well as
the longitude and latitude line markers, the cursor line markers
and associated symbols are still indicated when the present
position of a ship goes beyond the display surface of the
indicator.
One more object of this invention is to provide a moving body track
indicating system which can electronically automatically indicate
on the indicating surface of an indicator longitude and latitude
line markers as well as a moving body's track.
SUMMARY OF THE INVENTION
In order to achieve these and other object of the invention, in
accordance with one aspect of the present invention, a moving body
track indicating system is provided which includes (i) indicating
means for indicating on an indicating surface thereof the track of
a moving body and longitude line and latitude line markers, (ii)
storing means for storing electrical signals corresponding to each
of the moving body's track and the longitude and latitude line
markers, (iii) controlling means for reading from the storing means
and supplying the electrical signals to the indicating means, (iv)
first signal generating means for generating the signals
corresponding to the moving body's position in response to
information supplied from means for measuring the position of the
moving body, (v) second signal generating means for generating the
signals corresponding to the longitude and latitude line markers in
response to information supplied from the means for measuring the
position of the moving body, and (vi) writing means for writing
electrical signals produced in response to the signals from the
first and second signal generating means into the storing
means.
Other objects and features of the present invention will be
described in more detail herein with reference to the accompanying
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a graphic representation of the face of a cathode-ray
tube used in a ship track indicating system constructed in
accordance with a preferred embodiment of the present
invention;
FIG. 2 is a general schematic block diagram of a ship track
indicating system constructed in accordance with the preferred
embodiment of the invention;
FIG. 3 is a general schematic block diagram of a ship track
indicating system constructed in accordance with a second
embodiment of the invention;
FIG. 4 is a detailed schematic block diagram of the ship track
indicating system of FIG. 3;
FIG. 5 is a detailed schematic block diagram of the longitude and
latitude line marker indicating section of the ship track
indicating system illustrated in FIG. 4;
FIG. 6 is a detailed schematic block diagram of the ship's position
plotting section of the ship track indicating system illustrated in
FIG. 4;
FIG. 7 is a detailed schematic block diagram combining the diagrams
of FIGS. 5 and 6;
FIG. 8 is a detailed schematic block diagram of the cursor line
markers indicating section of the ship track indicating system
illustrated in FIG. 4;
FIG. 9 is a detailed schematic block diagram of the longitude
signal generator or latitude signal generator of the ship track
indicating system illustrated in FIGS. 4, 5 or 7;
FIG. 10 is a schematic block diagram of the ship position signal
generator of ship track indicating system illustrated in FIGS. 4, 6
or 7;
FIG. 11 is a schematic block diagram of the NV-LL transformer of
the ship track indicating system illustrated in FIGS. 4 or 8;
and
FIG. 12 is a schematic block diagram of an automatic pattern
shifter used with the ship track indicating system according to the
present invention.
Throughout the drawings, the same reference numerals are given to
like components and the same alphabetic reference designations are
given to like signals.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring first to FIG. 1, the plotted track of a ship 1, longitude
line markers 2, latitude line markers 3, cursor line markers 4, and
symbols 5 and 6 which identify by longitude and latitude the
respective cursor line markers are indicated upon the face 7 of a
cathode-ray tube.
Referring to FIG. 2, longitude line markers 2, latitude line
markers 3 and the track of a ship 1 are indicated upon the face 7
of a cathode-ray tube (CRT). A display memory unit 8 stores
electrical signals corresponding to each of the ship's tracks and
the longitude and latitude line markers. A read control circuit 9
appropriately controls the display memory unit 8 and the CRT so
that the electrical signals read from the memory unit 8 produce
bright spots at corresponding places upon the face 7 of the CRT so
as to indicate the ship's track as well as the line markers. A ship
position signal generator 10 generates in response to the
information supplied from a navigational aid device 11 signals
corresponding to the position of the ship indicated upon the face 7
of the CRT. Markers signal generator 12 produces signals
corresponding to the longitude and latitude line markers displayed.
A write control circuit 13 appropriately controls the ship position
signal generator 10, the markers signal generator 12, and the
display memory unit 8 so that the electrical signals corresponding
to the ship's track and the longitude and latitude line markers are
written into corresponding selected locations of the display memory
unit 8. The navigational aid device 11, which may for example
include a Loran receiver, produces the information corresponding to
the instantaneous ship's position.
As shown in the embodiment of FIG. 3, the navigational aid
apparatus 20 may be a Loran C receiver which produces at
predetermined time intervals information relating to the ship's
position and transfers it to a transforming circuit 21. The
transforming circuit 21 produces, in response to the position
information transmitted from the navigational aid device 20,
numerical value signals indicating the longitude and latitude of
the ship's position which are coupled to a line markers signal
generator 14 and a ship position memory unit 34. The line markers
signal generator 14 produces the signals corresponding to the
longitude and latitude line markers which are displayed upon the
face of the CRT. The ship position memory unit 34 passes pairs of
the longitude and latitude numerical value signals to a ship
position signal generator 35 while also successively storing the
pairs of signals therein. The ship position signal generator 35
produces the signals corresponding to the ship's position indicated
upon the face of the CRT. The write control circuit 13
appropriately controls the line markers signal generator 14, the
ship position signal generator 35 and the display memory unit 8 so
that electrical signals corresponding to the ship's track and the
longitude and latitude line markers are written, in response to the
output signals from the signal generators 14 and 35, into proper
locations in the display memory unit 8. The read control circuit 9
controls the display memory unit 8 and the indicator so as to
thereby display the ship's track and the longitude and latitude
line markers upon the face 7 of the CRT.
Referring to FIG. 5, the operation of displaying longitude and
latitude line markers upon the face of the CRT will first be
explained. Longitude line markers 2 and latitude line markers 3 are
both displayed upon the face 7 of the CRT. A scanning circuit 15 is
controlled by a read control circuit 16 to scan the electron beam
of the CRT in both horizontal and vertical directions. The read
control circuit 16 appropriately controls the display memory unit
8, a memory buffer register 17 and the scanning circuit 15 so that
the digital electrical signals read from the display memory unit 8
are transmitted through the memory buffer register 17 to the
intensity modulation input of the CRT so as to thereby display the
longitude and latitude line markers upon the face thereof. The
display memory unit 8 includes, by way of example, m.times.n
semiconductor RAM (random access memory) elements arranged in m
columns and n rows with the number of RAM elements being the same
as that of the picture elements of the screen of the CRT wherein
the picture elements may also be arranged in m columns and n rows.
The display memory unit 8 writes a 1 into the storage location
determined by the address lines supplied from the X- and Y-address
registers 18 and 19 while all other storage elements are maintained
in a 0 state. The display memory unit 8 simultaneously reads out
all the signals in a given row thereof and loads them in parallel
into the memory buffer register 17. The memory buffer register 17,
controlled by the read control circuit 16, serially reads out the
stored signals coupling them to the intensity modulation input of
the cathode-ray tube.
The transforming circuit 21 produces, in response to the ship
position information transmitted from the radio navigational aid
device 20, the numerical value signals indicating the longitude and
latitude of the ship's position which are coupled to up-down
counters 22 and 23. The up-down counters 22 and 23 respectively set
therein the longitude and latitude numerical value signals
corresponding to a reference point, by way of example, fixed at the
center of the face of the CRT. The up-down counter 22 initially
sets therein, by way of example, a first longitude numerical value
signal representative of the ship's position soon after the ship
track indicating system is connected to power mains and thereafter
continuously supplies the signal to a longitudinal signal generator
25. The up-down counter 23 sets therein the first latitude
numerical value signal representative of the ship's position and
continuously supplies the signal to a latitude signal generator 26.
The longitude signal generator 25 produces the numerical value
signals corresponding to the longitude line markers displayed upon
the face of the CRT supplying them to the X-address register 18
through an OR gate 27 and also transmits a driving pulse to a
counter 28 to enable it to successively supply a series of
increasing numerical values to the Y-address register 19 through an
OR gate 29. The X- and Y-address registers 18 and 19 are
respectively provided with m and n elements and corresponding
select address lines of the display memory unit 8 when particular
register elements thereof are identified. Some elements of the
X-address register 18 are fixedly identified by the output signals
from the longitude signal generator 25 and each of the elements of
the Y-address register 19 is successively identified thereby
writing 1's into all the storage elements in the columns selected
by the X-address register 18 and hence storing all the necessary
signals to display the longitude line markers.
The latitude signal generator 26 produces the numerical value
signals respectively corresponding to the latitude line markers
indicated upon the face of the CRT and couples them to the
Y-address register 19 through an OR gate 29. The latitude signal
generator 26 also transmits a driving pulse to a counter 30 to
enable it to successively supply a series of increasing numerical
values to the X-address register 18 through an OR gate 27. In the
same manner as in the case of longitude line markers, some elements
of the Y-address register 19 are fixedly identified by the output
signals from the latitude signal generator 26 and each of the
elements of the X-address register 18 is successively identified
thereby writing 1's into all the storage elements in the rows
selected by the Y-address register 19 and hence storing all the
necessary signals required to display latitude line markers on the
face of the CRT. The construction and operation of the longitude
and latitude signal generators 25 and 26 will be explained later in
further detail.
A magnifying ratio setting unit 31 produces signals utilized for
magnifying or reducing the pattern displayed upon the face of the
CRT to each of the longitude and latitude signal generators 25, 26.
The magnifying ratio setting unit 31 comprises an up-down counter
which produces numerical values to the signal generators 25, 26,
and is controlled by a magnifying ratio selector switch 32 through
an interface unit 33.
When it is desired to magnify or reduce the pattern displayed upon
the face of the CRT, the magnifying ratio selector switch 32 is
depressed to cause the interface unit 33 to transmit a reset pulse
to the display memory unit 8 and to cause the magnifying rate
setting unit 31 to transmit signals to the longitude and latitude
signal generators 25 and 26. The reset pulse first clears all the
electrical digital signals stored in the display memory unit 8. The
longitude and latitude signal generators 25 and 26 then produce the
numerical value signals respectively corresponding to the longitude
and latitude line markers to be displayed at a magnified scale upon
the face of the CRT. Accordingly, the electrical digital signals
corresponding to the longitude and latitude line markers on a
magnified scale are stored in the display memory unit 8 as a result
of which magnified longitude and latitude line markers are plotted
upon the face of the CRT.
Referring to FIG. 6, the operation of plotting the track of a ship
upon the face of the CRT will be explained. The transforming
circuit 21 produces the numerical value signals corresponding to
the longitude and latitude of the ship's position which are coupled
to the up-down counters 22 and 23 and the ship position memory unit
34. The up-down counters 22 and 23 respectively set therein the
longitude and latitude signals of the reference point, which is the
center of the face 7 of the CRT, and continuously supply them to a
ship position signal generator 36. The ship position memory unit
34, which may be constructed of semiconductor RAM elements and is
controlled by a write control circuit 39, passes a pair of the
longitude and latitude numerical value signals to the ship position
signal generator 36 and at the same time stores the signals
representative of the ship's position accumulatively. The write
control circuit 39 comprises a counter which repetitiously performs
an increasing count operation from one to the same number of the
memory elements of the ship position memory unit 34, and produces
counted values to locate the memory elements into which the signals
from the transforming circuit 21 are written. The ship position
signal generator 36 includes longitude and latitude units 37 and
38. The longitude unit 37 produces a numerical value signal
corresponding to positions of the ship displayed upon the face of
the CRT in response to the output signals received from the up-down
counter 22 and the ship position memory unit 34 and couples the
numerical value signal to the X-address register 18. The latitude
unit 38 supplies a numerical value signal corresponding to the
positions of the ship upon the display surface in response to the
output signals received from the up-down counter 23 and the ship
position memory unit 34 and couples that numerical value signal to
the Y-address register 19. The construction and operation of the
longitude and latitude units 37, 38 will be explained in detail
later. The X- and Y-address registers 18 and 19 respectively select
corresponding imaginary address lines corresponding to a selected
location thereby writing a 1 into the selected storage location of
the display memory unit 8.
This operation is repeated every time the output signals from the
ship position memory unit 34 are produced with the result that
corresponding electrical digital signals relating to the ship's
track are stored in the display memory unit 8. The read control
circuit 16 appropriately controls the display memory unit 8, the
memory buffer register 17 and the scanning circuit 15 so that the
ship's track is plotted upon the face of the CRT. The output
signals from the magnifying rate setting unit 31 are supplied to
the ship position signal generator 36.
When it is desired to magnify or reduce the pattern displayed upon
the face of the CRT, the magnifying switch 32 is depressed causing
the interface unit 33 to transmit pulse signals to the display
memory unit 8 and a read control circuit 40. The read control
circuit 40 comprises a counter produces counted values to locate
the memory elements of the ship position memory unit 34 from which
the stored signals are read out. The pulse applied to the display
memory unit 8 first clears all the electrical digital signals
previously stored therein. Then, the read control circuit 40 is
made to successively transmit the stored longitude and latitude
signals one after another to the ship position signal generator 36.
Accordingly, electrical digital signals corresponding to the ship's
track on a magnified scale are stored in the display memory unit 8
as a result of which a magnified ship's track is plotted upon the
face 7 of the CRT.
The ship's track together with the longitude and latitude line
markers are displayed upon the face of the CRT and the displayed
pattern thereof can be magnified or reduced by means of the
magnifying switch 32 with the circuit shown in FIG. 7 in which the
circuits illustrated in FIGS. 5 and 6 have been combined.
Referring to FIG. 9, the construction and operation of the
longitude signal generator 25 will be explained. A reference marker
signal generating unit 45 produces a signal representing the
longitude of a reference longitude line marker positioned close to
a reference point, for example, the center of the display surface
of the CRT. A face edge signal generating unit 46 produces a signal
representing the longitude of the left-hand edge of the display
surface which a line marker signal generating unit 47 produces
signals representing each of the longitudes of the longitude line
markers displayed upon the face of the CRT. A subtractor 48
produces longitude differences signal by successively subtracting
each of the longitudes of the longitude line markers from that of
the reference point. A divider 49 divides each of the longitude
differences by a numerical value in accordance with the selected
scale of the pattern displayed upon the face of the CRT thereby
successively producing signals corresponding to each of the
longitude line markers with these signals being coupled to the
X-address register 18.
The reference marker signal generating unit 45 is constructed of a
setting unit 51, a divider 52 and a multiplier 53. The setting unit
51 produces a longitude difference signal representing the
longitude difference between two adjacent longitude line markers
displayed upon the face of the CRT with the longitude difference
signal being coupled to inputs of the divider 52 and the multiplier
53. The divider 52 divides the longitude of the reference point
signal, which is supplied to the other input, by the longitude
difference signal and couples a predetermined number of bits of the
quotient to the multiplier 53 with the remainder truncated. The
multiplier 53 multiplies the quotient by the longitude difference
signal thereby producing the longitude of the reference longitude
line marker.
The face edge signal generating unit 46 is constructed of a setting
unit 54, a multiplier 55 and a subtractor 56. The setting unit 54
transmits signal N representing half the width of the face of the
CRT to one input of the multiplier 55. The multiplier 55 multiplies
the distance of the width by the numerical value supplied to the
other input in accordance with the selected scale. The subtractor
56 subtracts the output signal from the multiplier from the signal
E representing the longitude of the reference point supplied
thereto thereby producing a signal representing the longitude of
the edge of the face of the CRT.
The line markers signal generating unit 47 includes a subtractor
57, a comparator 58, an accumulator 59 and a gate 90. The
subtractor 57 subtracts the output signal from the accumulator 59
from the longitude of the reference longitude line marker
transmitted by the unit 45, and transmits its output signal Z to
one inputs of the comparator 58 and the gate 90. The comparator 58
compares the output signal Z from the subtractor 57 and the signal
E from the face edge signal generating unit 46, and transmits an
output signal to the accumulator 59 and to the control input of the
gate 90 when the relationship between the input signals is E<Z.
The accumulator adds to a previously accumulated value stored
therein a signal representing the longitude difference between two
adjacent longitude line markers each time the signal is received,
the accumulated value being initially zero, and transmits the sum
to the subtractor 57. The gate 90 passes the signal Z, when the
signal is applied to the control input thereof, to one input of the
subtractor 48. The subtractor 48 successively subtracts each of the
longitudes of the longitude line markers supplied to one input
thereof from the longitude of the reference point supplied to the
other input. The divider 49 divides each of the longitude
differences from the subtractor 48 by the numerical value
transmitted thereto by the magnifying rate setting unit 31 thereby
successively producing the signals corresponding to the longitude
line markers displayed to the left of the reference point upon the
face of the CRT.
Similarly, the signals corresponding to the longitude line markers
displayed to the right of the reference point upon the face of the
CRT can also be obtained by a minor modification of the schematic
block diagram illustrated in FIG. 9. To do this, the subtractor 56
of the face edge signal generating unit 46 is to be replaced by an
adder with its two input terminals connected to receive the output
signals from the multiplier 55 and the longitude of the reference
point. The subtractor 57 of the line markers signal generating unit
47 is to be replaced by an adder which adds the output signals from
the reference marker signal generating unit 45 and the adder 59 to
one another. The comparator 58 should pass the signal Z and produce
a driving pulse to the adder 59 when the relationship therebetween
is E>Z.
In substantially the same manner, the signals corresponding to the
latitude line markers displayed upon the face of the CRT can be
obtained.
Referring to FIG. 9, in order to obtain the signals corresponding
to the latitude line markers displayed to the lower side of the
reference point upon the display surface, the latitude of the
reference point is to be applied to one input of the divider 52,
the subtractor 56 and the subtractor 48. Secondly, the setting unit
51 is to be connected so as to produce a latitude difference
between two adjacent latitude line markers displayed upon the face
of the CRT. Finally, the setting unit 54 is to be designed to
output a signal representing half the height of the display surface
of the indicator.
Further, in order to obtain the signals corresponding to the
latitude line markers displayed to the upper side of the reference
point upon the face of the CRT, referring to FIG. 9, first the
subtractor 56 is to be replaced by an adder. Secondly, the
subtractor 57 is to be replaced by an adder, and, thridly, the
comparator 58 is to pass the signal Z and produce a driving pulse
to the adder 59 when the mutual relationship is E>Z.
Referring to FIG. 10, the construction and operation of the ship
position signal generator 36 will be explained. The longitude of
the reference point signal supplied from the up-down counter 22 is
applied to one input of a subtractor 61 and the latitude of the
reference point supplied from the up-down counter 23 is applied to
one input of a subtractor 62. The longitude and latitude signals
representing the present ship's position are respectively supplied
to the other inputs of the subtractors 61 and 62 from the ship
position memory unit 34. The subtractor 61 subtracts, by way of
example, the longitude of the reference point from the longitude of
the present ship's position and produces in response thereto a
difference signal which is sent to a divider 63. The divider 63
divides the supplied difference signal by a numerical value
transmitted thereto from the magnifying ratio setting unit 31
thereby producing the signal corresponding to the ship's position
displayed upon the face of the CRT. The subtractor 62 subtracts the
latitude of the reference point from the latitude of the present
ship's position and produces therefrom a difference signal which is
coupled to a divider 64. The divider 64 divides the supplied
difference signal by the numerical value applied thereto by the
magnifying ratio setting unit 31 thereby producing the signal
corresponding to the ship's position.
Referring to FIG. 7, the operation of moving the displayed pattern
to a desired position upon the face of the CRT will be explained.
The displayed pattern includes the ship's track and the longitude
and latitude line markers.
A pattern moving switch 66 and an interface unit 67 are added to
the combination of the schematic diagrams of FIGS. 5 and 6. The
pattern moving switch 66 includes four switch elements 66l, 66r,
66u and 66d. The interface unit 67 supplies control signals to the
control input of the up-down counter 22 when either one of the
switch elements 66l or 66r is depressed and to the control input of
the up-down counter 23 when either one of the switch elements 66u
or 66d is depressed. The up-down counter 22 performs an
incrementing operation when the switch element 66r is depressed so
that the longitude numerical value of the reference point is
increased while the latitude numerical value thereof is held
constant. Conversely, when the switch element 66l is depressed, the
up-down counter 22 performs a decrementing operation so that the
longitude numerical value of the reference point is decreased.
Similarly, the up-down counter 23 increments the latitude numerical
value of the reference point when the switch element 66u is
depressed and decrements the latitude numerical value of the
reference point when the switch element 66d is depressed. The
interface unit 67 transmits a reset pulse to the display memory
unit 8 to clear the electrical signals stored in the memory unit 8
and a start pulse to the ship position memory unit at the moment
the depressed switch is restored thereby starting the successive
transmission of the stored signals one after another to the ship
position signal generator 36.
Accordingly, the displayed pattern moves to the right when the
switch element 66r is depressed and moves to the left when the
element 66l is depressed. Similarly, the displayed pattern moves
upwards when the switch element 66u is depressed and moves at a
predetermined angle of 45.degree. with respect to the horizontal
when the switch elements 66r and 66u are simultaneously
depressed.
Referring next to FIG. 8, the operation of the indicating cursor
line markers upon the face of the CRT will be explained. A cursor
marker switch 69 is made up of four switch elements 69l, 69r, 69u
and 69d. An interface unit 70 supplies control signals to the
control input of an up-down counter 71 when either one of the
switch elements 69l or 69r is depressed and to the control input of
an up-down counter 72 when either one of the switch elements 69u or
69d is depressed. The up-down counter 71 performs an incrementing
operation when the switch element 69r is depressed so that an
appropriate numerical value is transmitted to an NV-LL transformer
73 and to the X-address register 18 through the OR gate 27. The
counter 71 performs a decrementing operation when the switch
element 69l is depressed. The interface unit 70 transmits a driving
pulse to a counter 74 and a gate controller 75 at the moment when
one of the depressed switch elements 69l and 69r is restored. The
counter 74 successively produces increasing numerical values which
are sent to a gate 76 and to one input of the gate controller 75.
The gate controller 75 causes the gate 76 to intermittently pass
the output signals from the counter 74 to the Y-address register
19. The gate controller 75 comprises a counter which is put into
operation by the driving pulse from the unit 70 and senses to count
the change of the counted value produced by the counter 74 and
produces a control signal to the control input of the gate 76,
every time it counts the change up to a predetermined number, for
example up to three, thereby closing the gate 76 for a period and
hence causing it to intermittently pass the output signal from the
counter 74.
Elements of the X-address register 18 are identified by the
numerical values supplied thereto by the up-down counter 71. The
elements of the Y-address register 19 are successively
intermittently identified every predetermined number of elements
thereof by the output signals from the counter 74. Accordingly, the
display memory unit 8 writes 1's into the storage elements in the
column selected by the X-address register 18 thereby storing the
necessary signals to display a dotted cursor line marker parallel
to the longitude line markers.
Similarly, the up-down counter 72 performs an incrementing or a
decrementing operation when a corresponding one of the switch
elements 69u and 69d is depressed so that a numerical value is
transmitted to the NV-LL transformer 73 and also to the Y-address
register 19 through the OR gate 29. The interface unit 70 transmits
a driving pulse to a counter 77 and a gate controller 78 at the
moment when one of the depressed switch elements 69u and 69d is
restored. In substantially the same manner, a cursor line marker
parallel to the latitude line markers can be displayed at any
desired position upon the face of the CRT as in the case of
displaying a cursor line marker parallel to the longitude line
markers. The operation thereof is self-evident and hence need not
be repeated here.
Next, the operation of displaying the symbols for cursor line
markers will be explained. The NV-LL transformer 73 produces, in
response to the output signal from the up-down counter 71, a
numerical value corresponding to the longitude of the cursor line
marker displayed upon the face of the CRT and couples it to a
character generator 81. The NV-LL transformer also produces, in
response to the output signal from the up-down counter 72, a
numerical value corresponding to the latitude of a cursor line
marker and couples it to the character generator 81. The character
generator 81 successively produces numerical value signals which
are coupled to the X- and Y-address registers respectively, thereby
writing 1's into the storage elements selected by the registers 18
and 19. The stored electrical signals are read from the display
memory unit 8 and supplied to the indicator so that the symbols
indicating, for example, the longitude of a cursor line marker is
displayed at a position close to the line marker such as the symbol
5 illustrated in FIG. 1. The latitude symbol 6 for a cursor line
marker 4 is also indicated in the same manner.
Referring to FIG. 11, the NV-LL transformer 73 is constructed of a
multiplier 83 and an adder 84. The multiplier 83 multiplies the
output signal from the up-down counter 71 by the numerical value
relating to the selected scale of the displayed pattern supplied
from the magnifying rates setting unit 31. The adder 84 adds the
product signal to the signal representing the longitude of the left
edge of the face of the CRT thereby producing a signal representing
the longitude of a cursor line marker. Similarly, the latitude
numerical value of a cursor line marker is obtained by replacing
the up-down counter 71 with the up-down counter 72 and by supplying
to the adder 84 the latitude of a lower edge of the face of the
CRT.
Referring to FIG. 4, a detailed schematic block diagram is shown
which combines the schematic diagrams illustrated in FIGS. 7 and
8.
When it is desired to move the cursor line marker which is parallel
to the longitude line markers to the right direction, the switch
element 69r is depressed. The interface unit 70 then transmits a
reset pulse to the display memory unit 8 and a start pulse to the
read control circuit 40 at the moment when the depressed switch
element is restored. The display memory unit 8 is first cleared,
and then 1's are written into the storage locations selected based
on the output signals from the up-down counters 71, 72, the
longitude and latitude signal generators 25, 26, and the ship
position memory unit 34. As a result, a cursor line marker as well
as the ship's track and the longitude and latitude line markers are
displayed at a new positions.
When it is desired to magnify or reduce the displayed pattern
wherein the cursor line markers as well as the ship's track and the
longitude and latitude line markers are all simultaneously
magnified or reduced, the magnifying switch 32 is depressed thereby
moving the ship's track and the longitude and latitude line markers
to new positions. However, the cursor line markers continue to be
displayed at the same positions with the symbols indicating the
longitude and latitude of the line markers changing with the
magnification ratio of the displayed pattern.
When it is desired to move the displayed pattern, for example, to
the right, the switching element 66r is depressed thereby moving
the ship's track and the longitude and latitude line markers to new
positions but maintaining the cursor line markers at the same
positions. Moreover, the symbols indicating the longitude and
latitude of the cursor line markers also change with movement of
the displayed pattern.
Referring to FIG. 12, the construction and operation of an
automatic pattern shifter will be explained. For the purpose of
this explanation, it is assumed that the ship is moving to the left
upon the face of the CRT. An automatic pattern shifter 85 includes
a comparator 86 and a control signal generator 87 with an adjusting
switch 88. The comparator 86 compares the longitude of the ship's
present position P supplied from the ship position memory unit 34
and the longitude E of the left-hand edge of the face of the CRT
supplied from the face edge signal generating unit 46 and produces
in response thereto a driving pulse which is coupled to the control
signal generator 87 when the mutual relationship therebetween is
E>P. The control signal generator 87 produces control signals
which are coupled to the up-down counter 22 which in response
thereto decrements its numerical value by a predetermined amount so
that the present ship's position is moved to the right to a new
position determined by the predetermined amount of change. The
amount of decrement can be varied by the adjusting switch 88.
Similarly, the displayed pattern can be automatically shifted in
the opposite direction to the direction of movement of the ship
when the ship goes beyond the right-hand edge of the face of the
indicator. In this case, the face edge signal generating unit 46
supplies the longitude of the right-hand edge of the display
surface and the control signal generator 87 causes the up-down
counter 22 to increment its numerical value by a variable
predetermined amount.
In the same manner, the displayed pattern can be automatically
shifted upwardly or downwardly when the ship goes beyond the lower
or upper edge of the face of the CRT. For this, a control signal
from the control signal generator 87 is supplied to the up-down
counter 23 and the face edge generating unit 46 applies a signal
representing the latitude of the lower or upper edge of the
face.
It should be noted that the indicator used with the invention is
not limited to a CRT as used in the embodiments described above.
For example an array of light-emitting diodes, a plasma display or
any of a number of other display devices can also used instead.
While the invention has been described in detail and with reference
to specific embodiments thereof, it will be apparent to one skilled
in the art that various changes and modifications can be made
thereto without departing from the spirit and scope of the
invention.
* * * * *