Rapid Initialization of Inertial Navigation Systems Through Parameter Estimation

摘要

The accuracy of an aircraft inertial navigation system depends upon the accuracy with which the system is initially aligned. One procedure for initial alignment involves the use of an external reference. This method utilizes equipment which is much too elaborate for normal operational use. An alternate procedure uses the system's inertial sensors in a self-contained method. If sufficient time were available, the self-contained method could achieve accuracies commensurate with the sensor accuracies; however, in an operational environment it is usually necessary to sacrifice some accuracy in the interest of achieving a more rapid initiation. This dissertation investigates the methods presently available for initialization of an inertial platform in an azimuth wander or free azimuth instrumentation and presents a new method for rapid initialization. The paramount problem is the determination of the initial azimuth angle in minimum time in the presence of random gyro drifts, random accelerometer drifts, and measurement noise. (Author)