FAULT-TOLERANT INERTIAL NAVIGATION SYSTEM
 Inventor: James R. Huddle, Chatsworth, Calif.
 Assignee: Litton Systems, Inc., Beverly Hills, Calif.
 Appl. No.: 692,348
 Filed: Apr. 26,1991
 Int. Cl.s G06F 15/50
 U.S. CI 364/453; 33/321
 Field of Search 364/453, 560, 131, 184;
33/318, 321; 318/564
 References Cited
U.S. PATENT DOCUMENTS
3,489,004 1/1970 Barnhill 73/178
3,680.355 8/1972 Goldstein 73/1 E
4,173.784 11/1979 Heath et al 364/453
4,425,040 1/1984 Ljung 356/350
4,914,598 4/1990 Krogmann et al 364/453
5,012.424 4/1991 Dodson 364/453
5,050,087 9/1991 Walrath et al 364/453
Chapter 11-Application Of Kalman Filtering Theory
To Augmented Inertial Navigation Systems; Dr. J. R.
Huddle; Article of Litton's Guidance & Control Sys-
tems Division (Feb. 1970) pp. 233-268.
A New Mathematical Formulation for Strapdown Iner-
Disclosed herein is a Fault-Tolerant Inertial Navigation System comprising, in a preferred embodiment, a Redundant Set of at least two Inertial Navigation Systems, from which one may identify and isolate at least one instrument within an Inertial Navigation Unit which shows substantial performance degradation. The two inertial navigation units are fully capable of performing navigational functions. Each of these inertial navigation units has a plurality of navigational instruments, including at least three linear sensors (such as accelerometers) and three angular change sensors (such as gyroscopes or ring laser gyroscopes). No two linear sensors nor any two angular change sensors of either unit are aligned colinearly. Each of the inertial navigation units produces a set of independent navigational solutions at each of their respective outputs. The independent navigational solutions of each of the navigation units are compared and any significantly degraded performance of any one linear sensor or any one angular change sensor is detected.
8 Claims, 4 Drawing Sheets