AIRCRAFT GLIDE SLOPE INSTRUMENTATION SYSTEM

• US 3,781,891 A
• Filed: 04/17/1972
• Issued: 12/25/1973
• Est. Priority Date: 04/17/1972
• Status: Expired due to Term

• Current Assignee: Robert R. Moose
• Original Assignee: Robert R. Moose
• Inventors: Moose, Robert R.
• Primary Examiner(s): Borchelt, Benjamin A.
• Assistant Examiner(s): Berger, Richard E.
• Application Number:
  US05/244,830
• Time in Patent Office: 617 Days
• Field of Search: 343/18R 235/150.22
• US Class Current: 342/411
• CPC Class Codes: G01S 1/02 using radio waves G01S19/00 takes precedence

Abstract

An aircraft glide slope instrumentation system for use with an altimeter means equipped aircraft and a landing strip, the instrumentation system comprising a pair of ground-based transmitter beacons spaced a fixed distance apart, a first direction-finding receiver carried by the aircraft for receiving the output of one of the transmitter beacons and determining the azimuth bearing thereof, a second direction-finding receiver carried by the aircraft for receiving the output of the other transmittter beacon and determining the azimuth bearing thereof, distance computer means carried by the aircraft and operably connected to the two receivers for determining the horizontal distance between the aircraft and the landing strip based on the difference in relative bearing of the two transmitter beacons, altitude computing means carried by the aircraft and operably connected to the distance computer means for determining the desired landing approach altitude of the aircraft at any time during the approach thereof and glide slope display means operably connected to the altitude computing means and the aircraft altimeter means for displaying the difference between the desired landing approach altitude and the true altitude of the aircraft with respect to the landing strip.

Claims

1. An aircraft glide slope instrumentation system for providing vertical guidance to an aircraft equipped with altimeter means for landing at a landing strip, the instrumentation system comprising a pair of landing strip based transmitter beacons spaced a fixed distance apart, a first direction finding receiver carried by the aircraft for receiving the output of one of the transmitter beacons and determining the azimuth bearing thereof, a second direction finding receiver carried by the aircraft for receiving the output of the other transmitter beacon and determining the azimuth bearing thereof, distance computer means carried by the aircraft and operably connected to the two receivers for determining the horizontal distance between the aircraft and the landing strip based upon the difference in relative bearing between the two transmitter beacons when the said aircraft is in longitudinal alignment with the center line of said landing strip by use of suitable localizer means, altitude computing means carried by the aircraft and operably connected to the distance computer means for determining the desired landing approach altitude of the aircraft at any time during the approach thereof and glide slope display means operably connected to the altitude computing means and the altimeter means for displaying the difference between the desired landing approach altitude and the true altitude of the aircraft with respect to the landing strip.

2. An aircraft glide slope instrumentation system as set forth in claim 1 wherein the landing strip based transmitter beacons comprise a first nondirectional radio beacon transmitter disposed on an extension of the center line of the landing strip and spaced a fixed distance from one end of the said landing strip and a second nondirectional radio beacon transmitter disposed a fixed distance from the mid-point of the landing strip on a line perpendicular to and interesecting with the center line of the landing strip at the said mid-point of the landing strip.

3. An aircraft glide slope instrumentation system as set forth in claim 1 wherein each of the direction finding receivers comprises an airborne direction finding receiver having servo voltage outputs corresponding to the aximuth bearing of the ground based transmitter beacon to which it is tuned.

4. An aircraft glide slope instrumentation system as set forth in claim 3 wherein the distance computer means comprises differential servo means operably connected to the servo voltage outputs of the direction finding receivers for determining the difference in relative azimuth bearing between the ground based transmitter beacons and a potentiometer means having a specially wound nonlinear variable resistive element and a movable wiper arm in movable contact with the said variable resistive element, the said wiper arm being operably connected to the output of the differential servo means, the movement of the said wiper arm being directly proportional to the difference in relative bearing between the transmitter beacons which is directly proportional to the arc contangent of the horizontal distance from the aircraft to the landing strip.

5. An aircraft glide slope instrumentation system as set forth in claim 4 wherein the altitude computing means comprises a resistance means operably connected to the potentiometer means for determining the desired landing approach altitude of the aircraft above the landing strip at any time during the approach thereof based upon the horizontal distance of the said aircraft from the landing strip.

6. An aircraft glide slope instrumentation system as set forth in claim 5 wherein the aircraft altimeter means comprises an altimeter for measuring the altitude of the aircraft above sea level, the said altimeter having voltage servo output directly proportional to the said altitude above sea level, altimeter driven variable resistor means, altimeter servo means operably connected to the output of the altimeter and the variable resistor means for varying the resistance of the said variable resistor means directly proportionate to the altitude of the aircraft above sea level, manually adjustable landing strip elevation variable resistor means operably connected to the altimeter driven variable resistor means for adjusting the total resistance of the altimeter driven variable resistor means and the landing strip elevation variable resistor means whereby the said total resistance is directly proportional to the altitude of the aircraft above the landing strip.

7. An aircraft glide slope instrumentation system as set forth in claim 6 wherein the glide slope display means comprises a current sensitive galvanometer type meter having a movable display indicator, the movement thereof being directly proportional to the difference between the desired landing approach altitude of the aircraft and the true altitude of the aircraft with respect to the landing strip.

8. An aircraft glide slope instrumentation system as set forth in claim 7 wherein the altitude computing means is provided with landing strip length adjustment means for adjusting the landing point with respect to the mid-point of the landing strip to compensate for landing strips of various lengths.

9. An aircraft glide slope instrumentation system as set forth in claim 7 wherein automatic glide slope sensitivity control means is operably connected to the glide slope display means for varying the sensitivity of the said glide slope display means inversely proportional to the desired landing approach altitude of the aircraft above the landing strip.

10. An aircraft glide slope instrumentation system as set forth in claim 4 wherein the distance computer means also comprises a missed approach point indication means for indicating when the aircraft has passed the said missed approach point.

11. An aircraft glide slope instrumentation system as set forth in claim 10 wherein the missed approach point indication means comprises a plurality of resistors arranged in a divided bridge circuit, a current sensitive flag display meter connected across the said bridge circuit, a bridge balancing potentiometer having a resistive element connected to one branch of the bridge circuit, and a movable wiper arm electrically connected to the flag display meter, the said wiper arm being operably connected to the output of the differential servo means, the movement of the said wiper arm being effected by the said differential servo means and directly proportional to the differEnce in relative bearing between the transmitter beacons for decreasing the current through the flag display meter whereby upon reaching the missed approach point, the said flag display meter indicates that the aircraft has passed the said missed approach point.

12. An aircraft glide slope instrumentation system as set forth in claim 11 wherein missed approach sensitivity adjustment means is operably connected to the flag display meter for adjusting the missed approach indication thereof longitudinally with respect to the landing strip.

13. An aircraft glide slope instrumentation system for providing vertical guidance to an aircraft equipped with altimeter means for landing at a landing strip, the instrumentation system comprising a pair of landing strip based transmitter beacons spaced a fixed distance apart, the first said beacon being disposed in longitudinal alignment with the landing strip and spaced a fixed distance from one end thereof and the second beacon disposed a fixed distance from the mid-point of the landing strip on a line perpendicular to the center line of the landing strip and intersecting the said landing strip at the mid-point thereof;

a first direction finding receiver carried by the aircraft for receiving the output of the first transmitter beacon and determining the azimuth bearing thereof, a second direction finding receiver carried by the aircraft for receiving the output of the second transmitter beacon for determining the azimuth bearing thereof, each of the said receivers having a servo output corresponding to the azimuth bearing of the transmitter beacon to which it is tuned;

distance computer means carried by the aircraft and comprising differential servo means operably connected to the servo outputs of the direction finding receivers for determining the difference in relative azimuth bearing between the said transmitter beacons, the output of the said differential servo means being directly proportional to the difference in relative azimuth bearing between the transmitter beacons, a first potentiometer means having a specially wound non-linear resistive element and a movable wiper arm in movable contact with the said non-linear resistive element, the said wiper arm being operably connected to the output of the differential servo means, the movement of the said wiper arm being directly proportional to the difference in relative azimuth bearing between the transmitter beacons for determining horizontal distance between the aircraft and the landing strip based upon the difference in relative bearing between the two transmitter beacons when the said aircraft is in longitudinal alignment with the center line of said landing strip by use of suitable localizer means;

a missed approach point indicator comprising a plurality of resistors arranged in a divided bridge circuit, a current sensitive flag display meter connected across the said bridge circuit, a bridge balancing potentiometer having a resistive element connected to one branch of the bridge circuit and a movable wiper arm electrically connected to the flag display meter, the said wiper arm being operably connected to the output of the differential servo means, the movement of the said wiper arm being directly proportional to the difference in relative azimuth bearing between the transmitter beacons for providing indication when the aircraft has passed the missed approach point;

altitude computing means carried by the aircraft and connected to the distance computer means, the said altitude computing means comprising a plurality of resistor means operably connected to the distance computer means in a divided bridge circuit, for determining the desired landing approach altitude of the aircraft above the landing strip at any time during the approach thereof based on the horizontal distance of the said aircraft from the landing strip; and

glide slope display means comprising a current sensitive galvanometer type meter having a movable display indicator, the said glide slope display meTer being operably connected to the altitude computing means and the altimeter means, the movement of the movable display indicator being directly proportional to the difference between the desired landing approach altitude of the aircraft and the true altitude of the aircraft with respect to the landing strip.

14. An aircraft glide slope instrumentation system for providing vertical guidance to an aircraft equipped with altimeter means for landing at a landing strip, the instrumentation system comprising at least two landing strip based transmitter beacons spaced a fixed distance apart, a first direction finding receiver carried by the aircraft for receiving the output of one of the transmitter beacons and determining the azimuth bearing thereof, a second direction finding receiver carried by the aircraft for receiving the output of one of the other transmitter beacons and determining the azimuth bearing thereof, distance computer means carried by the aircraft and operably connected to the two receivers for determining the horizontal distance between the aircraft and the landing strip based upon the difference in relative bearing between the two transmitter beacons when the said aircraft is in longitudinal alignment with the center line of said landing strip by use of suitable localizer means, altitude computing means carried by the aircraft and operably connected to the distance computer means for determining the desired landing approach altitude of the aircraft at any time during the approach thereof and glide slope display means operably connected to the altitude computing means and the altimeter means for displaying the difference between the desired landing approach altitude and the true altitude of the aircraft with respect to the landing strip.