Vol 9, No 3 (2018)

This paper is dedicated to the history of development of a gyroscope based on the nuclear magnetic resonance (NMR) effect, in the USSR and Russia. The paper presents early references to the idea of using the electrons and other elementary particles, as well as atoms as a working substance in gyroscopy. The main stages of development of a NMR-gyroscope construction principles are briefly described. Works on spin oscillators and stabilizers based on mercury isotopes and on exchange-oriented nuclei of noble gases are discussed. The paper shows how these stages are linked with emerging new areas (disciplines) of applied nuclear physics, such as spectroscopy (electronic paramagnetic resonance and NMR), optical pumping, and exchange orientation.

Vertical-cavity surface-emitting lasers (VCSELs) of 895 nm spectral range, with fixed direction of output polarization have been developed. These lasers provide single-mode output power of over 1 mW at an operational temperature of 60°С, at orthogonal polarization suppression ratio (OPSR) about 20 dB. The designed VCSELs were used in a laser source for a perspective compact nuclear magnetic resonance gyroscope. The designed laser source provides precise tuning of wavelength to the Cs¹³³ D1 spectral line, and formation of collimated output beam.

The laser gyro frequency response is studied by means of numerical simulation using a phase equation. The calculation results are compared to the results of experimental measurements on a precision dynamic test-bench. Quantitative relationship between the threshold value of static lock-in zone and frequency response distortions is established. Numerical methods helped to obtain and experimentally confirm the quantitative dependence of frequency response distortion on the amplitude and frequency of meander-shaped dither. It is shown that the dither shape significantly affects the frequency response form. Furthermore, it is demonstrated that frequency-response distortions depend on conditions of its measurement, in particular, on the time. The conducted research allows dither parameters to be optimized with a view to increase the accuracy of measurements using laser gyroscopes.

This paper presents a novel on line algorithm for maneuver classification of a moving vehicle with six degrees of freedom, using on-board MEMS IMU’s data (three accelerometers and three rate gyros). The classification is either discrete (i.e. high, low or no maneuver), or continuous (a value that reflects the intensity of the maneuver). It should be mentioned that there is no explicit solution for this problem in any research paper previously published, due to the inability to find a direct mathematical model capable of characterizing this problem, despite its importance and its impact in improving the functioning of navigation systems. The proposed algorithm is based on a machine learning technique called logistic regression, which is a discriminative probabilistic classification model. Computer simulations, using MEMS IMU’s data taken from real experiments of an UAV, showed the effectiveness of the proposed algorithm, taking into account the sampling time, and the suitability for a wide spectrum of applications.

The paper presents brief history of development of new autonomous navigation equipment, a radio astronavigation system (radiosextant), and discusses new technological solutions implemented in the radiosextant, as well as the reasons for stopping its further development.