The limitations of Kalman filter (KF) have motivated researchers to consider alternative methods of integrating inertial navigation systems (INS) and global navigation satellite systems (GNSS), predominantly based on artificial intelligence (AI). Over the past two decades, a great number of research gained in order to validate the possibility of using AI methods in the field of integrated navigation systems. Different approaches have been proposed for combining AI modules with the other parts of the INS/GNSS system. The article suggests a new classification of the resulting schemes based on the functionality of AI modules in the INS/GNSS system. The paper also provides a brief explanation of each scheme with its advantages and disadvantages. Some aspects that need to be considered in future research in this field are also highlighted.

Vision-based navigation has been of interest in aviation for decades. Driven by the demand for optical verification of take-off and landing procedures during all-weather operation many developments have been raised following changes in technology of sensor and processing hardware and aviation requirements. This paper summarizes the developments from the 60s until today and exemplarily discusses aspects of vision-based augmentation and integrity monitoring of Integrated Navigation Systems (INS). The main focus lies on vision-aided integrity monitoring during final approach and landing of aircraft.

In this paper, the problem of an autonomous unmanned aerial vehicle (UAV) approach to a target which is selected in a reference image is addressed. A robust matching algorithm is proposed to reliably project the selected point in the reference image into the live images of a quadrotor helicopter. Projective transformations are applied to the reference image to extract additional keypoints and to gain invariance to out-of-plane perspective transformations. Since the matching algorithm does not exploit the beneficial characteristics of image sequences and because its processing time is not short enough for high frame rates, a tracking algorithm is introduced. High detection rates even for image sequences with large viewpoint changes are achieved. Therefore, the presented algorithm can be used as input to a guidance algorithm for UAVs.

The dynamics of onboard gravity gradiometers for measuring the second derivatives of geopotential is discussed in the paper. The mathematical models of accelerometer-type and dumbbell-type devices are constructed, and their instrumental errors are analyzed. Numerical estimates of design specifications are obtained, and it is noted that adjustment and calibration should be performed to ensure measurement accuracy.

The paper considers the methodological aspects of calibration of a 3-axis gyroscope unit on a two-axis calibration turntable with a thermal chamber. For the instrumental errors of angular rate sensor (ARS) measurements, an a priori parametric model is introduced, which includes bias, scale factor errors, small angles of sensitive axes nonorthogonality, as well as the coefficients of temperature variations for all the above measurement errors. The problem of parameters identification for the parametric model consists in the optimal estimation of the state vector of linear dynamic system, based on the vector of measurements linearly linked with the state vector. In such a statement, the vector of measurements is the vector of small turn between the simulated (calculated by the ARS readings) attitude of the unit and the simulated (calculated by the turntable measurements) attitude of the base plate. The proposed approach to the calibration problem formal characterization is a modification of the method of inertial measurement unit calibration, previously developed at the Lomonosov Moscow State University’s Laboratory of Control and Navigation. The method allows for assembled units calibration on low-grade one-axis turntables with horizontal axis of rotation. The calibration experiment is a sequence of horizontal rotations about each of the sensitive axes of ARS. The paper presents the results of numerical modeling and covariance analysis.

A new algorithm and a method of coordinate referencing of a un-manned autonomous underwater vehicle (AUV) to underwater objects using stereo images are proposed for automated inspection of bottom industrial in-frastructure facilities. Computational experiments have been carried out using a modeling simulator based on a hybrid multiprocessor computing architecture. The proposed solutions have been estimated in terms of efficiency.

The paper considers the possibility of direction finding and determining the coordinates of a source of acoustic signal emitted by a surface or underwater moving object in the infrasonic frequency range. For this purpose, combined hydroacoustic receivers are used. In the first experiment, the estimates of the systematic component of the bearing error were obtained for a source emitting a tonal or polyharmonic signal, and the procedure of averaging the direction finding results over a set of frequencies was carried out. The obtained results were used in the second experiment to estimate the error of coordinates determined for a polyharmonic emitter consisting of three combined receivers which form a navigation base distributed in the horizontal plane.

The paper describes the experience of constructing an integrated INS/GNSS navigation system for supporting a radar with a synthesized side-view aperture, located aboard a small-sized unmanned aerial vehicle (UAV). Key features and factors that should be taken into account when developing a navigation system operated under severe conditions are studied. Flight test results are presented, including the estimates of MEMS-based micronavigation system accuracy. The analysis is based on the radio signals reflected from angle reflectors, as well as radar images obtained by constructing a matched filter based on the micronavigation system data.

The paper analyzes the obtained theoretical characteristics of codeless acquisition of GPS signals in L1 band. The presented results make it possible to adequately select an interval of coherent integration, to calculate the detection thresholds and to estimate its probability. The efficiency and applicability of the method of frequency-based codeless acquisition of navigation signals have been experimentally confirmed using a programmed receiver.

The paper presents the basic steps of developing gravimeters for measuring gravity from the mobile vehicle board; the gravimeters are designed by CSRI Elektropribor. Technical solutions are described, which allowed high accuracy of measurements to be achieved. The authors discuss the topical spheres of mobile gravimeter application.