The paper focuses on improving the accuracy and shortening the time of shipborne SINS initial alignment under the ship yaw, roll and pitch. This is achieved by implementing a two-step SINS alignment algorithm. At the first step, the ship current attitude parameters are approximately autonomously estimated by data from gyros and accelerometers with account for its dynamics and using water speed log data. At the second step, the system fine alignment is performed with account for alignment errors after the completion of the first step. Speed and position measurements from external aids are additionally applied during the fine alignment. Kalman filter algorithms are used in the first and second steps. Results from bench and sea tests for SINS on navigation grade FOGs under the ship yaw, roll and pitch motion are provided.

A critical functional part of a hemispherical resonator gyroscope (HRG) is the mechanical resonator, and a few million quality factor (Q-factor) is needed for the lowest resolution. This paper focuses on anchor loss of a HRG of a few millimeters in size. A detailed parametric study of dimensions and shell imperfections due to fabrication is carried out. A sensitivity study of the effect of shell mean radius, shell thickness, stem radius, stem height on the Qanchor is carried out. The effect of geometric imperfections such as shell offset, shell tilt, shell thickness variation, and unbalance is studied in detail. From the study, it is inferred that the anchor loss becomes very significant and approaches other loss mechanisms even with minor geometric imperfections in the hardware realisation. Based on the sensitivity study, the dimensional and geometric tolerances are arrived for precision fabrication. Precision resonator is fabricated as per the requirement of minimum anchor loss. The significance of other damping mechanisms such as air damping, excitationinduced damping, thermoelastic dynamic damping and surface dissipation is also discussed. Surface characterisation before and after surface treatment has been carried out using nanoindentation technique with regard to surface loss. Functional parameters of operating frequency and Q-factor are evaluated using laser Doppler vibrometry (LDV).

The paper considers an original autonomous correction algorithm for UAV navigation system based on comparison between terrain images obtained by onboard machine vision system and vector topographic map images. Comparison is performed by calculating the homography of vision system images segmented using the convolutional neural network and the vector map images. The presented results of mathematical and flight experiments confirm the algorithm effectiveness for navigation applications.

The article gives an overview of the methods for determining orientation angles from observations of external reference vectors. To maintain the observability of the kinematic parameters of the free-flying aircraft model motion in a vertical wind tun-nel, we analyzed the methods for determining the finite rotation vector using two, three or more vectors, known in a model body frame, as well as their derivatives. The methods to estimate the reliability of the calculated orientation angles are proposed. The method for estimating the radius of the free-flying model spin is considered.

The objective of this work is to determine the accuracy characteristics of time scale displacement estimates for a transportable quantum frequency standard in motion. The estimates under study have been obtained on the basis of measurements from global navigation satellite systems and inertial navigation system. The results of both separate and joint processing of measurements from two systems are presented. Quantitative estimation of error reduction in determining the time scales displacement has been done by integrating the measurements.

The algorithm presented earlier is updated for the case when an autonomous unmanned vehicle (AUV) is equipped with a strapdown inertial navigation system (SINS) based on angular rate sensors and a water speed log. The algorithm simulation results for a SINS of navigation grade, a two-component water speed log, two trajectories of the AUV motion when approaching the beacon to a distance of 100 m; two values of the AUV’s speed; solid and fragmented diagrams of received acoustic measurements are presented. The results show that the algorithm provides the AUV positioning accuracy of several meters even in the situations when the received acoustic measurements are discontinuous. It has been found that the accuracy characteristics provided by the algorithm adequately reflect the level of real errors.

The article describes the design of passive underwater landmarks (PUL) and their use for navigation of autonomous unmanned underwater vehicles (AUV). The procedure of AUV observation using PUL is considered. It is shown that with proper maneuvering of the AUV during observation, the accuracy of determining its coordinates is limited only by the accuracy of the PUL positioning during installation. This accuracy also affects the distance between neighboring PULs installed along the AUV’s route. If the AUV is equipped with a high-precision autonomous navigation system, the PULs can be installed at the intervals of several hundred kilometers.

Algorithms for a dispatcher of a multi-agent control system for an autonomous underwater vehicle (AUV) are described. The algorithms are designed on a modular basis, which provides for the control of a wide range of tasks assigned to the AUV, and, in addition, makes the implementation of each algorithm simple.

The paper presents the history of creation and development of Ladoga-M marine inertial navigation and stabilization system (INSS). The major steps of testing and modifications are covered. The system architecture and key features are given: semianalytical inertial navigation system, rotation of azimuth platform, single degree of freedom floating gyros, accelerometer triad, application of Kalman type filter, use of Baget computer. INSS reliability parameters by the results of operation in real conditions are demonstrated.