Initial Alignment of SINS Measuring Unit and Estimation of Its Errors Using Satellite Phase Measurements

Abstract

The paper addresses the problem of initial alignment and periodical estimation of gyro drifts and accelerometer errors in a strapdown inertial navigation system (SINS) on fiber-optic gyros (FOG) of navigation grade onboard a marine vehicle, using satellite phase measurements from multi-antenna equipment. The problem is solved through constructing a tightly-coupled INS/GNSS system which comprises an inertial measuring unit (IMU) of SINS, and a multi-antenna satellite module. The satellite module has two antenna baselines and employs receivers with a common reference oscillator. Based on the SINS data, the ambiguity of phase measurements is excluded, and false measurements are sorted out. The results of joint processing of the bench test data for the navigation grade FOG-based IMU (designed by Concern CSRI Elektropribor, JSC) and a virtual simulated satellite module are presented. The data processing was carried out using the algorithms of integrated system construction in MATLAB (Simulink) package.