Optimum Alignment of an Inertial Autonavigator

• Published in: IEEE transactions on aerospace and electronic systems Vol. AES-3; no. 6; pp. 880 - 888
• Main Authors: Jurenka, Frank D., Leondes, Cornelius T.
• Format: Journal Article
• Language: English
• Published: IEEE 01.11.1967
• Subjects: Accelerometer; Accelerometers; Aircraft navigation; Azimuth; Computer errors; control law; Control systems; drift rate; Error correction; error model; gyro; gyrocompassing; inertial system; Instruments; linear filter; Motion control; navigation; Optical sensors; Schuler-tuned system; Velocity control
• ISSN: 0018-9251
• DOI: 10.1109/TAES.1967.5408659

The performance of an inertial autonavigator can only be as good as the accuracy to which the system is initially aligned. Optical methods of alignment can be performed with high precision; however, this technique requires external equipment and is subject to some physical constraints, such as land-based operation. The general problem discussed here is the use of an automatic azimuth alignment technique known as gyrocompassing. In the use of the gyrocompassing technique to obtain azimuth alignment, accuracies are degraded considerably by two dominant error sources, the level axis controlling gyro drift rate and the imperfections of reference or independent velocity information. Consequently, an optimum performance controller is developed for driving the system in this mechanization and is based on a priori knowledge of the second-order statistics of the system error sources. The performance criteria will be to minimize the mean square azimuth error.