Patent EP0617259A1 successfully refreshed from Google Patents.
EP0617259A1
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Method for calibrating aircraft navigation systems
Assignee: Northrop Grumman Guidance and Electronics Co Inc
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Filing: 1993-12-01
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Granted: —
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Expires: 2013-12-01
Abstract
Abstract A method and apparatus for minimizing the effect of lateral velocity transients upon an aircraft inertial instrument calibration process of the type in which cross-track velocity is measured and utilized to correct for the east component of gyro bias error. A "cross-track position" value is obtained by integration of the cross-track velocity. A Kalman filter 22 calculates a plurality of gain values corresponding to measurements of crab angle, lever arm, north and east velocity, heading angle and rate of change of heading angle and those gain values are applied to the cross-track position value to obtain error values for each of such parameters. The calculated error values are then employed as corrections to, or calibrations of, the inertial instrument outputs.
Inventors
- 👤 John W. Diesel
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 23:32
CPC Classifications
G; G01; G01C; G01C25/00; G01C25/005; G01C21/00; G01C21/10; G01C21/12; G01C21/16; G01C21/166
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
161 words
A method for calibrating an aircraft's inertial navigation system using the cross-track velocity (V CT ) of said aircraft, the method comprising the steps of: a) determining north velocity (V N ), east velocity (V E ), heading (ψ H ) and time derivative of heading (ψ̇ H ); b) determining crab angle (β); c) determining lever arm (R L ); d) determining the integral of cross track velocity (V CT ) from V N , V E , ψ H , ψ̇ H , R L and β to obtain the cross-track position P CT ; e) determining Kalman gain values for V N , V E , ψ H , ψ̇ H , R L and β; f) multiplying said Kalman gain values by said cross-track position P CT to determine V N , V E , ψ H , ψ̇ H , R L and β errors; and g) employing said errors to calibrate said inertial navigation system.
Claim 2
Dependent Claim
37 words
A method according to claim 1, comprising determining the north velocity (V N ), east velocity (V N ), heading (ψ H ) and time derivative of heading (ψ̇ H ) with an inertial reference system (14).
Claim 3
Dependent Claim
59 words
A method according to claim 1 or 2, wherein step d) comprises the step of determining the cross heading velocity (V C ) and the heading velocity (V H ) as a function of V N , V E and ψ H and the step of determining the integral of V CT from V C and V H .
Claim 4
Dependent Claim
46 words
A method according to claim 3, wherein V C and V H are determined according to the relationships: V C = V E cos ψ H - V N sin ψ H V H = V E sin ψ H + V N cos ψ H
Claim 5
Dependent Claim
22 words
A method according to claim 3 or 4, wherein V C and V H are determined using a velocity computation circuit (16).
Claim 6
Dependent Claim
35 words
A method according to claim 3, 4 or 5, wherein V CT is determined according to the following relationship: V CT = V C - V H sinβ - R L ψ̇ H .
Claim 7
Independent Claim
24 words
A method according to any one of the preceding claims, wherein the step of determining β comprises the step of integrating the β error.
Claim 8
Independent Claim
26 words
A method according to any one of the preceding claims, wherein the step of determining R L comprises the step of integrating the R L error.
Claim 9
Dependent Claim
164 words
Apparatus for calibrating the inertial navigation system of a taxiing aircraft comprising: a) means (14) for measuring north velocity (V N ), east velocity (V E ), heading (ψ H ) and rate of change of heading (ψ̇ H ); b) means (18) for providing crab angle (β); c) means (20) for providing lever arm (R L ); d) means (16) for determining the integral of cross track velocity (V CT ) from V N , V E , ψ H , ψ̇ H , R L and β to obtain the cross-track position P CT ; e) a Kalman filter (22) for receiving said values of V N , V E , ψ H , ψ̇ H , R L and β and providing gain values in response thereto; f) means (24) for multiplying said cross-track position P CT by said gain values; and g) means for accepting the output of said last-named means for calibrating said inertial navigation system in response thereto.
Claim 10
Dependent Claim
39 words
Apparatus according to claim 9, wherein said means (14) for measuring north velocity (V N ), east velocity (V E ), heading (ψ H ) and rate of change of heading (ψ̇ H ) comprises an inertial reference system.
Claim 11
Dependent Claim
60 words
Apparatus according to claim 9 or 10, wherein the means for determining V CT comprises means for determining the cross heading velocity (V C ) and the heading velocity (V H ) as a function of V N , V E and ψ H and means for determining the integral of V CT from V C and V H .
Claim 12
Dependent Claim
45 words
Apparatus according to claim 11, wherein V C and V H are determined according to the relationships: V C = V E cos ψ H - V N sin ψ H V H = V E sin ψ H + V N cos ψ H
Claim 13
Dependent Claim
23 words
Apparatus according to claim 11 or 12, wherein said means for determining V C and V H uses a velocity computation circuit (16).
Claim 14
Dependent Claim
33 words
Apparatus according to claim 11, 12 or 13, wherein V CT is determined according to the following relationship: V CT = V C - V H sinβ - R L ψ H .
Claim 15
Dependent Claim
23 words
Apparatus according to any one of claims 9 to 14, wherein said means (18) for providing crab angle (β) comprises a first integrator.
Claim 16
Dependent Claim
25 words
Apparatus according to any one of claims 9 to 15, wherein said means (20) for providing lever arm (R L ) comprises a second integrator.
Claim 17
Dependent Claim
46 words
Apparatus according to claim 16 when appended to claim 10, 13 and 15, wherein said means (28, 30, 32, 34) for determining V CT comprises a circuit coupled to said inertial reference system (14), said velocity computation circuit (16), said first integrator and said second integrator.
References Cited (Backward Citations)
No citation records indexed.
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