In the modern world, information transmission systems, telecommunication and satellite navigation systems, as well as metrological services play an important role in our lives. However, the development of these systems leads to the constant need to upgrade the currently used quantum frequency standards. To improve the short-term stability of the frequency standard, a new method has been developed to upgrade the oscillator unit and the frequency standard output amplifiers. In the course of experimental studies of the metrological characteristics of the quantum frequency standard based on rubidium-87 atoms, the effectiveness of the new development was shown.
The necessity of increasing the metrological characteristics of the quantum frequency standard on rubidium-87 atoms is substantiated. It is noted that the main destabilizing factor that reduces the accuracy of frequency determination is temperature. To control it, the quantum standard uses thermostating and thermoregulation. It is established that the systems currently used for laser and optical components cannot provide the necessary temperature stability, which is required to improve the metrological characteristics of the quantum standard. A new circuit of a quantum frequency standard temperature controller with a rubidium gas cell using a PID controller and an instrument amplifier has been developed, and its operation in the LTspice environment has been simulated. Transient processes in the circuit of the thermostat are analyzed. A decrease in the influence of temperature on the optical components and characteristics of the laser in the quantum frequency standard has been established (the signal-to-noise ratio in the recorded optical signal has increased), which, in turn, improves the short-term stability of the QFS frequency by 7-10%, synchronization of time scales in the satellite navigation system, increases the accuracy of determining the coordinates of the object.
The subject of the work is a description of algorithms for determining the number of signals in the implementation of the method of principal components in correlation analysis, and analysis of the quality of their functioning. Algorithms are intended for use in the digital antenna array of GNSS navigation user equipment (NUE). The paper discusses the results of the analysis of characteristics of several algorithms for operative estimation of the signal subspace dimensionality of the eigenvectors of the covariance matrix of data formed from multichannel data samples during the spatial processing of GNSS navigation signals (NS). Data on the signal-to-noise ratio (energy potential) of the NS at the output of digital correlator after spatial processing with the determination of the number of interferences are presented.
The paper provides the assessment of GNSS System Time offsets from their reference time scales for the period of January-November 2021. The influence of the offset deviations on the accuracy of time transfer by GNSS has been analyzed.
The necessity of upgrading the quantum frequency standard based on rubidium-87 atoms is substantiated. So in the design of quantum frequency standards, individual blocks are mainly upgraded. A solution is proposed to improve the design of the rubidium frequency standard. A block diagram of the part of the standard that is being upgraded is presented. The results of mathematical modeling of the output characteristics of the frequency converter are presented. A forecast of improvement of the metrological characteristics of the quantum frequency standard is obtained.
