AIRCRAFT HORIZONTAL SITUATION NAVIGATION DISPLAY SYSTEM

• US 3,696,671 A
• Filed: 09/18/1970
• Issued: 10/10/1972
• Est. Priority Date: 09/18/1970
• Status: Expired due to Term

• Current Assignee: Charles J. Steigleder, Linual D. Smithey, Lloyd E. Lydon
• Original Assignee: Charles J. Steigleder, Linual D. Smithey, Lloyd E. Lydon
• Inventors: Steigleder, Charles J., Smithey, Linual D., Lydon, Lloyd E.
• Primary Examiner(s): Woodiel, Donald O.
• Application Number:
  US05/073,399
• Time in Patent Office: 753 Days
• Field of Search: 73/178R,178T,178H 340/27 353/11,12
• US Class Current: 73/178.00R
• CPC Class Codes: G01C 21/22 Plotting boards
• CPC Class Codes: G01S 1/02 using radio waves G01S19/00 takes precedence

Abstract

A display system is disclosed for a navigation director system in which a portion of an azimuth stabilized navigation chart is displayed optically with the aircraft position on the chart at the center of the display, and a selected radial course for VOR airway navigation is displayed optically as a course bearing indicator (CBI) in the form of an arrow that points to a course bearing on an azimuth stabilized compass ring. The center of the arrow is replaced by a lateral deviation bar (LDB) that is displaced from the CBI in proportion to the angular deviation of aircraft position from the selected course. For area navigation between selected way points on the chart, the CBI is positioned to indicate the course bearing of a computed great circle route and the LDB is displaced in proportion to the cross-track distance off course. For conventional VOR navigation, the chart display may be independently turned off.

Claims

1. In an aircraft horizontal situation navigation display system, in which an azimuth stabilized image of a chart is optically projected onto a display surface within an azimuth stabilized compass ring for continual display of a portion of said chart image with aircraft position on said chart image always centered on said display surface under control of a computer in a navigation director system, said navigation director system having a receiver for producing a signal proportional to angular deviation of said aircraft position from a selected flight path on said chart with proper sign for the direction of the deviation, the combination comprising:

means for selecting a flight path;

means for optically displaying on said surface a course bearing indicator in the form of an arrow along a diameter of said compass ring;

means responsive to said flight path selecting means for rotating said course bearing indicator on said display relative to said compass ring until it points to the bearing of the flight path selected, and for azimuth stabilizing said arrow as said aircraft changes heading;

means for optically displaying on said surface a lateral deviation bar azimuth stabilized and rotated in synchronism with said course bearing iNdicator with the length of said bar parallel to the length of said course bearing indicator; and

means responsive to said angular deviation signal for displacing said lateral deviation bar a perpendicular distance from said course bearing indicator proportional to the amplitude of said signal in a direction corresponding to the sign of said signal.

2. In an aircraft horizontal situation navigation display system, in which an azimuth stabilized image of a chart is optically projected onto a display surface within an azimuth stabilized compass ring for continual display of a portion of said chart image with aircraft position on said chart image always centered on said display surface under control of a computer in a navigation director system, said navigation director system having a receiver for producing a signal proportional to angular deviation of said aircraft position from a selected flight path on said chart, the proper sign for the direction of the deviation, wherein said computer calculates a navigation route between two specified points on said chart and continually produces a first signal proportional to the difference between aircraft heading and a course bearing of said route, and a second signal proportional to lateral deviation of said aircraft position from said route with proper sign for the direction of the deviation, where said lateral deviation is a measure of distance from said aircraft position at any given time to said route along a line perpendicular thereto, the combination comprising:

means for selecting a flight path;

means for optically displaying on said surface a course bearing indicator in the form of an arrow along a diameter of said compass ring;

means responsive to said flight path selecting means for rotating said course bearing indicator on said display relative to said compass ring until it points to the bearing of the flight path selected, and for azimuth stabilizing said arrow as said aircraft changes heading;

means for optically displaying on said surface a lateral deviation bar azimuth stabilized and rotated in synchronism with said course bearing indicator with the length of said bar parallel with the length of said course bearing indicator;

means responsive to said angular deviation signal for displacing said lateral deviation bar a perpendicular distance from said course bearing indicator proportional to the amplitude of said signal in a direction corresponding to the sign of said signal;

means for selectively altering said rotating means for said course bearing indicator to rotate said course bearing indicator relative to aircraft heading on said compass ring in accordance with said first signal;

means for selectively substituting said second signal for said angular deviation signal for displacing said lateral deviation bar a perpendicular distance from said course bearing indicator a distance proportional to the amplitude of said second signal in a direction corresponding to the sign of said second signal; and

switching means for simultaneously actuating said means for selectively altering said rotating means and said means for selectively substituting said second signal for said angular deviation signal.

3. In a display system as defined in claim 2, the combination including:

means for interrupting the projection of said chart image on said display surface; and

means for selectively actuating said interrupting means, whereby said course bearing indicator and said lateral deviation bar may be displayed for VOR navigation without display of a chart.

4. In a display system, the combination as defined in claim 3 wherein said flight path is a radial of a VOR station, and said receiver is a VOR receiver.

5. In a display system, the combination as defined in claim 4 wherein said navigation route calculated by said computer is a great circle route.

6. In a flight navigation system for an aircraft, said system having computing means for determining a navigation roUte as a desired flight path between any two specified way points on a chart, continually determining aircraft position and continually producing a route bearing signal proportional to a compass bearing of said route and a linear deviation signal proportional to the linear deviation of said computed aircraft position from said route along a line perpendicular to said route, said system also having means for continually receiving a VOR radial signal from a selected station and for producing an angular deviation signal proportional to angular deviation of actual aircraft position from a selected radial, the combination comprising:

a display unit including a display surface, the center of said surface representing the position of said aircraft;

means for displaying a compass ring centered on said surface and stabilized in azimuth as said aircraft changes heading;

means for displaying a course bearing indicator in alignment with said center and a given bearing on said ring, said given bearing being a function of a given flight path desired;

means for selecting a radial of a VOR station as a desired flight path;

means responsive to said selecting means for producing a radial bearing signal proportional to the compass bearing of said radial course selected;

means for displaying a lateral deviation bar on said surface at a distance from said center in response to a selected one of said linear and angular deviation signals; and

switching means for connecting to said course bearing indicator display means a selected one of said radial bearing and computed route bearing signals, and for simultaneously connecting to said lateral deviation bar display means a corresponding one of said angular and linear deviation signals.

7. The combination as defined in claim 6 including:

means for displaying only a portion of said chart, said portion being a small fraction of the total chart;

means for continually selecting said portion of said chart to include said aircraft position on said chart at said center of said display surface; and

means for continually stabilizing said chart display means in azimuth as said aircraft changes heading.

8. The combination as defined in claim 7 wherein said course bearing indicator is a discontinuous line display on said surface with an arrowhead at one end for pointing to a bearing on said compass ring, said line being a diameter of said ring with a center portion of said line omitted, and said lateral deviation bar is a line approximately equal in length to said center portion omitted from said first symbol line, said lateral deviation bar being disposed parallel to said course bearing indicator in said display unit, and both said course bearing indicator and said lateral deviation bar are superimposed on said portion of said chart displayed.

9. The combination as defined in claim 8 wherein said surface comprises an optical display surface, and said means for displaying only a portion of said chart, and said means for superimposing said course bearing indicator and said lateral deviation bar on said portion, comprise:

optical means for projecting an image of said chart portion onto said surface;

optical means for projecting an image of said course bearing indicator and lateral deviation bar properly spaced onto said surface; and

means for selectively interrupting the projection of an image of said chart portion.

10. In an aircraft horizontal situation display system for a navigation director system in which an azimuth stabilized image of a chart is optically projected onto a display surface within an azimuth stabilized compass ring for continual display of a portion of said chart image, with aircraft position on said chart image always centered on said display surface under control of a computer in a navigation director system, said navigation director system having two navigation systems for selecting a flight path, each navigation system producing a first signal proportional to course bEaring of a selected flight path, and a second signal proportional to lateral deviation of aircraft position from said selected flight path, the combination in an aircraft comprising:

means for superimposing an image of a course bearing indicator on said chart portion projected onto said surface as a diameter of said compass ring with a center section omitted and an arrow to point to a desired course bearing on said compass ring;

means for superimposing a lateral deviation bar image on said chart portion projected onto said surface in a position parallel to and laterally in line with said omitted portion of said course bearing indicator, but displaced therefrom laterally a distance said aircraft position is off said desired flight path;

means for controlling said distance as a function of a second signal from a selected one of said two navigation systems;

means for controlling the bearing on said compass card to which said course bearing indicator points as a function of a first signal from a selected one of said two navigation systems; and

means for selecting one of said two navigation systems for display of course bearing and deviation of aircraft position from a desired flight path.

11. The combination as defined in claim 10 wherein:

one of said two navigation systems is for navigating a flight path along a selected line established by radio transmission of a signal from a ground station to said aircraft, and deviation from said radio established flight path is an angular value, the magnitude of which is proportional to lateral displacement of said lateral deviation bar from said course bearing indicator; and

the other of said two navigation systems is for navigating a flight path between two designated points on a chart along a predetermined line calculated by a computer of a navigation director system, and deviation from said computer calculated flight path is a linear value the magnitude of which is proportional to lateral displacement of said lateral deviation bar from said course bearing indicator.

12. The combination as defined in claim 11 including means for selectively interrupting the optical display of said chart while selecting for display said one system for navigating a flight path along a selected line established by radio transmission of a signal from a ground station.

13. In an aircraft navigation system of the type including an optical display surface within an azimuth stabilized compass ring, said surface having a center which represents the position of an aircraft, said system having means for displaying a portion of an azimuth stabilized chart on said surface with the position of said aircraft on said chart at said center of said display, said system being operable in an area navigation flight made in which a course bearing indicator is superimposed on said chart portion displayed at an angle with a diameter passing through a mark on said compass ring representing aircraft heading, said angle being equal to the difference between the bearing of an established route and the heading of said aircraft in response to a signal phi proportional thereto from a computer which establishes said route, and a lateral deviation bar is superimposed on said chart portion displayed at a distance from said center which corresponds to the off-route error of said aircraft, and in parallel with said course bearing indicator, in response to a signal Rho proportional thereto from said computer which establishes said route, the improvement comprising:

means responsive to said signal phi for rotating said course bearing indicator about said display center, whereby its angular position with respect to said diameter passing through aircraft heading represents only the course bearing of said route on said chart;

means for selectively modifying said system for operation in a radio station radial flight made in which an azimuth stabilized course bearing indicator is displayed to show on said compass ring the bearing oF a selected radial line from a radio station; and

means responsive to said selectively modifying means for substituting a signal Rho '"'"''"'"' for said signal Rho , where Rho '"'"''"'"' is a signal produced by radio receiving means for radial flight navigation, said signal Rho '"'"''"'"' being proportional to angular deviation of aircraft position from said selected radial line.

14. The improvement in an aircraft navigation system as defined by claim 13 wherein said means for selectively modifying said system for operation in a radio station radial flight made comprises means for substituting a signal phi '"'"''"'"' for said signal phi , and said signal phi '"'"''"'"' is produced by a differential transformer selectively connected in series between an input selsyn and an output selsyn of a selsyn repeating system, said selsyns having stator coils coupled to each other by said differential transformer, means coupling a rotor coil of said input transformer to said azimuth stabilized azimuth ring for rotation as aircraft heading changes, and a radial course selecting means coupled to said differential transformer for rotating the primary thereof relative to the secondary thereof through an angle from a reference position, said angle corresponding to the radial selected, whereby one rotor coil of said output selsyn produces a signal for stabilizing said course bearing indicator during a radial flight navigation made at a selected radial bearing as said aircraft changes heading.

15. The improvement in an aircraft navigation system as defined by claim 14 wherein said means for selectively modifying said system for operation in a radio station radial flight made comprises a first group of switches which, when a radial flight made is not selected, connect corresponding stator coils of said input and output selsyns directly, connect two orthogonal rotor coils of said output selsyn to said computer for calculation of said signal phi from aircraft heading data produced by said orthogonal stator coils, and to apply said signal phi from said computer in place of said signal phi '"'"''"'"' from said one rotor coil of said output selsyn.