Integrated guidance and control for solar sail station-keeping with optical degradation

Current control approaches for solar sail station-keeping on libration point orbits have not considered the degradation of the sail’s optical properties. However, significant optical degradation could lead to poor station-keeping performance or even complete failure. This paper presents an integrated guidance and control strategy to address this problem by updating the reference orbit based on in situ estimation. An exponential optical degradation model is incorporated into the solar radiation acceleration model, and an on-line reference orbit update approach is incorporated into the station-keeping, coupled with an active disturbance rejection controller. The reflection coefficient is estimated on-line and the reference orbit is updated discretely when the optical properties have degraded by a prescribed amount. This strategy provides discrete updates to the reference orbits such that the perturbation due to the optical degradation is maintained within a small range. These smaller perturbations can be dealt with by the controller’s robustness and station-keeping can be sustained for long durations even in the presence of large optical degradation.     

Parabolic convective motion of a fluid cooled from below with the heat exchange at the free boundary

In the present study, convective motion of an incompressible viscous fluid in the geometrically anisotropic zone with the lower boundary cooled by a localized point source is considered. The existence of closed isolines for the pressure, counter-current flows in the fluid and localization of thermal layer near the free surface is shown.     

Cooperative processing of measurements in multilateral radial–range difference system of passive radiolocation

A study is made to define a procedure of cooperative processing of goniometric and range difference measurements in multilateral system of passive radiolocation. As a result, we worked out the computational algorithms, which implement this procedure. The accuracy characteristics are estimated.     

Influence of combustion chamber geometry and compression ratio on the main parameters of a diesel aircraft engine

This paper considers the problem of increasing the fuel efficiency of a diesel aircraft engine and decreasing the smokiness of its exhaust gases (EG) by means of the experimental determination of optimum compression ratio and combustion chamber dimensions. Necessity for matching of these parameters in a wide variation range of load and crankshaft speed was identified and proved.     

Thermal state of the shell for supersonic part of the ramjet nozzle

A mathematical model describing the temperature distribution in a non-cooled nozzle shell was constructed. Analysis of this model showed that the extreme temperatures are permissible for some modern and promising heat-resistant composite materials.     

Control of flight vehicles with the adjustable center of mass

We resolve a problem how to control the longitudinal angular motion of flight vehicles (FV) having a system to displace the center of mass in the transverse direction. A structure is determined and a control law is established to start up and shutdown the engines. Formulas to determine the control parameters are obtained.     

Methodological foundations and areas for improvement of the aircraft design process

The paper considers the methodological foundations of aircraft design facilitated by advanced information technologies. We outline some promising areas of project management perfection and methods of solving the problems at all stages of the aircraft life cycle.     

A method of determining the aircraft motion parameters at landing

The paper contains a method of determining the aircraft motion parameters at landing based on the application of the ground optoelectronic system. The method proposed provides the certification of present-day instrument landing systems.     

Cross-correlation function computing pattern in the FPGA architecture

The complexity has been evaluated for the devices determined on the basis of the structural pattern proposed, which are implemented on the distributed programmable-architecture computing systems.