Allan variance was originally introduced as a characteristic for time and frequency standards, and now it is widely used in many fields, including the construction of navigation devices. The paper presents an outline of Allan variance applications in various tasks, including the estimation of characteristics of navigation devices. Nevertheless, there are some cases when the efficiency of Allan variance is insufficient, and its physical interpretation appears to be vague. It seems to be associated with purely empirical origin of this characteristic, as the initial scale parameter has not been defined yet. Statistical interpretation of the Allan variance is proposed in the paper. It is based on the model of random processes with stationary increments, which includes both stationary and Wiener processes. Structure function is the main scale parameter in this model, and Allan variance is an empirical estimate of this parameter. This representation clarifies the statistical meaning of Allan variance, and it also explains high efficiency of Allan variance for non-stationary signals and noises. Thus, Allan variance is a general characteristic which describes the stability of the measurement and navigation devices.

The paper considers the specific features of feedback circuit implementation in an angular rate quantum sensor based on a two-frequency spin oscillator on xenon isotopes. Technical solutions which ensure stable two-frequency oscillation, such as automatic gain control units and phase filters, are listed. The results of experimental studies of oscillation modes on breadboard angular rate quantum sensor with stationary and rotating base are presented.

The paper discusses the specific features of tuning and calibration of a hemispherical resonator gyroscope (HRG) with a metal resonator for the angular rate sensor (ARS) mode. Since the output signal contains the Coriolis and quadrature components, the compensating signal in the feedback loop is formed on the basis of two-stage correction algorithm. The results of the HRG-ARS testing using an electronic unit with the two-stage correction functions are presented.

Global Navigation Satellite System (GNSS) software-defined radio (SDR) is a programmable software receiver, primarily used to receive satellite data and provide user position. It is flexible and cost-effective compared to conventional satellite receivers. In GNSS SDR, recording the live raw data in real-time is a challenging task as large data are sent by the satellites at a very high speed. These data are further processed by the baseband algorithms which provide the user location. The accuracy of the tracked location depends on the precision of the data captured. Among the available hardware receivers, USRP RF front end kit provides flexibility. This paper proposes an efficient approach to capture the real-time GPS data by using the USRP N210 kit. If the receiver is not tuned with the exact parameters, the problems of data overflow and underflow occur. A novel data controlling queue thread method is introduced to overcome this problem. It is evident that the results obtained from our method are very close to those of u-blox GPS.

The results of a comparative analysis of methods for positioning and timing support of remote users based on GNSS measurements from a GLONASS receiver and observational data on quasar radiation from compact very long base radio interferometric (VLBI) systems are discussed. Using radio telescope measurements increases the stability of positioning-and-timing and navigation support of users owing to observations of radiofrequency radiation emitted by the sources of natural origin. The approach proposed in this paper focuses on using radio interferometry for precision positioning and timing of remote radio telescopes. This method can be helpful for specific applications relevant to positioning and timing support for remote users with an arbitrary positioning topology.

Unmanned aerial vehicle (UAV) is a complex system. Its design involves control, aerodynamics, and communication systems. We use the complex linear relationships among UAV attributes (sensor readings, and commands) to propose a new technique to detect contextual faults. The contextual faults mean that a defective sensor shows invalid values concerning the context of other attributes. The proposed approach depends on estimating the values of a focused attribute using dynamic linear regression. Next, it calculates the estimation error at each time step. The values of the estimation error are classified using K-NN (Nearest Neighbour) classifier into two classes (Normal, Abnormal). The abnormal points are flagged as potential faults. Moreover, comparison with other algorithms (K-Means and One-Class SVM) is made. The proposed approach showed better results in most of the cases.

Probabilistic study of angular motion dynamics has been performed for CubeSat nanosatellites with passive stabilization systems, including aerodynamic, aerodynamicgravitational, gravitational, and gravitational-aerodynamic ones. Analytical functions of the maximum angle values distribution have been obtained for a nanosatellite axes deviation from required directions (orbital velocity vector or a local vertical) for uniform distribution and Rayleigh distribution of the component values of the initial angular rate vector. Formulas have been derived and bunch graphs have been plotted for selecting the design parameters (geometrical dimensions, static stability margin, moments of inertia) which ensure the required attitude with the specified probability in circular orbits.

The paper presents brief information on the results of research and development activities undertaken in 2015–2019 and aimed at the practical implementation of e-Navigation concept. Current state of practical application of S-mode, the only global product created within the concept, is studied. Most of the new technologies developed under the main regional projects are discussed. Special focus is made on the situation with e-Navigation in Russia.