Research On Error Modulating Technology Of Strap-down Inertial Navigation System

Error modulating technology is a very advanced system technology via that technology the precision of inertial system can be increased with limited cost increase, so it has been a key issue to scholars at home and abroad. Inertial navigation system used error modulating technology is named rotating inertial navigation system. In this paper, the strap-down inertial navigation system is taken as background, mainly analysis the error source of single axis rotating system, then single axis rotating schemes are given.First, the basic theory of strap-down inertial navigation system (SINS) is given and error modulating technology is summarized. The essence of error modulating technology is explained from mathematical equation of SINS. In the ideal condition, namely only exists gyro drift and accelerator zero bias, the basic principle of error modulating for single axis rotating system is analyzed.Next, the error source of rotating SINS is analyzed. There are only const drift error exist on inertial apparatus under ideal condition, but in the real system, there are rotating axis'condition, the calibration error of inertial apparatus and the precision of rotating institution exist. In this paper, the influence of these error factors to the rotating SINS is analyzed.Again, on the basal analysis above, and considering practicability on engineering, two simple single axis rotating modulating schemes are given. Totally analysis is taken out on influence for attitude, velocity and position of inertial system caused by coast drift error of inertial apparatus, calibration error and installation error. The validity of analysis above is verified via simulation.Finally, engineering verification is designed according to the theory analysis. We use a medium precision fiber-optic gyroscope strapdown system developed by our lab and a high precision three axis table to do a principle experiment. The experiment results of static experiment and rotating experiment are contrasted, and the experiment conclusion is given.