Integrated flight information and control system
First Claim
1. A navigation system for mounting on a vehicle for determining the stability axis flight path angle γ
- and stability axis roll angle φ
s of said vehicle while undergoing arbitrary but balanced maneuvers along a flight path through space with respect to a reference frame, said system comprising;
A. a navigation processor including;
(1) measuring means for measuring at least one of the position or velocity of said vehicle as it moves along said path;
(2) means responsive to said measurements for extracting estimates of the velocity and acceleration of said vehicle at successive positions along said path; and
(3) processing means for calculating the flight path angle γ and
stability axis roll angle φ
s corresponding to said estimates; and
B. a navigation display for displaying said angles for navigating said vehicle in accordance therewith.
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Abstract
An improved navigation and display system especially suitable for small aircraft rapidly determines the attitude (roll and pitch) of an aircraft from measurements made by an inexpensive, single receiver and antenna responsive to signals obtained from a satellite positioning system, e.g., the Global Positioning System. In contrast to conventional attitude navigation systems, which determine and display conventional (body-axis referenced) pitch angle, the present system determines and displays the “pseudo-attitude” or stability axis roll and pitch (flight path) angle, so that the pilot has an instantaneous comprehension of the actual flight path angle of the aircraft without needing to correct for angle of attack as in conventional attitude information systems. A Kalman filter with a short (˜0.5 second) time constant provides data at a sufficient rate (e.g., ˜10 Hz) to enable real-time flight with the system. With the additional availability of measured or estimated angle of attack, this system can also display conventional roll and pitch attitude angles. The pseudo-attitude data is incorporated into an integrated flight information system which derives all its data from the single GPS sensor and which presents all the information needed for navigation and control of the aircraft in which it is mounted.
155 Citations
40 Claims
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1. A navigation system for mounting on a vehicle for determining the stability axis flight path angle γ
- and stability axis roll angle φ
s of said vehicle while undergoing arbitrary but balanced maneuvers along a flight path through space with respect to a reference frame, said system comprising;A. a navigation processor including;
(1) measuring means for measuring at least one of the position or velocity of said vehicle as it moves along said path;
(2) means responsive to said measurements for extracting estimates of the velocity and acceleration of said vehicle at successive positions along said path; and
(3) processing means for calculating the flight path angle γ and
stability axis roll angle φ
s corresponding to said estimates; and
B. a navigation display for displaying said angles for navigating said vehicle in accordance therewith. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
A. having at least three integrators for forming estimates of jerk, acceleration, and velocity;
B. receiving as inputs said position measurements; and
C. providing as outputs at least said velocity and acceleration estimates for said processing means.
- and stability axis roll angle φ
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3. A navigation system according to claim 2 in which said filter is characterized by a response time sufficiently short as to enable real-time navigation of said vehicle in accordance with said display.
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4. A navigation system according to claim 3 in which said response time is of the order of less than one second.
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5. A navigation system according to claim 2 in which said filter receives as further input a process noise variance characteristic of the vehicle in which said navigation system is mounted.
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6. A navigation system according to claim 5 provided in a single unit transportable from vehicle to vehicle.
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7. A navigation system according to claim 1 in which said filter comprises a plurality of separate and independent filters, each providing a component of the vehicle velocity as output therefrom for calculation of said flight path angle γ
- in accordance therewith.
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8. A navigation system according to claim 1 in which said position measuring means comprises a single satellite positioning system receiver providing measurements of the position of said vehicle with respect to an earth-based reference system.
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9. A navigation system according to claim 8 in which said processing means determines from said velocity and acceleration estimates a local horizontal reference relative to said reference frame and associated with said estimates and thereafter determines said stability roll angle φ
- s therefrom.
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10. A navigation system according to claim 1 in which the flight path angle γ
- and stability axis roll angle φ
s provide the primary attitude information from which the vehicle is maneuvered.
- and stability axis roll angle φ
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11. A navigation system according to claim 1 in which the flight path angle γ
- and stability axis roll angle Us provide supplemental attitude information in connection with maneuver of the vehicle.
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12. A navigation system according to claim 1 in which said estimate extracting means including a Kalman filter having multiple integrators for providing said velocity and acceleration estimates and characterized by a response time sufficiently short as to enable real-time control of the attitude of said vehicle in accordance with said display.
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13. A navigation system according to claim 12 in which said processing means determines from said velocity and acceleration estimates a local horizontal reference relative to said reference frame and associated with said estimates and thereafter determines said stability roll angle φ
- s therefrom.
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14. A navigation system for determining the stability axis flight path angle γ
- of a vehicle undergoing arbitrary but balanced maneuvers along a flight path through space with respect to a reference frame, comprising;
A. means for measuring at least the position or velocity of the vehicle with respect to said frame as it undergoes said maneuvers;
B. means responsive to said position measurements for determining the velocity of said vehicle along said path;
C. means for calculating said flight path angle from said velocity. - View Dependent Claims (15, 16, 17, 18, 19, 20)
- of a vehicle undergoing arbitrary but balanced maneuvers along a flight path through space with respect to a reference frame, comprising;
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21. Apparatus for determining the conventional attitude of an aircraft undergoing arbitrary flight path maneuvers, comprising:
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A. means providing measurement of the stability axis flight path velocity and acceleration of the aircraft in a first, locally stationary frame;
B. means for determining the stability axis flight path angle of the aircraft in a second, stability frame, from orthogonal velocity components measured in said first frame;
C. means for determining the roll of the aircraft in said second frame in an arbitrary but balanced banking maneuver from the aircraft velocity measured in said first frame, the lift in said second frame as determined from the normal flight path acceleration component in said second frame, and the gravitational acceleration component in said second frame normal to the flight path;
D. means for determining the angle-of-attack of said aircraft; and
E. means for transforming the pitch and roll in said second frame to a third, body-axis frame in accordance with said angle of attack.
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22. A method of navigating a vehicle through space along an arbitrary flight path while undergoing arbitrary but balanced maneuvers with respect to a reference frame, comprising:
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A. repeatedly measuring at least one of position or velocity of the vehicle as it undergoes said maneuvers;
B. forming estimates of the velocity and acceleration of said vehicle at said positions from said measurements;
C. determining the stability axis flight path angle γ
from said velocity estimates;
D. determining from said velocity and acceleration estimates a local horizontal reference corresponding thereto;
E. determining the stability axis roll angle Us with respect to said local horizontal reference;
F. navigating said vehicle in accordance with the calculated flight path angle γ and
stability axis roll angle φ
s.- View Dependent Claims (23, 24, 25, 26, 27, 28, 29)
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30. An integrated flight information and control system for navigation and control of a vehicle, comprising:
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A. means in said vehicle for determining the position and velocity of said vehicle; and
B. means responsive to outputs from said determining means for determining navigation and control parameters for said vehicle, said parameters including at least the stability axis pseudo-attitude of said vehicle. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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Specification