Development and Validation of the Technique for Simulating Thermal and Strain State of Strapdown Inertial Navigation System Parts

Abstract

This article shows an importance of a reliable assessment of thermoelastic deformations of the axles of sensitive elements and their subsequent algorithmic compensation in order to improve the accuracy of strapdown inertial navigation system. For this purpose, a technique for simulation of temperature fields of a strapdown inertial navigation system has been developed using the ANSYS software. The technique combines several methodological approaches to the preparation of computational models used to simulate the thermal and strain state of instrument parts, to calculate free-convective air circulation in the internal space, as well as a methodical approach to solving the problem of gas dynamics and heat transfer. To validate the developed technique bench testing was carried out with temperature measurements during device self-heating. A satisfactory agreement between the calculated and experimental data was established, indicating the adequacy of the chosen mathematical model and the developed calculation scheme for a strapdown inertial navigation system. Based on the validation results, it is recommended to use the developed technique for predicting the thermal and stress-strain state of a strapdown inertial navigation system parts and for determining the deviation angles of the sensitive element axles in various conditions, including transient operating modes. A methodical approach is proposed for calculating the angles of sensitive elements, on the basis of using special two-node finite elements and relations for Bryant angles describing the relative position of two coordinate systems in space