Algorithmic support of low-altitude aircraft flight based on the hazard analysis of the flight situation

Low-altitude flight of an aircraft is an effective, but at the same time, a very complex tactical technique, during which the crew does not always have the opportunity to timely recognize the occurrence of an abnormal case, determine the way out of it and counteract an aviation accident development. Despite many advantages of the automatic mode of low-altitude flight performing, its practical implementation is associated with a number of features and disadvantages, which determined the preference for the manual mode of low-altitude flight control. These are the presence of telltale factors, limited ability of performing flights at night and in difficult weather conditions, insufficient reliability etc. The considered features determined the relevance of the of low-altitude flight safety ensuring problem in relation to the manual control mode. As a result of an experimental study of the low-altitude flight performing process in a manual control mode, it was found that when performing manually-controlled low-altitude flight, a hazard assessment of the flight situation becomes pivotal. However the crew being under such conditions is not always able to correctly assess the flight situation hazard due to a combination of objective reasons. The current state of the adaptive and on-board flight safety systems theory makes it possible to increase the safety of the manuallycontrolled low-altitude flight by using adaptive control algorithms based on the flight situation hazard assessment. To solve this problem an adaptive control algorithm is proposed that ensures the formation of a security corridor in the longitudinal control channel, where the upper limit is determined by the critical value of the aircraft detection hazard, and the lower limit is determined by the critical value of the error in maintaining a given flight altitude. For a continuous assessment of the flight situation hazard and the timely formation of control signals the complex information about the current true flight altitude and the foreground is needed. Taking into account the peculiarities of low-altitude flight a digital terrain map containing data on natural and artificial obstacles along the flight route is a more rational source of information, that will make it possible to predict the development of the flight situation hazard. The above reasoning makes it possible to form an aircraft low-altitude flight adaptive control algorithm. A distinctive feature of the proposed algorithm is the implementation of a combined control variety where the pilot is provided with ample manual control opportunities within the security corridor, and the automatic flight control system is assigned the role of a safety subsystem that ensures control and timely return of the flight situation to normal flight conditions. The presented algorithm will allow to increase the crew logical-analytical activity information support during continuous analysis of the existing flight situation due to the formation of protective control actions based on the current flight situation hazard analysis.

Ensuring the secrecy of the radar

The article deals with the issue of stealth of radio-electronic means, energy and structural, radio-electronic masking and ways of its implementation. The structure of the unknown signal for exploration and its parameters, as well as the a posteriori probability of each signal associated with the a priori likelihood function and the cases of its solution. The advantages and disadvantages of broadband signals and their characteristics used in modern radars are considered. On the basis of which conclusions are drawn: LFM radio pulse and a single FCM pulse, used in target tracking modes, has high resolution capabilities in range and radial velocity. The ACF of the FCM pulse has side lobes that raise the target detection threshold, as a result of which radar targets with a weak echo signal can be missed. The considered signals do not provide energy and structural stealth of the radar operation.

Method for building a model of the functioning of the on-board equipment of spacecrafts based on a classification scheme of interactions of subsystems

In this paper, a promising approach to solving the problem of adaptive-distributed control of the technical condition of onboard equipment of spacecraft based on the classification scheme of the mutual influence of subsystems is determined. Purpose is to improve the efficiency of autonomous monitoring of the technical condition of spacecraft on-board equipment. The proposed method for constructing a model of the functioning of onboard equipment of spacecraft made it possible to obtain a classification scheme for the mutual influence of subsystems of onboard equipment, the use of which as a vehicle control model provides semantic compression of telemetric information. The idea of creating a special software for advanced on-board control systems with the function of adaptive-distributed control of technical condition is proposed. The possibility of using the methodology is not excluded when constructing a model of the operation process of on-board equipment for objects of various purposes, including as an element of an artificial intelligence system when solving the problem of monitoring a technical condition.

Structural-parametric synthesis of the tracking filter based on decomposition by the target functional with adaptation to trajectory disturbances

Traditional Kalman-type tracking filters are based on a kinematic motion model, which leads to the occurrence of dynamic errors, which significantly increase during target maneuvering. One of the solutions to this problem is to develop a model of motion dynamics with the ability to adapt its structure to external influences. It is shown that the use of a dynamic model of motion in the filter, which takes into account the inertia of the target and the forces acting on it, makes it possible to significantly increase the efficiency of the state assessment. Purpose is to development of an algorithm for assessing the position of a maneuvering object, effective in terms of accuracy criterion. The use of an adaptive motion model as part of the filter provides an increase in the estimation accuracy in comparison with the classical Kalman filter, which is confirmed by the performed numerical modeling.

Model of the functioning of the optoelectronic information system for detecting space debris

To determine the characteristics of optoelectronic devices, as a rule, models are used that do not take into account the peculiarities of the functioning of information tools, the conditions of visibility and observability, which does not allow to reliably assess their capabilities to obtain coordinate and non-coordinate information. Goal of the work is to investigate the model of an optical-electronic information tool in order to evaluate the characteristics and determine the possibility of obtaining coordinate and non-coordinate information in various conditions. A block model of a system for monitoring space debris in near-earth space by means of optical-electronic information means is considered. A structural diagram of the model's constituent parts is proposed. It is shown that the position of an object in the composition of space debris is determined based on the solution of the above differential equations. The interrelation of the influence of various conditions on the capabilities of optoelectronic information facilities, on the processes of detection and tracking is described. The equations and relationships underlying the model of operation of the optoelectronic information facility are described. The results of modeling are presented, which allow planning the rational placement of optoelectronic information facilities. The presented model makes it possible to obtain initial data for planning the rational placement of optoelectronic information facilities and to substantiate the requirements for their technical characteristics.

Substantiation of selection and dimension reduction of non-centered informative features of signals in information systems of short-range location

In this paper, we consider the issues of selection of informative features, dimension reduction of feature vectors in regression algorithms of detection and recognition of signals and interference, as well as the issues of obtaining informative features using neural network algorithms with ill-conditioned data. The problem is considered in relation to the short-range location, with large dynamic ranges of informative features and small decision intervals, when it is impossible to estimate mathematical expectations, that is, it is impossible to use adaptive algorithms. Regression algorithms for processing non-centered random signals are presented, with a priori unknown mathematical expectations of informative parameters, which consider the specificity of short-range location and use a priori information about the initial regression characteristics of informative features – multiple initial regression coefficients. Unlike it is in traditional regression analysis, the coefficients are determined through the elements of the matrices that are inverse to the matrices of the initial correlation moments. In regression algorithms, it is necessary to calculate the square error of multiple initial regression representations. The residual mean of squares of the initial regression representations are used to justify the methods for selection and dimension reduction of informative features of signals in the problems of detection and recognition of signals and interference. We give examples of application of the proposed methods for the problems of detection and recognition of a helicopter and airplane by acoustic signals when processing histograms of the distributions of the durations of intervals between zeros, samples of envelopes and samples of local extrema of the power spectral density. Good separability of the {airplane} and {helicopter} classes in the space of non-centered parameters of signals (features) is shown. The issue of obtaining regression statistical characteristics with illconditioned data is considered. If the matrices of the correlation moments of the informative features of signals and noise are illconditioned, it becomes impossible to obtain a priori information about the multiple initial regression coefficients. The possibility of using neural network algorithms to obtain estimates of the residual mean squares of regression representations and multiple initial regression coefficients through the weight coefficients on the inputs of neurons with ill-conditioned data is shown. The results can be used in short-range location systems with a large dynamic range of non-centered informative parameters, when it is not possible to estimate the mathematical expectations of the signal parameters due to the limited observation interval.

Peculiarities of making decisions on the choice of the composition of the main hardware equipment of aviation multifunctional simulators

The current stage of training aircraft crews (AC) is characterized by the predominance of training tasks solved with the help of aviation multifunctional simulators (AMT). AMT covers a wide range of aviation simulators designed to solve problems of planning and managing the use of hardware and software resources in solving various training tasks in the interests of training aircraft crews. Based on this, AMT are characterized by a variety of hardware that ensure the implementation of technological operations and processes for analyzing and processing information when performing educational tasks, which determined the relevance of the task of choosing their optimal composition. Purpose of the work is to develop a model for choosing the composition of hardware equipment (HSS) in the AMT structure for solving training tasks in the interests of training aircraft crews. The solution to the optimization problem of substantiating the CAO is based on the analysis of the features of the application and development of AMT based on the modernization of obsolete and new hardware equipment. The complexity of the task is due to significant computational difficulties arising from the need to provide various technological operations and cycles of information flows in the form of a certain set of elementary operations and the presence of “individual” quality criteria for each educational task. To solve it, the technological process of solving educational AMT is represented by an oriented graph, the vertices of which are the tasks to be solved, and the arcs connecting them are elementary technological operations implemented by hardware. The fulfillment of each educational task is based on the fulfillment of a certain set of elementary streams based on the implementation of the compared CAO options in the AMT structure. The search for a solution is carried out on the graph using a three-level model based on finding optimal solutions to cover the educational tasks to be solved with the available means of obsolete hardware equipment, justifying the required number of new (developed) tools and choosing their optimal composition in the AMT structure as a whole, taking into account the preferences of the persons taking decision (decision maker). The proposed methodological approach and the model for choosing the CAO that implements it provide a sequential and level-bylevel solution of optimization problems with extreme variables for a reasonable choice of the decision maker of the optimal composition of hardware in the AMT structure in the interests of solving a variety of diverse training tasks for training aircraft crews.

A mathematical model of the functional reliability of radio electronic means, taking into account their predicted technical condition

The requirement for the adaptability of mathematical models of systems for processing technical information and functionality (SOTIF) of radio electronic means (RES) should be understood as the need to take into account the main features of the RES in the system model, as well as the complexity (a large number of elements, multi-mode, etc.) and a significant difference in elements RES by the nature of the degradation processes occurring in them, manifested in the differences in their probabilistic characteristics of reliability. The mathematical model of SOTIF RES should take into account the fact that, on the one hand, the real properties of the reliability of the RES may change in the process of targeted use under the influence of external factors, and on the other hand, the available information on the reliability of the RES is always incomplete and inaccurate. Therefore, it is necessary that the mathematical model of the system provides for the possibility of entering additional (a posteriori) information and recalculating the previously found optimal terms and volumes of technical impacts. Goal of the work is to form a reflective model of the change in the state of the RES with the features and at the same time the difficulties of the need to use the composition of the distribution laws, including the a priori and empirical (a posteriori) components. An approach is proposed, according to which, as elements of the REM sample, parts of the equipment are distinguished, which are covered by the influence of given preventive operations. The distribution laws of the operating time to failure of the selected elements can be specified by any functions corresponding to increasing (or increasing on average) functions of the failure rates. In the developed model, the empirical component, in turn, includes two components due to structural and parametric failures (structural and parametric components). A mathematical model of the functional reliability of the RES has been developed and the information-significant characteristics of the reliability of the RES have been demonstrated.

Method for synthesis of information-learning systems (simulator) troubleshooting in radio-electronic objects

Complication and fault tolerance of the equipment of complex radio-electronic objects (REO), incomplete coverage by means of internal diagnostic control of possible failures, the absence or presentation by the developers of diagnostic charts of troubleshooting in a tabular form, as well as the considerable remoteness of stationary points for carrying out control and diagnostic operations on them determined the prerequisites for the development of information and training systems (IOS) or simulators. The purpose of their development is to increase the efficiency of troubleshooting the equipment of electronic equipment in the places of their operation and the direct training of maintenance specialists. The IOS development method represents a system of approaches, principles, mathematical methods, models and techniques united by the unity of purpose for determining the laws of transformation of input information and justification based on the results obtained in terms of the maximum likelihood of trainees fulfilling the assigned tasks of troubleshooting in the electronic equipment for its optimal appearance (composition, technical characteristics and algorithms of functioning). In this case, the appearance of an IOS is structurally presented as a hierarchical system of functional elements for modeling parts (in the form of subsystems, complexes), components (means), functional blocks, boards and nodes of a specific REO, which are software equivalents of its control systems, information support and execution. The basis of the IOS synthesis is formed by the results of the analysis of a priori information on faults in the structure of complex electronic equipment. Using the methods of hierarchical decomposition and invariant immersion, a fault tree is formed in the structure of the REO at the levels of parts, components and functional blocks, boards and nodes. It is carried out on the basis of the sign of recognition of inhomogeneity (faults differ in time), eccentricity (the occurrence of several faults at the same time) and nonstationarity (various changes in the fault flow density are possible) of faults, their classification into elementary, group and multiple, which allows the method of systematic cover to form options for the structural and functional appearance of the IOS. The search for a solution is based on the use of graph theory, dynamic programming methods, branches and boundaries to substantiate the optimal (shortest) troubleshooting path by representing the elements of the REO structure in the IOS in the form of graph vertices and links (in the form of arcs) between them, identifying inherent in this level one or another malfunction. Information about faults in the IOS is formed on the basis of analysis, justification and optimization of troubleshooting functions using builtin diagnostic control points formed by a set of diagnostic tools built into the hardware and additional diagnostic control points (dialogue), decisions about faults in which are made in semi-automatic mode or manually trainees using general purpose test equipment. The search for the optimal solution is carried out on the basis of the formation of the region of feasible solutions formed on the Euler-Venn diagram in the form of the intersection of the troubleshooting functions and justification by the maximum element method of the optimal solution to eliminate the identified faults. The implementation of the method makes it possible to solve a complex multi-parameter optimization problem of troubleshooting in complex REO of a given subject area and to justify the requirements for the appearance of an IOS when developing a technical task for its development.

Methodology for estimating the efficiency of optical-electronic systems using an analytical model. Functions of threshold contrast and modulation transfer

Efficiency assessment is an integral part of the stages of development, testing and operation of optoelectronic systems. The lack of a unified methodology for assessing the effectiveness of optoelectronic systems leads to the fact that different assessment methods are used to compare different systems, as a result of which the results obtained are contradictory and do not provide objective data for making appropriate decisions at various stages of the life cycle of optoelectronic systems. One of the ways to solve this problem is the development of an analytical model, which can be the basis for the construction of a unified set of intellectual support for the design and maintenance of optical-electronic systems at all stages of the life cycle. The aim of the study is to form an analytical model for evaluating the effectiveness of optoelectronic systems, in terms of the functions of threshold contrast and modulation transfer. As a result, the analysis of models for evaluating the efficiency of the optoelectronic systems NVL 1975, FLIR92, NVTerm, NVTermIP and NV-IPM was carried out, and the main differences between these models were considered. The functions of the threshold system contrast and the threshold contrast of the human visual system are considered. The effect on the form of the threshold contrast function of the modulation transfer function (frequency-contrast characteristic) of the system and the external environment, as well as space-time noise, is shown. Then, a description is given of the components of the modulation transfer function of the system and the environment: the modulation transfer function of the turbulence of the atmosphere, the transfer function of the motion modulation of the optoelectronic system, the modulation transfer function of the optical system, the detector modulation transfer function; image processing modulation transmission functions. Monitor modulation transfer functions. The main parameters of the modulation transfer function, which are used to estimate the resolution of the optoelectronic system, are considered. Examples of evaluating the resolving power of various optoelectronic systems are given and the effect of smearing caused by the movement of the carrier of the optoelectronic system on the image quality for different values of exposure time is shown. The practical significance lies in the fact that the research results were applied in the development of tactical and technical requirements for optoelectronic systems, in the development of optoelectronic systems at the stages of preliminary and technical design, showed the consistency of the calculation results with the results of using existing systems.