The Research Of Rotation-modulation Strapdown Inertial Navigation System By Optical Gyros

Inertial measurement units (gyroscopes and accelerometers) are fixed directly to thecarrier in strapdown inertial navigation system, which simplifies the system hardware toimprove the reliability of the system. By the advantages of its small size, low cost, easymaintenance, comprehensive ability and many other outstanding advantages, SINS has almostreplaced the PINS. With the domestic optics, measurement and control technology in furtherimproving, the core of optical components gyroscope SINS is playing an increasinglyimportant role in the area of inertial technology applications.With the influence from precision of inertial measuring unit and working condition, theprecision of SINS is lower than that of PINS. And because the error of the inertial device isthe main source of error in SINS, that can effectively inhibit the inertial device error hasbecome the key to improve the SINS accuracy.The two measures can improve the accuracy of SINS: one is to design and create morehigh-precision inertial components; another one is the adoption of systems technology.Relative to the high costs for improving the accuracy of inertial components, it is easy toachieve low cost advantage by using system technology for the purpose of improvingnavigation accuracy. Rotation modulation is a method of automatic correction.In the purpose of improving the precision of SINS by optical gyros, the basic principlesof rotary SINS was analyzed firstly. Then the drift, scale factor and fixed error was analyzed.Through the analysis for the rotary SINS of the error characteristics, the system error analyticunder the gyro drift and scale factor error conditions was derived. On this basis proposed, amethod to determine the rotation rate was advanced. And the system simulation verifies thefeasibility of the method. It was summarized to meet a reasonable rotation of three conditions.Through the analysis of three single-axis rotation program, a new single-axis rotation programwas designed. With a comprehensive comparison of the inhibitory effect of the program andthe system simulation, the effectiveness of the program was verified. At last the projectvalidation experiments have been designed, which used to test different options for therotation inhibitory effect of navigation parameter error and verify the new single-axis rotation.Through the theoretical analysis, system simulation and rotating–platform experiments,the rotation modulation techniques has been proved to improve the precision of the opticalgyroscope SINS.