Vol 10, No 2 (2019)

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.

This paper presents a modified adaptive analytical algorithm for attitude and heading estimation. The analytical algorithm is based on the fusion of IMU, magnetometers and the velocity data from GPS. The kinematic Euler angles are first calculated based on the output of the rate gyros, then the calculated angle errors are compensated using the output of each of the accelerometers, magnetometers, and the velocity taken from a GPS receiver, without the need to model the systematic and random errors of the used sensors; Kalman filter is not used. The algorithm will be adaptive based on the maneuver classification, the filters’ parameters will be tuned depending on the maneuver intensity: No, Low, or High maneuver. The main contribution of this paper is to build an attitude and heading estimation algorithm (analytical algorithm) without using Kalman filter; this algorithm will be made adaptive based on the maneuver classification algorithm which was developed using logistic regression technique based on IMU output. Computer simulation with simulated and real flight data showed that the adaptive analytical algorithm has acceptable results compared to EKF.

Position, velocity, and timing (PVT) signals from the Global Positioning System (GPS) are used throughout the world but the availability and reliability of these signals in all environments has become a subject of concern for both civilian and military applications. This presentation summarizes recent advances in navigation sensor technology, including GPS, inertial, and other navigation aids that address these concerns. Also addressed are developments in sensor integration technology with several examples described, including the Bluefin-21 system mechanization.