Strapped-Down Inertial Navigation System Algorithm’s Perfection Partially Using Sensors

E.V. Karshackov, V.V. Tikhomirov

Control and Navigation Laboratory

Faculty of Mechanics and Mathematics, Moscow State University

119899, Moscow, RUSSIA

tel. (095) 939-59-33

e-mail: karshack@mech.math.msu.su

V.A. Yakovlev

Moscow Experiment and Design Bureau “Mars”

16, 1^st Schemilovskiy side str., 103030, Moscow, RUSSIA

tel. (095) 978-09-50

The problem of Strapped-Down Inertial Navigation System (SINS) algorithm's perfection partially using real sensors appeared during designing of such a system based on the Optical Fibrous Gyroscopes (OFG). The angular velocity sensor (AVS) was used as one of sensors. It was the Optical Fibrous Gyroscope DUS-500 produced by Perm Scientific-Industrial Instrument Making Company and granted to Moscow Experiment and Design Bureau (MEDB) “Mars” for the purpose of design of SINS. DUS-500 is the functionally complete instrument with RS-232-code output information. Thus one is able to connect this sensor to the COM-Port of a Personal Computer.

The most important advantages of OFG are the absence of mechanical rotation of its parts, that provides instrument long life, wide range of measuring angular velocities: from hundredth of deg/hour to hundreds of deg/sec, with high precision of scale coefficient. The output signal is the increment of angle during tact (0.01024 sec) given by the number of impulses. The measure of one impulse is 0,25 ang. sec. Perm Company is not producing industrially the sensors, one of which was granted.

Another Scientific-Research Company “Fizoptika” is also widely known as the enterprise, that produces the Optical Fibrous Gyroscopes in Russia. It produces the gyroscopes of different classes – their bias variation is from 0.5 (Fiber Optic Rotation Sensor VG951) to 50 degrees per second. Besides, the scale coefficient stability for the constant temperature is 0,1% for VG951. Using of such gyroscopes for the autonomic navigation devices design is impossible. Nevertheless, they are used for the integrated systems production. These systems contain both with the inertial navigation block the GPS receiver. Such systems are produced by Scientific-Research Institute “Electropribor” in St. Petersburg [1]. But it is necessary to find another correction information, because the satellite navigation systems can not be used for the transporting of the satellite to the high orbits.

MEDB “Mars” is designing the inertial navigation system with correction too. Note, that DUS-500 has the feedback, that provides the essential improvement of the scale coefficient stability.

The experiments were performed in June – November in 1999 by MEDB “Mars”.

The methodic for the Strapped-Down Inertial Navigation System algorithm’s perfection and estimation of the parameters of some sensors used for design of such systems was created during the described experiments.

Even an incomplete number of real sensors made it possible to reveal in dynamics the SINS errors generated by the sensors errors and initial data inaccuracy.